Experimental animal organ dose evaluation method based on digital twinning

Abstract

The invention discloses an experimental animal organ dose evaluation method based on digital twinning, and relates to the technical field of radiation dose evaluation, and the method comprises the steps: constructing an experimental animal digital phantom; the digital phantom comprises main organs and tissues of an experimental animal; a digital simulation platform of a microscopic CT system is constructed based on Monte Carlo particle transport simulation, and a radiation transfer process in CT scanning is simulated; constructing a micro-CT dose index phantom, simulating dose detection of the metal oxide semiconductor field effect transistor, and recording an average dose value under a simulation condition; calculating a dose conversion coefficient of the digital simulation platform by comparing a micro-CT dose index result calculated in the digital simulation platform with an actually measured micro-CT dose index result; establishing an organ dose conversion coefficient table; the actual absorbed dose of each organ is calculated; and storing the organ dose data and dose conversion coefficients of different types of experimental animals under different scanning parameters into a database.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation dose assessment, and in particular to a method for assessing organ dose in experimental animals based on digital twins. Background Art

[0002] In radiation medicine and biomedical research, experimental animals are often used to assess radiation doses. However, traditional dose measurement methods have many limitations.

[0003] Traditional thermoluminescent dosimeters (TLDs) and MOSFET sensors can only measure dose at specific points and cannot accurately assess the absorbed dose to an entire organ. Physical phantoms (e.g., made of PMMA) are used for dose measurement in experimental animals, but they are expensive to manufacture and difficult to adapt to animals with different anatomical structures.

[0004] While Monte Carlo simulation can provide highly accurate dose assessments, it is computationally expensive. Furthermore, due to a lack of standardized database support, existing simulations are mostly based on fixed anatomical models, making them difficult to adapt to variations in experimental parameters (tube voltage, field of view, filtration conditions, etc.). The lack of a dose conversion database tailored to different experimental parameters makes it difficult for researchers to quickly and accurately obtain the required dose assessment data in practical applications, hindering the efficient application of Monte Carlo simulations in organ dose assessment in experimental animals. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for evaluating organ dose in experimental animals based on digital twins to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for evaluating organ dose in experimental animals based on digital twins, the method comprising:

[0007] Constructing a digital phantom of an experimental animal; the digital phantom includes the main organs and tissues of the experimental animal; assigning material properties to the main organs and tissues to simulate physical properties;

[0008] The digital phantom of the experimental animal reflects the anatomical structure of the experimental animal, including the position, shape and size of the major organs and tissues;

[0009] A digital simulation platform for micro-CT systems is built based on Monte Carlo particle transport simulation to simulate the physical properties of the X-ray source. The detector and mechanical structure parameters are set through the geometry module to simulate the radiation transmission process during CT scanning.

[0010] Constructing a micro-CT dose index phantom in the digital simulation platform, simulating metal oxide semiconductor field effect transistor dose detection, and recording the average dose value under the simulation conditions;

[0011] Actual micro-CT dose measurements were performed under the same conditions. The dose conversion coefficient of the digital simulation platform was calculated by comparing the micro-CT dose index results calculated in the digital simulation platform with the actual measured micro-CT dose index results.

[0012] Calibrate the digital simulation platform using the digital simulation platform dose conversion coefficient, obtain absorbed dose data of each organ through Monte Carlo simulation calculation, and establish an organ dose conversion coefficient table;

[0013] Calculate the effective tube current value based on the scanning parameters, and calculate the actual absorbed dose of each organ by combining the organ absorbed dose conversion factor;

[0014] Organ dose data and dose conversion coefficients for different types of experimental animals and different scanning parameters are stored in a database. The scanning parameters include tube voltage, field of view size, and filtering conditions.

[0015] According to the above solution, the physical properties of the simulated X-ray source include setting the target material, the ray target angle, the tube voltage parameters and the filtering conditions;

[0016] The detector is constructed by regularly arranged crystal structures; the parameters of the detector include the size of the detector crystals and the number of detector arrays;

[0017] The parameters of the mechanical structure include the distance from the source to the isocenter and the distance from the source to the detector, and the spatial position relationship between the radiation source and the detector in the digital simulation platform is set according to the geometric configuration of the actual micro-CT system.

[0018] According to the above scheme, the construction of the micro-CT dose index phantom includes:

[0019] The diameter of the micro-CT dose index phantom matches the trunk size of the experimental animal, and the axial length covers the longitudinal irradiation range of the CT scan;

[0020] A plurality of dose measurement points are set in the center and edge areas of the micro-CT dose index phantom, and an equivalent model of a metal oxide semiconductor field effect transistor dose detector head is established at each measurement point;

[0021] The number of particles and physical processes of the Monte Carlo simulation are set according to the measurement parameters of the actual measured micro-CT dose index results.

[0022] According to the above solution, the simulated metal oxide semiconductor field effect transistor dose detection and recording of the average dose value under simulation conditions include:

[0023] Positioning the micro-CT dose index phantom at the scanning center in a digital simulation platform, simulating the X-ray beam rotation irradiation process, and recording the energy deposition at each detection point;

[0024] Accumulate the total energy deposition in the complete scanning cycle, calculate and process the dose value, convert the energy deposition into absorbed dose value, and calculate the average dose value of each detection point;

[0025] The dose values ​​of multiple detection points were averaged and normalized to the number of particles per rotation to obtain the micro-CT dose index result of the digital simulation platform.

[0026] According to the above scheme, the dose conversion coefficient of the digital simulation platform is as follows:

[0027]

[0028] Among them, STM represents the dose conversion coefficient of the digital simulation platform; It is expressed as the actual measured micro-CT dose index result; Expressed as the micro-CT dose index result calculated in the simulation platform.

[0029] According to the above scheme, the absorbed dose data of each organ is obtained through Monte Carlo simulation calculation, and an organ dose conversion coefficient table is established, including:

[0030] Loading the experimental animal digital phantom into the calibrated digital simulation platform, setting parameters consistent with actual scanning conditions; running a Monte Carlo simulation to obtain the absorbed dose of each organ in the experimental animal digital phantom;

[0031] Calculate the organ absorbed dose conversion factor, the organ absorbed dose conversion factor is as follows:

[0032]

[0033] Wherein, CF represents the organ absorbed dose conversion factor; STM represents the digital simulation platform dose conversion coefficient; It is expressed as the organ absorbed dose of the digital phantom of the experimental animal in the digital simulation platform;

[0034] The organ absorbed dose conversion factors are calculated for different organs under the same scanning conditions to form an organ dose conversion coefficient table.

[0035] According to the above scheme, the effective tube current value is calculated according to the scanning parameters, and the formula is as follows:

[0036]

[0037] Among them, I eff It is represented by the effective tube current value; T is the scanning time per circle; N is the number of images collected per circle; I SourceIt is expressed as the current size of a single exposure; pitch is expressed as the pitch;

[0038] Combined with the organ absorbed dose conversion factor, the actual absorbed dose of each organ is calculated using the following formula:

[0039] Dose Organ =CF×I eff ;

[0040] Among them, Dose Organ It is expressed as the organ absorbed dose of the experimental animal digital phantom; CF is the organ absorbed dose conversion factor; I eff Expressed as effective tube current value.

[0041] According to the above scheme, the database adopts a hierarchical structure to store data, and the database includes an experimental animal information table, a scanning parameter table and a dose conversion coefficient table;

[0042] The experimental animal information table includes experimental animal species and experimental animal digital phantom parameters; the scanning parameter table includes tube voltage, field of view size, filtration conditions and effective tube current; the dose conversion coefficient table associates animal species with scanning parameters and stores the dose conversion coefficients of each organ;

[0043] The organ absorbed dose data and the corresponding organ absorbed dose conversion factors generated by the Monte Carlo simulation are calibrated with the dose conversion coefficient of the digital simulation platform and stored in the database.

[0044] According to the above scheme, the user inputs experimental parameters, including experimental animal species, tube voltage, field of view size and filtering conditions;

[0045] The database searches for scan protocol records that are completely consistent with the input parameters, obtains the actual absorbed dose of the organ based on the matched organ absorbed dose conversion factor and the effective tube current provided by the user, and outputs an organ dose conversion coefficient table.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The present invention effectively reduces organ dose errors by calibrating the dose conversion coefficient between the digital twin phantom and the digital simulation platform;

[0048] 2. The present invention supports rapid dose prediction under different scanning conditions by establishing an organ dose conversion coefficient table;

[0049] 3. The present invention establishes a database to support rapid matching of scanning protocols and improve efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1This is a flowchart of the steps of the digital twin-based experimental animal organ dose assessment method of the present invention;

[0051] Figure 2 This is a flowchart for estimating the actual absorbed dose of an organ in the digital twin-based experimental animal organ dose assessment method of the present invention;

[0052] Figure 3 This is a three-dimensional reconstruction of a mouse digital phantom for the digital twin-based experimental animal organ dose assessment method of the present invention;

[0053] Figure 4 This is a Monte Carlo simulation dose distribution heat map of the experimental animal organ dose assessment method based on digital twins of the present invention. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] Example: Figures 1-4 As shown, the present invention provides a technical solution, a method for evaluating organ dose in experimental animals based on digital twins, the method comprising:

[0056] S1. Construct a digital phantom of an experimental animal. The digital phantom includes the main organs and tissues of the experimental animal. Material properties are assigned to the main organs and tissues to simulate physical characteristics. The digital phantom of an experimental animal reflects the anatomical structure of the experimental animal, including the location, shape, and size of the main organs and tissues.

[0057] Specifically, for example: the digital phantom is reconstructed based on CT data of real experimental animals, with a voxel resolution of 2mm, accurately reproducing the three-dimensional anatomical structure of 19 major organs, with a position error of less than 1mm; human tissue equivalent materials are used for assignment, for example: bone equivalent is hydroxyapatite, soft tissue equivalent is water equivalent material, and after Monte Carlo simulation verification, the mass density and elemental composition differ from the real tissue by less than 5%; Figure 3As shown in the figure, all the information of the mouse digital phantom is displayed in the form of three-dimensional graphics. Transverse 1 represents the cross-section, showing the distribution status of the tissues and organs of the mouse digital phantom in the cross-section and the proximity of different organs at the same height level; coronal 1 represents the coronal plane, showing the distribution and morphology of the organs in the front-to-back direction of the mouse digital phantom; sagittal 1 represents the sagittal plane, showing the distribution and morphology of the organs in the left-to-right direction of the mouse digital phantom; through the cross-section, coronal and sagittal planes, the morphology, size and position of each tissue and organ in the mouse digital phantom are fully presented from different spatial angles.

[0058] S2. Build a digital simulation platform for micro-CT systems based on Monte Carlo particle transport simulation, simulate the physical properties of the X-ray source, and set detector and mechanical structure parameters through the geometry module to simulate the radiation transmission process in CT scanning;

[0059] Specifically, the SpekPy toolbox is used to generate the X-ray source term. The physical properties of the X-ray source are simulated, including setting the target material, ray target angle, tube voltage parameters and filtering conditions, to improve the accuracy of the simulated X-ray source of micro-CT. The detector is constructed by a regularly arranged crystal structure. The parameters of the detector include the size of the detector crystal and the number of detector arrays. The parameters of the mechanical structure include the distance from the source to the isocenter and the distance from the source to the detector. The ratio of the distance from the source to the isocenter to the distance from the source to the detector determines the magnification ratio, which affects the size of the object area that can be observed by the imaging system and the theoretical limit spatial resolution of the system. According to the geometric configuration of the actual micro-CT system, the spatial position relationship between the radiation source and the detector in the digital simulation platform is set. In the micro-CT digital simulation platform, photons are set as primary particles, and the electromagnetic interaction process is managed by the physical list to simulate the transport process of photons in experimental animal imaging.

[0060] S3. Construct a micro-CT dose index phantom in a digital simulation platform, simulate metal oxide semiconductor field effect transistor dose detection, and record the average dose value under simulation conditions;

[0061] Specifically, the diameter of the micro-CT dose index phantom matches the trunk size of the experimental animal, and the axial length covers the longitudinal irradiation range of the CT scan; multiple dose measurement points are set in the center and edge areas of the micro-CT dose index phantom, and an equivalent model of a metal oxide semiconductor field effect transistor dose detector head is established at each measurement point. For example, the micro-CT dose index phantom is placed at the rotation center of the source and detector, and five cylinders are placed in it to simulate the MOSFET dose detector head; according to the measurement parameters of the actual measured micro-CT dose index results, the particle number and physical process of the Monte Carlo simulation are set.

[0062] Furthermore, the micro-CT dose index phantom was positioned at the scanning center in the digital simulation platform to simulate the X-ray beam rotation irradiation process and record the energy deposition at each detection point. The total energy deposition in the complete scanning cycle was accumulated, and the dose value was calculated and processed. The energy deposition was converted into an absorbed dose value, and the average dose value of each detection point was calculated. The dose values ​​of multiple detection points were averaged and normalized to the number of particles per rotation to obtain the micro-CT dose index result of the digital simulation platform.

[0063] S4. Perform actual micro-CT dose measurement under the same conditions, and calculate the digital simulation platform dose conversion coefficient by comparing the micro-CT dose index result calculated in the digital simulation platform with the actual measured micro-CT dose index result;

[0064] Specifically, since there is a certain difference between the absorbed dose of experimental animals calculated by the digital simulation platform and the actual micro-CT scanning results, the dose conversion coefficient of the digital simulation platform is introduced to correct the error. This difference mainly comes from two aspects: first, there is a deviation between the energy spectrum distribution of the X-ray source in the digital simulation platform and the actual equipment, and second, it is difficult to accurately simulate the effective tube current of the micro-CT during the simulation process, and it is difficult to directly obtain the absorbed dose of experimental animals under the corresponding experimental conditions. Therefore, the simulation results are corrected by the dose conversion coefficient of the digital simulation platform to make it closer to the actual micro-CT scanning conditions. The formula of the dose conversion coefficient of the digital simulation platform is as follows:

[0065]

[0066] Among them, STM represents the dose conversion coefficient of the digital simulation platform; It is expressed as the actual measured micro-CT dose index result, that is, the absorbed dose of the experimental object under the condition of equivalent attenuation of the micro-CT dose index phantom; Expressed as the micro-CT dose index result calculated in the simulation platform.

[0067] S5. Calibrate the digital simulation platform using the dose conversion coefficient of the digital simulation platform, obtain absorbed dose data for each organ through Monte Carlo simulation, and establish an organ dose conversion coefficient table;

[0068] Specifically, the experimental animal digital phantom is loaded into the calibrated digital simulation platform, and parameters consistent with actual scanning conditions are set; a Monte Carlo simulation is run to obtain the absorbed dose of each organ in the experimental animal digital phantom;

[0069] Furthermore, the organ absorbed dose conversion factor is calculated. The organ absorbed dose conversion factor is as follows:

[0070]

[0071] Wherein, CF represents the organ absorbed dose conversion factor; STM represents the digital simulation platform dose conversion coefficient; It is expressed as the absorbed dose of organs of the digital phantom of experimental animals in the digital simulation platform;

[0072] Furthermore, organ absorbed dose conversion factors are calculated for different organs under the same scanning conditions to form an organ dose conversion coefficient table.

[0073] S6. Calculate the effective tube current value based on the scanning parameters and, combined with the organ absorbed dose conversion factor, estimate the actual absorbed dose of each organ;

[0074] Specifically, the effective tube current value is calculated according to the scanning parameters, and the formula is as follows:

[0075]

[0076] Among them, I eff It is represented by the effective tube current value; T is the scanning time per circle; N is the number of images collected per circle; I Source It is expressed as the current size of a single exposure; pitch is expressed as the pitch;

[0077] Furthermore, the actual absorbed dose of each organ is calculated by combining the organ absorbed dose conversion factor. The formula is as follows:

[0078] Dose Organ =CF×I eff ;

[0079] Among them, Dose Organ It is expressed as the organ absorbed dose of the experimental animal digital phantom; CF is the organ absorbed dose conversion factor; I eff It is expressed as the effective tube current value; for example, the experimental animal digital phantom contains 19 organs, so the absorbed dose results of 19 organs can be obtained, such as Figure 4 As shown in the figure, a Monte Carlo simulation dose distribution heat map is generated. Transverse1 represents the transverse plane, showing the dose distribution of different tissues and organs on the cross-section of the mouse digital phantom, and presenting the dose differences between adjacent organs on the same cross-section. Coronal1 represents the coronal plane, showing the dose distribution and differential morphology of each organ in the anterior-posterior direction of the mouse digital phantom, showing the increase and decrease of dose in the anterior-posterior direction. Sagittal1 represents the sagittal plane, showing the dose distribution and morphology of each organ in the lateral direction of the mouse digital phantom, showing the high and low distribution of dose in the lateral direction. Through the transverse, coronal, and sagittal planes, the dose distribution morphology, high and low differences, and spatial position of each tissue and organ in the mouse digital phantom under Monte Carlo simulation are fully presented from different spatial angles.

[0080] S7. storing organ dose data and dose conversion coefficients for different types of experimental animals and different scanning parameters in a database, where the scanning parameters include tube voltage, field of view size, and filtering conditions;

[0081] Specifically, the database uses a hierarchical structure to store data, and the database includes an experimental animal information table, a scanning parameter table and a dose conversion coefficient table; the experimental animal information table includes the experimental animal species and the experimental animal digital phantom parameters; the scanning parameter table includes the tube voltage, field of view size, filtration conditions and effective tube current; the dose conversion coefficient table associates the animal species with the scanning parameters and stores the dose conversion coefficient of each organ; the organ absorption dose data generated by the Monte Carlo simulation and the corresponding organ absorption dose conversion factor are calibrated with the dose conversion coefficient of the digital simulation platform and stored in the database.

[0082] Furthermore, the user inputs experimental parameters, including the type of experimental animal, tube voltage, field of view size, and filtration conditions; the database searches for scan protocol records that are completely consistent with the input parameters, obtains the actual absorbed dose of the organ based on the matched organ absorbed dose conversion factor and the effective tube current provided by the user, and outputs an organ dose conversion coefficient table.

[0083] The present invention provides another technical solution, a method for evaluating organ dose in experimental animals based on digital twins;

[0084] A 45g digital mouse phantom was constructed. The phantom includes major organs such as the skin, lungs, liver, stomach, spleen, intestines, and bladder. Constructed with a voxel resolution of 2mm, the phantom accurately reproduces the anatomical structure of the experimental animal, including the position, shape, and size of major organs and tissues. Positional error is less than 1mm, ensuring high consistency between the model and the real animal.

[0085] Human tissue-equivalent materials were used to assign corresponding properties to various parts of the mouse digital phantom. For example, bones were assigned hydroxyapatite, and soft tissues were assigned water-equivalent materials. Monte Carlo simulations verified that the mass density and elemental composition of each part of the mouse digital phantom under this assignment method differed from real tissue by less than 5%, effectively ensuring that the physical properties of the mouse digital phantom in radiation simulations were similar to those of real animals.

[0086] A digital simulation platform for the micro-CT system was constructed based on Monte Carlo particle transport simulation. The target material was set to tungsten, the tube voltage parameter was set to 70 kV, the filtration condition was set to 0.5 mm aluminum filter, and the number of particles in the Monte Carlo simulation was set to 1.5×10 8 photons / angle;

[0087] When performing Monte Carlo simulation, the scanning parameters were set as follows: 2160 projection angles were collected in one circle, the single exposure current was 200 μA, the exposure time was 80 ms, and the pitch was 0.5;

[0088] According to the scanning parameters, calculate the effective tube current value:

[0089] I eff =80ms×2160×200μA / 0.5=69.12mAs;

[0090] The effective tube current value takes into account the exposure time, projection angle and pitch factors;

[0091] The user enters the experimental parameters, and the database will accurately search and match the input parameters, output the corresponding organ dose conversion coefficient table, and combine the scanning parameters to calculate and output the actual absorbed dose of each organ, as shown in Table 1:

[0092] Organ name CF Organ dose (μGy) Skin / thyroid 4.61 318.89 lung 3.43 237.08 liver 3.70 256.02 Stomach 3.83 264.58 spleen 4.16 287.47 Intestinal 4.05 279.71 bladder 3.94 272.36

[0093] Table 1: Actual absorbed doses to various organs

[0094] Table 1 only shows the actual absorbed dose calculation results of some organs. This is only for illustration and not for limitation.

[0095] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for evaluating organ dose in experimental animals based on digital twins, characterized by: The method includes: Constructing a digital phantom of an experimental animal; the digital phantom includes the main organs and tissues of the experimental animal; assigning material properties to the main organs and tissues to simulate physical properties; the digital phantom of the experimental animal reflects the anatomical structure of the experimental animal, the anatomical structure including the position, shape and size of the main organs and tissues; A digital simulation platform for micro-CT systems is built based on Monte Carlo particle transport simulation to simulate the physical properties of the X-ray source. The detector and mechanical structure parameters are set through the geometry module to simulate the radiation transmission process during CT scanning. Constructing a micro-CT dose index phantom in the digital simulation platform, simulating metal oxide semiconductor field effect transistor dose detection, and recording the average dose value under the simulation conditions; Actual micro-CT dose measurements were performed under the same conditions. The dose conversion coefficient of the digital simulation platform was calculated by comparing the micro-CT dose index results calculated in the digital simulation platform with the actual measured micro-CT dose index results. Calibrate the digital simulation platform using the digital simulation platform dose conversion coefficient, obtain absorbed dose data of each organ through Monte Carlo simulation calculation, and establish an organ dose conversion coefficient table; Calculate the effective tube current value based on the scanning parameters, and calculate the actual absorbed dose of each organ by combining the organ absorbed dose conversion factor; Organ dose data and dose conversion coefficients for different types of experimental animals and different scanning parameters are stored in a database. The scanning parameters include tube voltage, field of view size, and filtering conditions.

2. The method for experimental animal organ dose assessment based on digital twins according to claim 1, characterized in that: The physical properties of the simulated X-ray source include setting target materials, ray target angles, tube voltage parameters and filtering conditions; The detector is constructed by regularly arranged crystal structures; the parameters of the detector include the size of the detector crystals and the number of detector arrays; The parameters of the mechanical structure include the distance from the source to the isocenter and the distance from the source to the detector, and the spatial position relationship between the radiation source and the detector in the digital simulation platform is set according to the geometric configuration of the actual micro-CT system.

3. The method for experimental animal organ dose assessment based on digital twins according to claim 1, characterized in that: The method of constructing a micro-CT dose index phantom comprises: The diameter of the micro-CT dose index phantom matches the trunk size of the experimental animal, and the axial length covers the longitudinal irradiation range of the CT scan; A plurality of dose measurement points are set in the center and edge areas of the micro-CT dose index phantom, and an equivalent model of a metal oxide semiconductor field effect transistor dose detector head is established at each measurement point; The number of particles and physical processes of the Monte Carlo simulation are set according to the measurement parameters of the actual measured micro-CT dose index results.

4. The method for experimental animal organ dose assessment based on digital twins according to claim 3, characterized in that: The simulated metal oxide semiconductor field effect transistor dose detection records the average dose value under the simulation conditions, including: Positioning the micro-CT dose index phantom at the scanning center in a digital simulation platform, simulating the X-ray beam rotation irradiation process, and recording the energy deposition at each detection point; Accumulate the total energy deposition in the complete scanning cycle, calculate and process the dose value, convert the energy deposition into absorbed dose value, and calculate the average dose value of each detection point; The dose values ​​of multiple detection points were averaged and normalized to the number of particles per rotation to obtain the micro-CT dose index result of the digital simulation platform.

5. The method for experimental animal organ dose assessment based on digital twins according to claim 1, characterized in that: The dose conversion coefficient of the digital simulation platform is as follows: Among them, STM represents the dose conversion coefficient of the digital simulation platform; It is expressed as the actual measured micro-CT dose index result; Expressed as the micro-CT dose index result calculated in the simulation platform.

6. The method for experimental animal organ dose assessment based on digital twins according to claim 1, characterized in that: The Monte Carlo simulation calculation is used to obtain the absorbed dose data of each organ and establish an organ dose conversion coefficient table, including: Loading the experimental animal digital phantom into the calibrated digital simulation platform, setting parameters consistent with actual scanning conditions; running a Monte Carlo simulation to obtain the absorbed dose of each organ in the experimental animal digital phantom; Calculate the organ absorbed dose conversion factor, the organ absorbed dose conversion factor is as follows: Wherein, CF represents the organ absorbed dose conversion factor; STM represents the digital simulation platform dose conversion coefficient; It is expressed as the absorbed dose of organs of the digital phantom of experimental animals in the digital simulation platform; The organ absorbed dose conversion factors are calculated for different organs under the same scanning conditions to form an organ dose conversion coefficient table.

7. The method for experimental animal organ dose assessment based on digital twins according to claim 6, characterized in that: According to the scanning parameters, the effective tube current value is calculated as follows: Among them, I eff It is represented by the effective tube current value; T is the scanning time per circle; N is the number of images collected per circle; I Source It is expressed as the current size of a single exposure; pitch is expressed as the pitch; Combined with the organ absorbed dose conversion factor, the actual absorbed dose of each organ is calculated using the following formula: Dose Organ =CF×I eff ; Among them, Dose Organ It is expressed as the organ absorbed dose of the experimental animal digital phantom; CF is the organ absorbed dose conversion factor; I eff Expressed as effective tube current value.

8. The method for experimental animal organ dose assessment based on digital twins according to claim 1, characterized in that: The database uses a hierarchical structure to store data, and the database includes an experimental animal information table, a scanning parameter table, and a dose conversion coefficient table; The experimental animal information table includes experimental animal species and experimental animal digital phantom parameters; the scanning parameter table includes tube voltage, field of view size, filtration conditions and effective tube current; the dose conversion coefficient table associates animal species with scanning parameters and stores the dose conversion coefficients of each organ; The organ absorbed dose data and the corresponding organ absorbed dose conversion factors generated by the Monte Carlo simulation are calibrated with the dose conversion coefficient of the digital simulation platform and stored in the database.

9. The method for experimental animal organ dose assessment based on digital twins according to claim 8, characterized in that: The user inputs experimental parameters, including experimental animal species, tube voltage, field of view size, and filtering conditions; The database searches for scan protocol records that are completely consistent with the input parameters, obtains the actual absorbed dose of the organ based on the matched organ absorbed dose conversion factor and the effective tube current provided by the user, and outputs an organ dose conversion coefficient table.

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