Interventional imaging catheter and six-degree-of-freedom positioning method, system, equipment and medium thereof

Abstract

For interventional surgery, robot-assisted operation and image guidance are urgently required clinically. However, due to limitation of size, magnetic component interference and the like, tracking and positioning of magnetic imaging catheters in IVUS and OCT forms are difficult problems. The interventional imaging catheter, the six-degree-of-freedom positioning method, the six-degree-of-freedom positioning system, the six-degree-of-freedom positioning equipment and the medium are different from a magnetic positioning method of a transmission embedded sensor, and the interventional imaging catheter is compatible with a magnetic part in a permanent magnet rotor form. Meanwhile, in cooperation with a magnetic positioning search strategy for linearly solving an initial value, positioning of the catheter can be rapidly achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an interventional imaging catheter and a six-degree-of-freedom positioning method, system, equipment, and medium thereof. Background Art

[0002] Vascular diseases are prevalent worldwide, and their incidence is increasing due to an aging population and changing lifestyles. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) are two key intravascular imaging technologies commonly used for the diagnosis and treatment of coronary artery disease. They can provide high-resolution cross-sectional images of the vessel wall, allowing clinicians to accurately assess plaque composition, the degree of vascular stenosis, and the effectiveness of stent deployment. However, traditional IVUS and OCT systems utilize external motors and flexible metal shafts to rotate the imaging probe. In complex vascular environments, their performance may be limited by catheter stiffness and non-uniform rotational distortion (NURD) artifacts. To address these limitations, some researchers have developed magnetically driven imaging catheters. This innovation not only significantly enhances the flexibility of the catheter, but also reduces radiation exposure and eases the operator's operation when combined with an intraoperative navigation system.

[0003] However, tracking and maneuvering millimeter-scale magnetic catheters in vascular environments remains a technical challenge. This determines whether the catheter can respond to magnetic fields as expected, which is crucial for operational safety. Considering system compatibility and complexity, magnetic positioning methods, due to their high adaptability, offer significant advantages in the navigation of magnetic interventional devices. Based on the relationship between the tracking target and the sensor, magnetic positioning methods can be broadly categorized into two types: magnetic field cameras (MFCs) and Hall-effect sensors. The former uses an external integrated magnetic sensor array to detect permanent magnets within the target device. The latter directly tracks embedded Hall-effect sensors and combines them with sensor fusion algorithms to achieve robot positioning. While these advances are encouraging, their applicable sizes are mostly in the millimeter to centimeter range, primarily targeting capsule robotics operating in the intestine. Recent research has demonstrated magnetic positioning of small catheters (3 mm) for steering tasks within electromagnetic navigation systems. Existing magnetic positioning systems cannot meet the clinical needs of smaller vessels, such as the radial artery, where catheter sizes are approximately 5 to 6 Fr (1 Fr = 0.33 mm).

[0004] To achieve beam scanning, magnetic catheters used for imaging often utilize a "rotor + mirror" structure for their internal magnetic components. The small size of these magnetic components makes them incompatible with MFC positioning methods, and the magnetic field interference generated by rotation on algorithms that utilize magnetic field positioning is difficult to eliminate. In summary, magnetic field positioning for intravascular magnetically driven interventional imaging catheters remains a difficult problem. Developing appropriate magnetic positioning strategies and algorithms to address vessel size limitations and magnetic component interference is a pressing need in intravascular interventional robotics engineering. Summary of the Invention

[0005] In order to achieve the above-mentioned objectives and other advantages of the present invention, a first object of the present invention is to provide a six-degree-of-freedom positioning method for an interventional imaging catheter, wherein the interventional imaging catheter includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The method includes the following steps:

[0006] Controlling the external magnetic field generating device to rotate around the rotating shaft to generate a driving magnetic field, wherein the magnetic rotor component is acted upon by magnetic force and torque in the magnetic field, thereby driving the reflector to rotate to achieve axial scanning of the beam, thereby achieving catheter imaging;

[0007] During the driving process, the composite magnetic field information of the external magnetic field generating device and the magnetic rotor component detected by the Hall magnetic field sensor array is obtained;

[0008] Processing the sampled data of the Hall magnetic field sensor array to obtain a sampled magnetic field of the external magnetic field generating device after removing interference;

[0009] Calculate the spatial magnetic field at any position of the interventional imaging catheter and obtain a rotating field model;

[0010] Processing the sampled magnetic field of the external magnetic field generating device to obtain the required eigenvector and corresponding driving angle;

[0011] The rotating field model is used to obtain the relationship between the maximum and minimum values ​​of the magnetic field of a spatial point on the plane and the plane positioning result, and the plane positioning result is converted to the actual position;

[0012] The posture matrix at the robot's plane position is solved based on the relationship between the model ellipse data and the sampled ellipse data, and then it is rotated to the posture at the actual section point.

[0013] Furthermore, the step of processing the sampled data of the Hall magnetic field sensor array to obtain the external magnetic field generating device driving magnetic field sampling after removing interference includes:

[0014] Performing difference processing on the sampled data to obtain the magnetic vector of the magnetic rotor component in the plane;

[0015] B subtract =B sensor1 -B sensor2

[0016] Among them, B sensor1 is the sampling data of the first Hall magnetic field sensor, B sensor2 is the sampling data of the second Hall magnetic field sensor;

[0017] According to the 2D angle perception of the magnetic rotor component by the Hall magnetic field sensor array, the encoding angle of the magnetic rotor component in the YZ plane of the Hall magnetic field sensor array is:

[0018] φ=tan -1 (-b z ,-b y )

[0019] Among them, b z , b y B subtract Vector components in the YZ plane;

[0020] Select the composite magnetic field B sampled by the second Hall magnetic field sensor far away from the magnetic rotor component sensor2 , the rotating magnetic vector of the magnetic rotor component in the plane of the Hall magnetic field sensor array is separated according to the following formula to obtain the driving field sampling of the external magnetic field generating device after removing the interference:

[0021] B=B sensor2 +k[0;cosφ;sinφ]

[0022] Wherein, k is the magnetic field amplitude of the magnetic rotor component at the second Hall magnetic field sensor.

[0023] Furthermore, the rotation field model is:

[0024]

[0025] Where μ0 is the vacuum magnetic permeability, (x, y, z) is the position on the interventional imaging catheter, θ is the motor angle, and M is the magnetic moment of the external magnetic field generating device.

[0026] Furthermore, the step of processing the sampled magnetic field of the external magnetic field generating device to obtain the required characteristic vector and the corresponding driving angle includes:

[0027] The rotation axis vector of the ellipse sensor is obtained by using singular value decomposition to sample the magnetic field of the external magnetic field generating device:

[0028] N=SVD(B(1),B(2),···,B(n))

[0029] Among them, B(1), B(2), ···, B(n) are the sampling magnetic fields of the external magnetic field generating device;

[0030] Perform a Rodriguez transformation on the rotation axis vector to obtain the transformation matrix to transform the three-dimensional ellipse to the XY plane to simplify subsequent operations:

[0031] R transform =Rodrigues(N,[0;0;1])

[0032] Among them, R transform is the transformation matrix;

[0033] In the ellipse fitting function, the transformation matrix transforms the 3D sample data B into 2D data, and the inverse matrix (R transform ) T Restore and finally get the required eigenvector and corresponding driving angle: the major and minor axis vectors B of the elliptical sensor max , B min and the motor angle θ at the corresponding sampling moment max ,θ min , the ellipse fitting function is:

[0034] [B min ,θ max ,B min ,θ min ]=ellipsefitting(B,R transoform ,θ)

[0035] Wherein, θ=[θ(2),θ(2),...,θ(n)] is the motor rotation angle at the time corresponding to the sampling magnetic field.

[0036] Furthermore, the step of using the rotating field model to obtain the relationship between the maximum and minimum values ​​of the magnetic field of a spatial point on the plane and the plane positioning result, and converting the plane positioning result to the actual position includes:

[0037] Assuming that the robot is located in the XZ plane, the rotation field model is used to obtain the relationship between the maximum and minimum values ​​of the magnetic field at a spatial point on the plane and the plane positioning result (x0,0,z0):

[0038]

[0039] Limit the solution space to the 1 / 4 sphere area, and the actual sensor sampling B max Appears at the two major axes of the ellipse, and the θ corresponding to the maximum value obtained by solving the ellipse fitting function max The solution space constraint should also be met: if Take θ max =-θ max ,θ max =θ max -180°;

[0040] Assuming the position section is the XZ plane, according to the magnetic field and the rotation angle of the corresponding external magnetic field generating device, the angle difference between the actual plane and the assumed plane is △θ = θ max -90°, the plane positioning result (x0,0,z0) is converted to the actual position P:

[0041] P=[x,y,z]=rotx(Δθ)[x0;0;z0].

[0042] Furthermore, the step of solving the posture matrix at the robot's plane position according to the relationship between the model ellipse data and the sampled ellipse data and then rotating it to the posture at the actual section point includes:

[0043] From the model ellipse data to the sampling ellipse data, the following conditions are satisfied:

[0044] R·b=B

[0045] Where R is the posture matrix of the robot in the tool coordinate system;

[0046] The residual square sum function is used to solve the attitude matrix:

[0047]

[0048] Among them, (x, y, z) is the actual position solution;

[0049] The solution of the robot posture matrix is ​​converted into the solution of the unit eigenvector transformation matrix corresponding to the ellipse using the residual square sum function:

[0050]

[0051] in, are the model vector ellipse major axis and rotation axis unit vectors;

[0052] Assume that the robot is in the XZ plane to simplify the difficulty of solving the posture matrix. At this time, the ellipse eigenvector at the plane (x0,0,z0) satisfies:

[0053] a=[3x0z0;0;2z0 2 -x0 2 ],n=[x0 2 -2z0 2 ;0;3x0z0]

[0054] Substitute the equation for the unit eigenvector transformation matrix corresponding to the ellipse to solve the posture matrix R0 at the robot's plane position, then rotate it to the posture R at the actual section point (x, y, z), and express the robot posture as the corresponding Euler angle (α, β, γ):

[0055]

[0056] The second object of the present invention is to provide an interventional imaging catheter, which uses the above method and includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The magnetic rotor component is used to drive the reflector to move synchronously with an extracorporeal magnetic field generating device, and the Hall magnetic field sensor array is used to collect three-axis spatial magnetic fields in real time.

[0057] A third object of the present invention is to provide an interventional imaging system, applying the above-mentioned method, comprising an interventional imaging catheter and an external magnetic field generating device, wherein the interventional imaging catheter includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array, wherein the external magnetic field generating device serves as a system magnetic source for generating a driving magnetic field for the interventional imaging catheter, and wherein the positioning range is highly consistent with the spatial location of the external magnetic field generating device; the external magnetic field generating device rotates around a rotation axis to generate a driving magnetic field, and the magnetic rotor component in the interventional imaging catheter is subjected to magnetic force and torque in the magnetic field, driving the reflector to rotate to achieve axial scanning of the beam, thereby achieving catheter imaging; and during the driving process, the Hall magnetic field sensor array detects the composite magnetic field information of the external magnetic field generating device and the magnetic rotor component.

[0058] A fourth object of the present invention is to provide a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0059] A fifth object of the present invention is to provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0060] Compared with the prior art, the present invention has the following beneficial effects:

[0061] Robot-assisted operation and image guidance are urgently needed clinically for interventional procedures. However, due to limitations such as size and interference from magnetic components, tracking and positioning of IVUS and OCT magnetic imaging catheters are challenging. This paper proposes a six-degree-of-freedom magnetic positioning method for interventional magnetic-driven catheters. Unlike magnetic positioning methods that use embedded sensors, this method is compatible with magnetic components in the form of permanent magnet rotors. Furthermore, a magnetic positioning search strategy using a linear solution for initial values ​​allows for rapid catheter positioning.

[0062] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0064] Figure 1 This is a schematic diagram of a magnetic interventional imaging catheter;

[0065] Figure 2The working diagram of the magnetic conduit and the principle diagram of magnetic field preprocessing;

[0066] Figure 3 is the elliptical vector magnetic field diagram excited by the rotating dipole in space;

[0067] Figure 4 A flow chart of a six-degree-of-freedom positioning method for an interventional imaging catheter;

[0068] Figure 5 A schematic diagram of a computer device;

[0069] Figure 6 A schematic diagram of a computer-readable storage medium. DETAILED DESCRIPTION

[0070] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. It should be noted that, without conflict, the embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0071] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0072] The figure numbers in this application are only used to distinguish the various steps in the scheme and are not used to limit the execution order of the various steps. The specific execution order is subject to the description in the specification.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0074] The present invention proposes an interventional imaging catheter and its six-degree-of-freedom (DOF) positioning method and system. A rotating external permanent magnet (EPM) is used as the system's magnetic source to generate the catheter's driving magnetic field, and the positioning range is highly consistent with the spatial location of the EPM. A Hall sensor array is integrated at the front end of the catheter to capture the three-axis spatial magnetic field in real time. This design eliminates interference with the magnetic source caused by magnetic components in the catheter. In addition, the present invention also provides a 6DOF positioning method based on the geometric characteristics of the rotating magnetic field. The specific scheme is as follows:

[0075] Example 1

[0076] An interventional imaging catheter includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The magnetic rotor component is used to drive the reflector and an extracorporeal magnetic field generating device to move synchronously, and the Hall magnetic field sensor array is used to collect spatial three-axis magnetic fields in real time.

[0077] In some embodiments, as Figure 1 As shown, interventional imaging catheters include, but are not limited to, an IVUS imaging catheter 10 and an OCT imaging catheter 20. The core components of the IVUS imaging catheter 10 include an outer sheath 11 for confining a miniature radially magnetized permanent magnet 12 and transmitting an ultrasonic beam, an acoustic reflector 13, an ultrasonic transducer 17, miniature three-axis Hall effect sensor arrays 14 and 15, and a circuit board 16 for securing the sensors. The core components of the OCT catheter 20 include an outer sheath 21 for confining a radially magnetized miniature permanent magnet 22 and transmitting a near-infrared beam, an optical reflector 23, an optical fiber 27, miniature three-axis Hall effect sensor arrays 24 and 25, and a circuit board 26 for securing the sensors.

[0078] The six-degree-of-freedom positioning method of the interventional imaging catheter provided by the present invention is as follows Figure 2-Figure 3 As shown, you can refer to the corresponding description in the following method embodiment, which will not be repeated here.

[0079] Example 2

[0080] An interventional imaging system, such as Figure 2 As shown, it includes the above-mentioned interventional imaging catheter 4 and the external magnetic field generating device 3. The interventional imaging catheter includes a magnetic rotor component (4-1), a reflector, and a Hall magnetic field sensor array (4-2 and 4-3). For a detailed description of the interventional imaging catheter, please refer to the corresponding description in the above-mentioned interventional imaging catheter embodiment, and no further details will be given here. The external magnetic field generating device serves as a system magnetic source to generate a driving magnetic field for the interventional imaging catheter, and the positioning range is highly consistent with the space where the external magnetic field generating device is located; the external magnetic field generating device rotates around the rotation axis to generate a driving magnetic field, as shown in FIG. Figure 2 The driving device 1 drives the motor 2 to drive the external magnetic field generating device 3 to generate a driving magnetic field by rotating around the rotating axis. The magnetic rotor component in the interventional imaging catheter is affected by the magnetic force and torque in the magnetic field, driving the reflector to rotate to achieve axial scanning of the beam, thereby realizing catheter imaging; during the driving process, the Hall magnetic field sensor array detects the composite magnetic field information of the external magnetic field generating device and the magnetic rotor component.

[0081] In some embodiments, the external magnetic field generating device may be an external permanent magnet, or other magnetic field generating devices, such as an electromagnetic coil array system.

[0082] The six-degree-of-freedom positioning method of the interventional imaging system provided by the present invention is as follows Figure 2-Figure 3As shown, you can refer to the corresponding description in the following method embodiment, which will not be repeated here.

[0083] Example 3

[0084] A six-degree-of-freedom positioning method for an interventional imaging catheter, such as Figure 2-Figure 3 As shown, the interventional imaging catheter includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The method includes the following steps:

[0085] S100, controlling the external magnetic field generating device to rotate around the rotation axis to generate a driving magnetic field, wherein the magnetic rotor component is subjected to magnetic force and torque in the magnetic field, driving the reflector to rotate to achieve axial scanning of the beam, thereby achieving catheter imaging;

[0086] S200, during the driving process, obtaining composite magnetic field information of the external magnetic field generating device and the magnetic rotor component detected by the Hall magnetic field sensor array (4-2 and 4-3);

[0087] S300, processing the sampled data of the Hall magnetic field sensor array to obtain a sampled magnetic field of the external magnetic field generating device after removing interference;

[0088] In some embodiments, the step of processing the sampled data of the Hall magnetic field sensor array to obtain the external magnetic field generating device driving magnetic field sampling after removing interference includes:

[0089] Performing difference processing on the sampled data to obtain the magnetic vector of the magnetic rotor component in the plane;

[0090] B subtract =B sensor1 -B sensor2

[0091] Among them, B sensor1 is the sampling data of the first Hall magnetic field sensor, B sensor2 is the sampling data of the second Hall magnetic field sensor;

[0092] According to the 2D angle perception of the magnetic rotor component (4-1) by the Hall magnetic field sensor array, the encoding angle of the magnetic rotor component in the YZ plane of the Hall magnetic field sensor array is:

[0093] φ=tan -1 (-b z ,-b y )

[0094] Among them, b z , b y B subtract Vector components in the YZ plane;

[0095] After the robot packaging is completed, the relative positions of the magnetic rotor component and the Hall magnetic field sensor array are fixed, and the interference of the rotation of the magnetic rotor component on the magnetic field collected by the Hall magnetic field sensor array is completely predictable. The composite magnetic field B sampled by the second Hall magnetic field sensor (4-3) far away from the magnetic rotor component is selected. sensor2 , the rotating magnetic vector of the magnetic rotor component in the plane of the Hall magnetic field sensor array is separated according to the following formula to obtain the driving field sample B of the external magnetic field generating device after removing the interference:

[0096] B=B sensor2 +k[0;cosφ;sinφ]

[0097] Wherein, k is the magnetic field amplitude of the magnetic rotor component at the second Hall magnetic field sensor, which can be measured in advance.

[0098] Existing studies have demonstrated that the rotating magnetic field generated by a rotating magnetic dipole fluctuates elliptically at every point in space, e.g. Figure 3 In the system, the rotation angle θ of the external magnetic field generating device is measured by a magnetic encoder arranged on its rotating shaft. The magnetic dipole model formula is used to accurately describe the elliptical magnetic field:

[0099]

[0100] Where Dipole is the magnetic field distribution at the target point; μ0 is the vacuum permeability; r is the relative displacement vector from the center of the permanent magnet to the target position; I is the unit matrix; and M is the magnetic moment of the permanent magnet.

[0101] S400, calculating the spatial magnetic field at any position of the interventional imaging catheter to obtain a rotating field model;

[0102] In this embodiment, the tool coordinate system is established with the center of the external magnetic field generating device as the origin, the motor shaft as the X-axis, and the encoder zero position as the positive direction of the Y-axis. The spatial magnetic field (i.e., the rotating field model) at any position (x, y, z) of the catheter is expressed as:

[0103]

[0104] Where (x, y, z) is the position on the interventional imaging catheter, θ is the motor rotation angle, M is the magnetic moment of the external magnetic field generating device,

[0105] In practice, it is found that the magnetic field ellipse has the following characteristics: 1. Shape characteristics: It is independent of the sensor posture, and the position determines the shape of the ellipse (the size of the major axis and minor axis); 2. Peak field alignment characteristics: The maximum value of the magnetic field B maxAs the external magnetic field generator rotates, it always appears in the plane formed by its axis and the magnetic poles. Combining the magnetic field collected by the sensor and recognizing the strong connection between the robot's posture and elliptical geometry, this example first identifies the characteristics of the elliptical sensor and designs a 6-DOF positioning strategy based on these geometric features.

[0106] S500, processing the sampled magnetic field of the external magnetic field generating device to obtain the required eigenvector and corresponding driving angle;

[0107] If the sampled magnetic field of the external magnetic field generating device obtained after preprocessing is specified as B(1), B(2), ···, B(n), where n is the number of readings, the rotation axis vector N of the elliptical sensor can be quickly obtained using singular value decomposition (SVD):

[0108] N=SVD(B(1),B(2),···,B(n))

[0109] Then, perform Rodrigues transformation on N to obtain the transformation matrix R transform Transform the 3D ellipse to the XY plane to simplify subsequent operations:

[0110] R transform =Rodrigues(N,[0;0;1])

[0111] In the ellipse fitting function, the transformation matrix R transform The 3D sample data B is transformed into 2D data and the inverse matrix (R transform ) T Restore and finally get the required eigenvector and corresponding driving angle: the major and minor axis vectors B of the elliptical sensor max , B min and the motor angle θ at the corresponding sampling moment max ,θ min , the ellipse fitting function is:

[0112] [B min ,θ max ,B min ,θ min ]=ellipsefitting(B,R transoform ,θ)

[0113] Wherein, θ=[θ(2),θ(2),...,θ(n)] is the motor rotation angle at the time corresponding to the sampling magnetic field.

[0114] The above discussion and sampling analysis of the elliptical magnetic field yields characteristic quantities and driving information that can describe the magnetic field. Next, we solve for position (x, y, z) and attitude (α, β, γ).

[0115] S600, using the rotating field model to obtain a relationship between the maximum and minimum values ​​of the magnetic field of a spatial point on a plane and a plane positioning result, and converting the plane positioning result to an actual position;

[0116] Based on the elliptical shape matching characteristics and peak field alignment characteristics, this embodiment first analyzes the magnetic positioning process on the cross section: Assuming that the robot is located in the XZ plane (y = 0), the above-mentioned rotating field model is used to obtain the relationship between the maximum and minimum magnetic field values ​​of the spatial point on the plane and the plane positioning result (x0, 0, z0):

[0117]

[0118] In order to ensure the uniqueness of the positioning result, the solution space is limited to the 1 / 4 spherical area (x<0, z>0), which can avoid multiple solutions and wrong solutions caused by the symmetry of the permanent magnet magnetic field. max Appears at the two major axes of the ellipse, and the θ corresponding to the maximum value obtained by solving the ellipse fitting function max The solution space constraint should also be met: if Take B max =-B max ,θ max =θ max -180°;

[0119] According to the peak field alignment characteristics, θ max The actual position section angle is marked. The above solution assumes that the position section is the XZ plane (θ max =90°), the angle difference between the actual plane and the assumed plane is Δθ = θ according to the magnetic field and the rotation angle of the corresponding external magnetic field generating device. max -90°, the plane positioning result (x0,0,z0) is converted to the actual position P:

[0120] P=[x,y,z]=rotx(Δθ)[x0;0;z0].

[0121] S700 , solving the posture matrix of the robot at the plane position according to the relationship between the model ellipse data and the sampled ellipse data, and then rotating it to the posture at the actual section point.

[0122] The posture of the robot in the tool coordinate system is represented by the matrix R, which satisfies the following equation from the model ellipse data to the sampled ellipse data:

[0123] R·b=B

[0124] Where R is the posture matrix of the robot in the tool coordinate system;

[0125] In reality, due to factors such as modeling errors and sensor noise, the equation is not strict. This embodiment uses the residual sum of squares (RSS) function to solve the attitude matrix R:

[0126]

[0127] Among them, (x, y, z) is the actual position solution in the previous step;

[0128] The robot posture is a 3×3 orthogonal matrix. The residual sum of squares (RSS) function is used to solve the posture matrix R. In the equation on the left side, at least two sets of vectors are needed to complete the solution of R. The vector data that constitutes the ellipse does not necessarily need to be used. Take two sets of eigenvectors of the sampling ellipse, the major axis B max , and the rotation axis N. The rotation axis vector N obtained from a large amount of ellipse vector data is compared with the minor axis B min The accuracy is higher, and the direction of the rotation axis satisfies the cross product rule (N=B(i)×B(i+1)), which is easier to judge.

[0129] At this time, the solution of the robot posture matrix using the residual square sum function is converted into the solution of the unit eigenvector transformation matrix corresponding to the ellipse:

[0130]

[0131] in, are the model vector ellipse major axis and rotation axis unit vectors;

[0132] In addition to the peak field alignment property, the vector ellipse also satisfies the mapping property: the magnetic field generated by the rotation of the external magnetic field generator has the same shape as the ellipse in the direction of rotation, and the ellipse at a single cross-section point is mapped to the ellipse distribution at any position. Based on this property, similar to the solution process for the above position, it is also possible to first assume that the robot is in the XZ plane to simplify the difficulty of solving the posture matrix. In this case, the ellipse eigenvector at the plane (x0,0,z0) satisfies:

[0133] a=[3x0z0;0;2z0 2 -x0 2 ],n=[x0 2 -2z0 2 ;0;3x0z0]

[0134] Substitute the transformation matrix of the unit eigenvector corresponding to the ellipse into the solution equation to obtain the posture matrix R0 at the robot's plane position, and then rotate it to the posture R at the actual section point (x, y, z). Generally, for ease of expression, the robot posture is expressed as the corresponding Euler angle (α, β, γ):

[0135]

[0136] At this point, the robot's 6-DOF magnetic positioning (x, y, z, α, β, γ) is solved.

[0137] This invention eliminates interference from magnetic components by embedding a sensor module within the magnetic catheter. Furthermore, a positioning algorithm based on magnetic field elliptical characteristics, tailored to the catheter's rotational drive conditions, is designed to provide 6-DOF magnetic field positioning information for the catheter. This approach has applications in a wide range of applications, including IVUS and OCT catheters, and is particularly well-suited for non-contact, visually constrained catheter tracking, addressing the potential need for closed-loop control of magnetic imaging catheters.

[0138] Example 4

[0139] A computer device 600, such as Figure 5 As shown, the system includes a memory 610, a processor 620, and a computer program 630 stored in the memory and executable on the processor. When the processor executes the computer program, the steps of a six-degree-of-freedom positioning method for an interventional imaging catheter are implemented. For a detailed description of the method, please refer to the corresponding description in the above method embodiment and will not be repeated here.

[0140] Example 5

[0141] A computer-readable storage medium such as Figure 6 As shown, a computer program is stored thereon, and when the computer program is executed by the processor, the steps of a six-degree-of-freedom positioning method for an interventional imaging catheter are implemented. For a detailed description of the method, reference can be made to the corresponding description in the above method embodiment, and no further details will be given here.

[0142] The number of devices and processing scales described herein are intended to simplify the description of the present invention. Applications, modifications, and variations of the present invention will be readily apparent to those skilled in the art.

[0143] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

[0144] The apparatus, computer device, non-volatile computer storage medium, and method provided in the embodiments of this specification correspond to each other. Therefore, the apparatus, computer device, and non-volatile computer storage medium also have similar beneficial technical effects as the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the corresponding apparatus, computer device, and non-volatile computer storage medium will not be repeated here.

[0145] Those skilled in the art will also appreciate that, in addition to implementing the controller in pure computer-readable program code, it is entirely possible to implement the same functionality by programming the method steps logically, such as through logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be considered structures within the hardware component. Alternatively, the devices for implementing various functions can be considered both software units implementing the method and structures within the hardware component.

[0146] The systems, devices, or units described in the above embodiments can be implemented by computer chips or physical devices, or by products with certain functions. For ease of description, the above devices are described separately by function, with each unit described separately. Of course, when implementing one or more embodiments of this specification, the functions of each unit can be implemented in the same or multiple software and / or hardware components.

[0147] Those skilled in the art will appreciate that the embodiments of this specification may be provided as methods, systems, or computer program products. Therefore, the embodiments of this specification may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the embodiments of this specification may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0148] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of this specification. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0149] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0150] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0151] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0152] This specification may be described in the general context of computer-executable instructions executed by a computer, such as program units. Generally, program units include routines, programs, objects, components, data structures, and the like that perform specific tasks or implement specific abstract data types. The specification may also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communications network. In a distributed computing environment, program units may be located in local and remote computer storage media, including storage devices.

[0153] The various embodiments in this specification are described in a progressive manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiments are generally similar to the method embodiments, so the description is relatively simple. For relevant parts, refer to the description of the method embodiments.

[0154] The foregoing is merely an example of the present invention and is not intended to limit the present invention to one or more embodiments. It will be apparent to those skilled in the art that various modifications and variations may be made to the present invention to one or more embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention to one or more embodiments shall be included within the scope of the claims of the present invention to one or more embodiments.

Claims

1. A six-degree-of-freedom positioning method for an interventional imaging catheter, characterized in that: The interventional imaging catheter includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The method includes the following steps: Controlling the external magnetic field generating device to rotate around the rotating shaft to generate a driving magnetic field, wherein the magnetic rotor component is acted upon by magnetic force and torque in the magnetic field, thereby driving the reflector to rotate to achieve axial scanning of the beam, thereby achieving catheter imaging; During the driving process, the composite magnetic field information of the external magnetic field generating device and the magnetic rotor component detected by the Hall magnetic field sensor array is obtained; Processing the sampled data of the Hall magnetic field sensor array to obtain a sampled magnetic field of the external magnetic field generating device after removing interference; Calculate the spatial magnetic field at any position of the interventional imaging catheter and obtain a rotating field model; Processing the sampled magnetic field of the external magnetic field generating device to obtain the required eigenvector and corresponding driving angle; The rotating field model is used to obtain the relationship between the maximum and minimum values ​​of the magnetic field of a spatial point on the plane and the plane positioning result, and the plane positioning result is converted to the actual position; The posture matrix at the robot's plane position is solved based on the relationship between the model ellipse data and the sampled ellipse data, and then it is rotated to the posture at the actual section point.

2. The six-degree-of-freedom positioning method for an interventional imaging catheter according to claim 1, wherein: The step of processing the sampled data of the Hall magnetic field sensor array to obtain the external magnetic field generating device driving magnetic field sampling after removing interference includes: Performing difference processing on the sampled data to obtain the magnetic vector of the magnetic rotor component in the plane; B subtract =B sensor1 -B sensor2 Among them, B sensor1 is the sampling data of the first Hall magnetic field sensor, B sensor2 is the sampling data of the second Hall magnetic field sensor; According to the 2D angle perception of the magnetic rotor component by the Hall magnetic field sensor array, the encoding angle of the magnetic rotor component in the YZ plane of the Hall magnetic field sensor array is: ϕ=tan -1 (−b z ,-b y ) Among them, b z , b y B subtract Vector components in the YZ plane; Select the composite magnetic field B sampled by the second Hall magnetic field sensor far away from the magnetic rotor component sensor2 , the rotating magnetic vector of the magnetic rotor component in the plane of the Hall magnetic field sensor array is separated according to the following formula to obtain the driving field sampling of the external magnetic field generating device after removing the interference: B=B sensor2 +k[0;cosφ;sinφ] Wherein, k is the magnetic field amplitude of the magnetic rotor component at the second Hall magnetic field sensor.

3. The six-degree-of-freedom positioning method for an interventional imaging catheter according to claim 2, wherein: The rotating field model is: Where μ0 is the vacuum magnetic permeability, (x, y, z) is the position on the interventional imaging catheter, θ is the motor angle, and M is the magnetic moment of the external magnetic field generating device.

4. The six-degree-of-freedom positioning method for an interventional imaging catheter according to claim 3, wherein: The step of processing the sampled magnetic field of the external magnetic field generating device to obtain the required characteristic vector and the corresponding driving angle includes: The rotation axis vector of the ellipse sensor is obtained by using singular value decomposition to sample the magnetic field of the external magnetic field generating device: N=SVD(B(1),B(2),···,B(n)) Among them, B(1), B(2), ···, B(n) are the sampling magnetic fields of the external magnetic field generating device; Perform a Rodriguez transformation on the rotation axis vector to obtain the transformation matrix to transform the three-dimensional ellipse to the XY plane to simplify subsequent operations: R transform =Rodrigues(N,[0;0;1]) Among them, R transform is the transformation matrix; In the ellipse fitting function, the transformation matrix transforms the 3D sample data B into 2D data, and the inverse matrix (R transform ) T Restore and finally get the required eigenvector and corresponding driving angle: the major and minor axis vectors B of the elliptical sensor max , B min and the motor angle θ at the corresponding sampling moment max ,θ min , the ellipse fitting function is: [B max ,θ max ,B min ,θ min ]=ellipsefitting(B,R transform ,θ) Wherein, θ=[θ(2),θ(2),...,θ(n)] is the motor rotation angle at the time corresponding to the sampling magnetic field.

5. The six-degree-of-freedom positioning method for an interventional imaging catheter according to claim 4, wherein: The step of obtaining the relationship between the maximum and minimum values ​​of the magnetic field of a spatial point on the plane and the plane positioning result by using the rotating field model, and converting the plane positioning result to the actual position includes: Assuming that the robot is located in the XZ plane, the rotation field model is used to obtain the relationship between the maximum and minimum values ​​of the magnetic field at a spatial point on the plane and the plane positioning result (x0,0,z0): Limit the solution space to the 1 / 4 sphere area, and the actual sensor sampling B max Appears at the two major axes of the ellipse, and the θ corresponding to the maximum value obtained by solving the ellipse fitting function max The solution space constraint should also be met: if Take B max =-B max , B max =θ max -180°; Assuming the position section is the XZ plane, according to the magnetic field and the rotation angle of the corresponding external magnetic field generating device, the angle difference between the actual plane and the assumed plane is △θ = θ max -90°, the plane positioning result (x0,0,z0) is converted to the actual position P: P=[x,y,z]=rotx(Δθ)[x0;0;z0].

6. The six-degree-of-freedom positioning method for an interventional imaging catheter according to claim 5, wherein: The step of solving the posture matrix at the robot's plane position according to the relationship between the model ellipse data and the sampled ellipse data, and then rotating it to the posture at the actual section point includes: From the model ellipse data to the sampling ellipse data, the following conditions are satisfied: R·b=B Where R is the posture matrix of the robot in the tool coordinate system; The residual square sum function is used to solve the attitude matrix: Among them, (x, y, z) is the actual position solution; The solution of the robot posture matrix is ​​converted into the solution of the unit eigenvector transformation matrix corresponding to the ellipse using the residual square sum function: in, are the model vector ellipse major axis and rotation axis unit vectors; Assume that the robot is in the XZ plane to simplify the difficulty of solving the posture matrix. At this time, the ellipse eigenvector at the plane (x0,0,z0) satisfies: a=[3x0z0;0;2z0 2 -x0 2 ],n=[x0 2 -2z0 2 ;0;3x0z0] Substitute the equation for the unit eigenvector transformation matrix corresponding to the ellipse to solve the posture matrix R0 at the robot's plane position, then rotate it to the posture R at the actual section point (x, y, z), and express the robot posture as the corresponding Euler angle (α, β, γ):

7. An interventional imaging catheter, using the method according to any one of claims 1 to 6, characterized in that: It includes a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The magnetic rotor component is used to drive the reflector and the external magnetic field generating device to move synchronously, and the Hall magnetic field sensor array is used to collect the three-axis magnetic field in space in real time.

8. An interventional imaging system, applying the method according to any one of claims 1 to 6, characterized in that: The invention comprises an interventional imaging catheter and an external magnetic field generating device. The interventional imaging catheter comprises a magnetic rotor component, a reflector, and a Hall magnetic field sensor array. The external magnetic field generating device serves as a system magnetic source to generate a driving magnetic field for the interventional imaging catheter, and the positioning range is highly consistent with the spatial location of the external magnetic field generating device. The extracorporeal magnetic field generating device rotates around a rotating axis to generate a driving magnetic field. The magnetic rotor component in the interventional imaging catheter is acted upon by magnetic force and torque in the magnetic field, driving the reflector to rotate to achieve axial scanning of the beam, thereby achieving catheter imaging. During the driving process, the Hall magnetic field sensor array detects the composite magnetic field information of the extracorporeal magnetic field generating device and the magnetic rotor component.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

Images