HK1239485B - Energy delivery systems and uses thereof - Google Patents

Description

Energy delivery systems and their uses

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Patent Application No. 201280067592.8, filed December 21, 2012, and entitled “Energy Delivery System and Uses Thereof.” This application claims priority to co-pending U.S. Provisional Patent Application No. 61/578,738, filed December 21, 2011, which is hereby incorporated by reference in its entirety.

Technical Field

The present invention relates to comprehensive systems, devices, and methods for delivering energy to tissue for a variety of applications, including medical procedures (e.g., tissue ablation, resection, cauterization, vascular thrombosis, treatment of arrhythmias and rhythm disorders, electrosurgery, tissue harvesting, etc.). In certain embodiments, systems, devices, and methods are provided for treating a tissue region (e.g., a tumor) by applying energy.

Background Art

Ablation is an important therapeutic strategy used to treat certain tissues, such as benign and malignant tumors, arrhythmias, heart rhythm disturbances, and tachycardias. Most approved ablation systems utilize radiofrequency (RF) energy as the ablative energy source. Consequently, a variety of RF-based catheters and power supplies are currently available to physicians. However, RF energy has several limitations, including rapid energy dissipation in surface tissues, resulting in shallow "burns" and an inability to penetrate deeper into tumor or arrhythmic tissue. Another limitation of RF ablation systems is the tendency for eschar and blood clot formation on the energy-emitting electrodes, which limits further energy deposition.

Microwave energy is an effective energy source for heating biological tissue and is used in applications such as cancer treatment and preheating of blood prior to infusion. Therefore, in view of the shortcomings of traditional ablation techniques, there has been a lot of interest recently in using microwave energy as an ablative energy source. Compared to RF, the advantages of delivering microwave energy are deeper penetration into tissue, insensitivity to charring, no need for grounding, more reliable energy deposition, faster tissue heating, and the ability to produce larger thermal damage than RF, which greatly simplifies the actual ablation procedure. Therefore, there are a variety of devices under development that utilize electromagnetic energy in the microwave frequency range as an ablative energy source (see, for example, U.S. Patents 4,641,649, 5,246,438, 5,405,346, 5,314,466, 5,800,494, 5,957,969, 6,471,696, 6,878,147 and 6,962,586; each of which is incorporated herein by reference in its entirety).

Unfortunately, current devices configured to deliver microwave energy have drawbacks. For example, due to practical limitations on power and treatment time, current devices produce relatively small lesions. The power limitations of current devices manifest themselves in the smaller power-carrying capacity of the feeder lines. However, larger diameter feeder lines are undesirable because they are less easily inserted percutaneously and may increase the incidence of surgical complications. Microwave devices are also limited to a single antenna for most applications, thereby limiting the ability to treat multiple areas simultaneously or to place multiple antennas in close proximity to create larger tissue heating zones. Furthermore, heating of the feeder lines at high power can cause burns around the device's insertion area.

There is a need for improved systems and devices for delivering energy to a tissue region. Furthermore, there is a need for improved systems and devices capable of transmitting microwave energy without corresponding microwave energy loss. Furthermore, there is a need for systems and devices capable of transcutaneously delivering microwave energy to tissue of a subject without undesirable tissue burns. Furthermore, there is a need for systems for delivering a desired amount of microwave energy without requiring physically large, invasive components.

Summary of the Invention

The present invention relates to comprehensive systems, devices, and methods for delivering energy to tissue for a variety of applications, including medical procedures (e.g., tissue ablation, resection, cauterization, vascular thrombosis, treatment of arrhythmias and rhythm disorders, electrosurgery, tissue harvesting, etc.). In certain embodiments, systems, devices, and methods are provided for treating a tissue region (e.g., a tumor) by applying energy.

The present invention provides systems, devices, and methods that employ components for delivering energy to a tissue region (e.g., a tumor, a lumen, an organ, etc.). In some embodiments, the system includes an energy delivery device and one or more of the following: a processor; a power source; a device for directing, controlling, and delivering power (e.g., a power splitter); an imaging system; a tuning system; and a temperature regulation system. The present invention is not limited to a particular type of energy delivery device. The present invention contemplates the use of any known or future developed energy delivery device in the systems of the present invention. In some embodiments, existing commercial energy delivery devices are used. In other embodiments, improved energy delivery devices with optimized characteristics (e.g., small size, optimized energy delivery, optimized impedance, optimized heat dissipation, etc.) are used. In some such embodiments, the energy delivery device is configured to deliver energy (e.g., microwave energy) to the tissue region. In some embodiments, the energy delivery device is configured to deliver microwave energy with an optimized characteristic impedance (e.g., configured to operate with a characteristic impedance greater than 50 Ω) (e.g., between 50 Ω and 90 Ω; e.g., greater than 50 ..., 55, 56, 57, 58, 59, 60, 61, 62, ... 90 Ω, preferably 77 Ω) (see, e.g., U.S. patent application Ser. No. 11/728,428; incorporated herein by reference in its entirety).

A significant source of undesirable overheating of the device is dielectric heating of the insulator (e.g., coaxial insulator), which can potentially lead to collateral tissue damage. The energy delivery device of the present invention is designed to prevent undesirable device overheating. The energy delivery device is not limited to a particular method for preventing undesirable device heating. In some embodiments, the device utilizes circulation of a coolant. In some embodiments, the device is configured to detect an undesirable temperature increase within the device (e.g., along the outer conductor) and automatically or manually reduce such undesirable temperature increase by flowing coolant through the coolant channel.

In some embodiments, energy delivery devices have improved cooling properties. For example, in some embodiments, the devices allow for the use of coolant without increasing the device's diameter. This contrasts with existing devices, which require the coolant to flow through an outer sleeve or increase the device's diameter to accommodate the coolant flow. In some embodiments, the energy delivery device includes one or more coolant channels therein to reduce unnecessary heat dissipation (see, for example, U.S. patent application Ser. No. 11/728,460; incorporated herein by reference in its entirety). In some embodiments, the energy delivery device includes a tube (e.g., a needle, plastic tubing, etc.) extending the length of the device or partially extending the length of the device. The tube is designed to prevent overheating of the device due to the circulation of coolant material. In some embodiments, the channel or tube replaces material from a dielectric element located between the inner and outer conductors of a coaxial cable. In some embodiments, the channel or tube replaces or substantially replaces the dielectric material. In some embodiments, the channel or tube replaces a portion of the outer conductor. For example, in some embodiments, a portion of the outer conductor is removed or shaved to create the channel for the coolant to flow. One such embodiment is illustrated in FIG. 12 . In this embodiment, coaxial cable 900 comprises an outer conductor 910, an inner conductor 920, and dielectric material 930. In this embodiment, a region 940 of the outer conductor has been removed to create space for coolant flow. The only remaining outer conductor material, defining or substantially defining the coaxial cable, is at a distal region 950 and a proximal region 960. A thin strip of conductive material 970 connects distal region 950 and proximal region 960. In this embodiment, a thin channel 980 is cut from the conductive material at proximal region 960 to allow coolant to flow into region 940 where the outer conductive material has been removed (or fabricated to contain no outer conductive material). The present invention is not limited to the size or shape of the channel, as long as it is capable of transporting the coolant. For example, in some embodiments, the channel is a linear path extending the length of the coaxial cable. In some embodiments, a spiral channel is employed. In some embodiments, a tube or channel replaces or substitutes for at least a portion of the inner conductor. For example, a large portion of the inner conductor could be replaced with coolant channels, leaving only small sections of metal near the proximal and distal ends of the device to allow for tuning, with these sections connected by thin strips of conductive material. In some embodiments, a region of internal space is created within the inner or outer conductor to create one or more channels for the coolant. For example, the inner conductor could be provided as a hollow tube of conductive material with a coolant channel in the center. In such embodiments, the inner conductor could be used for either inflow or outflow (or both) of the coolant.

In some embodiments, a coolant tube is disposed within a device having a plurality of channels for introducing and removing coolant through the device. The device is not limited to a specific location of the tube (e.g., a coolant needle) within the dielectric material. In some embodiments, the tube is positioned along the outer edge of the dielectric material, in the middle of the dielectric material, or anywhere within the dielectric material. In some embodiments, the dielectric material is preformed with channels designed to receive and secure the tube. In some embodiments, a handle is attached to the device, wherein the handle is configured to, for example, control the flow of coolant into or out of the tube. In some embodiments, the tube is flexible. In some embodiments, the tube is non-flexible. In some embodiments, some portions of the tube are flexible while other portions are non-flexible. In some embodiments, the tube is compressible. In some embodiments, the tube is incompressible. In some embodiments, some portions of the tube are compressible while other portions are incompressible. The tube is not limited to a specific shape or size. In some embodiments, the tubing is a coolant syringe (e.g., a 29-gauge syringe or equivalent) that fits within a coaxial cable having a diameter equal to or smaller than a 12-gauge syringe. In some embodiments, the exterior of the tubing is coated with an adhesive and/or grease to secure the tubing or allow for sliding movement within the device. In some embodiments, the tubing has one or more holes along its length that allow for the release of coolant into desired areas of the device. In some embodiments, these holes are initially blocked with a meltable material, requiring a specific heating threshold to melt the material and release the coolant through the specific hole or holes affected. Thus, coolant is released only in areas where a threshold heating level has been reached.

In some embodiments, coolant is preloaded into the antenna, handle, or other components of the device. In other embodiments, coolant is added during use. In some preloaded embodiments, liquid coolant is preloaded into, for example, the distal end of the antenna under conditions that create a self-sustaining vacuum. In some such embodiments, as the liquid coolant vaporizes, more fluid is drawn into the vacuum.

The present invention is not limited by the nature of the coolant material used. Coolants include, but are not limited to, liquids and gases. Exemplary coolant fluids include, but are not limited to, one or more of the following, or a combination thereof: water, ethylene glycol, air, an inert gas, carbon dioxide, nitrogen, helium, sulfur hexafluoride, ionic solutions (e.g., sodium chloride with or without potassium and other ions), dextrose in water, lactated Ringer's solution, organic chemical solutions (e.g., ethylene glycol, diethylene glycol, or propylene glycol), oils (e.g., mineral oil, silicone oil, fluoroalkane oil), liquid metals, Freons, halogenated methanes, liquefied propane, other halogenated alkanes, anhydrous ammonia, and sulfur dioxide. In some embodiments, the coolant is a gas compressed to or near its critical point. In some embodiments, cooling occurs at least in part by varying the concentration, pressure, or volume of the coolant. For example, cooling can be achieved using a gas coolant utilizing the Joule-Thomson effect. In some embodiments, cooling is provided by a chemical reaction. The device is not limited to a specific type of chemical reaction that reduces temperature. In some embodiments, the chemical reaction that reduces temperature is an endothermic reaction. The device is not limited to a specific method for applying an endothermic reaction to prevent undesirable heating. In some embodiments, first and second chemicals are flowed into the device to cause them to react, thereby lowering the device's temperature. In some embodiments, the device is prepared with the first and second chemicals preloaded within the device. In some embodiments, the chemicals are separated by a barrier that is removed when needed. In some embodiments, the barrier is configured to melt upon exposure to a predetermined temperature or temperature range. In such embodiments, the device initiates the endothermic reaction only when a heating level is reached that warrants cooling. In some embodiments, multiple different barriers are positioned throughout the device so that localized cooling occurs only in those portions of the device where undesirable heating occurs. In some embodiments, the barrier is a bead that surrounds one of the two chemicals. In some embodiments, the barrier is a wall (e.g., a washer-shaped disk) that melts to combine the two chemicals. In some embodiments, the barrier is composed of wax configured to melt at a predetermined temperature. The device is not limited to a specific type, type, or amount of meltable material. In some embodiments, the meltable material is biocompatible. The device is not limited to a specific type, type, or amount of the first and second chemicals, as long as their combination results in a chemical reaction that lowers the temperature. In some embodiments, the first material comprises barium hydroxide octahydrate crystals, and the second material is dried ammonium chloride. In some embodiments, the first material is water, and the second material is ammonium chloride. In some embodiments, the first material is thionyl chloride (SOCl ₂ ), and the second material is cobalt(II) sulfate heptahydrate. In some embodiments, the first material is water, and the second material is ammonium nitrate. In some embodiments, the first material is water, and the second material is potassium chloride. In some embodiments, the first material is acetic acid, and the second material is sodium carbonate. In some embodiments, a fusible material is used that reduces heat by melting and flowing in a manner that reduces heat on the outer surface of the device.

In some embodiments, an energy delivery device prevents undesirable heating and/or maintains desired energy delivery performance by adjusting the amount of energy emitted from the device (e.g., adjusting the wavelength of energy resonating from the device) as temperature increases. The device is not limited to a particular method for adjusting the amount of energy emitted from the device. In some embodiments, the device is configured such that the wavelength of energy resonating from the device is adjusted when the device reaches a certain threshold temperature or when the device is heated within a certain range. The device is not limited to a particular method for adjusting the wavelength of energy resonating from the device. In some embodiments, the device includes a material that changes volume with increasing temperature. This change in volume is used to move or adjust components of the device that affect energy delivery. For example, in some embodiments, a material that expands with increasing temperature is used. This expansion is used to move the distal tip of the device outward (increasing its distance from the proximal end of the device), thereby changing the device's energy delivery performance. This is particularly applicable to center-fed dipole embodiments of the present invention.

In certain embodiments, the present invention provides a device comprising an antenna configured for delivering energy to tissue, wherein the distal end of the antenna comprises a center-fed dipole assembly comprising a rigid hollow tube surrounding a conductor, wherein a stylet is secured within the hollow tube (e.g., a titanium stylet). In some embodiments, the diameter of the hollow tube is equal to or smaller than that of a 20-gauge needle. In some embodiments, the diameter of the hollow tube is equal to or smaller than that of a 17-gauge needle. In some embodiments, the diameter of the hollow tube is equal to or smaller than that of a 12-gauge needle. In some embodiments, the device further comprises a tuning element for adjusting the amount of energy delivered to the tissue. In some embodiments, the device is configured to provide sufficient energy to ablate tissue or induce thrombosis. In some embodiments, the conductor extends midway through the hollow tube. In some embodiments, the hollow tube has a length of λ/2, where λ is the wavelength of the electromagnetic field in the tissue medium. In some embodiments, an expandable material is positioned near the stylet such that when the temperature of the device increases, the expandable material expands and pushes against the stylet, displacing the stylet and altering the energy delivery characteristics of the device. In some embodiments, an expandable material is positioned behind (near) a metal disk that provides a resonant element for a center-fed dipole device. As the material expands, the disk is pushed further apart, thereby adjusting the tuning of the device. The expandable material is preferably selected so that the rate of expansion coincides with the change in energy delivery for optimal results. However, it should be understood that any change in the desired direction is found to be suitable for use with the present invention. In some embodiments, the expandable material is wax.

In some embodiments, the device has a handle attached to the device, wherein the handle is configured, for example, to control the flow of coolant into and out of the coolant channels. In some embodiments, only the handle is cooled. In some embodiments, the handle is configured to deliver a gaseous coolant compressed to or near its critical point. In other embodiments, the handle and attached antenna are cooled. In some embodiments, the handle automatically delivers coolant into and out of the coolant channels after a certain period of time and/or when the device reaches a certain threshold temperature. In some embodiments, the handle automatically stops delivering coolant into and out of the coolant channels after a certain period of time and/or when the temperature of the device drops below a certain threshold temperature. In some embodiments, coolant flow through the handle is manually controlled. In some embodiments, the handle has one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., indicator lights (e.g., LED lights)) thereon. In some embodiments, the lights are configured for identification purposes. For example, in some embodiments, the lights are used to distinguish between different stylets (e.g., activation of the first stylet displays one light, the second stylet displays two lights, the third stylet displays three lights, or each stylet has its own designated light, etc.). In some embodiments, the lights are used to identify the occurrence of an event (e.g., delivery of coolant through the device, delivery of power through the device, movement of various probes, change in a set value (e.g., temperature, position) within the device, etc.). The handle is not limited to a particular display method (e.g., flashing, alternating colors, solid colors, etc.).

In some embodiments, the energy delivery device has a center-fed dipole assembly therein (see, e.g., U.S. patent application Ser. No. 11/728,457; incorporated herein by reference in its entirety). In some embodiments, the energy delivery device comprises a catheter having multiple segments for transmitting and emitting energy (see, e.g., U.S. patent application Ser. Nos. 11/237,430, 11/237,136, and 11/236,985; each incorporated herein by reference in its entirety). In some embodiments, the energy delivery device includes a three-axis microwave detector with optimized tuning capabilities to reduce reflected heat losses (see, e.g., U.S. Patent No. 7,101,369; see also U.S. Patent Application Nos. 10/834,802, 11/236,985, 11/237,136, 11/237,430, 11/440,331, 11/452,637, 11/502,783, 11/514,628, and International Patent Application No. PCT/US05/14534; incorporated herein by reference in their entireties). In some embodiments, the energy delivery device transmits energy through a coaxial transmission line (e.g., a coaxial cable) having an air or other gas as the dielectric core (see, e.g., U.S. Patent Application No. 11/236,985; incorporated herein by reference in its entirety). In some such embodiments, the material supporting the structure of the device between the inner and outer conductors can be removed prior to use. For example, in some embodiments, the material is made of a dissolvable or meltable material that is removed before or during use. In some embodiments, the material is meltable and removed during use (upon exposure to heat) to optimize the energy delivery properties of the device over time (e.g., in response to temperature changes in tissue, etc.).

The present invention is not limited to a specific coaxial transmission line shape. In fact, in some embodiments, the shape of the coaxial transmission line and/or dielectric element is adjustable to suit specific needs. In some embodiments, the cross-sectional shape of the coaxial transmission line and/or dielectric element is circular. In some embodiments, the cross-sectional shape is non-circular (e.g., elliptical, etc.). This shape can be applied to the entire coaxial cable or to only one or more subcomponents. For example, an elliptical dielectric material can be placed within a circular outer conductor. This has the advantage of creating two channels, which can be used, for example, to circulate a coolant. As another example, a square/rectangular dielectric material can be placed within a circular conductor. This has the advantage of creating four channels, for example. Different polygonal cross-sectional shapes (e.g., pentagonal, hexagonal, etc.) can be used to create a variety of channels in different numbers and shapes. The cross-sectional shape does not need to be the same throughout the entire length of the cable. In some embodiments, a first shape is used for a first region of the cable (e.g., the proximal end), and a second shape is used for a second region of the cable (e.g., the distal end). Irregular shapes are also possible. For example, a dielectric material with sawtooth-like grooves extending along its length can be used in a circular outer conductor to create a single channel of any desired size and shape. In some embodiments, the channel provides space for feeding coolant, needles, or other required components into the shape without increasing the final outer diameter of the device.

Similarly, in some embodiments, the antenna of the present invention has a non-circular cross-sectional shape along its length or for one or more subsections of its length. In some embodiments, the antenna is non-cylindrical but contains a cylindrical coaxial cable. In other embodiments, the antenna is non-cylindrical and contains a non-cylindrical coaxial cable (e.g., matching the antenna's shape or having a different non-cylindrical shape). In some embodiments, having any one or more components with a non-cylindrical shape (e.g., the catheter, the antenna's housing, the coaxial cable's outer conductor, the coaxial cable's dielectric material, the coaxial cable's inner conductor) allows for the creation of one or more channels within the device, which can be used for, among other reasons, circulating coolant. Non-circular shapes, particularly the antenna's outer diameter, have also been found suitable for certain medical or other applications. For example, the shape can be selected to maximize flexibility or access specific internal body locations. The shape can also be selected to optimize energy transmission. The shape (e.g., the non-cylindrical shape) can also be selected to maximize the device's rigidity and/or strength, particularly for devices with small diameters.

In certain embodiments, the present invention provides a device comprising an antenna, wherein the antenna comprises an inner conductor surrounding an outer conductor, wherein the inner conductor is designed to receive and transmit energy, wherein the outer conductor has at least one gap positioned therein along the periphery of the outer conductor, wherein multiple energy peaks are generated along the length of the antenna, the positions of these energy peaks being controlled by the positions of the gaps. In some embodiments, the energy is microwave energy and/or radio frequency energy. In some embodiments, the outer conductor has two gaps therein. In some embodiments, the antenna comprises a dielectric layer disposed between the inner conductor and the outer conductor. In some embodiments, the dielectric layer has a conductivity near zero. In some embodiments, the device further comprises a stylet. In some embodiments, the diameter of the inner conductor is approximately 0.013 inches or less.

In some embodiments, any gaps or inconsistencies or irregularities on the outer surface of the outer conductor or device are filled with a material to provide a smooth, uniform, or substantially smooth, uniform outer surface. In some embodiments, a heat-resistant resin is used to fill the gaps, inconsistencies, and/or irregularities. In some embodiments, the resin is biocompatible. In other embodiments, it is not biocompatible, but can be coated with a biocompatible material, for example. In some embodiments, the resin can be configured to any desired size or shape. Thus, after hardening, the resin can be used to provide the device with a sharp stylet tip or any other desired physical shape.

In some embodiments, the device includes a sharp stylet tip. The stylet tip can be made of any material. In some embodiments, the tip is made of a cured resin. In some embodiments, the tip is metal. In some embodiments, the stylet tip is made of titanium or a titanium equivalent. In some embodiments, the stylet tip is red-hot to produce zirconium oxide or a zirconium oxide equivalent. In some such embodiments, the metal tip is an extension of the metal portion of the antenna and is electrically active.

In some embodiments, the energy delivery device is configured to deliver energy to a tissue region within a system that includes a processor, a power source, a device for directing, controlling, and delivering power (e.g., a power splitter with the ability to individually control the power delivered to each antenna), an imaging system, a tuning system, and/or a temperature measurement and regulation system.

The present invention is not limited to a particular type of processor. In some embodiments, the processor is designed to, for example, receive information from components of the system (e.g., a temperature monitoring system, an energy delivery device, a tissue impedance monitoring component, etc.), display such information to a user, and manipulate (e.g., control) other components of the system. In some embodiments, the processor is configured to operate within a system that includes an energy delivery device, a power source, a device for directing, controlling, and transmitting power (e.g., a power divider), an imaging system, a tuning system, and/or a temperature regulation system.

The present invention is not limited to a particular type of power supply. In some embodiments, the power supply is configured to provide any desired type of energy (e.g., microwave energy, radiofrequency energy, radiation, cryogenic energy, electroporation, high-intensity focused ultrasound, and/or combinations thereof). In some embodiments, the power supply utilizes a power splitter to allow energy to be delivered to two or more energy delivery devices. In some embodiments, the power supply is configured to operate within a system that includes a power splitter, a processor, an energy delivery device, an imaging system, a tuning system, and/or a temperature regulation system.

The present invention is not limited to a particular type of imaging system. In some embodiments, the imaging system utilizes an imaging device (e.g., an endoscopic device, a stereotactic computer-assisted neurosurgery navigation device, a thermal sensor positioning system, a motion velocity sensor, a steering line system, intraprocedural ultrasound, fluoroscopy, computer-assisted tomography magnetic resonance imaging, a nuclear medicine imaging device triangulation imaging, interstitial ultrasound, microwave imaging, ultrasound tomography, dual-energy imaging, thermoacoustic imaging, infrared and/or laser imaging, electromagnetic imaging) (see, e.g., U.S. Patent Nos. 6,817,976, 6,577,903, 5,697,949, 5,603,697, and International Patent Application No. WO06/005,579; each of which is incorporated herein by reference in its entirety). In some embodiments, the system utilizes an endoscopic camera, an imaging component, and/or a navigation system that allows or assists in the placement, positioning, and/or monitoring of any item used with the energy system of the present invention. In some embodiments, the imaging system is configured to provide positional information of specific components of the energy delivery system (e.g., the position of the energy delivery device). In some embodiments, the imaging system is configured to operate within a system that includes a processor, an energy delivery device, a power supply, a tuning system, and/or a temperature regulation system. In some embodiments, the imaging system is located within the energy delivery device. In some embodiments, the imaging system provides qualitative information about the properties of the ablation zone (e.g., diameter, length, cross-sectional area, volume). The imaging system is not limited to a specific technology for providing qualitative information. In some embodiments, the technology for providing qualitative information includes, but is not limited to, time domain reflectometry, time-of-flight pulse detection, frequency modulated distance detection, natural mode or resonant frequency detection, or reflection and transmission at arbitrary frequencies, all based on a single interstitial device or in collaboration with other interstitial devices or external equipment. In some embodiments, the interstitial device provides signals and/or detection for imaging (e.g., electroacoustic imaging, electromagnetic imaging, electrical impedance tomography).

The present invention is not limited to a particular tuning system. In some embodiments, the tuning system is configured to allow adjustment of variables within the energy delivery system (e.g., the amount of energy delivered, the frequency of energy delivered, the amount of energy delivered to one or more of the multiple energy devices provided in the system, the amount or type of coolant provided, etc.). In some embodiments, the tuning system includes sensors that provide feedback to a user or a processor that continuously or temporally monitors the function of the energy delivery device. The sensors can record and/or report any number of properties, including, but not limited to, thermal energy (e.g., temperature) at one or more locations of a component of the system, thermal energy at tissue, tissue characteristics, qualitative information about the region, etc. The sensors can take the form of imaging devices such as CT, ultrasound, magnetic resonance imaging, fluoroscopy, nuclear medicine imaging, or any other imaging device. In some embodiments, particularly for research applications, the system records and stores information for future optimization of the system generally and/or for optimizing energy delivery under specific conditions (e.g., patient type, tissue type, size and shape of the target region, location of the target region, etc.). In some embodiments, the tuning system is configured to operate within a system that includes a processor, an energy delivery device, a power supply, and an imaging and/or temperature regulation system. In some embodiments, imaging or other control components provide feedback to the ablation device so that the output power (or other control parameters) can be adjusted to provide optimal tissue response.

The present invention is not limited to a particular temperature regulation system. In some embodiments, the temperature regulation system is designed to reduce unnecessary heating of various system components (e.g., an energy delivery device) or maintain target tissue within a certain temperature range during a medical procedure (e.g., tissue ablation). In some embodiments, the temperature regulation system is configured to operate within a system that includes a processor, an energy delivery device, a power supply, a device for directing, controlling, and transmitting power (e.g., a power divider), a tuning system, and/or an imaging system. In some embodiments, the temperature regulation system is designed to cool the energy delivery device to a temperature sufficient to temporarily adhere the device to internal patient tissue to prevent movement of the energy delivery device during the procedure (e.g., during an ablation procedure).

In some embodiments, the system further includes a temperature monitoring or reflected power monitoring system to monitor the temperature or reflected power of various components of the system (e.g., the energy delivery device) and/or tissue regions. In some embodiments, the monitoring system is configured to modify (e.g., prevent, reduce) the delivery of energy to a specific tissue region if, for example, the temperature or the amount of reflected energy exceeds a predetermined value. In some embodiments, the temperature monitoring system is configured to modify (e.g., increase, decrease, maintain) the delivery of energy to a specific tissue region to maintain the tissue or energy delivery device at a preferred temperature or within a preferred temperature range.

In some embodiments, the system further includes an identification or tracking system configured, for example, to prevent the use of previously used components (e.g., non-sterile energy delivery devices) and thereby identify the nature of one component of the system so that other components of the system can be appropriately adjusted for compatibility or optimized functionality. In some embodiments, the system reads barcodes or other information-transmitting elements associated with the components of the system of the present invention. In some embodiments, the connections between the components of the system are altered (e.g., disconnected) after use to prevent additional use. The present invention is not limited to the types of components used in the system or the intended use. In fact, the device can be configured in any desired manner. Similarly, the system and device can be used in any application where energy is to be delivered. These applications include any and all medical, veterinary, and research applications. However, the system and device of the present invention can also be used in agricultural facilities, manufacturing facilities, machinery facilities, or any other application where energy is to be delivered.

In some embodiments, the system is configured for percutaneous, intravascular, intracardiac, laparoscopic, or surgical delivery of energy. Similarly, in some embodiments, the system is configured to deliver energy via a catheter, through a surgically extended opening, and/or through a body orifice (e.g., mouth, ear, nose, eye, vagina, penis, anus) (e.g., N.O.T.E.S. procedures). In some embodiments, the system is configured to deliver energy to a target tissue or region. The present invention is not limited by the nature of the target tissue or region. Uses include, but are not limited to, treatment of cardiac arrhythmias, tumor ablation (benign and malignant), bleeding control during surgery, bleeding control after trauma, any other bleeding control, soft tissue removal, tissue resection and harvesting, treatment of varicose veins, intracavitary tissue ablation (e.g., for the treatment of esophageal diseases such as Bartholin's esophagus and esophageal adenocarcinoma), bone tumors, treatment of normal bone and benign bone conditions, intraocular uses, cosmetic surgical uses, treatment of central nervous system disorders including brain tumors and electrical perturbations, sterilization procedures (e.g., fallopian tube removal), and cauterization of blood vessels or tissue for any purpose. In some embodiments, surgical applications include ablative therapy (e.g., to achieve coagulative necrosis). In some embodiments, surgical applications include tumor ablation of a target, such as a metastatic tumor. In some embodiments, the device is configured to be moved and positioned at any desired location, including but not limited to the brain, neck, chest, abdomen, and pelvis, with minimal damage to tissue or organism. In some embodiments, the system is configured for guided delivery, such as by computed tomography, ultrasound, magnetic resonance imaging, fluoroscopes, and the like.

In certain embodiments, the present invention provides a method for treating a tissue region, comprising: providing the tissue region and a system described herein (e.g., an energy delivery device, and at least one of the following components: a processor, a power source, a device for directing, controlling, and transmitting power (e.g., a power splitter), a temperature monitor, an imager, a tuning system, and/or a cooling system); positioning a portion of the energy delivery device near the tissue region, and using the device to deliver an amount of energy to the tissue region. In some embodiments, the tissue region is a tumor. In some embodiments, the energy delivery results in, for example, ablation of thrombosis in the tissue region and/or blood vessel and/or electroporation of the tissue region. In some embodiments, the tissue region is a tumor. In some embodiments, the tissue region comprises one or more of the following: heart, liver, genitalia, stomach, lung, large intestine, small intestine, brain, neck, bone, kidney, muscle, tendon, blood vessel, prostate, bladder, spinal cord, skin, vessels, fingernails, and toenails. In some embodiments, the processor receives information from the sensors and monitors and controls the other components of the system. In some embodiments, the energy output of the power source is varied as needed to optimize treatment. In some embodiments where more than one energy delivery element is provided, the amount of energy delivered to each delivery element is optimized to achieve the desired result. In some embodiments, the temperature of the system is monitored by a temperature sensor and reduced by activating a cooling system when it reaches or approaches a threshold level. In some embodiments, the imaging system provides information to a processor that is displayed to a user of the system and can be used in a feedback loop to control the output of the system.

In some embodiments, energy is delivered to tissue regions from different locations within the device at different intensities. For example, certain areas of the tissue region can be treated by one portion of the device, while other areas of the tissue can be treated by different portions of the device. In addition, two or more areas of the device can simultaneously deliver energy to a specific tissue region, thereby achieving constructive phase interference (e.g., where the emitted energy achieves a synergistic effect). In other embodiments, two or more areas of the device can deliver energy, thereby achieving a destructive interference effect. In some embodiments, the method also provides additional devices for achieving constructive phase interference and/or destructive phase interference. In some embodiments, the phase interference (e.g., constructive phase interference, destructive phase interference) between one or more devices is controlled by a processor, a tuning element, a user, and/or a power divider.

The systems, devices, and methods of the present invention can be used in conjunction with other systems, devices, and methods. For example, the systems, devices, and methods of the present invention can be used with other ablation devices, other medical devices, diagnostic methods and agents, imaging methods and agents, and therapeutic methods and agents. They can be used simultaneously or before or after another intervention. The present invention contemplates the use of the systems, devices, and methods of the present invention in conjunction with any other medical intervention.

Furthermore, integrated ablation and imaging systems are needed to provide feedback to the user and enable communication between the various system components. System parameters can be adjusted during the ablation process to optimize energy delivery. Furthermore, the user can more accurately determine when the procedure has been successfully completed, reducing the likelihood of failed treatments and/or treatment-related complications.

In certain embodiments, the present invention provides systems having, for example, a power supply assembly that provides a source of energy and a source of coolant; a transport assembly that transports the energy and coolant from the power supply assembly to a control center (e.g., a control box); and a procedure device hub that receives the energy and coolant from the transport assembly, the control center being located at the patient workspace; the procedure device hub including a plurality of connection ports for attaching one or more cables configured to deliver energy and/or coolant to one or more energy delivery devices. In some embodiments, the transport assembly is a low-loss cable. In some embodiments, the one or more cables configured to deliver energy to the one or more energy delivery devices are flexible, disposable cables. The procedure device hub is not limited to a particular weight. In some embodiments, the weight of the procedure device hub allows it to rest on the patient's body without causing damage and/or discomfort. In some embodiments, the procedure device hub weighs less than 10 pounds.

The system is not limited to use in a particular medical procedure. In some embodiments, the system is used in, for example, a CT scanning medical procedure and/or an ultrasound imaging procedure.

The procedure device hub is not limited to a specific position in the medical process. In fact, the procedure device hub is configured to be positioned in various structures. In some embodiments, the procedure device hub is configured to be attached to the procedure table (e.g., by the belt on the procedure table) (e.g., by the groove on the procedure table). In some embodiments, the procedure device hub is configured to be attached to the patient's clothes. In some embodiments, the procedure device hub is configured to be attached to the CT safety belt. In some embodiments, the procedure device hub is configured to be attached to the operating table ring. In some embodiments, the procedure device hub is configured to be attached to a sterile drape, which is configured to be placed on the patient.

In some embodiments, the procedure device hub further comprises a procedure device hub strap, wherein the procedure device hub strap is configured to attach to a medical procedure location (eg, a procedure table, a patient's garment, a CT safety belt, a table ring, a sterile drape, etc.).

The procedure device hub is not limited to delivering coolant to the energy delivery device in a particular manner. In some embodiments, the coolant delivered to one or more energy delivery devices is a gas delivered at a compressed pressure (e.g., at a compression pressure at or near the critical point of the coolant). In some embodiments, the coolant is a gas delivered at or near its critical point, the coolant is _CO2 .

In some embodiments, the power supply is located outside the sterile field and the procedure device hub is located within the sterile field. In some embodiments, the power supply supplies microwave energy. In some embodiments, the power supply supplies radiofrequency energy.

In certain embodiments, the present invention provides a device comprising an antenna configured to deliver energy to tissue, the antenna comprising one or more coolant tubes or channels within a coaxial cable, the tubes being configured to deliver coolant to the antenna, wherein the coolant is a gas compressed at or near its critical point. The device is not limited to a particular gas. In some embodiments, the gas is _CO2 . In some embodiments, the one or more coolant tubes or channels are located between the outer conductor and the dielectric material of the coaxial cable. In some embodiments, the one or more coolant tubes or channels are located between the inner conductor and the dielectric material of the coaxial cable. In some embodiments, the one or more coolant tubes or channels are located within the inner conductor or the outer conductor. In some embodiments, the device has a proximal region, a central region, and a distal region therein. In some embodiments, the distal region is configured to deliver energy to tissue. In some embodiments, the proximal region and/or the central region have a coolant tube or channel therein. In some embodiments, the distal portion does not have a coolant tube or channel.

In some embodiments, the device includes one or more "bonding" areas configured to facilitate tissue adhesion to the bonding areas, for example, so that the device can be stabilized in a desired position during energy delivery. In some embodiments, the bonding areas are configured to reach and maintain a temperature that causes tissue to freeze in the bonding areas. In some embodiments, the bonding areas are located in the central and/or proximal regions. The bonding areas are not limited to any specific temperature that facilitates tissue adhesion. In some embodiments, the bonding areas reach and maintain a temperature that promotes adhesion of the tissue areas by contacting an area of the energy delivery device with a circulating coolant. In some embodiments, the temperature of the bonding areas is maintained at a sufficiently low temperature that adhesion of the tissue areas occurs upon contact with the bonding areas (for example, causing the tissue areas to freeze in the bonding areas). The bonding areas are not limited to a specific material composition. In some embodiments, the bonding areas are, for example, metallic, ceramic, plastic, and/or any combination thereof. In some embodiments, a seal prevents the bonding areas from being exposed to the distal region of the device. In some embodiments, the seal is located between the bonding area and the distal region of the device, thereby preventing the bonding areas from being exposed to the distal region. In some embodiments, the seal is configured to be airtight. In some embodiments, the seal is laser welded to the device (e.g., the coaxial region). In some embodiments, the seal is induction brazed to the device (e.g., the coaxial region). In some embodiments, the seal is partially (e.g., 60%/40%; 55%/45%; 50%/50%) laser welded and induction brazed.

In some embodiments, the distal region and the central region are separated by a plug region that is designed to prevent cooling of the distal region. The plug region is not limited to a particular method for preventing cooling of the distal region. In some embodiments, the plug region is designed to contact a region with a lower temperature (e.g., a central region of an energy delivery device with a circulating coolant) without lowering its own temperature. In some embodiments, the material of the plug region is such that it can contact a material with a lower temperature without substantially lowering its own temperature (e.g., an insulating material). The plug region is not limited to a particular type of insulating material (e.g., synthetic polymers (e.g., polystyrene, condensate, polyurethane, polyisocyanurate), aerogel, fiberglass, cork).

In some embodiments, a device having a plug region allows for simultaneous exposure of tissue to both a cooled region (eg, a region of the device proximal to the plug region) and a non-cooled region (eg, a region of the device distal to the plug region).

In certain embodiments, the present invention provides a device comprising an antenna configured to deliver energy to tissue, the antenna comprising one or more cooling tubes or channels within a coaxial cable having a dielectric region having a flexible region and an inflexible region. In some embodiments, the flexible region is plastic and the inflexible region is ceramic. In some embodiments, the inflexible region is positioned at a location for highest power transmission.

In certain embodiments, the present invention provides a device comprising an antenna configured to deliver energy to tissue, the antenna comprising one or more cooling tubes or channels within a coaxial cable, the device having one or more pull wires connected to a pull wire anchor. In some embodiments, contraction of the one or more pull wires connected to the pull wire anchor reduces the flexibility of the device. In some embodiments, the one or more pull wires are designed to bend at a specific temperature (e.g., superelastic nickel titanium wire).

Experiments conducted during the development of embodiments of the present invention determined that coupling a "precision antenna" (a capacitively coupled antenna) with an existing antenna resulted in improved ablation. For example, coupling a "precision antenna" with an existing antenna resulted in a larger ablation zone compared to an antenna without such coupling. For example, coupling a "precision antenna" or "precision probe" with an existing antenna resulted in a larger spherical ablation zone compared to an antenna without such coupling. Furthermore, coupling a "precision antenna" or "precision probe" with an existing antenna resulted in a superior field pattern and reduced reflected power compared to an antenna without such coupling.

Thus, in certain embodiments, the present invention provides a precision antenna or precision probe that couples with an existing antenna. In some such embodiments, the present invention provides an ablation antenna device comprising: an antenna comprising an inner conductor; a conductive tip at a distal end of the antenna; wherein the inner conductor is not physically coupled to the conductive tip (e.g., wherein the inner conductor is capacitively coupled to the conductive tip). In some embodiments, the antenna comprises a conductive outer conductor surrounding at least a portion of the inner conductor. In some embodiments, the antenna comprises a dielectric material between the inner and outer conductors. In some embodiments, the antenna is a triaxial antenna. In some embodiments, the conductive tip comprises a trocar.

In some embodiments, the inner conductor includes a first region distal from a second region distal from a third region, wherein the third region is contained within a triaxial antenna, wherein the second region excludes the triaxial antenna's outer conductor, and wherein the first region excludes the triaxial antenna's outer conductor and dielectric material. In some embodiments, the first region is adhered to and surrounded by a metal or other conductive fitting (e.g., a brass fitting). In some embodiments, the fitting extends distally beyond the distal-most end of the inner conductor (i.e., the inner conductor passes through the proximal end of the fitting but does not reach the distal end). In some embodiments, the fitting abuts the dielectric material surrounding the inner conductor in the second region. In some embodiments, the second region includes a proximal portion containing the triaxial antenna's dielectric material and a distal portion not containing the triaxial antenna's dielectric material. In some embodiments, the distal portion of the second region includes a non-conductive sleeve (e.g., a PTFE sleeve) surrounding the inner conductor. In some embodiments, the conductive tip is attached to an insulator (e.g., a ceramic insulator) attached to the distal end of the fitting. In some embodiments, the metal fitting, the insulator, and the conductive tip are positioned and sized to create a low impedance overlap, thereby transferring energy to the conductive tip when energy is supplied to the inner conductor (e.g., such that the inner conductor is capacitively coupled to the conductive tip). In some embodiments, the metal fitting is adhered to the inner conductor with a conductive adhesive.

The present invention also provides systems that utilize such precision probes. These systems may include any other components described herein (e.g., power supplies, coolant systems), and the antennas comprising the precision probes may have any of the features or functions described herein (e.g., bonding functionality that locks the antenna to tissue via cooling). These devices and systems are applicable to any of the methods described herein.

Specifically, an ablation antenna device according to the present invention includes: a) an antenna including an inner conductor; and b) a conductive tip at the distal end of the antenna; wherein the inner conductor is not physically coupled to the conductive tip. The inner conductor is capacitively coupled to the conductive tip. The antenna includes a conductive outer conductor surrounding at least a portion of the inner conductor. The antenna includes a dielectric material between the inner and outer conductors. The antenna is a triaxial antenna. The conductive tip includes a trocar. The inner conductor includes a first region distal to a second region, the second region distal to a third region, wherein the third region is included in the triaxial antenna, wherein the second region is free of the triaxial antenna's outer conductor, and wherein the first region is free of the triaxial antenna's outer conductor and dielectric material. The first region is adhered to and surrounded by a metal fitting. The metal fitting is a brass metal fitting. The metal fitting extends distally beyond the distal end of the inner conductor. The metal fitting abuts the dielectric material surrounding the inner conductor in the second region. The second region includes a proximal portion containing the triaxial antenna's dielectric material and a distal portion free of the triaxial antenna's dielectric material. The distal portion of the second region includes a non-conductive sleeve surrounding the inner conductor. The non-conductive sleeve comprises PTFE. The conductive tip is attached to an insulator, which is attached to the distal end of the metal fitting. The insulator comprises a ceramic insulator. The metal fitting, the insulator, and the conductive tip are positioned and sized to create a low-impedance overlap, thereby transferring energy to the conductive tip when energy is supplied to the inner conductor. The metal fitting is adhered to the inner conductor via a conductive adhesive. The present invention also provides a system comprising the apparatus described above and a power source electrically connected to the apparatus. The system comprises the power source generating microwave energy. The system also comprises a coolant supply in fluid communication with the apparatus. The coolant supply comprises carbon dioxide. The antenna has a plug to prevent coolant from flowing to the distal end of the antenna. The system also comprises a control processor that regulates the delivery of energy and coolant from the power source to the antenna. The system also comprises one or more additional antennas. The present invention also provides a method of ablating a sample, comprising contacting the apparatus described above with a sample and supplying energy to the apparatus. The present invention also relates to the use of a device as described above for ablating a sample. Furthermore, the present invention provides a method for ablating a sample, comprising contacting an antenna as described above with a sample and providing energy to the device. The present invention also relates to the use of a system as described above for ablating a sample. In such methods or uses, the sample is a tissue sample. The tissue sample comprises a tumor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows a schematic diagram of an energy delivery system in one embodiment of the present invention.

FIG. 2 shows various shapes of coaxial transmission lines and/or dielectric components in some embodiments of the present invention.

3A and 3B illustrate a coaxial transmission line embodiment having segmented sections in which a first material and a second material are separated by a meltable wall for the purpose of preventing undesirable device heating (eg, heating along the outer conductor).

4A and 4B illustrate a coaxial transmission line embodiment having a partitioned segment separated by a meltable wall member, the partitioned segment housing a first material and a second material (e.g., materials configured to produce a temperature-reducing chemical reaction upon mixing) to prevent undesirable device heating (e.g., heating along the outer conductor).

FIG5 shows a schematic diagram of a handle configured to control the delivery of coolant into and out of the coolant passage.

FIG6 shows a schematic cross-sectional view of an embodiment of a coaxial cable having coolant channels.

7 shows a coolant circulation tube (eg, coolant needle, catheter) within an energy transmitting device having an outer conductor and a dielectric material.

FIG8 schematically illustrates the distal end of a device of the present invention (eg, an antenna of an ablation device) comprising a center-fed dipole assembly of the present invention.

Figure 9 shows the test facility and the locations of the temperature measurement stations. As shown in the figure, the ablation needle axis for all experiments was 20.5 cm. Probes 1, 2, and 3 were located 4, 8, and 12 cm from the tip of the stainless steel needle, respectively.

Figure 10 shows a treatment with an unusually high (6.5%) reflected power at 35% (microwaves "on" from 13:40 to 13:50).Probe 3 was initially placed in the air just outside the liver tissue.

Figure 11 shows a 10 minute treatment with an unusually high (6.5%) reflected power at 45% (microwaves on from 14:58 to 15:08). The peak temperature at station 4 was 40.25°C.

FIG. 12 shows a coaxial cable having a region of its outer conductor removed to create space for coolant flow, in one embodiment of the present invention.

Figure 13 shows a schematic diagram of the input/output box, transport sheath, and procedure device pod.

FIG. 14 shows an energy delivery device having two pull wires connected to a pull wire anchor.

15 shows an external perspective view of an energy delivery device having an inflexible region and a flexible region.

16 shows an energy delivery device having a narrow coaxial transmission line connected to a larger coaxial transmission line within the antenna, which is connected to the inner conductor.

17 shows a cross section of an energy delivery device having an inflexible region and a flexible region.

Figure 18 shows the procedure device hub connected to the procedure table strap.

Figure 19 shows a custom sterile drape with a fenestration and a cable inserted through the fenestration.

20 shows an energy delivery system of the present invention having a generator connected by a cable to a procedure device hub secured to a procedure table.

Figure 21 shows cooling via an energy delivery device. The temperature distribution measured 7 cm near the tip of the antenna during ablation demonstrates that cooling with chilled water can remove heating caused by input powers exceeding 120 W (top). Approximately 3 cm of ablation produced by cooling the antenna (125 W for 5 minutes) demonstrates the absence of a "tail" along the antenna. The ceramic tube and faceted tip enable percutaneous introduction (bottom).

Figure 22 shows the simulated temperature distribution along the antenna axis for various passive cooling techniques. The combination of thermal resistors and insulating sheaths reduces the proximal temperature most significantly.

Figure 23 shows a 10-minute microwave ablation (left) and radiofrequency ablation (right) in a normal porcine lung shown at equal scale. The microwave ablations are larger and more spherical than the radiofrequency ablations.

Figure 24 shows the experimental setup (top) and the resulting temperatures measured along the antenna axis when 35 W of heat was generated within the antenna axis (bottom). A _CO₂ flow rate of only 1.0 stp L/min was required to keep the temperature at any point along the axis from rising by more than 8°C. A flow rate of 10 stp L/min was sufficient to offset 50 W of heating power.

Figure 25 shows the experimental setup (top) and the temperature results (bottom) measured along the antenna axis when the antenna tip was maintained at 150°C for NC- _CO2 flow rates of 0, 13, and 23.8 stp L/min. It should be noted that heating only accounts for heat conduction from the antenna tip—internal heating was not considered in this test.

Figure 26 shows that a _CO2 pulse as small as 1 stp L/min lasting 10 seconds offsets the thermal conduction heating from the antenna tip.

Figure 27 shows the conventional image resolution and the highly constrained backprojection (HYPR) image resolution as a function of time.

FIG28 shows standard tumor images and highly constrained back-projected (HYPR) tumor images at some time periods.

FIG. 29 shows an embodiment of an energy delivery device.

FIG30 shows an embodiment of an energy delivery device.

FIG31 shows an embodiment of an energy delivery device within a procedure facility.

32A, B and C show examples of user interface software for the energy delivery system of the present invention.

FIG33 shows a three-axis microwave probe embodiment of the present invention.

34 shows ablated tissue created in ex vivo bovine tissue by A) a capacitively coupled antenna (eg, a precision probe) and B) an antenna without such coupling.

FIG35 summarizes in graphical format the average lateral ablation diameters achieved for a capacitively coupled antenna (eg, a precision probe) and an antenna without such coupling (for an input power of 30 Watts at various times).

FIG36 depicts the steps for coupling a precision probe to an existing antenna having an inner conductor, a dielectric, an outer conductor, and a trocar.

DETAILED DESCRIPTION

The present invention relates to comprehensive systems, devices, and methods for delivering energy (e.g., microwave energy, radiofrequency energy) to tissue for various applications, including medical procedures (e.g., tissue ablation, resection, electrocautery, vascular thrombosis, endoluminal ablation of hollow organs, cardiac ablation for arrhythmias, electrosurgery, tissue harvesting, cosmetic surgery, intraocular applications, etc.). In particular, the present invention provides systems for delivering microwave energy, comprising: a power source; a device for directing, controlling, and delivering power (e.g., a power divider); a processor; an energy-emitting device; a cooling system; an imaging system; a temperature monitoring system; and/or a tracking system. In certain embodiments, systems, devices, and methods for treating a tissue region (e.g., a tumor) using the energy delivery systems of the present invention are provided.

The systems of the present invention can be combined with various system/kit embodiments. For example, the present invention provides systems that include one or more of the following: a generator; a power distribution system; a device for directing, controlling, and delivering power (e.g., a power distributor); an energy applicator; and any one or more accessory components (e.g., surgical instruments, software supporting the procedure, a processor, a temperature monitoring device, etc.). The present invention is not limited to any particular accessory components.

The systems of the present invention can be used for any medical procedure (e.g., percutaneous or surgical) involving the delivery of energy (e.g., radiofrequency energy, microwave energy, laser, focused ultrasound, etc.) to a tissue region. The systems are not limited to treating a particular type or class of tissue regions (e.g., brain, liver, heart, blood vessels, foot, lung, bone, etc.). For example, the systems of the present invention are suitable for ablating tumor regions. Other treatments include, but are not limited to, treatment of cardiac arrhythmias, tumor ablation (benign and malignant), intraoperative bleeding control, post-traumatic bleeding, any other bleeding control, soft tissue removal, tissue resection and harvesting, varicose vein treatment, intracavitary tissue ablation (e.g., treatment of esophageal diseases such as Barth's esophagus and esophageal cancer), bone tumors, treatment of normal bone and benign bone conditions, intraocular applications, cosmetic surgical applications, treatment of central nervous system disorders including brain tumors and electrical disturbances, antiseptic procedures (e.g., ablation of the fallopian tubes), and cauterization of blood vessels or tissue for any purpose. In some embodiments, surgical applications include ablative treatments (e.g., to achieve coagulative necrosis). In some embodiments, surgical applications include tumor ablation of a target (e.g., a primary or metastatic tumor). In some embodiments, surgical applications include controlling bleeding (e.g., electrocautery). In some embodiments, surgical applications include cutting and removing tissue. In some embodiments, the device is configured to be moved and positioned in any desired location with minimal damage to tissues and organs, including, but not limited to, the brain, neck, chest, abdomen, pelvis, and lower extremities. In some embodiments, the device is configured for delivery guidance, such as by computed tomography, ultrasound imaging, magnetic resonance imaging, fluoroscopy, and the like.

The illustrative examples provided below describe the system of the present invention in the context of medical applications (e.g., ablating tissue by delivering microwave energy). However, it should be understood that the system of the present invention is not limited to medical applications. The system can be used in any facility requiring energy delivery to a load (e.g., agricultural facilities, manufacturing facilities, research facilities, etc.). The illustrated examples describe the system of the present invention in the context of microwave energy. It should be understood that the system of the present invention is not limited to a particular type of energy (e.g., radiofrequency energy, microwave energy, focused ultrasound energy, laser, plasma).

The systems of the present invention are not limited to any particular components or number of components. In some embodiments, the systems of the present invention include, but are not limited to, a power source, a device for directing, controlling, and delivering power (e.g., a power distributor), a processor, an energy delivery device with an antenna, a cooling system, an imaging system, and/or a tracking system. When multiple antennas are used, the system can be configured to independently control each antenna.

Figure 1 illustrates an exemplary system of the present invention. As shown, the energy delivery system includes a power source, transmission lines, power distribution components (e.g., a power splitter), a processor, an imaging system, a temperature monitoring system, and an energy delivery device. In some embodiments, as shown, the components of the energy delivery system are connected via transmission lines, cables, and the like. In some embodiments, the energy delivery device is separated from the power source, devices for directing, controlling, and delivering power (e.g., a power splitter), the processor, the imaging system, and the temperature monitoring system by a sterile field barrier.

Exemplary components of the energy delivery system are described in more detail in the following sections: I. Power Supply; II. Energy Delivery Device; III. Processor; IV. Imaging System; V. Tuning System; VI. Temperature Regulation System; VII. Identification System; VIII. Temperature Monitoring Device; IX. Programmer Hub; and X. Uses of the Energy Delivery System.

power supply

The energy used in the energy delivery systems of the present invention is supplied by a power supply. The present invention is not limited to a particular type or kind of power supply. In some embodiments, the power supply is configured to provide energy to one or more components of the energy delivery systems of the present invention (e.g., an ablation device). The power supply is not limited to providing a particular type of energy (e.g., radiofrequency energy, microwave energy, radiation energy, laser, focused ultrasound, etc.). The power supply is not limited to providing a particular amount of energy or providing energy at a particular delivery rate. In some embodiments, the power supply is configured to provide energy to an energy delivery device for the purpose of tissue ablation.

The present invention is not limited to a particular type of power source. In some embodiments, the power source is configured to provide any desired type of energy (e.g., microwave energy, radiofrequency energy, radiation, cold energy, electroporation, high-intensity focused ultrasound, and/or mixtures thereof). In some embodiments, the type of energy provided by the power source is microwave energy. In some embodiments, the power source provides microwave energy to an ablation device for the purpose of tissue ablation. The use of microwave energy for tissue ablation has many advantages. For example, microwaves have a wide power density (e.g., approximately 2 cm around the antenna, depending on the wavelength of the applied energy) and a correspondingly large active heating zone, allowing for uniform tissue ablation in the target and surrounding areas (see, e.g., International Application Publication No. WO 2006/004585; incorporated herein by reference in its entirety). Furthermore, microwave energy offers the ability to ablate large or multiple tissue regions using multiple probes with more rapid tissue heating. Microwave energy has the ability to penetrate tissue with less surface heating to create deep lesions. Energy delivery time is shorter than that of radiofrequency energy, and the probes can heat tissue sufficiently to create uniform and symmetrical lesions of predictable and controllable depth. Microwave energy is generally safe when used near blood vessels. Furthermore, microwaves do not rely on electrical conduction to radiate through tissue, fluids/blood, and air. Therefore, microwave energy can be used in tissue, lumens, lungs, and within blood vessels.

In some embodiments, the power supply includes one or more energy generators. In some embodiments, the generator is configured to provide microwave power up to 100 watts with a frequency from 915 MHz to 5.8 GHz, although the present invention is not limited thereto. In some embodiments, a conventional magnetron of the type commonly used in microwave ovens is selected as the generator. In some embodiments, a generator based on a single magnetron is used (e.g., with the ability to output 300W through a single channel or divided into multiple channels). However, it should be understood that any other suitable microwave power source can be used instead. In some embodiments, the type of generator includes but is not limited to the Sairem generator and the Gerling Applied Engineering generator available from Cober-Muegge, LLC, Norwalk, Connecticut, USA. In some embodiments, the generator has an available power of at least about 60 watts (e.g., 50, 55, 56, 57, 58, 59, 60, 61, 62, 65, 70, 100, 500, 1000 watts). For higher power operation, the generator can provide approximately 300 watts of power (e.g., 200, 280, 290, 300, 310, 320, 350, 400, 750 watts). In some embodiments using multiple antennas, the generator can provide more than 300 watts of power (e.g., 400, 500, 750, 1000, 2000, 10,000 watts). In some embodiments, multiple generators are used to provide power (e.g., three 140-watt amplifiers). In some embodiments, the generator includes solid-state amplifier modules that can operate individually and in a phased manner. In some embodiments, the outputs of the generators are constructively combined to increase the total output power. In some embodiments, the power supply uses a power distribution system to distribute energy (e.g., collected from the generators). The present invention is not limited to a particular power distribution system. In some embodiments, the power distribution system is configured to provide energy to an energy delivery device (e.g., a tissue ablation catheter) for tissue ablation purposes. The power distribution system is not limited to a specific method of collecting energy from, for example, the generators. The power distribution system is not limited to a specific method of providing energy to the ablation device. In some embodiments, the power distribution system is configured to transform the characteristic impedance of the generator so that it matches the characteristic impedance of the energy delivery device (eg, a tissue ablation catheter).

In some embodiments, the power distribution system is configured with a variable power splitter to provide different energy levels to different areas of an energy delivery device or to different energy delivery devices (e.g., tissue ablation catheters). In some embodiments, the power splitter is provided as a separate component of the system. In some embodiments, the power splitter is used to feed separate energy signals to multiple energy delivery devices. In some embodiments, the power splitter electrically isolates the energy delivered to each energy delivery device so that, for example, if one device experiences an increased load due to an increased temperature excursion, the energy delivered to that unit is modified (e.g., reduced, stopped), while the energy delivered to the backup device remains unchanged. The present invention is not limited to a particular type or class of power splitter. In some embodiments, the power splitter is designed by SM Electronics. In some embodiments, the power splitter is configured to receive energy from a power generator and provide energy to additional system components (e.g., energy delivery devices). In some embodiments, the power splitter can be connected to one or more additional system components (e.g., 1, 2, 3, 4, 5, 7, 10, 15, 20, 25, 50, 100, 500, etc.). In some embodiments, the power splitter is configured to provide variable amounts of energy to different regions within the energy delivery device to achieve the purpose of delivering variable amounts of energy from different regions of the device. In some embodiments, the power splitter is used to provide variable amounts of energy to multiple energy delivery devices to achieve the purpose of treating tissue regions. In some embodiments, the power splitter is configured to operate in a system that includes a processor, an energy delivery device, a temperature regulation system, a power splitter, a tuning system, and/or an imaging system. In some embodiments, the power splitter is capable of handling an increase in maximum generator output of, for example, 25% (e.g., 20%, 30%, 50%). In some embodiments, the power splitter is a 2-4 channel power splitter rated for 1000 watts.

In some embodiments employing multiple antennas, the systems of the present invention can be configured to operate simultaneously or sequentially (e.g., via switching). In some embodiments, the system is configured to phase control multiple regions of constructive or destructive interference. Phasing may also be applied to different elements within a single antenna. In some embodiments, switching is combined with phasing so that multiple antennas are activated simultaneously, phase controlled, and then switched to a new set of antennas (e.g., the switching need not be completely sequential). In some embodiments, phase control is achieved precisely. In some embodiments, the phase is continuously adjusted to move the region of constructive or destructive interference in space and time. In some embodiments, the phase is adjusted randomly. In some embodiments, the random phase adjustment is performed by mechanical interference and/or magnetic interference.

Energy delivery device

The energy delivery systems of the present invention contemplate use with any type of device (e.g., ablation device, surgical device, etc.) configured to deliver (e.g., emit) energy (see, e.g., U.S. Patent Nos. 7,101,369, 7,033,352, 6,893,436, 6,878,147, 6,823,218, 6,817,999, 6,635,055, 6,471,696, 6,383,182, 6,312,427, 6,287,302, 6,277,113, 6,251,128, 6,245,062, 6,026,331, 6,016,811, etc.). 0,803, 5,800,494, 5,788,692, 5,405,346, 4,494,539, U.S. Patent Application Serial Nos. 11/728,460, 11/728,457, 11/728,428, 11/237,136, 11/236,985, 10/980,699, 10/961,994, 10/961,761, 10/834,802, 10/370,179, 09/847,181; U.K. Patent Application Nos. 2,406,521, 2,388,039; European Patent No. 1395190; and International Patent Application No. WO 06/008481, WO 06/002943, WO 05/034783, WO 04/112628, WO 04/033039, WO 04/026122, WO 03/088858, WO 03/039385, WO 95/04385; each of which is incorporated herein by reference in its entirety). Such devices include any and all medical, veterinary, and research applications configured for energy emission, as well as devices used in agricultural settings, manufacturing settings, machinery, or any other application where energy is to be delivered.

In some embodiments, the system utilizes an energy delivery device having an antenna therein that is configured to transmit energy (e.g., microwave energy, radiofrequency energy, radiant energy). The system is not limited to a particular type or design of antenna (e.g., ablation device, surgical device, etc.). In some embodiments, the system utilizes an energy delivery device having an antenna having a linear shape (see, e.g., U.S. Patent Nos. 6,878,147, 4,494,539, U.S. Patent Application Serial Nos. 11/728,460, 11/728,457, 11/728,428, 10/961,994, 10/961,761; and International Patent Application No. WO 03/039385; each of which is incorporated herein by reference in its entirety). In some embodiments, the system utilizes an energy delivery device having an antenna with a nonlinear shape (see, e.g., U.S. Patent Nos. 6,251,128, 6,016,811, and 5,800,494, U.S. Patent Application Serial No. 09/847,181, and International Patent Application No. WO 03/088858; each of which is incorporated herein by reference in its entirety). In some embodiments, the antenna has a corner reflective component (see, e.g., U.S. Patent Nos. 6,527,768 and 6,287,302; each of which is incorporated herein by reference in its entirety). In certain embodiments, the antenna has a directional reflector (see, e.g., U.S. Patent No. 6,312,427; incorporated herein by reference in its entirety). In some embodiments, the antenna has a fixation component to secure the energy delivery device to a specific tissue region (see, e.g., U.S. Patent Nos. 6,364,876 and 5,741,249; each of which is incorporated herein by reference in its entirety).

Generally, the antenna configured to transmit energy includes a coaxial transmission line. The apparatus is not limited to a particular configuration of the coaxial transmission line. Examples of coaxial transmission lines include, but are not limited to, those developed by Pasternack, Micro-coax, and SRCCables. In some embodiments, the coaxial transmission line has a center conductor, a dielectric element, and an outer conductor (e.g., an outer shield). In some embodiments, the system utilizes an antenna having a flexible coaxial transmission line (e.g., for positioning around, for example, a pulmonary vein or through a tubular structure) (see, e.g., U.S. Patent Nos. 7,033,352, 6,893,436, 6,817,999, 6,251,128, 5,810,803, 5,800,494; each of which is incorporated herein by reference in its entirety). In some embodiments, the system utilizes an antenna with a rigid coaxial transmission line (see, eg, US Patent No. 6,878,147, US Patent Application Serial Nos. 10/961,994 and 10/961,761, and International Patent Application Nos. WO and 03/039385; each incorporated herein by reference in its entirety).

In some embodiments, the energy delivery device includes a coaxial transmission line within the antenna and a coaxial transmission line connected to the antenna. In some embodiments, the coaxial transmission line within the antenna is larger than the coaxial transmission line connected to the antenna. The coaxial transmission line within the antenna and the coaxial transmission line connected to the antenna are not limited to a particular size. For example, in some embodiments, the coaxial transmission line connected to the antenna is approximately 0.032 inches, while the coaxial transmission line within the antenna is larger than 0.032 inches (e.g., 0.05 inches, 0.075 inches, 0.1 inches, 0.5 inches). In some embodiments, the coaxial transmission line within the antenna has a stiff and thick inner conductor. In some embodiments, the end of the coaxial transmission line within the antenna is sharpened for percutaneous use. In some embodiments, the dielectric coating of the coaxial transmission line within the antenna is polytetrafluoroethylene (PTFE) (e.g., to smooth the transition from the sheath to the inner conductor (e.g., a thin, sharp inner conductor)). 16 shows an energy delivery device 1600 having a narrow coaxial transmission line 1610 connected to a larger coaxial transmission line 1620 located within an antenna 1630, which is connected to an inner conductor 1640.

The present invention is not limited to a particular coaxial transmission line shape. In fact, in some embodiments, the shape of the coaxial transmission line and/or dielectric element is selected and/or adjustable to suit specific needs. FIG2 illustrates some different non-limiting shapes that the coaxial transmission line and/or dielectric element can assume.

In some embodiments, the outer conductor is a 20-gauge needle or an assembly having a diameter similar to a 20-gauge needle. Preferably, for percutaneous use, the outer conductor is no larger than a 17-gauge needle (e.g., no larger than a 16-gauge needle). In some embodiments, the outer conductor is a 17-gauge needle. However, in some embodiments, a larger device is used as needed. For example, in some embodiments, a 12-gauge needle is used. The present invention is not limited to the size of the outer conductor. In some embodiments, the outer conductor is configured to fit within a series of larger needles for use in assisting medical procedures (e.g., assisting in tissue biopsies) (see, e.g., U.S. Patent Nos. 6,652,520, 6,582,486, 6,355,033, and 6,306,132; each of which is incorporated herein by reference in its entirety). In some embodiments, the center conductor is configured to extend beyond the outer conductor to facilitate delivery of energy to a desired location. In some embodiments, the characteristic impedance of some or all feed lines is optimized to minimize power consumption, regardless of the type of antenna terminating at their distal end.

In some embodiments, an energy delivery device is provided having a proximal portion and a distal portion, wherein the distal portion is detachable and provided in a variety of different configurations that can be attached to a core proximal portion. For example, in some embodiments, the proximal portion includes a handle and an interface to other components of the system (e.g., a power source), and the distal portion includes a detachable antenna having desired characteristics. A plurality of different antennas configured for different purposes are provided and attached to the handle unit for appropriate indication.

In some embodiments, multiple (e.g., more than one) (e.g., 2, 3, 4, 5, 10, 20, etc.) coaxial transmission lines and/or triaxial transmission lines are located within each energy delivery device to deliver a large amount of energy over an extended period of time. In experiments conducted during the development of embodiments of the present invention, it was determined that an energy delivery device having three low-power coaxial transmission lines (e.g., located within the same probe) (e.g., within a 13-gauge needle) was able to deliver a greater amount of energy over a longer period of time than an energy delivery device having a higher-power coaxial transmission line.

In some embodiments, the energy delivery device includes a triaxial microwave probe with optimized tuning capabilities (see, e.g., U.S. Patent No. 7,101,369; see also U.S. Patent Application Nos. 10/834,802, 11/236,985, 11/237,136, 11,237,430, 11/440,331, 11/452,637, 11/502,783, 11/514,628, and International Patent Application No. PCT/US05/14534; incorporated herein by reference in their entireties). The triaxial microwave probe is not limited to a particular optimized tuning capability. In some embodiments, the triaxial microwave probe has predefined optimized tuning capabilities specific to a particular tissue type. FIG33 shows a triaxial microwave probe 33000 having a first conductor 33100, a second conductor 33200 coaxially surrounding but insulated from first conductor 33100, and a tubular third conductor 33300 coaxially surrounding first and second conductors 33100 and 33200. In some embodiments, first conductor 33100 is configured to extend beyond second conductor 33200 into tissue, for example, when the distal end of triaxial microwave probe 33000 is inserted into the body for microwave ablation. As shown in FIG33 , the distance first conductor 33100 extends from second conductor 33200 is effective length 33400. In some embodiments, second conductor 33200 is configured to extend beyond third conductor 33300 into tissue. As shown in FIG33 , the distance second conductor 33200 extends from third conductor 33300 is insertion depth 33500. Experiments conducted during the development of embodiments of the present invention determined optimal insertion depth and effective length measurements for specific tissue types. For example, using a triaxial microwave probe as shown in FIG33 and lung tissue, the optimal insertion depth is 3.6 mm, and the optimal effective length is 16 mm. For example, using a triaxial microwave probe as shown in FIG33 and liver tissue, the optimal insertion depth is 3.6 mm, and the optimal effective length is 15 mm. For example, using a triaxial microwave probe as shown in FIG33 and kidney tissue, the optimal insertion depth is 3.6 mm, and the optimal effective length is 15 mm. In some embodiments, the triaxial microwave probe is configured to ablate smaller tissue areas (e.g., ablating only the edges of an organ, ablating small tumors, etc.). In such embodiments, the length of the first conductor is reduced (e.g., so that the wire contacts the tip of the conductor to maintain a small ablation zone).

In some embodiments, the devices of the present invention are configured to attach to a detachable handle. The present invention is not limited to a particular type of detachable handle. In some embodiments, the detachable handle is configured to connect to multiple devices (e.g., 1, 2, 3, 4, 5, 10, 20, 50, ...) to control energy delivery via such devices. In some embodiments, the handle is designed to include a power amplifier to provide power to the energy delivery device.

In some embodiments, the device is designed to physically surround a specific tissue region for the purpose of energy delivery (e.g., the device can be flexibly shaped to encompass a specific tissue region). For example, in some embodiments, the device can be flexibly shaped to encompass a blood vessel (e.g., a pulmonary vein) for the purpose of delivering energy to a precise region within tissue.

In some embodiments, the energy delivery device is configured to maintain its shape when exposed to compressive pressure. The energy delivery device is not limited to a specific configuration for maintaining its shape when exposed to compressive pressure. In some embodiments, the energy delivery device includes a pull wire system for maintaining its shape when compressed. The present invention is not limited to a specific type of pull wire system. In some embodiments, the pull wire system includes one or more pull wires (e.g., one pull wire, two pull wires, five pull wires, ten pull wires, or fifty pull wires) connected to a pull wire anchor. In some embodiments, contracting (e.g., pushing, pulling) one or more pull wires connected to the pull wire anchor (e.g., by a user) causes the energy delivery device to assume a non-flexible state, allowing the energy delivery device to maintain its shape when exposed to compressive pressure. In some embodiments, the pull wires can be locked in a contracted position. In some embodiments, an energy delivery device having one or more pull wires connected to a pull wire anchor remains flexible even without the pull wires contracting. FIG. 14 shows an energy delivery device 1400 having two pull wires 1410 and 1420 connected to a pull wire anchor 1430. In some embodiments, the energy delivery device has three or more drawwires arranged in a symmetrical pattern that are prestressed to provide a constant, non-flexible shape. In some embodiments, the drawwires are configured to automatically contract (e.g., myofilaments) in response to a stimulus (e.g., electrical stimulation, compressive stimulation). In some embodiments, the drawwires are configured to provide a balancing force (e.g., a counterforce) in response to a compressive force. In some embodiments, the drawwires are designed to bend at a specific temperature (e.g., superelastic nickel-titanium wire). In some embodiments, bending of the drawwires at a specific temperature is a detectable event that can be used to monitor the status of the procedure.

In some embodiments, the energy delivery device is configured with a flexible region and an inflexible region. The energy delivery device is not limited to a particular configuration having flexible and inflexible regions. In some embodiments, the flexible region comprises plastic (e.g., PEEK). In some embodiments, the inflexible region comprises ceramic. The flexible and inflexible regions are not limited to specific locations within the energy delivery device. In some embodiments, the flexible region is located in an area experiencing lower levels of microwave field emission. In some embodiments, the inflexible region is located in an area experiencing higher levels of microwave field emission (e.g., above the proximal portion of the antenna to provide dielectric strength and mechanical rigidity). FIG15 shows an external perspective view of an energy delivery device 1500 having inflexible regions 1510 and 1520 (e.g., ceramic) and a flexible region 1530 (e.g., PEEK). FIG17 shows a cross-section of an energy delivery device 1700 having inflexible regions 1710 and 1720 and a flexible region 1730. As shown, inflexible zones 1710 and 1720 taper gradually to provide a larger surface area, for example, for bonding with a cannula, and thereby distribute stress from bending forces over a larger surface area. As shown, flexible zone 1730 is located on the outer side of the connector to increase strength due to its large diameter. In some embodiments, the gradual taper of the inflexible zone is filled with bonding material to provide additional strength. In some embodiments, the energy delivery device includes heat shrink on the distal portion (e.g., the antenna) to provide additional durability.

In some embodiments, the material of the antenna is durable and provides a high dielectric constant. In some embodiments, the material of the antenna is zirconium or a functional equivalent of zirconium. In some embodiments, the energy delivery device is provided as two or more independent antennas attached to the same or different power sources. In some embodiments, the different antennas are connected to the same handle, while in other embodiments, a different handle is provided for each antenna. In some embodiments, multiple antennas are used within the patient's body simultaneously or sequentially (e.g., switching) to deliver energy with a desired intensity and geometry within the patient's body. In some embodiments, the antennas are individually controllable. In some embodiments, the multiple antennas can be operated by a single user, by a computer, or by multiple users.

In some embodiments, the energy delivery device is designed to operate within a sterile field. The present invention is not limited to a specific sterile field setup. In some embodiments, the sterile field includes the area surrounding the subject (e.g., an operating table). In some embodiments, the sterile field includes any area where only sterilized items (e.g., sterilization equipment, disinfection aids, sterilized body parts) are permitted to remain. In some embodiments, the sterile field includes any area susceptible to infection by pathogens. In some embodiments, the sterile field includes a sterile field barrier that establishes a barrier between the sterile field and a non-sterile field. The present invention is not limited to a specific sterile field barrier. In some embodiments, the sterile field barrier is a drape surrounding the subject undergoing a procedure (e.g., tissue ablation) involving the system of the present invention. In some embodiments, the room is sterile and provides the sterile field. In some embodiments, the sterile field barrier is established by a user of the system of the present invention (e.g., a physician). In some embodiments, the sterile field barrier prevents non-sterile items from entering the sterile field. In some embodiments, the energy delivery device is provided within the sterile field, while one or more other components of the system (e.g., a power source) are not contained within the sterile field.

In some embodiments, the energy delivery device includes a protection sensor designed to prevent unwanted use of the energy delivery device. Energy delivery devices are not limited to a particular type or class of protection sensors. In some embodiments, the energy delivery device includes a temperature sensor designed to measure, for example, the temperature of the energy delivery device and/or tissue contacting the energy delivery device. In some embodiments, when the temperature reaches a certain level, the sensor sends a warning to the user, for example, via a processor. In some embodiments, the energy delivery device includes a skin contact sensor designed to detect contact between the energy delivery device and the skin (e.g., the outer surface of the skin). In some embodiments, when unwanted skin contact occurs, the skin contact sensor sends a warning to the user, for example, via a processor. In some embodiments, the energy delivery device includes an air contact sensor designed to detect contact between the energy delivery device and ambient air (e.g., by measuring reflected electrical power passing through the device). In some embodiments, when unwanted air contact occurs, the skin contact sensor sends a warning to the user, for example, via a processor. In some embodiments, these sensors are designed to prevent use of the energy delivery device (e.g., by automatically reducing or preventing power delivery) upon detecting the occurrence of an unwanted event (e.g., contact with skin, contact with air, or an unwanted temperature increase or decrease). In some embodiments, the sensors communicate with the processor so that the processor displays an indication (e.g., a green light) when no undesirable event has occurred. In some embodiments, the sensors communicate with the processor so that the processor displays an indication (e.g., a red light) when an undesirable event has occurred and confirms the occurrence of the undesirable event.

In some embodiments, the energy delivery device is used at a power rating above the manufacturer's recommended power rating. In some embodiments, the cooling techniques described herein are used to enable higher power delivery. The present invention is not limited to a particular power increase. In some embodiments, the power rating exceeds the manufacturer's recommended power rating by a factor of 5 or more (e.g., 5 times, 6 times, 10 times, 15 times, 20 times, etc.).

Furthermore, the devices of the present invention are configured to deliver energy from different regions of the device (e.g., the gaps between outer conductor segments, described in more detail below) at different times (e.g., controlled by the user) and at different energy intensities (e.g., controlled by the user). This control of the device allows for phase control of the energy transmission field to achieve constructive phase interference at specific tissue regions or destructive phase interference at specific tissue regions. For example, a user can utilize energy delivery through two (or more) closely positioned outer conductor segments to achieve combined energy intensities (e.g., constructive phase interference). This combined energy intensity may be particularly useful in deep or dense tissue regions. Furthermore, this combined energy intensity can be achieved by using two (or more) devices. In some embodiments, phase interference (e.g., constructive phase interference, destructive phase interference) between one or more devices is controlled by a processor, tuning elements, the user, and/or a power splitter. Thus, the user can control the energy release through different regions of the device and the amount of energy delivered to each region of the device, thereby precisely shaping the ablation zone.

In some embodiments, the energy delivery systems of the present invention utilize energy delivery devices with optimized characteristic impedance, energy delivery devices with cooling channels, energy delivery devices with center-fed dipoles, and energy delivery devices with linear arrays of antenna assemblies (each described in more detail above and below).

As described in the Summary of the Invention section above, the present invention provides various methods for cooling the device. Some embodiments utilize a fusible shield that, when melted, allows chemicals to come into contact, resulting in an endothermic reaction. An example of such an embodiment is illustrated in FIG3 . FIG3A and FIG3B illustrate a coaxial transmission line region (e.g., a channel) having segmented sections having first and second materials separated by a fusible wall to prevent undesirable device heating (e.g., heating along the outer conductor). FIG3A and FIG3B depict a standard coaxial transmission line 300 configured for use in any of the energy delivery devices of the present invention. As shown in FIG3A , coaxial transmission line 300 has a center conductor 310, a dielectric material 320, and an outer conductor 330. Furthermore, coaxial transmission line 300 has four segments 340 separated by walls 350 (e.g., fusible wax walls). Segments 340 are divided into a first segment 360 and a second segment 370. In some embodiments, as shown in FIG3A , first segments 360 and second segments 370 are sequentially interleaved. As shown in FIG3A , first segment 360 contains a first material (shaded type one) and second segment 370 contains a second material (shaded type two). Wall members 350 prevent the first and second materials from mixing. FIG3B shows the coaxial transmission line 300 shown in FIG3A after an event (e.g., a temperature increase at one of the segments 340) has occurred. As shown, one of the wall members 350 has melted, allowing the first material contained in region 360 and the second material contained in region 370 to mix. FIG3B further illustrates unmelted wall 350, where the temperature increase does not exceed a certain temperature threshold.

FIG4 illustrates an alternative embodiment. FIG4A and FIG4B illustrate a coaxial transmission line embodiment having segments separated by meltable walls, wherein the segments comprise first and second materials (e.g., materials configured to undergo a temperature-reducing chemical reaction upon mixing) to prevent undesirable device heating (e.g., heating along the outer conductor). FIG4A and FIG4B illustrate a coaxial transmission line 400 configured for use in any of the energy delivery devices of the present invention. As shown in FIG4A , coaxial transmission line 400 comprises a center conductor 410, a dielectric material 420, and an outer conductor 430. Furthermore, coaxial transmission line 400 comprises four segments 440 separated by walls 450. Each wall 450 comprises a first material 460 separated from a second material 470. FIG4B illustrates the coaxial transmission line 400 shown in FIG4A after an event (e.g., an increase in temperature at one of the segments 440) has occurred. As shown, one of the walls 450 has melted, allowing the first material 460 and the second material 470 within an adjacent segment 440 to mix. FIG. 4B further illustrates an unmelted wall 450 where the temperature increase does not rise above a certain temperature threshold.

In some embodiments, the device further includes an anchoring element for securing the antenna to a specific tissue region. The device is not limited to a particular type of anchoring element. In some embodiments, the anchoring element is an inflatable balloon (e.g., inflation of the balloon secures the antenna to a specific tissue region). An additional advantage of using an inflatable balloon as an anchoring element is that blood or air flow is restricted to a specific region upon inflation. This restriction of air or blood flow is particularly useful in, for example, cardiac ablation procedures and ablation procedures involving lung tissue, vascular tissue, and gastrointestinal tissue. In some embodiments, the anchoring element is an extension of the antenna designed to engage (e.g., lock onto) a specific tissue region. Further examples include, but are not limited to, the anchoring elements described in U.S. Patent Nos. 6,364,876 and 5,741,249; each of which is incorporated herein by reference in its entirety. In some embodiments, the anchoring element comprises a circulating agent (e.g., a gas delivered at or near its critical point; e.g., _CO2 ) that freezes the interface between the antenna and the tissue, thereby securing the antenna in place. In such an embodiment, as the tissue melts, the antenna remains secured to the tissue region due to tissue desiccation.

Thus, in some embodiments, the device of the present invention is used to ablate tissue regions with large amounts of airflow and/or blood flow (e.g., lung tissue, cardiac tissue, gastrointestinal tissue, vascular tissue). In some embodiments involving ablation of tissue regions with large amounts of airflow and/or blood flow, an element is further utilized to inhibit the flow of air and/or blood to the tissue region. The present invention is not limited to a specific airflow and/or blood flow inhibition element. In some embodiments, the device is combined with a tracheal/bronchial tube. In some embodiments, a balloon attached to the device can be inflated at the tissue region to secure the device within the desired tissue region and inhibit the flow of blood and/or air to the desired tissue region.

Thus, in some embodiments, the systems, devices, and methods of the present invention provide a combination that provides an ablation device coupled to a component that provides passageway occlusion (e.g., bronchial occlusion). The occlusion component (e.g., an inflatable balloon) can be mounted directly on the ablation system, or can be used in conjunction with another component associated with the system (e.g., a tracheal or endobronchial tube). In some embodiments, the device of the present invention can be mounted on an additional medical procedure device. For example, the device can be mounted on an endoscope, an intravascular catheter, or a laparoscope. In some embodiments, the device is mounted on a steerable catheter. In some embodiments, a flexible catheter is mounted on an endoscope, an intravascular catheter, or a laparoscope. For example, in some embodiments, the flexible catheter has multiple joints that allow it to bend and steer as needed (e.g., like a centipede) to navigate to the desired treatment location.

In some embodiments, the energy delivery device includes a plug region designed to isolate internal portions of the energy delivery device, for example, to prevent cooling or heating of one or more portions of the device while allowing cooling or heating of other portions. The plug region can be configured to separate any desired region or regions of the energy delivery device from any other region. In some embodiments, the plug region is designed to prevent cooling of one or more regions of the energy delivery device. In some embodiments, the plug region is designed to prevent cooling of a portion of the energy delivery device configured to provide ablative energy. The plug region is not limited to a particular method for preventing cooling of a portion of the device. In some embodiments, the plug region is designed to contact a region with a reduced temperature (e.g., a region of the energy delivery device where a coolant circulates). In some embodiments, the plug region is made of a material that allows it to contact a material or region with a reduced temperature without significantly reducing its own temperature (e.g., an insulating material). The plug region is not limited to a specific type of insulating material (e.g., synthetic polymers (e.g., polystyrene, condensate, polyurethane, polyisocyanurate), aerogel, fiberglass, cork). The plug region is not limited to a specific size. In some embodiments, the plug region is sized to prevent the cooling effect of the circulating coolant from lowering the temperature of other areas of the energy delivery device. In some embodiments, the plug region is positioned along the entire cannula portion of the energy delivery device. In some embodiments, the plug region is located at a distal portion of the cannula portion of the energy delivery device. In some embodiments, the plug region surrounds the exterior of the cannula portion of the energy delivery device.

In some embodiments, an energy delivery device includes a "bonding" region designed to secure the energy delivery device to a tissue region. The bonding region is not limited to a particular method for facilitating association of the energy delivery device with the tissue region. In some embodiments, the bonding region is configured to reach and maintain a reduced temperature such that, upon contact with the tissue region, the tissue region adheres to the bonding region, thereby attaching the energy delivery device to the tissue region. The bonding region is not limited to a specific material composition. In some embodiments, the bonding region is, for example, a metal, a ceramic, a plastic, and/or any combination thereof. In some embodiments, the bonding region comprises any material capable of reaching and maintaining a temperature such that, upon contact with the tissue region, the tissue region adheres to the bonding region. The bonding region is not limited to a specific size. In some embodiments, the bonding region is sized to maintain adhesion to the tissue region during simultaneous tissue ablation and/or simultaneous movement (e.g., positioning) of the energy delivery device. In some embodiments, two or more bonding regions are provided. In some embodiments, the bonding region is protected from exposure to the distal region of the device by a seal. In some embodiments, the seal is positioned between the bonding region and the distal region of the device, thereby protecting the bonding region from exposure to the distal region. In some embodiments, the seal is configured as an air/gas seal. In some embodiments, the seal is laser welded to the device (e.g., the coaxial region). In some embodiments, the seal is induction brazed to the device (e.g., the coaxial region). In some embodiments, the seal is partially (e.g., 60%/40%; 55%/45%; 50%/50%) laser welded and induction brazed.

FIG29 shows an embodiment of an energy delivery device of the present invention. As shown, the energy delivery device 100 is positioned near the ablation zone 105. As shown, the energy delivery device 100 has a cooling tube 110 and a cable assembly 120 connected to a handle 130, which is connected to a cooling probe cannula 140, which is connected to an antenna area 150. As shown, the area between the cooling probe cannula 140 and the antenna area 150 has a bonding area 160 and a plug area 170. The bonding area 160 is designed to reach and maintain a temperature suitable for adhering a tissue area to its surface. The plug area 170 is designed to prevent the temperature from being reduced by the cooling probe cannula 140 and to prevent the bonding area 160 from affecting (e.g., reducing) the temperature within the antenna area 150. As shown, in these embodiments, the ablation zone 105 includes cooled areas of the energy delivery device 100 (eg, cooled probe sheath 140 and bonding area 160 ) and uncooled areas of the energy delivery device 100 (eg, plug area 170 and antenna area 150 ).

Energy delivery device with optimized characteristic impedance

In some embodiments, the energy delivery systems of the present invention utilize devices configured to deliver microwave energy having an optimized characteristic impedance (see, e.g., U.S. patent application Ser. No. 11/728,428; incorporated herein by reference in its entirety). Such devices are configured to operate with a characteristic impedance greater than 50Ω (e.g., between 50 and 90Ω; e.g., greater than 50, ... 55, 56, 57, 59, 58, 60, 61, 62, ... 90Ω, preferably 77Ω).

Energy delivery devices configured to operate with an optimized characteristic impedance are particularly useful in tissue ablation procedures and offer numerous advantages over non-optimized devices. For example, a major drawback of currently available medical devices utilizing microwave energy is the undesirable dissipation of energy through the transmission line into the subject's tissue, which can lead to undesirable burns. This microwave energy loss stems from design limitations of currently available medical devices. The standard impedance of coaxial transmission lines within medical devices is 50Ω or less. Generally, coaxial transmission lines with impedances below 50Ω experience significant heat losses due to the presence of dielectric materials with finite electrical conductivity. Consequently, medical devices incorporating coaxial transmission lines with impedances of 50Ω or less experience significant heat losses along the transmission line. In particular, medical devices utilizing microwave energy transmit energy through a coaxial cable containing a dielectric material (e.g., polytetrafluoroethylene, or PTFE) surrounding the inner conductor. Dielectric materials such as PTFE have limited electrical conductivity, leading to undesirable heating of the transmission line. This is particularly true when delivering the necessary amount of energy over a sufficient period of time to achieve tissue ablation. Energy delivery devices configured to operate with an optimized characteristic impedance overcome this limitation by being free of, or substantially free of, solid dielectric insulators. For example, replacing a conventional dielectric insulator with air results in an effective device operating at an impedance of 77Ω. In some embodiments, the device employs a dielectric material with near-zero conductivity (e.g., water, air, an inert gas, a vacuum, a partial vacuum, or a combination thereof). By using a coaxial transmission line with a dielectric material having near-zero conductivity, the overall temperature of the transmission line in such a device is significantly reduced, thereby significantly reducing undesirable tissue heating.

Furthermore, by providing a coaxial transmission line with a dielectric material having near-zero conductivity and avoiding the use of typical dielectric polymers, the coaxial transmission line can be designed so that it can fit within a small needle (e.g., an 18–20 gauge needle). Typically, medical devices configured to deliver microwave energy are fitted within large needles due to the bulk of the dielectric material. Microwave ablation has not been widely used clinically due to the large size of the probe (14 gauge) and the relatively small necrotic area (1.6 cm in diameter) (Seki T et al., Cancer 74:817 (1994)) produced by the only commercial device (Microtaze, Nippon Shoji Co., Ltd., Osaka, Japan. 2.450 MHz, 1.6 mm diameter probe, 70 W power for 60 seconds). Other devices use a cooling external water jacket, which also increases the size of the probe and may increase tissue damage. These large probe sizes increase the risk of complications when used in the chest and abdomen.

Energy delivery device with coolant delivery channel

In some embodiments, the energy delivery systems of the present invention utilize energy delivery devices with coolant delivery channels (see, for example, U.S. Patent No. 6,461,351 and U.S. Patent Application Serial No. 11/728,460; incorporated herein by reference in their entireties). Specifically, the energy delivery systems of the present invention employ devices having coaxial transmission lines that allow for cooling by flowing a cooling material through the dielectric and/or inner or outer conductors of the coaxial assembly. In some embodiments, the device is configured to minimize the device diameter while allowing for coolant delivery. In some embodiments, this is achieved by replacing multiple sections of the inner or outer conductor and/or solid dielectric material with channels through which the coolant is transferred. In some embodiments, these channels are created by stripping the outer or inner conductor and/or solid dielectric material from one or more (e.g., two, three, four) regions along the length of the coaxial cable. When the removed portions of the outer or inner conductor and/or solid dielectric material create channels for coolant transfer, the stripped assembly fits within a smaller outer conductor than before the outer or inner conductor and/or solid dielectric material was removed. This provides for a smaller device and all the advantages that flow therefrom. In some embodiments employing multiple channels, coolant transfer can be through one or more channels in alternating directions. An advantage of such a device is that the diameter of the coaxial cable does not need to be increased to accommodate the coolant. This allows for the use of minimally invasive cooling devices that allow access to areas of the body that would otherwise be inaccessible or accessible only at undesirable risk. The use of coolant also allows for greater energy delivery and/or energy delivery over a longer period of time. Additional cooling embodiments are described above in the Summary of the Invention.

In some embodiments, the device has a handle attached to the device, wherein the handle is configured to, for example, control the flow of coolant into and out of the coolant channels. In some embodiments, the handle automatically flows coolant into and out of the coolant channels after a certain amount of time and/or after the device reaches a certain threshold temperature. In some embodiments, the handle automatically stops flowing coolant into and out of the coolant channels after a certain amount of time and/or after the temperature of the device drops below a certain threshold temperature. In some embodiments, the handle is manually controlled to adjust the flow of coolant.

In some embodiments, the handle has one or more (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) lights (e.g., display lights (e.g., LED lights)). In some embodiments, the lights are configured for identification purposes. For example, in some embodiments, the lights indicate whether a particular function of the device is active or inactive. For example, if the device has multiple probes, one or more lights indicate whether any individual probe is powered on or off. In some embodiments, the lights are used to identify the occurrence of an event (e.g., the delivery of coolant through the device, the delivery of energy through the device, movement of individual probes, changes in a set value within the device (e.g., temperature, position), etc.). The handle is not limited to a particular display mode (e.g., flashing, alternating colors, solid color, etc.). FIG. 30 shows a device 30000 having three LED lights 31000, 32000, and 33000. FIG. 31 shows such a device 30000 in use, wherein the device has three LED lights 31000, 32000, and 33000.

FIG5 shows a schematic diagram of a handle configured to control the delivery and removal of coolant into and out of a coolant channel. As shown in FIG5 , handle 500 is coupled to a coaxial transmission line 510 having a coolant channel 520. Handle 500 includes a coolant input channel 530, a coolant output channel 540, a first blocking assembly 550, and a second blocking assembly 560. The first blocking assembly 550 (e.g., a screw or latch) is configured to prevent flow through channel 520 behind the blocking assembly. Coolant input channel 530 is configured to supply coolant to coolant channel 520. Coolant output channel 540 is configured to remove coolant (e.g., coolant that has already circulated and removed heat from the device) from coolant channel 520. Coolant input channel 530 and coolant output channel 540 are not limited to any particular size or means for supplying and removing coolant. The first blocking assembly 550 and the second blocking assembly 560 are not limited to any particular shape or size. In some embodiments, the first and second blocking assemblies 550, 560 each have a circular shape and dimensions that match the diameters of the coolant input channel 530 and the coolant output channel 540. In some embodiments, the first and second blocking assemblies 550, 560 are used to block coolant from flowing back into a certain area of the handle 500. In some embodiments, the blocking assemblies are configured so that only a portion (e.g., 1%, 5%, 10%, 20%, 50%, 75%, 85%, 95%, or 99%) of the channel is blocked. Blocking only a portion allows, for example, a user to alter the pressure gradient within the coolant channel.

Energy delivery devices with coolant delivery channels allow for adjustment of the characteristic impedance of a coaxial transmission line. Specifically, the dielectric properties of the coolant (or non-coolant material passing through the channels) can be adjusted to alter the overall composite dielectric constant of the dielectric medium separating the outer and inner conductors. Thus, changes in characteristic impedance can be made during a procedure to, for example, optimize energy delivery, tissue effects, temperature, or other desired properties of a system, device, or application. In other embodiments, a flowing material is selected prior to the procedure based on desired parameters and maintained throughout the procedure. Thus, such devices provide antennas that radiate in varying dielectric environments and can be adjusted to resonate in these varying environments, allowing, for example, adaptive tuning of the antenna to ensure peak operational efficiency. Fluid flow also allows for heat transfer to and from the coaxial cable as needed. In some embodiments, the channels or hollowed-out areas contain a vacuum or partial vacuum. In some embodiments, the impedance is altered by filling the vacuum with a material (e.g., any material that provides the desired results). Adjustments can be made at one or more points in time or continuously.

Energy delivery devices having coolant transfer channels are not limited to specific aspects of the channels. In some embodiments, the channel only cuts through a portion of the outer conductor or inner conductor and/or solid dielectric material, so that the flowing material contacts the outer conductor or inner conductor and the remaining dielectric material. In some embodiments, the channel is linear along the length of the coaxial cable. In some embodiments, the channel is non-linear. In some embodiments using multiple channels, the channels are arranged parallel to each other. In other embodiments, the channels are non-parallel. In some embodiments, the channels intersect with each other. In some embodiments, the channel removes more than 50% (e.g., 60%, 70%, 80%, etc.) of the outer conductor or inner conductor and/or solid dielectric material. In some embodiments, the channel removes substantially all of the outer conductor or inner conductor and/or solid dielectric material.

Energy delivery devices having coolant transfer channels are not limited by the properties of the material flowing through the outer or inner conductor and/or solid dielectric material. In some embodiments, the material is selected to maximize the ability to control the characteristic impedance of the device, maximize heat transfer to or from the coaxial cable, or optimize a combination of controlling characteristic impedance and heat transfer. In some embodiments, the material flowing through the outer or inner conductor and/or solid dielectric material is a liquid. In some embodiments, the material is a gas. In some embodiments, the material is a combination of a liquid or a gas. The present invention is not limited to the use of liquids or gases. In some embodiments, the material is a slurry, a gel, or the like. In some embodiments, a cooling fluid is used. Any coolant fluid now known or later developed can be used. Exemplary coolant fluids include, but are not limited to, one or more of the following or a combination thereof: water, ethylene glycol, air, an inert gas, carbon dioxide, nitrogen, helium, sulfur hexafluoride, ionic solutions (e.g., sodium chloride with or without potassium and other ions), dextrose in water, lactated Ringer's solution, organic chemical solutions (e.g., ethylene glycol, diethylene glycol, or propylene glycol), oils (e.g., mineral oil, silicone oil, fluoroalkane oil), liquid metals, Freons, halogenated methanes, liquefied propane, other halogenated alkanes, anhydrous ammonia, sulfur dioxide. In some embodiments, the coolant fluid is pre-cooled before delivery to the energy delivery device. In some embodiments, the coolant fluid enters the energy delivery device after being cooled by a cooling unit. In some embodiments, the material passing through the dielectric material is designed to undergo an endothermic reaction upon contact with the additional material.

Energy delivery devices with coolant delivery channels are configured to allow for control of parameters of fluid infusion through the device. In some embodiments, the device is manually adjusted as needed by a user (e.g., a physician or technician). In some embodiments, the adjustment is automated. In some embodiments, the device is configured to include or be used with a sensor that provides information to a user or an automated system (e.g., including a processor and/or software configured to receive this information and adjust fluid infusion or other device parameters accordingly). Parameters that can be adjusted include, but are not limited to, fluid infusion rate, concentration of ions or components that affect fluid properties (e.g., dielectric properties, heat transfer properties, flow rate, etc.), fluid temperature, fluid type, and mixing ratio (e.g., gas/fluid mixtures for precise tuning or cooling). Thus, energy delivery devices with coolant delivery channels are configured to utilize a feedback loop that can alter one or more desired parameters to more accurately tune the device (e.g., antenna) or accelerate fluid infusion if the device, portions of the device, or tissue of a subject reaches an undesirable temperature (or a temperature persists for an undesirable period of time).

Energy delivery devices having coolant delivery channels offer numerous advantages over currently available systems and devices. For example, by providing a coaxial transmission line with a channel carved out and substantially removing the bulk of solid dielectric material, the coaxial transmission line can be designed so that it can fit within a very small needle (e.g., an 18-20 gauge needle or smaller). Typically, medical devices configured to deliver microwave energy are designed to fit within large needles due to the bulk of the dielectric material. Other devices use a cooled external water jacket, which also increases the size of the probe and can increase tissue damage. These large probe sizes increase the risk of complications when used in the chest and abdomen. In some embodiments of the present invention, the maximum outer diameter of the portion of the device that enters the subject is 16-18 gauge or smaller (20 gauge or smaller).

Figure 6 shows a schematic cross-sectional view of one or more standard coaxial cable embodiments of the present invention with coolant channels. As shown in Figure 6, a conventional coaxial cable 600 and two exemplary coaxial cables 610 and 620 according to the present invention are provided. A coaxial cable generally consists of three separate compartments: a metallic inner conductor 630, a metallic outer conductor 650, and the space between them. The space between these compartments is typically filled with a low-loss dielectric material 640 (e.g., polytetrafluoroethylene or PTFE) to mechanically support the inner conductor and retain it in place via the outer conductor. The characteristic impedance of a coaxial cable is determined by the ratio of the inner conductor diameter to the dielectric material diameter (i.e., the inner diameter of the outer conductor) and the dielectric constant of the space between them. Typically, the dielectric constant is fixed because it is formed from a solid polymer. However, in embodiments of the present invention, a fluid with a variable dielectric constant (or conductivity) at least partially occupies this space, allowing the cable's characteristic impedance to be adjusted.

Still referring to FIG6 , in one embodiment of the present invention, a coaxial cable 610 has an outer layer of dielectric material partially removed to create a channel between the dielectric material 640 and the outer conductor 650. In the illustrated embodiment, the created space is divided into four distinct channels 670 by adding support wires 660, which are configured to maintain the space between the outer conductor 650 and the solid dielectric material 640. The support wires 660 can be made of any desired material and can be the same or different from the solid dielectric material 640. In some embodiments, to prevent undesirable heating of the device (e.g., of the outer conductor), the support wires 660 are made of a biocompatible and meltable material (e.g., wax). The presence of multiple channels allows one or more channels to allow flow in one direction (toward the proximal end of the cable) while one or more other channels allow flow in the opposite direction (toward the distal end of the cable).

Still referring to FIG6 , in another embodiment, the coaxial cable 620 has a significant portion of the solid dielectric material 640 removed. This embodiment can be created, for example, by stripping the solid dielectric material 640 down to the surface of the inner conductor 630 on each of four sides. In another embodiment, multiple strips of dielectric material 640 are applied to the inner conductor 630 to create this structure. In this embodiment, four channels 670 are created. By removing a significant amount of dielectric material 640, the diameter of the outer conductor 650 is significantly reduced. The corners provided by the remaining dielectric material 640 provide support to maintain the position of the outer conductor 650 relative to the inner conductor 630. In this embodiment, the overall diameter of the coaxial cable 620 and the device is significantly reduced.

In some embodiments, the device has a coolant channel formed by inserting a tubing configured to circulate coolant through the dielectric portion or the inner or outer conductor of any energy-emitting device of the present invention. FIG7 shows a coolant-circulating tube 700 (e.g., a coolant needle, catheter) positioned within an energy-emitting device 710 having an outer conductor 720, a dielectric material 730, and an inner conductor 740. As shown in FIG7 , the tubing 700 is positioned along the outer edge of the dielectric material 730 and the inner edge of the outer conductor 720, while the inner conductor 740 is positioned approximately in the center of the dielectric material 730. In some embodiments, the tubing 700 is positioned within the dielectric material 730 so that it does not contact the outer conductor 720. In some embodiments, the tubing 700 has multiple channels (not shown) for the purpose of recirculating cooling water within the tubing 700 without transferring coolant into the dielectric material 730 and/or outer conductor 720, thereby cooling the dielectric material 730 and/or outer conductor 720 using the exterior of the tubing 700.

Energy delivery device with center-fed dipole

In some embodiments, the energy delivery systems of the present invention utilize an energy delivery device that utilizes a center-fed dipole assembly (see, e.g., U.S. patent application Ser. No. 11/728,457; incorporated herein by reference in its entirety). This device is not limited to a particular configuration. In some embodiments, the device comprises a center-fed dipole that heats a tissue region by applying energy (e.g., microwave energy). In some embodiments, the device comprises a coaxial cable connected to a hollow tube (e.g., wherein the inner diameter is at least 50% of the outer diameter; e.g., wherein the inner diameter is substantially similar to the outer diameter). The coaxial cable can be a standard coaxial cable, or it can be a coaxial cable having a dielectric component with near-zero conductivity (e.g., air). The hollow tube is not limited to a particular design configuration. In some embodiments, the hollow tube has the shape (e.g., the diameter) of, for example, a 20-gauge needle. Preferably, the hollow tube is made of a solid, rigid conductive material (e.g., any number of metals, conductor-coated ceramics, polymers, etc.). In some embodiments, the hollow tube is configured with a sharp point or with a stylet at its distal end to allow for direct insertion of the device into a tissue region without the use of, for example, a cannula. The hollow tube is not limited to a particular composition (e.g., metal, plastic, ceramic). In some embodiments, the hollow tube comprises, for example, copper or copper alloys with other strengthening metals, silver or silver alloys with other strengthening metals, gold-plated copper, metal-plated glass ceramics (machinable ceramics), metal-plated hardened polymers, and/or combinations thereof. The stylet tip can be made of any material. In some embodiments, the tip is made of a hardened resin. In some embodiments, the tip is metal. In some embodiments, the stylet tip is made of titanium or a titanium equivalent. In some embodiments, the stylet tip is red-hot zirconium oxide or a zirconium equivalent. In some such embodiments, the metal tip is an extension of the metal portion of the antenna and is electrically active.

In some embodiments, the center-fed dipole is configured to adjust its energy delivery characteristics in response to heating, thereby providing more optimized energy delivery over the entire duration of the process. In some embodiments, this is achieved by using a material that changes volume in response to temperature changes, such that the volume change alters the device's energy delivery characteristics. For example, in some embodiments, an expandable material is placed within the device, thereby pushing the resonant portion of the center-fed dipole assembly or stylet toward the distal end of the device in response to heating. This changes the device's tuning to maintain more optimized energy delivery. The maximum amount of movement can be constrained, for example by providing a locking mechanism that prevents extension beyond a specific point. Energy delivery devices employing center-fed dipole assemblies are not limited to the method of connecting the hollow tube to the coaxial cable. In some embodiments, a portion of the outer conductor at the distal end of the coaxial cable feedline is removed, exposing an area of solid dielectric material. The hollow tube can be positioned over the exposed dielectric material and attached by any means. In some embodiments, a physical gap is provided between the outer conductor and the hollow tube. In some embodiments, the hollow tube is capacitively or conductively attached to a center point of the feed line such that the electrical length of the hollow tube comprises a frequency resonant structure when inserted into tissue.

In use, an energy delivery device employing a center-fed dipole assembly is configured such that an electric field maximum is generated at the open distal end of the hollow tube. In some embodiments, the distal end of the hollow tube has a pointed shape to assist in inserting the device through a subject and into a tissue region. In some embodiments, the entire device is hard and rigid to facilitate direct linear guidance of insertion into the target site. In some embodiments, the structure resonates at a frequency, for example, of approximately 2.45 GHz, characterized by a minimum reflection coefficient at this frequency (measured at the proximal end of the feedline). The resonant frequency can be altered by varying the dimensions of the device (e.g., length, feed point, diameter, gap, etc.) and the materials of the antenna (dielectric material, conductor, etc.). A low reflection coefficient at the desired frequency ensures efficient energy transfer from the antenna to the surrounding medium.

Preferably, the length of the hollow tube is λ/2, where λ is the wavelength of the electromagnetic field in the medium of interest that resonates within the medium (e.g., approximately 18 cm for 2.45 GHz in the liver). In some embodiments, the length of the hollow tube is approximately λ/2, where λ is the wavelength of the electromagnetic field in the medium of interest that resonates within the medium, such that minimum power reflection is measured at the proximal end. However, deviations from this length can be used to produce a resonant wavelength (e.g., when the surrounding material changes). Preferably, the inner conductor of the coaxial cable extends with its distal end at the center of the tube (e.g., at a distance of λ/4 from the end of the tube) and is configured so that the inner conductor maintains electrical contact at the center of the tube, although deviations from this position are permitted (e.g., to produce a resonant wavelength).

The hollow tube portion of the present invention can have a variety of shapes. In some embodiments, the tube is cylindrical throughout its entire length. In some embodiments, the tube tapers from a central position, resulting in a smaller diameter at its distal end than at its center. A smaller point at the distal end can assist in penetrating the body to reach the target area. In some embodiments where the shape of the hollow tube deviates from a cylindrical shape, the tube maintains a symmetrical structure around its longitudinal center. However, the device is not limited to the shape of the hollow tube, as long as the functional properties (i.e., the ability to deliver the desired energy to the target area) are achieved.

In some embodiments, the center-fed dipole assembly can be added to the distal end of various ablation devices to provide the benefits described herein. Likewise, various devices can be modified to accept the center-fed dipole assembly of the present invention.

In some embodiments, the device has a small outer diameter. In some embodiments, the center-fed dipole assembly of the present invention is used to directly insert the invasive component of the device into the subject. In some such embodiments, the device does not include a cannula, allowing the invasive component to have a smaller outer diameter. For example, the invasive component can be designed so that it fits within or is the size of a very small needle (e.g., an 18-20 gauge needle or smaller).

FIG8 schematically illustrates the distal end of a device 800 of the present invention (e.g., an antenna for an ablation device) comprising a center-fed dipole assembly 810 of the present invention. Those skilled in the art will recognize any number of alternative configurations for implementing the physical and/or functional aspects of the present invention. As shown, the center-fed dipole device 800 comprises a hollow tube 815, a coaxial transmission line 820 (e.g., a coaxial cable), and a stylet 890. The center-fed dipole device 800 is not limited to a particular size. In some embodiments, the center-fed dipole device 800 is small enough to be positioned at a tissue region (e.g., the liver) for the purpose of delivering energy (e.g., microwave energy) to the tissue region.

Still referring to FIG8 , hollow tube 815 is not limited to a particular material (e.g., plastic, ceramic, metal, etc.). Hollow tube 815 is not limited to a particular length. In some embodiments, the length of the hollow tube is λ/2, where λ is the wavelength of the electromagnetic field in the medium of interest (e.g., approximately 18 cm for 2.45 GHz in the liver). Hollow tube 815 is coupled to coaxial transmission line 820 so that hollow tube 815 is attached to coaxial transmission line 820 (see below for details). Hollow tube 815 contains hollow tube substance 860. Hollow tube 815 is not limited to a particular type of hollow tube substance. In some embodiments, hollow tube substance 860 is air, a fluid, or a gas.

Still referring to FIG. 8 , hollow tube 815 is not limited to a particular shape (e.g., cylindrical, triangular, square, rectangular, etc.). In some embodiments, hollow tube 815 is needle-shaped (e.g., a 20-gauge needle, an 18-gauge needle). In some embodiments, hollow tube 815 is divided into two sections, each having a variable length. As shown, hollow tube 815 is divided into two sections, each having an equal length (e.g., each section having a length of λ/4). In such embodiments, the shapes of each section are symmetrical. In some embodiments, the hollow tube has a diameter equal to or smaller than that of a 20-gauge needle, a 17-gauge needle, a 12-gauge needle, etc.

Still referring to Figure 8, the distal end of the hollow tube 815 is engaged with the stylet 890. The device 800 is not limited to a particular stylet 890. In some embodiments, the stylet 890 is designed to facilitate percutaneous insertion of the device 800. In some embodiments, the stylet 890 engages the hollow tube 815 by sliding within the hollow tube 815, thereby securing the stylet 890. In some embodiments, the stylet 890 can be made of any material. In some embodiments, the stylet 890 is made of a hardened resin. In some embodiments, the stylet 890 is metal. In some embodiments, the stylet 890 is made of titanium or an equivalent of titanium. In some embodiments, the stylet 890 is red-hot to generate zirconium oxide and an equivalent of zirconium oxide. In some such embodiments, the stylet 890 is an extension of the metal portion of the antenna and is electrically active.

Still referring to FIG8 , the coaxial transmission line 820 is not limited to a particular type of material. In some embodiments, the proximal coaxial transmission line 820 is constructed from commercial standard 0.047-inch semi-rigid coaxial cable. In some embodiments, the coaxial transmission line 820 is metal-plated (e.g., silver-plated, copper-plated), although the present invention is not limited in this regard. The proximal coaxial transmission line 820 is not limited to a particular length.

Still referring to FIG. 8 , in some embodiments, a coaxial transmission line 820 includes a coaxial center conductor 830, a coaxial dielectric material 840, and a coaxial outer conductor 850. In some embodiments, the coaxial center conductor 830 is configured to conduct a cooling fluid along its length. In some embodiments, the coaxial center conductor 830 is hollow. In some embodiments, the coaxial center conductor 830 has a diameter of, for example, 0.012 inches. In some embodiments, the coaxial dielectric material 840 is polytetrafluoroethylene (PTFE). In some embodiments, the coaxial dielectric material 840 has near-zero conductivity (e.g., air, fluid, gas).

Still referring to FIG8 , the distal end of the coaxial transmission line 820 is configured to engage the proximal end of the hollow tube 815. In some embodiments, the coaxial center conductor 830 and the coaxial dielectric material 840 extend to the center of the hollow tube 815. In some embodiments, the coaxial center conductor 820 extends further into the hollow tube 815 than the coaxial dielectric material 840. The coaxial center conductor 820 is not limited to a specific extension into the hollow tube 815. In some embodiments, the coaxial center conductor 820 extends a length λ/4 into the hollow tube 815. The distal end of the coaxial transmission line 820 is not limited to a specific manner of engaging the proximal end of the hollow tube 815. In some embodiments, the proximal end of the hollow tube engages the coaxial dielectric material 840, thereby securing the hollow tube 815 to the coaxial transmission line 820. In some embodiments where the coaxial dielectric material 840 has a near-zero conductivity, the hollow tube 815 is not secured to the coaxial transmission line 820. In some embodiments, the distal end of the coaxial center conductor 830 engages the wall of the hollow tube 815 directly or through contact with a conductive material 870, which may be made of the same material as the coaxial center conductor or may be a different material (e.g., a different conductive material).

Still referring to FIG. 8 , in some embodiments, a gap 880 is present between the distal end of the coaxial transmission line outer conductor 850 and the hollow tube 815, thereby exposing the coaxial dielectric material 840. Gap 880 is not limited to a particular size or length. In some embodiments, gap 880 ensures that the electric field is maximized at the proximal end of the coaxial transmission line 880 and the distal opening of the hollow tube 815. In some embodiments, the center-fed dipole device 810 resonates at a frequency of approximately 2.45 GHz, characterized by a minimum reflection coefficient at this frequency. By varying the dimensions (e.g., length, feed point, diameter, gap, etc.) and materials (dielectric material, conductor, etc.) of the device, the resonant frequency can be altered. The low reflection coefficient at this frequency ensures efficient energy transfer from the antenna to the surrounding medium.

Still referring to FIG. 8 , in some embodiments, gap 880 is filled with a material (e.g., epoxy) to bridge the coaxial transmission line 820 and hollow tube 815. The device is not limited to a particular type or kind of substantive material. In some embodiments, the substantive material does not interfere with the generation or emission of the energy field by the device. In some embodiments, the material is biocompatible and heat-resistant. In some embodiments, the material lacks or substantially lacks electrical conductivity. In some embodiments, the material further bridges the coaxial transmission line 820 and hollow tube 815 with the coaxial center conductor 830. In some embodiments, the substantive material is a curable resin. In some embodiments, the material is a dental enamel (e.g., XRV tempered glass enamel; see also U.S. Patent Nos. 6,924,325, 6,890,968, 6,837,712, 6,709,271, 6,593,395, and 6,395,803, each of which is incorporated herein by reference in its entirety). In some embodiments, the solid material is cured (e.g., using a curing light such as an L.E. Demetron II light) (see, e.g., U.S. Patent Nos. 6,994,546, 6,702,576, 6,602,074, and 6,435,872). Thus, the present invention provides ablation devices comprising a cured enamel resin. Such a resin is biocompatible and rigid and strong.

Energy delivery device having a linear array of antenna assemblies

In some embodiments, the energy delivery system of the present invention utilizes an energy delivery device having a linear array of antenna assemblies (see, for example, U.S. Provisional Patent Application No. 60/831,055; incorporated herein by reference in its entirety). This device is not limited to a particular configuration. In some embodiments, the energy delivery device having a linear array of antenna assemblies includes an antenna comprising an inner conductor and an outer conductor, wherein the outer conductor is provided in two or more linear segments separated by a gap, such that the lengths and positions of the segments are configured to optimize energy delivery at the distal end of the antenna. For example, in some embodiments, the antenna includes a first segment of the outer conductor spanning from the proximal end to a region near the distal end of the antenna and a second segment of the outer conductor distal to the first segment, wherein the gap separates or partially separates the first and second segments. The gap may fully define the outer conductor or may only partially define the outer conductor. In some embodiments, the length of the second segment is λ/2, λ/4, etc., although the present invention is not limited thereto. In some embodiments, one or more additional segments (e.g., a third, fourth, or fifth) are provided distal to the second segment, each segment separated from the other segments by a gap. In some embodiments, the antenna terminates at a conductive terminal in electronic communication with the inner conductor. In some embodiments, the conductive terminal comprises a circular disk having a diameter substantially the same as that of the outer conductor. Such an antenna provides multiple energy delivery peaks along the length of the distal end of the antenna, providing a wider energy delivery zone to a larger target area of tissue. The orientation and location of the peaks are controlled by selecting the length of the outer conductor segment and the amount of energy delivered.

Energy delivery devices having linear arrays of antenna components are not limited by the properties of the various components of the antenna. A variety of components can be used to provide optimal performance, including, but not limited to, using various materials for the inner and outer conductors, using various materials and configurations for the dielectric material between the inner and outer conductors, and using a coolant provided by various methods.

In certain embodiments, the device includes a linear antenna comprising an outer conductor encapsulated around an inner conductor, wherein the inner conductor is configured to receive and transmit energy (e.g., microwave energy), wherein the outer conductor has a series of gap regions (e.g., at least two) positioned along the outer conductor, wherein the inner conductor is exposed at the gap regions, and wherein energy transmitted along the inner conductor is emitted through the gap regions. The device is not limited to a particular number of gap regions (e.g., 2, 3, 4, 5, 6, 10, 20, 50). In some embodiments, the gaps are positioned to facilitate, for example, linear ablation. In some embodiments, the inner conductor comprises a dielectric layer encapsulating a central transmission line. In some embodiments, the dielectric layer has near-zero conductivity. In some embodiments, the device further comprises a stylet. In some embodiments, the device further comprises a tuning element for adjusting the amount of energy delivered through the gap regions. In certain embodiments, when used in a tissue ablation setting, the device is configured to deliver a sufficient amount of energy to ablate a tissue region or induce thrombosis.

Energy delivery devices having linear arrays of antenna assemblies offer numerous advantages over currently available systems and devices. For example, a major drawback of currently available medical devices utilizing microwave energy is that the released energy is delivered locally, thereby preventing energy delivery at deeper and more intensive scales. The present device overcomes this limitation by providing an applicator device having a linear array of antenna assemblies that is configured to deliver energy (e.g., microwave energy) at deeper and more extensive scales (e.g., as opposed to local delivery). Such a device is particularly useful for tissue ablation of dense and/or thick tissue regions (e.g., tumors, organ lumens) and particularly deep tissue regions (e.g., large cardiac regions, brain, bone).

Capacitively coupled antenna/precision probe

Experiments conducted during the development of embodiments of the present invention determined that coupling a "precision antenna" with an existing antenna (e.g., providing a trocar at the distal end of a triaxial antenna that is capacitively coupled to the antenna's inner conductor) resulted in improved ablation. For example, coupling a "precision antenna" with an existing antenna resulted in a larger ablation zone compared to an antenna without such coupling. For example, coupling a "precision antenna" or "precision probe" with an existing antenna resulted in a larger spherical ablation zone compared to an antenna without such coupling. Furthermore, coupling a "precision antenna" or "precision probe" with an existing antenna resulted in a superior field pattern and reduced reflected power compared to an antenna without such coupling.

For example, Figure 34 shows ablated tissue created in ex vivo bovine tissue using A) a capacitively coupled antenna (e.g., including a precision probe) and B) an antenna without such coupling. As can be seen in Figure 34, the ablation from the precision probe exhibits less tissue charring and cavitation. In fact, as shown in Figure 34B, the antenna exhibits extensive tissue charring and cavitation around the trocar region of the antenna. The trocar region, adhered to the desiccated tissue, makes removal difficult. The temperature in the trocar region exceeds the limits of low-friction thermoplastic materials (e.g., PTFE, FEP, PET) that can be used to cover the trocar. However, as shown in Figure 34A, the amount of energy that the precision probe allows to couple to the trocar is controlled by the ratio of the antenna tube to the trocar diameter and the amount of overlap with the trocar. Indeed, by selecting the correct dimensions, the energy coupling to the trocar can be optimized to maintain the maximum trocar temperature at a desired (e.g., safe) level.

Figure 35 graphically summarizes the average transverse ablation diameters for capacitively coupled antennas (e.g., precision probes) and antennas without such coupling (for 30 watts of input power at various durations). In fact, as shown in Figure 35, the precision probes create larger ablations at equivalent incident power due to, for example, superior field patterns and higher reflected power efficiency (less than 1% for the precision probes and less than 10% for the uncoupled antennas).

Thus, in certain embodiments, the present invention provides a precision antenna or precision probe that couples with an existing antenna.

The precision probe is not limited to coupling with a particular type of antenna. In some embodiments, the antenna has an inner conductor. In some embodiments, the antenna is a triaxial antenna (see, e.g., U.S. Patent No. 7,101,369; see also U.S. Patent Application Nos. 10/834,802, 11/236,985, 11/237,136, 11,237,430, 11/440,331, 11/452,637, 11/502,783, 11/514,628; International Patent Application No. PCT/US05/14534; incorporated herein by reference in its entirety). In some embodiments, the antenna is a coaxial antenna. In some embodiments, the antenna is any type of device (e.g., an ablation device, a surgical device, etc.) configured to deliver (e.g., transmit) energy (see, e.g., U.S. Patent Nos. 7,101,369, 7,033,352, 6,893,436, 6,878,147, 6,823,218, 6,817,999, 6,635,055, 6,471,696, 6,383,182, 6,312,427, 6,287,302, 6,277,113, 6,251,128, 6,245,062, 6,026,331, 6,016,811, etc.). ,803, 5,800,494, 5,788,692, 5,405,346, 4,494,539; U.S. Patent Application Serial Nos. 11/728,460, 11/728,457, 11/728,428, 11/237,136, 11/236,985, 10/980,699, 10/961,994, 10/961,761, 10/834,802, 10/370,179, 09/847,181; UK Patent Application Nos. 2,406,521, 2,388,039; European Patent No. 1395190; International Patent Application No. WO 06/008481, WO 06/002943, WO 05/034783, WO 04/112628, WO 04/033039, WO 04/026122, WO 03/088858, WO 03/039385 WO 95/04385; each of which is incorporated herein by reference in its entirety).

The precision probe is not limited to a particular configuration. FIG36 illustrates an exemplary configuration and method for assembling a precision probe with an ablation antenna. This figure illustrates capacitive coupling between a metal trocar and the inner conductor of a coaxial antenna. The distal end of the coaxial antenna's inner conductor is fitted with a conductive (e.g., metal; for example, copper, silver, gold, etc.) fitting. This metal fitting abuts the antenna's dielectric material (e.g., the dielectric material of a coaxial cable or the dielectric material of a cannula inserted over the inner conductor) at its proximal end. In some embodiments, the fitting is positioned so that the inner conductor in the fitting does not reach the distal end of the fitting. The distal end of the fitting contacts an insulator (e.g., a ceramic insulator) that separates the fitting from the trocar and attaches it to the trocar. These components are sized and positioned to provide a desired energy distribution to the sample being treated (e.g., a tissue sample). In some embodiments, the device is configured to allow the antenna to have a larger spherical ablation zone, a more spherical ablation zone, and/or reduced reflected power compared to an antenna without such capacitive coupling (e.g., compared to an antenna with a physical coupling of the inner conductor to the trocar).

The precision probe is not limited to a particular shape and/or design. In some embodiments, the shape of the precision probe enables it to be mounted on the inner conductor of the antenna. In some embodiments, the shape and/or design of the precision probe is cylindrical. In some embodiments, the shape and/or design of the precision probe is tubular.

The precision probe is not limited to a specific location within the antenna. In some embodiments, to accommodate the precision probe, the outer conductor and dielectric of the antenna are removed to create a portion of the conductor along the inner conductor in which the precision probe is to be positioned (e.g., thereby creating an exposed inner conductor area). In some such embodiments, the precision probe is positioned along the entire exposed inner conductor area. In some such embodiments, an antenna cover (e.g., a polytetrafluoroethylene or PTFE antenna cover) is positioned along a portion of the exposed inner conductor, while the precision probe is positioned along the remainder of the exposed inner conductor. For example, FIG36 depicts the steps for coupling a precision probe to an existing antenna having an inner conductor, a dielectric, an outer conductor, and a trocar.

The conductive assembly of the precision probe is not limited to a particular method of coupling to the inner conductor of the antenna. In some embodiments, the assembly is soldered to the inner conductor. In some embodiments, the assembly is brazed to the inner conductor. In some embodiments, the assembly is crimped to the inner conductor. In some embodiments, the assembly is spot welded to the inner conductor. In some embodiments, the connection between the precision probe and the inner conductor is electrically conductive.

The precision probe is not limited to a particular size. In some embodiments, the precision probe is sized to accommodate any type or size of antenna (e.g., inner conductor or antenna). In some embodiments, the diameter of the precision probe is as large as possible to minimize the impedance formed in the outer needle cap.

The present invention is not limited to the specific use of an antenna coupled to a precision probe. In fact, it is contemplated that an antenna coupled to a precision probe may be used in any of the applications described herein (see, eg, Section X).

processor

In some embodiments, the energy delivery systems of the present invention utilize processors that monitor and/or control one or more components of the system and/or provide feedback regarding one or more components of the system. In some embodiments, the processor is provided within a computer module. The computer module may also include software used by the processor to implement one or more of its functions. For example, in some embodiments, the systems of the present invention provide software for adjusting the amount of microwave energy delivered to a tissue region by monitoring one or more characteristics of the tissue region, including, but not limited to, the size and shape of the target tissue, the temperature of the tissue region, and the like (e.g., via a feedback system) (see, e.g., U.S. patent application serial numbers 11/728,460, 11/728,457, and 11/728,428; each of which is incorporated herein by reference in its entirety). In some embodiments, the software is configured to provide real-time information (e.g., monitoring information). In some embodiments, the software is configured to interact with the energy delivery systems of the present invention, enabling it to increase or decrease (e.g., adjust) the amount of energy delivered to the tissue region. In some embodiments, the software is designed to direct coolant for distribution, for example, to an energy delivery device, such that the coolant is at a desired temperature prior to use of the energy delivery device. In some embodiments, the type of tissue being treated (e.g., liver) is entered into the software to allow the processor to adjust (e.g., tune) the microwave energy delivered to the tissue region based on precalibrated methods for that specific type of tissue region. In other embodiments, the processor generates a table or graph based on the specific type of tissue region to display characteristics useful to the system user. In some embodiments, the processor provides an energy delivery algorithm that, for example, slowly ramps down power to avoid tissue lysis due to rapid outgassing caused by high temperatures. In some embodiments, the processor allows the user to select power, treatment duration, different treatment methods for different tissue types, simultaneous power application to antennas in multiple antenna patterns, switching power delivery between antennas, coherent and incoherent phasing, and the like. In some embodiments, the processor is configured to create a database of information (e.g., required energy levels, treatment durations for tissue regions based on specific patient characteristics) related to ablation treatments for specific tissue regions based on previous treatments with similar or dissimilar patient characteristics. In some embodiments, the processor is operated by a remote controller.

In some embodiments, the processor is used to generate, for example, an ablation map based on inputs of tissue characteristics (e.g., tumor type, tumor size, tumor location, surrounding vascular information, blood flow information, etc.). In such embodiments, the processor can guide the placement of an energy delivery device to achieve the desired ablation according to the ablation map.

In some embodiments, a software package that interacts with a processor is provided that allows the user to input parameters of the tissue to be treated (e.g., the type, size, and location of the tumor or tissue portion to be ablated, the location of blood vessels or fragile structures, and blood flow information), and then draws the desired ablation zone on a CT or other image to provide the desired results. The probe can be placed into the tissue, and the computer generates the desired ablation zone based on the provided information. This application can include feedback. For example, CT, MRI, ultrasound imaging, and temperature measurement can be used during ablation. This data is fed back to the computer, and the parameters are readjusted to produce the desired results.

In some embodiments, user interface software is provided to facilitate monitoring and/or operation of the components of the energy delivery system. In some embodiments, the user interface software is operated by a touch screen interface. In some embodiments, the user interface software can be implemented and operated in a sterile setting (e.g., an operating room) or in a non-sterile setting. In some embodiments, the user interface software is implemented and operated in a procedure device hub (e.g., via a processor). In some embodiments, the user interface software is implemented and operated in a procedure cart (e.g., via a processor). The user interface software is not limited to a specific functionality. Examples of functionality associated with the user interface software include, but are not limited to, tracking the number of uses of each component within the energy delivery system (e.g., tracking the number of times the energy delivery device has been used), providing and tracking the real-time temperature of each component or portion of each component (e.g., providing real-time temperatures at various locations along the energy delivery device (e.g., at the handle, at the bonding area, at the tip)) (e.g., providing real-time temperatures of cables associated with the energy delivery system), providing and tracking the real-time temperature of tissue being treated, providing automatic shutdown of part or all of the energy delivery system (e.g., emergency shutdown), generating reports based on accumulated data, such as before, during, and after a procedure, providing audible and/or visual alerts to the user (e.g., alerts indicating that a procedure has begun and/or ended, alerts indicating that a temperature has reached an abnormal level, alerts indicating that the length of a procedure has exceeded a default value, etc.). Figures 32A, 32B, and 32C illustrate examples of user interface software for the energy delivery system of the present invention. As shown in Figure 32A, the user interface software is designed to display and allow adjustment of the time, temperature, type of operation (e.g., test, bonding, stop ablation, and cauterize), and power of each probe (e.g., energy delivery device). FIG32B shows a report generated by the user interface software showing power, elapsed time, target time, and related messages. FIG32C shows user interface tools associated with the user interface software, including annotated system log, system diagnostic log, procedure history, default time, default power, display brightness, time settings, and additional features (e.g., time display options, time zone options, call home options, time settings options, and audio volume options).

As used herein, the terms "computer memory" and "computer storage" refer to any storage medium that is readable by a computer processor. Examples of computer memory include, but are not limited to, random access memory (RAM), read-only memory (ROM), computer chips, optical disks (e.g., compact discs (CDs), digital video discs (DVDs), etc.), magnetic disks (e.g., hard disk drives (HDDs), floppy disks, ZIP and RTM disks), magnetic tape, and solid-state storage devices (e.g., memory cards, "flash" media, etc.).

As used herein, the term "computer-readable medium" refers to any device or system for storing and providing information (e.g., data and instructions) to a computer processor. Examples of computer-readable media include, but are not limited to, optical discs, magnetic disks, magnetic tapes, solid-state media, and servers over a network for streaming media.

As used herein, the terms "processor" and "central processing unit" or "CPU" are used interchangeably and refer to a device that can read a program from computer storage (e.g., ROM or other computer memory) and execute a set of steps in accordance with the program.

Imaging system

In some embodiments, the energy delivery system of the present invention utilizes an imaging system including an imaging device. The energy delivery system is not limited to a particular type of imaging device (e.g., an endoscopic device, a computer-assisted neurosurgery stereotactic navigation device, a thermal sensor positioning system, a motion velocity sensor, a steering line system, intraoperative ultrasound, interstitial ultrasound, microwave imaging, ultrasound tomography, dual energy imaging, fluoroscopy, computed tomography magnetic resonance imaging, nuclear medicine imaging equipment triangulation imaging, thermoacoustic imaging, infrared and/or laser imaging, electromagnetic imaging) (see, e.g., U.S. Patent Nos. 6,817,976, 6,577,903, 5,697,949, 5,603,697 and International Patent Application No. WO 06/005,579; each of which is incorporated herein by reference in its entirety). In some embodiments, the system utilizes an endoscopic camera, imaging assembly, and/or navigation system to allow or assist in the placement, positioning, and/or monitoring of any object used with the energy system of the present invention.

In some embodiments, the energy delivery system provides software configured for use with an imaging device (e.g., CT, MRI, ultrasound). In some embodiments, the imaging device software allows a user to make predictions based on known thermodynamic and electrical properties of tissue and vasculature, as well as the location of the antenna. In some embodiments, the imaging software allows for the generation of a three-dimensional map of the location of the tissue region (e.g., tumor, arrhythmia) and the location of the antenna, thereby generating a predicted map of the ablation zone.

In some embodiments, the imaging systems of the present invention are used to monitor ablation procedures (e.g., microwave thermal ablation procedures, radiofrequency thermal ablation procedures). The present invention is not limited to a particular type of monitoring. In some embodiments, the imaging system is used to monitor the amount of ablation occurring in a specific tissue region undergoing a thermal ablation procedure. In some embodiments, monitoring is performed in conjunction with an ablation device (e.g., an energy delivery device) such that the amount of energy delivered to a specific tissue region is dependent upon the imaging of that tissue region. The imaging system is not limited to a particular type of monitoring. The present invention is not limited to the subject monitored by the imaging device. In some embodiments, the monitoring involves imaging blood perfusion in a specific region to detect changes in that region, for example, before, during, and after a thermal ablation procedure. In some embodiments, the monitoring includes, but is not limited to, MRI imaging, CT imaging, ultrasound imaging, nuclear medicine imaging, and fluoroscopic imaging. For example, in some embodiments, a contrast agent (e.g., iodine or other suitable CT contrast agent; gadolinium chelate or other suitable MRI contrast agent; microbubbles or other suitable ultrasound contrast agent; etc.) is administered to a subject (e.g., a patient) prior to a thermal ablation procedure, and changes in blood perfusion are monitored based on the contrast agent perfused through the specific tissue region undergoing the ablation procedure. In some embodiments, the monitoring is qualitative information regarding the properties of the ablation zone (e.g., diameter, length, cross-sectional area, volume). The imaging system is not limited to a particular technique for monitoring qualitative information. In some embodiments, techniques for monitoring qualitative information include, but are not limited to, non-imaging techniques (e.g., time-domain reflectometry, time-of-flight pulse detection, frequency-modulated distance detection, eigenmode or resonant frequency detection, or reflection and transmission at any frequency, based solely on an interstitial device or in conjunction with other interstitial devices or external equipment). In some embodiments, the interstitial device provides imaging signals and/or imaging detection (e.g., electroacoustic imaging, electromagnetic imaging, electrical impedance tomography). In some embodiments, non-imaging techniques are used to monitor the dielectric properties of the medium surrounding the antenna and detect the interface between the ablation zone and normal tissue through various means, including resonant frequency detection, reflectometry or ranging techniques, power reflection/transmission from the interstitial antenna or an external antenna, etc. In some embodiments, the qualitative information is an estimate of the ablation status, power delivery status, and/or a simple go/no-go check to ensure that power is being applied. In some embodiments, the imaging system is designed to automatically monitor a specific tissue region at any frequency (e.g., every second, every minute, every ten minutes, every hour, etc.). In some embodiments, the present invention provides software designed to automatically acquire images of a tissue region (e.g., MRI, CT, ultrasound, nuclear medicine, fluoroscopy), automatically detect any changes in the tissue region (e.g., blood perfusion, temperature, amount of necrotic tissue, etc.), and automatically adjust the amount of energy delivered to the tissue region via an energy delivery device based on these changes. Similarly, algorithms can be applied to predict the shape and size of the tissue region to be ablated (e.g., tumor shape), so that the system can recommend the type, number, and location of ablation probes that will effectively treat the region. In some embodiments, the system is configured with a navigation or guidance system (e.g., using triangulation or other localization procedures) to assist or guide the placement and use of the probes.

For example, such procedures can be used to track the progress of an ablation or other therapeutic procedure using or without the enhancement of a contrast material. Subtraction methods (e.g., similar to those used for digital subtraction angiography) can be used. For example, a first image can be taken at a first time point. Subsequent images subtract some or all of the information from the first image to make it easier to observe changes in the tissue. Similarly, accelerated imaging techniques can be used that apply "undersampling" techniques (as opposed to Nyquist sampling). It is anticipated that these techniques provide a good signal-to-noise ratio using multiple low-resolution images taken over time. For example, a technique called HYPER (Highly Constrained Projection Reconstruction) can be used for MRI, which can be applied to system embodiments of the present invention.

Because thermal treatment causes blood vessels to coagulate at temperatures exceeding, for example, 50°C, this coagulation reduces blood supply to areas that have already completely coagulated. Coagulated tissue regions do not enhance after contrast agent administration. In some embodiments, the present invention utilizes an imaging system to automatically track the progress of an ablation procedure, for example by administering a small test injection of contrast agent to determine the arrival time of the contrast agent at the tissue region in question and establish baseline enhancement. Following the initiation of the ablation procedure, a series of small contrast injections is then administered (e.g., in the case of CT, a series of up to fifteen 10-mL doses of 300 mgI/mL water-soluble contrast agent). Scans are performed at desired, appropriate post-injection times (e.g., determined based on the test injections), and contrast enhancement in the target region is determined using, for example, a region of interest (ROI) to track any of a number of parameters (including, but not limited to, attenuation (Hounsfield units [HU] for CT), signal (MRI), echogenicity (ultrasound), etc.). The imaging data is not limited to the particular format presented. In some embodiments, imaging data is displayed as a color-coded or grayscale map or overlay of changes in attenuation/signal/echoicity, differences between target and non-target tissue, differences in contrast agent arrival times during treatment, changes in tissue perfusion, and any other tissue properties that can be measured before and after contrast injection. The methods of the present invention are not limited to a selected ROI but can be extended to all pixels in any image. These pixels can be color-coded or overlaid to show where tissue changes have occurred and are occurring. These pixels can change color (or other properties) as tissue properties change, providing a near-real-time display of treatment progress. This approach can also be extended to three-dimensional/four-dimensional image display methods.

In some embodiments, the area to be treated is displayed on a computer overlay, and a second overlay of a different color or shade produces a near-real-time display of treatment progress. In some embodiments, this display and imaging is automated, creating a feedback loop for the treatment technology (radiofrequency, microwave, high-intensity focused ultrasound, laser, cryotherapy, etc.) to modulate power based on imaging findings. For example, if perfusion to the target area drops below a target level, power can be reduced or stopped. These embodiments are applicable, for example, to multiple applicator systems, as power, time, frequency, duty cycle, etc., are modulated for each individual applicator or element in a phased array system to create a precisely contoured zone for tissue treatment. Conversely, in some embodiments, this approach is used to select areas to be avoided (e.g., delicate structures to be avoided, such as bile ducts or intestine). In such embodiments, the approach monitors tissue changes in the areas to be avoided and uses an alarm (e.g., visible light and/or audible alarm) to alert the user (e.g., the treating physician) that structures to be avoided are at risk of damage. In some embodiments, this feedback loop is used to modify power or any other parameters to avoid continued damage to tissue areas selected for avoidance. In some embodiments, protection of tissue regions from ablation is achieved by setting a threshold, such as a target ROI in a vulnerable region, or using a computer overlay to define a user desired "no-treat" zone.

Tuning system

In some embodiments, the energy delivery systems of the present invention utilize tuning elements to adjust the amount of energy delivered to a tissue region. In some embodiments, the tuning elements are manually adjusted by the user of the system. In some embodiments, the tuning system is incorporated into the energy delivery device to allow the user to adjust the device's energy delivery as desired (see, e.g., U.S. Patent Nos. 5,957,969 and 5,405,346; each of which is incorporated herein by reference in its entirety). In some embodiments, the device is pre-tuned to the desired tissue and remains fixed throughout the procedure. In some embodiments, the tuning system is designed to match the impedance between the generator and the energy delivery device (see, e.g., U.S. Patent No. 5,364,392; incorporated herein by reference in its entirety). In some embodiments, the tuning element is automatically adjusted and controlled by a processor of the present invention (see, e.g., U.S. Patent No. 5,693,082; incorporated herein by reference in its entirety). In some embodiments, the processor adjusts energy delivery over time to provide a constant amount of energy throughout the procedure, taking into account any number of desired factors, including but not limited to heat, the nature and/or location of the target tissue, the size of the anticipated lesion, the duration of treatment, proximity to sensitive organ regions or blood vessels, and the like. In some embodiments, the system includes sensors that provide feedback to a user or a processor that monitors the function of the device continuously or at certain points in time. The sensors can record and/or report any number of properties, including but not limited to heat at one or more locations of system components, heat at tissue, properties of tissue, etc. The sensors can be in the form of imaging devices such as CT, ultrasound, magnetic resonance imaging, or any other imaging device. In some embodiments, particularly for research applications, the system records and stores information that is generally used for future optimization of the system and/or for optimization of energy delivery under specific conditions (e.g., patient type, tissue type, size and shape of the target area, location of the target area, etc.).

Temperature control system

In some embodiments, the energy delivery systems of the present invention utilize a coolant system to reduce heating within and along an energy delivery device (e.g., a tissue ablation catheter). The systems of the present invention are not limited to a particular cooling system mechanism. In some embodiments, the system is designed to circulate a coolant (e.g., air, liquid, etc.) throughout the energy delivery device, thereby reducing the temperature of the coaxial transmission line and antenna. In some embodiments, the system utilizes an energy delivery device having a channel designed to circulate the coolant. In some embodiments, the system provides a cooling sheath that wraps around the antenna or a portion of the antenna for external cooling (see, e.g., U.S. Patent Application No. 11/053,987; incorporated herein by reference in its entirety). In some embodiments, the system utilizes an energy delivery device with a conductive covering surrounding the antenna to limit heat loss to surrounding tissue (see, e.g., U.S. Patent No. 5,358,515; incorporated herein by reference in its entirety). In some embodiments, after the coolant circulates, it is output, for example, to a waste container. In some embodiments, after the coolant circulates, it is recirculated. In some embodiments, the coolant is a gas that circulates at or near its critical point. In some embodiments, the gas delivered at or near its critical point is carbon dioxide gas. In some embodiments, the energy delivery device is configured to compress the delivered coolant (e.g., carbon dioxide gas at or near its critical point) at a desired pressure to maintain the coolant at or near its critical point.

In some embodiments, the system utilizes an inflatable balloon in conjunction with an energy delivery device to push tissue away from the surface of the antenna (see, eg, US Patent Application No. 11/053,987; herein incorporated by reference in its entirety).

In some embodiments, the system utilizes a device configured to attach to an energy delivery device to reduce unwanted heating within and along the energy delivery device (see, eg, US Patent Application No. 11/237,430; herein incorporated by reference in its entirety).

Signage system

In some embodiments, the energy delivery systems of the present invention utilize an identification element (e.g., an RFID element, an identification ring (e.g., a fiducial), a barcode, etc.) associated with one or more components of the system. In some embodiments, the identification element conveys information about a specific component of the system. The present invention is not limited to the information conveyed. In some embodiments, the information conveyed includes, but is not limited to, the type of component (e.g., manufacturer, size, energy level, tissue structure, etc.), whether the component has been used before (e.g., to ensure that non-sterile components are not used), the location of the component, patient-specific information, etc. In some embodiments, this information is read by a processor of the present invention. In some such embodiments, the processor configures other components of the system to work with or optimize for the component containing the identification element.

In some embodiments, the energy delivery device includes one or more markings (e.g., scratches, color schemes, etchings (e.g., laser etching), painted contrast markers, identifying rings (e.g., fiducials), and/or ridges) to enhance identification of a particular energy delivery device (e.g., to enhance recognition of a particular device near other devices of similar appearance). These markings are particularly useful when multiple devices are inserted into a patient. In such situations, particularly where the devices may intersect at various angles, it can be difficult for the treating physician to correlate which proximal end of a device outside the patient's body is associated with which distal end of a corresponding device inside the patient's body. In some embodiments, a marking (e.g., a number) is present on the proximal end of the device so that it is visible to the physician's eye, while a second marking (e.g., corresponding to the number) is present on the distal end of the device so that it is visible to imaging equipment when inserted into the body. In some embodiments employing a set of antennas, the individual members of the set are numbered (e.g., 1, 2, 3, 4, etc.) on both the proximal and distal ends. In some embodiments, the handle is numbered, and matching numbered detachable (e.g., disposable) antennas are attached to the handle prior to use. In some embodiments, the system's processor ensures that the handle and antenna are correctly matched (e.g., via an RFID tag or other means). In some embodiments where the antenna is a disposable device, the system provides a warning if an attempt is made to reuse the disposable component when it should have been discarded. In some embodiments, the marking improves identification in any type of detection system, including but not limited to MRI, CT, and ultrasound.

The energy delivery system of the present invention is not limited to a particular type of tracking device. In some embodiments, GPS and GPS-related devices are used. In some embodiments, RFID and RFID-related devices are used. In some embodiments, barcodes are used.

In such embodiments, prior to using a device having an identification element, authorization (e.g., entry of a code, scanning of a barcode) is required prior to using the device. In some embodiments, the information element identifies that some components have been used previously and sends information to the processor to lock out (e.g., prevent) use of the system until new sterile components are provided.

Temperature monitoring system

In some embodiments, the energy delivery systems of the present invention utilize a temperature monitoring system. In some embodiments, the temperature monitoring system is used to monitor the temperature of the energy delivery device (e.g., via a temperature sensor). In some embodiments, the temperature monitoring system is used to monitor the temperature of a tissue region (e.g., the tissue being treated, surrounding tissue). In some embodiments, the temperature monitoring system is designed to communicate with a processor to provide temperature information to a user or the processor, allowing the processor to appropriately adjust the system. In some embodiments, the temperature monitored at multiple points along the antenna is used to estimate ablation status, cooling status, or for safety checks. In some embodiments, the temperature monitored at multiple points along the antenna is used to determine, for example, the geographic characteristics of the ablation zone (e.g., diameter, depth, length, density, width, etc.) (e.g., based on the tissue type and the amount of power used in the energy delivery device). In some embodiments, the temperature monitored at multiple points along the antenna is used to determine, for example, the status of a procedure (e.g., the end of a procedure). In some embodiments, temperature is monitored using thermocouples or electromagnetic devices that pass through the interstitial antenna.

Programming device hub

The systems of the present invention may also utilize one or more additional components that directly or indirectly utilize or assist with the features of the present invention. For example, in some embodiments, one or more monitoring devices are used to monitor and/or report on the function of any one or more components of the system. Furthermore, any medical device and system that can be used directly or indirectly in conjunction with the devices of the present invention may be included in the system. These components include, but are not limited to: sterilization systems, devices, and components; other surgical, diagnostic, or monitoring devices or systems; computer equipment, manuals, instructions, labels, and guides; robotic equipment, and the like.

In some embodiments, the system utilizes pumps, containers, pipes, wiring, and/or other components that provide connectivity between the various components of the system. For example, any type of pump can be used to supply gaseous or liquid coolant to the antenna of the present invention. Gas or liquid handling tanks containing the coolant can be used in the system. In some embodiments, multiple tanks (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, etc.) can be used simultaneously or sequentially as needed. In some embodiments, more than one tank is used so that when one tank becomes empty, additional tanks are automatically used to prevent program interruption (e.g., when one _CO2 tank is empty, a second _CO2 tank is automatically used to prevent program interruption). In some embodiments using _CO2 , a standard E-sized _CO2 cylinder is used to supply the _CO2 .

In some embodiments, the system utilizes one or more external heating devices. The system is not limited to a specific use of the external heating devices. In some embodiments, the external heating devices are used to maintain certain system components within a specific temperature range. For example, in some embodiments, the external heating devices are used to maintain a gas or liquid processing tank (e.g., a tank containing _CO2 ) that provides coolant to one or more devices within a specific temperature range. In fact, in some embodiments, the external heating devices prevent the natural temperature drop of the tank upon release of its contents, thereby ensuring that the coolant provided to the devices is at a constant temperature or temperature range. The system is not limited to a specific external heating device. The external heating devices are not limited to a specific method for maintaining the temperature within a specific range. In some embodiments, the external heating devices maintain the pressure within a gas or liquid processing tank (e.g., a tank containing _CO2 ) within a specific range (e.g., heating a tank containing _CO2 (e.g., a standard E-size CO2 cylinder) at a pressure of ₁₀₀₀ psi to maintain the pressure of the _CO2 released from it at 850 psi).

In certain embodiments, the energy delivery system (e.g., energy delivery device, processor, power supply, imaging system, temperature regulation system, temperature monitoring system, and/or identification system) and all associated energy delivery system utility sources (e.g., cables, wires, power cords, tubing, tubes for providing energy, gases, coolants, liquids, pressure, and communication substances) are provided in a manner that reduces undesirable display issues (e.g., tangling, clutter, and sterility compromise associated with unorganized energy delivery system utility sources). The present invention is not limited to a particular manner of providing the energy delivery system and energy delivery system utility sources to reduce undesirable display issues. In certain embodiments, as shown in FIG13 , the energy delivery system and energy delivery system utility sources are organized into an inlet/outlet box 1300, a transport sheath 1310, and a procedure device pod 1320. In certain embodiments, the energy delivery system and energy delivery system utility sources organized into an inlet/outlet box, a transport sheath, and a procedure device pod provide several benefits. These benefits include, but are not limited to, reducing the number of wires that traverse between the generator (e.g., microwave generator) and the patient (e.g., reducing the number of wires on the floor), keeping the sterile environment and operating room uncluttered, increasing patient safety by allowing the energy delivery system to "move" with the patient to prevent device displacement (e.g., antenna displacement), increasing power transfer efficiency by reducing the distance energy travels within the energy delivery device, and reducing disposable costs by shortening the length of the disposable cable.

The present invention is not limited to a particular type or class of inlet/outlet boxes. In some embodiments, the inlet/outlet box contains a power source and a coolant supply. In some embodiments, the inlet/outlet box is located outside the sterile field in which the patient is receiving treatment. In some embodiments, the inlet/outlet box is located outside the room in which the patient is receiving treatment. In some embodiments, the inlet/outlet box is located in the room in which the patient is receiving treatment and maintained in a sterile manner. In some embodiments, one or more cables connect the inlet/outlet box to the procedure device pod. In some embodiments, a single cable (e.g., a transport sheath) is used. For example, in some such embodiments, the transport sheath contains components for transporting power and coolant to and from the inlet/outlet box. In some embodiments, the transport sheath connects to the procedure device pod without creating a physical obstruction for the physician (e.g., being routed under the floor or mounted overhead). In some embodiments, the cable is a low-loss cable (e.g., a low-loss cable connecting the power source to the procedure device hub). In some embodiments, the low-loss cable is secured (e.g., to the procedure device hub, to the procedure table, or to the ceiling) to prevent injury from accidental cable tugs. In some embodiments, the cable connecting the power generator (e.g., a microwave power generator) and the procedure device hub is a low-loss, reusable cable. In some embodiments, the cable connecting the procedure device hub to the energy delivery device is a flexible, disposable cable. In some embodiments, the cable connecting the procedure device hub to the energy delivery device has high flexibility and "memory" properties (e.g., the cable can be shaped to remain in one or more desired positions). In some embodiments, the cable connecting the procedure device hub to the energy delivery device is a silicone-coated fiberglass cable.

The present invention is not limited to a particular type or class of procedure device pods. In some embodiments, the procedure device pod is configured to receive power, coolant, or other elements from an inlet/outlet box or other source. In some embodiments, the procedure device pod provides a control center physically located near the patient for any one or more of: delivering energy to the medical device, circulating coolant to the medical device, collecting and processing data (e.g., imaging data, energy delivery data, safety monitoring data, temperature data, etc.), and providing any other functions that facilitate the medical procedure. In some embodiments, the procedure device pod is configured to engage a transport sheath to receive associated energy delivery system utility sources. In some embodiments, the procedure device pod is configured to receive and distribute various energy delivery system utility sources to applicable devices (e.g., energy delivery devices, imaging systems, temperature regulation systems, temperature monitoring systems, and/or identification systems). For example, in some embodiments, the procedure device pod is configured to receive microwave energy and coolant from an energy delivery system utility source and distribute the microwave energy and coolant to the energy delivery device. In some embodiments, the procedure device pod is configured to enable or disable, calibrate, and adjust (e.g., automatically or manually) the quantity of specific energy delivery system utility sources as needed. In some embodiments, the procedure device pod includes a power divider for adjusting (e.g., manually or automatically turning on, off, or calibrating) the number of specific energy delivery system utility sources as needed. In some embodiments, the procedure device pod includes software designed to provide the energy delivery system utility sources in a desired manner. In some embodiments, the procedure device pod includes a display area that indicates the relevant characteristics of each energy delivery system utility source (e.g., which devices are currently in use/not in use, the temperature of a specific body region, the amount of gas in a specific _CO2 tank, etc.). In some embodiments, the display area is touch-enabled (e.g., a touchscreen). In some embodiments, a processor associated with the energy delivery system is located in the procedure device pod. In some embodiments, a power supply associated with the energy delivery system is located in the procedure device pod. In some embodiments, the procedure device pod includes sensors configured to automatically inhibit one or more energy delivery system utility sources in the event of an undesirable event (e.g., undesirable heating, undesirable leakage, undesirable pressure change, etc.). In some embodiments, the procedure device pod is lightweight enough to be placed on a patient without causing discomfort and/or injury to the patient (e.g., less than 15 pounds, less than 10 pounds, less than 5 pounds).

The procedure device pod of the present invention is not limited to a specific application or use in a specific facility. In fact, the procedure device pod is designed for use in any setting where energy can be transmitted. These uses include any and all medical, veterinary, and research applications. In addition, the procedure device pod can be used in agricultural facilities, manufacturing facilities, mechanical facilities, or any other application where energy is to be delivered. In some embodiments, the procedure device pod is used in medical procedures where patient mobility is not restricted (e.g., CT scans, ultrasound imaging, etc.).

In some embodiments, the procedure device pod is designed to be positioned in a sterile facility. In some embodiments, the procedure device pod is positioned on the patient's bed (e.g., on the bed itself, on a bed rail), on a table the patient rests on (e.g., a table used for CT, ultrasound, MRI, etc.), or on another structure near the patient (e.g., a CT gantry). In some embodiments, the procedure device pod is positioned on a separate table. In some embodiments, the procedure device pod is attached to the ceiling. In some embodiments, the procedure device pod is attached to the ceiling so that the user (e.g., a physician) can move it to a desired location (thus avoiding the need to position energy delivery system utility sources (e.g., cables, wires, power cords, tubing, and tubes providing energy, gas, coolant, fluid, pressure, and connectivity) on or near the patient's body during use). In some embodiments, the procedure device hub is positioned to rest on the patient's body (e.g., the patient's calf, thigh, waist, or chest). In some embodiments, the procedure device hub is positioned above the patient's head or below the patient's feet. In some embodiments, the procedure device hub has Velcro that allows for attachment to a desired area (eg, a procedure table, the patient's drape and/or clothing).

In some embodiments, the procedure device hub is configured to be attached to a strip (e.g., a CT safety belt) for medical procedures. In some embodiments, the procedure belt is attached to a procedure table (e.g., a CT table) (e.g., by grooves on both sides of the procedure table, by Velcro, by adhesive, by suction) and is used to secure the patient to the procedure table (e.g., by wrapping around the patient and connecting with, for example, Velcro). The procedure device hub is not limited to a specific manner of attachment to the procedure belt. In some embodiments, the procedure device hub is attached to the procedure belt. In some embodiments, the procedure device hub is attached to an independent strip that allows replacement of the procedure belt. In some embodiments, the procedure device hub is attached to an independent strip that is configured to be attached to the procedure belt. In some embodiments, the procedure device hub is attached to an independent strip that is configured to be attached to any area of the procedure table. In some embodiments, the procedure device hub is attached to an independent strip that has insulation and/or padding to ensure the patient's comfort. Figure 18 shows a procedure device hub connected to a procedure table belt.

In some embodiments, the procedure device hub is configured to attach to a procedure ring. The present invention is not limited to a particular type or kind of procedure ring. In some embodiments, the procedure ring is configured to be placed around the patient (e.g., around the patient's torso, head, feet, arms, etc.). In some embodiments, the procedure ring is configured to attach to a procedure table (e.g., a CT table). The procedure device ring is not limited to a particular shape. In some embodiments, the procedure device ring is, for example, oval, circular, rectangular, rhombus-shaped, etc. In some embodiments, the procedure device ring is approximately half a ring (e.g., 25% ring, 40% ring, 45% ring, 50% ring, 55% ring, 60% ring, 75% ring). In some embodiments, the procedure ring is, for example, metal, plastic, graphite, wood, ceramic, or any combination thereof. The procedure device hub is not limited to a particular method of attachment to the procedure ring. In some embodiments, the procedure device hub is attached to the procedure ring (e.g., via Velcro, via a buckle assembly, via an adhesive). In some embodiments utilizing a low-loss cable, the low-loss cable is additionally attached to the procedure ring. In some embodiments, the size of the procedure ring can be adjusted (e.g., retracted, extended) to accommodate the size of the patient. In some embodiments, additional items can be attached to the procedure ring. In some embodiments, the procedure ring can be easily moved into and out of the vicinity of the patient.

In some embodiments, the procedure device hub is configured to attach to a custom sterile drape. The present invention is not limited to a particular type or kind of custom sterile drape. In some embodiments, the custom sterile drape is configured to be placed on the patient's body (e.g., on the patient's torso, head, feet, arms, entire body, etc.). In some embodiments, the custom sterile drape is configured to attach to a procedure table (e.g., a CT table). The custom sterile drape is not limited to a particular shape. In some embodiments, the custom sterile drape is, for example, oval, circular, rectangular, or a diagonal grid. In some embodiments, the custom sterile drape is shaped to accommodate a specific area of the patient's body. In some embodiments, the procedure ring is, for example, cloth, plastic, or any combination thereof. The procedure device hub is not limited to a particular method of attaching to the custom sterile drape. In some embodiments, the procedure device hub is attached to the custom sterile drape (e.g., via Velcro, a buckle assembly, an adhesive, or a clamp (e.g., an alligator clip)). In some embodiments utilizing a low-loss cable, the low-loss cable is attached to the custom sterile drape. In some embodiments, additional objects can be attached to the custom sterile drape. In some embodiments, the custom sterile drape can be easily moved near the patient and removed from the patient. In some embodiments, the custom sterile drape has one or more fenestrations for performing medical procedures. Figure 19 shows a custom sterile drape with fenestrations and cables inserted through the fenestrations. Figure 20 shows an energy delivery system of the present invention, which has a generator connected to a procedure device hub via a cable, wherein the procedure device hub is secured to a procedure table (e.g., by a procedure table strap). In addition, as shown in Figure 20, the custom sterile drape is positioned on a patient lying on a procedure table, wherein the custom sterile drape has a fenestration.

In some embodiments, the procedure device hub is configured to have legs so that the hub can be positioned near the patient. In some embodiments, the procedure device hub has adjustable legs (e.g., to allow the procedure device hub to be positioned in a variety of positions). In some embodiments, the procedure device hub has three adjustable legs to allow the device to be positioned in a variety of tri-pod positions. In some embodiments, the legs have Velcro to allow attachment to a desired area (e.g., a procedure table, a patient's drape, and/or clothing). In some embodiments, the legs are formed of an elastic material that is configured to form an arc over a procedure table (e.g., a CT table) and squeeze the railing of the procedure table. In some embodiments, the legs are configured to attach to the railing of the procedure table.

In some embodiments, the procedure device pod is configured to communicate (wirelessly or via wire) with a processor (e.g., a computer, via the internet, via a cell phone, or via a PDA). In some embodiments, the procedure device hub can be operated via a remote control. In some embodiments, the procedure device hub has one or more lights. In some embodiments, when power flows from the procedure device hub to the energy delivery device, the procedure device hub provides a detectable signal (e.g., auditory, visual (e.g., a pulsing light)). In some embodiments, the procedure device hub has an auditory input (e.g., an MP3 player). In some embodiments, the procedure device hub has a speaker for providing sound (e.g., sound from an MP3 player). In some embodiments, the procedure device hub has an auditory output for providing sound to an external speaker system. In some embodiments, the use of a procedure device pod allows for the use of shorter cables, wires, power cords, tubing, and/or conduits (e.g., less than 4 feet, 3 feet, or 2 feet). In some embodiments, the procedure device pod and/or one or more components connected thereto, or a portion thereof, are covered by a sterile sheath. In some embodiments, the procedure device hub has a power amplifier for supplying power (eg, to an energy delivery device).

In some embodiments, the delivery device cartridge is configured to compress the transported coolant (e.g., _CO2 ) to any desired pressure, for example, to maintain the coolant at a desired pressure (e.g., the gas's critical point) to improve cooling or temperature maintenance. For example, in some embodiments, the gas is provided at or near its critical point to maintain the temperature of the device, pipeline, cable, or other component at or near a constant, defined temperature. In some such embodiments, the component itself is not cooled, i.e., its temperature does not drop from a starting temperature (e.g., room temperature), but rather is maintained at a constant temperature that is lower than the temperature the component would have been at without intervention. For example, _CO2 can be used at or near its critical point (e.g., 31.1 degrees Celsius at 78.21 kPa) to maintain a temperature that keeps the system's components cool enough to avoid burning tissue, but also not cooled or maintained significantly below room temperature or body temperature to freeze or frostbite skin contacting the components. Using this configuration allows for the use of less insulation, as there are no "cold" components that must be shielded from the human body or the surrounding environment. In some embodiments, the procedure device pod includes a retracted element designed to backflush used and/or unused cables, wires, power cords, tubing, and tubes that provide energy, gases, coolants, liquids, pressure, and communication materials. In some embodiments, the procedure device pod is configured to fill coolant for distribution, for example, to an energy delivery device, such that the coolant is at a desired temperature prior to use of the energy delivery device. In some embodiments, the procedure device pod includes software configured to fill coolant for distribution, for example, to an energy delivery device, such that the system is at a desired temperature prior to use of the energy delivery device. In some embodiments, circulation of the coolant at or near a critical point allows cooling of electronic components of the energy delivery device without the need for an additional cooling mechanism (e.g., a fan).

In one illustrative embodiment, an import/export box contains one or more microwave power sources and a coolant supply (e.g., pressurized carbon dioxide gas). The import/export box is connected to a single transport jacket that delivers the microwave energy and coolant to the procedure device pod. The coolant lines or power lines within the transport jacket can be intertwined to maximize cooling of the transport jacket itself. The transport jacket extends along the floor into the sterile field where the procedure is performed, in a position that does not hinder the movement of the medical team caring for the patient. The transport jacket is connected to a table located near the imaging table on which the patient lies. The table is portable (e.g., on wheels) and can be connected to the imaging table for movement. The table includes an arm that can be flexible or retractable to allow the arm to be positioned above and above the patient. The transport jacket or a cable connected to the transport jacket extends along the arm to a position overhead. At the end of the arm is the procedure device pod. In some embodiments, two or more arm members are provided with two or more procedure device pods or two or more subassemblies of a single procedure device pod. The procedure device pod is small (e.g., less than 1 cubic foot, less than 10 cubic centimeters, etc.) to facilitate movement and positioning above the patient. The procedure device pod contains a processor for controlling all computing aspects of the system. The device pod contains one or more connection ports for connecting cables leading to the energy delivery device. The cables are connected to the ports. The cables are retractable and less than three feet in length. Using short cables reduces costs and prevents power loss. When not in use, the cables hang in the air above the patient and do not come into contact with the patient's body. The ports are configured to have dummy loads when not in use (e.g., when the energy delivery device is not connected to a particular port). The procedure device pod is within reach of the treating physician so that computer controls can be adjusted and displayed information can be viewed in real time during the procedure.

In some embodiments, the energy delivery system utilizes a procedure cart to maintain system components within a single area. For example, in some embodiments, the system provides a procedure cart configured to store a cooling source (e.g., multiple tanks supplying gas or liquid coolant to the devices of the present invention) (e.g., standard E-sized _CO2 cylinders) for device cooling purposes, as well as an external heating device to maintain the coolant source at a desired pressure, one or more power sources, one or more associated energy delivery system utility sources (e.g., cables, wires, power cords, tubing, and tubes for providing energy, gas, coolant, liquid, pressure, and connectivity), and/or a procedure device hub. Indeed, the procedure cart is not limited to a particular design or purpose. In some embodiments, the procedure cart is configured for use within a sterile setting (e.g., an operating room) and contains a cooling tank, associated external heating device, and a procedure device pod/hub. In some embodiments, the procedure cart is configured for use only in non-sterile settings. In some embodiments, the procedure cart is configured for easy mobility (e.g., it is designed with wheels). The procedure cart is configured to connect to any component of the energy delivery system of the present invention (e.g., the inlet/outlet box, the transport sheath, and/or the procedure device hub). In some embodiments, the procedure cart includes a display area (e.g., user interface software) for operating and/or monitoring the components of the energy delivery system. In some embodiments, the procedure cart is configured to communicate (wirelessly or via wire) with a processor (e.g., a computer, via the internet, via a cell phone, via a PDA). In some embodiments, the procedure cart is configured to send and receive (wirelessly or via wire) information related to the energy delivery system (e.g., the number of uses for each component, which devices are currently being used, etc.).

Uses of energy delivery systems

The systems of the present invention are not limited to a particular application. In fact, the energy delivery systems of the present invention are designed for use in any setting where energy delivery is appropriate. These uses include any and all medical, veterinary, and research applications. Furthermore, the systems and devices of the present invention may be used in agricultural settings, manufacturing facilities, machinery facilities, or any other application where energy delivery is desired.

In some embodiments, the system is configured for open, percutaneous, intravascular, intracardiac, endoscopic, laparoscopic, intracavitary, or surgical energy delivery. In some embodiments, the energy delivery device can be positioned within the patient's body via a catheter, through a surgically extended opening, and/or through a body orifice (e.g., mouth, ear, nose, eye, vagina, penis, anus) (e.g., N.O.T.E.S. procedure). In some embodiments, the system is configured for delivering energy to a target tissue or area. In some embodiments, a positioning plate is provided to enhance percutaneous, intravascular, intracardiac, laparoscopic, and/or surgical energy delivery via the energy delivery system of the present invention. The present invention is not limited to a particular type and/or class of positioning plates. In some embodiments, the positioning plate is designed to position one or more energy delivery devices at a desired body area for percutaneous, intravascular, intracardiac, laparoscopic, and/or surgical energy delivery. In some embodiments, the positioning plate's composition prevents exposure of the body area to undesirable heat from the energy delivery system. In some embodiments, the plate provides guides to assist in positioning the energy delivery device. The present invention is not limited by the nature of the target tissue or area. Uses include, but are not limited to, treatment of cardiac arrhythmias, tumor ablation (benign and malignant), bleeding control during surgery, bleeding control after trauma, any other bleeding control, soft tissue removal, tissue resection and harvesting, treatment of varicose veins, intracavitary tissue ablation (e.g., for the treatment of esophageal diseases such as Bartholin's esophagus and esophageal adenocarcinoma), bone tumors, treatment of normal bone and benign bone conditions, intraocular applications, cosmetic surgical applications, treatment of central nervous system disorders including brain tumors and electrical disturbances, sterilization procedures (e.g., fallopian tube removal), and cauterization of blood vessels or tissue for any purpose. In some embodiments, surgical applications include ablative therapies (e.g., to achieve coagulative necrosis). In some embodiments, surgical applications include tumor ablation of targets such as metastatic tumors. In some embodiments, the device is configured to be moved and positioned at any desired location, including but not limited to the brain, neck, chest, abdomen, and pelvis, with minimal damage to tissue or organism. In some embodiments, the system is configured for guided delivery, for example, via computed tomography, ultrasound, magnetic resonance imaging, fluoroscopes, and the like.

In certain embodiments, the present invention provides a method for treating a tissue region, comprising: providing a tissue region and a system described herein (e.g., an energy delivery device, and at least one of the following components: a processor, a power supply, a device for directing, controlling, and transmitting power (e.g., a power splitter), a temperature monitor, an imager, a tuning system, and/or a cooling system); positioning a portion of the energy delivery device in proximity to the tissue region, and delivering an amount of energy to the tissue region using the device. In some embodiments, the tissue region is a tumor. In some embodiments, the delivery of energy results in, for example, ablation of a thrombus in the tissue region and/or a blood vessel and/or electroporation of the tissue region. In some embodiments, the tissue region is a tumor. In some embodiments, the tissue region comprises one or more of the following: heart, liver, genitals, stomach, lung, large intestine, small intestine, brain, neck, bone, kidney, muscle, tendon, blood vessel, prostate, bladder, and spinal cord.

experiment

Example I

This example demonstrates the avoidance of undesirable tissue heating by using the energy delivery device of the present invention that circulates coolant through the coolant channel. For all experiments, the ablation needle shaft was 20.5 cm. There was minimal cooling of the handle assembly indicating that the handle cooling effect was well isolated. Temperature probes 1, 2 and 3 were located 4 cm, 8 cm and 12 cm near the tip of the stainless steel needle, respectively (see Figure 9). Temperature measurements were taken for 35% power measurements after insertion into a porcine liver and for 45% power measurements after insertion into a porcine liver. For the 35% power measurement, probe 4 was on the handle itself. For the 45% power measurement, probe 4 was located at the needle-skin interface, approximately 16 cm back from the stainless steel needle tip.

As shown in FIG10 , treatment at 35% power for 10 minutes with an anonymous high (6.5%) reflected power demonstrated maintenance of the device at a non-tissue damaging temperature at probes 1, 2, 3, and the handle.

As shown in Figure 11, treatment with an anonymous high (6.5%) reflected power at 45% power for 10 minutes demonstrated that the device maintained a non-tissue damaging temperature at probes 1, 2, 3, and 4. Observation of the skin and fat layers after 10 minutes of ablation with an anonymous high (6.5%) reflected power at 45% power showed no obvious burns or thermal damage.

Example II

This example demonstrates generator calibration. Generator calibration is performed at the factory by Cober-Muegge and is set for maximum accuracy for powers greater than 150 W. The magnetron behaves much like a diode: increasing the cathode voltage does not increase the vacuum current (which is proportional to the output power) until a critical threshold is reached, at which point the vacuum current increases rapidly with voltage. Control of this magnetron source relies on precise control of the cathode voltage near this critical point. Therefore, the generator is not specified for powers from 0-10%, and the correlation between the output power and the percentage of theoretical input power is less than 15%.

To test the generator calibration, the power dial was varied from 0.25% in 1% increments (equivalent to a theoretical output power of 0-75 W in 3-W increments), and the generator's output power display was recorded and the power output measured. The measured output power was adjusted for the measured losses of the coaxial cable, coupler, and load at room temperature. The output display was also adjusted for offset error (i.e., the generator read 2.0% when the dial was set to 0%).

The error between the dial and the generator output power display is larger for low power dial settings. For dial settings above 15%, the two values converge quickly to a percentage error of less than 5%. Similarly, for dial settings below 15%, the measured output power differs significantly from the theoretical output power, but is more accurate for dial settings above 15%.

Example III.

This example describes the installation and testing of an antenna during manufacturing. This provides a method for installation and testing in a manufacturing environment. This method uses a liquid tissue-equivalent phantom instead of tissue.

Based on numerical calculations and experimental measurements performed on the antenna, it is known that a change of approximately 1 mm in L2 will cause the reflected power to increase from less than approximately 30 dB to approximately 20-25 dB. Changes in tissue properties during the ablation process likely make this increase less significant, so we believe a relative tolerance of 0.5 mm on length L2 is reasonable. Similarly, a tolerance of 0.5 mm is used on length L1, even though the total reflection coefficient depends more on L2 than on L1.

Testing antenna tuning for quality control purposes can be accomplished using a liquid solution designed to simulate the dielectric properties of the liver, lungs, and kidneys (see, e.g., Guy AW (1971) IEEE Trans. Microw. Theory Tech. 19:189–217; incorporated herein by reference in its entirety). The antenna is immersed in the mannequin, and the reflection coefficient is recorded using a single-port measurement setup or a full vector network analyzer (VNA). A reflection coefficient below 30 dB is selected for verification to ensure proper tuning.

Example IV

This example compares the efficiency, heating capabilities, and manufacturability of a triaxial antenna and a center-fed dipole antenna. Creating a stiffer, sharper tip that could be easily inserted required modifications to the original triaxial design. Computer modeling was initially used to determine what changes to the antenna length might be required to add an alumina sheath and a faceted metal tip. After modeling confirmed that the antenna would need to be extended and that the metal tip would not degrade performance, the antenna was constructed for testing in in vitro liver tissue. This testing demonstrated that the modified design retained its high efficiency while providing sufficient mechanical strength for percutaneous placement. Computer modeling of the center-fed dipole design yielded marginal results, and subsequent device processing proved difficult to replicate. Therefore, an insertable triaxial device was selected as the lead antenna design.

Computer modeling indicated that the thermally resistive coating and severe thermal degradation could reduce the amount of heat allowed to flow from the distal antenna tip to the proximal portion of the antenna. However, an effective water cooling solution was able to increase the power output of the 0.020” coaxial cable from approximately 8 W to over 150 W. Water cooling also eliminated any heating of the shaft extending proximally from the antenna tip when using 150 W of input power (Figure 21). However, this implementation required the use of expensive 0.020” coaxial cable to provide sufficient water flow rate (approximately 30 ml/min). Additionally, the 0.020” cable had two to three times the losses of the previously used 0.047” cable, which reduced power output by as much as 15 W and required cooling for this additional power consumption. The final antenna design, which included a PEEK sheath surrounding the entire assembly, reduced the potential for bonding between the metal antenna and surrounding tissue, while also providing a thermal buffer that was shown to reduce thermal conduction heating.

The study was conducted percutaneously using either a cooled 17-gauge prototype antenna or a 17-gauge cooled RF electrode from Valleylab/Covidien to create ablations in a normal in vivo porcine lung model. Ablations were performed for 10 minutes using the clinical standard of 200 W with impedance control for the RF group and 135 W for the microwave group. Ablations created in the microwave group were significantly larger than those in the RF group, with mean ablation diameters of 3.32 ± 0.19 cm and 2.7 ± 0.27 cm, respectively (P < .0001, Figure 9). The circularity of the ablations was also significantly greater in the microwave group than in the RF group (0.90 ± 0.06 vs. 0.82 ± 0.09, P < .05). No major complications were observed throughout the study. A minor pneumothorax was observed in one animal during two ablations, both in the RF group. Both remained stable without intervention. This study concluded that microwaves heat lung tissue more effectively and generally more rapidly than RF current.

Example V

This example studies cooling in a simulated heating environment. The heater coil is threaded with a 17-gauge stainless steel needle, nearly equivalent to the third conductor of a triaxial antenna. Four thermocouples are placed along the outside of the needle, and the entire system is thermally insulated with closed-cell foam. This setup is considered a worst-case scenario, as the high thermal conductivity of blood flow and biological tissue will tend to provide some antenna cooling. The coil is heated with a power of 0-50 W, and the temperature is recorded using NC- _CO₂ at a flow rate of 0-10 stp L/min. Test results indicate that a moderate _CO₂ flow rate is sufficient to cool the entire 50 W input power, maintaining the heated tube at ambient temperature (Figure 24).

Temperatures exceeding 100°C were recorded on the outer surface of the needle in the absence of cooling, but cooling with 10-20 stp L/min of NC- _CO2 reduced the surface temperature to below 30°C (Figure 24). These tests indicate that a moderate amount of NC- _CO2 (approximately 10 stp L/min) can effectively cool up to 50 W of power from the inner side of the ablation antenna.

Example VI.

This experiment measures the effect of heat conduction from the heated antenna tip to the proximal end. A modified antenna (which replaces the ceramic heat sink with a heat-conducting copper tube) is placed inside an electric heater with thermal paste to ensure good thermal contact between the heater and the antenna (Figure 25). Thermocouples are placed at several points along the antenna's outer surface to measure the relationship between temperature and NC- _CO₂ flow rate.

Before cooling, the temperature along the outer conductor exceeded 80°C within 1 cm of the heater. When cooling was initiated at even a modest rate of 13 stp L/min, the temperature dropped to the input temperature of the NC- _CO₂ gas: approximately 0°C (Figure 25). Increasing the flow rate further lowered the temperature. The gas was slightly precooled in a heat exchanger to test the possibility of a "bonding" function on the needle shaft, similar to that employed in cryoablation probes. This precooling resulted in a near-critical operating temperature of 31°C below the desired level, and additional implementations were beyond the scope of this investigation.

Follow-up tests using the same facilities and heaters were also performed to assess the lower limit of required cooling power. In this study, an initial flow of 10 stp L/min was shown to reduce the temperature to approximately 0°C. The flow was then removed, and a 1 stp L/min pulse of _CO₂ was injected for approximately 10 seconds when the shaft temperature rose above 30°C. Although the temperature would have risen rapidly without cooling, only a small _CO₂ pulse was required to eliminate the temperature rise and maintain the system at ambient temperature (Figure 26). These results suggest that, for example, small amounts of _CO₂ can be used to maintain the antenna below ISO 60601-1 standards during the procedure. Temperature feedback/monitoring systems can be used to minimize _CO₂ usage during the procedure. Near-critical _CO₂ is an effective and viable alternative to liquid cooling within microwave ablation antennas. The increased heat capacity of NC- _CO₂ ensures that only a small volume of liquid is required to cool the ablation antenna to a safe level. The results indicate that a modest flow of approximately 10 stp L/min is sufficient to cool antennas generating up to 50 W of power.

Example VII.

This example evaluates the feasibility of using a novel reconstruction technique to improve visualization of the ablation zone while simultaneously reducing the contrast material dose by periodically injecting small doses of iodinated contrast material during the ablation procedure. The lack of a universally available and effective intraoperative imaging technique is a significant limitation in the field of thermal ablation for tumors. Ultrasound imaging can be obscured by bubbles formed during heating, and contrast-enhanced CT is typically limited to a single scan with a large contrast material dose.

Female domestic pigs were prepared and anesthetized. Radiofrequency ablation was performed for 20 minutes using three internally cooled switching electrodes. During the ablation procedure, 15 ml of iodinated contrast agent (300 mg/ml) was delivered every 2 minutes, and abdominal CT was acquired at a predetermined liver enhancement time (90 seconds) after each injection. CT images were created using conventional online reconstruction and offline reconstruction with highly constrained back projection (HYPR). Conventional images were compared with HYPR-reconstructed images for imaging contrast between the ablation zone and the background liver, as well as signal-to-noise ratio. CT images were created using conventional online reconstruction and offline reconstruction with highly constrained back projection (HYPR). Conventional and HYPR-reconstructed images were compared for imaging contrast between the ablation zone and the background liver, and signal-to-noise ratio.

The growth of the ablation zone can be visualized with a temporal resolution of 2 minutes. The ablation zone becomes apparent within 2–6 minutes, with an accumulated contrast dose of 15–45 ml. Image quality improves with the accumulated contrast dose. The SNR in HYPR-reconstructed images is approximately 3–4 times higher than that of standard reconstructions, and HYPR improves the signal contrast between the ablation zone and the background liver by up to 6 times (Figures 27 and 28).

All publications and patents mentioned in the above description are incorporated herein by reference. Various modifications and variations of the methods and systems described herein will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the present invention has been described in conjunction with specific embodiments, it should be understood that the claimed invention should not be unduly limited to these specific embodiments. In fact, various modifications of the described modes for implementing the present invention that are apparent to those skilled in the relevant art are intended to be within the scope of the appended claims.

Claims (7)

1. An ablation antenna device, comprising: a) an antenna comprising an inner conductor and a conductive fitting, wherein the antenna has a proximal end and a distal end, wherein the inner conductor has a distal end and a proximal end; and b) a conductive tip at the distal end of the antenna; wherein the inner conductor is not physically coupled to the conductive tip, the inner conductor is capacitively coupled to the conductive tip, wherein the inner conductor that is not physically coupled to the conductive tip is an innermost conductor of the antenna, the inner conductor being hollow, wherein the inner conductor includes a coolant channel for circulating coolant through the proximal end of the inner conductor and out of the distal end of the inner conductor, wherein the distal end of the inner conductor is adhered to and surrounded by the conductive fitting. 2 . The apparatus of claim 1 , wherein the antenna comprises a conductive outer conductor surrounding at least a portion of the inner conductor. 3. The device of claim 1, wherein the conductive tip comprises a trocar. 4. The apparatus of claim 1, wherein the conductive fitting extends distally beyond a distal-most end of the inner conductor. 5. The apparatus of claim 1, wherein the antenna further comprises an insulator, wherein the conductive tip is attached to the insulator, the insulator being attached to a distal end of the conductive fitting. The device of claim 5 , wherein the insulator comprises a ceramic insulator. 7. The apparatus of claim 5, wherein the conductive fitting, insulator, and conductive tip are positioned and sized to create a low impedance overlap to transfer energy to the conductive tip when energy is supplied to the inner conductor.