Brachytherapy implantation guide plate and design method thereof

Abstract

The invention discloses a brachytherapy implantation guide plate and a design method thereof, and the method comprises the steps: S1, generating a patient body surface three-dimensional model through threshold segmentation according to the image data of a patient; s2, automatically generating vaginal tamponade, marking the position of the tamponade in a cross section image based on image data of a patient, importing a corresponding tamponade three-dimensional model, and automatically performing space registration of the three-dimensional model and the image; s3, a guide plate substrate is automatically generated, and based on the patient image data, the vulva contour is extracted to generate the guide plate substrate; s4, synthesizing the vaginal packing and the guide plate substrate, dividing the vaginal packing into a human body internal part and a human body external part by taking the contour of the guide plate substrate as a reference, deleting the human body external part, and synthesizing the remaining part and the guide plate substrate into a whole through Boolean operation; s5, generating an auxiliary device, wherein the auxiliary device comprises automatic generation of a needle inserting and implanting channel and automatic generation of an anti-springback buckle; and S6, optimizing the overall three-dimensional model, repairing the defects of the model, and exporting the model as an STL format file.

Description

Technical Field

[0001] The present invention relates to the technical field of brachytherapy medical devices, and in particular to a brachytherapy implantation guide and a design method thereof. Background Art

[0002] In recent years, in order to better improve the accuracy and repeatability of interstitial implantation therapy, 3D printed personalized templates have been introduced into afterloading radiotherapy. Individualized brachytherapy plans are formulated for patients according to different conditions. Interposition guides are customized based on the patient's imaging data and combined with the patient's physiological structure. Interposition guides are used to guide afterloading radiotherapy, which significantly improves the patient's treatment efficacy, reduces side effects, and greatly improves the patient's quality of life after treatment. The in-depth development of this technology will promote innovation in "individualized" precision treatment of tumors. In the traditional design method of 3D printed personalized templates, manual operation of three-dimensional design software (such as SolidWorks, Mimics) is required, and the design process is significantly affected by personal experience:

[0003] (1) Shape design is highly subjective, and different people have different understandings of the "ideal guide shape", which may lead to design deviations in the guide and affect patient treatment.

[0004] (2) Inefficiency and high cost. Manual design needs to go through steps such as “image segmentation-3D reconstruction-manual modeling-adjustment and optimization” and needs to be modified multiple times to meet clinical needs.

[0005] (3) Skill threshold restrictions: 3D design software is complex to operate and requires an engineering background or long-term training.

[0006] Therefore, the prior art still has the following defects:

[0007] Low design efficiency: Traditional guide plate design relies on manual adjustment of the guide plate shape. A single design takes 4-8 hours and is easily affected by experience, resulting in large differences in design results among different personnel.

[0008] Long iteration cycle: The design-verification process requires repeated manual intervention, and an average of 3-5 iterations are required to meet clinical requirements. Summary of the Invention

[0009] In response to the above technical problems, the present invention proposes a brachytherapy implantation guide and a design method thereof, which realizes the automatic generation of a brachytherapy implantation guide through image recognition, geometric calculation and three-dimensional modeling technology, and can automatically adjust the design parameters according to the patient's individual three-dimensional model, greatly improving the personalization and accuracy of the substrate design, while simplifying the design process, reducing human errors, and improving the safety and convenience of clinical use.

[0010] In order to achieve the above-mentioned purpose, the technical solution of the present invention provides a design method for a brachytherapy implantation guide, which includes: S1: generating a three-dimensional model of the patient's body surface through threshold segmentation based on the scanned patient image data; S2: automatic generation of vaginal packing, based on the patient image data, by marking the packing position in the cross-sectional image and importing the corresponding standard packing three-dimensional model, automatically performing spatial alignment between the packing three-dimensional model and the two-dimensional image; S3: automatic generation of a guide base plate, based on the patient image data, extracting the vulva contour to generate a guide base plate; S4: synthesizing the vaginal packing with the guide base plate, dividing the vaginal packing into the human body internal part and the human body external part based on the guide base plate contour, deleting the human body external part, and synthesizing the remaining part of the vaginal packing with the guide base plate into a whole through Boolean operation; S5: generation of auxiliary devices, including: S51: automatic generation of the implantation needle channel, based on the treatment The coordinates of the dwell points and the specifications of the implant needle in the treatment plan data are used to generate a three-dimensional model of the implant needle. The three-dimensional model of the implant needle is subtracted from the overall model of the vaginal packing and the guide plate base plate through Boolean operations to form an implant needle channel; S52: Anti-rebound buckles are automatically generated, the midpoint of the intersection surface of the vaginal packing and the guide plate base plate is identified, and with the midpoint as the center, the intersection range of the implant needle channel and the guide plate base plate is expanded by a preset distance as a boundary, and a first rectangular model of a certain thickness is generated in the outward direction of the human body, and the first rectangular model and the guide plate base plate are integrated through Boolean operations, and then the top surface of the first rectangular model is expanded by a preset distance to generate a second rectangular model, a groove is dug out on the interface between the two, and upper and lower matching slots and buckles are generated on the needle-free side of the second rectangular model, and finally a silicone sheet or rubber sheet is preset in the groove; S6: The overall three-dimensional model is optimized, and after repairing the model defects, it is exported as an STL format file.

[0011] Furthermore, step S2 specifically includes: S21: marking the target position of the filling in the cross-sectional image, the target position including the filling vertex in the image and the filling position in the cross-sectional layers 1-3, and then calculating the filling center point based on the marked position; S22: importing a standard filling three-dimensional model of corresponding size, and calculating the rotation matrix and translation vector based on the spatial position of the filling three-dimensional model, and the center point and vertex coordinates of the marked position; S23: moving the filling three-dimensional model to the image position based on the rotation matrix and translation vector calculated in step S22 to achieve spatial alignment of the filling three-dimensional model with the image.

[0012] Furthermore, step S3 specifically includes: S31: based on the body surface three-dimensional model obtained in step S1, extracting the vulva feature points of the body surface three-dimensional model, generating a closed contour curve, and setting the guide plate substrate contour including transverse and longitudinal dimensions based on the closed contour curve; S32: fitting the smooth guide plate substrate contour edge, and expanding the guide plate substrate contour outward a certain distance to the outside of the body according to the set thickness value to generate a guide plate substrate three-dimensional model.

[0013] Furthermore, in step S32, before expanding the guide plate base plate contour outward from the body, it also includes: generating a three-dimensional base plate model based on the guide plate base plate contour and superimposing it with the patient image, and displaying the fitting gap through color mapping; then performing local expansion compensation on the area where the gap exceeds the standard, and iteratively adjusting the guide plate base plate contour.

[0014] Furthermore, in step S31 , the lateral dimension=the lateral width of the closed contour curve+a certain safety margin, and the longitudinal dimension=the maximum length of the closed contour curve*A, wherein A is greater than 1.

[0015] Furthermore, step S5 also includes: S53: automatically generating a fixing hole, generating a third cuboid at a certain distance around the first cuboid model, generating a fixing hole of a preset diameter inside the third cuboid, and the axis of the fixing hole coincides with the central axis of the third cuboid.

[0016] Furthermore, step S5 also includes: S54: the median line, urethral opening, and catheter groove are automatically generated by matching the standard three-dimensional model of the female vulva and catheter with the point cloud features in the patient's scan data, and combining the anatomical features of the patient's three-dimensional model to determine the patient's urethral opening, vulva midline and catheter spatial position. The circular urethral opening with a diameter ≥ 2 cm is subtracted by Boolean operation. With the guide plate substrate as a reference, the protrusion is stretched upward to form a catheter groove for embedding the catheter; with the identified patient's vulva midline as a reference, a median line with a certain length, width and height is marked on the surface of the guide plate substrate upward from the urethral opening.

[0017] Furthermore, step S5 also includes: S55: automatically generating a guide column, generating a guide column perpendicular to the direction of the human body at the bottom center position of the lower side of the guide plate substrate, and the diameter and length of the guide column are set according to positioning requirements.

[0018] Furthermore, step S5 also includes: S56: automatically generating a patient information mark, and automatically generating the input patient information in a selected area on the upper side of the guide plate substrate that does not contact the human body surface.

[0019] Furthermore, step S5 also includes: S57: automatic generation of positioning holes, automatically identifying the surface lead points in the patient's anatomical image, and generating positioning holes of preset diameters on the three-dimensional model of the guide plate substrate with the lead points as the center through Boolean operations.

[0020] The technical solution of the present invention also provides a brachytherapy insertion guide, which is generated by the design method as described above, and the brachytherapy insertion guide includes: a guide base plate: generated according to the patient's body contour, and used for resetting the guide during treatment; a vaginal packing: generated according to a pre-placed vaginal packing, and used to open the patient's vagina to facilitate needle placement and resetting the patient's vagina during treatment, and the vaginal packing and the guide base plate are synthesized into a whole through Boolean operations; an insertion needle channel: formed in the overall structure of the guide base plate and the vaginal packing through Boolean operations, and used for the insertion needle to pass through; an anti-rebound buckle: used to fix the insertion needle to prevent the insertion needle from rebounding when encountering resistance and sliding during treatment, and the anti-rebound buckle includes a first rectangular model connected to the guide base plate and a second rectangular model detachably connected to the first rectangular model, the connecting surface of the first rectangular model and the second rectangular model is provided with a groove, and a silicone sheet or a rubber sheet is provided in the groove, and the needle-free side of the second rectangular model is provided with a slot and a buckle that cooperate with the first rectangular model.

[0021] Furthermore, the brachytherapy implantation guide also includes: patient information identification: used to identify patient information; positioning hole: used to coincide with the lead point identification on the patient's body surface for easy resetting; median line: the template median line is designed according to the patient's clitoris position and the midline of the vulva to facilitate the doctor to confirm the position; urethral opening: a hole is opened at the urethra position to prevent the catheter from being squeezed, so that the doctor can observe the fit between the template and the vagina and the body surface; catheter groove: a groove that conforms to the shape of the catheter, used to place and fix the catheter, and prevent the template from squeezing the catheter; fixing hole: used to cooperate with the fixing rod to cooperate with the universal wheel of the rear-mounted bed to fix the implantation guide; guide column: the direction is perpendicular to the human body and downward, used to observe the reset of the guide to determine whether the guide is rotated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 It is a plan view of a brachytherapy implantation guide of the present invention;

[0024] Figure 2A-2C It is a schematic diagram of the three-dimensional structure of the brachytherapy implant guide of the present invention;

[0025] Figure 3 This is a design flow chart of the brachytherapy implant guide of the present invention;

[0026] Figure 4 It is a detailed design flow chart of the brachytherapy implantation guide of the present invention. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] The key points of the present invention include:

[0029] (1) A gynecological tumor post-installation implantation guide with characteristic components was designed. The guide has features such as patient information, midline marking, urethral orifice, urethral groove, fixing hole, guide column, anti-rebound buckle, etc., which can better meet the application of implantation guidance.

[0030] (2) An automated modeling method was constructed, from data import (DICOM format) to guide plate STL file output, automatic modeling throughout the entire process, rapid standardized modeling, and shortening the design cycle.

[0031] (3) A complete intelligent substrate design solution was proposed. Through image recognition, geometric calculation, and 3D modeling technology, the automatic generation of brachytherapy implant guides was achieved. The design parameters can be automatically adjusted according to the patient's individual 3D model, greatly improving the personalization and accuracy of substrate design. At the same time, it simplifies the design process, reduces human errors, and improves the safety and convenience of clinical use.

[0032] (4) The design method of the anti-rebound buckle not only solves the fixation and rebound problems of the implant needle by using silicone or rubber sheets to lock the needle, but also creatively solves the fixation problem of the silicone sheet / rubber sheet and the pin guidance problem through the split buckle and corresponding needle channel design.

[0033] The present invention automatically generates a brachytherapy implant guide based on the patient's anatomical data CT / MRI, brachytherapy plan data, and clinical implant needle specifications. Figure 1 as well as Figure 2A-2C As shown, the brachytherapy implant guide consists of the following components:

[0034] Guide plate base plate: generated according to the patient's body contour and used for guide plate repositioning during treatment;

[0035] Vaginal packing: generated based on pre-placed vaginal packing, used to open the patient's vagina to facilitate needle placement and to reposition the patient's vagina during treatment;

[0036] Patient information: Identify the patient's ID and name, uterine canal angle, implant needle and other information;

[0037] Positioning hole: coincides with the lead mark on the patient's body surface, making it easy to reposition;

[0038] Median line: The median line of the template is designed according to the patient's clitoral position and vulvar midline to facilitate the doctor to confirm the position;

[0039] Urethral opening: A hole is opened at the urethra to prevent the catheter from being squeezed and to facilitate the doctor to observe the fit between the template and the vagina and body surface;

[0040] Catheter groove: The groove conforms to the shape of the catheter, making it easy to place and fix the catheter while preventing the template from squeezing the catheter;

[0041] Fixing hole: used in conjunction with the fixing rod to fix the planting guide plate with the universal wheel of the rear-mounted bed;

[0042] Guide column: The direction is perpendicular to the human body and downward, which is convenient for observing the reset of the guide plate and judging whether the guide plate is rotating;

[0043] Anti-rebound buckle: used to fix the implant needle to prevent it from rebounding when encountering resistance and sliding during treatment.

[0044] See also Figure 3 and Figure 4 The guide plate design generation process of the present invention includes the following steps:

[0045] 1. Image processing: Based on the scanned patient images CT or MRI, threshold segmentation is performed to generate a three-dimensional model of the patient's body surface.

[0046] 2. Automatic generation of vaginal packing: A standard size packing with a diameter of 1cm to 4.5cm is pre-placed in the patient's guide tube. CT or MRI images are scanned and based on the images, the packing position is specified in the cross section. The corresponding standard packing 3D model is imported and automatically aligned with the 2D model. The specific steps are as follows:

[0047] 2.1 Mark the target location of the filling in the cross-sectional image, including the filling vertex in the image and the filling location in the 1st to 3rd layers of the cross section, and calculate the filling center point based on the marked location;

[0048] 2.2 Import the 3D model of the standard filling of the corresponding size, and calculate the rotation matrix ([Rx, Ry, Rz]) and translation vector ([Tx, Ty, Tz]) according to the spatial position of the 3D model and the coordinates of the center point and vertex of the marker position.

[0049] 2.3 According to the rotation matrix and translation vector calculated in (2), move the 3D model to the image position to achieve spatial alignment between the model and the image;

[0050] 3. Automatic generation of the guide plate substrate: Extract the vulva contour to generate the guide plate substrate. The size limit is 5 to 15 cm horizontally and 10 to 30 cm vertically. Specific steps:

[0051] 3.1 Image preprocessing: denoising (median filtering) and grayscale normalization are performed on CT / MRI data to enhance tissue contrast;

[0052] 3.2 Threshold segmentation algorithm: Otsu adaptive threshold method is used to automatically separate soft tissue (vulva) from the background and generate a binary mask;

[0053] 3.3 3D reconstruction: The mask is converted into a 3D model in STL format using the Marching Cubes algorithm;

[0054] 3.4 Contour extraction: Identify vulva feature points (such as clitoris and perineal body) in the 3D model and generate closed contour curves.

[0055] 3.5 Size Limit: Set the horizontal (5-15cm) and vertical (10-30cm) ranges, and automatically calculate the optimal size based on the outline bounding box. If the horizontal width of the outline is 8cm, the system recommends the horizontal size of the substrate to be 8cm + 2cm safety margin = 10cm;

[0056] 3.6 The longitudinal length is extended by 1.2 times the maximum length of the outline to ensure that the operating area is covered;

[0057] 3.7 Morphological Adaptation Optimization: Smooth the contour edges through B-spline curve fitting to avoid sharp corners that may cause patient injuries;

[0058] 3.8 Virtual try-on: The generated 3D model of the baseplate is superimposed on the patient image, and the fit gap is displayed through color mapping (red > 1mm, green < 0.5mm);

[0059] 3.9 Automatic correction algorithm: Perform local expansion compensation for areas with excessive gaps (such as scar tissue) and iteratively adjust the substrate contour;

[0060] 3.10 Expand the substrate outline outward from the body outline by 1 to 5 mm according to the set thickness value to generate a three-dimensional model of the substrate.

[0061] 4. Automatic generation of positioning holes: Automatically identify the lead point in the image, and on the 3D model of the substrate, use Boolean operation to subtract a hole with a diameter of 5mm from the lead point as the center to obtain the positioning hole.

[0062] 5. Synthesis of vaginal packing and baseplate: Based on the baseplate outline, the vaginal packing is divided into the internal part and the external part. The external part is deleted, and the baseplate and vaginal packing are added as a whole through Boolean operation.

[0063] 6. Automatic generation of anti-rebound buckles: Identify the midpoint of the intersection of the vaginal packing and the base plate, generate a pre-planned three-dimensional model of the applicator channel, and use the midpoint of the intersection of the vaginal packing and the base plate as the center. Expand the intersection of the applicator channel and the base plate by 5 to 10 mm as the boundary. Generate a rectangular three-dimensional model 1 with a thickness of ≤5 cm outside the human body, and add it to the base plate through Boolean operation to form a whole. Expand the top surface of the rectangular model by 5 to 10 cm to generate another rectangular three-dimensional model 2. Dig out a groove with a retraction of 5 mm on the surface connected to model 1, and generate two slots and buckles with different relative sizes on the upper and lower sides on the surface without the needle channel to achieve connection with the main body. Silicone or rubber sheets can be placed in the groove to prevent the implant needle from rebounding. The specific method is as follows:

[0064] 6.1 Generation and Integration of Cuboid 3D Model 1

[0065] Midpoint identification and range determination: Calculate the coordinates of the intersection of the vaginal packing and the baseplate, and use this coordinate as the center to expand the intersection of the applicator channel and the baseplate by 5-10mm as the boundary.

[0066] Rectangular Model 1 Generation: Based on the determined boundaries, a rectangular 3D model 1 with a thickness of ≤5 cm is generated toward the outside of the human body. The size and position of the rectangular model are set according to the above boundaries to ensure that it can effectively connect with the source channel and the base plate.

[0067] Boolean operation integration: a Boolean operation (merge operation) is performed on the generated rectangular parallelepiped three-dimensional model 1 and the substrate to make the two become a whole.

[0068] 6.2 Cuboid 3D Model Generation and Groove Mining

[0069] Top surface expansion and model 2 generation: Expand the top surface of the rectangular 3D model 1 by 5-10 cm to generate another rectangular 3D model 2.

[0070] Groove excavation: A 5mm inward groove is excavated on the surface where the rectangular 3D model 2 meets the model 1. This groove can tightly fit with the silicone or rubber sheet placed later, increase the friction between the implant needle and the buckle, and further prevent the implant needle from rebounding.

[0071] 6.3 Card Slot and Buckle Generation

[0072] On the surface of the rectangular 3D model 2 without the needle channel, two slots and buckles of different relative sizes are generated. The shapes and sizes of the slots and buckles match each other, and the ingenious structural design ensures a secure connection with the main body.

[0073] 6.4 Placement of silicone or rubber sheet

[0074] Place a silicone or rubber sheet into the groove. The silicone or rubber sheet has excellent elasticity and friction, filling the gap between the groove and the implant needle, further enhancing the implant's securement. When the implant needle is subjected to external forces, the silicone or rubber sheet provides additional resistance, effectively preventing the needle from rebounding and ensuring smooth treatment.

[0075] 7. Automatic generation of fixing holes: Identify a location 5 to 10 mm below the left and right sides of the rectangular 3D model. At this location, automatically generate a rectangular 3 with a length, width, and height of 5 mm. Then, automatically create a fixing hole with a diameter of 4 mm inside the rectangular 3D model. The axis of the fixing hole coincides with the central axis of the rectangular 3D model, ensuring that the position and size of the fixing hole meet the design requirements. It is understandable that the fixing holes do not necessarily need to be located below the left and right sides of the rectangular model 1. In fact, one or more fixing holes can be generated at any location around the rectangular model 1 for backup. The principle is that they do not interfere with the implant needle and are as close to the vaginal opening as possible to achieve a more ideal fixation effect.

[0076] 8. Automatic generation of median line, urethral opening and catheter groove:

[0077] By matching a standard 3D model of the female vulva and catheter with the point cloud features from the patient scan data, and combining the anatomical features of the 3D model with the patient's urethral opening, vulvar midline, and catheter spatial location, the system then uses a Boolean operation to subtract a circular urethral opening with a diameter ≥ 2 cm. Using the baseplate as a reference, an upward protrusion is stretched to form a catheter groove. The shape and size of the groove are designed based on the diameter and orientation of the catheter to ensure smooth insertion and secure fixation. Using the identified patient's vulvar midline as a reference, a vulvar midline mark is marked on the baseplate surface, ≥ 2 cm long, 2.5 mm wide, and 1-2 mm high, above the urethral opening.

[0078] 9. Automatic Guide Column Generation: Geometric calculations are used to determine the guide column generation point at the bottom center of the baseplate. This point is then used as a starting point for the generation of a guide column perpendicular to the body. The diameter and length of the guide column are precisely set based on actual design requirements, and a precise, dimensional guide column model is automatically created using 3D modeling software. The guide column provides clear guidance for baseplate installation and positioning, ensuring proper placement on the body and improving treatment accuracy and safety.

[0079] 10. Automatic generation of patient information: The upper side of the substrate, which is not in contact with the human body, automatically generates the input patient information in the selected area. Patient information can include key information such as name, age, medical record number, treatment date, etc.

[0080] 11. Automatic generation of implantation needle channel: Identify the coordinates of the pre-planned dwell point, generate the implantation needle 3D model according to the input implantation needle diameter, and perform Boolean operation to subtract the implantation needle 3D model from the overall 3D model of the substrate generated in the above steps to generate the implantation needle channel.

[0081] 12. Model Optimization and Output: Inspect and optimize the entire 3D model of the medical assistive device, correcting any defects. Export the optimized model as an STL file and transfer it to a 3D printer for manufacturing, resulting in the actual medical assistive device.

[0082] Beneficial technical effects of the present invention:

[0083] (1) The integrated design of multiple characteristic components such as patient information, median line mark, urethral orifice, urethral groove, fixing hole, guide column, anti-rebound buckle, etc. can better meet the application of gynecological tumor implantation guidance.

[0084] (2) The anti-rebound buckle achieves better fixation and anti-rebound of the implant needle.

[0085] (3) Automated modeling methods improve modeling efficiency and consistency.

[0086] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for designing a brachytherapy implant guide, characterized in that: include: S1: Generate a 3D model of the patient's body surface through threshold segmentation based on the scanned patient image data; S2: Automatic generation of vaginal packing, based on patient imaging data, by marking the packing location in the cross-sectional image and importing the corresponding standard packing 3D model, automatically performing spatial registration between the packing 3D model and the 2D image; S3: Automatic generation of the guide plate base plate, based on the patient's imaging data, extracts the vulva contour to generate the guide plate base plate; S4: The vaginal packing is combined with the guide plate base plate. Based on the outline of the guide plate base plate, the vaginal packing is divided into an internal part and an external part. The external part is deleted, and the remaining part of the vaginal packing is combined with the guide plate base plate into a whole through Boolean operation. S5: Auxiliary device generation, including: S51: Automatically generate an implant needle channel. Generate a three-dimensional model of the implant needle based on the coordinates of the dwell point and the implant needle specifications in the treatment plan data. Subtract the three-dimensional model of the implant needle from the overall model of the vaginal packing and the guide plate base plate through Boolean operations to form the implant needle channel. S52: Automatically generate an anti-rebound buckle, identify the midpoint of the intersection of the vaginal packing and the guide plate base, and with the midpoint as the center, expand the intersection of the insertion needle channel and the guide plate base by a preset distance as the boundary, generate a first rectangular parallelepiped model of a certain thickness in the direction outward from the human body, and integrate the first rectangular parallelepiped model with the guide plate base through Boolean operation. Then, expand the top surface of the first rectangular parallelepiped model by a preset distance to generate a second rectangular parallelepiped model, dig a groove at the intersection of the two, and generate a matching slot and buckle on the side of the second rectangular parallelepiped model without the needle channel. Finally, preset a silicone sheet or rubber sheet in the groove; S6: Optimize the entire 3D model, repair model defects, and export it as an STL file.

2. The method according to claim 1, characterized in that Step S2 specifically includes: S21: Marking the target position of the filling in the cross-sectional image, the target position includes the filling vertex in the image and the filling position in the cross-sectional layers 1-3, and then calculating the filling center point based on the marked position; S22: Importing a standard filling 3D model of corresponding size, and calculating a rotation matrix and a translation vector based on the spatial position of the filling 3D model and the coordinates of the center point and vertex of the marking position; S23: According to the rotation matrix and translation vector calculated in step S22, the three-dimensional model of the filling is moved to the image position to achieve spatial alignment of the three-dimensional model of the filling and the image.

3. The method according to claim 1, characterized in that Step S3 specifically includes: S31: Based on the three-dimensional body surface model obtained in step S1, extract the vulva feature points of the three-dimensional body surface model, generate a closed contour curve, and set the guide plate substrate contour including the transverse dimension and the longitudinal dimension based on the closed contour curve; S32: Fitting the smooth edge of the guide plate base plate contour, and expanding the guide plate base plate contour outward by a certain distance toward the outside of the body according to a set thickness value, thereby generating a three-dimensional model of the guide plate base plate.

4. The method according to claim 3, characterized in that In step S32, before expanding the guide plate base plate contour outward from the body, it also includes: generating a three-dimensional base plate model based on the guide plate base plate contour and superimposing it with the patient image, and displaying the fitting gap through color mapping; then performing local expansion compensation on the area where the gap exceeds the standard, and iteratively adjusting the guide plate base plate contour.

5. The method according to claim 4, characterized in that In step S31 , the horizontal dimension=the horizontal width of the closed contour curve+a certain safety margin, and the vertical dimension=the maximum length of the closed contour curve*A, where A is greater than 1.

6. The method according to claim 1, wherein Step S5 further includes: S53: Automatically generate a fixing hole. Generate a third cuboid at a certain distance around the first cuboid model. Generate a fixing hole with a preset diameter inside the third cuboid. The axis of the fixing hole coincides with the central axis of the third cuboid.

7. The method according to claim 1, characterized in that Step S5 further includes: S54: The median line, urethral opening, and catheter groove are automatically generated by matching the standard 3D model of the female vulva and catheter with the point cloud features in the patient's scan data, and combining the anatomical features of the patient's 3D model to determine the spatial position of the patient's urethral opening, vulva midline, and catheter. A Boolean operation is performed to subtract the circular urethral opening with a diameter ≥ 2 cm. Based on the guide plate base plate, the protrusion is stretched upward to form a catheter groove for embedding the catheter. Based on the identified patient's vulva midline, a median line with a certain length, width, and height is marked on the surface of the guide plate base plate upward from the urethral opening.

8. The method according to claim 1, characterized in that Step S5 further includes: S55: A guide column is automatically generated. A guide column perpendicular to the direction of the human body is generated at the bottom center of the lower side of the guide plate substrate. The diameter and length of the guide column are set according to positioning requirements.

9. The method according to claim 1, characterized in that Step S5 further includes: S56: The patient information mark is automatically generated, and the input patient information is automatically generated in the selected area on the upper side of the guide plate substrate that does not contact the human body surface.

10. The method according to claim 1, characterized in that Step S5 further includes: S57: Automatically generate positioning holes, automatically identify the surface lead point in the patient's anatomical image, and generate positioning holes of a preset diameter on the three-dimensional model of the guide plate base plate with the lead point as the center through Boolean operation.

11. A brachytherapy implantation guide, characterized in that: Generated by the design method according to any one of claims 1 to 10, the brachytherapy implant guide comprises: Guide plate base plate: generated according to the patient's body contour and used for guide plate repositioning during treatment; Vaginal packing: generated based on pre-placed vaginal packing, used to open the patient's vagina to facilitate needle placement and to reposition the patient's vagina during treatment. The vaginal packing and the guide plate substrate are synthesized into a whole through Boolean operations; An implant needle channel is formed in the overall structure of the guide plate base and the vaginal packing through Boolean operations, and is used for the implant needle to pass through; Anti-rebound buckle: used to fix the implant needle to prevent the implant needle from rebounding when encountering resistance and sliding during treatment. The anti-rebound buckle includes a first rectangular model connected to the guide plate substrate and a second rectangular model detachably connected to the first rectangular model. The connecting surface of the first rectangular model and the second rectangular model is provided with a groove, and a silicone sheet or rubber sheet is provided in the groove. The needle-free side of the second rectangular model is provided with a slot and buckle that cooperate with the first rectangular model.

12. The brachytherapy implantation guide according to claim 11, wherein: Also includes: Patient information identification: used to identify patient information; Positioning hole: used to coincide with the lead mark on the patient's body surface to facilitate resetting; Median line: The median line of the template is designed according to the patient's clitoral position and vulvar midline to facilitate the doctor to confirm the position; Urethral opening: a hole in the urethra to prevent the catheter from being squeezed and to facilitate the doctor to observe the fit between the template and the vagina and body surface; Catheter groove: A groove that conforms to the shape of the catheter and is used to place and fix the catheter while preventing the template from squeezing the catheter; Fixing hole: used to cooperate with the fixing rod to fix the planting guide plate with the universal wheel of the rear-mounted bed; Guide column: Directed vertically downward from the human body, it is used to observe the reset status of the guide plate to determine whether the guide plate is rotated.

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