Methods, apparatus, equipment, media and products for passive efficiency calibration of internal human irradiation

Abstract

The present application discloses a method, device, equipment, medium and product for calibrating passive efficiency of human body irradiation, and relates to the technical field of human body irradiation detection. The method is to first reconstruct a three-dimensional respiratory model of a target human body, and then use finite element analysis software to calculate the flow field distribution of the fluid inside the three-dimensional respiratory model under the target environment and when the human body breathes according to the physical properties of the fluid in the respiratory tract, and calculate the movement of the simulated particles under the flow field distribution, and obtain the deposition information of the simulated particles on the inner wall of the respiratory tract, and then import the deposition information into the Monte Carlo simulation software to simulate the ray emission, and obtain the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector, and finally complete the passive efficiency calibration task of the detector according to the measurement data, so that not only the accuracy of the simulation experiment can be effectively improved, but also comprehensive experiments can be carried out for different populations and detectors, effectively improving practicality.

Description

Technical Field

[0001] The present invention belongs to the technical field of human body internal irradiation detection, and specifically relates to a method, device, equipment, medium and product for calibrating passive efficiency of human body internal irradiation. Background Art

[0002] Air pollution in radioactive workplaces refers to tiny radioactive colloidal particles or gases suspended in the air, which may be released into the surrounding environment on a large scale, and eventually have adverse effects on the human body. After the radioactive nuclides are ingested into the body, they will be deposited and retained in the tissues or organs they are attached to, causing radiation doses and causing harm. Among them, radioactive aerosols are crucial for assessing the respiratory exposure dose of occupational personnel. The traditional calculation method assumes that the radioactive nuclides in the aerosols enter the respiratory tract of the workers completely through breathing, and uses the default value of the International Commission on Radiological Protection (ICRP) as the conversion factor for internal exposure of nuclides. However, in actual situations, the deposition position and amount of aerosols in the respiratory tract depend on their diameter and the human breathing rate. Therefore, simply assuming that aerosols are completely deposited in the respiratory tract or a specific area will be quite different from the actual situation.

[0003] The radioactive aerosols emitted into the atmosphere by global atmospheric nuclear tests, nuclear facility accidents, and nuclear technology applications mainly include argon (Ar-41), cobalt (Co-60), strontium (Sr-90), iodine (I-131), xenon (Xe-133), cesium (Cs-137), radon (Rn-222), radium (Ra-226), and / or uranium (U-235). When aerosols containing these radioactive substances are inhaled by the human body, they will continue to irradiate the corresponding deposition sites of the human body for a period of time. Some radionuclides may even exist in the human body for life due to factors such as long decay periods. For internal radiation dose evaluation, the commonly used detection methods are selected in the following order: in vitro direct measurement, biological sample analysis, and air sampling analysis. In actual situations, one or more of these measurement methods should be selected for measurement according to the specific situation.

[0004] Usually, direct in vitro measurement is the most effective method for estimating internal radiation dose. It is to bring the radiation detector close to the human body to detect the rays emitted from the human body and that can pass through human tissue. It can be used to detect radionuclides that can release characteristic X-rays, gamma rays, positrons and high-energy beta particles. The equipment used for direct measurement consists of one or more high-efficiency detectors installed in a low-background environment.

[0005] Before using a measuring device to measure the human body, the detection efficiency of the relevant measuring equipment must be calibrated. The conventional efficiency calibration methods currently include: active efficiency curve method and passive efficiency calibration method. Due to the problems of complex operation, time-consuming and difficulty in evaluating errors in the active efficiency curve method, it is gradually being replaced by the passive efficiency calibration technology.

[0006] In the existing passive efficiency calibration technology, the efficiency calibration of the human body radiation dose is mainly based on the human body model recommended by ICRP. However, in reality, there are obvious individual differences in the human body, and under the same environment, the radiation contamination conditions in different people are also different. The method of simply using the human body model to calibrate the efficiency of the detection instrument is relatively rough. Summary of the invention

[0007] The purpose of the present invention is to provide a method, device, computer equipment, computer-readable storage medium and computer program product for calibrating the passive efficiency of human body irradiation, so as to solve the problem that the accuracy of the efficiency calibration cannot be improved due to the individual differences of the human body and the lack of reference to more physical factors in the existing technology of calibrating the passive efficiency of human body irradiation.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, a method for calibrating passive efficiency of human body irradiation is provided, comprising:

[0010] Reconstructing a three-dimensional respiratory tract model of the target human body, wherein the three-dimensional respiratory tract model includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model, and a main bronchial bifurcation structure sub-model;

[0011] According to the physical properties of the fluid in the respiratory tract, the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body breathes is calculated using finite element analysis software, wherein the fluid in the respiratory tract is a turbulent, constant-temperature and incompressible Newtonian fluid, and the environmental parameters of the target environment include gravity field parameters and temperature field parameters;

[0012] Adding simulated particles with the physical properties of aerosols into the three-dimensional respiratory model, and using the finite element analysis software to calculate the movement of the simulated particles under the flow field distribution, to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes the deposition position or the deposition position and the deposition amount;

[0013] Importing the respiratory tract three-dimensional model into Monte Carlo simulation software, and adding a human tissue three-dimensional model for simulating the scattering and energy attenuation of rays in soft tissue structures around the respiratory tract three-dimensional model, and also placing a Monte Carlo model of a target detector around the human tissue three-dimensional model;

[0014] Importing the deposition information into the Monte Carlo simulation software to perform ray emission simulation to obtain measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector;

[0015] According to the measurement data, the passive efficiency calibration task of the target detector is completed.

[0016] Based on the above invention content, a new scheme is provided for improving the passive efficiency calibration of human body irradiation by coupling finite element analysis of multiple physical fields on the basis of traditional Monte Carlo simulation, that is, firstly reconstructing a three-dimensional respiratory model of a target human body, and then using finite element analysis software to calculate the flow field distribution of the fluid inside the three-dimensional respiratory model under the target environment and when the human body is breathing, according to the physical properties of the fluid in the respiratory tract, and calculating the movement of the simulated particles under the flow field distribution, to obtain the deposition information of the simulated particles on the inner wall of the respiratory tract, and then importing the deposition information into the Monte Carlo simulation software to perform ray emission simulation, to obtain the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector, and finally completing the passive efficiency calibration task of the detector according to the measurement data. Compared with the traditional scheme, the accuracy of the simulation experiment can be effectively improved by comprehensively calculating the specific model structure, gravity field, temperature field and fluid flow field, and comprehensive experiments can also be carried out for different populations and different detectors, which effectively improves the practicality and facilitates practical application and promotion.

[0017] In a possible design, a three-dimensional respiratory model of the target human body is reconstructed, including:

[0018] Acquire respiratory tract CT data of the target human body;

[0019] According to the respiratory tract CT data, a three-dimensional model of the upper respiratory tract of the target human body is established, wherein the three-dimensional model of the upper respiratory tract includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main trachea sub-model;

[0020] Based on the main trachea sub-model, a multi-level bronchial sub-model connected to the main trachea sub-model and having a bilaterally symmetrical structure is established, and a main bronchial bifurcation structural sub-model including the main trachea sub-model and the multi-level bronchial sub-model is obtained, and a respiratory tract three-dimensional model of the target human body including the anterior nasal passage sub-model, the posterior nasal passage sub-model, the nose and mouth sub-model, the laryngeal sub-model and the main bronchial bifurcation structural sub-model is obtained, wherein the angle of each bronchial bifurcation of the multi-level bronchial sub-model is rounded by a length of Smooth rounded corners, Indicates the cross-sectional diameter of the bronchus at the bronchial bifurcation.

[0021] In a possible design, adding simulated particles having the physical properties of aerosols to the inside of the three-dimensional respiratory model, and using the finite element analysis software to calculate the movement of the simulated particles under the flow field distribution, to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, includes:

[0022] Acquire initial configuration information of simulated particles, wherein the simulated particles have physical properties of aerosols, and the initial configuration information includes initial coordinates, initial velocity, particle density, particle diameter, and particle mass flow rate, wherein the initial coordinates are at the respiratory inlet cross section of the respiratory tract three-dimensional model, the initial velocity is consistent with the initial velocity of the fluid in the respiratory tract, and the particle mass flow rate refers to the total mass of particles passing through the respiratory inlet cross section of the respiratory tract three-dimensional model within one second;

[0023] According to the initial configuration information of the simulated particles, the simulated particles are added to the three-dimensional respiratory model, and the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes the deposition position or the deposition position and the deposition amount.

[0024] In a possible design, using the finite element analysis software to calculate the motion of the simulated particles under the flow field distribution condition includes:

[0025] Using a random walk model to simulate the random movement of the simulated particles in the internal space of the three-dimensional respiratory tract model;

[0026] Alternatively, for simulated particles whose size dimension is larger than the molecules of the fluid in the respiratory tract, a random walk model and a Stokes-Cunningham drag model are used to simulate the random motion of the corresponding particles in the internal space of the three-dimensional respiratory tract model.

[0027] In one possible design, the deposition information is imported into the Monte Carlo simulation software to perform ray emission simulation, including:

[0028] Importing the deposition position in the deposition information into the Monte Carlo simulation software as the position where the radioactive aerosol becomes a radiation source and generates radioactive rays after being deposited on the inner wall of the three-dimensional respiratory tract model;

[0029] Random trigonometric equations are used to simulate and calculate the emission direction of radioactive rays generated by a radiation source.

[0030] In a possible design, the physical properties of the fluid in the respiratory tract include fluid density, fluid viscosity, fluid initial velocity, fluid turbulent kinetic energy, and fluid turbulent dissipation rate;

[0031] And / or, the flow field distribution includes fluid velocity distribution and fluid pressure distribution.

[0032] In a second aspect, a device for calibrating passive efficiency of irradiation in human body is provided, including a three-dimensional model reconstruction unit, a flow field distribution calculation unit, a particle motion calculation unit, a simulation model arrangement unit, a ray emission simulation unit and a calibration task completion unit;

[0033] The three-dimensional model reconstruction unit is used to reconstruct a three-dimensional respiratory tract model of the target human body, wherein the three-dimensional respiratory tract model includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main bronchial bifurcation structure sub-model;

[0034] The flow field distribution calculation unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to calculate the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body breathes, using finite element analysis software according to the physical properties of the fluid in the respiratory tract, wherein the fluid in the respiratory tract is a turbulent, constant-temperature and incompressible Newtonian fluid, and the environmental parameters of the target environment include gravity field parameters and temperature field parameters;

[0035] The particle motion calculation unit is communicatively connected to the flow field distribution calculation unit, and is used to add simulated particles having the physical properties of aerosols into the three-dimensional respiratory model, and use the finite element analysis software to calculate the motion of the simulated particles under the flow field distribution condition, and obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes a deposition position or a deposition position and a deposition amount;

[0036] The simulation model arrangement unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to import the three-dimensional respiratory tract model into the Monte Carlo simulation software, and to add a three-dimensional human tissue model for simulating the scattering and energy attenuation of rays in the soft tissue structure around the three-dimensional respiratory tract model, and to place a Monte Carlo model of a target detector around the three-dimensional human tissue model;

[0037] The ray emission simulation unit is respectively connected to the particle motion calculation unit and the simulation model arrangement unit for communication, and is used to import the deposition information into the Monte Carlo simulation software to perform ray emission simulation, and obtain measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector;

[0038] The calibration task completion unit is communicatively connected to the ray emission simulation unit, and is used to complete the passive efficiency calibration task of the target detector according to the measurement data.

[0039] In a third aspect, the present invention provides a computer device comprising a memory, a processor and a transceiver which are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the method for passive efficiency calibration of in vivo irradiation as described in the first aspect or any possible design of the first aspect.

[0040] In a fourth aspect, the present invention provides a computer-readable storage medium having instructions stored thereon, which, when executed on a computer, executes the method for calibrating the passive efficiency of in vivo irradiation as described in the first aspect or any possible design of the first aspect.

[0041] In a fifth aspect, the present invention provides a computer program product, comprising a computer program or instructions, which, when executed by a computer, implement the method for calibrating passive efficiency of in vivo irradiation as described in the first aspect or any possible design of the first aspect.

[0042] Beneficial effects of the above scheme:

[0043] (1) The present invention creatively provides a new scheme for improving the calibration of passive efficiency of human body irradiation by coupling finite element analysis of multiple physical fields based on traditional Monte Carlo simulation, that is, firstly reconstructing a three-dimensional respiratory model of the target human body, and then using finite element analysis software to calculate the flow field distribution of the fluid in the three-dimensional respiratory model under the target environment and when the human body is breathing, and calculating the movement of simulated particles under the flow field distribution, to obtain the deposition information of simulated particles on the inner wall of the respiratory tract, and then importing the deposition information into Monte Carlo simulation software to simulate the ray emission, to obtain the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector, and finally completing the passive efficiency calibration task of the detector based on the measurement data. Compared with the traditional scheme, the accuracy of the simulation experiment can be effectively improved by comprehensively calculating the specific model structure, gravity field, temperature field and fluid flow field, etc., and comprehensive experiments can also be carried out for different populations and different detectors, which effectively improves the practicality and facilitates practical application and promotion;

[0044] (2) It can more efficiently and accurately calibrate the efficiency of internal radiation detectors when detecting human breathing. At the same time, this method theory can also be used in other fields, such as controlling the drug flow rate and atomized particle size during atomized drug inhalation therapy;

[0045] (3) Since the finite element analysis of multi-physics fields is coupled on the basis of traditional Monte Carlo simulation to improve the accuracy of the overall experiment, the optimal efficiency scale can be achieved;

[0046] (4) According to the actual situation of the patient, it can simulate the situation that when the patient has chronic obstructive pulmonary disease, some bronchial segments of the respiratory tract cannot effectively circulate oxygen or carbon dioxide smoothly;

[0047] (5) It can also accurately simulate the main deposition location distribution of aerosol particles and other substances in the respiratory tract under human respiration, which will help provide a reference for the treatment of related radiation occupational diseases in the later stage;

[0048] (6) Compared with the traditional internal irradiation passive efficiency calibration, the passive efficiency calibration of the internal irradiation detector can be more accurate. That is, the traditional passive efficiency calibration assumes that the radiation source is evenly distributed in the respiratory tract or is set individually according to empirical formulas. This will cause the Monte Carlo analysis to be inconsistent with the actual situation, resulting in certain errors in the results, which is not conducive to the future development of the passive efficiency calibration of internal irradiation detectors under nanodose. This scheme does not have this concern. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0050] Figure 1 A schematic flow chart of a method for calibrating passive efficiency of in vivo irradiation provided in an embodiment of the present application.

[0051] Figure 2 This is an example diagram of the three-dimensional respiratory model provided in an embodiment of the present application.

[0052] Figure 3 This is an example diagram of a combination of a three-dimensional respiratory tract model and a three-dimensional human tissue model for calibrating passive efficiency of irradiation in the human body provided in an embodiment of the present application.

[0053] Figure 4 This is an example diagram of a Monte Carlo model of a target detector for calibrating passive efficiency of in vivo illumination provided in an embodiment of the present application.

[0054] Figure 5 This is an example diagram of the positional relationship between the respiratory tract three-dimensional model and the human tissue three-dimensional model provided in the embodiment of the present application and the Monte Carlo model of the target detector.

[0055] Figure 6 The schematic diagram of the flow velocity distribution of the flow field in the respiratory tract after finite element analysis provided in the embodiment of the present application, wherein: Figure 6 (a) shows a front view, Figure 6 (b) shows a side view.

[0056] Figure 7 A schematic diagram of the distribution of particles deposited on the inner wall of the respiratory tract after finite element analysis provided in an embodiment of the present application.

[0057] Figure 8 This is a graph showing the changing trend of the deposition distribution of particles of different particle sizes in the respiratory tract provided in the embodiments of the present application.

[0058] Fig. 9 This is an example diagram of the radiation energy of different aerosol particles with different diameters detected by the detector provided in the embodiment of the present application, wherein: Fig. 9 (a) shows an example of the energy of the radiation of Co-60 aerosol particles with different diameters detected by the detector. Fig. 9 (b) shows an example diagram of the radiation energy of Cs-137-based aerosol particles with different diameters detected by the detector.

[0059] Fig.10 A schematic diagram of the structure of a passive efficiency calibration device for in vivo irradiation provided in an embodiment of the present application.

[0060] Fig.11 A schematic diagram of the structure of a computer device provided in an embodiment of the present application.

[0061] In the above figures: 11 - nasal cavity; 12 - oral cavity; 13 - main trachea; 14 - bronchus; 20 - lung tissue; 30 - soft tissue; 101 - beryllium window; 102 - aluminum shell; 103 - germanium crystal; 104 - vacuum environment chamber. DETAILED DESCRIPTION

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the present invention will be briefly introduced below in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structures of the drawings is only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these embodiments without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0063] It should be understood that although the terms first and second, etc. may be used herein to describe various objects, these objects should not be limited by these terms. These terms are only used to distinguish one object from another object. For example, a first object can be referred to as a second object, and similarly, a second object can be referred to as a first object without departing from the scope of the exemplary embodiments of the present invention.

[0064] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that there may be three relationships. For example, A and / or B can indicate three situations: A exists alone, B exists alone, or A and B exist at the same time. For another example, A, B and / or C can indicate the existence of any one of A, B and C or any combination of them. The term " / and" that may appear in this document describes another type of association object relationship, indicating that there may be two relationships. For example, A / and B can indicate two situations: A exists alone or A and B exist at the same time. In addition, the character " / " that may appear in this document generally indicates that the previous and next associated objects are in an "or" relationship.

[0065] Example

[0066] like Figure 1 As shown, the method for calibrating the passive efficiency of human body irradiation provided in the first aspect of this embodiment can be, but is not limited to, executed by a computer device with certain computing resources, such as a cloud server or other computer device. Figure 1As shown, the method for calibrating the passive efficiency of in vivo irradiation may include, but is not limited to, the following steps S1 to S6.

[0067] S1. Reconstruct a three-dimensional respiratory tract model of the target human body, wherein the three-dimensional respiratory tract model includes but is not limited to an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model, and a main bronchial bifurcation structure sub-model.

[0068] In step S1, the target human body can be a standard human body of a certain group of people, or a personalized human body of a certain person. Specifically, reconstructing the respiratory tract three-dimensional model of the target human body includes but is not limited to the following steps S11 to S13.

[0069] S11. Obtain respiratory tract CT (Computed Tomography) data of the target human body.

[0070] S12. Based on the respiratory tract CT data, a three-dimensional model of the upper respiratory tract of the target human body is established, wherein the three-dimensional model of the upper respiratory tract includes but is not limited to an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main trachea sub-model.

[0071] In step S12, the reconstruction of the upper respiratory tract three-dimensional model can be completed specifically through relevant medical software (such as Mimics Medical). In the process of constructing the upper respiratory tract three-dimensional model, the front end of the nasal cavity can be cross-sectioned according to the dosimetry and morphological characteristics of the human respiratory tract to ensure that the end surface is in a geometric coordinate plane, which can be used for the kinematic finite element simulation of nasal breathing in the later stage; at the same time, the mouth is constructed into a lip closed state and a mouth slightly open state according to the normal breathing state of the human body; and the lips are segmented into upper lips and lower lips, and in the later simulation, the opening angle of the lips can also be controlled to simulate the kinematic finite element simulation of mouth breathing of the human body in different states.

[0072] S13. Based on the main trachea sub-model, a multi-level bronchial sub-model connected to the main trachea sub-model and having a bilaterally symmetrical structure is established to obtain a main bronchial bifurcation structural sub-model including the main trachea sub-model and the multi-level bronchial sub-model, and a respiratory tract three-dimensional model of the target human body including the anterior nasal passage sub-model, the posterior nasal passage sub-model, the nose and mouth sub-model, the laryngeal sub-model and the main bronchial bifurcation structural sub-model is obtained, wherein the angle of each bronchial bifurcation of the multi-level bronchial sub-model is rounded by a length of Smooth rounded corners, Indicates the cross-sectional diameter of the bronchus at the bronchial bifurcation.

[0073] In the step S13, considering that the ICRP report mentioned that lung cancer caused by radiation, such as small cell lung cancer or squamous cell carcinoma, is mainly concentrated in the main bronchus area (that is, from the main bronchus to the bronchioles, it can be divided into 16 levels of structure, and the main bronchus area is a level 0 to 8 structure, where level 0 is the main bronchus. Since the airway is long and curved in reality, it is established using CT scan data), the multi-level bronchial sub-model can be specifically a level 1 to 8 structure: a total of 316 entity models can be established to simulate the respiratory model of patients with certain respiratory diseases in a specific environment. For example, the three-dimensional respiratory model can be exemplified as follows: Figure 2 In addition, it is also considered that aerosols are prone to accumulation at the airway bifurcation with breathing, and in the real human trachea model, each bronchial bifurcation needs to present a certain curvature. Due to the lack of relevant data in ICRP, the angle of the tracheal bifurcation needs to be rounded and smoothed in length in the actual three-dimensional model. The data of the relevant structure are shown in Table 1 below.

[0074] Table 1. Parameters of the multi-level bronchial sub-model

[0075]

[0076] S2. According to the physical properties of the fluid in the respiratory tract, finite element analysis software is used to calculate the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body is breathing, wherein the fluid in the respiratory tract is a turbulent, constant temperature and incompressible Newtonian fluid, and the environmental parameters of the target environment include gravity field parameters and temperature field parameters.

[0077] In step S2, the fluid in the respiratory tract is air fluid. Considering that when simulating human breathing, the airflow inside the respiratory tract will be affected by multiple factors such as the geometric shape of the respiratory tract, the viscosity and inertia of the airflow, the speed, direction and turbulence of the airflow entering the respiratory tract, etc., the final simulation result will directly affect the deposition of aerosols in the respiratory tract. Therefore, the physical properties of the fluid in the respiratory tract include but are not limited to fluid density, fluid viscosity, fluid initial velocity, fluid turbulent kinetic energy and fluid turbulent dissipation rate, etc., wherein the fluid density and the fluid viscosity are specifically set separately according to the simulation environment, for example, the fluid density is set to 1.225kg / m 3 and the fluid viscosity is 0.000017894kg / (m﹒s), and the initial velocity of the fluid is set at the entrance of the nasal cavity or oral cavity. (in, represents the tidal volume of the breath, Indicates the duration of inhalation during breathing. represents the cross-sectional area at the nasal opening), the turbulent kinetic energy of the fluid The calculation formula is (in, represents the density of the fluid; Indicates time; represents the fluid velocity component; Represents spatial coordinates; represents the jth component in the spatial coordinates; It represents the dynamic viscosity of the fluid; represents the turbulent viscosity, which can be corrected with The relevant model parameters are calculated; Usually the value is 1.0 or 1.3; represents the generation term of turbulent energy, usually calculated through the model), fluid turbulence dissipation rate The calculation formula is (in, It indicates the proportional relationship between the generation of turbulent dissipation rate and the consumption of turbulent energy, which is generally It is set to 0.9 in the model; It indicates the proportional relationship between the degree of dissipation and the magnitude of turbulent energy, which determines the turbulent dissipation rate. It is also considered that when performing aerosol deposition simulation, simulating the airflow and pressure inside the respiratory tract during human breathing can provide basic information, provide accurate boundary conditions and input parameters for subsequent aerosol deposition simulation, and thus obtain more reliable simulation results. Therefore, this step needs to be performed before the subsequent step S3. In addition, the environmental parameters of the target environment specifically include but are not limited to gravity field parameters (for example, setting the gravity acceleration to 9.81 m / s 2 , direction is parallel to the 0-level main air pipe and vertically downward) and temperature field parameters (for example, setting the ambient temperature to 298.15K); the flow field distribution includes but is not limited to the fluid velocity distribution and the fluid pressure distribution, such as Figure 6 shown.

[0078] S3. Add simulated particles with the physical properties of aerosols to the interior of the three-dimensional respiratory model, and use the finite element analysis software to calculate the movement of the simulated particles under the flow field distribution, to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes the deposition position or the deposition position and the deposition amount.

[0079] In step S3, after the finite element analysis software is used to calculate the flow of the continuous phase (i.e., air) until the flow field converges, particles need to be added for coupling solution. In particular, after particles such as aerosols enter the respiratory tract, they will change their direction of movement as the airflow passes through complex mechanisms such as the mouth, pharynx, larynx, trachea, and bronchi, and deposit or adhere to the inner wall of the respiratory tract. Some particles will also be directly captured by the inner wall of the respiratory tract due to factors such as gravity, air resistance, and eddy currents. In view of the influence of the above key factors, different physical parameters need to be set, and corresponding modifications need to be made to particles of different particle sizes in order to achieve the optimal simulation results. Specifically, a calculation mode can be used to simulate and calculate the deposition position and proportion of particles in the respiratory tract at different particle sizes, so as to obtain more accurate simulation results and provide guarantee for the subsequent passive efficiency calibration. That is, preferably, simulated particles with the physical properties of aerosols are added to the inside of the three-dimensional respiratory model, and the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution, and the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model is obtained, including but not limited to the following steps S31 to S32.

[0080] S31. Obtaining initial configuration information of the simulated particles, wherein the simulated particles have physical properties of aerosols, and the initial configuration information includes but is not limited to initial coordinates, initial velocity, particle density, particle diameter, and particle mass flow rate, etc. The initial coordinates are at the respiratory inlet cross section of the three-dimensional respiratory model, the initial velocity is consistent with the initial velocity of the fluid in the respiratory tract, and the particle mass flow rate refers to the total mass of particles passing through the respiratory inlet cross section of the three-dimensional respiratory model within one second.

[0081] In step S31, the simulated particles of 1um, 3um, 5um, 7um and 10um can be created respectively according to the design requirements to simulate aerosol deposition, wherein the particle density is 3000kg / m 3 According to the human body's 3-second breathing cycle, 15,000 particles are injected within 0 to 1.5 seconds to simulate the aerosol inhaled by the human body.

[0082] S32. According to the initial configuration information of the simulated particles, the simulated particles are added to the three-dimensional respiratory model, and the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes but is not limited to the deposition position or the deposition position and the deposition amount.

[0083] In step S32, since the influence of fluid turbulence on particle motion trajectory needs to be considered when calculating the coupling between particles and fluid, preferably, the finite element analysis software is used to calculate the motion of the simulated particles under the flow field distribution, including: using a random walk model to simulate the random motion of the simulated particles in the internal space of the three-dimensional respiratory model. The random walk model can be expressed in three dimensions as ,in, Indicated in ( represents a positive integer) steps, Indicated in The position vector of the object at the time of step, is an independent and identically distributed random vector, representing the The random displacement vector of the step.

[0084] In step S32, the air resistance of the tiny particles in the gas is also considered. Especially under low Reynolds number conditions, when the particle size is large relative to the gas molecule size, the Stokes-Cunningham drag model (the calculation formula of which is ,in, represents the mean free path of air molecules, which is 69.1 nm at normal temperature and pressure. represents the particle diameter, Represents the base of the natural logarithm), that is, preferably, the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution, including: for simulated particles whose size dimension is larger than the fluid molecules in the respiratory tract, a random walk model and a Stokes-Cunningham drag model are used to simulate the random movement of the corresponding particles in the internal space of the three-dimensional respiratory tract model. In addition, specifically, the correction factor of the Stokes-Cunningham drag model can be set to 1.1737, 1.0579, 1.0347, 1.0248 and 1.0174 respectively according to the particle diameters of 1um, 3um, 5um, 7um and 10um.

[0085] In step S32, Figure 7 and 8As shown, for the model wall boundary conditions, it is particularly necessary to define that when the particle contacts the wall boundary, the particle is considered to be deposited at this position; the end section of the 8th level bronchus is defined as the pressure outlet interface; and the particles passing through the end section of the 8th level bronchus are considered to enter the bronchiolar area and are not included in the subsequent Monte Carlo simulation of passive efficiency scale. In addition, the deposition position is the spatial coordinates (X, Y, Z) of the location where the particle is deposited, and the deposition information may also include the deposition time.

[0086] S4. Import the respiratory tract three-dimensional model into the Monte Carlo simulation software, and add a human tissue three-dimensional model around the respiratory tract three-dimensional model to simulate the scattering and energy attenuation of rays in the soft tissue structure, and also place a Monte Carlo model of the target detector around the human tissue three-dimensional model.

[0087] In step S4, the three-dimensional model of human tissue specifically includes but is not limited to a three-dimensional model of lung tissue, a three-dimensional model of fat layer soft tissue, and a three-dimensional model of skin layer soft tissue. Figure 3 The three-dimensional human tissue model should be composed of tissue equivalent materials, and the detailed components of the relevant tissue equivalent materials are shown in Table 2 below.

[0088] Table 2. Composition of tissue equivalent material elements

[0089]

[0090] The entire model needs to be placed in a vacuum environment close to reality to simulate the ionization of radiation in the air, and the soft tissue should fit the lung tissue as closely as possible. The composition of air is carbon-C: 0.000124, nitrogen-N: 0.755268, oxygen-O: 0.231781, and argon-Ar: 0.012827.

[0091] In step S4, the target detector is a human body irradiation measurement tool to be subjected to passive efficiency calibration, and its Monte Carlo model can be as follows: Figure 4 Specifically, the Monte Carlo model can be placed in the middle of the respiratory tract and about 1 mm to 2 mm away from the outer layer of the soft tissue, as shown in FIG. Figure 5 shown.

[0092] S5. Importing the deposition information into the Monte Carlo simulation software to perform ray emission simulation, and obtaining measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector.

[0093] In the step S5, specifically, the deposition information is imported into the Monte Carlo simulation software for ray emission simulation, including but not limited to: importing the deposition position in the deposition information into the Monte Carlo simulation software as the position where the radioactive aerosol becomes a radiation source and generates radioactive rays after being deposited on the inner wall of the respiratory tract three-dimensional model; and using random trigonometric function equations to simulate and calculate the emission direction of the radioactive rays generated by the radiation source. In order to ensure the accuracy of the simulation experiment, the particle emission rays are simulated for a total of 5,000,000 times in the experiment. At the same time, in order to prevent random errors, the simulation experiment will use the energy of the characteristic X-rays of the radioactive aerosol as the radiation source energy, among which Co-60: 1.33MeV, Cs-137: 0.661MeV. In addition, considering that in actual situations, the detector is generally less efficient in detecting rays irradiated in the human body, and generally requires a considerable amount of time to detect at the same site. For the Monte Carlo simulation, the number of particles needs to be iterated at least millions of times according to the input coordinates before the detector can detect effective information about the particle energy. According to the law of ray penetration, generally γ rays>X rays>α rays or β rays. In simulation experiments, in order to improve operating efficiency, γ rays should be selected as the rays produced when relevant radioactive aerosols decay for simulation experiments.

[0094] In step S5, the specific process of obtaining the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector includes but is not limited to: counting the deposition energy of the ray at the germanium crystal in the Monte Carlo model of the target detector, and drawing a change trend comparison chart according to the change of particle size or the change of particle source energy, such as Fig. 9 shown.

[0095] S6. Based on the measurement data, complete the passive efficiency calibration task for the target detector.

[0096] In the step S6, the specific process of completing the passive efficiency calibration task according to the measurement data is the prior art, for example, obtaining an energy-efficiency curve by energy spectrum comparison.

[0097] Therefore, based on the passive efficiency calibration method for human body irradiation described in the aforementioned steps S1 to S6, a new scheme for improving the passive efficiency calibration for human body irradiation by coupling finite element analysis of multiple physical fields on the basis of traditional Monte Carlo simulation is provided, that is, firstly, a three-dimensional respiratory model of the target human body is reconstructed, and then, according to the physical properties of the fluid in the respiratory tract, the flow field distribution of the fluid inside the three-dimensional respiratory model under the target environment and when the human body breathes is calculated using finite element analysis software, and the movement of the simulated particles under the flow field distribution is calculated to obtain the deposition information of the simulated particles on the inner wall of the respiratory tract, and then the deposition information is imported into the Monte Carlo simulation software for ray emission simulation to obtain the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector, and finally, the passive efficiency calibration task of the detector is completed according to the measurement data. Compared with the traditional scheme, the accuracy of the simulation experiment can be effectively improved by comprehensive calculation of specific model structures, gravity fields, temperature fields and fluid flow fields, and comprehensive experiments can also be carried out for different populations and different detectors, which effectively improves the practicality and facilitates practical application and promotion.

[0098] like Fig.10 As shown, the second aspect of this embodiment provides a virtual device for implementing the method for calibrating the passive efficiency of human body irradiation described in the first aspect, comprising a three-dimensional model reconstruction unit, a flow field distribution calculation unit, a particle motion calculation unit, a simulation model arrangement unit, a ray emission simulation unit and a calibration task completion unit;

[0099] The three-dimensional model reconstruction unit is used to reconstruct a three-dimensional respiratory tract model of the target human body, wherein the three-dimensional respiratory tract model includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main bronchial bifurcation structure sub-model;

[0100] The flow field distribution calculation unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to calculate the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body breathes, using finite element analysis software according to the physical properties of the fluid in the respiratory tract, wherein the fluid in the respiratory tract is a turbulent, constant-temperature and incompressible Newtonian fluid, and the environmental parameters of the target environment include gravity field parameters and temperature field parameters;

[0101] The particle motion calculation unit is communicatively connected to the flow field distribution calculation unit, and is used to add simulated particles having the physical properties of aerosols into the three-dimensional respiratory model, and use the finite element analysis software to calculate the motion of the simulated particles under the flow field distribution condition, and obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes a deposition position or a deposition position and a deposition amount;

[0102] The simulation model arrangement unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to import the three-dimensional respiratory tract model into the Monte Carlo simulation software, and to add a three-dimensional human tissue model for simulating the scattering and energy attenuation of rays in the soft tissue structure around the three-dimensional respiratory tract model, and to place a Monte Carlo model of a target detector around the three-dimensional human tissue model;

[0103] The ray emission simulation unit is respectively connected to the particle motion calculation unit and the simulation model arrangement unit for communication, and is used to import the deposition information into the Monte Carlo simulation software to perform ray emission simulation, and obtain measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector;

[0104] The calibration task completion unit is communicatively connected to the ray emission simulation unit, and is used to complete the passive efficiency calibration task of the target detector according to the measurement data.

[0105] The working process, working details and technical effects of the aforementioned device provided in the second aspect of this embodiment can be referred to the method for calibrating the passive efficiency of in vivo irradiation described in the first aspect, and will not be described in detail here.

[0106] like Fig.11 As shown, the third aspect of this embodiment provides a computer device for executing the passive efficiency calibration method for human body irradiation as described in the first aspect, including a memory, a processor and a transceiver that are sequentially connected in communication, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the passive efficiency calibration method for human body irradiation as described in the first aspect. For example, the memory may include, but is not limited to, a random access memory (Random-Access Memory, RAM), a read-only memory (Read-Only Memory, ROM), a flash memory (Flash Memory), a first-in-first-out memory (First Input First Output, FIFO) and / or a first-in-last-out memory (First Input Last Output, FILO), etc.; the processor may include, but is not limited to, a microprocessor of the STM32F105 series. In addition, the computer device may also include, but is not limited to, a power module, a display screen and other necessary components.

[0107] The working process, working details and technical effects of the aforementioned computer device provided in the third aspect of this embodiment can be referred to the method for calibrating the passive efficiency of human body irradiation described in the first aspect, and will not be described in detail here.

[0108] In a fourth aspect of this embodiment, there is provided a computer-readable storage medium storing instructions including the method for calibrating the passive efficiency of internal human body irradiation as described in the first aspect, that is, the computer-readable storage medium stores instructions, and when the instructions are run on a computer, the method for calibrating the passive efficiency of internal human body irradiation as described in the first aspect is executed. The computer-readable storage medium refers to a carrier for storing data, which may include but is not limited to computer-readable storage media such as floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or memory sticks, and the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0109] The working process, working details and technical effects of the aforementioned computer-readable storage medium provided in the fourth aspect of this embodiment can be referred to the method for calibrating the passive efficiency of in vivo irradiation as described in the first aspect, and will not be described in detail here.

[0110] A fifth aspect of this embodiment provides a computer program product, including a computer program or instructions, wherein when the computer program or instructions are executed by a computer, the method for calibrating the passive efficiency of human body irradiation as described in the first aspect is implemented. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0111] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calibrating passive efficiency of human body irradiation, characterized in that: include: Reconstructing a three-dimensional respiratory model of a target human body specifically includes: acquiring respiratory tract CT data of the target human body; establishing a three-dimensional upper respiratory tract model of the target human body according to the respiratory tract CT data, wherein the three-dimensional upper respiratory tract model includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main trachea sub-model, and in the process of constructing the three-dimensional upper respiratory tract model, according to dosimetry and morphological characteristics of the human respiratory tract, the front end of the nasal cavity is cross-sectioned to ensure that the end face of the nasal cavity is in a geometric coordinate plane, so that it can be used for kinematic finite element simulation during nasal breathing in the later stage, and the oral cavity is constructed into a lip closed state and a mouth slightly open state according to the normal breathing state of the human body, and the lips are segmented into an upper lip. and lower lip, so that the opening angle of the lips can be controlled in the later simulation, simulating the kinematic finite element simulation of mouth breathing of the human body in different states; based on the main trachea sub-model, a multi-level bronchial sub-model connected to the main trachea sub-model and having a left-right symmetrical structure is established, and a main bronchial bifurcation structural sub-model including the main trachea sub-model and the multi-level bronchial sub-model is obtained, and a respiratory tract three-dimensional model of the target human body including the anterior nasal passage sub-model, the posterior nasal passage sub-model, the nose and mouth sub-model, the laryngeal sub-model and the main bronchial bifurcation structural sub-model is obtained, wherein the angle of each bronchial bifurcation of the multi-level bronchial sub-model is rounded with a fillet length of R / 4, and R represents the cross-sectional diameter of the bronchus to which the bronchial bifurcation belongs; According to the physical properties of the fluid in the respiratory tract, the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body is breathing is calculated using finite element analysis software, wherein the physical properties of the fluid in the respiratory tract include fluid density, fluid viscosity, fluid initial velocity, fluid turbulent kinetic energy and fluid turbulent dissipation rate, the fluid in the respiratory tract is a turbulent, constant-temperature and incompressible Newtonian fluid, the environmental parameters of the target environment include gravity field parameters and temperature field parameters, and the flow field distribution includes fluid velocity distribution and fluid pressure distribution; Adding simulated particles with the physical properties of aerosols to the inside of the three-dimensional respiratory model, and using the finite element analysis software to calculate the movement of the simulated particles under the flow field distribution, to obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, specifically including: obtaining initial configuration information of the simulated particles, wherein the simulated particles have the physical properties of aerosols, the initial configuration information includes initial coordinates, initial velocity, particle density, particle diameter and particle mass flow rate, the initial coordinates are at the respiratory inlet cross section of the three-dimensional respiratory model, the initial velocity is consistent with the initial velocity of the fluid in the respiratory tract, and the particle mass flow rate refers to the total mass of particles passing through the respiratory inlet cross section of the three-dimensional respiratory model within one second; adding the simulated particles to the inside of the three-dimensional respiratory model according to the initial configuration information of the simulated particles The method comprises the following steps: calculating the movement of the simulated particles under the flow field distribution using the finite element analysis software, and obtaining the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, wherein the deposition information includes the deposition position or the deposition position and the deposition amount, the deposition position refers to the spatial coordinates of the position where the particle is deposited, and for the model wall boundary condition, it is defined that when the particle contacts the wall boundary, the particle is deemed to be deposited at the position, and when the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution, for the simulated particles whose size dimension is larger than the fluid molecules in the respiratory tract, the random walk model and the Stokes-Cunningham drag model are used to simulate the random movement of the corresponding particles in the internal space of the three-dimensional respiratory model, and the random walk model is expressed as X in the three-dimensional case. n+1 =X n +ε n , n represents a positive integer, X n Indicates the position vector of the object at the nth step, X n+1 represents the position vector of the object at the n+1th step, ε n represents the random displacement vector of the nth step, and the calculation formula of the Stokes-Cunningham drag model is: λ represents the mean free path of air molecules, d represents the particle diameter, e represents the base of the natural logarithm, and the correction factors of the Stokes-Cunningham drag model are set to 1.1737, 1.0579, 1.0347, 1.0248 and 1.0174 respectively according to the particle diameters of 1um, 3um, 5um, 7um and 10um; The respiratory tract three-dimensional model is imported into the Monte Carlo simulation software, and a human tissue three-dimensional model for simulating the scattering and energy attenuation of rays in the soft tissue structure is added around the respiratory tract three-dimensional model, and a Monte Carlo model of a target detector is also placed around the human tissue three-dimensional model, wherein the human tissue three-dimensional model includes a lung tissue three-dimensional model, a fat layer soft tissue three-dimensional model and a skin layer soft tissue three-dimensional model, and the Monte Carlo model is 1mm to 2mm away from the outer layer of the soft tissue; The deposition information is imported into the Monte Carlo simulation software to perform ray emission simulation, and the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector is obtained, wherein the deposition information is imported into the Monte Carlo simulation software to perform ray emission simulation, specifically including: importing the deposition position in the deposition information into the Monte Carlo simulation software as the position where the radioactive aerosol becomes a radiation source and generates radioactive rays after being deposited on the inner wall of the three-dimensional respiratory model; using random trigonometric function equations to simulate and calculate the emission direction of the radioactive rays generated by the radiation source; According to the measurement data, the passive efficiency calibration task of the target detector is completed.

2. A passive efficiency calibration device for human body irradiation, characterized in that: It includes a three-dimensional model reconstruction unit, a flow field distribution calculation unit, a particle motion calculation unit, a simulation model layout unit, a ray emission simulation unit and a calibration task completion unit; The three-dimensional model reconstruction unit is used to reconstruct a three-dimensional respiratory model of the target human body, specifically comprising: acquiring respiratory tract CT data of the target human body; establishing an upper respiratory tract three-dimensional model of the target human body according to the respiratory tract CT data, wherein the upper respiratory tract three-dimensional model includes an anterior nasal passage sub-model, a posterior nasal passage sub-model, a nose and mouth sub-model, a laryngeal sub-model and a main trachea sub-model, and in the process of constructing the upper respiratory tract three-dimensional model, according to dosimetry and the morphological characteristics of the human respiratory tract, the front end of the nasal cavity is cross-sectioned to ensure that the end face of the nasal cavity is in a geometric coordinate plane, so that it can be used for kinematic finite element simulation during nasal breathing in the later stage, and the oral cavity is constructed into a lip closed state and a mouth slightly open state according to the normal breathing state of the human body, and the lips are also divided into two states. The trachea is cut into the upper lip and the lower lip, so that the opening angle of the lips can be controlled in the later simulation, and the kinematic finite element simulation of mouth breathing of the human body in different states is simulated; based on the main trachea sub-model, a multi-level bronchial sub-model connected to the main trachea sub-model and having a left-right symmetrical structure is established, and a main bronchial bifurcation structural sub-model including the main trachea sub-model and the multi-level bronchial sub-model is obtained, and a respiratory tract three-dimensional model of the target human body including the anterior nasal passage sub-model, the posterior nasal passage sub-model, the nose and mouth sub-model, the laryngeal sub-model and the main bronchial bifurcation structural sub-model is obtained, wherein the angle of each bronchial bifurcation of the multi-level bronchial sub-model is rounded with a rounding length of R / 4, and R represents the cross-sectional diameter of the bronchus to which the bronchial bifurcation belongs; The flow field distribution calculation unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to calculate the flow field distribution of the fluid in the respiratory tract inside the three-dimensional model of the respiratory tract under the target environment and when the human body is breathing using finite element analysis software according to the physical properties of the fluid in the respiratory tract, wherein the physical properties of the fluid in the respiratory tract include fluid density, fluid viscosity, fluid initial velocity, fluid turbulent kinetic energy and fluid turbulent dissipation rate, the fluid in the respiratory tract is a turbulent, isothermal and incompressible Newtonian fluid, the environmental parameters of the target environment include gravity field parameters and temperature field parameters, and the flow field distribution includes fluid velocity distribution and fluid pressure distribution; The particle motion calculation unit is communicatively connected to the flow field distribution calculation unit, and is used to add simulated particles with the physical properties of aerosols into the three-dimensional respiratory model, and use the finite element analysis software to calculate the motion of the simulated particles under the flow field distribution, and obtain the deposition information of the simulated particles on the inner wall of the three-dimensional respiratory model, specifically including: obtaining initial configuration information of the simulated particles, wherein the simulated particles have the physical properties of aerosols, and the initial configuration information includes initial coordinates, initial velocity, particle density, particle diameter and particle mass flow rate, the initial coordinates are at the respiratory inlet cross section of the three-dimensional respiratory model, the initial velocity is consistent with the initial velocity of the fluid in the respiratory tract, and the particle mass flow rate refers to the total mass of particles passing through the respiratory inlet cross section of the three-dimensional respiratory model within one second; according to the initial configuration information of the simulated particles, The simulated particles are added to the inside of the three-dimensional model of the respiratory tract, and the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution, and the deposition information of the simulated particles on the inner wall of the three-dimensional model of the respiratory tract is obtained, wherein the deposition information includes the deposition position or the deposition position and the deposition amount, and the deposition position refers to the spatial coordinates of the position where the particle is deposited, and for the model wall boundary condition, it is defined that when the particle contacts the wall boundary, the particle is deemed to be deposited at this position, and when the finite element analysis software is used to calculate the movement of the simulated particles under the flow field distribution, for the simulated particles whose size dimension is larger than the fluid molecules in the respiratory tract, the random walk model and the Stokes-Cunningham drag model are used to simulate the random movement of the corresponding particles in the internal space of the three-dimensional model of the respiratory tract, and the random walk model is expressed as X in three dimensions. n+1 =X n +ε n , n represents a positive integer, X n Indicates the position vector of the object at the nth step, X n+1 represents the position vector of the object at the n+1th step, ε n represents the random displacement vector of the nth step, and the calculation formula of the Stokes-Cunningham drag model is: λ represents the mean free path of air molecules, d represents the particle diameter, e represents the base of the natural logarithm, and the correction factors of the Stokes-Cunningham drag model are set to 1.1737, 1.0579, 1.0347, 1.0248 and 1.0174 respectively according to the particle diameters of 1um, 3um, 5um, 7um and 10um; The simulation model arrangement unit is communicatively connected to the three-dimensional model reconstruction unit, and is used to import the respiratory tract three-dimensional model into the Monte Carlo simulation software, and add a human tissue three-dimensional model for simulating the scattering and energy attenuation of rays in the soft tissue structure around the respiratory tract three-dimensional model, and also place a Monte Carlo model of the target detector around the human tissue three-dimensional model, wherein the human tissue three-dimensional model includes a lung tissue three-dimensional model, a fat layer soft tissue three-dimensional model and a skin layer soft tissue three-dimensional model, and the Monte Carlo model is 1mm to 2mm away from the outer layer of the soft tissue; The ray emission simulation unit is respectively communicatively connected to the particle motion calculation unit and the simulation model arrangement unit, and is used to import the deposition information into the Monte Carlo simulation software to perform ray emission simulation, and obtain the measurement data of the ray at the germanium crystal in the Monte Carlo model of the target detector, wherein the deposition information is imported into the Monte Carlo simulation software to perform ray emission simulation, specifically including: importing the deposition position in the deposition information into the Monte Carlo simulation software as the position where the radioactive aerosol becomes a radiation source and generates radioactive rays after being deposited on the inner wall of the three-dimensional respiratory model; and using random trigonometric function equations to simulate and calculate the emission direction of the radioactive rays generated by the radiation source; The calibration task completion unit is communicatively connected to the ray emission simulation unit, and is used to complete the passive efficiency calibration task of the target detector according to the measurement data.

3. A computer device, characterized in that: It includes a memory, a processor and a transceiver which are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program to execute the passive efficiency calibration method for in vivo irradiation as described in claim 1.

4. A computer-readable storage medium, characterized in that The computer-readable storage medium stores instructions, and when the instructions are executed on a computer, the method for calibrating the passive efficiency of human body irradiation as claimed in claim 1 is executed.

5. A computer program product comprising a computer program or instructions, characterized in that The computer program or the instructions, when executed by a computer, implements the method for calibrating passive efficiency of human body irradiation according to claim 1.

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