Permanent magnet navigation system

Abstract

The present invention discloses a permanent magnet navigation system, comprising: a magnetic field generating and controlling device, comprising a permanent magnet and a permanent magnet control component arranged vertically up and down; a generating device supporting component, comprising a supporting curved arm, a supporting curved arm lifting device and a base, wherein the permanent magnet is connected to both ends of the supporting curved arm, and the supporting curved arm is connected to the base. The present invention greatly reduces the weight and volume of the navigation permanent magnet through vertical magnet layout, adaptive pulse electric field ablation, upper magnet position optimization design, CNC motor drive simplification, catheter micromagnet optimization, etc., reduces the number and power of driving motors required to operate the permanent magnet, and improves navigation accuracy and efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a permanent magnet navigation system. Background Art

[0002] The existing cardiac interventional magnetic navigation system equipment usually adopts permanent magnet navigation or electromagnetic navigation;

[0003] Permanent magnet navigation system, such as the navigation device Genesis RMN of Stereotaxis in the United States, has the following basic implementation scheme: 1. Two mushroom-shaped combined permanent magnets are placed on both sides of the patient's chest to construct a navigation magnetic field, with the center point of the magnet aligned with the midpoint of the patient's heart. 2. The front and back positions of the patient's chest are reserved for the placement of the image intensifier (front chest) and X-ray tube generator (back) of the digital angiography device. 3. A single magnet is operated by a CNC motor group to achieve three-dimensional movement in five directions: up and down, front and back, left and right, left and right diagonal, and rotation. 4. The coordinated operation of the two magnets obeys the parallelogram law of the navigation magnetic field.

[0004] Its defects are as follows: 1. Since the front and back space of the patient's chest is occupied by the digital subtraction device, the navigation magnet can only be located on both sides of the patient's chest, which increases the distance between the navigation magnet and the surgical heart chamber, and is affected by the width of the patient's arms and the catheter treatment bed on both sides of the chest, resulting in a further increase in the distance between the magnet and the surgical heart chamber. Furthermore, since this magnetic navigation device is mainly designed for catheter treatment technology using radiofrequency ablation energy, in addition to the navigation needs to change the direction of the catheter, the navigation magnetic field also needs to increase a certain field strength to improve the contact force and contact quality between the catheter and the endocardium, so as to ensure the short-term and long-term effects of ablation treatment. Due to the above reasons, the weight and volume of the navigation magnet are inevitably increased. 2. The increase in the weight of the navigation magnet affects the navigation speed, accuracy, and efficiency on the one hand, and significantly increases the power and number of the drive motor on the other hand. At the same time, it also increases the floor load-bearing requirements for the construction and use of the catheter room, and increases the equipment noise. 3. The horizontal floor-standing layout of the navigation magnet occupies the best surgical position and space, affecting the surgical and emergency operations of medical staff. 4. The increase in magnetic field strength leads to greater interference of the permanent magnetic field on the catheter room environment, which increases the difficulty of magnetic protection and magnetic shielding of catheter room related equipment. 5. Due to the use of a dynamically changing composite magnetic field navigation mode, the motion control of the navigation magnet needs to overcome three major difficulties: First, the spatial operation direction and angle of a single magnet are required to be high, and multiple drive motors must be set up to meet the needs. Second, the coordinated control of the two magnets requires different complex algorithms, which increases the complexity of related control hardware and software. Third, it is necessary to dynamically measure the comprehensive field strength and direction of the composite magnetic field in order to drive the change of the actual composite magnetic field through the size and direction instructions of the target field strength to meet the navigation requirements. The result is a significant increase in the complexity of field strength control and navigation software.

[0005] Electromagnetic navigation systems, such as the navigation system of the Institute of Mechanical Engineering of the Chinese Academy of Sciences and the navigation system of Shaoxing Mayo Cardiomagnetic Medical Technology Co., Ltd., require a sufficient number of electromagnetic coils to generate a strong enough electromagnetic field to completely cover the surgical heart chamber. In addition, due to the special nature of the electromagnetic coils, auxiliary devices such as cooling devices are also required to cooperate with the electromagnetic coils. Therefore, the navigation magnet as a whole still has a large weight and volume, and has high requirements on the strength and power of its support and drive devices. Otherwise, it will significantly affect the navigation accuracy, efficiency and safety. Summary of the invention

[0006] The purpose of the present invention is to provide a permanent magnet navigation system, which solves the problems of the existing navigation system that the navigation magnet is heavy, large in size, and the navigation accuracy and efficiency need to be improved.

[0007] One aspect of the present invention provides a permanent magnetic navigation system, comprising:

[0008] A magnetic field generating and controlling device, including permanent magnets and permanent magnet control components arranged vertically up and down;

[0009] The generating device supporting component comprises a supporting curved arm, a supporting curved arm lifting device and a base, wherein the permanent magnet is connected to both ends of the supporting curved arm, and the supporting curved arm is connected to the base.

[0010] In the permanent magnet navigation system described above, the permanent magnet includes an upper permanent magnet and a lower permanent magnet, and the weight of the upper permanent magnet and the lower permanent magnet is less than 300 kg. Preferably, the permanent magnet is a cylinder; more preferably, the permanent magnet has a diameter of less than 80 cm and a height of less than 30 cm. More preferably, the permanent magnet is made of neodymium iron boron strong magnetic material, and the magnetic field strength is less than 500 gauss.

[0011] The permanent magnet navigation system described above, wherein when the system is used together with a catheter pulsed electric field ablation device, the weight of the upper permanent magnet and the lower permanent magnet are both less than 200 kg.

[0012] In the permanent magnet navigation system described above, the axial working distance of the upper permanent magnet is smaller than the axial working distance of the lower permanent magnet. The axial working distance of the upper permanent magnet is the distance between the upper permanent magnet and the origin before the navigation system starts working, and the axial working distance of the lower permanent magnet is the distance between the lower permanent magnet and the origin before the navigation system starts working, and the origin is the midpoint of the patient's heart. Preferably, the axial working distance of the upper permanent magnet is 11 cm, and the axial working distance of the lower permanent magnet is 17 cm.

[0013] In the permanent magnet navigation system described above, the weight of the upper permanent magnet is less than that of the lower permanent magnet, and the weight of the upper permanent magnet is less than 100 kg.

[0014] The permanent magnet navigation system described above, wherein the permanent magnet control component includes two groups of X-axis drive motors, Y-axis drive motors, and Z-axis drive motors arranged vertically up and down, and sliding support components corresponding to each drive motor. Preferably, the sliding support component includes a support arm and a moving component; more preferably, the top of the moving component is movably fixed to the top of the support arm, and its bottom is used to fix and suspend the support arm of the magnet or other axis. More preferably, the distribution of the moving components and support arms of the X, Y, and Z axes of the upper permanent magnet is: the Y axis is at the top, the X axis is in the middle, and the Z axis is at the bottom. The distribution of the lower permanent magnet is opposite to the above.

[0015] In the permanent magnet navigation system described above, the sliding support component includes a support arm and a moving component, and each driving motor is connected to the moving component to drive the moving component to move on the support arm.

[0016] In the permanent magnetic navigation system described above, the supporting crank arm is a C-shaped crank arm, and a supporting crank arm lifting device is provided in the middle part of the supporting crank arm. The supporting crank arm lifting device divides the supporting crank arm into an upper supporting crank arm and a lower supporting crank arm, and the supporting crank arm lifting device is driven by a crank arm lifting motor.

[0017] In the permanent magnet navigation system described above, the base includes a built-in navigation host, a power supply, a base lifting device, a base moving motor and a base guiding device. The built-in navigation host is electrically connected to the X-axis drive motor, the Y-axis drive motor, the Z-axis drive motor, the crank arm lifting motor, the base lifting motor, the base moving motor and the base guiding device, and the base drive motor is connected to the base guiding device.

[0018] In the above-mentioned permanent magnet navigation system, the base guide device includes a steering wheel and a driving wheel. Preferably, the steering wheel and the driving wheel are both provided with a brake device.

[0019] The permanent magnetic navigation system described above, wherein the permanent magnetic navigation system uses a composite magnetic field midpoint navigation method to guide the catheter to move and position, and performs navigation according to the following process:

[0020] (1) Constructing a three-dimensional navigation coordinate system for the surgical cardiac cavity;

[0021] (2) Preset surgical cardiac chamber spherical navigation points;

[0022] (3) Establish a general calculation formula for navigation point coordinate parameters;

[0023] (4) Establish a general calculation formula for two-point navigation parameters;

[0024] (5) Guide the flexible catheter to complete the navigation task according to the navigation instructions.

[0025] Beneficial Effects

[0026] The permanent magnetic navigation system of the present invention realizes the lightness of the permanent magnetic navigation system through technical innovations in four aspects:

[0027] 1. Comprehensive weight reduction technology for navigation magnets. (1) Weight reduction by navigation magnet layout. (2) Weight reduction by navigation magnetic field adaptation. (3) Weight reduction by navigation magnetic field optimization. (4) Weight reduction by CNC motor drive simplification. (5) Weight reduction by catheter micromagnet optimization.

[0028] 2. Navigation magnetic field optimization technology. (1) Individualized setting of the axial working distance between the upper and lower magnets. 2. Asymmetrical setting of the working distance between the upper and lower magnets and the working heart chamber.

[0029] 3. Navigation coordinate simplification technology. (1) Construct a three-dimensional navigation coordinate system for the surgical heart chamber. (2) Preset the spherical navigation points for the surgical heart chamber. (3) Establish a general calculation formula for navigation point coordinate parameters. (4) Establish a general calculation formula for two-point navigation parameters. (5) Composite magnetic field midpoint navigation technology.

[0030] 4. Magnet drive optimization technology. Due to the simplification of the three-dimensional coordinate system and navigation mode, the power, number and drive mode of the navigation magnet CNC motor have been significantly optimized: (1) The maximum power of the motor has been reduced from 500 watts to 150 watts, a decrease of 70%. (2) The number of motors has been reduced from 6 to 3, a decrease of 50%.

[0031] (3) The driving mode is simple and fast. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the structure of the permanent magnet navigation system of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the permanent magnet and the permanent magnet control component of the present invention;

[0034] Figure 3 It is a schematic diagram of the vertical coaxial layout of the permanent magnet and the permanent magnet control component structure of the present invention;

[0035] Figure 4 The figure is a schematic diagram of the body surface projection point of the center point of the heart on the anterior chest wall determined by the present invention.

[0036] The reference numerals are as follows:

[0037] Upper permanent magnet cover 1, upper supporting curved arm 2, supporting curved arm lifting device 3, lower supporting curved arm 4, base 5, base operation panel 6, driving wheel 7, steering wheel 8, lower permanent magnet cover 9, treatment bed 10, patient chest cavity 11, patient's in vivo heart 12, Y-axis sliding support component 101, Y-axis driving motor 102, X-axis driving motor 103, X-axis sliding support component 104, Z-axis sliding support component 105, Z-axis driving motor 106, upper permanent magnet 107, lower permanent magnet 108, front of patient's chest 201, sternal angle 202, sternal manubrium 203, xiphoid process 204, strongest pulsation point at the apex 205, projection of the center point of the patient's heart on the surface of the anterior chest wall 206, and the second intercostal space at the left edge of the sternum 207. DETAILED DESCRIPTION

[0038] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0039] 1. Structure and operation of permanent magnet navigation system

[0040] See also Figures 1 to 4 As shown, this embodiment provides a permanent magnet navigation system, including a magnetic field generating and controlling device, including two groups of permanent magnets arranged vertically up and down and a permanent magnet control component; a generating device supporting component, including a supporting crank arm, a supporting crank arm lifting device 3 and a base 5, the two groups of permanent magnets are connected to both ends of the supporting crank arm, and the supporting crank arm is connected to the base 5. Among them, the permanent magnet includes an upper permanent magnet 107 and a lower permanent magnet 108.

[0041] The upper permanent magnet 107 is cylindrical, with a diameter of less than 80cm, a height of less than 30cm, and a weight of less than 120kg. It adopts NdFeB strong magnetic material, and the magnetic field strength is less than 500 Gauss. It is located in the upper permanent magnet cover 1 together with the moving parts. The upper permanent magnet cover 1 is an elongated cylinder, and the long axis is parallel to the treatment bed. The upper permanent magnet cover 1 reserves a movement space of 20×30×20cm (X axis, Y axis, Z axis) for the upper permanent magnet 107. The upper permanent magnet cover 1 is located at the top of the upper part of the support crank arm and is connected to the support crank arm. The upper permanent magnet control component includes an X-axis drive motor 103, a Y-axis drive motor 102, a Z-axis drive motor 106, and a sliding support component corresponding to each drive motor. The sliding support component includes a support arm and a moving part. The drive motor of each axis is connected to the moving part of the corresponding axis to drive the moving part of each axis to move. Specifically, the driving motor can be a stepper motor, preferably a numerically controlled stepper motor, the support arm is a slide rail, the moving part is a slider, the stepper motor is connected to the built-in navigation host by electrical signals, and the movement is controlled by the built-in navigation host; the distribution of the moving parts and the supporting arm of the three orthogonal axes X, Y, and Z of the upper permanent magnet 107 is: the Y axis is at the top, the X axis is in the middle, and the Z axis is at the bottom. The three driving motors of the X, Y, and Z axes are numerically controlled driving motors. Under the drive of the navigation instruction, they run at the same time, different speeds and directions, and different three-dimensional coordinate distances, which can drive the upper permanent magnet 107 to move and position freely in three-dimensional space, and realize the free navigation of the midpoint of the navigation magnetic field on the spherical surface of the surgical heart chamber. The magnetic field surface of the upper permanent magnet 107 points downward to the patient's anterior chest wall, and the midpoint of the magnetic field surface points to the body surface projection point of the patient's heart midpoint on the anterior chest wall. The magnetic field surface is provided with a receiver, which can sense the positioning electrode attached to the projection 206 of the patient's heart center point on the anterior chest wall surface to determine and adjust the initial position of the navigation magnetic field.

[0042] The lower permanent magnet 108 and the control component and the lower permanent magnet cover 9 are arranged in a mirror relationship with the upper permanent magnet 107, and the lower permanent magnet cover 9 is located at the top of the lower part of the supporting arm. The magnetic field surface points upward to the patient's posterior chest wall. The midpoint of the magnetic field surface points to the body surface projection point of the patient's heart midpoint on the posterior chest wall, is coaxial with the midpoint of the magnetic field surface of the upper permanent magnet 107, and synchronously sets and adjusts the initial position of the navigation magnetic field with the upper permanent magnet 107. The weight and volume of the lower permanent magnet 108 are greater than those of the upper permanent magnet 107, so the magnetic field range and intensity are also greater than those of the upper permanent magnet 107. The midpoint of the individualized navigation magnetic field formed by the upper and lower permanent magnets is biased to one side of the upper magnet. The relative position of the upper and lower magnets can be determined individually according to the spatial position of the patient's heart. Once determined, they will always maintain coaxial synchronous operation during the same operation. The lower permanent magnet 107 and the upper permanent magnet 108 together form a coaxial and copolar mirror image magnet pair, and an individualized composite navigation magnetic field is jointly constructed by individually adjusting the distance between the magnetic field planes of the two mirror image permanent magnets.

[0043] In this embodiment, the layout of the existing navigation magnets on both sides of the patient's chest is changed, and the navigation permanent magnets are redesigned to be arranged in the front and back directions of the patient's chest.

[0044] The basic principle and calculation method of navigation permanent magnet layout weight reduction: 1) The patient lies in a supine position, with the midpoint of the patient's heart as the calculation origin, and the average diameter of the patient's heart sphere is set to 8cm. 2) The horizontal transverse diameter of the patient's chest passing through the midpoint of the heart (from the side to the outside of the patient's upper arm) is an average of 60cm, and the vertical longitudinal diameter is an average of 30cm. 3) The horizontal transverse diameter and the vertical longitudinal diameter are asymmetrical, and the horizontal transverse diameter passing through the midpoint of the heart is 50% longer than the vertical longitudinal diameter. 4) Weight reduction effect of navigation permanent magnet layout: After changing the layout of the two permanent magnets from the two sides of the chest to the front and back of the chest, the navigation permanent magnet can be reduced by 50%, that is, from the current single navigation permanent magnet of 800kg to less than 300kg.

[0045] The permanent magnet navigation system of this embodiment is used together with the catheter pulse electric field ablation device. Compared with the catheter radiofrequency ablation in the prior art, its navigation purpose is only one, that is, to change the direction of the catheter tip, and there is no need to increase the contact force between the catheter tip and the endocardial tissue. Therefore, by adapting different catheter ablation techniques, the weight of a single navigation magnet can be significantly reduced. The basic principles and calculation methods of navigation magnetic field adaptation and weight reduction: 1) The effective tissue contact force range required by catheter radiofrequency ablation technology is 5 to 25g, with an average of 15g. 2) When catheter pulse ablation technology is used, only the catheter tip needs to contact or be very close to the endocardial tissue, and no additional tissue contact force is required. 3) Navigation magnet adaptation and weight reduction effect: When cardiac magnetic navigation is mainly aimed at adapting catheter pulse ablation technology, the working field strength of the navigation magnetic field can be reduced from the current average of 800 gauss to 400 gauss. Therefore, the weight of a single navigation magnet can be further reduced from 300kg to below 200kg.

[0046] This embodiment also fully considers that the human heart is located in the anterior mediastinum of the chest cavity, and the distance from the midpoint of the heart to the front chest surface is significantly different from the distance to the back surface. Therefore, the navigation working magnetic field adopts an asymmetric composite magnetic field design, which further reduces the weight of the upper permanent magnet 107 located at the front chest of the patient.

[0047] The basic principle and calculation method of navigation magnetic field optimization for weight loss: 1) The patient lies in a supine position, with the midpoint of the patient's heart as the calculation origin, and the average diameter of the patient's heart sphere is set to 8 cm. 2) The horizontal transverse diameter of the patient's chest through the midpoint of the heart (from the side to the outside of the patient's upper arm) is an average of 60 cm, and the vertical longitudinal diameter is an average of 30 cm. 3) The anterior and posterior longitudinal diameters are asymmetric. The posterior longitudinal diameter from the midpoint of the heart to the patient's back surface is 50% longer than the anterior longitudinal diameter to the front chest surface. 4) Navigation magnetic field optimizes weight loss effect: Based on the principle that the anterior longitudinal diameter is 50% shorter than the posterior longitudinal diameter, this embodiment designs an asymmetric composite magnetic field, which can further reduce the weight of the permanent magnet 107 located in the front chest by 50%, that is, from 200 kg to less than 100 kg.

[0048] Specific implementation plan for the asymmetric layout of upper and lower permanent magnets:

[0049] 1) The axial working distance of the upper and lower magnets is set asymmetrically

[0050] a. The distance between the center of the heart and the anterior and posterior chest surface. According to the spatial position of the heart in the chest cavity, the average anterior-posterior diameter of the normal adult heart is 6 cm. The average straight-line distance between the anterior wall of the heart and the anterior chest surface is 3 cm, and the average straight-line distance between the posterior wall of the heart and the dorsal surface is 6 cm. Based on this calculation, the average straight-line distance between the center of the heart and the anterior chest surface is 6 cm, and the average straight-line distance from the dorsal surface is 9 cm.

[0051] b. The reserved safety distance between the magnet surface and the patient's body surface: 2 cm above and below.

[0052] c. The average thickness of the treatment bed is 5cm.

[0053] d. Working stroke of the magnet moving up and down: calculated based on the anteroposterior diameter of the heart, an average of 6 cm.

[0054] e. Calculation of the axial working distance of the upper and lower permanent magnets. The center of the heart is taken as the working origin. Before the navigation system starts working, the starting position of the magnet is set relative to the origin. The distance between the upper permanent magnet 107 and the origin = half of the anterior-posterior diameter of the heart (3cm) + the distance from the anterior wall of the heart to the anterior chest surface (3cm) + the reserved safety distance (2cm) + the working stroke of half of the anterior-posterior diameter of the heart (3cm) = 11cm. The distance between the lower permanent magnet 108 and the origin = half of the anterior-posterior diameter of the heart (3cm) + the distance from the posterior wall of the heart to the posterior back surface (6cm) + the thickness of the treatment bed (3cm) + the reserved safety distance (2cm) + the working stroke of half of the anterior-posterior diameter of the heart (3cm) = 17cm. The axial working distance between the upper and lower magnets = 11cm + 17cm = 28cm.

[0055] 2) Individually define the magnet working distance based on the spatial positioning of the heart in vivo

[0056] a. Determine the projection point of the heart center on the anterior chest wall. Determine the projection point of the heart center on the anterior chest wall based on the bony landmarks on the body surface: (1) Determine the second intercostal space based on the sternal angle, and determine the upper right projection point of the heart 2 cm from the right edge of the sternum at this level; (2) Determine the lower left projection point of the heart based on the apex beat; (3) Connect the above two points to obtain the diagonal line of the heart projection; (4) The midpoint of this diagonal line is the projection point of the heart center on the anterior chest wall; (5) Paste an X-ray-detectable positioning patch at this point for later use.

[0057] b. Determine the projection point of the heart center on the left chest wall. The height from the treatment bed. (1) Use a movable angle ruler to measure the vertical distance between the patient's chest surface and the treatment bed surface at the most obvious apex beat; (2) Subtract 6 cm from this distance to get the height of the heart center from the treatment bed surface; (3) Paste an X-ray-transmissive detectable patch at the above height on the patient's left chest wall for later use.

[0058] c..Calibration of the magnet's starting working position. (1) The electrode detector located on the surface of the upper permanent magnet 107 automatically completes the horizontal position calibration of the starting working point; (2) The electrode detector located on the inner side of the supporting arm automatically completes the vertical position calibration of the starting working point.

[0059] 3) Weight reduction effect of asymmetric layout of upper and lower permanent magnets

[0060] Relative to the heart origin, the working distance of the lower permanent magnet 108 is (28-17) / 28=39.3% farther than that of the upper permanent magnet 107. Therefore, to keep the upper and lower permanent magnets with the same field strength at the working origin, the lower permanent magnet 108 needs to be 40% larger than the upper permanent magnet 107.

[0061] The support arm is a C-shaped arm, the notch of the C points to the left side of the treatment bed, the upper end is connected to the upper permanent magnet 107 Y-axis sliding support component 105, the lower end is connected to the lower permanent magnet 108 Y-axis sliding support component, and the bottom is connected to the lifting base 5. A support arm lifting device 3 is provided in the middle of the support arm to separate the support arm into an upper support arm 2 and a lower support arm 4. The support arm lifting device 3 consists of a crank arm lifting shaft and a crank arm lifting motor, and the crank arm lifting motor drives the crank arm lifting shaft to move up and down, which is used to adjust the working height of the upper permanent magnet 107 individually.

[0062] The base 5 includes a built-in navigation host, a power supply, a base lifting device, a base moving motor and a base guiding device. The base lifting device includes a base lifting shaft and a base lifting motor, which is located in the middle of the base and is used to adjust the height of the supporting curved arm, cooperate with the lifting function of the treatment bed, and finely coordinate the initial position of the navigation magnetic field and the working height of the lower permanent magnet 108. The built-in navigation host is connected to the X-axis drive motor 103, the Y-axis drive motor 102, the Z-axis drive motor 106, the curved arm lifting motor, the base lifting motor, the base moving motor, and the base guiding device by electrical signals, and the base moving motor is connected to the base guiding device. The base 5 is provided with an operation panel for operating the built-in navigation host from the outside and controlling the operation of the equipment connected thereto.

[0063] The base guiding device includes a steering wheel 8 and a driving wheel 7. The base moving motor drives the driving wheel 7 to rotate. Both the steering wheel 8 and the driving wheel 7 are provided with a braking device for fixing the magnetic navigation system at the working position or the storage position.

[0064] In order to achieve free positioning navigation of a flexible catheter guided by a composite navigation magnetic field on the spherical surface of a surgical cardiac cavity, this embodiment proposes a composite magnetic field midpoint navigation technology, the purpose of which is to use a simplified three-dimensional coordinate system and its calculation formula to perform navigation according to the following process:

[0065] (1) Constructing a three-dimensional navigation coordinate system for the surgical cardiac cavity;

[0066] ① Determine the coordinate orientation. Set the coordinate orientation according to the frontal plane, sagittal plane, and cross-section of human anatomy. The X-axis and Y-axis are located in the frontal plane, with the X-axis being positive on the left side of the patient and negative on the right side; the Y-axis being positive on the patient's head and negative on the foot. The X-axis and Z-axis are located in the cross-section, with the Z-axis being positive on the patient's chest and negative on the back. The Y-axis and Z-axis are located in the sagittal plane, with the positive and negative directions being the same as above. Based on the above coordinate orientation, the three-dimensional image of the patient's surgical heart cavity is stereoscopically positioned to construct a three-dimensional navigation coordinate system.

[0067] ② Determine the origin of the coordinates. That is, the center point of the surgical heart chamber. Determination method: 1) On the surgical heart chamber that has completed stereo positioning, measure the maximum inner diameters of the X, Y, and Z axes respectively; 2) Compare and select the maximum inner diameter of the three as the first inner diameter passing through the origin; 3) Compare and select the maximum inner diameter of the remaining two as the first plane perpendicular to the inner diameter of the origin; 4) Re-obtain the maximum inner diameter of the axis that intersects with the first maximum inner diameter on this plane; 5) The intersection of the above two maximum inner diameters is the center point of the surgical heart chamber, which is also the origin of the coordinates.

[0068] ③ Construct an individualized three-dimensional coordinate system. Draw the third inner diameter line vertically from the above coordinate origin and intersect the surgical heart chamber sphere to form a complete individualized three-dimensional navigation coordinate system. The navigation coordinate system can be pre-constructed on the simulated surgical heart chamber three-dimensional image with system default and actual parameter revision, or it can be pre-constructed on the actual surgical heart chamber three-dimensional image to be fused.

[0069] (2) Preset surgical cardiac chamber spherical navigation points;

[0070] On the surgical heart chamber sphere with three-dimensional coordinates already constructed, spherical coordinate navigation points are constructed with a resolution of square millimeters, and the navigation points are computer-encoded. These navigation points are mainly used for the following three purposes: ① Navigation initial start point. When the system first identifies the magnetic catheter in the surgical heart chamber, the location of the catheter head will be automatically identified as the navigation initial start point. ② Navigation start point. When the catheter leaves the initial navigation point according to the operator's operating instructions and reaches the first navigation target point, the target point is defaulted to the first navigation starting point. ③ Navigation target point. It is selected by the operator's instructions and constitutes the navigation trajectory and navigation parameters with the previous navigation start point.

[0071] (3) Establish a general calculation formula for navigation point coordinate parameters;

[0072] ① Establish a general calculation formula for the basic coordinates of navigation points so that they can be used as navigation start points and navigation target points in the actual navigation process.

[0073] ② Establish the calculation formula of basic navigation parameters of navigation points, mainly including the projection distance and direction of the navigation in three-dimensional coordinates.

[0074] (4) Establish a general calculation formula for two-point navigation parameters;

[0075] ① Navigation point function conversion. All navigation points are divided into navigation initial start point (automatically identified by the system), navigation start point and navigation target point. Except for the navigation initial start point, other navigation points will be converted at any time according to different purposes. When the navigation between the two points specified by the instruction is completed, the navigation target point automatically becomes the start point of the next round of navigation action.

[0076] ② Calculate the navigation distance and direction parameters of the target point. The projection distance of the two points on each orthogonal coordinate axis of the three-dimensional coordinates, combined with the projection direction pointing to the navigation target point, is the navigation distance and direction instruction parameters of the target point.

[0077] ③ Calculate the target point navigation time parameters. The maximum navigation time between two points = the maximum projection distance of the two navigation points on the three orthogonal coordinate axes / the maximum speed of the CNC motor. The navigation time of other coordinates = the projection distance of each coordinate / the maximum speed of the CNC motor.

[0078] ④ Calculate the target point navigation speed parameter. That is, calculate the working speed of the CNC motor located on the three orthogonal coordinate axes. The calculation formula is: the working speed of the CNC motor = the projection distance of the two navigation points on their respective orthogonal coordinate axes / the maximum navigation time between the two points.

[0079] (5) Guide the flexible catheter to complete the navigation task according to the navigation instructions. The built-in navigation host drives the three CNC drive motors of the X, Y, and Z axes according to the operator's navigation instructions and the three-dimensional coordinate system and its calculation formula to guide the flexible catheter to complete the navigation task.

[0080] The asymmetric composite magnetic field midpoint navigation mode of this embodiment greatly reduces the number and power of drive motors and optimizes the operation mode, thereby further reducing the weight of the navigation magnet control components, saving energy consumption, and simplifying.

[0081] In terms of quantity, the existing cardiac magnetic navigation equipment drives the navigation magnet using 5 CNC motors responsible for 5 different directions of movement, including lifting, advancing and retreating, translation, tilting, and rotation. The different movement combinations between the two navigation magnets are controlled by a computer to generate changes in the direction of the composite magnetic field comprehensive vector, thereby achieving three-dimensional navigation of the direction of the catheter head end in the heart cavity. We call this navigation magnet control method a composite magnetic field vector navigation mode. According to the above content, this embodiment uses the principle of spherical stereoscopic navigation to synchronously operate two navigation magnets on the three-dimensional coordinate axes of X, Y, and Z, thereby controlling the working center point of the asymmetric composite magnetic field to move freely between any navigation points on the three-dimensional spherical surface of the surgical heart cavity, which can reduce the number of driving motors of the navigation magnet by nearly 50%, that is, the number of motors driving a single navigation magnet is reduced from 5 to 3, thereby further reducing the total weight of the navigation magnet.

[0082] In terms of power, the navigation magnet is significantly lighter, which will significantly reduce the power of the CNC motor that drives the magnet. According to calculations, when the weight of a single navigation magnet is reduced from 800kg to 200kg, the maximum power of the CNC motor can be reduced from the current 500 watts to 150 watts, a reduction of 70%.

[0083] The specific calculation process is as follows:

[0084] 1) Estimation of motor power required to drive 800kg navigation magnet:

[0085] F=mg,P=FV

[0086] P=800*9.8*2.5 / 60≈326.67W

[0087] Consider motor efficiency and drive train efficiency factors:

[0088] Need to use: 326.67*1.5≈500W motor.

[0089] 2) Estimation of the motor power required to drive a 200kg navigation magnet:

[0090] F=mg,P=FV

[0091] P=200*9.8*2.5 / 60≈81.67W

[0092] Consider motor efficiency and transmission system efficiency factors:

[0093] Need to use: 81.67*1.8≈150W motor.

[0094] 3) Motor power reduction after drive optimization:

[0095] (500-150) / 500=70%

[0096] In terms of CNC motor operation mode optimization,

[0097] (1) The built-in navigation host of this embodiment automatically identifies the initial navigation start point (i.e., the initial position of the tip of the flexible magnetic catheter in the cardiac cavity during surgery) according to the three-dimensional coordinate system and its calculation formula.

[0098] (2) The surgeon selects the navigation target point. After the navigation process is completed, this point automatically becomes the starting point for subsequent navigation, and so on.

[0099] (3) The surgeon issues navigation instructions.

[0100] (4) The built-in navigation host automatically retrieves and calculates the direction and absolute distance that the navigation magnetic field needs to move in three-dimensional coordinates.

[0101] (5) The built-in navigation host calculates the total navigation time based on the maximum operating speed of the drive motor and the maximum moving distance on the three-dimensional coordinate X, Y, and Z axes.

[0102] (6) Calculate the motor speeds of the other two axes based on the total navigation time.

[0103] (7) Based on the three-dimensional coordinate navigation parameters and the drive motor parameters, the drive motor group of the three-dimensional coordinate axis is synchronously started to drive the navigation magnet to change the navigation midpoint of the composite magnetic field to reach the navigation target point, thereby driving the flexible magnetic conduit to move accurately to the navigation target point.

[0104] (8) If the available length of the flexible magnetic conduit is shorter than the length required to reach the navigation target point, the conduit head will only change direction and cannot move to reach the navigation target point.

[0105] (9) When the operator manipulates the catheter driver to change the available length of the catheter in the body, the catheter tip will directly reach the navigation target point according to the positioning requirements of the navigation target point.

[0106] (10) The surgeon can optimize or adjust the catheter tip positioning quality by using the catheter electrophysiological parameters and the catheter three-dimensional posture.

[0107] Furthermore, this embodiment also improves the outer diameter of the electrophysiological ablation catheter. The specific principle is as follows:

[0108] Since the completion of cardiac magnetic navigation depends on the cooperation of the flexible magnetic catheter located in the surgical heart cavity, the main cooperation method is to set a micro-magnet group at the catheter head end, so that when the catheter head end enters the navigation magnetic field, due to the interaction between the catheter micro-magnet and the navigation magnetic field, the navigation magnet and its navigation magnetic field can drive the flexible catheter to complete three-dimensional positioning navigation.

[0109] Changing the shape, weight, volume and combination pattern of the catheter tip micromagnets can optimize the interaction and response speed between the catheter micromagnets and the navigation magnetic field. The basic rules are: (1) The larger the weight and volume of the catheter micromagnets, and the greater their number, the stronger their interaction with the navigation magnetic field, and the navigation magnets that drive the catheter to achieve navigation positioning can be made lighter and smaller. (2) While ensuring that the cardiac navigation conditions and effects remain unchanged, increasing the weight and number of catheter micromagnets can correspondingly reduce the intensity of the navigation magnetic field, thereby achieving the purpose of reducing the weight of the navigation magnets.

[0110] The weight of the catheter micromagnet is related to its length, but the more important factor is its outer diameter. The outer diameter of the catheter micromagnet is mainly controlled by the outer diameter of the catheter. The outer diameter of the catheter is mainly affected by the catheter access, surgical purpose, manufacturing materials and process.

[0111] The outer diameters of existing adult electrophysiology ablation catheters are mainly 7F and 8F, and their design ideas are mainly derived from the femoral vein and femoral artery access of traditional electrophysiology technology. In order to reduce peripheral arterial complications and reduce damage to the aortic valve, the ablation catheter used for the femoral artery retrograde route is usually designed to be 7F, while the ablation catheter used for the femoral vein route is designed to be 8F. The latter is mainly designed to improve maneuverability and mapping and ablation efficiency.

[0112] However, with the development of electrophysiological interventional technology, the treatment of left heart arrhythmias is increasingly being performed through atrial septal puncture, thus avoiding complications of femoral artery access and damage to the aortic valve due to retrograde transvalvular aortic valve. Because the femoral vein approach has the characteristics of large diameter, short path, straight shape, and antegrade blood flow, when it is necessary to increase the outer diameter of the catheter to achieve professional diagnosis and treatment purposes, the femoral vein approach is one of the ideal choices.

[0113] The outer diameter of the flexible cardiac magnetic catheter currently used in clinical practice is 8F.

[0114] In this embodiment, the outer diameter of the catheter is increased, for example, from 8F to 9, 10 or 11F (1F = 0.33mm). Even if the magnet length remains unchanged, the weight and volume of the catheter micromagnet can be significantly increased simply by increasing the outer diameter. The calculation method of the increase degree is as follows:

[0115] 1. When the outer diameter of the catheter increases by one F number (for example, from 8F to 9F), the weight increase percentage of the catheter micromagnet is: (9-8)*0.033 / 8*0.33*100%=12.5%.

[0116] 2. When the outer diameter of the catheter increases by one F number (for example, from 8 F to 9 F), the volume of the catheter micromagnet increases by a percentage of: (9*0.33 / 2*πh-8*0.33 / 2*πh)*100%=9*0.33 / 2*πh%, where h is the length of the catheter micromagnet.

[0117] 3. The increase in weight and volume of the catheter micromagnet can improve the responsiveness of the catheter micromagnet to the navigation magnetic field, thereby achieving the purpose of achieving the same navigation effect with a smaller navigation magnetic field and a lighter navigation magnet.

[0118] 4. As the outer diameter of the flexible magnetic catheter increases, the surface area of ​​the electrode at the catheter tip will also increase accordingly, thereby improving the efficiency of electrophysiological mapping and ablation.

[0119] 2. Working process of permanent magnet navigation system

[0120] 1. The patient lies flat on the treatment bed in the catheterization room, exposing the left anterior chest wall and lateral chest wall.

[0121] 2. Determine the second intercostal space based on the sternal angle, and mark the upper right point of the heart shadow 2 cm from the left edge of the sternum in this intercostal space; mark the lower left point of the heart shadow 1 cm below and outside the most obvious part of the apex beat; and paste a detectable positioning patch at the midpoint of the line connecting the above two points.

[0122] 3. Measure the thickness of the patient's chest wall at the point where the apex beat is most obvious. The value minus 6cm is the height of the center of the heart from the treatment bed.

[0123] 4. Paste all other electrophysiological body surface electrodes and make sure they are securely pasted.

[0124] 5. Perform routine surgical disinfection and draping to establish a sterile surgical environment.

[0125] 6. After local anesthesia, percutaneous vascular puncture is performed, the sheath and flexible magnetic catheter are inserted, and surgical conditions are established.

[0126] 7. Adjust the height of the treatment bed to reach the working height range of the permanent magnet navigation system.

[0127] 8. Remove the protective cover of the permanent magnet navigation system, turn on the power, and perform system self-check.

[0128] 9. Operate the operation panel to guide the permanent magnet navigation system to the left side of the treatment bed, so that the surface of the upper permanent magnet 107 is roughly aligned with the projection 206 of the patient's heart center on the anterior chest wall surface, and start the brakes of the driving wheel 7 and the steering wheel 8 at the bottom of the base 5 to fix the permanent magnet navigation system.

[0129] 10. The upper magnet electrode detector detects the detectable positioning patch on the patient's anterior chest wall, starts the automatic positioning function, and the permanent magnet navigation system automatically calibrates the magnet's starting working position.

[0130] 11. Start the navigation software, and the surgeon controls the magnet through the built-in navigation host to complete the three-dimensional cardiac navigation surgery.

[0131] 12. The operator clicks the target navigation point on the three-dimensional reconstructed image of the working heart cavity. The host calculates the three-dimensional navigation distance according to the X, Y, and Z axes, and then synchronously drives the motor groups of the upper and lower magnets according to the motor combination to guide the magnet navigation center point to move accurately to the position of the target navigation point, thereby driving the head end of the magnetic catheter to accurately point to the navigation point. With the cooperation of the patient's extracorporeal catheter advance and retreat drive, the catheter head end accurately contacts the endocardial tissue at the navigation point.

[0132] 13. This process is repeated in this way to complete all navigation operations for the surgery.

[0133] 14. After the operation is completed, the navigation software is closed and the brakes of the driving wheel 7 and the steering wheel 8 are retracted.

[0134] 15. Drive the robot to the storage position by operating the base operation panel 6.

[0135] 16. Start the brakes of the driving wheel 7 and the steering wheel 8 to prevent the robot from accidentally moving.

[0136] 17. Turn off the power and cover the protective cover.

[0137] In summary, the permanent magnet navigation system of the present invention has the following advantages:

[0138] 1. Since the weight and volume of the navigation magnet are greatly reduced, the navigation accuracy and efficiency are significantly improved, and the motor power is reduced.

[0139] 2. Transform the magnetic navigation equipment from fixed installation to free movement, effectively freeing up the space in the catheterization room.

[0140] 3. Enable navigation equipment to actively adapt to various existing catheter rooms, eliminating the need to specially build large magnetic navigation catheter rooms.

[0141] 4. Magnetic navigation is no longer bundled with DSA (Digital subtraction angiography) equipment, but becomes an independent device, greatly reducing the cost of the whole device.

[0142] 5. The two navigation magnets run synchronously in a coaxial manner without changing the relative distance, position and angle, which significantly reduces the number of drive motors required to run the magnets.

[0143] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A permanent magnet navigation system, characterized in that: include: A magnetic field generating and controlling device, including permanent magnets and permanent magnet control components arranged vertically up and down; The generator support component includes a support crank arm, a support crank arm lifting device and a base, wherein the permanent magnet is connected to both ends of the support crank arm, and the support crank arm is connected to the base; The permanent magnet comprises an upper permanent magnet and a lower permanent magnet; The permanent magnet control component includes two groups of X-axis drive motors, Y-axis drive motors, and Z-axis drive motors arranged vertically up and down, and sliding support components corresponding to each drive motor; The sliding support component includes a support arm and a moving component, and each driving motor is connected to the moving component to drive the moving component to move on the support arm; The weight and volume of the lower permanent magnet are greater than those of the upper permanent magnet, and the magnetic field range and strength of the lower permanent magnet are also greater than those of the upper permanent magnet; the midpoint of the individualized navigation magnetic field formed by the upper permanent magnet and the lower permanent magnet is biased toward one side of the upper permanent magnet; The relative positions of the upper permanent magnet and the lower permanent magnet are individually determined according to the spatial position of the patient's heart. Once determined, they will always maintain coaxial and synchronous operation during the same operation. The axial working distance of the upper permanent magnet is smaller than the axial working distance of the lower permanent magnet; the support crank arm lifting device is provided in the middle of the support crank arm, which separates the support crank arm into an upper support crank arm and a lower support crank arm, and the components of the support crank arm lifting device include a crank arm lifting shaft and a crank arm lifting motor, and the crank arm lifting motor drives the crank arm lifting shaft to move up and down, so as to adjust the working height of the upper permanent magnet; The permanent magnet navigation system is used together with a catheter pulse electric field ablation device.

2. The permanent magnetic navigation system according to claim 1, characterized in that: The weight of the upper permanent magnet and the lower permanent magnet is less than 300 kg.

3. The permanent magnetic navigation system according to claim 2, characterized in that: The weight of the upper permanent magnet and the lower permanent magnet is less than 200 kg.

4. The permanent magnetic navigation system according to claim 1, characterized in that: The weight of the upper permanent magnet is less than that of the lower permanent magnet, and the weight of the upper permanent magnet is less than 100 kg.

5. The permanent magnetic navigation system according to claim 1, characterized in that: The base includes a built-in navigation host, a power supply, a base lifting device, a base moving motor and a base guiding device. The built-in navigation host is electrically connected to the X-axis drive motor, the Y-axis drive motor, the Z-axis drive motor, the crank arm lifting motor, the base lifting motor, the base moving motor and the base guiding device. The base drive motor is connected to the base guiding device.

6. The permanent magnetic navigation system according to claim 1, characterized in that: The permanent magnetic navigation system uses a composite magnetic field midpoint navigation method to guide the catheter to move and position, and performs navigation according to the following process: (1) Constructing a three-dimensional navigation coordinate system for the surgical cardiac chamber; (2) Preset the spherical navigation point of the surgical heart chamber; (3) Establish a general calculation formula for navigation point coordinate parameters; (4) Establish a general calculation formula for two-point navigation parameters; (5) Guide the flexible catheter to complete the navigation task according to the navigation instructions.

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