Multi-point rodlike radioactive source suitable for solid model, and preparation method and application of multi-point rodlike radioactive source

Abstract

The invention provides a multi-point rodlike radioactive source suitable for a solid model and a preparation method and application of the multi-point rodlike radioactive source, and relates to the technical field of ionizing radiation protection standard radioactive source preparation. The rodlike radioactive source comprises a source carrier, a plurality of titration holes, a heat shrink tube and an outer tube; the manufacturing method of the rod-shaped radioactive source comprises the following steps: firstly, sealing a source carrier in a heat shrink tube in a heating manner, then sealing the source carrier sealed in the heat shrink tube in an outer tube, and sealing two ends of the outer tube. The multi-point rodlike radioactive source suitable for the solid model is prepared in a punching filling and multi-layer packaging mode, the leakage risk of the radioactive source can be reduced, the uniformity among point sources can be improved, the sealing safety and the use convenience of the radioactive source can be ensured, and compared with a point source or a line source manufactured through a traditional method, the multi-point rodlike radioactive source has the advantages that the manufacturing cost is reduced, and the manufacturing efficiency is improved. The method has the advantages of easy activity value setting and good uniformity.

Description

Technical Field

[0001] The present application relates to the technical field of preparation of standard radioactive sources for ionizing radiation protection, and in particular to a multi-point rod-shaped radioactive source suitable for a solid model, and a preparation method and application thereof. Background Art

[0002] In ionizing radiation protection work, it is usually necessary to make a solid physical model with uniform distribution of radioactive sources to simulate the uniform distribution of radioactive materials within a certain volume range in the human body or a specific sample. When simulating the uniform distribution of radioactive materials, the standard method is to fill a uniform radioactive solution in a container of a certain shape. The disadvantage of this method is that it is difficult to ensure the sealing integrity of the container. Once the container is damaged, it will cause leakage of the radioactive solution and diffusion of the radioactive material. Therefore, under the premise of meeting the error requirements, multi-line sources or multi-point sources are usually used to equivalently simulate the uniform distribution of radioactive solutions.

[0003] The production of line sources usually involves soaking a linear carrier (such as a thin rod or thin wire with good water absorption) in a radioactive solution of a certain concentration for a period of time, taking it out and drying it, and then packaging it to make the required line source. It is difficult to determine the total activity of radioactive substances in the line source produced by this method. It is difficult to ensure and prove the absorption of radioactive solutions by linear carriers of different materials and the uniformity of the deposition of radioactive substances on the carriers.

[0004] Point sources are usually made by dropping radioactive solution onto filter paper strips at a certain interval, inserting the filter paper strips into a thin plastic tube, and finally sealing the two ends of the plastic tube to obtain the desired point source. Although it is easy to determine the activity of the radioactive source obtained by this method, the filter paper is usually soft and difficult to insert smoothly into the thin plastic tube. Even if it can be inserted, it is easy to wrinkle, bend, or even pile up during later use, causing the relative position of the droplets to change, resulting in poor uniformity. Summary of the invention

[0005] In view of this, the present application provides a multi-point rod-shaped radioactive source suitable for solid models and a preparation method and application thereof, which solves the technical problems in the prior art that the total activity of radioactive materials is difficult to determine and the deposition uniformity of radioactive materials on the carrier is poor in the conventional rod-shaped radioactive source production.

[0006] As a first aspect of the present application, the present application provides a multi-point rod-shaped radiation source suitable for a solid model, comprising: a source carrier; a plurality of titration holes, the plurality of titration holes being evenly arranged on the source carrier, the plurality of titration holes being used to place a water-absorbing material; a heat shrinkable tube, the source carrier being encapsulated in the heat shrinkable tube; an outer tube, the heat shrinkable tube being encapsulated in the outer tube; wherein the material of the outer tube is the same as that of the source carrier, the lengths of the outer tube and the heat shrinkable tube are greater than the length of the source carrier, the heat shrinkable tube is used to encapsulate the source carrier in the heat shrinkable tube after being heated, and the outer tube is used to encapsulate the source carrier encapsulated in the heat shrinkable tube in the outer tube.

[0007] In one embodiment, the structure of the source carrier is a cylindrical structure; and / or the density of the source carrier is 0.9-1.4 g / cm 3 ; and / or, the material of the source carrier is one of polyethylene, nylon, and polystyrene; and / or, the diameter of the source carrier is 4 to 6 mm; and / or, the length of the source carrier is 85-90 mm.

[0008] In one embodiment, the diameter of the titration hole is between 3 and 5 mm; and / or the depth of the titration hole is between 3 and 5 mm.

[0009] In one embodiment, the heat shrink tube is any one of a PVC heat shrink tube, a PET heat shrink tube, and a heat shrink tube containing glue, and the wall thickness of the heat shrink tube is 0.5 to 1 mm.

[0010] In one embodiment, the density of the outer tube is 0.9-1.4 g / cm 3 The wall thickness of the outer tube is 0.5-1 mm, and the material of the outer tube is one of polyethylene, nylon, and polystyrene.

[0011] As a second aspect of the present application, the present application provides a method for preparing a rod-shaped radioactive source suitable for a solid model, comprising:

[0012] The source carrier is first cut into short sticks, a plurality of titration holes are drilled on the short sticks, a water-absorbing material is placed in the plurality of titration holes, and a radioactive standard solution is respectively dripped on the water-absorbing material in the titration holes to obtain a source carrier dripped with the radioactive standard solution;

[0013] The source carrier dripped with the radioactive standard solution is placed in a heat shrink tube and allowed to stand for 12-24 hours and then dried in the shade, and then placed in an oven for heating, the source carrier dripped with the radioactive standard solution is sealed in the heat shrink tube, and after the heat shrink tube is completely shrunk and tightly wrapped around the source carrier, the heat shrink tube is taken out of the oven, and after standing and cooling, the heat shrink tube that is completely shrunk and tightly wrapped around the source carrier is placed into an outer tube;

[0014] Sealant is injected into both ends of the outer tube for sealing, and the heat shrink tube is sealed to the outer tube. After the sealant at both ends of the outer tube solidifies, the sealant at both ends of the outer tube is repaired to obtain the above-mentioned multi-point rod-shaped radiation source suitable for solid models.

[0015] In one embodiment, the absorbent material is filter paper or cotton core, which is kneaded into a ball or cut into small pieces and inserted into the titration hole. The absorbent material is used to absorb the radioactive solution.

[0016] In one embodiment, the heating temperature of the heat shrinkable tube is 105° C.-115° C., and the heating time of the heat shrinkable tube is 10-20 minutes.

[0017] In one embodiment, the sealant is hot melt adhesive.

[0018] As the third aspect of the present application, the present application provides an application of a rod-shaped radioactive source suitable for a solid model, wherein the rod-shaped radioactive source described above or the rod-shaped radioactive source prepared by the preparation method described above is placed in a simulated solid model for calibrating the whole-body counter.

[0019] The present application provides a multi-point rod-shaped radioactive source suitable for a solid model, and a preparation method and application thereof. The rod-shaped radioactive source comprises a source carrier, a plurality of titration holes, a heat shrink tube, and an outer tube. The plurality of titration holes are arranged on the source carrier as a point source, the source carrier is first sealed in the heat shrink tube by heating, and then the source carrier sealed in the heat shrink tube is sealed in the outer tube, and both ends of the outer tube are sealed. The preparation method of the rod-shaped radioactive source is to titrate a plurality of point sources on a rod-shaped carrier, and the multi-point rod-shaped radioactive source suitable for a solid model is prepared by punching, filling, and multi-layer packaging. The multi-point rod-shaped radioactive source can reduce the risk of radioactive source leakage and improve the uniformity between each point source, and can ensure the sealing safety and convenience of use of the radioactive source. Compared with the point source or line source prepared by the traditional method, the multi-point rod-shaped radioactive source has the advantages of easy determination of activity and good uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a side view of a multi-point rod-shaped radiation source provided by an embodiment of the present application;

[0021] Figure 2 Shown is a top view of a multi-point rod-shaped radiation source provided by an embodiment of the present application;

[0022] Figure 3 Shown is a measurement energy spectrum diagram of a whole body counter provided in one embodiment of the present application.

[0023] Description of reference numerals:

[0024] 1. Outer tube; 2. Source carrier; 3. Titration hole; 4. Heat shrink tube; 5. Sealant. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically limited.

[0027] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In ionizing radiation protection work, it is usually necessary to make a solid physical model with uniform distribution of radioactive sources to simulate the uniform distribution of radioactive materials within a certain volume range in the human body or a specific sample. When simulating the uniform distribution of radioactive materials, multi-line sources or multi-point sources are usually used to equivalently simulate the uniform distribution of radioactive solutions.

[0029] The production of line sources usually involves soaking a linear carrier (such as a thin rod or thin wire with good water absorption) in a radioactive solution of a certain concentration for a period of time, taking it out and drying it, and then packaging it to make the required line source. It is difficult to determine the total activity of radioactive substances in the line source produced by this method. It is difficult to ensure and prove the absorption of radioactive solutions by linear carriers of different materials and the uniformity of the deposition of radioactive substances on the carriers.

[0030] Point sources are usually made by dropping radioactive solution onto filter paper strips at a certain interval, inserting the filter paper strips into a thin plastic tube, and finally sealing the two ends of the plastic tube to obtain the desired point source. Although it is easy to determine the activity of the radioactive source obtained by this method, the filter paper is usually soft and difficult to insert smoothly into the thin plastic tube. Even if it can be inserted, it is easy to wrinkle, bend, or even pile up during later use, causing the relative position of the droplets to change, resulting in poor uniformity.

[0031] It is difficult to determine the total activity of the radioactive material in the prepared line source. Although the prepared point source is easy to determine the activity of the radioactive source, it is easy to wrinkle and bend during later use, resulting in poor uniformity. The present application provides a multi-point rod-shaped radioactive source suitable for a solid model. Figure 1 is a side view of a multi-point rod-shaped radiation source provided in one embodiment of the present application, Figure 2 FIG. 1 is a top view of a multi-point rod-shaped radiation source provided in an embodiment of the present application. Figure 1 as well as Figure 2 As shown, the rod-shaped radiation source includes: a source carrier 2; a plurality of titration holes 3, which are evenly arranged on the source carrier 2, and in which water-absorbing materials are placed; a heat shrink tube 4, in which the source carrier 2 is placed; an outer tube 1, in which the heat shrink tube 4 is encapsulated; wherein the material of the outer tube 1 is the same as that of the source carrier 2, the lengths of the outer tube 1 and the heat shrink tube 4 are greater than the length of the source carrier 2, the heat shrink tube 4 is used to encapsulate the source carrier 2 in the heat shrink tube 4 after being heated, and the outer tube 1 is used to encapsulate the source carrier 2 encapsulated in the heat shrink tube 4 in the outer tube 1. By arranging a plurality of titration holes 3 as point sources on a source carrier 2, the source carrier 2 is first sealed in a heat shrink tube 4 by heating, and then the source carrier 2 sealed in the heat shrink tube 4 is sealed in an outer tube 1, and both ends of the outer tube 1 are sealed. By titrating a plurality of point sources on a rod-shaped source carrier and adopting a multi-layer packaging method, the risk of leakage of the radiation source can be reduced and the uniformity between the point sources can be improved, while the sealing safety and ease of use of the radiation source can be ensured.

[0032] As a preferred embodiment, the length of the outer tube 1 and the heat shrink tube 4 is greater than the length of the source carrier 2, which helps to seal the source carrier 2 in the heat shrink tube 4, and to seal the source carrier 2 sealed in the heat shrink tube 4 in the outer tube 1, thereby realizing multi-layer packaging of the source carrier 2 and ensuring the sealing performance of the radiation source.

[0033] As a preferred embodiment, the structure of the source carrier 2 is a columnar structure, which can be suitable for a solid model for simulating the uniform distribution of radioactive substances within a certain volume range in the human body or a specific sample.

[0034] Preferably, the density of the source carrier 2 is 0.9-1.4 g / cm 3The density of the source carrier 2 is selected to be consistent with the soft tissue of the human body or the density of the attenuation and shielding effect of ionizing radiation.

[0035] Preferably, the material of the source carrier 2 is one of polyethylene, nylon and polystyrene, and the material of the source carrier 2 is selected to be consistent with the soft tissue of the human body or a material having the same effect of attenuation or shielding of ionizing radiation.

[0036] Preferably, the diameter of the source carrier 2 is 4 to 6 mm; the diameter of the source carrier 2 of 4 to 6 mm is suitable for a solid model.

[0037] Preferably, the length of the source carrier 2 is 85-90 mm. The source carrier 2 of this length is suitable for a solid model, and is used to simulate the uniform distribution of radioactive substances within a certain volume range in the human body or a specific sample in ionizing radiation protection work.

[0038] As a preferred embodiment, the diameter of the titration hole 3 is 3 to 5 mm. The titration hole 3 can be used as a point source. A burette or a dispenser is used to drop the radioactive standard solution of Co-60 and other nuclides (such as Cs137 or Ba133) produced by Eckert&Ziegler onto the water-absorbing material in the titration hole 3.

[0039] Preferably, the depth of the titration hole 3 is 3 to 5 mm. The depth of 3 to 5 mm is convenient for placing a water-absorbing material in the titration hole 3 and for dripping the radioactive standard solution into the titration hole 3 .

[0040] As a preferred embodiment, the heat shrink tube 4 is any one of PVC heat shrink tube, PET heat shrink tube, and glue-containing heat shrink tube, and the wall thickness of the heat shrink tube 4 is 0.5-1 mm. The heat shrink tube is a special polyolefin heat shrink tube. The outer layer is made of high-quality soft cross-linked polyolefin material and the inner layer hot melt adhesive is composited. The outer layer material has the characteristics of insulation, corrosion resistance, and wear resistance. The inner layer has the advantages of low melting point, waterproof sealing, and high adhesion. The heat shrink tube 4 can be used to seal the source carrier 2 well in the heat shrink tube 4. The hot melt adhesive of the inner layer of the heat shrink tube 4 can well seal the source carrier 2 inside the heat shrink tube 4. At the same time, the cross-linked polyolefin material on the outside of the heat shrink tube 4 is insulated, corrosion-resistant, and wear-resistant.

[0041] As a preferred embodiment, the density of the outer tube 1 is 0.9 to 1.4 g / cm 3 The wall thickness of the outer tube 1 is 0.5-1 mm, and the material of the outer tube is one of polyethylene, nylon, and polystyrene. Similarly, the density and material of the outer tube 1 are selected to be consistent with the soft tissue of the human body or the material with the attenuation or shielding effect on ionizing radiation, so as to facilitate the simulation of the solid model.

[0042] As a second aspect of the present application, the present application provides a method for preparing a multi-point rod-shaped radioactive source suitable for a solid model, the preparation method comprising: first cutting a source carrier 2 into short rods, then drilling a plurality of titration holes 3 at equal intervals on the short rods, placing a water-absorbing material in the plurality of titration holes 3, and dripping a radioactive standard solution on the water-absorbing material in the titration holes 3, respectively, to obtain a source carrier 2 dripped with the radioactive standard solution;

[0043] The source carrier 2 dripped with the radioactive standard solution is placed in the heat shrink tube 4 and allowed to stand for 12-24 hours and then dried in the shade. The source carrier 2 dripped with the radioactive standard solution is then placed in an oven for heating. The source carrier 2 dripped with the radioactive standard solution is sealed in the heat shrink tube 4. After the heat shrink tube 4 is completely shrunk and tightly wrapped around the source carrier, the heat shrink tube 4 is taken out of the oven and allowed to stand for cooling. The heat shrink tube 4 that is completely shrunk and tightly wrapped around the source carrier 2 is then placed into the outer tube 1.

[0044] Sealant is injected into both ends of the outer tube 1 for sealing, and the heat shrink tube 4 is sealed to the outer tube 1. After the sealant at both ends of the outer tube 1 solidifies, the sealant at both ends of the outer tube 1 is repaired, and the above-mentioned rod-shaped radiation source is obtained after the repair.

[0045] This preparation method improves the uniformity between the point sources by titrating multiple point sources on a rod-shaped carrier, and adopts a punching, filling, and multi-layer packaging method, which can not only reduce the risk of radiation source leakage, but also ensure the sealing safety and ease of use of the radiation source.

[0046] As a preferred embodiment, the water-absorbing material is filter paper or cotton core, and the water-absorbing material is kneaded or cut into small sections and inserted into the titration hole 3. The water-absorbing material is used to absorb the radioactive solution. The existing point source is usually made by dripping the radioactive solution on the filter paper strip at a certain interval, and then inserting the filter paper strip into a thin plastic tube, and finally sealing the two ends of the plastic tube to obtain the desired point source. In this production method, since the filter paper is usually soft, it is difficult to insert it into the thin plastic tube smoothly. Even if it can be inserted, it is easy to wrinkle, bend, or even pile up during later use, so that the relative position between the droplets changes, resulting in poor uniformity. The present application forms the titration hole 3 by uniformly punching holes on the rod-shaped carrier, and fills the titration hole 3 with water-absorbing material to form a point source. Compared with the existing point source production method, it can ensure that the relative position between two adjacent point sources will not change, and the uniformity is good.

[0047] As a preferred embodiment, in step S4, the temperature of the oven is 105°C-115°C, and the time in the oven is 10-20 minutes. The source carrier 2 dripped with the radioactive standard solution is sealed in the heat shrink tube 4 by heating in the oven to avoid leakage of the radiation source and ensure the safety of the radiation source.

[0048] As a preferred embodiment, the sealant is hot melt adhesive. Filling the two ends of the outer tube 1 with hot melt adhesive can seal the outer tube 1 and further ensure the sealing safety of the radiation source.

[0049] As the third aspect of the present application, the present application also provides an application of a multi-point rod-shaped radioactive source suitable for a solid model, wherein the above-mentioned rod-shaped radioactive source or the rod-shaped radioactive source prepared by the above-mentioned preparation method is placed in a simulated solid model for calibrating the scale of a whole-body counter. Figure 3 The figure shows the measured energy spectrum of the whole body counter provided by one embodiment of the present application. The prepared multiple rod-shaped radioactive sources are placed in a simulated solid model, which is a model of a simulated human body. The simulated solid model of a simulated human body with multiple rod-shaped radioactive sources is then placed in a CANBERRA FASTSCAN type whole body counter for irradiation with X-rays or gamma rays. The whole body counter is a device that directly measures the X-rays or gamma rays emitted by radioactive substances taken into the body from outside the human body, thereby performing qualitative and quantitative analysis of radionuclides. The simulated solid model containing the rod-shaped radioactive sources is irradiated in the whole body counter to obtain the following: Figure 3 The measured energy spectrum of the whole body counter is shown in Figure 1. Figure 3 In the figure, the horizontal axis is the energy of gamma rays produced by the decay of radioactive nuclides, and the vertical axis is the counts of the corresponding energy. Figure 3 The middle peak is the area with more counts, indicating that the whole body counter has measured the nuclides of the rod-shaped radioactive source, thus proving the availability of the rod-shaped radioactive source.

[0050] As a preferred embodiment, the prepared rod-shaped radiation source is placed in a simulated solid model, and the simulated solid model is placed in a CANBERRA FASTSCAN whole-body counter for efficiency detection. In the whole-body counter measurement mode, the front end of the model is 15 cm away from the detector surface.

[0051] The standard method is adopted, that is, filling the container with the radioactive standard solution of Co-60 and other nuclides (such as Cs137 or Ba133) produced by Eckert&Ziegler Company, and then placing the container filled with the radioactive standard solution into the American Nuclear Technology BOMAB whole-body counter metrology model for effect comparison. As can be seen from Table 1, the deviation of the two models is only greater than 5% at low energy (59.5keV), and the deviation in the medium and high energy nuclide range usually monitored by the whole-body counter is less than 2%, which shows that the rod-shaped radiation source can replace the traditional standard model.

[0052] Table 1 Simulation table of detection efficiency of rod-shaped radioactive sources in different models

[0053]

[0054] Therefore, the present application selects a cylindrical tube made of polyethylene, nylon or polystyrene as the source carrier 2. The material is consistent with the attenuation and shielding effect of the soft tissue of the human body on ionizing radiation, which is convenient for simulating a solid model. A plurality of titration holes 3 are opened at equal intervals on the source carrier 2, and the titration holes 3 are used to fill the water-absorbing material. The radioactive standard solution is respectively dripped on the water-absorbing material in the plurality of titration holes 3 to form a fixed point source, and the source carrier 2 is sealed in the heat shrink tube 4 by heating to ensure the sealing safety of the radiation source. Then, the heat shrink tube 4 that seals the source carrier 2 is placed in the outer tube 1, and the two ends of the outer tube 1 are sealed for the second time with hot melt adhesive. The prepared rod-shaped radiation source can reduce the risk of radiation source leakage and improve the uniformity between the point sources, and can also ensure the sealing safety and ease of use of the radiation source. The prepared plurality of rod-shaped radiation sources are placed in a simulated solid model, and then the simulated solid model is placed in CANBERRA FASTSCAN type whole body counter, the whole body counter measured the radionuclides of the rod-shaped radioactive source, indicating that the rod-shaped radioactive source can be used to measure the radioactive source of the simulated solid model, and then the rod-shaped radioactive source is placed in the simulated solid model, the radioactive standard solution is filled in the container, and then it is placed in the American Nuclear Technology BOMAB whole body counter metrology model, and the effects of the two models (rod-shaped radioactive source and radioactive standard solution) are compared. The deviation of the two models is only greater than 5% at low energy (59.5keV), and the deviation in the medium and high energy nuclide range usually monitored by the whole body counter is less than 2%, indicating that the rod-shaped radioactive source can replace the traditional standard model. Compared with the point source or line source made by traditional methods, the multi-point rod-shaped radioactive source can not only reduce the risk of radioactive source leakage and improve the uniformity between each point source, but also ensure the sealing safety and ease of use of the radioactive source.

[0055] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-point rod-shaped radiation source suitable for a solid model, characterized in that: include: Source carrier (2); A plurality of titration holes (3), wherein the plurality of titration holes (3) are evenly arranged on the source carrier (2), and the plurality of titration holes (3) are used to place water-absorbing materials; A heat shrink tube (4), wherein the source carrier (2) is encapsulated in the heat shrink tube (4); An outer tube (1), wherein the heat shrink tube (4) is encapsulated in the outer tube (1); The material of the outer tube (1) is the same as that of the source carrier (2), and the lengths of the outer tube (1) and the heat shrink tube (4) are greater than the length of the source carrier (2).

2. The multi-point rod-shaped radiation source according to claim 1, characterized in that: The structure of the source carrier (2) is a columnar structure; And / or, the density of the source carrier is 0.9-1.4 g / cm 3 ; And / or, the source carrier (2) is made of one of polyethylene, nylon and polystyrene; and / or, the source carrier (2) has a diameter of 4 to 6 mm; And / or, the length of the source carrier (2) is 85-90 mm.

3. The multi-point rod-shaped radiation source according to claim 1, characterized in that: The diameter of the titration hole (3) is between 3 and 5 mm; and / or the depth of the titration hole (3) is between 3 and 5 mm.

4. The multi-point rod-shaped radiation source according to claim 1, characterized in that: The heat shrink tube (4) is one of a PVC heat shrink tube, a PET heat shrink tube, and a heat shrink tube containing glue; the wall thickness of the heat shrink tube (4) is 0.5-1 mm.

5. The multi-point rod-shaped radiation source according to claim 1, characterized in that: The density of the outer tube (1) is 0.9-1.4 g / cm 3 The wall thickness of the outer tube (1) is 0.5-1 mm, and the material of the outer tube (1) is one of polyethylene, nylon, and polystyrene.

6. A method for preparing a multi-point rod-shaped radioactive source suitable for a solid model according to any one of claims 1 to 5, characterized in that: include: The source carrier (2) is cut into short rods, a plurality of titration holes (3) are drilled on the short rods, a water-absorbing material is placed in the plurality of titration holes (3), and a radioactive standard solution is dripped onto the water-absorbing material in the titration holes (3) to obtain a source carrier (2) dripped with the radioactive standard solution; The source carrier (2) dripped with the radioactive standard solution is placed in a heat shrink tube (4) and left to stand for 12-24 hours and then dried in the shade. The source carrier (2) dripped with the radioactive standard solution is then placed in an oven for heating. The source carrier (2) dripped with the radioactive standard solution is sealed in the heat shrink tube (4). After the heat shrink tube (4) is completely shrunk and tightly wrapped around the source carrier (2), the heat shrink tube (4) is taken out of the oven. After being left to stand and cooled, the heat shrink tube (4) that is completely shrunk and tightly wrapped around the source carrier (2) is placed in the outer tube (1); Sealant is injected into both ends of the outer tube (1) for sealing, the heat shrink tube (4) is sealed to the outer tube (1), and after the sealant at both ends of the outer tube (1) solidifies, the sealant at both ends of the outer tube (1) is repaired, and after the repair, a multi-point rod-shaped radiation source suitable for a solid model is obtained.

7. The preparation method according to claim 6, characterized in that: The water-absorbing material is filter paper or cotton core. The water-absorbing material is kneaded into a ball or cut into small pieces and inserted into the titration hole (3). The water-absorbing material is used to absorb the radioactive solution.

8. The preparation method according to claim 6, characterized in that: The heating temperature of the heat shrinkable tube (4) is 105° C.-115° C., and the heating time of the heat shrinkable tube (4) is 10-20 minutes.

9. The preparation method according to claim 6, characterized in that: The sealant is hot melt adhesive.

10. An application of a multi-point rod-shaped radiation source suitable for a solid model, characterized in that: The multi-point rod-shaped radioactive source described in any one of claims 1 to 5 or the multi-point rod-shaped radioactive source prepared by the preparation method described in any one of claims 6 to 9 is placed in a simulated solid model for calibrating the whole body counter.

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