Radiation protection reference man digital model parameterization reconstruction method

Abstract

The application discloses a kind of parameterization reconstruction methods for reference person digital model for radiation protection, belong to nuclear radiation protection technical field, its method includes following steps: S1.Analysis target reference person physiological parameter and anatomical parameter, S2.Analysis the difference between target reference person and standard reference person model, S3.Parameterization adjustment is carried out to the internal organ of standard reference person model, S4.According to the modification result of internal organ, whole body tissue is constructed, S5.Model weight adjustment is carried out, and target reference person model is generated;The application improves the applicability and representativeness of model in diversified crowd dose evaluation, significantly improves the construction efficiency of model, in addition, the method of the application can improve dose evaluation accuracy and the pertinence of protection measures.

Description

Technical Field

[0001] This invention relates to the field of nuclear radiation protection technology, and in particular to a method for parametric reconstruction of a reference human digital model for radiation protection. Background Technology

[0002] Human body models emerged to meet the research needs of nuclear radiation protection. Their development has progressed from simple geometric models and mathematical models to voxel models and finally to surface-based models. With increasing model refinement, modern computer-generated human body models can not only accurately describe the overall morphology of the human body but also reflect in detail the shape, structure, and relative positions of major internal organs, providing a solid theoretical foundation for radiation dose assessment, medical imaging, and clinical simulation. However, with the increase in model accuracy and complexity, the difficulty of their construction, calibration, and maintenance has also significantly increased.

[0003] A reference human model is a computer-generated human body model based on statistical data. Its anatomical structure is relatively universal and can represent the general anatomical structure of a specific population. In radiation protection, the reference human model is a core tool for dose calculation and the development of protection standards. Using Monte Carlo simulation software to calculate the dose of human organs, the radiation absorption and distribution of different parts of the body can be obtained, providing theoretical basis and data support for radiation protection, risk assessment, and standard development.

[0004] However, due to significant differences in organ quality and body proportions among different population groups—the difference between the population data used to construct a specific reference model and the target population data—human model construction is often limited by the acquisition of whole-body medical images and image segmentation techniques, making the process complex and difficult to widely apply.

[0005] Traditional dose assessment methods often use a standardized reference model for Monte Carlo simulations, which fail to reflect differences in gender, age, body type, and other factors, and thus cannot fully reflect the actual situation of the target population. These differences may lead to biases in dose simulation results, thereby affecting the accuracy and applicability of protection standards.

[0006] In addition, traditional methods often require building digital models of different groups of people from scratch, which is cumbersome and inefficient. Summary of the Invention

[0007] The purpose of this invention is to provide a parametric reconstruction method for a reference human digital model for radiation protection, so as to solve the above-mentioned problems.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A parameterized reconstruction method of a reference person digital model for radiation protection, comprising the following steps:

[0010] S1. Analyzing physiological parameters and anatomical parameters of a target reference person;

[0011] S2. Analyzing the differences between the target reference person and a standard reference person model;

[0012] S3. Parameterized adjustment of internal organs of the standard reference person model;

[0013] S4. Constructing whole body tissues according to the modification results of the internal organs;

[0014] S5. Model weight adjustment to generate a target reference person model.

[0015] Due to the differences between the population data used when a certain specific reference person is constructed and the target population data, the traditional dose evaluation method often uses a unified standard reference person model, which is difficult to reflect the differences of different populations in terms of gender, age, body type, etc. The present application introduces key physiological parameters (such as height, weight, organ mass) for parameterized adjustment, so that the model can adapt to the statistical characteristics of different populations, thereby improving the applicability and representativeness of the model in diversified population dose evaluation.

[0016] In addition, in order to solve the problem that the traditional method often needs to start from scratch to construct digital models of different populations, the process is tedious and inefficient, the present application uses a parameterized method to make the adjustment process of the model more automated and systematic, only a small number of parameters need to be changed, and the structure adjustment can be quickly completed, which significantly improves the modeling efficiency, especially suitable for scenarios of batch generation or iterative updating of models. The method of the present application is to modify the already established reference person model, while the traditional method establishes a new reference person model that meets the parameters of the target population from scratch, which has much more work than modifying the model, so the method of the present application significantly improves the modeling efficiency. In addition, the method of the present application can improve the accuracy of dose evaluation and the pertinence of protection measures.

[0017] As a preferred technical solution:

[0018] Step S1 includes:

[0019] S11. Collecting physiological data and human anatomical data of the target population, the physiological data and human anatomical data including gender, age, height, weight, organ volume, and organ mass;

[0020] S12. Extract parameters representing the characteristics of the population from the collected data as the physiological and anatomical parameter benchmarks of the target reference person. Among them, the parameters representing the characteristics of the population refer to the physiological data and human anatomical data mentioned in S11, including gender, age, height, weight, organ volume, organ mass, and statistical values of the anatomical, physiological and other parameters of a certain specific population after scientific analysis (such as taking the average or median) to form a data set describing the physiological characteristics and anatomical characteristics of the population. The reference person typifies a certain specific population and is used to represent the population so that different individuals in the population can be treated uniformly on the same biological basis. That is, a data set is obtained which can represent the physiological data and anatomical data of the target population.

[0021] As a preferred technical solution:

[0022] Step S2 includes:

[0023] S21. The model to be modified is a structurally complete surface element reference person model;

[0024] S22. Analyze the differences in height, weight and internal organ mass between the target reference person and the standard reference person model;

[0025] S23. Calculate the height adjustment factor, weight adjustment factor and organ scaling factor of the model based on the differences obtained in S22 to provide a basis for subsequent parameterization modification.

[0026] Among them, the "model to be modified" in S21 refers to the standard reference person model, and the model to be constructed, i.e. the target reference person model, is modified according to the standard reference person model.

[0027] As a further preferred technical solution:

[0028] In step S23, the height adjustment factor is the height adjustment factor in the z-axis, and its calculation formula is:

[0029] ,

[0030] Among them, is the height adjustment factor, is the height of the target reference person, is the height of the standard reference person;

[0031] The weight adjustment factor is the weight adjustment factor in the x, y plane, and its calculation formula is:

[0032] ,

[0033] Among them, is the weight adjustment factor, is the lean body mass of the target reference person, The standard reference person's lean body mass;

[0034] After determining the height and weight adjustment factors, the organs in the model need to be scaled to match the target reference person model in terms of organ mass differences.

[0035] The scaling of internal organs in the human body uses a three-axis proportional scaling method, which simultaneously scales proportionally in the x, y, and z directions. This scaling method ensures that the shape of the organ remains unchanged. The organ scaling factor calculation formula is:

[0036] ,

[0037] wherein, is the organ scaling factor, is the mass of a certain internal organ of the target reference person, is the mass of a certain internal organ of the standard reference person.

[0038] As a further preferred technical solution:

[0039] The calculation formulas for the lean body mass of the target reference person and the standard reference person both use the Boer formula and are gender-specific. The calculation formulas for the lean body mass of the male target reference person and the standard reference person are:

[0040] ,

[0041] The calculation formulas for the lean body mass of the female target reference person and the standard reference person are:

[0042] ,

[0043] wherein M is the body weight in kg and H is the height in cm.

[0044] As a preferred technical solution:

[0045] Step S3 includes:

[0046] S31. Convert the standard reference person's surface element model into a triangular mesh surface element model, separate the main internal organs in the reference person model, and independently adjust the size and optimize the spatial position of the separated organs.

[0047] S32. According to the height adjustment factor and the weight adjustment factor obtained in step S2, preliminarily parameterize and adjust all internal organs.

[0048] S33. After preliminary adjustment, the internal organs are scaled proportionally in three axes according to the organ scaling factor obtained in step S2, so that their mass conforms to the target reference person parameters.

[0049] S34. Position optimization is performed on the adjusted organs to avoid geometric overlap between organs and ensure anatomical reasonableness and spatial coordination.

[0050] As a preferred technical solution:

[0051] In step S4, the whole body tissues include lymph nodes, muscles, residual soft tissues, and skin.

[0052] Step S4 includes:

[0053] S41. According to the adjusted organ structure, lymph nodes are generated in the main distribution area of the lymph nodes to avoid overlap with surrounding organs.

[0054] S42. According to the height adjustment factor and the weight adjustment factor obtained in step S2, the whole body covering tissues including muscles, residual soft tissues, and skin are adjusted to conform to the geometric size of the target reference person.

[0055] S43. Geometric processing is sequentially performed on the muscle, residual soft tissue, and skin layers to eliminate overlapping areas between tissues and form a clear and coordinated body structure.

[0056] As a preferred technical solution,

[0057] In S43, the geometric processing method includes Boolean operation.

[0058] As a preferred technical solution:

[0059] Step S5 includes:

[0060] S51. Check whether the weight of the constructed model meets the target parameters. If not, adjust the model, and the specific adjustment method is as follows:

[0061] According to the weight of the target reference person, fine-tune the thickness of the muscle tissue and residual soft tissue of the standard reference person model modified in the preceding steps to meet the target reference person weight parameter.

[0062] It should be noted that the standard reference person model needs to be modified, and the target reference person is still in the construction process, and the target reference person is only a series of parameters.

[0063] S52. Output the modified model as a digital reference person model suitable for a specific population for direct use in subsequent dose simulation or radiation protection research.

[0064] The application adjusts the model by introducing key physiological parameters (such as height, weight, organ mass) to make the model adapt to the statistical characteristics of different populations, thereby improving the applicability and representativeness of the model in dose evaluation of diversified populations.

[0065] Among them, steps S2 and S3 are important application points of the present application. Among them, the prior art such as CN111008461A, CN118553399A, etc. directly constructs a human body model according to the parameters of the target human body, without analyzing the differences between the two populations, and the present application analyzes the differences between the two models in step S2 and quantifies the differences between the models to form parameters, i.e. a series of scaling factors, for subsequent model modification; step S2 is the preparation work for model reconstruction, providing modification parameters for subsequent model modification.

[0066] Through the quantified differences in step S2, the physiological differences between the two populations can be intuitively reflected, and the model modification focus can be highlighted. At the same time, the size of the scaling factor can guide researchers to analyze the direction of radiation dose simulation accuracy, such as the difference in height / weight leading to the difference in whole body dose, and the difference in organ mass being too large to cause the dose difference of the organ, surrounding organs, or even the whole body.

[0067] Step S3 performs parameterized modification of internal organs, and the main parameters come from the organ scaling factor in step S2; the prior art such as CN115797313A, CN118553399A, etc. is to modify the model for posture adjustment, and does not modify the internal organs of the whole model to deform it into a reference human model that conforms to the parameters of other populations.

[0068] Through step S3 of the present application, a general adjustment strategy and scaling logic are constructed based on the parameterized design concept, which does not depend on specific model structure or specific population data. In the future, if a new statistical population needs to be adapted, only the model scaling factor needs to be recalculated, without the need to redesign the entire method framework. The method has good adaptability and scalability.

[0069] Compared with the prior art, the present application has the advantages that the present application improves the applicability and representativeness of the model in dose evaluation of diversified populations, significantly improves the construction efficiency of the model, and in addition, the method of the present application can improve the dose evaluation accuracy and the pertinence of protection measures. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 is a flowchart of the construction method of the present application;

[0071] Figure 2 is a diagram of the internal organs of the modified reference human;

[0072] Figure 3A whole body tissue semi-profile of a target reference person model. DETAILED DESCRIPTION

[0073] The application will be further described in conjunction with the embodiments.

[0074] Embodiment 1

[0075] Reference Figure 1 A parameterization reconstruction method of a reference person digital model for radiation protection, comprising the following steps:

[0076] S1. Analyzing the physiological parameters and anatomical parameters of the target reference person:

[0077] S11. Collecting physiological data and human anatomical data of the target population, including but not limited to gender, age, height, weight, organ volume, organ mass, etc.; the data sources can be population physical database, CT or MRI anatomical image analysis results and phantom database, etc.;

[0078] S12. Extracting parameters representing the characteristics of the population from the collected data as the physiological and anatomical parameter benchmarks of the target reference person;

[0079] Specifically, in this embodiment, the data in the GBZ / T200 “Reference Person for Radiation Protection” standard is used as the physiological parameters and anatomical parameters of the target reference person.

[0080] S2. Analyzing the differences between the target reference person and the standard reference person model:

[0081] In this embodiment, the standard reference person model used is the adult mesh-type reference computational phantom (MRCP) published by the International Commission on Radiological Protection (ICRP).

[0082] Further, in this embodiment, the standard reference person model used is a male MRCP reference person model;

[0083] The differences between the target reference person parameters and the standard reference person model parameters are compared, mainly analyzing the differences in height, weight and internal organ mass of the human body between the two. Based on these differences, the scaling factors of the model are calculated, including height adjustment factor, weight adjustment factor and organ scaling factor, which provide the basis for subsequent parameterization modification;

[0084] The height difference is determined by calculating the ratio of the height of the target reference person to the height of the standard reference person. The height adjustment factor on the z-axis is calculated as follows:

[0085] ,

[0086] wherein, is the height adjustment factor, The height of the target reference person, The height of the standard reference person.

[0087] The weight difference is determined by calculating the ratio of the weight of the target reference person model to the weight of the standard reference person model, to obtain a weight adjustment factor in the x, y plane:

[0088] ,

[0089] wherein, is the weight adjustment factor, is the lean body mass of the target reference person, is the lean body mass of the standard reference person.

[0090] The calculation formula of the lean body mass of the target reference person and the lean body mass of the standard reference person both adopts the Boer formula, and is gender-differentiated:

[0091] For the lean body mass of the target reference person and the lean body mass of the standard reference person:

[0092] ,

[0093] The calculation formula of the lean body mass of the target reference person and the lean body mass of the standard reference person is:

[0094] ,

[0095] wherein, M is the weight (kg), and H is the height (cm).

[0096] After the preliminary adjustment of the height and the weight is completed, the difference analysis module next further adjusts the internal organs of the human body. In view of the internal organ mass difference of the target reference person model, each organ in the model is subjected to three-axis scaling processing, so that the mass of the organ is matched with the target reference person model. The scaling of the internal organs of the human body adopts a three-axis proportional scaling method, that is, proportional scaling is simultaneously performed in the x, y and z directions, and this scaling method can ensure that the morphology of the organ is unchanged;

[0097] ,

[0098] wherein, is the organ scaling factor, is the mass of a certain internal organ of the target reference person, is the mass of a certain internal organ of the standard reference person;

[0099] Specifically, in the embodiments, the weight and the height of the target reference person composed of the data in the GBZ / T200 “Reference Person for Radiation Protection” standard and the MRCP model published by the ICRP as the standard reference person are as shown in Table 1:

[0100] Table 1 Height and weight of target reference person and standard reference person

[0101] ,

[0102] The height adjustment factor is 0.965 and the weight adjustment factor is 0.966 calculated according to the data in Table 1;

[0103] The organ scaling factor calculation results of part of the tissue organs are shown in Table 2:

[0104] Table 2 Organ scaling factor calculation results of part of the tissue organs

[0105] ,

[0106] S3. Parameterized modification of internal organs of the standard reference person model:

[0107] First, import the MRCP model into Rhino8, and convert the model into a triangular mesh surface model using the mesh processing module in Rhino8.

[0108] Use the Grasshopper plug-in of Rhion8 to separate the internal organs in the reference person model. The separated organs can be independently adjusted in size and optimized in spatial position.

[0109] Further, import the height adjustment factor and weight adjustment factor obtained in step S2 into Grasshopper, and use the scaling module in Grasshopper to preliminarily parameterize and adjust all internal organs;

[0110] The height adjustment factor is applied to the z-axis scaling of the model, and the weight adjustment factor is applied to the x-axis and y-axis scaling of the model.

[0111] Import the organ scaling factor obtained in step S2 into Grasshopper, and then use the scaling module in Grasshopper to perform three-axis proportional scaling on the separated internal organs, so that their mass conforms to the target reference person parameters;

[0112] Use the mesh collision detection module in Grasshopper to optimize the position of the adjusted organs, avoid geometric overlap between organs, and ensure the reasonableness and spatial coordination of the anatomical structure. The modified internal tissue organ structure of the reference person is shown in Figure 2 .

[0113] S4. Reconstruct the whole body tissue according to the modification results of the internal organs:

[0114] In this embodiment, the whole body tissues include lymph nodes, muscles, residual soft tissues and skin; wherein the residual soft tissues are a fictitious human tissue, which is used to represent the non-main organ soft tissues such as fat, blood vessels, nerves and the like that are difficult to be described separately in modeling, and these tissues have a smaller role in radiation dose evaluation but cannot be ignored in the overall mass composition.

[0115] Specifically, the whole body tissues are constructed in the following manner:

[0116] The lymph nodes are generated in Grasshopper according to the internal organ structure that has been completed parameterized adjustment, and the lymph nodes are generated in the main distribution area of the lymph nodes, and the geometric algorithm in Grasshopper is used to ensure that the generated lymph nodes do not overlap with adjacent organs in space;

[0117] The main distribution area of the lymph nodes includes the neck, underarm, chest, groin area and limbs;

[0118] The height adjustment factor and the weight adjustment factor obtained in step S2 are imported into Grasshopper, and the whole body covering tissues (muscles, residual soft tissues and skin) are adjusted to conform to the geometric size of the target reference person;

[0119] The height adjustment factor is applied to the z-axis scaling of the model, and the weight adjustment factor is applied to the x-axis and y-axis scaling of the model.

[0120] The muscle, residual soft tissue and skin layers are sequentially subjected to Boolean operation and other geometric processing methods to eliminate the overlapping areas between the tissues, and a clear and coordinated body structure is formed.

[0121] S5. Model weight adjustment is performed to generate a target reference person model:

[0122] After the construction of the internal organs and the whole body tissues is completed, in order to ensure that the weight of the final model matches the target reference person, the whole body covering tissues of the model need to be fine-tuned;

[0123] Specifically, in the Grasshopper modeling environment, the thickness of the muscle tissue and the residual soft tissue is adjusted to increase or decrease the weight of the reference person;

[0124] After the overall model adjustment is completed, the internal organs modified by parameterization, the lymph nodes, muscles, residual soft tissues and skin and the like will form a reasonable structure grid model, and the whole body tissue half-section effect is as shown in Figure 3 ;

[0125] An identifiable digital serial number index and name identification are established for each organ / tissue grid in the model, so as to meet the subsequent dose simulation or model modification requirements.

[0126] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for parameterized reconstruction of a reference human digital model for radiation protection, characterized in that, The method comprises the following steps: S1. Analyzing physiological parameters and anatomical parameters of a target reference person; S2. Analyzing differences between the target reference person and a standard reference person model; S3. Parametrically adjusting internal organs of the standard reference person model; S4. Constructing a whole body tissue according to the modification results of the internal organs; S5. Performing model weight adjustment to generate a target reference person model; Step S1 comprises: S11. Collecting physiological data and human anatomical data of a target population, the physiological data and human anatomical data comprising gender, age, height, weight, organ volume, and organ mass; S12. Extracting parameters representing characteristics of the population from the collected data as physiological and anatomical parameter benchmarks of the target reference person; Step S2 comprises: S21. The model to be modified is a structured surface element reference person model; S22. Analyzing differences in height, weight, and internal organ mass between the target reference person and the standard reference person model; S23. Calculating a height adjustment factor, a weight adjustment factor, and an organ scaling factor of the model based on the differences obtained in S22 to provide a basis for subsequent parametric modification; In step S23, the height adjustment factor is a height adjustment factor on the z-axis, and the calculation formula is: ， wherein, is a height adjustment factor, is a target reference person height, is a standard reference person height; The weight adjustment factor is a weight adjustment factor on the x and y planes, and the calculation formula is: ， wherein, is a body weight adjustment factor, is a target reference person lean body weight, is a standard reference person lean body weight; The scaling of the internal organs of the human body adopts a three-axis equal scaling method, which simultaneously performs equal scaling in the x, y, and z directions. This scaling method can ensure that the shape of the organ remains unchanged, and the calculation formula of the organ scaling factor is: ， wherein, is an organ scaling factor, is the mass of a certain internal organ of the target reference person, is the mass of a certain internal organ of the standard reference person.

2. The method of claim 1, wherein, The calculation formula of the lean body mass of the target reference person and the standard reference person adopts the Boer formula and is gender-differentiated; wherein the calculation formula of the lean body mass of the male target reference person and the standard reference person is: ， The calculation formula of the lean body mass of the female target reference person and the standard reference person is: ， Wherein, M is the weight, the unit is kg; H is the height, the unit is cm.

3. The method of claim 1, wherein Step S3 comprises: S31. Converting the standard reference person surface element model into a triangular mesh surface element model, separating the main internal organs in the reference person model, and independently adjusting the size and optimizing the spatial position of the separated organs; S32. According to the height adjustment factor and the weight adjustment factor obtained in step S2, preliminarily parametrically adjusting all internal organs; S33. After the preliminary adjustment of the internal organs, according to the organ scaling factor obtained in step S2, performing three-axis equal scaling to make the mass consistent with the target reference person parameters; S34. Position optimization is performed on the adjusted organs to avoid geometric overlap between organs and ensure the rationality and spatial coordination of the anatomical structure.

4. The method of claim 1, wherein In step S4, the whole body tissue comprises lymph nodes, muscles, residual soft tissue, and skin, Step S4 comprises: S41. According to the adjusted organ structure, lymph nodes are generated in the main distribution area of the lymph nodes to avoid overlap with the surrounding organs; S42. Adjust the whole body covering tissues, including muscle, residual soft tissue and skin, to the geometric size of the target reference person according to the height adjustment factor and the weight adjustment factor obtained in step S2. S43. Geometrically process the muscle, residual soft tissue and skin layers in sequence, eliminate the overlapping areas between the tissues, and form a clear and coordinated body structure.

5. The method of claim 4, wherein, In S43, the geometric processing method includes Boolean operation.

6. The method of claim 1, wherein, Step S5 includes: S51. Check whether the weight of the completed model meets the target parameters. If not, adjust the model, and the specific adjustment method is as follows: Fine-tune the thickness of the muscle tissue and residual soft tissue of the standard reference person model modified in the foregoing steps according to the weight of the target reference person, so as to meet the target reference person weight parameter; S52. Output the modified model as a digital reference person model suitable for a specific population, which can be directly used for subsequent dose simulation or radiation protection research.

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