Registration method for body surface positioning device, puncture guidance method and device

Abstract

A registration method, a puncture guidance method and an apparatus for a body surface positioning device, the registration method includes acquiring image space coordinates of each tracking point of an optical tracking device arranged on the body surface (S1), collecting surgical space coordinates generated by the positioning device based on the current position of each tracking point of the optical tracking device (S2), determining a correspondence relationship in image space and surgical space of each tracking point based on the image space coordinates and the surgical space coordinates, and calculating a rotation matrix and / or a translation matrix (S3), and calculating registration error data of the optical tracking device based on the image space coordinates, the rotation matrix and the translation matrix of each tracking point (S4).

Description

[Technical Field]

[0001] The present invention relates to the field of medical image data processing, and more particularly to a registration method for a body surface positioning device, and a puncture guidance method and device. [Background technology]

[0002] The surgical navigation and positioning system can achieve positioning using an optical tracking method. The system is equipped with an optical tracking device, which is equipped with reflective beads. The optical system tracks the reflective beads to achieve real-time tracking and positioning of the target.

[0003] Currently, surgical navigation and positioning systems used clinically in the fields of orthopedics and neurosurgery fix tracking devices to the skeleton or skull frame to keep them fitted to the surgical site, and the navigation and positioning system tracks the corresponding tracking devices to position the surgical site.

[0004] The position of the chest or abdomen is subject to undulations caused by breathing, which can lead to variations in positioning. In a puncture procedure, the puncture route must first be determined based on CT images before surgery, and then the puncture must be performed according to the predetermined puncture route during surgery. However, due to the influence of the undulations of the body surface caused by breathing, the actual puncture route may differ from the predetermined puncture route, which is referred to as a registration error in this application. If the registration error is too large, the puncture needle will not be able to reach the target accurately, making it relatively difficult for doctors to perform the puncture procedure. Summary of the Invention [Means for solving the problem]

[0005] In view of this, the present invention provides a registration method for a body surface positioning device, wherein the body surface positioning device includes a plurality of tracking points, and the intervals between any pair of tracking points are different, and the method includes:

[0006] Obtaining image space coordinates of each tracking point of an optical tracking device disposed on the body surface;

[0007] collecting surgical space coordinates generated by a positioning device based on the current position of each tracking point on the optical tracking device;

[0008] determining a correspondence relationship between the image space and the surgical space of each of the tracking points based on the image space coordinates and the surgical space coordinates, and calculating a rotation matrix and / or a translation matrix;

[0009] calculating registration error data for the optical tracking device based on the image space coordinates of each of the tracking points, the rotation matrix, and the translation matrix.

[0010] Optionally, the image space coordinates are the three-dimensional coordinates in the computed tomography image data of each of the tracking points.

[0011] Optionally, the surgical space coordinates are three-dimensional coordinates provided by a multi-eye video camera capturing each of the tracking points.

[0012] Optionally, determining the correspondence of each tracking point in the image space and in the surgical space specifically includes:

[0013] Based on the image space coordinates, a distance matrix D Q and calculate a distance matrix D of each tracking point in the surgical space based on the surgical space coordinates. P and

[0014] distance matrix D Q and the distance matrix D P Calculating the distance of each column based on

[0015] and determining a correspondence between each of the tracking points in the image space and the surgical space based on the smallest element of each column in the error matrix M.

[0016] Alternatively, the distance matrix D Q and the distance matrix D P contains the distances between any pairwise tracking points.

[0017] Alternatively, the interval matrix D Q and the interval matrix D P Specifically, calculating the distance of each column based on

[0018] respectively, the interval matrix D Q and the interval matrix D P Arranging in ascending order,

[0019] Calculating the distance between each column in the two matrices arranged in ascending order to obtain an error matrix M.

[0020] Optionally, in the step of calculating registration error data of the optical tracking device based on the image space coordinates of each tracking point, the rotation matrix and the translation matrix, the registration error data FRE is calculated by the following formula:

[0021] JPEG0007743609000001.jpg8170

[0022] where n is the number of tracking points, and q i denotes the image space coordinate of the i-th tracking point, R denotes the translation matrix, and T denotes the rotation matrix.

[0023] Optionally, the tracking points are serially connected by flexible connecting members, allowing the surgical space coordinates of each tracking point to be changed independently.

[0024] The present invention further provides a puncture guidance method, which includes: calculating registration error data in at least one respiratory cycle of the subject to be punctured based on the above method, wherein the image space coordinates are fixed values ​​and the surgical space coordinates change according to the undulations of the body surface of the subject when breathing, making the registration error data dynamic values; determining the time corresponding to the minimum value of the registration error data; and guiding the puncture operation at the time.

[0025] The present invention further provides an electronic device comprising at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to perform the registration method for the body surface positioning device.

[0026] The present invention further provides an electronic device comprising at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor, and the instructions, when executed by the at least one processor, cause the at least one processor to perform the above-described puncture guidance method. [Effects of the Invention]

[0027] According to the registration method and puncture guidance method and device for the body surface positioning device, the calculated registration error data can numerically indicate the degree of conformity between the breathing posture of the human body and the breathing posture of the human body during the pre-operative CT scan, thereby enabling the doctor to perform the puncture procedure at the appropriate time and ensuring that the actual puncture path matches the predetermined puncture path, thereby reducing the difficulty of the puncture procedure and improving surgical efficiency. [Brief explanation of the drawings]

[0028] In order to more clearly describe the specific embodiments of the present invention or the technical solutions of the prior art, the following briefly describes the drawings necessary for describing the specific embodiments or the prior art. Obviously, the drawings described below are examples of the embodiments of the present invention, and those skilled in the art can further obtain other drawings based on these drawings without any creative efforts.

[0029] [Figure 1] FIG. 1 is a structural schematic diagram of an optical tracking device according to an embodiment of the present invention.

[0030] [Figure 2] FIG. 2 is a flowchart of a registration method for a body surface positioning device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The technical solutions of the present invention will be described clearly and completely below with reference to the drawings, but it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and any other embodiments that a person skilled in the art can obtain based on the embodiments of the present invention without any inventive work fall within the protection scope of the present invention.

[0032] Furthermore, unless they conflict with each other, the technical features relating to different embodiments of the present invention described below may be combined with each other.

[0033] The optical tracking device is placed on the surface of the human body, so it is also called a body surface positioning device. The compound eye video camera in the surgical navigation system collects the position of the optical tracking device, so that the position of the human body and the position where the puncture is to be performed can be accurately determined.

[0034] 1, this embodiment provides an optical tracking device for use in cooperation with an optical navigation positioning system, which may be an infrared light navigation positioning system or a visible light navigation positioning system, and the optical tracking device of this embodiment can be used for general purposes. Specifically, the optical tracking device of this embodiment includes two or more reflective bead assemblies and a plurality of body surface positioning tapes 3.

[0035] The reflective bead assembly is for positioning in cooperation with a surgical navigation positioning system. The operating principle of the reflective bead assembly for positioning in cooperation with a surgical navigation positioning system belongs to the well-known technology in the art, so a detailed description is omitted here.

[0036] The multiple body surface positioning tapes 3 have a soft structure, the number of body surface positioning tapes 3 is the same as the number of reflective bead assemblies, and two or more reflective bead assemblies are connected in sequence by the body surface positioning tapes 3 to form a closed loop.

[0037] In the preferred embodiment of the optical tracking device of the present invention, five sets of reflective bead assemblies are installed, corresponding to five body surface positioning tapes 3. It should be understood that, according to actual needs, those skilled in the art may adopt three, four, six, or seven sets of reflective bead assemblies, so that the number of body surface positioning tapes 3 is three, four, six, or seven.

[0038] In this embodiment, five sets of reflective bead assemblies are installed, and experiments have shown that five sets of beads can balance the requirements for accuracy and efficiency while simplifying the structure and algorithm.

[0039] As shown in Figure 1, every two of the five reflective bead assemblies are connected by one body surface positioning tape, and the five reflective bead assemblies are connected in sequence by the body surface positioning tape to form a closed loop. The present application does not specifically limit the relative positions of the five reflective bead assemblies and the length of the body surface positioning tape 3 connected between every two reflective bead assemblies, and these should be set according to actual needs.

[0040] In this embodiment, the use of a soft body surface positioning tape ensures that the basic shape of the entire positioning structure, which is made up of multiple positioning structures, is fixed, while the soft material allows each positioning structure to move independently. The advantage of this is that when the body surface positioning tape fits the skin surface, the positioning structures can move dynamically in accordance with the body surface, allowing the movement range of the skin surface to be dynamically tracked, thereby realizing dynamic navigation positioning and solving the problem that conventional rigid positioning devices can only track statically.

[0041] To further improve the dynamic positioning effect, in this embodiment, the body surface positioning tape 3 has an elastic, soft structure. Preferably, in this embodiment, the body surface positioning tape 3 is made of a silicone rubber tape. However, it should be understood that any body surface positioning tape 3 made of an elastic, soft material is within the scope of protection of the present application. The body surface positioning tape 3 has a soft structure and is made of silicone rubber, which has good biocompatibility, high adsorption force, and can flexibly adjust to the human body, so that the positioning structures connected to both ends of the body surface positioning tape 3 can be applied to the body surface and fit the skin.

[0042] To ensure that the dynamic positioning device for body surface of this embodiment fits well on the corresponding human body surface when placed on the corresponding human body surface and improve the accuracy of dynamic positioning on the body surface, in this embodiment, the underside of the body surface positioning tape 3 is flush with the underside of the positioning structure, so that the undersides of the body surface positioning tape 3 and the positioning structure fit tightly on the body surface. Furthermore, making the underside of the body surface positioning tape 3 flush with the underside of the positioning structure also makes it easier to later fix the body surface positioning tape 3 with medical tape, further facilitating real-time tracking and positioning.

[0043] The connection between the reflective bead assembly and the body surface positioning tape 3 may be by fastening, screw connection, hot melt adhesive or other fixed connection methods. In the preferred embodiment of the present application, the reflective bead assembly includes a body surface base 5, a bead fixing seat 2 and a bead fixing pole 4,

[0044] The body surface base 5 is for connecting the body surface positioning tape 3, and the lower surface of the body surface base 5 is flush with the lower surface of the body surface positioning tape 3 to be connected thereto, and a limiting groove 6 is formed in the body surface base 5;

[0045] The body surface base 5 has a cylindrical structure and is used to connect the body surface positioning tapes 3. The body surface bases 5 and the body surface positioning tapes 3 are the same in number and are connected to each other in order to form a closed loop. The body surface positioning tapes 3 are connected to the outer surface of the body surface base 5, and in order to fit the skin, the underside of the body surface base 5 is flush with the underside of the body surface positioning tapes 3 connected to it.

[0046] At the same time, a restricting groove 6 for attaching the bead fixing seat 2 is formed on the upper surface of the body surface base 5,

[0047] The bead fixing seat 2 is for attaching the reflective bead 1, and the bead fixing seat 2 is attached in the limiting groove 6, and its structure is compatible with the limiting groove 6;

[0048] The bead fixing pole 4 is inserted into the bead fixing seat 2 to fix the bead fixing seat 2 and the body surface base 5. The bead fixing pole 4 may be an assembly such as a bolt, which penetrates the bottom of the restricting groove 6 and is inserted from below to connect to the bead fixing seat 2 which engages in the restricting groove 6. The connection method may also be such that a screw hole is simultaneously provided on the underside of the bead fixing seat 2, and the bead fixing pole 4 is inserted through the through hole and screwed into the screw hole provided on the underside of the bead fixing seat 2.

[0049] The surgical navigation system and the optical tracking device can track the respiratory motion of the human body. An embodiment of the present invention provides a method for registering a body surface positioning device, which may be performed by an electronic device such as a computer or a server, and as shown in Figure 2, the method includes the following steps:

[0050] S1: Obtain image space coordinates of each tracking point in the optical tracking device placed on the body surface. The tracking points in this embodiment may be, but are not limited to, the reflective beads in the above embodiments. Specifically, before surgery, a human body part wearing an optical tracking device may be scanned using computer tomography to obtain CT image data (three-dimensional), and then the location of each tracking point therein may be identified to obtain its spatial coordinates in the CT image data. These spatial coordinates are called image space coordinates, and these data are static values. In a specific embodiment, the optical tracking device has five tracking points, and the image space coordinates are written as Q = [q1, q2, q3, q4, q5], where q1...q5 represent the three-dimensional coordinates of the five tracking points.

[0051] S2: Collect surgical space coordinates generated by the positioning device based on the current position of each tracking point on the optical tracking device. Specifically, during surgery, the positioning device (a navigational compound-eye video camera) can track the current position of each tracking point to obtain its coordinate in the surgical space. These coordinates are called surgical space coordinates. Because the optical tracking device moves with the respiratory undulations of the human body, the surgical space coordinates are dynamic values ​​that change with the person's breathing. In a specific embodiment, the optical tracking device has five tracking points, and the surgical space coordinates are written as P = [p1, p2, p3, p4, p5], where p1...p5 represent the three-dimensional coordinates of the five tracking points.

[0052] S3: Determine the correspondence between each tracking point in the image space and the surgical space based on the image space coordinates and the surgical space coordinates, and calculate the rotation matrix and / or translation matrix. The image coordinates and surgical space coordinates of each tracking point in the optical tracking device are randomly arranged, so it is necessary to identify the correspondence between each tracking point in the two spaces for real-time tracking registration. Because the pairwise distances between any two tracking points in the optical tracking device are different, matching can be performed based on the discrepancy in inter-point distances to determine the corresponding matching points. Because the scanning and shooting orientations of the same target by the CT scanner and the compound-eye video camera are different, after determining the correspondence, it is necessary to further calculate the rotation matrix and / or translation matrix. The algorithm for calculating the rotation matrix and translation matrix for the two coordinate systems is well known, and a detailed description is omitted here.

[0053] S4: Calculate the registration error data of the optical tracking device based on the image space coordinates, rotation matrix, and / or translation matrix of each tracking point. This registration error data characterizes the degree of conformance between the current (intraoperative) respiratory posture of the human body and the respiratory posture of the human body at the time of the preoperative CT scan. For example, the smaller the error data, the better the conformance. There are various specific calculation methods, for example, the registration error data can be calculated for each tracking point, and then the maximum, minimum, average, etc. can be taken.

[0054] The registration error data calculated based on the registration method of the body surface positioning device according to the embodiment of the present invention can numerically indicate the degree of conformity between the breathing posture of the human body and the breathing posture of the human body during the pre-operative CT scan, thereby enabling the doctor to perform the puncture procedure at the appropriate time, ensuring that the actual puncture path is consistent with the predetermined puncture path, reducing the difficulty of the puncture procedure, and improving surgical efficiency.

[0055] In a preferred embodiment, in the case of a body surface positioning tape made of a flexible material, in step S4, specifically, the registration error data FRE is calculated by the following formula:

[0056] JPEG0007743609000002.jpg8170

[0057] where n is the number of tracking points (e.g., n=5), and q i where denotes the image space coordinate of the i-th tracking point, R denotes the translation matrix, and T denotes the rotation matrix. The registration error data calculated by this solution has relatively high accuracy and can more accurately reflect the difference between the respiratory undulations of the body surface during surgery and the respiratory undulations during the pre-operative image scan.

[0058] Regarding the matching method between the tracking points in the surgical space and the tracking points in the image space in step S3, the present application provides a suitable matching method.

[0059] S31: Calculate the distance between the pairwise tracking points in the surgical space and the distance between the pairwise tracking points in the image space. For example, if there are five tracking points, the distance (Euclidean distance) between the i-th tracking point and the other tracking points in the surgical space is d pi =[||p i -p1||…||p i -p5||], where i=1...5, and the distance between the ith tracking point and other tracking points in image space is d qi =[||q i -q1||…||qi -q5||], where i = 1...5.

[0060] This gives the distance matrix D for each tracking point in the image space. Q and the distance matrix D of each tracking point in the surgical space P You can get D P =[d p1 d p2 d p3 d p4 d p5 ], D Q =[d q1 d q2 d q3 d q4 d q5 ].

[0061] S32 Distance matrix D Q and the distance matrix D P In a preferred embodiment, the distance matrix D is calculated based on the distances of each column to obtain the error matrix M. Q and the interval matrix D P Arrange in ascending order, JPEG0007743609000003.jpg8170The distance m between each column in the two matrices arranged in ascending order is then calculated. ij The calculation formula is:

[0062] m ij =||d pj -d qi || and

[0063] where d pj is the distance matrix D Q Denote the jth column in d qi is the distance matrix D P The calculated distance between each column in the two matrices constitutes the error matrix M.

[0064] S33: Determine the correspondence between each tracking point in the image space and the surgical space based on the smallest element in each column of the error matrix M. The error matrix M obtained for the five tracking points is a 5*5 dimensional matrix, and the smallest element in each column of the matrix M is searched for. For example, if the ith element in the jth column is the smallest, then the jth tracking point p in the point set P is determined. j is the i-th tracking point q in the point set Q i In this way, we can obtain the matching correspondence of all tracking points in the two point sets.

[0065] Based on the above embodiment, another embodiment of the present invention provides a puncture guidance system, which includes a positioning device (such as a compound eye video camera and a processor), a puncture device (such as a robotic arm and a puncture needle-grasping structure member), and an optical tracking device, and the puncture guidance system is configured to perform operations including:

[0066] According to the registration method of the above embodiment, the registration error data of at least one respiratory cycle of the puncture subject is calculated in real time, and the image space coordinates are fixed values, while the operating space coordinates change according to the body surface undulations during the puncture subject's breathing, making the registration error data dynamic values;

[0067] This allows obtaining an error curve in which the registration error data FRE changes periodically over time, and the time period during which the error curve changes corresponds to the person's respiratory cycle. In one respiratory cycle, the smallest error value indicates that the person's current respiratory state best matches the respiratory state of the pre-operative scan image.

[0068] The system determines the time corresponding to the minimum value of the registration error data and guides the physician to perform the puncture operation at that time. When the puncture device is aligned with the puncture site, the system can guide the physician to perform the puncture based on the registration error data, thereby effectively reducing positioning errors caused by respiratory deformation. A specific guidance operation can be an audio notification, for example, an audio notification of the magnitude of the registration error value at the current time, or an audio notification when the registration error data is smaller than a predetermined threshold, thereby prompting the physician to insert the puncture needle into the human body at the appropriate time.

[0069] Those skilled in the art should understand that embodiments of the present invention may be provided as a method, a system, or a computer program product. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. The present invention may also take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, magnetic disk memory, CD-ROM, optical memory, etc.) containing computer-usable program code.

[0070] The present invention has been described with reference to flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, and combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, whereby the instructions, executed by the processor of the computer or other programmable data processing apparatus, create an apparatus that implements the functions specified in one or more processes of the flowcharts and / or one or more blocks of the block diagrams.

[0071] These computer program instructions may be stored in a computer-readable memory that can be directed to cause a computer or other programmable data processing apparatus to operate in a particular manner, whereby the instructions stored in the computer-readable memory create an article of manufacture that includes an instruction apparatus that implements the functions specified in one or more processes of the flowcharts and / or one or more blocks of the block diagrams.

[0072] These computer program instructions may be loaded into a computer or other programmable data processing apparatus to cause the computer or other programmable apparatus to perform a series of operational steps to produce a computer-implemented process, whereby the instructions executing on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more processes of the flowcharts and / or one or more blocks of the block diagrams.

[0073] Obviously, the above examples are merely examples for clarity and explanation, and are not intended to limit the embodiments. Those skilled in the art can make other different types of changes or modifications based on the above description. It is not necessary or possible to list all the embodiments here. Any obvious changes or modifications derived therefrom still fall within the scope of protection of the invention.

Claims

1. 1. A method for registering an optical tracking device placed on a body surface, comprising: The optical tracking device includes a plurality of tracking points, and the intervals between any pair of tracking points are different; The method comprises the steps of: acquiring, for the plurality of tracking points, image space coordinates of each tracking point based on computed tomography image data while the optical tracking device is positioned on the body surface of the subject; acquiring surgical space coordinates of each of the plurality of tracking points based on the current positions of the tracking points photographed by the compound eye video camera; determining a correspondence relationship between the plurality of tracking points in the image space and the surgical space based on the image space coordinates and the surgical space coordinates, and calculating a rotation matrix (R) and a translation matrix (T) for correcting the rotation and translation of coordinate axes; calculating registration error data based on the image space coordinates of the plurality of tracking points, the rotation matrix, and the translation matrix, wherein the registration error data FRE is calculated by the following formula: where n is the number of tracking points, and q ｉ denotes the image space coordinate of the i-th tracking point, R denotes the translation matrix, and T denotes the rotation matrix; 1. A method for registering an optical tracking device, comprising:

2. The step of determining correspondences of the plurality of tracking points in the image space and the surgical space includes: Based on the image space coordinates, a distance matrix D containing pairwise distances for each tracking point in image space is calculated. Ｑ Calculate Based on the surgical space coordinates, a distance matrix D containing pairwise distances of each tracking point in the surgical space is calculated. Ｐ Calculate The distance matrix D Ｑ and the distance matrix D Ｐ Based on the above, an error matrix M is obtained from the distance difference of each column. determining a correspondence relationship between the plurality of tracking points in the image space and the surgical space based on the minimum value of each column in the error matrix M; The method of claim 1 ,

3. The distance matrix D Ｑ and the distance matrix D Ｐ The step of obtaining the error matrix M based on The distance matrix D Ｑ and the distance matrix D Ｐ Each element is sorted in ascending order, Calculate the difference between corresponding elements of the two matrices arranged in ascending order for each column to obtain the error matrix M.

3. The method of claim 2.

4. 4. The method according to claim 1, wherein the plurality of tracking points are connected in series by a flexible connecting member, allowing the surgical space coordinates of each tracking point to be changed independently.

5. An electronic device, at least one processor and a memory communicatively coupled to the processor; The processor executes the instructions stored in the memory, An electronic device that executes the registration method according to any one of claims 1 to 4.

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