Verification method and ct verification phantom for surgical navigation robotic system

Abstract

The application provides a verification method for a surgical navigation robot system and a CT verification phantom, the CT verification phantom comprising at least one measuring module and a base, wherein each of the measuring modules is substantially cylindrical, has two substantially parallel measuring end faces, and has a certain height removed on both axial sides, thereby forming two planes on the side faces; the base is substantially plate-shaped, and the measuring modules are fixed to the base through fixing devices; the measuring modules, the base and the fixing devices are all made of high-molecular organic materials. The method and the CT verification phantom have high stability and simple structure, can be used for measuring the precision of image reconstruction, image registration, surgical navigation and tracking, image fusion and the like of the surgical navigation robot system in application, and can also verify the surgical navigation / tracking precision, early warning, surgical path planning and the like of the surgical navigation system.

Description

Technical Field

[0001] This invention relates to a verification method for a surgical navigation robot system, and a CT verification phantom for verifying a surgical navigation robot system, belonging to the field of medical device quality control and inspection technology. Background Technology

[0002] In medical applications, professional phantoms with high accuracy and stability are typically used as standard tools to accurately and objectively evaluate the image reconstruction quality, computational accuracy, resolution, and other application effects in medical applications.

[0003] The application of surgical navigation robot systems involves complex planning and calculation processes, including patient CT image scanning, patient model reconstruction, real-time surgical tracking, lesion delineation, surgical planning, and spatial registration and fusion of navigation images.

[0004] A surgical navigation robot system generally includes a robot system, an application system, and a navigation system. The robot system is used to move and precisely position surgical end effectors such as probes; the application system is used to perform 3D reconstruction of surgery-related CT images, surgical planning, and can measure the reconstructed model and surgical plan; the navigation system tracks the path and position of the end effector in real time according to the set surgical plan.

[0005] Currently, performance evaluation of surgical navigation robot systems primarily utilizes phantoms and methods provided by equipment manufacturers to test technical indicators such as the robot system's movement accuracy, patient model reconstruction accuracy, spatial registration and fusion, and positioning and tracking performance. Professor Duan Xingguang employed a cranial positioning frame method to measure the spatial registration and positioning accuracy of a craniofacial surgical robot. Zhang Weijun invented two accuracy testing devices for surgical navigation robot systems, capable of measuring the positioning accuracy and verifying the surgical planning path. S. Olive invented an automatic reconstruction and calibration device for tracking the patient's anatomical structure position and coordinate system during surgery. Professor Duan Xingguang's method has a relatively complex structure and requires the use of titanium metal markers to assist in patient image scanning and positioning. Zhang Weijun's method has a simpler structure, but in practical use, human factors have a significant impact, requiring careful operation, and the accuracy and repeatability of the test need improvement. S. Olive's method is only applicable to intraoperative X-ray tracking. All of the above methods require the use of metal target sphere imaging, which is prone to artifacts.

[0006] Currently, 3D printing is widely used in mold manufacturing. 3D printing is a layer-by-layer additive manufacturing process, characterized by its high printing speed and one-step molding capabilities, enabling the printing of three-dimensional models that are difficult to produce otherwise. However, due to the layer-by-layer molding method used in 3D printing, the dimensional accuracy and surface roughness of the printed molds are far lower than those produced by traditional machining. Furthermore, the strength, rigidity, and fatigue resistance of the printed molds are also inferior.

[0007] An investigation into 3D printing materials revealed that most materials suitable for high-precision printing are metallic, which are unsuitable for imaging scans in CT and MR systems. If materials such as plastics, ceramics, resins, or waxes are used for 3D printing, the printing accuracy is lower, and the mold is more susceptible to deformation due to temperature variations. 3D printed molds are suitable for short-term model design verification during the R&D phase but cannot be used for quality control in imaging equipment.

[0008] Furthermore, surgical navigation robot systems have more requirements for CT verification phantoms than in other applications, requiring them to possess the following characteristics:

[0009] 1. It has defined spatial measurement points for performance measurement of surgical navigation robot systems;

[0010] 2. The materials used are non-metallic materials with good stability and high transparency, and are easy to process;

[0011] 3. CT images have high contrast and are clear;

[0012] 4. High machining accuracy and stable measurement point selection location;

[0013] 5. Easy to operate and quick to measure;

[0014] 6. Capable of verifying the accuracy of dimensional and distortion measurements in the reconstruction of anatomical models of patients from CT images;

[0015] 7. It possesses specific marker points and surfaces, which can meet the requirements for image registration and fusion accuracy verification;

[0016] 8. Capable of verifying the positioning accuracy and navigation / tracking early warning capabilities of surgical navigation / tracking;

[0017] 9. It can satisfy the verification of the fusion effect of endoscopic images and patient model images.

[0018] Therefore, to ensure the accuracy and safety of the surgical navigation robot system, it is necessary to design a CT verification phantom with high stability and simple structure for measuring the accuracy of image reconstruction, image registration, surgical navigation and tracking, and image fusion in the application of the surgical navigation robot system, as well as to verify the surgical navigation / tracking accuracy, early warning, and surgical path planning of the surgical navigation system. Summary of the Invention

[0019] The purpose of this invention is to provide a convenient, fast, and accurate method and CT phantom for verifying surgical navigation robot systems, thereby improving verification efficiency and measurement results.

[0020] The technical solution of the present invention is as follows.

[0021] The first aspect of the present invention provides a verification phantom for a surgical navigation robot system, comprising at least one measurement module and a base, wherein...

[0022] Each of the measurement modules is basically cylindrical, with two basically parallel measurement end faces, and a certain height is removed from each side of the axial direction, thereby forming two planes on the side.

[0023] The base is basically plate-shaped, and the measuring module is fixed to the base by a fixing device.

[0024] The measuring module, the base, and the fixing device are all made of high-molecular organic materials.

[0025] Preferably, each measuring end face of the measuring module is provided with a measuring collimation hole, the diameter of which is adapted to the end face diameter of the probe of the surgical navigation robot.

[0026] Preferably, the cylindrical surface of the measurement module is engraved with multiple “╳”-shaped marks as surface registration reference points.

[0027] Preferably, the measurement module and the movable module are respectively machined with a region selection registration plane.

[0028] Preferably, each measuring end face of the measuring module is provided with a marking hole to distinguish different measuring end faces. Preferably, the fixing device includes a fixing bolt, which is made of transparent polyoxymethylene (POM) material.

[0029] Preferably, it further includes a movable module and an auxiliary module;

[0030] The movable module and the auxiliary module can be detachably combined to form a column with a cross-section substantially the same as that of the measuring module.

[0031] Preferably, the polymer material is polymethyl methacrylate (PMMA).

[0032] A second aspect of the present invention provides a verification method for a surgical navigation robot system, comprising the following steps:

[0033] Step 1: Input the CT image scan data of the verification phantom according to any one of the first aspects of the present invention;

[0034] Step 2: Perform three-dimensional reconstruction of the image using the CT image scan data, and measure the three-dimensional reconstruction accuracy of the surgical navigation robot system using the measurement holes of different measurement end faces;

[0035] Step 3: Use the “X” mark on the verification phantom or the region of the verification phantom to select the registration plane as the registration reference point for image registration; after registration, remove the movable module of the verification phantom and use the measurement holes on different measurement end faces to measure the registration accuracy and fusion accuracy of the surgical navigation robot system;

[0036] Step 4: Select multiple measurement holes on any number of measurement end faces as surgical path reference points and surgical location points to be reached, and perform surgical planning and path planning; the surgical navigation robot system moves the probe to the surgical location point and tracks the path and position of the probe to verify the navigation / tracking accuracy and navigation / tracking early warning capability of the surgical navigation robot.

[0037] Preferably, the CT image scan data of the verification phantom is scan data in DICOM3 format.

[0038] A third aspect of the present invention provides a method for manufacturing a verification phantom according to any one of the first aspects of the present invention, comprising the following steps:

[0039] Construct a model of the verification phantom according to any one of the first aspects of the present invention;

[0040] The measurement module and base plate of the verification phantom are fabricated or printed using polymethyl methacrylate (PMMA) or other materials;

[0041] A fixture for fabricating or printing the verification phantom using transparent polyoxymethylene (POM) or other materials;

[0042] The measuring module is fixed to the base plate using the fixing device.

[0043] Through the above technical solutions, the present invention can achieve the following beneficial technical effects.

[0044] The CT verification phantom of the present invention can be used to measure the accuracy of image reconstruction, image registration, surgical navigation and tracking, and image fusion in surgical navigation robot systems. It can also be used to verify the surgical navigation / tracking accuracy, early warning, and surgical path planning of surgical navigation systems. Furthermore, it can be used to verify the accuracy of patient anatomical model reconstruction, model registration and fusion, and positioning of surgical navigation robot systems.

[0045] The CT verification phantom of this invention uses polymethyl methacrylate (PMMA) as the base material, which has the characteristics of high stability, aging resistance, high transparency, low coefficient of thermal expansion, acid resistance, alkali resistance, oil resistance, and easy processing. The raw material price and processing price are relatively low. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a simplified verification phantom structure for a surgical navigation robot system according to the present invention;

[0047] Figure 2 This is a schematic diagram of a head and neck verification phantom structure according to another embodiment of the present invention;

[0048] Figure 3 yes Figure 2 An exploded view of the head and neck verification phantom.

[0049] The meanings of the various labels in the figure are as follows:

[0050] 1. First measurement module; 2. Second measurement module; 3. Movable module; 4. Auxiliary module; 5. Base; A. Positioning hole; B. Registration plane. Detailed Implementation

[0051] Example 1

[0052] This embodiment provides a verification phantom for a surgical navigation robot. (See attached...) Figure 1 As shown, the simplest verification phantom includes at least one measurement module and a base.

[0053] Each of the measurement modules is basically cylindrical, with two basically parallel measurement end faces, and a certain height is removed from each side of the axial direction, thereby forming two planes on the side.

[0054] The base is basically plate-shaped, and the measuring module is fixed to the base by a fixing device.

[0055] The measuring module, the base, and the fixing device are all made of high-molecular organic materials.

[0056] In a preferred embodiment, the verification phantom is a cylinder with a length of 220 mm and a diameter of 160 mm as the basis for the phantom design. To facilitate measurement and phantom fixation in practical applications, 10 mm of the cylindrical surface is removed from each side along the axial direction to facilitate the installation of the verification phantom and the fixation of the image positioning and tracking device.

[0057] In a preferred embodiment, each measuring end face of the measuring module is provided with a measuring collimation hole, the diameter of which is adapted to the end face diameter of the probe of the surgical navigation robot.

[0058] Based on the probe measurement parameters used in the surgical navigation robot system, the diameter of each measurement hole is selected from the actual probe head size. In a more preferred embodiment, the measurement hole diameter is 1mm to 3mm, which allows for clear imaging in CT imaging equipment.

[0059] In a preferred embodiment, a plurality of X-shaped marks are engraved on the cylindrical surface of the measurement module as surface registration reference points.

[0060] In a preferred embodiment, the cylindrical surface of the measurement module has multiple registration planes as registration reference points for region selection.

[0061] In a preferred embodiment, each measuring end face of the measuring module is provided with a marking hole to distinguish different measuring end faces.

[0062] Although the simplest verification phantom in the above embodiments consists of a measurement module and a base, the present invention is not limited thereto. Those skilled in the art will understand that each measurement module has two measurement end faces, thus allowing for the design of multiple measurement modules to increase the number of measurement end faces as needed.

[0063] The design of the verification phantom needs to avoid the use of metal materials to reduce imaging artifacts, and all materials used are selected from high-molecular organic materials.

[0064] In a preferred embodiment, the main materials of the verification model, such as the test module, fixing pin, and fixing base plate, are selected from PMMA material, which has high stability.

[0065] In a preferred embodiment, the fixing device includes fixing bolts made of transparent polyoxymethylene (POM) material with high mechanical strength, high rigidity, high hardness, and high impact strength.

[0066] The designed mold body weighs no more than 7kg, making it easy to use in various situations.

[0067] Example 2

[0068] Appendix Figure 2-3The illustration shows an embodiment of a head and neck CT verification phantom according to the present invention. The verification phantom includes a first measurement module 1, a second measurement module 2, a movable module 3, an auxiliary module 4, and a base 5, as well as fixing pins, bolts, etc. The first measurement module 1, the second measurement module 2, the movable module 3, the auxiliary module 4, the base, and the fixing pins and bolts are all made of high-molecular organic materials.

[0069] On the two cylindrical end faces of the first measurement module 1 and the second measurement module 2, marking holes with a diameter of 1mm to 3mm and a depth of 5mm are selected as measurement collimation holes according to the end face diameter of the probe of the surgical navigation robot system. These holes are used to verify the accuracy measurements of three-dimensional reconstruction, registration and fusion, navigation and positioning.

[0070] On the cylindrical surfaces of the first measurement module 1, the second measurement module 2, and the movable module 3, multiple "╳"-shaped marks are etched as surface registration points. Each "╳"-shaped mark has a line width of 1mm to 3mm, a depth of 1mm to 3mm, and a line length of 10mm, suitable for probe applications in surgical navigation robot systems. In this embodiment, the CT verification phantom is etched with 16 "╳"-shaped marks, which can be used for registration and positioning in various coordinate systems.

[0071] To facilitate differentiation of the measurement end faces, holes with a diameter of 5 mm and a depth of 5 mm are machined on each measurement end face of the first measurement module 1 and the second measurement module 2 to distinguish between different measurement end faces. In this embodiment, the four measurement end faces of the two measurement modules are marked in different quadrants of the four end faces.

[0072] The movable module 3 and the auxiliary module 4 can be detachably combined to form a column with a cross-section that is substantially the same as that of the first measuring module 1 and the second measuring module 2.

[0073] In a preferred embodiment, region selection registration planes B are respectively machined on the first measurement module 1, the second measurement module 2, and the movable module 3. These planes are used to simulate the delineation of region selection registration. The depth of the registration planes B is 0.5 mm to 1.5 mm, suitable for applications using probes in surgical navigation robot systems. In this example, three region selection registration planes B are machined.

[0074] In addition, CT marker lines are engraved on the surface of the phantom for alignment with the CT equipment, facilitating verification of the phantom's placement on the CT equipment's diagnostic table. The CT marker lines are engraved at right angles, with a depth of 0.5 mm and an opening width of 1 mm.

[0075] Four positioning holes A were machined into the base of the verification phantom for mounting the laser tracker target ball. The diameter of the positioning holes ranges from 12.7 mm to 3 mm, which is consistent with the diameter of the tracking target ball base.

[0076] The fixing device includes fixing bolts made of transparent polyoxymethylene (POM) material.

[0077] Example 3

[0078] This embodiment provides a verification method for a surgical navigation robot system, including the following steps:

[0079] Step 1: Input CT image scan data of the verification phantom as described in either Embodiment 1 or 2.

[0080] The CT image scan data of the verification phantom can be obtained by directly using the existing DICOM3 data of the verification phantom; or, according to the requirements of the surgical navigation robot system or the actual parameters of the CT imaging equipment of the intended application unit, a suitable CT imaging device can be selected to scan the verification phantom and obtain the DICOM3 format scan data of the verification phantom.

[0081] Step 2: Perform three-dimensional reconstruction of the image using the CT image scan data, and simultaneously measure the three-dimensional reconstruction accuracy of the surgical navigation robot.

[0082] After acquiring DICOM3 data, 3D reconstruction of the image is performed. Using the measurement function of the application system, the spatial position of the measurement hole on the reconstructed measurement end face or other positions of interest are measured and compared with the actual position data of the verification phantom to obtain the accuracy of the length, spatial position, etc. after 3D reconstruction by the application system.

[0083] Step 3: Registration and fusion accuracy measurement.

[0084] Using the "X" shaped mark or region of the verification phantom, a registration plane is selected as the registration reference point. After selecting a suitable registration point using the probe of the application system, image registration is performed. After registration, the movable module 3 of the verification phantom is removed, and the spatial position of the measurement holes on each measurement end face is measured using the measurement function of the application system. This position is then compared with the actual position data of the CT verification phantom to obtain the registration accuracy and fusion accuracy data of the application system.

[0085] Step 4: Verification of the positioning accuracy of surgical navigation / tracking, and the navigation / tracking early warning capability.

[0086] After image registration and fusion are completed, the measurement hole on any measurement end face of the navigation system is selected as the surgical location point to be reached, and surgical planning and path planning are performed. An appropriate probe and tracking marker support are selected, and the probe is moved to the surgical location point. The tracking navigation function of the navigation system is used to track the path and position of the probe. The system tracking data is compared with the actual position data of the validation phantom to verify the navigation / tracking position accuracy and navigation / tracking early warning capability of the application system.

[0087] In a preferred embodiment, a step of verifying the fusion effect of endoscopic images and model images may also be included.

[0088] In the measurement end face of the verification phantom, small-interval measurement holes are machined in the central region for verifying the fusion effect of endoscopic images and model images. The endoscopic imaging area is directly aligned with the measurement hole area, and after acquiring the fused image, the positional difference of the fused holes is measured to evaluate the fusion effect of the endoscopic image and the 3D reconstructed image.

[0089] Those skilled in the art will understand that the CT verification phantom of the present invention can also be used for measurement and verification in other applications. For example, using the CT verification phantom in conjunction with a laser tracker, various precision measurements or functional verifications of surgical navigation robot systems for surgical applications can be performed.

[0090] Example 4

[0091] This embodiment provides a method for manufacturing a verification phantom according to any one aspect of the present invention, comprising the following steps:

[0092] Construct a model of the verification phantom according to any one of Embodiments 1 or 2 of the present invention;

[0093] The measurement module and base plate of the verification phantom were printed using polymethyl methacrylate (PMMA);

[0094] A fixture for printing the verification phantom using transparent polyoxymethylene (POM);

[0095] The measuring module is fixed to the base plate using the fixing device.

[0096] Those skilled in the art will understand that this embodiment can be implemented using any applicable 3D printing device in the prior art, as long as the printing material and precision meet the requirements of this invention.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A CT verification phantom for a surgical navigation robot system, comprising at least one measurement module and a base, wherein Each of the measurement modules is basically cylindrical, with two basically parallel measurement end faces, and a certain height is removed from each side of the axial direction, thereby forming two planes on the side. The base is basically plate-shaped, and the measuring module is fixed to the base by a fixing device. The measuring module, the base, and the fixing device are all made of high-molecular organic materials; Each measuring end face of the measuring module is provided with a marking hole to distinguish different measuring end faces; Each measuring end face of the measuring module is provided with a measuring collimation hole, the diameter of which is adapted to the end face diameter of the probe of the surgical navigation robot; the diameter of the measuring collimation hole is 1mm to 3mm and the depth is 5mm; The fixing device includes fixing bolts made of transparent polyoxymethylene (POM) material; The polymeric organic material is polymethyl methacrylate (PMMA).

2. The CT verification phantom for a surgical navigation robot system according to claim 1, characterized in that, The cylindrical surface of the measurement module is engraved with multiple "╳" shaped marks as surface registration reference points.

3. A CT verification phantom for a surgical navigation robot system according to claim 1, characterized in that, The cylindrical surface of the measurement module has multiple regions for selecting the registration plane.

4. A CT verification phantom for a surgical navigation robot system according to claim 1, characterized in that, It also includes movable modules and auxiliary modules made of polymer organic materials; The movable module and the auxiliary module can be detachably combined to form a column with a cross-section substantially the same as that of the measuring module.

5. A CT verification phantom for a surgical navigation robot system according to claim 4, characterized in that, The measurement module and the movable module are respectively machined with registration planes.

6. A verification method for a surgical navigation robot system, comprising the following steps: Step 1: Input the CT image scan data of the CT verification phantom according to any one of claims 1-5; Step 2: Perform three-dimensional reconstruction of the image using the CT image scan data, and measure the three-dimensional reconstruction accuracy of the surgical navigation robot system using the measurement holes of different measurement end faces; Step 3: Select a registration plane as a registration reference point using the "X" mark or area of ​​the CT verification phantom to perform image registration; after registration, remove the movable module of the CT verification phantom and use the measurement holes on different measurement end faces to measure the registration accuracy and fusion accuracy of the surgical navigation robot system; Step 4: Select multiple measurement holes on any number of measurement end faces as surgical path reference points and surgical location points to be reached, and perform surgical planning and path planning; the surgical navigation robot system moves the probe to the surgical location point and tracks the path and position of the probe to verify the navigation / tracking accuracy and navigation / tracking early warning capability of the surgical navigation robot.

7. A method for manufacturing a CT verification phantom according to any one of claims 1-5, comprising the following steps: Construct a model of the CT verification phantom according to any one of claims 1-5; The measurement module and base plate of the CT verification phantom are fabricated or printed using polymethyl methacrylate (PMMA) or other materials; Fixing device for processing or printing the CT verification phantom using transparent polyoxymethylene (POM) or other materials; The measuring module is fixed to the base plate using the fixing device.

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