Parameterization reconstruction method of reference person digital model for radiation protection

Abstract

The invention discloses a reference person digital model parameterization reconstruction method for radiation protection, and belongs to the technical field of nuclear radiation protection. The method comprises the following steps: S1, analyzing physiological parameters and anatomical parameters of a target reference person; S2, analyzing the difference between the target reference person and a standard reference person model; S3, carrying out parameterization adjustment on internal organs of the standard reference person model; S4, constructing whole body tissues according to the modification result of the internal organs; generating a target reference person model; according to the method, the applicability and representativeness of the model in diversified crowd dose evaluation are improved, the model construction efficiency is obviously improved, and in addition, the dose evaluation accuracy and the pertinence of protective measures can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear radiation protection, and in particular to a reference person digital model parameterization reconstruction method for radiation protection. BACKGROUND

[0002] Human body models are developed based on the research needs of nuclear radiation protection. The development of human body models has gone through the continuous evolution from simple geometric models, mathematical models, voxel models to surface element models. With the continuous improvement of the fine degree of the model, modern computer human body models not only can accurately describe the overall shape of the human body, but also can reflect the shape, structure and mutual position relationship of each internal main organ in detail, providing a solid theoretical basis for radiation dose assessment, medical imaging and clinical simulation. However, with the improvement of the accuracy and complexity of the model, the difficulty of its construction, correction and maintenance also increases significantly.

[0003] Reference person models are computer human body models constructed based on statistical data, and their anatomical structures are relatively general and can represent the general anatomical structure of a specific population. In radiation protection, reference person models are the core tools for dose calculation and protection standard development. Using Monte Carlo simulation software to calculate the dose of human organs can obtain the radiation absorption and distribution of each part of the human body, providing theoretical basis and data support for radiation protection, risk assessment and standard development.

[0004] However, due to the significant differences in organ mass and body proportions among different populations, such differences refer to the differences between the population data used when a specific reference person is constructed and the target population data. At the same time, the construction of human body models is often limited by the acquisition of whole-body medical images and image segmentation technology, and its construction process is complex and difficult to popularize and apply.

[0005] Traditional dose assessment methods often use a unified standard reference person model for Monte Carlo simulation, which is difficult to reflect the differences among different populations in terms of gender, age, body type, etc., and is difficult to fully reflect the actual situation of the target population. Such differences may cause deviations in dose simulation results, thereby affecting the accuracy and applicability of protection standards.

[0006] In addition, the traditional method often needs to construct digital models for different populations from scratch, which has the problems of complicated process and low efficiency. SUMMARY

[0007] The purpose of the present application is to provide a reference person digital model parameterization reconstruction method for radiation protection to solve the above problems.

[0008] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A reference person digital model parameterization reconstruction method for radiation protection, comprising 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 whole body tissues according to the modification results of the internal organs; S5. Performing model weight adjustment to generate a target reference person model.

[0009] 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. However, the present application introduces key physiological parameters (such as height, weight, organ mass) for parametric adjustment, so that the model can adapt to the statistical characteristics of different populations, thereby improving the applicability and representativeness of the model in dose evaluation of diversified populations.

[0010] In addition, in order to solve the problem that the traditional method often needs to construct digital models of different populations from scratch, which is tedious and inefficient, the present application uses a parametric method to make the adjustment process of the model more automated and systematic, and only a small number of parameters need to be changed to quickly complete the structure adjustment, 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 is 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 protective measures.

[0011] As a preferred technical solution: Step S1 includes: 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; S12. Extract parameters representing the characteristics of this population from the collected data, serving as the physiological and anatomical parameter benchmarks for the target reference person. The parameters representing the characteristics of this population refer to the physiological and anatomical data mentioned in S11, including sex, age, height, weight, organ volume, organ mass, and statistical values ​​of anatomical and physiological parameters of a specific population, scientifically analyzed (e.g., by taking the average or median) to form a dataset describing the physiological and anatomical characteristics of that population. The reference person typicalizes a specific population and is used to represent it, so that different individuals within the population can be treated uniformly on the same biological basis. That is, obtain a dataset that can characterize the physiological and anatomical data of the target population.

[0012] As a preferred technical solution: Step S2 includes: S21. The model to be modified is a structurally complete surface element reference human model; S22. Analyze the differences between the target reference person and the standard reference person model in terms of height, weight, and the mass of internal organs; S23. Based on the height adjustment factor, weight adjustment factor, and organ scaling factor obtained from the difference calculation model in S22, a basis is provided for subsequent parameterization modifications.

[0013] In S21, "model to be modified" refers to the standard reference model, and the model to be constructed, i.e. the target reference model, is modified based on the standard reference model.

[0014] As a further preferred technical solution: In step S23, the height adjustment factor is the height adjustment factor on the z-axis, and its calculation formula is: , in, For height adjustment factor, For the target reference person's height, Standard reference height; The weight adjustment factor is a weight adjustment factor on the x-y plane, and its calculation formula is as follows: , in, For weight adjustment factors, For target reference lean body mass, This is the standard reference lean body mass; After determining the adjustment factors for height and weight, the organs in the model need to be scaled to match the quality of the organs with that of the target reference human model, taking into account the differences in organ quality within the target reference human model. The scaling of internal human organs employs a three-axis proportional scaling method, simultaneously scaling proportionally in the x, y, and z directions. This scaling method ensures that the organ's shape remains unchanged. The formula for calculating the organ scaling factor is as follows: , in, Organ scaling factor The mass of a certain internal organ in a target reference person. The mass of a certain internal organ in a standard reference person.

[0015] As a further preferred technical solution: The calculation formulas for the target reference lean body mass and the standard reference lean body mass both adopt the Boer formula, and gender distinction is made; the calculation formulas for the target reference lean body mass and the standard reference lean body mass for males are as follows: , The formulas for calculating the target reference lean body mass and the standard reference lean body mass for women are as follows: , Where M represents weight in kg and H represents height in cm.

[0016] As a preferred technical solution: Step S3 includes: S31. Convert the standard reference human face model into a triangular mesh face model, separate the main internal organs in the reference human model, and independently adjust the size and optimize the spatial position of the separated organs. S32. Based on the height adjustment factor and weight adjustment factor obtained in step S2, perform preliminary parameterization adjustments on all internal organs; S33. After the initial adjustment, the internal organs are scaled proportionally along three axes according to the organ scaling factor obtained in step S2, so that their quality matches the parameters of the target reference human. S34. Optimize the position of the adjusted organs to avoid geometric overlap between organs and ensure the rationality and spatial coordination of the anatomical structure.

[0017] As a preferred technical solution: In step S4, the systemic tissues include lymph nodes, muscles, remaining soft tissues, and skin. Step S4 includes: S41. Based on the adjusted organ structure, lymph nodes are generated in the main lymph node distribution area to avoid overlapping with surrounding organs; S42. Based on the height adjustment factor and weight adjustment factor obtained in step S2, adjust the full-body covering tissues to conform to the geometric dimensions of the target reference person. The full-body covering tissues include muscles, remaining soft tissues, and skin. S43. Perform geometric processing on the muscles, remaining soft tissues, and skin layer in sequence to eliminate overlapping areas between tissues and form a clear and harmonious body structure.

[0018] As a preferred technical solution In S43, the geometric processing method includes Boolean operations.

[0019] As a preferred technical solution: Step S5 includes: S51. Check if the weight of the completed model meets the target parameters. If not, adjust the model as follows: The thickness of the muscle tissue and remaining soft tissue of the standard reference model modified by the aforementioned steps is fine-tuned according to the weight of the target reference person to make it conform to the weight parameters of the target reference person. It should be noted that what needs to be modified here is the standard reference model; the target reference model is still under construction and is currently just a series of parameters. S52. Output the modified model as a digital reference human model suitable for a specific population, which can be directly used for subsequent dose simulation or radiation protection research.

[0020] This invention introduces key physiological parameters (such as height, weight, and organ mass) for parameterized adjustment, enabling the model to adapt to the statistical characteristics of different populations, thereby improving the applicability and representativeness of the model in dose assessment for diverse populations.

[0021] In particular, steps S2 and S3 are the key inventive points of this application. Existing technologies, such as CN111008461A and CN118553399A, directly construct human models based on the parameters of the target human body without analyzing the differences between the two populations. In contrast, step S2 of this application analyzes the differences between the two models and quantifies these differences to form parameters, namely a series of scaling factors, for use in subsequent model modifications. Step S2 is the preparatory work for model reconstruction, providing modification parameters for subsequent model modifications. The quantitative differences in step S2 can intuitively demonstrate the physiological differences between the two populations, highlighting the key areas for model modification. Simultaneously, the scaling factor can guide researchers in analyzing the accuracy of radiation dose simulations. For example, significant differences in height / weight can lead to differences in whole-body dose, while large differences in the mass of a particular organ can result in dose differences for that organ, surrounding organs, and even the entire body. Step S3 involves parametric modification of internal organs, with the main parameter source being the organ scaling factor in step S2. Existing technologies such as CN115797313A and CN118553399A modify the model for posture adjustment, without modifying the internal organs of the overall model to transform it into a reference human model that conforms to the parameters of other populations. Through step S3 of this application, a general adjustment strategy and scaling logic are constructed based on the parametric design concept, which does not depend on a specific model structure or specific population data. If it is necessary to adapt to new statistical populations in the future, only the model scaling factor needs to be recalculated, without redesigning the entire methodological framework. This method has good adaptability and scalability.

[0022] Compared with the prior art, the advantages of the present invention are: the present invention improves the applicability and representativeness of the model in dose assessment of diverse populations, significantly improves the model construction efficiency, and the method of the present invention can improve the accuracy of dose assessment and the pertinence of protective measures. Attached Figure Description

[0023] Figure 1 This is a flowchart of the construction method of the present invention; Figure 2 This is a revised diagram of the internal organs and tissues of a human reference. Figure 3 A half-section view of the whole body tissues of the target reference human model. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments.

[0025] Example 1: See Figure 1 A method for parametric reconstruction of a reference human digital model for radiation protection includes the following steps: S1. Analyze the physiological and anatomical parameters of the target human: S11. Collect physiological and anatomical data of the target population, including but not limited to gender, age, height, weight, organ volume, organ mass, etc.; the data sources may be population physical databases, CT or MRI anatomical image analysis results, and phantom databases, etc. S12. Extract parameters representing the characteristics of this population from the collected data, and use them as a benchmark for the physiological and anatomical parameters of the target reference person; Specifically, in this embodiment, the data in the GBZ / T200 standard "Reference Man for Radiation Protection" are used as the physiological and anatomical parameters of the target reference man.

[0026] S2. Analyze the differences between the target reference person and the standard reference person model: In this embodiment, the standard reference human model used is the Adult Grid Reference Computational Phantom (MRCP) published by the International Commission on Radiological Protection (ICRP).

[0027] Furthermore, in this embodiment, the standard reference model used is a male MRCP reference model; The differences between the parameters of the target reference person and the parameters of the standard reference person model are compared, mainly analyzing the differences in height, weight, and the mass of internal organs. Based on these differences, scaling factors for the model are calculated, including height adjustment factors, weight adjustment factors, and organ scaling factors, providing a basis for subsequent parameterization modifications. Height difference is determined by calculating the ratio of the target reference height to the standard reference height. The formula for calculating the height adjustment factor on the z-axis is: , in, For height adjustment factor, For the target reference person's height, This is for reference only.

[0028] Weight difference is determined by calculating the ratio of the target reference model's weight to the standard reference model's weight, resulting in a weight adjustment factor on the x and y planes. , in, For weight adjustment factors, For target reference lean body mass, This is the standard reference lean body mass.

[0029] The calculation formulas for both the target reference lean body mass and the standard reference lean body mass adopt the Boer formula, and gender distinction is made: For target reference lean body mass and standard reference lean body mass in men: , The formulas for calculating the target reference lean body mass and the standard reference lean body mass for women are as follows: , Where M represents weight (kg) and H represents height (cm).

[0030] After initial adjustments to height and weight, the difference analysis module further adjusts the internal organs. Addressing the differences in organ mass within the target reference model, each organ in the model undergoes three-axis scaling to match its mass to the target reference model. The scaling of the internal organs employs a three-axis proportional scaling method, meaning simultaneous proportional scaling in the x, y, and z directions. This scaling method ensures that the organ's shape remains unchanged. ,

[0031] in, Organ scaling factor The mass of a certain internal organ in a target reference person. The mass of a certain internal organ in a standard reference person; Specifically, in the embodiments, the weight and height of the target reference person, constructed from the data in the GBZ / T200 "Reference Person for Radiation Protection" standard, and the standard reference person, based on the MRCP model published by ICRP, are shown in Table 1: Table 1 Height and weight of target and standard reference persons , Based on the data in Table 1, the height adjustment factor is calculated to be 0.965, and the weight adjustment factor is calculated to be 0.966. The calculation results of organ scaling factors for some tissues and organs are shown in Table 2: Table 2 shows the calculation results of organ scaling factors for some tissues and organs. , S3. Parametrically modify the internal organs of the standard reference human model: First, import the MRCP model into Rhino8, and then use the mesh processing module in Rhino8 to convert the model into a triangular mesh element model.

[0032] The internal organs in the reference human model were separated using the Grasshopper plugin of Rhion8. The separated organs can be independently adjusted in size and optimized in spatial position.

[0033] Furthermore, the height adjustment factor and weight adjustment factor obtained in step S2 are imported into Grasshopper, and the scaling module in Grasshopper is used to perform preliminary parametric adjustments on all internal organs. The height adjustment factor is applied to the z-axis scaling of the model, while the weight adjustment factor is applied to the x-axis and y-axis scaling of the model.

[0034] Import the organ scaling factor obtained in step S2 into Grasshopper, and then use the scaling module in Grasshopper to scale the separated internal organs in three axes proportionally so that their quality matches the parameters of the target reference human. Using the mesh collision detection module in Grasshopper, the positions of the adjusted organs were optimized to avoid geometric overlap between organs, ensuring the rationality of the anatomical structure and spatial harmony. The modified reference human internal tissue and organ structure is shown below. Figure 2 As shown.

[0035] S4. Reconstruct the entire body's tissues based on the modifications made to internal organs: In this embodiment, the whole body tissues include lymph nodes, muscles, remaining soft tissues, and skin; wherein the remaining soft tissues are a fictional human tissue used to uniformly represent non-main organ soft tissues such as fat, blood vessels, and nerves that are difficult to describe separately in modeling. These tissues play a small role in radiation dose assessment but cannot be ignored in the overall mass composition.

[0036] Specifically, the whole-body tissues are constructed in the following manner: In Grasshopper, lymph nodes are generated in the main distribution areas of lymph nodes based on the parameterized internal organ structure. The geometric algorithm in Grasshopper ensures that the generated lymph nodes do not spatially overlap with adjacent organs. The main distribution areas of lymph nodes include: the neck, armpits, chest, groin, and limbs; Import the height and weight adjustment factors obtained in step S2 into Grasshopper and adjust the full-body covering tissues (muscles, remaining soft tissues, and skin) to conform to the geometric dimensions of the target reference person. The height adjustment factor is applied to the z-axis scaling of the model, while the weight adjustment factor is applied to the x-axis and y-axis scaling of the model.

[0037] Geometric processing methods, such as Boolean operations, are applied sequentially to the muscles, remaining soft tissues, and skin layers to eliminate overlapping areas between tissues, resulting in a clear and harmonious body structure.

[0038] S5. Adjust the model's weight and generate a target reference model: After the construction of internal organs and whole body tissues is completed, in order to ensure that the weight of the final model matches the target reference, the whole body covering tissues of the model need to be fine-tuned. Specifically, in the Grasshopper modeling environment, the thickness of muscle tissue and remaining soft tissue is adjusted to increase or decrease the weight of the reference person. After the overall model adjustment is completed, the parametrically modified internal organs and reconstructed lymph nodes, muscles, remaining soft tissues, and skin will form a well-structured mesh model, with a half-section view of the whole body tissues as shown below. Figure 3 As shown; Establish identifiable numerical indexes and names for each organ / tissue grid in the model to facilitate subsequent dose simulations or model modification needs.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for parametric reconstruction of a reference human digital model for radiation protection, characterized in that, Includes the following steps: S1. The analysis targets refer to human physiological and anatomical parameters; S2. Analyze the differences between the target reference person and the standard reference person model; S3. Parametrically adjust the internal organs of the standard reference human model; S4. Construct the whole body tissues based on the modification results of internal organs; S5. Adjust the model weight to generate a target reference model.

2. The method according to claim 1, characterized in that, Step S1 includes: S11. Collect physiological and anatomical data of the target population, including gender, age, height, weight, organ volume, and organ mass; S12. Extract parameters representing the characteristics of the population from the collected data, and use them as a benchmark for the physiological and anatomical parameters of the target reference person.

3. The method according to claim 1, characterized in that, Step S2 includes: S21. The model to be modified is a structurally complete surface element reference human model; S22. Analyze the differences between the target reference person and the standard reference person model in terms of height, weight, and the mass of internal organs; S23. Based on the height adjustment factor, weight adjustment factor, and organ scaling factor obtained from the difference calculation model in S22, a basis is provided for subsequent parameterization modifications.

4. The method according to claim 3, characterized in that, In step S23, the height adjustment factor is the height adjustment factor on the z-axis, and its calculation formula is: ， in, For height adjustment factor, For the target reference person's height, Standard reference height; The weight adjustment factor is a weight adjustment factor on the x-y plane, and its calculation formula is as follows: ， in, For weight adjustment factors, For target reference lean body mass, This is the standard reference lean body mass; The scaling of internal human organs employs a three-axis proportional scaling method, simultaneously scaling proportionally in the x, y, and z directions. This scaling method ensures that the organ's shape remains unchanged. The formula for calculating the organ scaling factor is as follows: ， in, Organ scaling factor The mass of a certain internal organ in a target reference person. The mass of a certain internal organ in a standard reference person.

5. The method according to claim 4, characterized in that, The calculation formulas for the target reference lean body mass and the standard reference lean body mass both adopt the Boer formula, and gender distinction is made; the calculation formulas for the target reference lean body mass and the standard reference lean body mass for males are as follows: ， The formulas for calculating the target reference lean body mass and the standard reference lean body mass for women are as follows: ， Where M represents weight in kg and H represents height in cm.

6. The method according to claim 1, characterized in that, Step S3 includes: S31. Convert the standard reference human face model into a triangular mesh face model, separate the main internal organs in the reference human model, and independently adjust the size and optimize the spatial position of the separated organs. S32. Based on the height adjustment factor and weight adjustment factor obtained in step S2, perform preliminary parameterization adjustments on all internal organs; S33. After the initial adjustment, the internal organs are scaled proportionally along three axes according to the organ scaling factor obtained in step S2, so that their quality matches the parameters of the target reference human. S34. Optimize the position of the adjusted organs to avoid geometric overlap between organs and ensure the rationality and spatial coordination of the anatomical structure.

7. The method according to claim 1, characterized in that, In step S4, the systemic tissues include lymph nodes, muscles, remaining soft tissues, and skin. Step S4 includes: S41. Based on the adjusted organ structure, lymph nodes are generated in the main lymph node distribution area to avoid overlapping with surrounding organs; S42. Based on the height adjustment factor and weight adjustment factor obtained in step S2, adjust the full-body covering tissues to conform to the geometric dimensions of the target reference person. The full-body covering tissues include muscles, remaining soft tissues, and skin. S43. Perform geometric processing on the muscles, remaining soft tissues, and skin layer in sequence to eliminate overlapping areas between tissues and form a clear and harmonious body structure.

8. The method according to claim 7, characterized in that, In S43, the geometric processing method includes Boolean operations.

9. The method according to claim 1, characterized in that, Step S5 includes: S51. Check if the weight of the completed model meets the target parameters. If not, adjust the model as follows: The thickness of the muscle tissue and remaining soft tissue of the standard reference model modified by the aforementioned steps is fine-tuned according to the weight of the target reference person to make it conform to the weight parameters of the target reference person. S52. Output the modified model as a digital reference human model suitable for a specific population, which can be directly used for subsequent dose simulation or radiation protection research.

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