A method for manufacturing a bone model based on 3D printing technology

Abstract

The application discloses a kind of bone model manufacturing methods based on 3D printing technology, it is related to medical technology field, including, the multimodal image data of patient bone is collected, image segmentation and reconstruction are carried out, and the digital three-dimensional model of patient bone is generated;Mechanical optimization and material distribution adjustment are carried out to digital three-dimensional model using topological optimization algorithm, and bionic microstructure is designed, and the three-dimensional bone model optimized and bionic designed is output;The bone model for generating personalized mold is detected and qualified, and the prosthesis that is completely matched with patient bone is customized through mold personalized;Preoperative simulation and prosthesis implantation scheme design are carried out based on bone model, and the personalized prosthesis and surgical plan that adapt to patient bone are obtained;The topological optimization algorithm is used to maximize the structural stiffness and minimize the material usage, so that the bone model can better meet the biomechanical requirements of patients, and the bionic characteristics and mechanical properties of the model are enhanced through bionic microstructure design.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a method for producing a bone model based on 3D printing technology. Background Art

[0002] With the rapid development of medical technology, the creation of personalized medical models based on imaging data has become a key research area in modern medicine. Digitalization and three-dimensional reconstruction of bone models have been widely used in fields such as orthopedics, dentistry, and preoperative planning. Traditional methods rely primarily on the physician's experience and simple two-dimensional imaging, which makes it difficult to accurately reflect the complex three-dimensional structural characteristics of a patient's bones. However, with the widespread use of imaging devices such as CT and MRI, and advances in computer image processing algorithms, bone model creation methods combined with 3D printing technology have gradually become a research hotspot, making it possible to provide customized treatment plans for patients.

[0003] However, existing technologies still have some shortcomings in the process of bone model production. First, traditional image segmentation methods have limitations in resolution and accuracy, and cannot effectively deal with the complex geometric morphology and texture characteristics of bones, which may lead to insufficient model accuracy. Secondly, the mechanical optimization and material distribution design of bone models are usually relatively simple, and fail to fully consider individualized biomechanical needs, which may lead to deficiencies in the mechanical properties and bionic characteristics of the model. Finally, some technologies lack standardized processes in model surface treatment and subsequent testing, making it difficult to ensure model quality. Therefore, how to combine high-precision segmentation and reconstruction of multimodal imaging data, mechanical optimization and bionic design, and high-precision processing and detection technologies has become an urgent problem to be solved. Summary of the Invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a bone model production method based on 3D printing technology to solve the problem of how to prepare a high-precision bone model that meets personalized needs through multimodal imaging data segmentation and reconstruction, topology optimization and bionic design.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a method for producing a bone model based on 3D printing technology, which comprises collecting multimodal imaging data of a patient's bones, performing image segmentation and reconstruction, and generating a digital three-dimensional model of the patient's bones;

[0008] Use topology optimization algorithms to perform mechanical optimization and material distribution adjustments on the digital 3D model, design bionic microstructures, and output optimized and bionic-designed 3D bone models.

[0009] Input the optimized and biomimetic designed three-dimensional bone model data into the 3D printing device to form a solid model that matches the patient's bones;

[0010] The printed bone model is subjected to rough grinding and fine grinding to obtain a finely ground bone model;

[0011] The polished model is cleaned and dried, and then input into high-precision testing equipment for testing to generate a qualified bone model;

[0012] The qualified bone model is used to generate a personalized mold, and the mold is used to customize a prosthesis that fully matches the patient's bones;

[0013] Preoperative simulation and prosthesis implantation plan are designed based on the bone model to obtain a personalized prosthesis and surgical plan that suits the patient's bones.

[0014] As a preferred embodiment of the bone model production method based on 3D printing technology described in the present invention, the steps of collecting multimodal imaging data of the patient's bones, performing image segmentation and reconstruction, and generating a digital three-dimensional model of the patient's bones include the following steps:

[0015] Collect CT and MRI image data based on the patient's skeletal location and diagnostic needs;

[0016] Using a mutual information-based registration algorithm, the MRI image is aligned to the coordinate system of the CT image to generate registered multimodal image data;

[0017] Perform denoising, image enhancement and image standardization on the registered multimodal image data to obtain high-quality multimodal image data;

[0018] The deep learning-based U-Net model is used to extract features layer by layer from high-quality multimodal image data using an encoder. The feature maps are downsampled through convolution and maximum pooling operations to extract high-level semantic features.

[0019] The decoder performs an upsampling operation on the high-level semantic features in the downsampled feature map to obtain an upsampled feature map;

[0020] Perform jump connections between the downsampled feature map and the upsampled feature map to gradually restore the spatial resolution of the feature map and generate a segmentation probability map of the bone region;

[0021] According to the segmentation probability map of the bone area, the isosurface threshold is set, the three-dimensional image voxels are traversed, and the position where the gray value is equal to the threshold is found in each voxel, and the corresponding triangular mesh is generated;

[0022] The meshes within all voxels are merged to generate a digital 3D model of the patient's skeleton.

[0023] As a preferred embodiment of the bone model production method based on 3D printing technology described in the present invention, the method comprises the following steps: using a topology optimization algorithm to perform mechanical optimization and material distribution adjustment on the digital three-dimensional model, and designing a bionic microstructure, and outputting the optimized and bionic-designed three-dimensional bone model.

[0024] Importing a digitized 3D model of the patient's skeleton into topology optimization software;

[0025] Based on the patient's bone biomechanical requirements, the optimization goal is to maximize structural stiffness and minimize material usage, and volume constraints are imposed;

[0026] Setting boundary conditions and load locations on the digital 3D model of the patient's skeleton;

[0027] The density method is used to adjust the geometry and material distribution of the optimization objectives and constraints, as well as the boundary conditions and load positions, to obtain the optimized three-dimensional bone model, which is expressed as follows:

[0028]

[0029] Among them, ρ (k+1) (x) represents the material density distribution at position x at the k+1th iteration, ρ (k) (x) represents the material density distribution at position x at the kth iteration, k represents the iteration index, x represents the position, η represents the optimization step size, C represents the optimization objective of maximizing structural stiffness and minimizing material usage, and ρ(x) represents the material density distribution at position x;

[0030] Extracting geometric boundary and material distribution data from the optimized 3D bone model;

[0031] The bionic microstructure is designed based on a gradient porous structure method. The model is adjusted according to the porosity of the bone. The expression of the porosity distribution is:

[0032]

[0033] Where φ(x) represents the porosity at position x, φ0 represents the initial porosity, β represents the porosity variation, σ(ρ (k+1) (x)) represents the stress value of the material density distribution at position x at the k+1th iteration, σ max Indicates the maximum stress value in the bone model;

[0034] Embed the divided bionic microstructure into the geometric boundary of the optimized three-dimensional bone model;

[0035] The optimized three-dimensional bone model is mechanically verified using the finite element analysis method, and an optimized and biomimetic designed three-dimensional bone model is output.

[0036] As a preferred embodiment of the bone model production method based on 3D printing technology of the present invention, the optimized and biomimetic designed three-dimensional bone model data is input into the 3D printing device to form a solid model matching the patient's bones, which includes the following steps:

[0037] Conduct integrity checks on optimized and biomimetic designed 3D bone models;

[0038] After the integrity check, the 3D bone model is converted into a slice file dedicated to the 3D printing device and a printing path is generated;

[0039] Select the corresponding printing material and 3D printing process according to the biomechanical and biocompatibility requirements of the bone model;

[0040] Set the layer thickness, laser power and printing speed according to different printing materials and 3D printing processes;

[0041] Load the slice file into the 3D printing device for calibration;

[0042] After completing the setup and calibration, start the 3D printing device and print according to the generated printing path to form a solid model that matches the patient's bones.

[0043] As a preferred embodiment of the method for making a bone model based on 3D printing technology of the present invention, the printed bone model is subjected to rough grinding and fine grinding to obtain a finely ground bone model, which comprises the following steps:

[0044] Check the distribution of support structures, burr size, and degree of roughness on the surface of the solid model that matches the patient's anatomy, and select the required rough grinding tool based on the characteristics of the printing material;

[0045] Use high-speed rotary cutting tools to remove print support structures and rough grinding tools as needed to remove burrs;

[0046] Use a high-pressure air gun to remove the surface powder and particle residues of the roughly ground model to obtain a roughly ground solid model;

[0047] The surface of the rough-ground solid model is finely ground. Considering the effect of porosity on surface roughness, the roughness after grinding is obtained, and the expression is:

[0048] R a (t) = R a (0·φ(x))·e -k·t ;

[0049] Among them, R a (t) represents the roughness at time t after grinding, R a (0) represents the initial roughness before grinding, k represents the grinding efficiency coefficient, and t represents the time point;

[0050] The finely ground solid model is polished to obtain a finely polished bone model.

[0051] As a preferred embodiment of the method for producing a bone model based on 3D printing technology of the present invention, the polished model is cleaned and dried, and input into a high-precision detection device for detection. Generating a qualified bone model includes the following steps:

[0052] Prepare the cleaning solution using deionized water and neutral detergent, and set the cleaning parameters;

[0053] Place the finely polished bone model in a cleaning basket, start the ultrasonic cleaning machine, and clean the finely polished bone model according to the set parameters;

[0054] Use cleanroom-grade dust-free hot air drying equipment to dry the cleaned bone model;

[0055] The dried bone model is fixed on the workbench of the three-dimensional coordinate measuring machine, and a trigger probe is used to check point by point whether the size of the bone model surface meets the requirements;

[0056] Use white light interferometry to scan the surface area of ​​the bone model to see if the roughness meets the standard;

[0057] Use an industrial CT scanner to test the structural integrity of the bone model;

[0058] When one of the tests fails, repair it again until it passes the test;

[0059] When the size test, surface roughness test and structural integrity test are all qualified, a test report of a qualified bone model is generated.

[0060] As a preferred embodiment of the bone model production method based on 3D printing technology described in the present invention, the qualified bone model is used to generate a personalized mold, and the mold is used to customize a prosthesis that fully matches the patient's bones, including the following steps:

[0061] Import the qualified bone model into the mold design software and calibrate the coordinate system of the bone model according to the patient's anatomical imaging data;

[0062] Combine the patient's anatomical data with preoperative planning, analyze the bone surface morphology and prosthesis implantation requirements, determine the design parameters of the prosthesis, and select the mold type and mold material based on the complexity of the prosthesis;

[0063] Using the reverse engineering technology of the bone model, the mold cavity is generated according to the determined design parameters, mold type and mold material;

[0064] Perform dimensional inspection, assembly verification and functional testing on the mold cavity;

[0065] After passing the test, the prosthesis is manufactured to produce a prosthesis that is exactly matched to the patient's bones.

[0066] As a preferred embodiment of the bone model production method based on 3D printing technology of the present invention, the following steps are included: performing preoperative simulation and designing a prosthesis implantation plan based on the bone model to obtain a personalized prosthesis and surgical plan adapted to the patient's bones:

[0067] Obtain complete preoperative imaging data from the patient's CT and MRI imaging data;

[0068] Import the generated personalized prosthesis 3D model and the patient's bone model into the preoperative planning software, and align the prosthesis and bone model using reference points;

[0069] Determine the implant position and angle of the prosthesis based on the anatomical structure and prosthesis design requirements, and use preoperative planning software to adjust the angle and position;

[0070] Select the fixation method based on bone quality and prosthesis design, mark the fixation points on the prosthesis 3D model, and plan the screw implantation path and angle;

[0071] Use surgical simulation software to load the patient's bone model and prosthesis model for preoperative simulation and generate the surgical path and surgical plan for personalized prosthesis.

[0072] In a second aspect, the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, any step of the bone model production method based on 3D printing technology as described in the first aspect of the present invention is implemented.

[0073] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, any step of the bone model production method based on 3D printing technology as described in the first aspect of the present invention is implemented.

[0074] The beneficial effects of the present invention are as follows: through high-precision segmentation and three-dimensional reconstruction of multimodal imaging data, combined with topological optimization algorithms and bionic microstructure design, the precise production of digital bone models is achieved, and the personalization and functional adaptability of the models are significantly improved; in the image processing link, a deep learning-based segmentation algorithm is adopted to effectively improve the accuracy of bone area extraction, laying a solid foundation for the subsequent model construction; in the mechanical optimization link, the topological optimization algorithm is used to maximize the structural stiffness and minimize the material usage, so that the bone model can better meet the patient's biomechanical needs, and at the same time, the bionic characteristics and mechanical properties of the model are enhanced through bionic microstructure design; in the model surface treatment and detection stages, refined processing methods and strict detection standards are adopted to ensure the structural integrity and surface quality of the final model. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] 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 description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0076] Figure 1 This is a flow chart of the method for making a bone model based on 3D printing technology in Example 1.

[0077] Figure 2 Generate a schematic diagram for the qualified skeletal model in Example 1. DETAILED DESCRIPTION

[0078] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0079] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0080] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0081] Example 1, reference Figure 1 and Figure 2, which is the first embodiment of the present invention, provides a method for making a bone model based on 3D printing technology, comprising the following steps:

[0082] S1. Collect multimodal imaging data of the patient's bones, perform image segmentation and reconstruction, and generate a digital three-dimensional model of the patient's bones.

[0083] S1.1. Collect CT and MRI image data based on the patient's skeletal location and diagnostic needs.

[0084] Specifically, CT image acquisition provides high-resolution bone density information, which is suitable for hard tissue imaging and ensures sufficient resolution of bone microstructure.

[0085] MRI image acquisition provides rich details of soft tissue and bone marrow and is used for imaging the soft tissue-bone interface.

[0086] S1.2. Use a mutual information-based registration algorithm to align the MRI image to the coordinate system of the CT image to generate registered multimodal image data.

[0087] Specifically, mutual information is an indicator that measures the degree of information sharing between two images. After registration, the difference between the joint distribution of the grayscale values ​​of the two images and their independent distribution reaches the maximum, that is, the two images contain the most common information in the aligned state. Registration based on mutual information can handle the grayscale differences of multimodal images.

[0088] S1.3. Perform denoising, image enhancement, and image normalization on the registered multimodal image data to obtain high-quality multimodal image data.

[0089] Specifically, the denoising process uses a non-local means denoising method to reduce artifacts.

[0090] Image enhancement uses histogram equalization to enhance the contrast and edge clarity of bone edges.

[0091] Image normalization is to normalize all image voxels to zero mean and unit variance, so that the subsequent deep learning model can adapt to multimodal images.

[0092] S1.4. A U-Net model based on deep learning is used. The encoder is used to extract features layer by layer from high-quality multimodal imaging data. The feature map is downsampled through convolution and maximum pooling operations to extract high-level semantic features. The decoder upsamples the high-level semantic features in the downsampled feature map to obtain an upsampled feature map. The downsampled feature map is jump-connected to the upsampled feature map to gradually restore the spatial resolution of the feature map and generate a segmentation probability map for the bone region. The isosurface threshold is set according to the segmentation probability map of the bone region, and the three-dimensional image voxels are traversed. The position where the grayscale value is equal to the threshold is found in each voxel, and the corresponding triangular mesh is generated. The meshes in all voxels are merged to generate a digital three-dimensional model of the patient's bones.

[0093] Specifically, the encoder part introduces residual blocks to extract complex features. The residual blocks can alleviate the gradient vanishing problem and improve the training efficiency of deep networks.

[0094] The skip connection retains the detailed information of the bone edges and ensures the spatial consistency of the segmentation results.

[0095] S2. Use topology optimization algorithms to perform mechanical optimization and material distribution adjustments on the digital 3D model, design biomimetic microstructures, and output an optimized and biomimetic 3D bone model.

[0096] S2.1. Import the digital 3D model of the patient's skeleton into topology optimization software; set the optimization goal to maximize structural stiffness and minimize material usage based on the patient's skeletal biomechanical requirements, and apply volume constraints; set boundary conditions and load positions for the digital 3D model of the patient's skeleton.

[0097] Specifically, the fixed boundary condition simulates the fixation of bones at the joints or ligaments; the load condition sets external loads (such as weight distribution, dynamic motion loads, etc.) based on the patient's bone mechanics requirements. The load can be determined through patient gait analysis or mechanical test data.

[0098] S2.2. Using the density method, adjust the geometry and material distribution of the optimization objectives and constraints, as well as the boundary conditions and load locations, to obtain the optimized three-dimensional bone model, expressed as:

[0099]

[0100] Among them, ρ (k+1) (x) represents the material density distribution at position x at the k+1th iteration, ρ (k)(x) represents the material density distribution at position x at the kth iteration, k represents the iteration index, x represents the position, η represents the optimization step size, C represents the maximization of structural stiffness and minimization of material usage in the optimization objectives, and ρ(x) represents the material density distribution at position x.

[0101] S2.3. Extract geometric boundary and material distribution data from the adjusted geometry and material distribution. Design a biomimetic microstructure using a gradient porous structure-based approach. Adjust the model based on the porosity of bone. The porosity distribution is expressed as:

[0102]

[0103] Where φ(x) represents the porosity at position x, φ0 represents the initial porosity, β represents the porosity variation, σ(ρ (k+1) (x)) represents the stress value of the material density distribution at position x at the k+1th iteration, σ max Indicates the maximum stress value in the bone model;

[0104] The bionic microstructure after dividing the area is embedded into the geometric boundary of the optimized three-dimensional bone model.

[0105] Specifically, bionic microstructure design requires analysis of the structural characteristics of natural bone tissue. Natural bone tissue has a hierarchical porous structure and is both lightweight and high-strength. Bionic design needs to simulate the characteristics of trabeculae and compact bone. Trabeculae are internal porous structures with good compressive resistance and shock absorption capabilities, while compact bone is an external dense structure used to bear greater forces.

[0106] S2.4. Use finite element analysis to perform mechanical verification on the optimized three-dimensional bone model and output an optimized and biomimetic-designed three-dimensional bone model.

[0107] Specifically, the steps of finite element analysis are as follows:

[0108] The optimized three-dimensional bone model is exported to a format suitable for finite element analysis and meshed. For regular-shaped areas, hexahedral unit meshes are used; for complex surfaces or curved surfaces, tetrahedral unit meshes are used; fixed constraints or support conditions are set according to the mechanical design requirements of the bone model; actual loads are applied according to the usage scenario to simulate the stress conditions of the model under physiological conditions. If joint movement or impact force needs to be simulated, time-varying loads are applied; finite element static analysis is run to obtain the stress distribution diagram of the bone model and check the deformation of the bone model under load; if stress concentration areas are found in the model (such as pore edges or weak areas), their specific locations and stress values ​​are recorded to determine the cause of stress concentration and optimize the porosity distribution for the stress concentration areas; based on the corrected porosity distribution or structural parameters, the model is updated and finite element analysis is performed again, and adjustments are continued until the stress distribution of the model is uniform and there is no obvious stress concentration.

[0109] S3. Input the optimized and biomimetic designed three-dimensional bone model data into the 3D printing device to form a solid model that matches the patient's bones.

[0110] S3.1. Perform an integrity check on the optimized and biomimetic-designed three-dimensional bone model; convert the integrity-checked three-dimensional bone model into a slice file dedicated to the 3D printing device and generate a printing path.

[0111] Specifically, the integrity check includes mesh checking and normal vector correction.

[0112] Mesh Check: Verify that the triangle mesh in the STL file is complete (no holes, no overlapping faces).

[0113] For mesh problems found, you can use software such as MeshLab or Magics to automatically repair them.

[0114] Normal vector correction: Ensures that the normal vector of each triangle mesh points to the outside of the model. If the normal vector is incorrect, the printing device may not be able to distinguish between the interior and exterior areas.

[0115] S3.2. Select the appropriate printing material and 3D printing process based on the biomechanical and biocompatibility requirements of the bone model. Set the layer thickness, laser power, and printing speed according to the different printing materials and 3D printing processes. Load the slice file into the 3D printing device for calibration. After completing the setup and calibration, start the 3D printing device and print according to the generated printing path to form a solid model that matches the patient's bones.

[0116] Specifically, the printing materials include medical-grade metal powder (titanium alloy Ti-6Al-4V) and bioceramics (hydroxyapatite, HA).

[0117] The advantages of medical-grade metal powder are high strength, good corrosion resistance, and excellent biocompatibility. It is suitable for load-bearing bones (such as femur and acetabulum) and is used in scenarios where patients have high activity levels or high bone load-bearing requirements.

[0118] The advantages of bioceramics are that their chemical properties are close to those of natural bone tissue, they have strong ability to promote bone integration, and they are suitable for non-load-bearing bones or surface coatings. They are mainly used in bone defect repair or scenarios that require rapid bone integration.

[0119] In the 3D printing process, metal printing uses selective laser melting technology, which uses high-power laser to sinter metal powder layer by layer. Ceramic printing uses stereolithography or direct ceramic printing technology.

[0120] S4. Performing rough grinding and fine grinding on the surface of the printed bone model to obtain a finely ground bone model.

[0121] S4.1. Check the distribution of support structures, burr size, and degree of roughness on the surface of the solid model that matches the patient's anatomy, and select the required rough grinding tool based on the characteristics of the printing material.

[0122] Specifically, the tool selection for surface rough grinding is: if it is a metal model (such as titanium alloy): use a carbide rotary tool or a grinding wheel; if it is a ceramic model (such as hydroxyapatite): use a silicon carbide grinding wheel or a diamond grinding wheel.

[0123] S4.2. Use a high-speed rotary cutting tool to remove the printed support structure and use a rough grinding tool as needed to remove burrs. Use a high-pressure air gun to remove powder and particle residue from the surface of the rough-ground model to obtain a rough-ground solid model. Fine-grind the surface of the rough-ground solid model, taking into account the effect of porosity on surface roughness, to obtain the roughness after grinding, expressed as:

[0124] R a (t) = R a (0·φ(x))·e -k·t ;

[0125] Among them, R a (t) represents the roughness at time t after grinding, R a (0) represents the initial roughness before grinding, k represents the grinding efficiency coefficient, and t represents the time point;

[0126] The finely ground solid model is polished to obtain a finely polished bone model.

[0127] Specifically, the polishing process includes electrolytic polishing and mechanical polishing.

[0128] The principle of electrolytic polishing (for metal models) is to remove surface micro-protrusions through electrolysis to improve surface smoothness. The model is immersed in an electrolyte (commonly used a mixture of phosphoric acid and sulfuric acid in a ratio of 85%:15%), with the electrolysis voltage set at 5-10V, the current density at 10-50A / dm2, and the electrolysis time at 5-15min. The electrolysis effect can reduce the surface roughness to 0.5-1.0μm.

[0129] Mechanical polishing (for ceramic models) uses diamond polishing paste (particle size 1-3 μm). The specific operation is to apply the polishing paste to the surface of the model and use a high-speed rotating polishing wheel for processing. The speed is: 1000-3000 rpm, and the polishing time is: 10-20 minutes.

[0130] S5. The polished model is cleaned and dried, and then input into high-precision testing equipment for testing to generate a qualified bone model.

[0131] S5.1. Prepare the cleaning solution using deionized water and neutral detergent, and set the cleaning parameters.

[0132] Specifically, the cleaning liquid mainly uses deionized water (DI water) with an appropriate amount of neutral cleaning agent (such as a surfactant solution, with a recommended concentration of 1-2%). Its characteristics are that it does not corrode the surface of the model and can effectively suspend and remove residues.

[0133] Cleaning parameter settings include cleaning fluid temperature, ultrasonic power density, cleaning time, and liquid circulation.

[0134] Cleaning fluid temperature: controlled at 30-50°C to improve cleaning efficiency while avoiding damage to surface quality due to high temperature; ultrasonic power density: 10-20W / L to ensure uniform cleaning; cleaning time: 5-15 minutes, adjusted according to model complexity; liquid circulation: ensure that the cleaning fluid maintains fluidity during the cleaning process to prevent particles from re-attaching.

[0135] S5.2. Place the finely polished bone model in a cleaning basket, start the ultrasonic cleaning machine, and clean the finely polished bone model according to the set parameters.

[0136] Specifically, the ultrasonic cleaning process: Ultrasonic waves form tiny bubbles through the "cavitation effect", which effectively removes surface attachments. For bone models with complex structures (such as areas containing bionic microstructures), multiple cleaning steps can be added:

[0137] Step 1: Use a detergent solution to perform a rough wash to remove large particles.

[0138] Step 2: Use pure deionized water for fine cleaning to thoroughly remove detergent residues.

[0139] S5.3. Use cleanroom-grade dust-free hot air drying equipment to dry the cleaned bone model; fix the dried bone model on the workbench of the three-dimensional coordinate measuring machine, and use a trigger probe to check point by point whether the size of the bone model surface meets the requirements; use a white light interferometer to scan the surface area of ​​the bone model to see if the roughness meets the standard; use an industrial CT scanner to perform structural integrity testing on the bone model; if one test fails, repair it again until it passes the test; when the size test, surface roughness test and structural integrity test are all qualified, generate a qualified bone model test report.

[0140] Specifically, the drying operation includes model placement, temperature setting, drying time and cooling treatment.

[0141] Furthermore, model placement: Place the cleaned bone model on the drying equipment tray, maintain the model spacing, and ensure smooth circulation of hot air.

[0142] Temperature setting: Set the device temperature to 40°C. For special materials such as ceramics, it can be set to 60°C.

[0143] Drying time: The running time is 30 to 60 minutes to ensure that the water is completely evaporated.

[0144] Cooling process: After drying, cool the model to room temperature in a dust-free environment.

[0145] S6. The qualified bone model is used to generate a personalized mold, and the mold is used to customize a prosthesis that perfectly matches the patient's bones.

[0146] S6.1. Import the qualified bone model into the mold design software and calibrate the coordinate system of the bone model according to the patient's anatomical imaging data; combine the patient's anatomical data with the preoperative plan, analyze the bone surface morphology and prosthesis implantation requirements, determine the design parameters of the prosthesis, and select the mold type and mold material according to the complexity of the prosthesis; use the reverse engineering technology of the bone model to generate the mold cavity according to the determined design parameters, mold type and mold material; perform dimensional inspection, assembly verification and functional testing on the mold cavity; after passing the test, manufacture the prosthesis to generate a prosthesis that fully matches the patient's bones.

[0147] Specifically, the specific operations of mold cavity design are:

[0148] The reverse engineering technology of the bone model is used to generate the mold cavity, which is completely matched with the patient's bone surface; through the Boolean subtraction function in the software, the bone model (positive mold) is used to subtract the mold blank (negative mold) to generate a precise inner cavity; the error range between the inner cavity and the bone model is set to 0.02~0.05mm to ensure high-precision fit between the prosthesis and the bone; the edges of the mold cavity are filleted to avoid sharp edges that may cause defects in the prosthesis manufacturing.

[0149] S7. Perform preoperative simulation and design of prosthesis implantation plans based on the skeletal model to obtain a personalized prosthesis and surgical plan that fits the patient's anatomy.

[0150] S7.1. Acquire complete preoperative imaging data from the patient's CT and MRI imaging data; import the generated personalized prosthesis 3D model and the patient's skeletal model into the preoperative planning software, and align the prosthesis and skeletal model using reference points; determine the implantation position and angle of the prosthesis based on the anatomical structure and prosthesis design requirements, and use the preoperative planning software to adjust the angle and position; select the fixation method based on the bone quality and prosthesis design, mark the fixation points in the prosthesis 3D model, and plan the screw implantation path and angle; use the surgical simulation software to load the patient's skeletal model and prosthesis model, perform preoperative simulation, and generate the surgical path and surgical plan for the personalized prosthesis.

[0151] Specifically, the implantation position and angle of the prosthesis are determined according to the anatomical structure and prosthesis design requirements.

[0152] For hip prostheses, the insertion angle of the femoral stem (CCD angle) and the internal rotation angle of the prosthesis need to be planned.

[0153] For knee prostheses, the alignment angle between the prosthesis and the tibial plateau needs to be planned.

[0154] Choose the appropriate fixation method based on bone quality and prosthesis design:

[0155] Bone cement fixation: suitable for patients with poor bone quality.

[0156] Cementless fixation: bone ingrowth is achieved through the porous structure of the prosthesis surface.

[0157] Screw fixation: Additional screw holes are designed for prostheses with complex structures.

[0158] This embodiment also provides a computer device, which is suitable for the case of a bone model production method based on 3D printing technology, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement the bone model production method based on 3D printing technology proposed in the above embodiment.

[0159] The computer device may be a terminal, comprising a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0160] This embodiment also provides a storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for producing a bone model based on 3D printing technology as proposed in the above embodiment; the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0161] In summary, the present invention realizes the precise production of digital bone models through high-precision segmentation and three-dimensional reconstruction of multimodal imaging data, combined with topological optimization algorithms and bionic microstructure design, significantly improving the model's personalization and functional adaptability; in the image processing link, a deep learning-based segmentation algorithm is adopted to effectively improve the accuracy of bone area extraction, laying a solid foundation for the subsequent model construction; in the mechanical optimization link, the topological optimization algorithm is used to maximize the structural stiffness and minimize the material usage, so that the bone model can better meet the patient's biomechanical needs, and at the same time, the bionic characteristics and mechanical properties of the model are enhanced through bionic microstructure design; in the model surface treatment and detection stages, refined processing methods and strict detection standards are adopted to ensure the structural integrity and surface quality of the final model.

[0162] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for producing a bone model based on 3D printing technology, characterized in that: include, The following steps are involved in collecting multimodal imaging data of the patient's bones, performing image segmentation and reconstruction, and generating a digital three-dimensional model of the patient's bones: Collect CT and MRI image data based on the patient's skeletal location and diagnostic needs; Using a mutual information-based registration algorithm, the MRI image is aligned to the coordinate system of the CT image to generate registered multimodal image data; Perform denoising, image enhancement and image standardization on the registered multimodal image data to obtain high-quality multimodal image data; The deep learning-based U-Net model is used to extract features layer by layer from high-quality multimodal image data using an encoder. The feature maps are downsampled through convolution and maximum pooling operations to extract high-level semantic features. The decoder performs an upsampling operation on the high-level semantic features in the downsampled feature map to obtain an upsampled feature map; Perform jump connections between the downsampled feature map and the upsampled feature map to gradually restore the spatial resolution of the feature map and generate a segmentation probability map of the bone region; According to the segmentation probability map of the bone area, the isosurface threshold is set, the three-dimensional image voxels are traversed, and the position where the gray value is equal to the threshold is found in each voxel, and the corresponding triangular mesh is generated; Merge the meshes within all voxels to generate a digital three-dimensional model of the patient's skeleton; Use topology optimization algorithms to perform mechanical optimization and material distribution adjustments on the digital 3D model, design bionic microstructures, and output optimized and bionic-designed 3D bone models. Input the optimized and biomimetic designed three-dimensional bone model data into the 3D printing device to form a solid model that matches the patient's bones; The printed bone model is subjected to rough grinding and fine grinding to obtain a finely ground bone model; The polished model is cleaned and dried, and then input into high-precision testing equipment for testing to generate a qualified bone model; The qualified bone model is used to generate a personalized mold, and the mold is used to customize a prosthesis that fully matches the patient's bones; Preoperative simulation and prosthesis implantation plan are designed based on the bone model to obtain a personalized prosthesis and surgical plan that suits the patient's bones.

2. The method for making a skeletal model based on 3D printing technology according to claim 1, wherein: Using topology optimization algorithms to perform mechanical optimization and material distribution adjustment on the digital 3D model, and designing bionic microstructures, the output of the optimized and bionic designed 3D bone model includes the following steps: Importing a digitized 3D model of the patient's skeleton into topology optimization software; Based on the patient's bone biomechanical requirements, the optimization goal is to maximize structural stiffness and minimize material usage, and volume constraints are imposed; Setting boundary conditions and load locations on the digital 3D model of the patient's skeleton; The density method is used to adjust the geometry and material distribution of the optimization objectives and constraints, as well as the boundary conditions and load positions, to obtain the optimized three-dimensional bone model. The expression for the updated density distribution is: ； in, Indicates the position at the K+1th iteration The material density distribution, Indicates the The position at the iteration The material density distribution, Represents the iteration index, Indicates location, represents the optimization step size, Indicates the optimization objective of maximizing structural stiffness and minimizing material usage, Indicates the location Material density distribution at Extracting geometric boundary and material distribution data from the optimized 3D bone model; The bionic microstructure is designed based on a gradient porous structure method. The model is adjusted according to the porosity of the bone. The expression of the porosity distribution is: ； in, Indicates location The porosity, represents the initial porosity, represents the porosity variation, Indicates the position at the K+1th iteration The stress value of the material density distribution, Indicates the maximum stress value in the bone model; Embed the divided bionic microstructure into the geometric boundary of the optimized three-dimensional bone model; The optimized three-dimensional bone model is mechanically verified using the finite element analysis method, and an optimized and biomimetic designed three-dimensional bone model is output.

3. The method for making a skeletal model based on 3D printing technology according to claim 2, wherein: Inputting optimized and biomimetic designed three-dimensional bone model data into the 3D printing device to form a solid model that matches the patient's bones includes the following steps: Conduct integrity checks on optimized and biomimetic designed 3D bone models; After the integrity check, the 3D bone model is converted into a slice file dedicated to the 3D printing device and a printing path is generated; Select the corresponding printing material and 3D printing process according to the biomechanical and biocompatibility requirements of the bone model; Set the layer thickness, laser power and printing speed according to different printing materials and 3D printing processes; Load the slice file into the 3D printing device for calibration; After completing the setup and calibration, start the 3D printing device and print according to the generated printing path to form a solid model that matches the patient's bones.

4. The method for making a skeletal model based on 3D printing technology according to claim 3, wherein: The printed bone model is subjected to rough grinding and fine grinding to obtain a finely ground bone model, which includes the following steps: Check the distribution of support structures, burr size, and degree of roughness on the surface of the solid model that matches the patient's anatomy, and select the required rough grinding tool based on the characteristics of the printing material; Use high-speed rotary cutting tools to remove print support structures and rough grinding tools as needed to remove burrs; Use a high-pressure air gun to remove the surface powder and particle residues of the roughly ground model to obtain a roughly ground solid model; The surface of the rough-ground solid model is finely ground. Considering the effect of porosity on surface roughness, the roughness after grinding is obtained, and the expression is: ； in, Indicates the time after grinding The roughness, Indicates the initial roughness before grinding, represents the grinding efficiency coefficient, Indicates a point in time; The finely ground solid model is polished to obtain a finely polished bone model.

5. The method for making a skeletal model based on 3D printing technology according to claim 4, wherein: The polished model is cleaned and dried, and then input into high-precision testing equipment for testing. Generating a qualified bone model includes the following steps: Prepare the cleaning solution using deionized water and neutral detergent, and set the cleaning parameters; Place the finely polished bone model in a cleaning basket, start the ultrasonic cleaning machine, and clean the finely polished bone model according to the set parameters; Use cleanroom-grade dust-free hot air drying equipment to dry the cleaned bone model; The dried bone model is fixed on the workbench of the three-dimensional coordinate measuring machine, and a trigger probe is used to check point by point whether the size of the bone model surface meets the requirements; Use white light interferometry to scan the surface area of ​​the bone model to see if the roughness meets the standard; Use an industrial CT scanner to test the structural integrity of the bone model; When one of the tests fails, repair it again until it passes the test; When the size test, surface roughness test and structural integrity test are all qualified, a test report of a qualified bone model is generated.

6. The method for making a skeletal model based on 3D printing technology according to claim 5, wherein: The qualified bone model is used to generate a personalized mold. The following steps are involved in customizing a prosthesis that fully matches the patient's bones through the mold: Import the qualified bone model into the mold design software and calibrate the coordinate system of the bone model according to the patient's anatomical imaging data; Combine the patient's anatomical data with preoperative planning, analyze the bone surface morphology and prosthesis implantation requirements, determine the design parameters of the prosthesis, and select the mold type and mold material based on the complexity of the prosthesis; Using the reverse engineering technology of the bone model, the mold cavity is generated according to the determined design parameters, mold type and mold material; Perform dimensional inspection, assembly verification and functional testing on the mold cavity; After passing the test, the prosthesis is manufactured to produce a prosthesis that is exactly matched to the patient's bones.

7. The method for making a skeletal model based on 3D printing technology according to claim 6, wherein: The following steps are involved in preoperative simulation and prosthesis implantation plan design based on the bone model to obtain a personalized prosthesis and surgical plan that fits the patient's bones: Obtain complete preoperative imaging data from the patient's CT and MRI imaging data; Import the generated personalized prosthesis 3D model and the patient's bone model into the preoperative planning software, and align the prosthesis and bone model using reference points; Determine the implant position and angle of the prosthesis based on the anatomical structure and prosthesis design requirements, and use preoperative planning software to adjust the angle and position; Select the fixation method based on bone quality and prosthesis design, mark the fixation points on the prosthesis 3D model, and plan the screw implantation path and angle; Use surgical simulation software to load the patient's bone model and prosthesis model for preoperative simulation and generate the surgical path and surgical plan for personalized prosthesis.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the skeletal model production method based on 3D printing technology described in any one of claims 1 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the skeletal model production method based on 3D printing technology described in any one of claims 1 to 7 are implemented.

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