Multi-degree-of-freedom mechanical system for magnetic resonance guided interventional therapy

Abstract

The invention relates to the technical field of medical equipment, in particular to a multi-degree-of-freedom mechanical system for magnetic resonance guided interventional therapy. The upper shear fork mechanism and the lower shear fork mechanism are mounted through the fixed base; the two groups of differential mechanisms are used for driving the upper shear fork mechanism and the lower shear fork mechanism respectively; the upper end of the joint rotating rod is connected with the working end of the upper shear fork mechanism through guide fit, and the lower end of the joint rotating rod is connected with the working end of the lower shear fork mechanism through ball joint fit; and the puncture mechanism is fixedly mounted at the upper end of the joint rotating rod. According to the technical scheme, the multi-degree-of-freedom mechanical system for magnetic resonance guided interventional therapy can be specially adapted to the MRI environment, multi-degree-of-freedom flexible control can be achieved, the mechanical system has the high-precision positioning capacity, the strict requirements of non-magnetic materials and miniaturization are met, the diagnosis and treatment requirements of multiple parts can be met, and the application prospect is wide. Safety and reliability are ensured in real treatment, and operation is easy and convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to a mechanical system with multiple degrees of freedom for magnetic resonance-guided interventional treatment. Background Art

[0002] In the modern medical field, magnetic resonance imaging (MRI) has become a key tool for clinical diagnosis and treatment due to its excellent soft tissue resolution and no ionizing radiation. Based on MRI's real-time imaging and high-precision positioning, magnetic resonance-guided intervention (MRI-Guided Intervention) has developed rapidly in recent years, with applications covering prostate tumor puncture biopsy and ablation, spinal vertebral puncture, breast biopsy, liver tumor ablation, bone and joint disease intervention and other fields. Compared with traditional interventional methods, MRI-guided treatment can be performed under clearer anatomical images and real-time monitoring, significantly improving the accuracy and safety of diagnosis and treatment.

[0003] Treatment in a strong magnetic field environment also requires the use of a mechanical system to achieve precise positioning and control of treatment devices (such as puncture devices, ultrasonic transducers, needles, catheters, etc.).

[0004] For example, a puncture robot system is disclosed in the Chinese invention patent application with publication number CN114983568A and titled “Laser-assisted positioning method and puncture robot system in interventional surgery”. Figure 1 , it includes a mobile device 210, a support arm 220, a laser pointing device 230, a mechanical arm 240 and a puncture device 250; the support arm 220 is arranged on the mobile device 210, the laser pointing device 230 is arranged on the support arm 220, and the laser pointing device 230 has at least two degrees of freedom. The mobile device 210 can be a cart, a mobile table, etc. The support arm 220 on the mobile device 210 supports the laser pointing device 230, and combined with the at least two degrees of freedom of the laser pointing device 230, the emitted laser can be laser-assisted positioned on the object (patient). The mechanical arm 240 is arranged on the mobile device 210, and the mechanical arm 240 has at least five degrees of freedom; the puncture device 250 is arranged on the mechanical arm 240, and a registration piece is arranged on the puncture device 250. The mechanical arm 240 with five degrees of freedom can make the puncture device 250 move in the coronal plane, sagittal plane and transverse plane, so as to complete the target action. The registration piece can be a Z-type registration piece to improve the registration efficiency. The puncture device 250 may also be provided with devices such as a puncture needle and a calibration tool.

[0005] However, the above technical solutions and other prior arts have the following problems:

[0006] (1) Because the mechanical structure contains magnetic materials or uses traditional metal motors, such as Figure 1 Laser pointers used in MRI often use magnetic materials as modulators, which results in insufficient magnetic resonance compatibility of the mechanical system, resulting in artifacts, noise or electromagnetic interference in MRI imaging, which can seriously affect the safety of the equipment and patients.

[0007] (2) The internal space of the MRI cabin is relatively narrow, and the existing large or bulky mechanical structures are difficult to flexibly arrange in a compact environment, which limits the operation process and affects the treatment efficiency;

[0008] (3) The existing MRI-compatible machines only have simple movement or limited angle rotation, which makes it difficult to achieve multi-angle accurate positioning of complex lesions, limiting their applicability in applications in multiple parts such as the prostate, spine, and breast;

[0009] (4) The existing technology mostly uses complex transmission chains as transmission, or Figure 1 In the process, a cart or a mobile platform is used as the mobile device 210. The transmission itself or material deformation makes it difficult for the mechanical system to maintain high positioning accuracy and stability, and position deviation is prone to occur during repeated operations, affecting the treatment effect.

[0010] Based on the above technical bottlenecks, there is an urgent need for a mechanical system that is specifically adapted to the MRI environment, can achieve flexible control in multiple degrees of freedom and has high-precision positioning capabilities. It not only meets the strict requirements of non-magnetic materials and miniaturization, but also can cover the diagnosis and treatment needs of multiple parts such as the prostate, spine, and breast, and ensure safety, reliability and ease of operation in actual treatment. Summary of the invention

[0011] The main purpose of the present invention is to provide a multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment, which realizes precise adjustment of the puncture mechanism in three-dimensional space and posture angle by setting and interlinking the differential mechanism, the upper and lower scissors mechanism, and the direction limiting mechanism to meet various puncture and ablation requirements. The mechanical system provided by the present application can completely avoid the use of magnetic materials and metal motors, so that the mechanical system of the present application has high magnetic resonance compatibility. At the same time, its structure is streamlined and can be flexibly arranged and implemented in a compact environment. The present application specifically adopts the following technical solutions:

[0012] A multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment, comprising:

[0013] Fixed base;

[0014] An upper scissor mechanism and a lower scissor mechanism installed via the fixed base;

[0015] A differential mechanism, comprising two groups, driving the upper scissor mechanism and the lower scissor mechanism respectively;

[0016] A joint rotating rod, the upper end of which is connected to the working end of the upper scissor mechanism through a guide fit, and the lower end of which is connected to the working end of the lower scissor mechanism through a ball joint fit;

[0017] The puncture mechanism is fixedly mounted on the upper end of the joint rotation rod.

[0018] Preferably, the working ends of the upper scissors-fork mechanism and the lower scissors-fork mechanism extend out of the fixed base, and the extending length of the working end of the lower scissors-fork mechanism is greater than that of the working end of the upper scissors-fork mechanism.

[0019] Preferably, the differential mechanism is realized by two sets of threaded mechanisms, and its power is an ultrasonic motor.

[0020] Preferably, the upper scissors-type mechanism comprises a third long link, a fifth long link, a sixth long link and a fourth long link which are hinged in sequence head to tail, one end of the first long link is hinged to the middle part of the third long link, and the other end is hinged to the output end of the differential mechanism, one end of the second long link is hinged to the middle part of the fourth long link, and the other end is hinged to the output end of the differential mechanism, and the hinge points of the fifth long link and the sixth long link are the working ends of the upper scissors-type mechanism.

[0021] Preferably, the lower scissors-type mechanism comprises a third short link, a fifth short link, a sixth short link and a fourth short link which are hinged in sequence head to tail, one end of the first short link is hinged to the middle part of the third short link, and the other end is hinged to the output end of the differential mechanism, one end of the second short link is hinged to the middle part of the fourth short link, and the other end is hinged to the output end of the differential mechanism, and the hinge point of the fifth short link and the sixth short link is the working end of the lower scissors-type mechanism.

[0022] Preferably, the mechanical system also includes a limiting connecting rod, which includes an upper cross bar, a lower cross bar and a vertical rod connecting the two, the third long connecting rod and the fourth long connecting rod are jointly hinged on the upper cross bar, and the third short connecting rod and the fourth short connecting rod are jointly hinged on the lower cross bar.

[0023] Preferably, the upper scissors mechanism also includes a seventh long link and an eighth long link hinged to each other, and a direction limiting mechanism; the free end of the seventh long link is hinged to the middle part of the fifth long link, and the free end of the eighth long link is hinged to the middle part of the sixth long link; the direction limiting mechanism includes a first sliding bar and a second sliding bar arranged parallel to each other, a front rotating seat fixedly connected to the front ends of the first sliding bar and the second sliding bar, a rear rotating seat capable of sliding along the first sliding bar and the second sliding bar, a limiting connecting block fixedly connected to the rear ends of the first sliding bar and the second sliding bar, and a rotating slider capable of being relatively rotatably mounted on the front rotating seat, the bottom of the front rotating seat can be relatively rotatably mounted at the hinge point of the fifth long link and the sixth long link, the bottom of the rear rotating seat can be relatively rotatably mounted at the hinge point of the seventh long link and the eighth long link, and the rotating slider is connected to the upper end of the joint rotating rod by guiding cooperation.

[0024] Preferably, the rotating slider includes a rotating shaft arranged through the front rotating seat, one end of the rotating shaft is limited by a nut, and the other end is fixed with a pair of inserts, and the short shaft passes through the pair of inserts and is fixed; a long slide groove is opened at the upper end of the joint rotating rod, the long slide groove is located between the pair of inserts and the short shaft passes through the long slide groove.

[0025] Preferably, the puncture mechanism includes a base, with a front end and a rear end fixedly provided at both ends of the base respectively, a slide groove is provided on the top surface of the base located between the front end and the rear end, and a fixed installation groove is provided on the top surface of the front end, and the push slider cooperates with the slide groove and can slide along the slide groove under the drive of the servo screw mechanism.

[0026] A multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment using the technical solution of the present application, each mechanism is made of non-magnetic material and has good magnetic resonance compatibility. At the same time, through two sets of differential mechanisms as drive, the same-direction and reverse differentials of the differential mechanisms can realize the directional movement of the puncture mechanism on the horizontal plane. Furthermore, the upper and lower scissor-fork mechanisms adopt a scissor-fork structure with a deformed design, so that the two can be extended and retracted while also being able to move left and right. Therefore, when the upper and lower scissor-fork mechanisms respectively control the upper and lower ends of the joint rotating rod, in combination with the translational freedom of the puncture mechanism, the puncture mechanism can obtain three translational degrees of freedom and two rotational degrees of freedom.

[0027] In a preferred embodiment, by setting a limit connecting rod, on the one hand, the freedom of the mechanical system can be expanded, and on the other hand, the relative position of the upper and lower scissors mechanism can be kept unchanged, and by changing the length of the limit connecting rod, the change of the movement area can be achieved.

[0028] In a preferred embodiment, by setting a limiting mechanism, it is possible to ensure that the direction of the rotating slider is always consistent with the axial direction of the upper scissor mechanism, thereby improving the stability and reliability of the mechanical system and ensuring the accuracy of the treatment operation. At the same time, using two sets of threaded mechanisms to achieve a differential function can improve the accuracy and stability of the transmission, thereby also ensuring the accuracy of the treatment operation.

[0029] Additionally, a multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment using the technical solution of the present application has a relatively streamlined structure and can be flexibly arranged in a relatively small space.

[0030] To sum up, the multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment provided in this application is specially adapted to the MRI environment. It can realize flexible control of multiple degrees of freedom and has high-precision positioning capability. It not only meets the strict requirements of non-magnetic materials and miniaturization, but also can cover the diagnosis and treatment needs of multiple parts such as prostate, spine, breast, etc., and ensure safety, reliability and easy operation in actual treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings constituting a part of the present application are used to provide a further understanding of the invention. 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:

[0032] Figure 1 It is a schematic diagram of a puncture robot system in the prior art.

[0033] Figure 2 It is a structural schematic diagram from one perspective of a multi-degree-of-freedom mechanical system that can be optionally used for magnetic resonance-guided interventional treatment according to an embodiment of the present invention.

[0034] Figure 3 It is a structural schematic diagram from another perspective of a multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment that can be optionally used according to an embodiment of the present invention.

[0035] Figure 4 It is a structural schematic diagram of an optional differential mechanism according to an embodiment of the present invention.

[0036] Figure 5 It is a structural schematic diagram of an optional upper scissor mechanism according to an embodiment of the present invention.

[0037] Figure 6 It is a structural schematic diagram of an optional lower scissor mechanism according to an embodiment of the present invention.

[0038] Figure 7 It is a structural schematic diagram of an optional direction limiting mechanism according to an embodiment of the present invention.

[0039] Figure 8 It is a structural schematic diagram of an optional joint rotation mechanism and puncture mechanism according to an embodiment of the present invention.

[0040] Fig. 9 It is a schematic cross-sectional structure diagram of a multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional treatment that can be optionally used according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Example

[0043] See also Figures 2 to 9 A multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy shown in the figure comprises at least a fixed base 100, a differential mechanism 200, an upper scissor mechanism 300, a lower scissor mechanism 400, a joint rotation rod 700 and a puncture mechanism 800. The mechanical system provided in this embodiment may have an independent control system, such as any one of the prior art, and may also be connected to a magnetic resonance system.

[0044] The fixed base 100 is a frame structure of the prior art, which is suitable for providing space and support for the installation of other mechanisms and components of the mechanical system.

[0045] The differential mechanism 200 includes two groups. The two groups of differential mechanisms 200 are symmetrically arranged up and down. The differential mechanism 200 includes a base plate 201 screwed or welded on the fixed base 100, and two groups of threaded mechanisms are screwed or welded on the base plate 201. The threaded mechanism can be a prior art. The first threaded mechanism provided in this embodiment includes a first support 202 fixedly mounted on the base plate 201, a first transmission screw 204, a first coupling 206, a first ultrasonic motor 208, a first slider 210 and at least one first optical axis 212 arranged parallel to the first transmission screw 204. Specifically, the first transmission screw 204 can be rotatably mounted on the first support 202, one end of which is connected to the output end of the first ultrasonic motor 208 through the coupling 206, a threaded hole and a light hole are opened in the axial direction on the first slider 210, the first transmission screw 204 passes through the threaded hole, the first optical axis 212 passes through the light hole, and the top surface of the first slider 210 is fixedly provided with a first hinge axis. The first thread mechanism can realize axial movement of the first hinge shaft.

[0046] Correspondingly, the second thread mechanism provided in this embodiment includes a second support 203 fixedly mounted on the base plate 201, a second transmission screw 205, a second coupling 207, a second ultrasonic motor 209, a second slider 211 and at least one second optical axis 213 arranged parallel to the second transmission screw 205. Specifically, the second transmission screw 205 can be rotatably mounted on the second support 203, and the two ends are connected to the output end of the second ultrasonic motor 209 through the coupling 207. The second slider 211 is provided with a threaded hole and a light hole in the axial direction, the second transmission screw 205 passes through the threaded hole, and the second optical axis 213 passes through the light hole, and the top surface of the second slider 211 is fixedly provided with a second hinge shaft. The second thread mechanism can realize the axial movement of the second hinge shaft, and the asynchronous movement of the first hinge shaft and the second hinge shaft can realize differential output.

[0047] The upper scissor mechanism 300 provided in this embodiment includes a third long link 303, a fifth long link 305, a sixth long link 306 and a fourth long link 304 which are hinged in sequence from head to tail, one end of the first long link 301 is hinged to the middle of the third long link 303, and the other end is hinged to the output end of the differential mechanism 200, that is, it is hinged to the first hinge shaft of the differential mechanism 200 arranged above, one end of the second long link 302 is hinged to the middle of the fourth long link 304, and the other end is hinged to the output end of the differential mechanism 200, that is, it is hinged to the second hinge shaft of the differential mechanism 200 arranged above. The hinge point of the fifth long link 305 and the sixth long link 306 is the working end of the upper scissor mechanism 300, which extends out of the fixed base 100.

[0048] The lower scissor mechanism 400 provided in this embodiment includes a third short link 403, a fifth short link 405, a sixth short link 406 and a fourth short link 404 which are hinged in sequence from head to tail, one end of the first short link 401 is hinged to the middle of the third short link 403, and the other end is hinged to the output end of the differential mechanism 200, that is, it is hinged to the first hinge shaft of the differential mechanism 200 arranged below, one end of the second short link 402 is hinged to the middle of the fourth short link 404, and the other end is hinged to the output end of the differential mechanism 200, that is, it is hinged to the second hinge shaft of the differential mechanism 200 arranged below. The hinge point of the fifth short link 405 and the sixth short link 406 is the working end of the lower scissor mechanism, which extends out of the fixed base 100, and its extension length is greater than the working end of the upper scissor mechanism 300.

[0049] In a specific implementation, the hinge points of the third long link 303 and the fourth long link 304 can be hinged on the base 201 of the upper differential mechanism 200, and the hinge points of the third short link 403 and the fourth short link 404 can be hinged on the base 201 of the lower differential mechanism 200, so as to fix the upper scissors-fork mechanism 300 and the lower scissors-fork mechanism 400.

[0050] More preferably, the mechanical system provided in this embodiment further includes a limit connecting rod 600. The limit connecting rod 600 includes an upper cross bar 601, a lower cross bar 602 and a vertical rod 603 connecting the two, the third long connecting rod 303 and the fourth long connecting rod 304 are hinged together on the upper cross bar, and the third short connecting rod 403 and the fourth short connecting rod 404 are hinged together on the lower cross bar 602. The advantage of this solution is that the degree of freedom of the mechanical system can be further improved. At the same time, the setting of the limit connecting rod 600 can also keep the relative position of the upper and lower scissor-fork mechanisms 300, 400 unchanged, and by changing the length of the limit connecting rod 600, the change of the motion area can be achieved.

[0051] At the same time, as another preferred technical solution, the upper scissor mechanism 300 also includes a seventh long link 307 and an eighth long link 308 that are hinged to each other, and a direction limiting mechanism 500. The free end of the seventh long link 307 is hinged to the middle of the fifth long link 305, and the free end of the eighth long link 308 is hinged to the middle of the sixth long link 306. The direction limiting mechanism 500 includes a first slide bar 504 and a second slide bar 505 that are arranged in parallel to each other. The first slide bar 504 and the second slide bar 505 are regarded as a slide bar group. The front end of the slide bar group is fixedly provided with a front rotating seat 501, and the rear end is fixedly provided with a limited position connection block 506. A pair of light holes are opened in the axial direction on the rear rotating seat 502. The slide bar group passes through the light holes so that the rear rotating seat 502 can slide along the slide bar group. The bottom of the front rotating seat 501 is relatively rotatably mounted at the hinge point of the fifth long link 305 and the sixth long link 306 via a short shaft, and the bottom of the rear rotating seat 502 is relatively rotatably mounted at the hinge point of the seventh long link 307 and the eighth long link 308 via a short shaft. A rotating slider 503 is relatively rotatably mounted on the front rotating seat 501, and the rotating slider 503 is connected to the upper end of the joint rotating rod 700 via a guide fit.

[0052] Specifically, the rotating slider 503 includes a rotating shaft 507 that passes through the front rotating seat, one end of the rotating shaft 507 is limited by a nut 508, and the other end is fixed with a pair of inserts 509, and the short shaft 510 passes through the pair of inserts 509 and is fixed. A long slide groove 701 is opened at the upper end of the joint rotating rod 700, and the long slide groove 701 is located between the pair of inserts 509 and the short shaft 510 is set through the long slide groove 701, so that the upper end of the joint rotating rod 700 is connected to the working end of the upper scissor mechanism 300 through a guide fit. The lower end of the joint rotating rod 700 has a ball joint that is connected to the working end of the lower scissor mechanism 400 through a ball joint fit. Compared with the technical solution that the upper end of the joint rotating rod 700 is directly connected to the working end of the upper scissor mechanism through a guide fit, this preferred technical solution can further improve the degree of freedom of the mechanical system.

[0053] The puncture mechanism 800 is screwed or welded and fixedly installed on the upper end of the joint rotating rod 700. The puncture mechanism 800 provided in this embodiment includes a base, which has a certain length along its axial direction, and the two ends of the base are respectively provided with a front end 806 and a rear end 807 in an integral manner, and a slide groove 801 is provided on the top surface of the base between the front end 806 and the rear end 807, and a fixed installation groove 805 is provided on the top surface of the front end 806, and a push slider 804 is matched with the slide groove 801 and can slide along the slide groove under the drive of the servo screw mechanism. The servo screw mechanism may be of the prior art. This embodiment provides a servo screw mechanism, including a transmission screw 803 rotatably mounted on the front end 806 and the rear end 807, a small drive motor 802 driving the transmission screw 803, a push slider 804 having a threaded hole along its axial direction, the transmission screw 803 passing through the threaded hole and threadedly engaged therewith, and under the drive of the small drive motor 802 and the limiting action of the slide 801, the push slider 804 can move along the slide 801. Preferably, the small drive motor 802 is a small ultrasonic motor to avoid interference with magnetic resonance imaging.

[0054] The puncture tool can be fixedly installed in the fixed installation groove 805, and is pushed by the push slider 804 to perform puncture. The above scheme can control the puncture action more accurately and can adapt to the installation of various puncture tools.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy, characterized in that: include: Fixed base; An upper scissor mechanism and a lower scissor mechanism installed via the fixed base; A differential mechanism, comprising two groups, driving the upper scissor mechanism and the lower scissor mechanism respectively; A joint rotating rod, the upper end of which is connected to the working end of the upper scissor mechanism through a guide fit, and the lower end of which is connected to the working end of the lower scissor mechanism through a ball joint fit; The puncture mechanism is fixedly mounted on the upper end of the joint rotation rod.

2. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 1, characterized in that: The differential mechanism is realized by two sets of screw mechanisms, and its power is an ultrasonic motor.

3. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 1, characterized in that: The upper scissors-type mechanism comprises a third long link, a fifth long link, a sixth long link and a fourth long link which are hinged in sequence head to tail, one end of the first long link is hinged to the middle part of the third long link, and the other end is hinged to the output end of the differential mechanism, one end of the second long link is hinged to the middle part of the fourth long link, and the other end is hinged to the output end of the differential mechanism, and the hinge point of the fifth long link and the sixth long link is the working end of the upper scissors-type mechanism.

4. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 3, characterized in that: The lower scissors-type mechanism includes a third short link, a fifth short link, a sixth short link and a fourth short link which are hinged in sequence head to tail. One end of the first short link is hinged to the middle of the third short link, and the other end is hinged to the output end of the differential mechanism. One end of the second short link is hinged to the middle of the fourth short link, and the other end is hinged to the output end of the differential mechanism. The hinge point of the fifth short link and the sixth short link is the working end of the lower scissors-type mechanism.

5. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 4, characterized in that: The mechanical system also includes a limiting connecting rod, which includes an upper cross bar, a lower cross bar and a vertical rod connecting the two, the third long connecting rod and the fourth long connecting rod are jointly hinged on the upper cross bar, and the third short connecting rod and the fourth short connecting rod are jointly hinged on the lower cross bar.

6. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 3, characterized in that: The upper scissors mechanism also includes a seventh long link and an eighth long link hinged to each other, and a direction limiting mechanism; the free end of the seventh long link is hinged to the middle part of the fifth long link, and the free end of the eighth long link is hinged to the middle part of the sixth long link; the direction limiting mechanism includes a first sliding bar and a second sliding bar arranged in parallel with each other, a front rotating seat fixedly connected to the front ends of the first sliding bar and the second sliding bar, a rear rotating seat capable of sliding along the first sliding bar and the second sliding bar, a limiting connecting block fixedly connected to the rear ends of the first sliding bar and the second sliding bar, and a rotating slider mounted on the front rotating seat capable of relative rotation, the bottom of the front rotating seat being relatively rotatably mounted at the hinge point of the fifth long link and the sixth long link, the bottom of the rear rotating seat being relatively rotatably mounted at the hinge point of the seventh long link and the eighth long link, and the rotating slider is connected to the upper end of the joint rotating rod by guiding cooperation.

7. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 6, characterized in that: The rotating slider includes a rotating shaft that passes through the front rotating seat, one end of the rotating shaft is limited by a nut, and the other end is fixed with a pair of inserts, and the short shaft passes through the pair of inserts and is fixed; a long slide groove is opened at the upper end of the joint rotating rod, the long slide groove is located between the pair of inserts and the short shaft passes through the long slide groove.

8. The multi-degree-of-freedom mechanical system for magnetic resonance-guided interventional therapy according to claim 1, characterized in that: The puncture mechanism includes a base, and the two ends of the base are respectively fixed with a front end and a rear end. The top surface of the base between the front end and the rear end is provided with a slide groove, and the top surface of the front end is provided with a fixed installation groove. The push slider cooperates with the slide groove and can slide along the slide groove under the drive of the servo screw mechanism.

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