Preparation method of neck-thyroid phantom and neck-thyroid phantom

Abstract

The embodiment of the invention provides a preparation method of a neck-thyroid phantom. The preparation method comprises the following steps: preparing photosensitive resin containing radioactive isotopes; and preparing a thyroid body source containing photosensitive resin and a neck model matched with the thyroid body source. The activity of the thyroid body source is valued through a mass method. And assembling the thyroid body source with the fixed value and the neck model to form a neck-thyroid body model. The neck-thyroid phantom prepared by the preparation method provided by the embodiment of the invention can improve the reliability of a detector calibration result.

Description

Technical Field

[0001] The present application relates to the technical field of radioactive measurement, and particularly relates to a preparation method of a neck-thyroid phantom and a neck-thyroid phantom. Background Art

[0002] In many fields of nuclear energy application, radioactive measurement is a basic and key technology. With the continuous progress of nuclear technology, the requirements for the efficiency of detectors are also continuously increasing. The detection efficiency of a detector is related to the solid angle subtended by the source at the detector, that is, related to the size of the source and the distance between the source and the detector. In nuclear-related fields such as nuclear industry manufacturing, reactor operation, and nuclear fuel reprocessing, the formation of radioactive gases and aerosols is a common phenomenon. These substances may enter the human body through the respiratory or digestive system and deposit in key organs such as the lungs, thyroid gland, and bones. Currently, the standard sources used for detector calibration are usually point sources or volume sources with regular geometric shapes, which cannot accurately simulate the measurement of radioactivity in human organs in nuclear medicine or nuclear emergencies. In order to achieve more precise efficiency calibration and ensure the accuracy and reliability of measurement results, the demand for heterogeneous volume sources that can simulate the geometric shape of the source to be measured is increasing.

[0003] However, the standard sources for detector calibration in related technologies cannot accurately simulate the measurement of radioactivity in human organs, resulting in relatively low reliability of the detector efficiency calibration results. Summary of the Invention

[0004] In view of this, the main purpose of the embodiments of the present application is to provide a preparation method of a neck-thyroid phantom and a neck-thyroid phantom that can improve the reliability of detector efficiency calibration results.

[0005] To achieve the above object, the technical solution of the embodiments of the present application is implemented as follows:

[0006] On the one hand, the embodiments of the present application provide a preparation method of a neck-thyroid phantom, and the preparation method includes the following steps:

[0007] Prepare a photosensitive resin containing a radioactive isotope;

[0008] Prepare a thyroid volume source containing the photosensitive resin and a neck model matching it;

[0009] Determine the activity of the thyroid volume source by the mass method;

[0010] Assemble the thyroid volume source after activity determination with the neck model to form the neck-thyroid phantom.

[0011] In one implementation, the preparation of the photosensitive resin containing a radioactive isotope specifically includes:

[0012] The radioactive isotope is doped into the photosensitive resin by a phase transfer method.

[0013] In one embodiment, doping the radioactive isotope into the photosensitive resin by the phase transfer method specifically includes:

[0014] Determine the type and dosage of the phase transfer agent, the addition amount of the radioactive isotope, and the mixing time according to the radioactive isotope, and mix the phase transfer agent, the radioactive isotope, and the photosensitive resin to form a photosensitive resin containing the radioactive isotope.

[0015] In one embodiment, the phase transfer agent is an extractant for the radioactive isotope;

[0016] The radioactive isotope is 131 I, and the phase transfer agent includes one of tri-n-octylamine extractant, dimethyl sulfoxide extractant, and N,N-dimethylformamide extractant; or,

[0017] The radioactive isotope is 152 Eu, and the phase transfer agent includes one of P507 extractant, P204 extractant, and TBP extractant.

[0018] In one embodiment, the mixing time is greater than or equal to 0.5 h and less than or equal to 24 h.

[0019] In one embodiment, preparing the thyroid phantom containing the photosensitive resin and its matching neck model specifically includes:

[0020] Obtain the anatomical data of the thyroid gland, generate a three-dimensional model of the thyroid gland by three-dimensional reconstruction technology, and design the matching neck model;

[0021] Using the photosensitive resin containing the radioactive isotope as the raw material, print the thyroid phantom with a photocuring 3D printer;

[0022] Using ordinary commercial photosensitive resin as the raw material, print the neck model with a photocuring 3D printer.

[0023] In one embodiment, the adjustable range of the exposure light intensity of the photocuring 3D printer is greater than or equal to 60% and less than or equal to 100%; and / or,

[0024] The exposure time of the photocuring 3D printer is greater than or equal to 3.5 s and less than or equal to 4.5 s.

[0025] In one embodiment, determining the activity of the thyroid phantom by the mass method specifically includes:

[0026] Using the photosensitive resin containing the radioactive isotope as the raw material, a plurality of cylindrical volume sources are printed by a stereolithography 3D printer;

[0027] The cylindrical volume source is calibrated by a high-purity germanium γ spectrometer;

[0028] The activity concentration per unit mass of the cylindrical volume source is obtained;

[0029] The activity of the thyroid volume source is calibrated according to the activity concentration per unit mass of the cylindrical volume source.

[0030] In one embodiment, the assembling the calibrated thyroid volume source with the neck model to form the neck-thyroid phantom specifically includes:

[0031] Coating the calibrated thyroid volume source with at least one of a heat-shrinkable film or a food wrap;

[0032] Placing the sealed thyroid volume source in the accommodation cavity of the neck model.

[0033] Another aspect of the embodiments of the present application provides a neck-thyroid phantom, which is prepared by the preparation method described in any one of the above, and the neck-thyroid phantom includes:

[0034] A thyroid volume source;

[0035] A neck model having an accommodation cavity, and the thyroid volume source is located in the accommodation cavity.

[0036] The embodiments of the present application provide a preparation method of a neck-thyroid phantom and a neck-thyroid phantom. The preparation method includes the following steps: configuring a photosensitive resin containing a radioactive isotope. Preparing a thyroid volume source containing the photosensitive resin and a matching neck model. Calibrating the activity of the thyroid volume source by the mass method. Assembling the calibrated thyroid volume source with the neck model to form a neck-thyroid phantom. The thyroid volume source prepared by using the photosensitive resin mixed with the radioactive isotope as the raw material has a density and composition that can be close to the real volume source. Therefore, the phantom prepared by this preparation method can have a high precision, can better simulate the measurement of radioactivity in human organs, and thus make the detector efficiency calibration result more accurate and reliable. Description of the Drawings

[0037] Figure 1 It is a flowchart of a preparation method of a neck-thyroid phantom according to an embodiment of the present application;

[0038] Figure 2 It is a structural schematic diagram of a neck-thyroid phantom according to an embodiment of the present application;

[0039] Figure 3 For Figure 2 the sectional view taken along A-A in

[0040] Description of the reference numerals in the drawings

[0041] 10. Neck-thyroid phantom; 11. Thyroid source; 12. Neck model. Specific embodiments

[0042] Reference to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0043] In the description of the embodiments of the present application, unless otherwise clearly defined and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0044] An embodiment of the present application provides a method for preparing a neck-thyroid phantom 10. Please refer to Figure 1 , and the preparation method includes the following steps:

[0045] Step S1: Configure a photosensitive resin containing a radioactive isotope.

[0046] Step S2: Prepare a thyroid source 11 containing the photosensitive resin and a neck model 12 matching it.

[0047] Step S3: Determine the activity of the thyroid source 11 by the mass method.

[0048] Step S4: Assemble the thyroid source 11 with the determined activity and the neck model 12 to form a neck-thyroid phantom 10.

[0049] Specifically, the thyroid source 11 refers to a thyroid model made of a photosensitive resin containing a radioactive isotope and can provide a calibration source for the detector.

[0050] The shape of the thyroid gland source 11 is similar to that of the real thyroid gland. That is to say, the thyroid gland source 11 can completely restore the shape of the real thyroid gland, thereby avoiding the influence on the detection efficiency of the detector due to the shape problem.

[0051] The neck model 12 refers to a component that simulates the shape of the human neck and provides an installation space for the thyroid gland source 11.

[0052] The size of the neck model 12 is not limited.

[0053] For example, the neck model 12 is a cylindrical model with a diameter of 120 mm and a height of 120 mm.

[0054] The type of radioactive isotope is not limited.

[0055] For example, the radioactive isotope is 131 I.

[0056] Another example, the radioactive isotope is 152 Eu.

[0057] The method of doping with radioactive isotopes is not limited.

[0058] For example, the radioactive isotope is doped into the photosensitive resin by the phase transfer method.

[0059] Specifically, most of the compounds of radionuclides are soluble in water, and the photosensitive resin for preparing the thyroid gland source 11 is an organic substance. In the related art, the radionuclide can be mixed in the photosensitive resin by modifying the photosensitive resin or the radionuclide. In this embodiment, the radionuclide is transferred from the aqueous phase to the organic phase by the phase transfer method, so that the radionuclide can be stably and uniformly distributed in the photosensitive resin. The phase transfer method can be carried out at room temperature, thereby simplifying the experimental operation and reducing the preparation difficulty.

[0060] The preparation method of the neck-thyroid gland phantom 10 in the embodiment of the present application includes the following steps: configuring a photosensitive resin containing a radioactive isotope; preparing a thyroid gland source 11 containing the photosensitive resin and a matching neck model 12; determining the activity of the thyroid gland source 11 by the mass method; assembling the thyroid gland source 11 with the determined activity and the neck model 12 to form the neck-thyroid gland phantom 10. Thus, the thyroid gland source 11 prepared from the photosensitive resin mixed with the radioactive isotope has a density and composition close to that of the real source. Therefore, the phantom prepared by this preparation method has high precision and can better simulate the measurement of radioactivity in human organs, thereby making the detector efficiency calibration result more accurate and reliable.

[0061] In one embodiment, doping the radioactive isotope into the photosensitive resin by the phase transfer method specifically includes:

[0062] Determine the type, dosage, addition amount of the radioactive isotope, and mixing time of the phase transfer agent, and mix the phase transfer agent, radioactive isotope, and photosensitive resin to form a photosensitive resin containing the radioactive isotope. Thereby, the radioactive isotope can be uniformly and stably dispersed in the photosensitive resin, thereby improving the accuracy and reliability of the calibration result.

[0063] Specifically, the phase transfer agent refers to a substance that can interact with a radioactive isotope such that the radioactive element can be transferred from the aqueous phase to the organic phase (photosensitive resin).

[0064] The type of the phase transfer agent is determined according to the type of the radioactive isotope.

[0065] Exemplarily, the phase transfer agent is an extractant for the radioactive isotope. The radioactive isotope is 131 I, and the phase transfer agent includes one of tri-n-octylamine extractant, dimethyl sulfoxide extractant, and N,N-dimethylformamide extractant.

[0066] Exemplarily, the phase transfer agent is an extractant for the radioactive isotope. The radioactive isotope is 152 Eu, and the phase transfer agent includes one of P507 extractant (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester), P204 extractant (bis(2-ethylhexyl) phosphate), and TBP extractant (tributyl phosphate).

[0067] In one embodiment, the mixing time is greater than or equal to 0.5 h and less than or equal to 24 h. For example, the mixing time is 0.5 h, 2 h, 5 h, 10 h, 15 h, or 24 h. Keeping the mixing time within the above range can make the radioactive isotope uniformly and stably dispersed in the photosensitive resin, thereby improving the accuracy and reliability of the calibration result.

[0068] In one specific embodiment, the radioactive element is 131 I, the phase transfer agent is tri-n-octylamine extractant, isopentanol is used as a diluent for the phase transfer agent, the volume ratio of tri-n-octylamine to isopentanol in the phase transfer agent is 1:1, the mass ratio of the phase transfer agent to the photosensitive resin is greater than or equal to 0.01 and less than or equal to 0.05, 131 the addition amount of I is greater than or equal to 400 mg / kg and less than or equal to 700 mg / kg. The mixing time of the phase transfer agent, radioactive isotope, and photosensitive resin is greater than or equal to 2 h and less than or equal to 24 h. Thereby, the 131 transfer efficiency of I can be improved, and further the 131 stability of I in the photosensitive resin can be improved.

[0069] In a specific embodiment, the mass ratio of the phase transfer agent to the photosensitive resin is greater than or equal to 0.02 and less than or equal to 0.04. For example, the mass ratio of the phase transfer agent to the photosensitive resin is 0.02, 0.03 or 0.04. Keeping the mass ratio of the phase transfer agent to the photosensitive resin within the above range can further improve 131 the transfer efficiency of I.

[0070] In a specific embodiment, 131 the addition amount of I is greater than or equal to 500 mg / kg and less than or equal to 600 mg / kg. For example, 131 the addition amount of I is 500 mg / kg, 600 mg / kg or 700 mg / kg. Thus, keeping the addition amount of I within the above range can further improve 131 the uniformity and transfer efficiency of I. 131 I.

[0071] Specifically, 131 the activity range of I is not limited.

[0072] For example, 131 the activity range of I is greater than or equal to 1E+3 Bq and less than or equal to 1E+6 Bq. Thus, it is convenient for the detector to obtain sufficient counts, thereby improving the accurate calibration of the detector efficiency.

[0073] In a specific embodiment, 131 the activity range of I is greater than or equal to 10 Bq and less than or equal to 1E+8 Bq.

[0074] In a specific embodiment, the mixing time of the phase transfer agent, the radioactive isotope and the photosensitive resin is greater than or equal to 2 h and less than or equal to 4 h. For example, the mixing time of the phase transfer agent, the radioactive isotope and the photosensitive resin is 2 h, 3 h or 4 h. Thus, keeping the mixing time within the above range can, on the one hand, enable the phase transfer agent to have sufficient time to evenly disperse the radioactive isotope in the photosensitive resin, improving the uniformity of the distribution of the radioactive isotope in the photosensitive resin. On the other hand, it can save the mixing time of the phase transfer agent, the radioactive isotope and the photosensitive resin and improve the experimental efficiency.

[0075] In one embodiment, the preparation of the thyroid phantom 11 containing the photosensitive resin and the matching neck model 12 specifically includes:

[0076] Obtain the anatomical data of the thyroid gland, generate a three-dimensional model of the thyroid gland using three-dimensional reconstruction technology, and design a matching neck model 12.

[0077] Using the photosensitive resin containing the radioactive isotope as the raw material, print the thyroid phantom 11 using a photocuring 3D printer.

[0078] Using ordinary commercial photosensitive resin as raw material, a neck model 12 is printed by a stereolithography 3D printer.

[0079] Thus, on the one hand, the three-dimensional model of the thyroid gland can highly restore the true size and shape of the human thyroid gland, more realistically simulate the diffusion state of radionuclides in human organs, reduce the error in the detector efficiency calibration caused by the shape of the source, and further improve the accuracy and reliability of the measurement results of the calibrated instrument. On the other hand, by using photosensitive resin containing radioactive isotopes and ordinary commercial photosensitive resin to print the thyroid phantom 11 and the neck model 12 respectively, it not only meets the radioactive requirements for the detector calibration of the thyroid phantom 11, but also avoids the interference of the neck model 12 on radioactive measurement, further improving the reliability and effectiveness of the calibration.

[0080] Specifically, 3D printing technology can produce human models with fine structures. Compared with the subtractive manufacturing technology in related technologies, it avoids waste and pollution generated during the processing, and has the characteristics of high efficiency and cleanliness. Precise geometric data of human organs are obtained through computed tomography (CT), and the data are analyzed using software such as MATLAB to construct a 3D model. By using a stereolithography 3D printer to print human organs and other non-regularly shaped radioactive phantoms, the shape and size of the radioactive phantoms can be adjusted at any time according to the actual application situation. By adjusting the 3D model of the phantom, radioactive phantoms of different shapes and sizes can be prepared, thus improving the flexibility of the preparation of radioactive phantoms.

[0081] In addition, by using liquid photosensitive resin as the base material of the thyroid phantom 11, on the one hand, the density and composition of the thyroid phantom 11 can be closer to the real phantom, and on the other hand, the doping difficulty of radioactive isotopes is reduced.

[0082] The method of obtaining the anatomical data of the thyroid gland is not limited.

[0083] For example, the anatomical data of the thyroid gland are obtained from CT medical images, Chinese digital atlases, and anatomy.

[0084] Using the obtained anatomical data of the thyroid gland and three-dimensional reconstruction technology, the segmented two-dimensional image data of the thyroid gland are converted into three-dimensional volume data to generate a three-dimensional model of the thyroid gland. Thus, the three-dimensional model of the thyroid gland can be made more in line with the actual situation.

[0085] Ordinary commercial photosensitive resin refers to photosensitive resin that does not contain radioactive isotopes.

[0086] By adjusting the exposure light intensity and exposure time of the stereolithography 3D printer, the curing degree of the photosensitive resin is adjusted so that the photosensitive resin containing radioactive isotopes can be completely cured.

[0087] Exemplarily, the adjustable range of the exposure light intensity of the stereolithography 3D printer is greater than or equal to 60% and less than or equal to 100%. For example, the exposure light intensity of the stereolithography 3D printer is 60%, 70%, 80%, 90% or 100%. Thus, on the one hand, the risk of deformation of the thyroid phantom 11 caused by insufficient exposure light intensity resulting in incomplete curing of the photosensitive resin can be avoided. On the other hand, the risk of cracking or damage of the thyroid phantom 11 caused by excessive exposure light intensity resulting in over-curing of the photosensitive resin can be avoided.

[0088] Exemplarily, the exposure time of the stereolithography 3D printer is greater than or equal to 3.5 s and less than or equal to 4.5 s. For example, the exposure time of the stereolithography 3D printer is 3.5 s, 4 s or 4.5 s. Thus, on the one hand, the risk of deformation of the thyroid phantom 11 caused by insufficient exposure time resulting in incomplete curing of the photosensitive resin can be avoided. On the other hand, the risk of cracking or damage of the thyroid phantom 11 caused by excessive exposure time resulting in over-curing of the photosensitive resin can be avoided.

[0089] Specifically, there is no limit to the adjustment unit of the exposure time.

[0090] For example, the adjustment unit of the exposure time is 0.5 s.

[0091] In one embodiment, the activity determination of the thyroid phantom 11 by the mass method specifically includes:

[0092] Using the photosensitive resin containing radioactive isotopes as the raw material, printing a plurality of cylindrical phantoms with a stereolithography 3D printer.

[0093] Determining the value of the cylindrical phantom by a high-purity germanium γ spectrometer.

[0094] Obtaining the activity concentration per unit mass of the cylindrical phantom.

[0095] Determining the activity of the thyroid phantom 11 according to the activity concentration per unit mass of the cylindrical phantom.

[0096] Specifically, while printing the thyroid phantom 11 with a stereolithography 3D printer, print a plurality of cylindrical phantoms to determine the activity of the thyroid phantom 11 by the activity per unit mass of the cylindrical phantom.

[0097] There is no limit to the number of cylindrical phantoms.

[0098] For example, the number of cylindrical phantoms is 20. Thus, by measuring the activity per unit mass of a plurality of cylindrical phantoms, the influence of errors in the measurement process on the experimental results can be reduced, thereby improving the accuracy of obtaining the activity of the thyroid phantom 11.

[0099] The printing method of the cylindrical body source is not limited.

[0100] For example, the cylindrical body source is printed with a vertical placement.

[0101] Also, for example, the cylindrical body source is printed with a horizontal placement.

[0102] Furthermore, some of the cylindrical body sources are printed with a vertical placement, and the other part of the cylindrical body sources are printed with a horizontal placement. Thus, by measuring the activity per unit mass of the cylindrical body sources printed with a vertical placement and a horizontal placement respectively, the uniformity of the photosensitive resin can be evaluated, and thus the accuracy of the activity acquisition of the thyroid body source 11 can be further improved.

[0103] In a specific embodiment, 20 cylindrical body sources are printed using a stereolithography 3D printer, among which 12 are printed with a vertical placement and 8 are printed with a horizontal placement. The mass and counting rate of the cylindrical body sources are measured respectively, and the relative standard deviation of the cylindrical body sources is calculated at the same time. The one-way analysis of variance method is used to test whether there are significant differences in printing in the horizontal and vertical directions, so as to evaluate the uniformity of the photosensitive resin containing radioactive isotopes, and further verify the accuracy of the measurement by the mass method. The measurement results of the cylindrical body sources are shown in Table 1. The analysis of variance results of the cylindrical body sources are shown in Table 2.

[0104] Table 1 Measurement Results of Cylindrical Body Sources

[0105] Sample number Mass / g <![CDATA[Net count rate / s -1 > <![CDATA[Net count rate per gram / s -1 > 1 13.28 39.47 2.97 2 13.27 38.38 2.89 3 13.28 38.72 2.92 4 13.28 39.03 2.94 5 13.28 37.63 2.83 6 13.23 38.48 2.91 7 13.29 37.90 2.85 8 13.27 38.16 2.88 9 13.26 38.42 2.90 10 13.26 38.29 2.89 11 13.30 39.14 2.94 12 13.29 37.53 2.82 13 13.36 38.99 2.92 14 13.39 38.78 2.90 15 13.33 38.62 2.90 16 13.37 39.23 2.93 17 13.39 38.00 2.84 18 13.40 38.19 2.85 19 13.34 38.03 2.85 20 13.38 39.06 2.92

[0106] Table 2 Analysis of Variance Results of Cylindrical Body Sources

[0107]

[0108]

[0109] As can be seen from Table 2, the F value of the cylindrical body source is 0.13, which is less than F 0.05 and F 0.01 , indicating that there is no significant difference between the cylindrical body sources printed with the same placement method and between the cylindrical body sources printed with different placement methods, and further demonstrating the feasibility and accuracy of determining the activity of the thyroid body source 11 by the mass method.

[0110] In one embodiment, the thyroid body source 11 after value determination is assembled with the neck model 12 to form the neck-thyroid phantom 10, which specifically includes:

[0111] The thyroid body source 11 after value determination is wrapped by at least one of a heat shrinkable film or a food wrap.

[0112] The sealed thyroid body source 11 is placed in the accommodation cavity of the neck model 12.

[0113] Thus, it effectively prevents the leakage of radioactive substances caused by bumps, greatly reduces the risk of radioactive radiation exposure to operators, and also avoids the contamination of the laboratory environment and equipment by radioactive substances, ensuring the safety of the entire experimental process.

[0114] Specifically, using ordinary commercial photosensitive resin as the raw material, after printing the neck model 12 with a stereolithography 3D printer, the supporting convex points on the surface of the neck model 12 are polished, and the inside of the neck model 12 is hollowed out according to the shape of the thyroid gland source 11 to form a receiving cavity for installing the thyroid gland source 11. Subsequently, the thyroid gland source 11 wrapped with heat shrink film or plastic wrap is placed in the receiving cavity for efficiency calibration of the thyroid detector.

[0115] In a specific embodiment, a thyroid iodine detector is used to measure the neck-thyroid phantom 10, which specifically includes:

[0116] The neck-thyroid phantom 10 is attached to the surface of the detector probe for measurement.

[0117] The detection efficiency of the thyroid iodine detector for the neck-thyroid phantom 10 is obtained based on the net count rate and activity.

[0118] Specifically, the prepared thyroid gland source 11 has an activity of 5.1×10 4 Bq, with an uncertainty of 2.0%. The net count rate measured using the thyroid iodine detector is 6.16×10 2 s -1 , and the detection efficiency of the thyroid iodine detector for thyroid iodine can be obtained as 1.21%.

[0119] In one embodiment, tri-n-octylamine is used as the phase transfer agent, and isoamyl alcohol is used as the diluent of the phase transfer agent. They are prepared with a volume ratio of tri-n-octylamine to isoamyl alcohol of 1:1. The dosage of the phase transfer agent is added according to the mass ratio (phase transfer agent: photosensitive resin) = 1:30, and the addition amount of iodine element is added according to 500 mg / kg. At the same time, radioactive iodine-131 is added. 131 The activity concentration of

[0120] The phase transfer agent, 131 I and the photosensitive resin are stirred for 4 hours.

[0121] The light exposure parameters of the stereolithography 3D printer are set as: exposure light intensity 100%, exposure time 4.5 s.

[0122] The shape parameters of the thyroid gland were set, and a light-curing 3D printer was used for printing. Six Φ1cm×1cm cylindrical body sources were printed at the same time. The activity concentration was measured to be 49.5Bq / g. The mass of the thyroid body source 11 was 36.68g, and the activity was 1815.7Bq.

[0123] The thyroid body source 11 is protected by a plastic wrap and then assembled with the neck model 12, and can be used to calibrate the efficiency of the thyroid detector.

[0124] In one embodiment, 131 I is replaced by 152 Eu, for 152 Eu, to improve 152 The transfer efficiency of Eu is preferably selected as P204 as the phase transfer agent. The amount of the phase transfer agent is used according to the mass ratio (phase transfer agent: photosensitive resin) = 1:200 to 1:20. 152 The transfer efficiency of Eu is preferably (phase transfer agent: photosensitive resin) = 1:100 to 1:50.

[0125] 152 The amount of Eu added can be 100mg / kg to 500mg / kg. 152 The transfer efficiency of Eu is preferably 300 mg / kg to 450 mg / kg.

[0126] Phase transfer agent, 152 The mixing time of Eu and photosensitive resin is 2h to 24h. The mixing time can be freely selected according to the experimental schedule. Similarly, for other radionuclides, the available phase transfer agents can be investigated and the formula of the doped resin can be determined according to the above experimental method.

[0127] In one embodiment, a photo-curing 3D printer is used to print radioactive body sources of other human organs or other heterogeneous body sources, such as lungs, livers, plastic pipes, containers, etc., for efficiency calibration of the detector.

[0128] Another embodiment of the present application provides a neck-thyroid phantom 10, see Figure 2 and Figure 3 The neck-thyroid phantom 10 is prepared by any one of the preparation methods in the above embodiments. The neck-thyroid phantom 10 includes a thyroid body source 11 and a neck model 12.

[0129] The neck model 12 has a receiving cavity, and the thyroid body source 11 is located in the receiving cavity.

[0130] In this way, the diffusion state of radionuclides in human organs can be better simulated, making the detector efficiency calibration results more accurate and reliable.

[0131] In the description of the present application, the descriptions with reference to terms such as "in one embodiment", "in some embodiments", "in a specific embodiment", or "exemplary", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present application, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine the different embodiments or examples described in the present application and the features of the different embodiments or examples.

[0132] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are all included in the protection scope of the present application.

Claims

1. A method for preparing a neck-thyroid phantom, characterized in that: The preparation method comprises the following steps: Preparing a photosensitive resin containing a radioactive isotope; preparing a thyroid body source containing the photosensitive resin and a neck model matching the thyroid body source; Determining the activity of the thyroid source by mass method; The thyroid body source after setting is assembled with the neck model to form the neck-thyroid body phantom.

2. The preparation method according to claim 1, characterized in that: The photosensitive resin containing radioactive isotopes specifically comprises: The radioactive isotope is doped into the photosensitive resin by a phase transfer method.

3. The preparation method according to claim 2, characterized in that: The step of doping the radioactive isotope into the photosensitive resin by the phase transfer method specifically includes: The type and amount of the phase transfer agent, the amount of the radioisotope added and the mixing time are determined according to the radioisotope, and the phase transfer agent, the radioisotope and the photosensitive resin are mixed to form a photosensitive resin containing the radioisotope.

4. The preparation method according to claim 3, characterized in that: The phase transfer agent is an extractant for the radioisotope; The radioisotope is 131 I, the phase transfer agent comprises one of tri-n-octylamine extractant, dimethyl sulfoxide extractant and N,N-dimethylformamide extractant; or, The radioisotope is 152 Eu, the phase transfer agent includes one of a P507 extractant, a P204 extractant and a TBP extractant.

5. The preparation method according to claim 3, characterized in that: The mixing time is greater than or equal to 0.5 h and less than or equal to 24 h.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The preparation of the thyroid body source containing the photosensitive resin and the neck model matched therewith specifically comprises: Acquire anatomical data of the thyroid gland, generate a three-dimensional model of the thyroid gland using three-dimensional reconstruction technology, and design the neck model that matches the thyroid gland; Using the photosensitive resin containing the radioactive isotope as a raw material, and printing the thyroid source by using a photocurable 3D printer; The neck model is printed using a light-curing 3D printer using common commercial photosensitive resin as a raw material.

7. The preparation method according to claim 6, characterized in that: The adjustable range of the exposure light intensity of the light-curing 3D printer is greater than or equal to 60% and less than or equal to 100%; and / or, The exposure time of the light-curing 3D printer is greater than or equal to 3.5 s and less than or equal to 4.5 s.

8. The preparation method according to any one of claims 1 to 5, characterized in that: The method of determining the activity of the thyroid source by mass method specifically includes: Using the photosensitive resin containing the radioactive isotope as a raw material, a plurality of cylindrical body sources are printed by a light-curing 3D printer; The cylindrical source is calibrated by a high-purity germanium gamma spectrometer; Obtaining the unit mass source activity concentration of the cylindrical source; The activity of the thyroid body source is quantified according to the unit mass body source activity concentration.

9. The preparation method according to any one of claims 1 to 4, characterized in that: The step of assembling the thyroid body source after setting the value with the neck model to form the neck-thyroid body mold body comprises: The thyroid source after the setting value is wrapped with at least one of a heat shrink film or a plastic wrap; The sealed thyroid body source is placed in the accommodating cavity of the neck model.

10. A neck-thyroid phantom, characterized in that: The neck-thyroid phantom is prepared by the preparation method according to any one of claims 1 to 8, and the neck-thyroid phantom comprises: Thyroid origin; The neck model has a receiving cavity, and the thyroid gland source is located in the receiving cavity.

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