Combined inner core, phantom structure and perfusion method for nuclear medicine

Abstract

The present application relates to a combined inner core for nuclear medicine, comprising inner core assemblies, each of which is provided with at least one aperture of a hot spot hole; the inner core assemblies can be combined at will so that the combined inner core has at least six apertures of hot spot holes. A phantom structure is also provided, comprising a barrel body, the above-mentioned combined inner core and a barrel cover. An automatic bubble-free perfusion method for the phantom structure by means of an automatic perfusion device is also provided. The combined inner core of the present application is flexible to use, and can obtain the required resolution information in a single resolution evaluation. The cumbersome process of replacing the inner core and re-perfusion is avoided. The inner core assemblies of the present application are easy to process, saving production cost and time cost. The perfusion method enables the operator to minimize the risk of possible radiation hazards.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and in particular to a phantom device for nuclear medicine imaging technology. Background Technology

[0002] Early-stage cancer lesions are often small in size. Therefore, high spatial resolution SPECT (Single-Photon Emission Computed Tomography) or high spatial resolution PET (Positron Emission Tomography) are required to improve the early cancer detection rate and achieve the goal of early diagnosis of diseases, especially tumors.

[0003] In the past, many researchers have been working to improve the spatial resolution of SPECT and PET, and the development of commercial SPECT and PET has always regarded the improvement of spatial resolution as one of the key milestone parameters.

[0004] Figure 11 The Derenzo resolution phantom, currently the most widely used phantom, is shown. This phantom has a core diameter of approximately 200 mm and six different pore sizes on each core. During use, the pores are filled with a radioactive solution and placed inside the sealed phantom. Images are then acquired, and the resolution is determined based on these images. Because each core has only six pore groups, each test can only use these six fixed sizes. To test whether pores of other diameters can be resolved, the phantom core must be replaced, refilled, and the test repeated.

[0005] However, such cores are prone to air bubbles during the filling process, and refilling will inevitably expose operators to radiation damage again. In addition, a large number of cores need to be prepared at the same time, resulting in high time and economic costs. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the aforementioned problems in the prior art, this invention provides a combined core and phantom structure for nuclear medicine and its perfusion method. The combined core is flexible in use and can at least partially solve the aforementioned technical problems.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0010] The first aspect provides a modular inner core for nuclear medicine, the modular inner core comprising inner core assemblies, each inner core assembly being provided with at least one type of pore size for a hot vent.

[0011] The inner core assembly can be freely combined to give the combined inner core at least six different sizes of hot stove holes.

[0012] Preferably, the inner core assembly is fan-shaped, and the assembled combined inner core has a cylindrical structure;

[0013] Each core component that makes up the same composite core has the same radius;

[0014] The central angle Φ of the sector is greater than or equal to 60°.

[0015] Preferably, the central angle Φ of the sector is 60°, 120°, 180° or 240°.

[0016] Preferably, the inner core assembly has at least one through-hole area, and the hot stove hole is disposed in the at least one through-hole area;

[0017] The hot stove hole is a through hole that is arranged along the axial direction of the combined inner core and passes through the inner core assembly where the hot stove hole is located.

[0018] Within the same through-hole area, the diameter of the hot stove holes is the same, the distance between the centers of adjacent hot stove holes is twice the diameter of the hot stove hole, and the number of hot stove holes is greater than or equal to 3.

[0019] Preferably, the inner core assembly has a first sector-shaped surface and a second sector-shaped surface disposed opposite to each other, and the distance between the first sector-shaped surface and the second sector-shaped surface is the thickness H of the inner core assembly;

[0020] The smaller the diameter of the heating hole on the inner core assembly, the smaller the thickness of the inner core assembly.

[0021] Preferably, the ratio of the diameter D of the hot stove hole on the inner core assembly to the thickness H of the inner core assembly is D / H > 1 / 20.

[0022] Preferably, the inner core assembly further has an arcuate surface connecting the first sector surface and the second sector surface, and an arcuate groove is provided on the arcuate surface. When the inner core assembly is assembled into a combined inner core, the arcuate groove is connected so that the O-ring can be fitted onto the combined inner core.

[0023] The second aspect provides a phantom structure for nuclear medicine, the phantom structure comprising the combined inner core described in the first aspect, a barrel coaxially accommodating the combined inner core, and a barrel lid sealing the barrel;

[0024] The barrel body is a hollow cylindrical structure that is closed at one end and open at the other end.

[0025] The bucket lid is provided with at least one water injection hole for filling the bucket with water, and at least one vent hole for venting gas from the bucket.

[0026] Preferably, the barrel body includes: a barrel body, a bottom boss that closes the bottom of the barrel body, and a flange disposed on the top of the barrel body, wherein the bottom boss and the flange have the same maximum diameter;

[0027] The flange is provided with several threaded through holes at equal intervals to seal and connect with the bucket lid by means of fasteners.

[0028] The third aspect provides a method for pouring the aforementioned phantom structure, including:

[0029] Water is injected into the barrel of the mold structure using an automatic filling device until the barrel is full;

[0030] A radiopharmaceutical container containing a preset dose of radiopharmaceutical is connected in series to the liquid circulation pipeline of an automatic filling device, so that the automatic filling device, the barrel of the phantom structure, and the radiopharmaceutical container form a liquid circulation channel for mixing radiopharmaceutical, thereby obtaining a uniformly mixed liquid radioactive source.

[0031] (III) Beneficial Effects

[0032] The beneficial effects of this invention are:

[0033] First, the modular core for nuclear medicine provided by this invention is flexible in use. It allows for the selection and assembly of core components with appropriate hotspot apertures to form a modular core, enabling the acquisition of the required resolution information in a single resolution assessment. This avoids the cumbersome process of replacing and refilling the core in existing technologies where the hotspot aperture is fixed and different resolution information is needed. Furthermore, the core components of this invention are easy to manufacture, saving production and time costs.

[0034] Secondly, the mold structure provided by the present invention can achieve bubble-free automatic injection with the help of an automatic injection device.

[0035] Finally, by avoiding the need for core replacement and refilling, and by enabling bubble-free automatic refilling, operators can minimize the risk of potential radioactive hazards. Attached Figure Description

[0036] Figure 1 A schematic diagram of a combined inner core provided by the present invention;

[0037] Figure 2 A schematic diagram of the structure of an inner core component provided by the present invention;

[0038] Figure 3 for Figure 2 Top view of the inner core components;

[0039] Figure 4 A top view of another core assembly provided by the present invention;

[0040] Figure 5 This is a schematic diagram of another composite inner core provided by the present invention;

[0041] Figure 6 This is a partial schematic diagram of the phantom structure provided by the present invention;

[0042] Figure 7 A schematic diagram of the barrel lid structure of the mold structure provided by the present invention;

[0043] Figure 8 A schematic diagram of a hand-tightening sealing screw that can be used in the mold structure of this invention;

[0044] Figure 9 A schematic diagram of the self-locking connector used in the barrel body provided by this invention;

[0045] Figure 10 A cross-sectional schematic diagram of a mold structure equipped with a combined inner core provided by the present invention;

[0046] Figure 11 This is a schematic diagram of the core structure in the prior art.

[0047] [Explanation of Labels in the Attached Image]

[0048] 10: Modular inner core; 11: Inner core assembly; 12: Heating hole; 13: First sector-shaped surface; 14: Second sector-shaped surface; 15: Arc-shaped surface; 16: Arc-shaped groove;

[0049] 20: Barrel body; 21: Barrel frame; 22: Bottom boss; 23: Flange;

[0050] 30: Bucket lid; 31: Water inlet; 32: Vent. Detailed Implementation

[0051] To better explain and facilitate understanding of the present invention, it will be described in detail below with reference to the accompanying drawings and specific embodiments. However, these specific embodiments do not limit the scope of the present invention in any way.

[0052] Modular inner core

[0053] For SPECT and PET imaging systems, resolution evaluation is currently performed using phantoms. In these phantoms used for resolution evaluation, the core with multiple thermal foci is a crucial component. For example... Figure 11As shown, the Derenzo resolution phantom currently used most widely has six fixed hot spot apertures in its core. This means that for each core, only these six aperture sizes can be used for resolution evaluation at any given time. If the hot spot aperture required for a particular resolution evaluation is not on a core, the core must be replaced and the phantom refilled before the test can be conducted again.

[0054] Based on this, the present invention provides a composite inner core, such as... Figure 1-5 As shown, the combined inner core 10 includes an inner core assembly 11, and each inner core assembly 11 is provided with a hot stove hole 12 of at least one aperture.

[0055] The inner core assembly 11 can be freely combined so that the combined inner core 10 has at least 6 different sizes of hot stove holes.

[0056] In this way, during each resolution assessment, core components that meet the requirements are selected and assembled into a modular core, thereby completing the resolution assessment with the fewest possible perfusions and tests. This reduces both time costs and radiation exposure to operators.

[0057] It should be noted that, in the description of this invention, the aperture D of the hot stove hole refers to the diameter of the hole.

[0058] The combined inner core provided by the present invention will be described in detail below to help those skilled in the art to better understand it.

[0059] In this embodiment, the modular inner core 10 includes an inner core assembly 11, each inner core assembly 11 being provided with at least one type of heat cooker hole 12; the inner core assembly 12 can be arbitrarily combined as needed, so that the combined modular inner core 10 has six types of heat cooker holes.

[0060] like Figure 2-4 As shown, the inner core component 11 has a fan-shaped structure, and the combined inner core 10 formed by these components is a cylindrical structure. It is understood that all inner core components 11 that need to be assembled into a combined inner core 10 must have the same radius, which refers to the radius of the circle containing the fan-shaped component.

[0061] The inner core component 11 can be made of transparent acrylic (PMMA) material. Of course, other transparent materials, such as PC, PET, and ABS, can also be used as the manufacturing materials for the inner core component 11.

[0062] like Figure 2 , 3As shown, the central angle Φ of the inner core component 11 of the sector shape can generally be selected as 60°, which is beneficial for forming standardized components; however, it is acceptable that an angle greater than or equal to 60° is also acceptable, such as... Figure 4 As shown, the inner core component 11 has a central angle of 120°. Three of these inner core components 11 can be selected to complete the assembly of a combined inner core 10. Alternatively, inner core components 11 with different central angles can be combined to obtain a complete combined inner core 10 with a central angle of 360°. Therefore, the central angle Φ of the sector can be 60°, 120°, 180°, or 240°, etc.

[0063] The inner core assembly 11 has at least one through-hole area, such as Figure 2 , 3 The shown core assembly 11 has one through-hole area. Figure 4 The inner core assembly 11 shown has two through-hole areas, and the heating hole 12 is disposed in these through-hole areas; the larger the central angle of the inner core assembly 11, the more through-hole areas there are. For example, when the central angle of the inner core assembly 11 is 180°, the inner core assembly 11 has three through-hole areas.

[0064] The hot stove hole 12 is a through hole located in the through hole area. The through hole is arranged along the axial direction of the combined inner core and penetrates the hot stove hole 12, or in other words, the inner core assembly 11 where the through hole is located.

[0065] Within the same through-hole area, the diameter D of the hot stove holes 12 is the same; the diameter D of the hot stove holes 12 in different through-hole areas is different. The distance between the centers of adjacent hot stove holes 12 is twice the diameter of the hot stove hole, and the number of hot stove holes is greater than or equal to 3.

[0066] The inner core assembly 11 has a first sector-shaped surface 13 and a second sector-shaped surface 14 disposed opposite to each other, and the distance between the first sector-shaped surface 13 and the second sector-shaped surface 14 is the thickness H of the inner core assembly 11. Generally speaking, the smaller the diameter of the heating hole 12 on the inner core assembly 11, the smaller the thickness of the inner core assembly 11.

[0067] The above consideration is that, for this type of core structure used in nuclear medicine phantoms, when the diameter-to-depth ratio of the hot-pot holes on the core is less than 1 / 10, the processing is difficult, and it is not easy to guarantee the accuracy of the hot-pot holes. When the diameter-to-depth ratio is less than 1 / 20, ensuring the perpendicularity and dimensional tolerance of the holes is extremely difficult to process. Therefore, for the core assembly 11 with a fan-shaped structure provided in this embodiment, if the diameter of the hot-pot holes 12 is small, for example, 1.6mm, 1.2mm, or 1.0mm, the processing accuracy can be ensured by reducing the thickness H of the fan-shaped structure. The thickness of the fan-shaped structure can be reduced to 20mm or 16mm. This reduces the processing difficulty and cost, and also makes it easier to guarantee the processing accuracy of the hot-pot holes 12.

[0068] Furthermore, the inner core assembly 11 also has an arcuate surface 15 connecting the first sector surface 13 and the second sector surface 14. An arcuate groove 16 is provided on the arcuate surface. When the inner core assembly 11 is assembled into a combined inner core 10, the arcuate groove 16 is connected to form a complete circular groove, so that the O-ring can be fitted onto the combined inner core.

[0069] The inner core component 11 with the structure described above is small in size and can be processed to any size as needed, greatly increasing flexibility. Similarly, the modular inner core 10 with the structure described above can be combined with inner core components 11 with suitable hot stove hole 12 diameters according to actual needs, minimizing the number of tests required for the mold to obtain the required resolution evaluation, reducing the number of inner core replacements and refillings, reducing time and production costs, and reducing radiation damage to operators.

[0070] The present invention does not specifically limit the dimensions of the inner core component 11, as long as it has the above-described structure, it falls within the inventive concept of the present invention. The following is only an exemplary demonstration of the specific dimensions of the inner core component 11.

[0071] For the inner core assembly 11 with a central angle Φ of 60°, the sidewall structure connecting the first sector surface 13 and the second sector surface 14 is smooth and flat, with a flatness of less than 0.01 mm and a roughness of less than 3.2 μm. The inner core assembly 11 has a radius of 40 mm and a thickness H of 30 mm. The assembled composite inner core 10 has a through hole extending axially at its center, with a diameter of 4 mm. The function of this through hole is to fix the composite inner core 10 within the mold structure using threaded fasteners such as screws after it has been placed in the mold structure. The mold structure will be described in detail below.

[0072] The heating holes 12 are distributed within an isosceles triangular through-hole area formed at a distance of 4mm from the two straight sides of the sector. The first heating hole, which is the one closest to the center, is tangent to the two sides of the isosceles triangular through-hole area. The distance between the centers of adjacent heating holes 12 is twice the diameter of that heating hole 12. Thus, within the through-hole area, from the top view of the inner component 11, as shown... Figure 3 , 4 It can be clearly seen that the hot stove holes 12 are distributed in an equilateral triangle.

[0073] The arc-shaped groove 16 can be set at half the thickness H of the inner component 11, or it can be formed at both ends, that is, close to the first sector surface 13 and the second sector surface 14 respectively. The width of the arc-shaped groove 16 can be 2.5 mm and the depth can be 2.5 mm.

[0074] Furthermore, the diameter of the heating hole on the internal component 11, if it has only one through-hole area, such as... Figure 2 , 3 As shown, its aperture can be machined to 1.2mm, 1.6mm, 2.0mm, 2.4mm, 3.2mm, 4.0mm, 4.8mm, 6.4mm, or 7.9mm, etc. Due to the small size of this core assembly, it can be machined to any size as needed, greatly increasing flexibility.

[0075] The structure provided in this embodiment, which uses standardized and modular inner core components to form a combined inner core, is low in cost, flexible in configuration, and allows for the replacement of several sets of holes in the mold according to testing needs, greatly improving testing efficiency.

[0076] During resolution evaluation, based on system and testing needs, six core components 11, each with only one through-hole area, are selected and assembled. Then, O-rings made of elastic material are used, utilizing their elasticity to place them in the central arc-shaped groove 16, forming the core of the mold. Figure 1 The combined inner core 10 shown has heating holes with diameters of 2.4 mm, 3.2 mm, 4.0 mm, 4.8 mm, 6.4 mm, and 7.9 mm. (As shown...) Figure 5 Another type of combined inner core 10 is shown, with the diameters of its hot stove holes being 1.6 mm, 2.4 mm, 3.2 mm, 4.0 mm, 4.8 mm and 6.4 mm respectively.

[0077] phantom structure

[0078] like Figure 6-7As shown, the mold structure provided by the present invention includes the combined inner core 10, the barrel body 20, and the barrel lid 30 described above. The barrel body 20 is used to coaxially accommodate the combined inner core 10, and the barrel lid 30 is used to seal the barrel body 20. The barrel body 20 is a hollow cylindrical structure that is closed at one end and open at the other end. The barrel lid 30 is provided with at least one water injection hole 31 for injecting water into the barrel body 20, and at least one vent hole 32 for discharging gas from inside the barrel body 20.

[0079] In this embodiment, the barrel 20 includes: a barrel body 21, a bottom boss 22 that closes the bottom of the barrel body, and a flange 23 disposed on the top of the barrel body 21, i.e., the open end. The bottom boss 22 and the flange 23 have the same maximum diameter. The purpose is to enable the mold structure provided by this invention to be easily placed horizontally during use. After horizontal placement, the axis and bed surface of the barrel 20 remain in a horizontal position, which is more conducive to image acquisition. In this embodiment, the maximum diameter of the bottom boss 22 and the flange 23 is selected to be 100mm.

[0080] The flange 23 is provided with several threaded through holes at equal intervals to be sealed to the bucket lid 30 by means of fasteners.

[0081] The mold structure provided in this embodiment is made of transparent acrylic material. Of course, other transparent materials, such as PC, PET, and ABS, can also be used. The total height of the barrel 20 can be adjusted according to the height of the combined inner core 10 placed inside it as needed. In this embodiment, the total height of the barrel 20 can be 86mm, the outer diameter is 86mm, and the wall thickness is 3mm. The acrylic tubes processed into the barrel 20 have flat end faces, and the cylindrical surface does not need to be processed. This maintains the transparency of the acrylic surface while reducing workload and lowering costs.

[0082] The barrel body 21, bottom boss 22, and flange 23 are made of the same material. The bottom boss 22 is a stepped disc, with its maximum thickness (16mm in this embodiment) at the center of the disc, marking the third step. At this third step, a threaded blind hole is provided, allowing the aforementioned combined inner core 10 to be fixed to the barrel body 20 using fasteners. In this embodiment, the threaded blind hole is an M6 threaded hole with an effective thread depth of 10mm. The second step has a thickness of 10mm and a diameter of 80mm, which matches the inner diameter of the barrel body 21 in this embodiment. The first step, i.e., the maximum diameter of the bottom boss 22, has a thickness of 6mm.

[0083] The flange 23 located at the top of the barrel body 21 has a thickness of 8mm, an outer diameter of 100mm as described above, and an inner diameter of 86mm, which is the same as the outer diameter of the acrylic tube used to make the barrel body 21, so that the flange 23 can fit into the barrel body 21. Six or eight M5 threaded through holes are evenly spaced on the flange 23, and the center of the threaded through holes is located on a circumference with a diameter of 93mm.

[0084] The bottom boss 22 and flange 23 are bonded to both ends of the barrel body 21 using professional acrylic adhesive to ensure the strength and sealing after bonding.

[0085] In this embodiment, the bucket lid 30 has a diameter of 100mm and a thickness of 10mm. Figure 7 As shown, it is also made of acrylic. On the side facing the barrel body 21, corresponding to the flange 23, the barrel cover 30 is provided with an annular groove 24 for accommodating the O-ring to seal the barrel body 21. The groove has an inner diameter of 82mm, a width of 3.2mm, and a depth of 2.5mm. It also has 6 or 8 circular through holes at equal intervals, each with a diameter of 5.5mm.

[0086] The water inlet 31 on the lid 30 is equipped with a self-locking connector 33, such as... Figure 9 As shown, the self-locking connector 33 has a self-locking structure, enabling it to connect to a water pipe and thus allowing the mold structure to achieve air-free automatic filling using an automatic filling device. It is used in conjunction with a corresponding standard pipe connector during automatic filling. Of course, if manual filling is used, the water injection hole 31 can also be used with a hand-tightening plug, such as... Figure 8 As shown.

[0087] The above description of the dimensions of the combined inner core 10 and the barrel 20 is merely one design embodiment. The diameter and other dimensions of the combined inner core 10 and the barrel 20 can be expanded, as long as their inner and outer diameters can be used in combination. Currently, the inner core can be made with an outer diameter of 200mm, and the inner diameter of the barrel 20 can be slightly larger than 200mm.

[0088] Infusion method

[0089] Because manually pouring the phantom structure presents significant challenges in controlling bubble formation, it exposes operators to a radioactive environment, potentially causing harm. However, the phantom structure provided by this invention enables bubble-free pouring using existing automated pouring devices, while minimizing radiation exposure to operators.

[0090] The following is an exemplary description of the bubble-free automatic injection method for the phantom structure provided by the present invention, which specifically includes the following steps:

[0091] First, water is injected into the barrel of the mold structure using an automatic filling device until the barrel is full;

[0092] Secondly, a radiopharmaceutical container containing a preset dose of radiopharmaceutical is connected in series to the liquid circulation pipeline of an automatic filling device, so that the automatic filling device, the barrel of the phantom structure, and the radiopharmaceutical container form a liquid circulation channel for mixing radiopharmaceutical, thereby obtaining a uniformly mixed liquid radioactive source.

[0093] The automatic infusion device is prior art and can be achieved by any existing device capable of automatic infusion, such as the infusion system disclosed in the applicant's prior application CN202010074207.9, the contents of which are incorporated herein by reference.

[0094] Specifically, the automatic injection device includes components such as a power unit, a reversing valve, a gas washing bottle for discharging gas from the liquid circulation pipeline, a needle holder, and a radiopharmaceutical container.

[0095] At the beginning of the filling process, the required inner core components 11 are selected and assembled to obtain the corresponding modular inner core 10. This modular inner core 10 is then installed into the barrel 20, and M6x40 screws are used to fix the modular inner core 10 to the bottom boss 22 of the barrel 20. Figure 10 As shown.

[0096] Subsequently, the lid 30 is sealed to the flange 23 of the body 20. This sealing connection does not refer to a completely airtight connection, but rather to ensuring that the body 20 will not leak after subsequent liquid filling. Specifically, an M5x16 screw is used, threaded through a circular through-hole on the lid 30 and into a threaded through-hole on the flange 23, thus sealing the lid 30 to the body 20. During screw tightening, care must be taken to ensure smooth tightening so that the O-ring is evenly compressed by the screw tightening force, thereby guaranteeing that the body 20 will not leak during subsequent liquid filling.

[0097] After the filling begins, water is first injected into the barrel 20 through the power component, reversing valve and gas washing bottle of the automatic filling device with the help of an external water source, and then through the self-locking connector 224 connected to the water injection hole 31 of the barrel cover 30 until the barrel 20 is full.

[0098] Then, the radiopharmaceutical container containing a preset dose of radiopharmaceutical is connected in series to the liquid circulation pipeline of the automatic filling device through a needle seat that is pre-connected to the above-mentioned liquid circulation pipeline. The flow path into the gas washing bottle is changed by the reversing valve, so that the radiopharmaceutical in the radiopharmaceutical container enters the circulating liquid channel and is mixed evenly with the original water in the channel, and is injected into the barrel 20 to obtain a uniformly mixed liquid radioactive source.

[0099] Use with the corresponding standard pipe fittings during automatic filling.

[0100] Of course, the mold structure of this invention can also be manually poured. If manual pouring is used, the operator needs to unscrew the two hand-tightening sealing screws on the lid 30. The hand-tightening sealing screws are characterized by a groove at the bottom, with an O-ring seal inside the groove. Figure 8 As shown. Then, a certain concentration of FDG solution is injected using an injector. Due to the porous structure of the combined inner core 10 inside the barrel 20, which has multiple hot-sink holes, it is difficult to avoid the generation of air bubbles even with extreme care throughout the injection process. After the mold body 20 is filled, the operator needs to tighten the two hand-tightening sealing screws again. At this point, the injection is complete, and scanning imaging can be performed.

[0101] The phantom structure provided by this invention allows the use of a quick-connect pipe fitting with a self-locking mechanism to replace hand-tightening sealing screws. Water pipes can be inserted into this quick-connect pipe structure and self-lock, thereby enabling automatic filling and forming a high-quality, bubble-free phantom. After the phantom structure is filled, scanning and imaging can be performed, minimizing radioactive hazards to operators.

[0102] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite core for nuclear medicine, characterized in that: The combined inner core is the inner core of the Derenzo resolution phantom in a single-photon emission computed tomography system or a positron emission tomography system. The combined inner core includes an inner core assembly, and each inner core assembly is provided with a hot stove hole of at least one aperture. The inner core components can be freely combined to give the combined inner core at least six different aperture sizes for the hot stove holes. In each resolution evaluation, the inner core components that meet the requirements are selected and combined into a combined inner core as needed, thereby completing the resolution evaluation with the fewest number of injections and tests.

2. The combined inner core as described in claim 1, characterized in that: The inner core component is fan-shaped, and the assembled combined inner core has a cylindrical structure. Each core component that makes up the same composite core has the same radius; The central angle Φ of the sector is greater than or equal to 60°.

3. The combined inner core as described in claim 2, characterized in that: The central angle Φ of the sector is 60°, 120°, 180° or 240°.

4. The combined inner core as described in claim 2, characterized in that: The inner core assembly has at least one through-hole area, and the hot stove hole is disposed in the at least one through-hole area; The hot stove hole is a through hole that is arranged along the axial direction of the combined inner core and passes through the inner core assembly where the hot stove hole is located. Within the same through-hole area, the diameter of the hot stove holes is the same, the distance between the centers of adjacent hot stove holes is twice the diameter of the hot stove hole, and the number of hot stove holes is greater than or equal to 3.

5. The combined inner core as described in claim 2, characterized in that: The inner core assembly has a first sector-shaped surface and a second sector-shaped surface arranged opposite to each other, and the distance between the first sector-shaped surface and the second sector-shaped surface is the thickness H of the inner core assembly; The smaller the diameter of the heating hole on the inner core assembly, the smaller the thickness of the inner core assembly.

6. The combined inner core as described in claim 5, characterized in that: The ratio of the diameter D of the heating hole on the inner core assembly to the thickness H of the inner core assembly is D / H > 1 / 20.

7. The combined inner core as described in claim 5, characterized in that: The inner core assembly also has an arc-shaped surface connecting the first sector surface and the second sector surface. An arc-shaped groove is provided on the arc-shaped surface. When the inner core assembly is assembled into a combined inner core, the arc-shaped groove is connected so that an O-ring can be fitted onto the combined inner core.

8. A phantom structure for nuclear medicine, characterized in that: The mold structure includes the combined inner core as described in any one of claims 1-7, a barrel body coaxially accommodating the combined inner core, and a barrel lid that seals the barrel body; The barrel body is a hollow cylindrical structure that is closed at one end and open at the other end. The bucket lid is provided with at least one water injection hole for filling the bucket with water, and at least one vent hole for venting gas from the bucket.

9. The phantom structure as described in claim 8, characterized in that: The barrel body includes: a barrel body, a bottom boss that closes the bottom of the barrel body, and a flange provided on the top of the barrel body, wherein the bottom boss and the flange have the same maximum diameter; The flange is provided with several threaded through holes at equal intervals to be sealed to the bucket lid by means of fasteners.

10. A method for casting based on the phantom structure of claim 8 or 9, characterized in that, include: Water is injected into the barrel of the mold structure using an automatic filling device until the barrel is full; A radiopharmaceutical container containing a preset dose of radiopharmaceutical is connected in series to the liquid circulation pipeline of an automatic filling device, so that the automatic filling device, the barrel of the phantom structure, and the radiopharmaceutical container form a liquid circulation channel for mixing radiopharmaceutical, thereby obtaining a uniformly mixed liquid radioactive source.

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