HK1056127A - Automated system for radiation treatment of a patient - Google Patents

Description

Automated system for radiation therapy of a patient

Technical Field

Generally, the present invention relates to a luminal radiation therapy system for delivering therapeutic compositions to a desired site within a lumen of a patient's tube via a catheter. More particularly, the present invention relates generally to an improved delivery device for treating and delivering therapeutic elements to a catheter.

Background

Balloon angioplasty has been widely used to open coronary artery occlusions since the late seventies of the twentieth century. Briefly, arterial dilation is accomplished by the procedure of pre-placing a balloon catheter at the site of arterial stenosis, inflating the balloon to enlarge the artery diameter, thereby opening the artery to allow greater blood flow therethrough, and Atherectomy (Atherectomy) to remove the obstruction or reduce the size of the obstruction, also used to achieve the same purpose.

Although balloon angioplasty has proven to be an effective method of opening coronary arteries. In most cases, however, the artery re-narrows at the site of balloon dilation, which is termed restenosis. Restenosis is believed to be due to the formation of scar tissue at the site of angioplasty, which is the result of injury to the artery upon balloon inflation, and more recently, intraluminal radiation has been used to treat the affected area of the artery following angioplasty or arteriotomy to inhibit cell proliferation and healing responses, and thus, to help inhibit restenosis. Such methods and apparatus for intraluminal radiation therapy are described in U.S. patent nos. 5,899,882 and 6,013,020 and in patent application No. 09/469,510 filed 1999, 12/22, all of which are incorporated herein by reference. These applications generally propose an apparatus consisting of a catheter with a lumen inserted into the patient's treated site and a delivery device for advancing or restoring a specific radiation treatment composition or "seed" along the catheter into and out of the treatment site by hydraulic or pneumatic pressure. A large number of therapeutic components make up a "source train".

As with any instrument inserted into the vascular system, it must be sufficiently intact to ensure that no debris or components become detached or dislodged from the instrument and enter the vascular system, which is particularly desirable for therapeutic compositions flowing into or out of the distal end of the catheter. Moreover, since the apparatus is intended for use with a radiation therapy composition, there is a high demand for safety to prevent any unintended patient or user exposure to radiation.

The practical use of the devices mentioned in the above patents and co-pending applications suggests that several points in the apparatus may be modified to reduce the likelihood of therapeutic components escaping the system, thereby improving patient and user safety.

It is therefore a primary object of the present invention to provide an integrated delivery device and catheter system with additional safety features to protect both the patient and the user from unintended radiation exposure.

More particularly, it is an object of the present invention to provide a delivery device/catheter integrated system in which the treatment composition cannot be inadvertently spilled from the delivery device. Moreover, it is also an object of the present invention to provide a delivery device that can advance and restore a "source train" of various lengths of therapeutic components for treating lesions of different dimensions. More particularly, the transfer device is adapted to accept replaceable cartridges for accommodating source queues of different lengths.

It is another object of the present invention to provide a delivery system that requires automatic and manual operation to facilitate safe passage of the treatment procedure to the user. More particularly, the delivery device automatically generates a pressurized fluid stream, detects the presence or absence of a therapeutic composition in the delivery device, and provides an electromechanical means of allowing or preventing the valve assembly from moving to an open or closed position, which prompts the user to sequentially and safely deliver therapy in accordance with appropriate operating procedures.

Disclosure of Invention

These objects, as well as others which will become apparent upon reference to the drawings and detailed description that follow, are achieved by a system comprising a microprocessor controlled delivery device and a separate catheter, at least one therapeutic element being delivered from a removable therapeutic element cartridge mounted in the delivery device to a separate catheter lumen via pressurized fluid controlled by a fluid control switch movable between a delivery and a retrieval position for treating a selected portion of the intraluminal tract of a patient. A safety interlock is provided to prevent (1) disassembly of the system unless the treatment element is fully resident within the treatment element cartridge, (2) actuation of the fluid control switch unless the system is armed. The safety interlock device includes a first lock switch that is movable from a first position to a second position only when the catheter and the treatment element cartridge are secured within the delivery device. The first locking switch prevents the fluid control switch from moving to the dispensing position when in the first position and prevents the catheter or treatment element cartridge from being removed from the delivery device when in the second position. When the liquid control switch is in the send position, it will lock the first locking switch firmly in the second position.

In a preferred embodiment, the safety interlock device comprises a two-arm spring, each arm being engageable by the catheter or the treatment element cartridge when the delivery device is contacted. A slide switch is provided that includes a yoke that is movable from a first position to a second position to capture the two arms of the spring and lock the catheter and the treatment element cartridge to the transfer device unless each arm is engaged by the catheter and the treatment substance cartridge. Each arm of the spring is capable of independently preventing the yoke from moving from the first position to the second position if not both arms are engaged.

The fluid control switch opens the valve means, which is movable between open and closed positions to respectively permit or prevent the flow of the treatment composition from the treatment composition cartridge when subjected to pressurized fluid. The solenoid locks the valve means open and only when the treatment composition resides in the cartridge does the solenoid disengage the valve means allowing the valve to close.

A photo interrupter or other sensor is connected to the first lockout switch or the fluid control switch to detect their position and generate a signal to the microprocessor to allow the treatment to continue based on the position of the first lockout switch and the fluid control switch.

A further aspect of the invention is to provide a system for detecting whether a therapeutic component resides at a target location along a lumen of a delivery device. The detection system includes a pressure sensor providing circuitry for comparing the measured differential pressure to a reference differential pressure corresponding to the differential pressure at the target site at which the therapeutic composition resides under the fluid pressure. The signal generator generates a signal when the measured differential pressure differs from the reference differential pressure by more than a predetermined value. This signal may activate an optical signal and/or a mechanical interlock that prevents the catheter from separating from the delivery device and prevents the valve from closing when the signal generator activates the signal due to a pressure differential created when the therapeutic component does not reside at the target location.

In an alternative embodiment of this aspect of the invention, the pressure sensor is fluidly coupled to the lumen of the delivery device, enabling it to accurately measure the pressure of the fluid at a single point along the lumen of the delivery device and distal to the target site where the therapeutic elements are stored along the lumen of the delivery device. The measured pressure at this single point is compared to a predetermined pressure or a reference pressure corresponding to the pressure at the same point when the therapeutic composition resides at the target site under the pressure of the fluid. The signal generator generates a signal when the measured pressure differs from a predetermined or reference pressure by more than a predetermined value.

Drawings

FIG. 1 is a perspective view of a treatment system according to the present invention including a delivery device and a catheter.

Fig. 2 is a bottom perspective view of the system of fig. 1.

Fig. 3 is a perspective view similar to fig. 2, except with the hatch removed to show the battery pack storage compartment.

Fig. 4 is an exploded perspective view of the transfer device shown in fig. 1.

Fig. 5 is a perspective view of the transfer device of fig. 1 with the upper portion removed and shown in detail.

Fig. 6 is an enlarged plan view of the first lock switch, catheter and treatment element cartridge shown in partial cross-section detail.

Fig. 7 is a fragmentary perspective view of the transfer device showing the relationship of the valve assembly and the treatment element cartridge.

Fig. 8 is a cross-sectional view taken generally along line 8-8 of fig. 7.

Fig. 9A and B are schematic views of the liquid flow path in the transfer device.

Figures 10A-M are flow diagrams illustrating logic used by the microprocessor to perform interactive treatment using the intraluminal ductal treatment system based on commands entered by the user.

Fig. 11 is a schematic diagram of the system electronics of the transfer device of fig. 1.

Fig. 12A-L are system electronic circuit diagrams of the transmission device shown in fig. 1.

Detailed Description

The present invention relates to an automated catheter-based radioactivity delivery system, generally designated 10, and a method for treating a desired site in a patient. The system includes a supply catheter 12, a plurality of treatment composition/marker seeds 14 (best seen in FIG. 6) forming a "source train", and a delivery device 16 that electromechanically supplies the source train of treatment composition to a selected site in the patient's body through the catheter 12. The transmission means 16 is controlled by a microprocessor which is programmed to guide the user through the correct operation with a series of separate prompts which, together with the operation input controls, provide an intuitive user interface.

The assembled transfer device can be seen in fig. 1 and 2. The shape of the delivery device 16 is ergonomically designed to be easily held in one or both hands and to be equally comfortable for left or right handed clinicians. As can be seen from fig. 1 and 2, a streamlined handle 18 is provided on both the left and right sides of the transfer device 16. The device may be placed in the palm or on a flat surface of a user. When holding the device with both hands, the control can be easily performed with the thumbs.

The upper and lower housings 20, 22 cooperate to form a housing for supporting the internal components of the device. The led display screen 26 is viewable by a user through an opening 24 in the upper housing 20. The fluid control switch 28 extends through a second opening 30 in the upper housing 20, while a safety lockout switch 32 extends through complementary openings 34, 36 in the left hand grip of the upper and lower housings 20, 22. The membrane keypad also effectively seals the control system from moisture by operating the electronic control system through the membrane keypad. Selection keys, buttons, or components may be used to operate the electronic control system of transfer device 16.

The upper housing portion 20 also includes a window 38 (fig. 8) for viewing the sleeve 40 and pin valve 42. The cartridge contains a source train of treatment composition (consisting of a plurality of treatment compositions and a marker seed). The sleeve is preferably made of a radiation resistant material such as quartz, synthetic fused silica, polycarbonate, or the like.

The lower housing portion 22 has a central opening 44 for receiving the power supply of the device, most likely a replaceable or rechargeable battery pack 46 (fig. 4). The battery pack 46 may have a unitary plastic housing with external contacts (not shown) that electrically connect with similar contacts at the central opening 44. Thus, the battery pack 46 is enclosed and made quickly accessible to the user from the exterior of the transfer device 10, ensuring easy replacement or recharging. Optionally, a hard cover may be used to securely cover the outside of the battery pack 46, completely enclosing the battery portion 44.

The upper housing portion 20 and the lower housing portion 22 together also define an opening for insertion of a liquid cartridge assembly 48. The fluid cartridge 48 contains saline, sterilized, purified or distilled water, or some other source of fluid for supplying the source train by hydraulic or pneumatic means. The fluid cartridge assembly 48 includes a cylindrical fluid reservoir 50, a three-way valve 52 for directing fluid into and out of the fluid reservoir 50, and may also include a handle 54 for facilitating the attachment and detachment of the fluid reservoir 50 of the transfer device 16. The transfer set 16 has a fluid manifold 56 (shown schematically in fig. 9) including a fluid collector in the form of an elongated appendage 56, which has two ports, a fluid inlet port 55 and a fluid outlet port 57, through which fluid is respectively fed into and out of the fluid conduit of the transfer set 16. The three-way valve 52 has a small opening for receiving the extension attachment 56 when the fluid cartridge 48 is inserted into the transfer device 16, and provides a fluid tight seal around the extension attachment. For a safer connection, the transfer device 16 and the fluid cartridge 48 may be threaded to mate threads to screw the fluid cartridge 48 into the transfer device 16.

The fluid cartridge assembly may be disposable or removable for ease of cleaning and replacement of used fluid with fresh fluid. After each treatment, the used disposable fluid cartridge 48 may be discarded or replaced with a pre-filled fluid cartridge.

Fig. 9 is a schematic flow diagram of the liquid, beginning with the liquid reservoir 50 and extending through the supply system. Through an output port 57 of the manifold 58, the fluid cartridge 48 is fluidly connected to a pressure pump 60, which draws fluid in and forces it through fluid conduits, effectively delivering, retaining and recovering the therapeutic elements. The pressure pump 60 can be programmed to operate in a single direction for delivery and recovery of the treatment composition, or to alternate between delivery and recovery modes.

When the pump is pumping fluid in one direction, the system relies on a fluid control valve 62, preferably one that can be manually operated by the user of the delivery device, to properly direct the flow of fluid. The fluid control valve 62 communicates with all of the fluid conduits in the transfer device 16, the source cartridge 64 (described in detail below), and the additional supply conduit 12. In the delivery mode, the fluid control valve 62 directs fluid through the source cartridge 64, through the source delivery lumen into the catheter, and out of the catheter via the fluid recovery conduit. In the recovery mode, the fluid control valve 62 reverses the direction of fluid flow.

In use, the force required to deliver and withdraw the treatment element into and out of the catheter is greater than the force required to maintain the treatment element at the desired location in the catheter for treatment. Thus, to conserve energy, the pump 60 is run at a reduced rate while maintaining the position of the treatment elements. When treatment is complete, the pump 60 is run at full speed again to force the treatment element back into the source cartridge 64 in the transfer device 16. When no treatment elements are being delivered, maintained or recovered, the pump 60 is stopped.

In the event that the pump is inoperable when the treatment composition is not loaded into the source cartridge 64, the user may manually force the automatic fluid management system to retrieve the treatment composition. For example, a user may easily access a syringe connector 66 (see FIG. 3) through the battery compartment that is connected by fluid and fluid flow paths, and a fluid-filled syringe (not shown) may be attached to the connector as a pressurized fluid source to force all of the therapeutic composition back into the source cartridge 64.

The source cartridge 64 contains an interchangeable assembly (best seen in fig. 4 and 5). To enable the transfer of source trains of various lengths, the source cartridge assembly 64 houses a quartz sleeve 40 having an interior chamber 70 in which the treatment elements/member seeds 14 comprising the source train are stored. The pin valve 42 is also integrated with the quartz sleeve 40. Interchangeable cartridges 64 containing source trains of different lengths allow the user to select the cartridge containing the source train of the appropriate length required to treat the patient. Each cartridge 64 may store a source train of the maximum length required to be used for treatment of coronary or external vessels. The source train shorter than the maximum length is accompanied by a positioner (not shown) that brings the source train 43 directly adjacent the pin valve 42 in the distal end of the quartz sleeve lumen 70. After the source cartridge 64 is inserted into the transfer device 16, the fluid control valve 62 is fluidly connected to the tubing in the transfer device 16 and the supply conduit 12 to form a complete fluid path.

Referring to fig. 5, the upper middle portion of the source cartridge has an elongated opening 72 for allowing a user to view the transparent quartz sleeve 40. A transparent window piece is mounted over the opening 72 for visual observation of the treatment composition/marker seeds 14 and pin valve 42 contained within the quartz sleeve 40, and a magnifying glass replaces the entire window and magnifies the treatment composition and marker seeds. The end of the window or magnifier may be combined with a circular magnifier to further magnify at least the pin valve 44 and the distal marker seed area of the source train. A magnifying lens may also be added to the window 38 of the transfer device 16.

To further enhance the visual inspection of the treatment composition 14, back illumination may be added, for example, by mounting an illuminating light emitting diode or an illuminating panel attached to a fiber optic plate underneath the quartz sleeve 40 inside the source cartridge 64.

Referring to fig. 8, the pin valve 42 is located in a conduit that is perpendicular to the intermediate chamber 70 and connects the intermediate chamber 70 to the exterior of the quartz sleeve 40, similar to that shown in fig. 39A and 39B of U.S. patent application No. 08/936,058, incorporated by reference above. The pin valve 42 operates between a closed position, in which it severs the quartz lumen 70, preventing the source train from flowing out of the quartz sleeve 40, and an open position, in which it is retracted to allow the source train to be transported to the catheter 12. Inside the opening of the source cartridge 64 and outside the quartz sleeve 40, the other parts of the pin valve assembly 42 are placed: the pin 74, seal 76, rod 78 and compression spring 80, the pin valve 42 is controlled by a slide member 82 having an elongated cam portion 84 (see fig. 8) that engages the rod 78 to move and maintain the pin valve 42 in the open position. When the slide member 82 is opened, the cam portion 84 is no longer engaged with the lever 78 and the pin valve is closed.

The source cartridge assembly 64 also includes a large knob 86 that allows it to be easily loaded into and unloaded from the transfer device 16. The handle 86 may include a source train length indicator and/or color coding to distinguish other cartridges 64 containing source trains of different lengths.

The source cartridge 64 may also include non-volatile memory for storing source train specific information (such as its length, radioactivity, and number of times used for radiation therapy, etc.) in a collection of alphanumeric characters in a 16-ary format. The transmitting device 16 may also check the data to ensure that it meets the specified range. If the data is outside the specified range, the transmission device 16 will indicate that the error does not allow the start of treatment.

Before disconnecting the catheter 12 or source cartridge 64 from the transfer device 16, the user must ensure that all of the treatment composition is contained within the quartz sleeve 40 and behind the closed pin valve 42. This can be accomplished by visually inspecting the source train through a viewing window in the quartz sleeve 40 inside the source cartridge 64. Visual inspection may be enhanced by increasing the illumination provided by the light emitting diode to which the optical fiber is attached.

However, in one aspect of the invention, a seed detection system is provided to determine whether the source train is located between the proximal and distal ends in the lumen of the quartz sleeve based on the liquid pressure drop of the lumen 70 in the quartz sleeve 40. Referring to fig. 6 and 9A, the seed detection system includes a pressure sensor 88 in fluid communication with the lumen 70 in the quartz sleeve 40 via access ports 90, 92 at the proximal and distal ends of the path through the source cartridge 64, respectively. The access port 90 is connected to the source cartridge 64 when the source cartridge 64 is inserted into the transfer device 16. The access port 92 is secured to a safety interlock device 94, described below, and completes the fluid path when the safety interlock device 94 is placed into connection with the source cartridge 64 and the catheter 12.

The sensor 88 generates a first or reference signal based on the pressure drop across the quartz sleeve lumen when all of the active queued therapeutic ingredient/marker seeds are loaded into the quartz sleeve lumen 70. The pressure sensor continuously senses the pressure drop across the ports 90, 92 and it will be readily appreciated that if the seed/marker 14 of the source train resides outside the quartz sleeve 40, such as within the conduit 12, the pressure drop across both ports 90, 92 should be negligible. A microprocessor for controlling the transmission device compares the measured differential pressure with a reference differential pressure and generates a signal when the measured differential pressure differs from the reference differential pressure by more than a predetermined value, such as 10%. The signal activates an optical signal on the display and/or mechanical interlock of the transfer device that prevents the catheter 12 and source cartridge 64 from being separated from the transfer device 16 based on the signal received from the signal generator.

In practice, the sensor 88 is self-calibrating, so it is adapted to measure a reference pressure drop within the quartz lumen 70 that houses the source train of different lengths for the transport apparatus. In practice, a honeywell "wet-wet" sensor is expected to be used for measurements of different pressures.

In an alternative embodiment of this aspect of the invention, as shown in FIG. 9B, the seed detection system includes a pressure sensor 88 connected to the lumen 70 of the quartz sleeve 40 through a single port 92 distal to the path of fluid flow through the source cartridge 64. The measured pressure is compared to a predetermined pressure or reference pressure corresponding to the pressure at the port 92 when the treatment composition 14 is hydraulically resident at the target site. The signal generator generates a signal when the measured pressure differs from the predetermined pressure or the reference pressure by more than a predetermined amount. In practice, the Microswitch 27PC series sensor is expected to be used for any embodiment of pressure measurement.

To ensure that there is a sufficient difference in pressure drop across the lumen of the quartz sleeve or at individual locations along the lumen of the delivery device when the treatment composition/marker seed is not within the lumen of the quartz sleeve, the treatment composition/marker seeds 14 may be combined so that they are fed into or out of the quartz sleeve as a unit. This helps prevent reading errors, such as might occur if most, but not all, of the individual treatment elements/marker seeds 14 were returned to the lumen of the quartz sleeve 40 after the treatment procedure is completed.

In addition to the differential pressure detection system for determining the presence of the source train, other sensors may be included in the transfer device 16 to detect the presence of the fluid cartridge 48, the source cartridge 64, and the catheter 12. Such sensors may be of any of a variety of well-known types, such as mechanical, electromechanical (e.g., a leaf spring with a microprocessor for measuring its movement and detecting its position), electronic (e.g., a travel switch or limit switch), magnetic (e.g., a reed switch with a permanent magnet), electromagnetic (e.g., a hall effect sensor), or optical sensors. Other types of sensors include displacement and position sensors, proximity sensors, occupancy motion (occupancy) sensors, pressure sensors, and force or strain sensors.

In the illustrated embodiment, for each of the three connections, an optical sensor may be combined with the illumination light source, such as an infrared LED. The illumination source is positioned such that, when properly connected to the transfer device 16, the fluid cartridge 48, the source cartridge 64, and the catheter 12 each cut off the beam of illumination source light. The sensor detects the change in the amount of projected light and communicates it to the electronic control system of the system. If one or more of the fluid cartridge 48, the source cartridge 64, and the transfer conduit 12 is not properly connected to the transfer device 16, a graphical user interface will indicate the lack of connection and will prevent the user from continuing to operate until corrected.

According to another feature of the present invention, a safety interlock is provided to prevent (1) removal of the catheter and source cartridge from the delivery device unless all of the treatment/marker components 14 are stored in the source cartridge 64 and (2) opening of the fluid control valve to the "send" position unless the system is assembled.

Referring to FIG. 4, a safety interlock device 94 including the slide switch 32 is provided that mates with the proximal-most connectors 98 of the source cartridge 64 and the supply catheter 12 connected to the transfer device 16 when the transfer device 16 is connected to the source cartridge and supply catheter. If the safety interlock device is not tightly coupled to the connector 98 on the transfer catheter 12 and the source cartridge 64, it is placed in a position to block movement of the fluid control switch 28, which controls the fluid regulator valve 62 so that it cannot move to the "send" position. Conversely, when the safety interlock device 98 is engaged with the connector 98 on the supply conduit 12 and the source cartridge 64, the fluid control switch 28 blocks the slide switch 32 from moving to a position where the conduit connector 98 and the source cartridge 64 are separated.

As best seen in FIG. 6, the safety interlock device 94 includes a spring 102 with two arms 104, 106 and a central opening 108 that receives a protruding portion 110 of the catheter connector 98. When the catheter connector 98 and source cartridge 64 are properly mounted to the transfer device 16, the arms 104, 106 of the spring 102 are connected and compressed, respectively, and the spring pressure is overcome to move the arms 104, 106 toward each other, respectively. This allows the spring arms to be inserted into an internal slot 112 on the switch 32 so that the switch 32 can be slid into locking engagement with the receptacle portions 114 and 116 on the catheter connector 98 and the source cartridge 64, respectively. In particular, the switch includes a yoke member 118 that captures the hub on the catheter connector and source cartridge when the spring is compressed when the catheter and source cartridge are in the correct position. The receptacles 114, 116 are inserted into the shoulders 120 of the mouth of the socket 112. If the catheter connector 98 or source cartridge 64 is not properly positioned, the spring arms 104 or 106 are not compressed, and the spring arms 104 or 106 will engage the shoulder 118 at the mouth of the receptacle 112, preventing the switch 32 from sliding into the latched position, thus preventing the liquid control switch 32 from moving to the "send" position. Referring to fig. 7, the fluid control switch 28 also has an arm 122, and when the switch 32 is in the locked position and the fluid control switch 28 is in the "send" position, the arm 122 engages a shoulder 123 (fig. 6) on the switch 32 to prevent the catheter 12 and source cartridge 64 from being separated from the transfer device 16 when in this mode.

To provide further assurance against inadvertent or improper operation of the treatment system, the fluid control switch 28 may incorporate a solenoid 124 that locks the pin valve arrangement 74-82 in the open position, allowing it to close only when the treatment composition/marker seed resides within the treatment composition cartridge. The solenoid 124 may be operated, such as by the treatment composition detection system described previously.

In the event that the pump 60 fails to operate or fails electronically, and the treatment composition 14 is not contained within the source cartridge 64, the user may manually force the automatic fluid management system to recover the composition 14. The feature of forcing the solenoid 124 is also required to ensure manual recovery of the treatment composition 14 within the source cartridge 64 by closing the pin valve 42. An opening 126 (fig. 2) in the transfer device 16 is the passage for the manually operated solenoid 124. When the pin is inserted into the opening 126, it displaces a beveled edge element, which causes the solenoid plunger to retract from the slide assembly 82, allowing the pin valve to close.

In addition, a sensor, preferably a photo interrupter, may be associated with the switch 32, the photo interrupter being triggered when the switch 32 is moved to the locked position. The triggered photointerrupter generates a signal that is sent to the microprocessor to continue the treatment. A similar photo interrupter may be incorporated with the fluid control switch to detect the switch position and generate a signal to the microprocessor to allow the treatment to continue depending on the position of the fluid switch. Although a photointerrupter is the preferred sensor, a wide variety of other types of sensors, such as those described above, may be used in place of the photointerrupter.

The transfer device 16 may be connected to any of the conduits already mentioned in the prior patents and applications incorporated by reference in this specification. The catheter may be made of any one or a combination of nylon, PEBAX, polyimide, polyethylene, and polyurethane.

The therapeutic component/marker seed of the source train may also be any of the components mentioned in the patents and applications incorporated herein by reference. A source train consists of a series of treatment components and two marker seeds, one at each end of the source train. Preferably, the treatment composition is a radioactive cylinder. The marker seeds are used to properly place the treatment elements at the treatment site, and are preferably platinum, platinum-iridium, gold, or gold plated, as each is readily apparent under fluorescence (fluorescence is used to monitor radiation therapy).

Referring to fig. 10A-M, a flow chart illustrating the logic of a microprocessor installed to a transmission device to control its operation can be seen. The flow chart guides the operator through a series of steps, starting with fig. 10A with the transmission on, and ending with the program, fig. 10M with the transmission off, and shows the information displayed by the light emitting LED 26.

Schematic electronic diagrams and schematic electronic circuit diagrams are shown in fig. 11 and 12A-L, respectively. The electronic circuitry is printed on a circuit board which is sealed within a tray 128 by the membrane keypad 37. The electronic circuitry includes microprocessor 130, control pressure sensor 88, solenoid 124, pump 60, battery pack 46, sensors, audio or visual alarms, display interface, thin interface, and illumination of the back of the source train.

Accordingly, the present invention discloses a luminal radiation therapy system that satisfies all of the objectives of the present invention. While the system has been described in terms of preferred embodiments, it is not intended that the invention be limited to the preferred embodiments. But rather the invention is defined in the claims.

Claims (12)

1. In a system comprising a microprocessor controlled delivery device and a separate catheter, pressurized fluid controlled by a fluid control switch movable between a delivery and a retrieval position, and infusion of at least one therapeutic element from a removable therapeutic element cartridge mounted in the delivery device into a lumen of the catheter, for endoluminal treatment of a selected portion of a patient's body, a safety interlock device for preventing system detachment (unless the therapeutic element is resident in the therapeutic element cartridge) and actuation of the fluid control switch (unless the system is installed), the safety interlock device comprising:

a first lock switch movable from a first position to a second position only when the catheter and the treatment element cartridge are secured to the transfer device, the first lock switch preventing the fluid control switch from moving to the delivery position in the first position, the first lock switch preventing the catheter or the treatment element cartridge from being separated from the transfer device in the second position, the first lock switch further locking the first lock switch in the second position when the fluid control switch is in the delivery position.

2. The safety interlock device according to claim 1, wherein the first locking switch comprises:

a spring having two arms, each spring arm engaging one of the catheter or the treatment element cartridge when mounted to the delivery device; and

a slide switch including a yoke that moves from a first position to a second position only when each spring arm engages one of the catheter and the treatment element cartridge, thereby capturing the spring arm and locking the catheter and treatment element cartridge to the transfer device, each spring arm independently preventing the yoke from moving from the first position to the second position if not engaged with one of the catheter and the treatment element cartridge.

3. The safety interlock device of claim 2 wherein the slide switch has a shoulder and the fluid control switch includes an arm that engages the shoulder when the yoke is in the second position and the fluid control switch is in the send position.

4. The safety interlock device according to claim 1 further comprising:

a valve means movable by the fluid control switch between an open position and a closed position to permit or prevent, respectively, removal of the treatment composition from the treatment composition cartridge under the influence of the pressurized fluid;

a solenoid locks the valve means in the open position, and the solenoid is not engaged with the valve means to allow it to close only when the treatment composition is resident in the treatment composition cartridge.

5. The safety interlock device according to claim 1 further comprising:

a photointerrupter triggered when the first locking switch is moved to the second position to lock the treatment element cartridge and catheter to the transfer device, the triggered photointerrupter generating a signal that is communicated to the microprocessor to allow the treatment to continue.

6. The safety interlock device according to claim 4 further comprising a series of photo-interrupters in communication with the fluid control switch for detecting the position of the fluid control switch and generating a signal to the microprocessor based on the position of the fluid control switch to allow the treatment to continue.

7. In a delivery device for intraluminal treatment of a selected site on a body by a catheter adapted for placement within a body lumen, the delivery device being external to the body and having a lumen for storing at least one therapeutic element, the therapeutic element being transferred from the delivery device to the catheter by a pressurized fluid, a system for detecting whether the therapeutic element resides at a target location along the lumen of the delivery device comprising:

the pressure sensor connected with the inner cavity of the transmission device through liquid can measure the liquid pressure difference across the target position of the inner cavity;

circuitry for comparing the measured differential pressure to a reference differential pressure, the reference differential pressure corresponding to a differential pressure at the target location when the therapeutic composition resides at the target location under the fluid pressure;

a signal generator provides a signal when the measured differential pressure differs from the reference differential pressure by more than a predetermined percentage.

8. The transmission apparatus of claim 7 further comprising an optical signal excited by the signal generator.

9. The delivery device of claim 7 further comprising a mechanical interlock between the delivery device and the catheter for preventing the catheter from separating from the delivery device when activated by a signal from the signal generator.

10. In a delivery device for intraluminal treatment of a selected portion of a body by a catheter adapted for placement within a body lumen, the delivery device being external to the body and having a lumen for storing at least one therapeutic component, the therapeutic component being transferred from the delivery device to the catheter in the form of a pressurized liquid, a system for detecting whether the therapeutic component resides at a target location along the lumen of the delivery device comprising:

the liquid pressure at the target position of the inner cavity can be measured by a pressure sensor connected with the inner cavity of the transmission device through liquid;

circuitry for comparing the measured pressure to a reference pressure, the reference pressure corresponding to a pressure at the target location of the therapeutic composition at the target location at the fluid pressure;

a signal generator provides a signal when the measured pressure differs from the reference pressure by more than a predetermined percentage.

11. The transmission apparatus of claim 10 further comprising an optical signal excited by the signal generator.

12. The delivery device of claim 10 further comprising a mechanical interlock between the delivery device and the catheter for preventing the catheter from separating from the delivery device when activated by a signal from the signal generator.