CN109938840B - Liquid metal in vitro marker device and tracking method for in vivo structure tracking - Google Patents

Abstract

The invention discloses a liquid metal in-vitro marker device for in-vivo structure tracking and a tracking method. The invention adopts the liquid metal layer prepared by the liquid metal as the visual mark and the medical imaging mark at the same time, and solves the problems that the spatial positions are not unified and extra calibration is needed in the two imaging processes in the prior art; the invention can obtain the flexible thin layer as an identifiable mark to be directly attached to the surface of the imaging object, thereby ensuring the tracking stability of the internal structure and reducing the interference of the marker on the imaging; meanwhile, a traceable marker array can be formed by adopting a plurality of light and thin identifiable markers simultaneously, so that the internal structure to be traced can be better covered; the invention can manufacture a large amount of recognizable marks with large coverage area by a printing or coating method, thereby reducing the cost and improving the accuracy of tracking the in-vivo structure.

Description

Liquid metal in vitro marker device and tracking method for in vivo structure tracking

technical field

The invention relates to the technical field of computer aided medical treatment, in particular to a liquid metal in vitro marker device and a tracking method for in vivo structure tracking.

Background technique

In vivo structure tracking refers to the measurement and tracking of the spatial position and posture of a specific tissue structure inside an organism by a certain technical method (usually using medical imaging methods). In the field of medical technology, internal structure tracking is required in surgical guidance equipment such as electrode placement, puncture, nail placement, ablation, and radiotherapy. Such equipment is widely used in clinical departments such as neurosurgery, orthopedics, interventional departments, and radiotherapy departments. .

In vivo structure tracking method based on body surface markers, first place body surface markers for tracking on the body surface near the structure to be tracked, and use medical imaging equipment such as CT, X-ray or magnetic resonance to establish the relationship between the body surface markers and the structure to be tracked. The relative spatial positional relationship between the tracked target anatomical structures in the body. During the operation, the position of the structure to be tracked will move with the position of the patient. The body surface markers are tracked by the optical tracking system. The spatial position of the surface marker and the pre-established relative spatial positional relationship between the body surface marker and the structure to be tracked in the body realize the tracking of the body structure of the patient. Compared with the in vivo marker tracking method used in clinical practice (for example, patent CN 105251126A), this method has the advantages of less trauma, less radiation dose, simplicity and practicability.

However, as the core device of this method, the currently used in vitro markers are still insufficient. The first is that visual marks and medical imaging marks are not unified. Common optical tracking systems can only identify visual marks made of specific shapes, colors, and textures (such as luminous balls, two-dimensional codes, etc.), and conventional imaging methods are difficult to detect such visual marks. Marking for imaging requires the introduction of additional medical imaging markers (such as steel balls, metal grids, etc.), and due to problems such as space obstruction, it is difficult to completely coincide the positions of the two markers, so an additional calibration process is often required to establish the relationship between the two markers. This not only increases the complexity of the tracking process, but also introduces unnecessary calibration errors, such as the patent CN107468351. Another aspect is the ease of use of the marker. To ensure accuracy, the marker device needs to be directly connected to the patient's body. Since visual markers and medical imaging markers need to maintain a certain relative positional relationship, in vitro markers are mostly designed as large rigid structures, which are not only inconvenient to fix with the patient, but also difficult to ensure a good fit between the markers and the skin surface, and it is easy to introduce more many errors. At the same time, the large rigid markers also make it difficult to simultaneously image the structures to be tracked and the markers in vitro.

SUMMARY OF THE INVENTION

In view of the above problems in the prior art, the present invention proposes a liquid metal in vitro marker device and a tracking method for in vivo structure tracking, which solves the inconsistency between in vitro marker visual markers and medical imaging markers in the existing in vivo structure tracking methods. Uniform, inconvenient to use and other issues.

Liquid metal is a liquid metal alloy material at room temperature. It has good printing and coating properties, and can be made into any shape, soft and thin markers. At the same time, liquid metal has good developing ability in medical imaging devices. The invention solves the technical problem that medical imaging marks are different from visual imaging marks by means of this physical property of liquid metal.

The medical imaging device of the present invention refers to an imaging device based on the principle of radiation attenuation imaging, such as an electronic computed tomography CT device, a cone beam electronic computed tomography CBCT device or an X-ray machine, etc.; the X-ray used for imaging in the medical imaging device And gamma rays are collectively referred to as medical imaging rays.

One object of the present invention is to propose a liquid metal in vitro marker device for in vivo structure tracking.

The liquid metal in vitro marker device for in vivo structure tracking of the present invention includes: a liquid metal layer, a marker base layer, an encapsulation layer and a connection layer; wherein, the liquid metal layer adopts liquid metal to form a structure with a specific shape or texture as a Recognizable marks, liquid metal has the ability to develop under medical imaging equipment, medical imaging devices can identify liquid metal, so as to identify identifiable marks through image processing algorithms, and optical imaging devices can identify identifiable marks through visible light imaging and image processing, Therefore, medical imaging equipment and optical imaging equipment can identify the liquid metal layer at the same time; medical imaging equipment and optical imaging equipment can identify the liquid metal layer at the same time, which means that medical imaging equipment can simultaneously observe and identify through medical imaging rays and optical imaging equipment through visible light. At least one identifiable marker position of the markers, the identifiable marker position of the medical imaging device and the identifiable marker position of the optical imaging device are located in the same spatial position, or the identifiable marker position of the medical imaging device and the identifiable marker position of the optical imaging device are located at the same spatial position The positions are located in different spatial positions, but there is a specific geometric position relationship between them; the liquid metal layer is arranged on the upper surface of the marker base layer to form a composite body; the composite body is encapsulated in the encapsulation layer and the connection layer; the connection layer is located in the marker The lower surface of the object base layer; the liquid metal in vitro marker device is located on the surface of the imaging object, and is connected to the surface of the imaging object through the connecting layer; the liquid metal in vitro marker device and the internal structure of the imaging object to be tracked are located on the imaging device of the medical imaging device. In the field of view, the medical image of the liquid metal layer and the internal structure to be tracked is obtained through the medical imaging device; the image processing algorithm is performed on the medical image to obtain the spatial position relationship between the liquid metal layer and the internal structure to be tracked; the optical imaging device passes through The encapsulation layer performs image recognition and measurement on the identifiable marks of the liquid metal layer, and obtains the spatial position and attitude in the coordinate system of the optical imaging device; through the spatial position relationship between the liquid metal layer and the internal structure to be tracked and the liquid metal layer in the optical imaging The spatial position and attitude under the device coordinate system realizes the tracking of the spatial position and attitude of the internal structure to be tracked.

The specific shape or texture structure of the liquid metal layer adopts a combination of one or more of the grid-shaped array, the dot array and the spherical array, or adopts a combination of dots, line segments, arcs, polygons, sectors, circles A single specific shape or array of shapes consisting of one or more of a shape and a torus. The plane size of a single shape is between 0.5-100mm, the shape accuracy is better than 0.5mm, the thickness is controlled between 0.1-1mm, the diameter of the dot is 1-10mm, the line width of the line is 0.5-5mm, polygonal, fan-shaped, The plane size of the circle and the ring is 2 to 100mm. Liquid metal is a low melting point metal element or metal alloy with a melting point below 80 °C, using gallium, indium, gallium indium alloy, gallium indium tin alloy, gallium indium zinc alloy, gallium indium tin zinc alloy, bismuth indium alloy, bismuth tin alloy, One or more of bismuth-indium-tin alloy, bismuth-indium-zinc alloy and bismuth-indium-tin-zinc alloy, or a combination of the above-mentioned various metal elements or metal alloys and nano- or micro-particles with medical imaging ray absorption and color rendering respectively. mixture.

The marker base layer serves as a structural layer supporting the liquid metal layer, and at the same time provides an imaging contrast background for the identification of optical imaging devices and medical imaging devices. The liquid metal structure layer is formed on the upper surface of the marker base layer by a method of printing, coating, pouring, filling or inlaying. The base layer of the marker is a material with a low attenuation coefficient for medical imaging rays, using one of polymer materials, paper, cloth, aluminum and aluminum alloys, and the polymer materials are polyethylene PE, polyvinyl chloride PVC and polypropylene. A kind of PP. The marker base layer and the liquid metal have a color difference that can be resolved by an optical imaging system.

The encapsulation of the composite is adopted in the encapsulation layer and the connection layer: the encapsulation layer wraps all surfaces of the composite inside, and the connection layer is arranged on the lower surface of the marker base layer outside the encapsulation layer; or, under the marker base layer of the composite body. A connection layer is arranged on the surface, and an encapsulation layer is covered on the upper surface of the liquid metal layer. The connection layer and the encapsulation layer together form an interior sealed space, and the composite body is encapsulated in the interior sealed space. The encapsulation layer is made of materials that can transmit visible light. The optical imaging device can observe the identifiable mark of the liquid metal layer through one or both sides of the encapsulation layer; the medical imaging device can observe the identifiable mark of the liquid metal layer through the encapsulation layer. . The material of the encapsulation layer is a material that can transmit both visible light and medical imaging sources, and a transparent polymer material, which is one of silica gel, latex, polyethylene PE, polyvinyl chloride PVC, polypropylene PP and polymer paint. or more.

The connection layer adopts the connection method of glue bonding, clamping, screw connection or electromagnetic connection to connect the liquid metal layer, the base layer of the marker and the encapsulation layer with the surface of the imaged object.

The liquid metal layer, marker base layer, encapsulation layer and connection layer can be made of flexible materials according to requirements, and rigid materials can also be used if necessary.

Further, the present invention adopts a plurality of liquid metal layers to form a traceable marker array, so as to achieve better coverage of the internal structure to be tracked.

Another object of the present invention is to provide a tracking method of a liquid metal in vitro marker device for in vivo structure tracking.

The tracking method of the liquid metal in vitro marker device for in vivo structure tracking of the present invention comprises the following steps:

1) The liquid metal in vitro marker device is placed on the surface of the imaging object near the internal structure to be tracked, and is connected to the surface of the imaging object through the connecting layer;

2) The liquid metal in vitro marker device and the internal structure to be tracked of the imaging object are all located within the imaging field of view of the medical imaging device, and the medical imaging device obtains a medical image of the liquid metal layer and the internal structure to be tracked;

3) Perform an image processing algorithm on the medical image to obtain the spatial positional relationship between the liquid metal layer and the internal structure to be tracked;

4) The optical imaging device performs image recognition and measurement on the identifiable mark of the liquid metal layer through the encapsulation layer, and obtains the spatial position and attitude in the coordinate system of the optical imaging device;

5) Through the spatial position relationship between the liquid metal layer and the internal structure to be tracked and the spatial position and attitude of the liquid metal layer in the coordinate system of the optical imaging device, the tracking of the spatial position and attitude of the internal structure to be tracked is realized.

In step 3), the spatial positional relationship includes the positional offset and attitude rotation between the internal structure to be tracked and the liquid metal layer.

Advantages of the present invention:

The present invention adopts the liquid metal layer prepared by liquid metal as both a visual mark and a medical imaging mark, which solves the problem that the spatial positions of the two types of imaging processes in the prior art are not uniform, and additional calibration is required; the present invention can obtain a flexible thin layer as a The identifiable marker is directly attached to the surface of the imaged object to ensure the stability of the internal structure tracking and reduce the interference of the marker to the imaging; at the same time, multiple thin and light identifiable markers can be used to form a trackable marker array to realize the tracking. The internal structure of the device can be better covered; the invention manufactures a large number of identifiable marks with a large coverage area by printing or coating, which can reduce the cost and improve the accuracy of tracking the internal structure.

Description of drawings

1 is a cross-sectional view of an embodiment of a liquid metal in vitro marker device for in vivo structure tracking of the present invention;

2 is a top view of the liquid metal layer of an embodiment of the liquid metal in vitro marker device for in vivo structure tracking of the present invention, wherein (a), (b) and (c) are three types of liquid metal layers, respectively The top view of the specific implementation;

FIG. 3 is a schematic diagram of the liquid metal in vitro marker device for in vivo structure tracking of the present invention used for tracking.

Detailed ways

Below in conjunction with the accompanying drawings, the present invention will be further described through specific embodiments.

As shown in FIG. 1 , the liquid metal in vitro marker device for in vivo structure tracking in this embodiment includes: a liquid metal layer 1 , a marker base layer 2 , an encapsulation layer 3 and a connection layer 4 ; wherein, the liquid metal layer 1 is made of liquid metal. Metal, constitutes a structure with a specific shape or texture as an identifiable mark; the liquid metal layer 1 is arranged on the upper surface of the marker base layer 2 to form a composite body; the composite body is encapsulated in the encapsulation layer 3; outside the encapsulation layer 3 and located in The lower surface of the connection layer 4 is provided with the connection layer 4 .

Liquid metal has the ability to develop under medical imaging equipment. Medical imaging device can identify liquid metal, so as to identify identifiable marks through image processing algorithms. At the same time, optical imaging device can identify identifiable marks through visible light imaging and image processing, so that medical imaging The device and the optical imaging device are able to identify and locate the liquid metal layer simultaneously.

The same liquid metal layer is used as an identifiable mark, and there are many kinds of characteristics that can be identified. For example, for an identifiable mark composed of a circle and a square, it has the center of the circle or the vertex of the square. At this time, there are two case:

The first is that the identifiable mark position of the medical imaging device and the identifiable mark position of the optical imaging device are the same position, like the center of a circle, or the corner point of the same square, so that the medical imaging device and the optical imaging device can simultaneously Identifying the liquid metal layer to enable tracking;

The second is that the medical imaging device can only recognize the center of the circle, while the optical imaging device can only recognize the vertices of the square, but it is known that there is a definite positional relationship between the center and the vertex. Liquid metal layer 1, so that tracking can also be achieved.

As shown in FIG. 2 , the liquid metal layer 1 has a specific shape or texture. Figure 2(a) is a checkerboard formed by a checkered array; the size of the checker is 15×15mm, and the thickness is 0.1-0.5mm. Figure 2(b) is a composite fan-shaped pattern of a ring, including two sectors inside the ring, the centers of the two sectors coincide at the center of the ring, and the angles and relative positions of the two sectors can be printed as required. Preferably, the outer diameter of the ring is 10-30 mm, the width of the ring is 3-5 mm, the sum of the opening angles of the two sectors is less than 360°, and the minimum acute angle formed by the two sectors is not less than 15°. The optical imaging device can obtain the spatial position coordinates of the center of the ring according to the corner points formed by the ring and the fan shape, and can uniquely identify the number of the center point according to the opening angle of the fan shape. The medical imaging device can also uniquely identify the center point in the pattern in the image. FIG. 2( c ) shows that the liquid metal layer 1 , the marker base layer 2 , the encapsulation layer 3 and the connection layer 4 are all made of flexible and stretchable materials. When in use, the liquid metal layer can be cut according to requirements or expanded by a combination of multiple identifiable marks. The size of a single mark is between 0.5 and 100mm, and the recognizable mark can be selected from the above-mentioned checkerboard pattern, fan-shaped or wafer pattern.

The tracking method of the liquid metal in vitro marker device for in vivo structure tracking of this embodiment, as shown in FIG. 3 , includes the following steps:

1) The liquid metal in vitro marker device 7 is placed on the surface of the imaging object 9 near the internal structure 8 to be tracked, and is connected to the surface of the imaging object through the connecting layer;

2) The liquid metal in vitro marker device 7 and the internal structure 8 of the imaging object 9 to be tracked are all located in the imaging field of view of the medical imaging device 6, and the medical imaging device 6 obtains the liquid metal layer and the internal structure 8 to be tracked. image;

3) Perform an image processing algorithm on the medical image to obtain the spatial positional relationship between the liquid metal layer and the internal structure 8 to be tracked. The spatial positional relationship includes the positional offset and attitude rotation between the internal structure to be tracked and the liquid metal layer. The spatial position relationship is a static relationship established directly through medical images, or a dynamic relationship with certain regularity established including medical images, patient breathing, and heartbeat signals;

4) The optical imaging device 5 performs image recognition and measurement on the identifiable mark of the liquid metal layer through the encapsulation layer, and obtains the spatial position and attitude in the coordinate system of the optical imaging device 5;

5) The spatial positional relationship between the liquid metal layer and the internal structure 8 to be tracked, and the spatial position and attitude of the liquid metal layer in the coordinate system of the optical imaging device 5, to realize the tracking of the spatial position and attitude of the internal structure 8 to be tracked.

Finally, it should be noted that the purpose of publishing the embodiments is to help further understanding of the present invention, but those skilled in the art can understand that various replacements and modifications can be made without departing from the spirit and scope of the present invention and the appended claims. It is possible. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims (10)

1. A liquid metal in vitro marker device for in vivo structure tracking, wherein the liquid metal in vitro marker device comprises: a liquid metal layer, a marker base layer, an encapsulation layer and a connection layer; wherein, the liquid metal layer The liquid metal is used to form a structure with a specific shape or texture as an identifiable mark. The liquid metal has the ability to develop under medical imaging equipment. The imaging device can identify identifiable marks through visible light imaging and image processing, so that medical imaging equipment and optical imaging equipment can identify the liquid metal layer at the same time; medical imaging equipment and optical imaging equipment can identify the liquid metal layer at the same time. Imaging rays and optical imaging equipment can simultaneously observe at least one identifiable mark position in the identifiable marks through visible light, and the identifiable mark position of the medical imaging equipment and the identifiable mark position of the optical imaging equipment are located at the same spatial position; the liquid metal layer It is arranged on the upper surface of the marker base layer to form a composite body; the composite body is encapsulated in the encapsulation layer and the connecting layer; the connecting layer is located on the lower surface of the marker base layer; The surface connection of the imaging object; the liquid metal in vitro marker device and the internal structure of the imaging object to be tracked are all located within the imaging field of view of the medical imaging device, and the medical imaging device obtains the liquid metal layer and the internal structure to be tracked. Medical images of the internal structure; Perform image processing algorithms on medical images to obtain the spatial relationship between the liquid metal layer and the internal structure to be tracked; the optical imaging device performs image recognition and measurement on the identifiable marks of the liquid metal layer through the encapsulation layer to obtain the coordinate system of the optical imaging device The spatial position and attitude of the internal structure to be tracked are realized through the spatial position relationship between the liquid metal layer and the internal structure to be tracked, and the spatial position and attitude of the liquid metal layer in the coordinate system of the optical imaging device to realize the spatial position and attitude of the internal structure to be tracked. track. 2 . The liquid metal in vitro marker device according to claim 1 , wherein the specific shape or texture structure of the liquid metal layer adopts one of a checkered array, a dot array and a spherical array. 3 . or a combination of multiple, or a single shape or array of shapes consisting of one or more of dots, line segments, arcs, polygons, sectors, circles and rings; the plane size of the single shape is 0.5 Between ~100mm, the shape accuracy is better than 0.5mm, and the thickness is between 0.1~1mm. 3. The liquid metal in vitro marker device according to claim 2, wherein the diameter of the dot is 1-10 mm, the line width of the line is 0.5-5 mm, and the diameter of the polygon, sector, circle and ring is 0.5-5 mm. The plane size is 2~100mm. 4 . The liquid metal in vitro marker device according to claim 1 , wherein the liquid metal is a low-melting metal element or a metal alloy with a melting point below 80° C. 5 . 5 . The liquid metal in vitro marker device according to claim 1 , wherein the liquid metal structure layer is formed on the upper surface of the marker base layer by a method of printing, coating, pouring, filling or inlaying. 6 . 6. The liquid metal in vitro marker device according to claim 1, wherein the marker base layer is a material with a low attenuation coefficient for medical imaging rays, and the marker base layer and the liquid metal have an optical imaging system distinguishable color difference. 7 . The liquid metal in vitro marker device according to claim 6 , wherein the marker base layer is one of polymer materials, paper, cloth, aluminum and aluminum alloys. 8 . 8 . The liquid metal in vitro marker device according to claim 1 , wherein the composite body is encapsulated in the encapsulation layer and the connection layer: the encapsulation layer wraps all surfaces of the composite body inside, and the encapsulation layer outside the encapsulation layer. 9 . A connection layer is arranged on the lower surface of the marker base layer; or, a connection layer is arranged on the lower surface of the marker base layer of the composite body, and an encapsulation layer is covered on the upper surface of the liquid metal layer, and the connection layer and the encapsulation layer together form an interior sealed space, The complex is encapsulated in an internally sealed space. 9 . The liquid metal in vitro marker device according to claim 1 , wherein the connection layer adopts a connection method of glue bonding, clamping, screw connection or electromagnetic connection, and the liquid metal layer, the marker base layer and the The encapsulation layer is attached to the surface of the imaged object. 10. A tracking method for a liquid metal in vitro marker device for in vivo structure tracking according to claim 1, wherein the tracking method comprises the following steps: 1) The liquid metal in vitro marker device is placed on the surface of the imaging object near the internal structure to be tracked, and is connected to the surface of the imaging object through the connecting layer; 2) The liquid metal in vitro marker device and the internal structure to be tracked of the imaging object are all located within the imaging field of view of the medical imaging device, and the medical imaging device obtains a medical image of the liquid metal layer and the internal structure to be tracked; 3) Perform an image processing algorithm on the medical image to obtain the spatial positional relationship between the liquid metal layer and the internal structure to be tracked; 4) The optical imaging device performs image recognition and measurement on the identifiable mark of the liquid metal layer through the encapsulation layer, and obtains the spatial position and attitude in the coordinate system of the optical imaging device; 5) Through the spatial position relationship between the liquid metal layer and the internal structure to be tracked and the spatial position and attitude of the liquid metal layer in the coordinate system of the optical imaging device, the tracking of the spatial position and attitude of the internal structure to be tracked is realized.

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