Method for manufacturing a collimator, collimator, and tomographic imaging system

Abstract

The present invention provides a collimator manufacturing method, a collimator and a tomographic imaging system. The collimator manufacturing method includes: using computer 3D modeling to model the 3D model of the collimator, the 3D model including a cylindrical body, and the cylindrical body having a plurality of pinholes penetrating the side wall in the radial direction; according to the 3D model, using selective laser sintering to sinter and form the collimator. As described above, through 3D modeling and selective laser sintering, a collimator with a plurality of pinholes can be integrally sintered and formed. Compared with the prior art, the present invention can greatly reduce the assembly error, thereby greatly reducing the deviation between the actual position and the designed position of the pinholes on the formed collimator, enabling the actual spatial resolution of the tomographic imaging system to meet the designed resolution, which is beneficial to ensuring the quality of tomographic imaging.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly relates to a method for manufacturing a collimator, a collimator, and a tomographic imaging system. Background Art

[0002] Multi-pinhole collimators have been widely used in clinical and pre-clinical single photon emission computed tomography (SPECT) systems. For relatively small scanning objects such as small animals, human brains, hearts, thyroids, and mammary glands, multi-pinhole collimators are the main means to simultaneously achieve high-sensitivity and high-resolution SPECT imaging.

[0003] Traditional multi-pinhole collimators are mostly produced by machining methods. However, machining methods often result in relatively large dimensional errors of the machined pinholes, and the current pinhole design and arrangement methods on multi-pinhole collimators are becoming more and more complex. If machining methods are still used for processing, the processing difficulty is relatively large.

[0004] Although some manufacturers have considered using metal 3D printing technology to process multi-pinhole collimators, due to technical limitations, the multi-pinhole collimator is usually printed and formed in multiple parts separately, and then the formed parts are assembled to form the final multi-pinhole collimator. In this way, a relatively large assembly error will inevitably be introduced, resulting in a large deviation between the actual position of the pinhole and the designed position, which will cause a difference between the actual spatial resolution of the SPECT system and the designed resolution, thus affecting the quality of tomographic imaging. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for manufacturing a collimator, a collimator, and a tomographic imaging system to solve the problem that the processing method of the multi-pinhole collimator will introduce a relatively large assembly error and affect the quality of tomographic imaging.

[0006] To solve the above technical problems, based on the first aspect of the present invention, the present invention provides a method for manufacturing a collimator, which includes:

[0007] Using a computer to 3D model a 3D model of the collimator, the 3D model includes a cylindrical body, and the cylindrical body has a plurality of pinholes penetrating the side wall in the radial direction;

[0008] According to the 3D model, using selective laser sintering to sinter and form the collimator.

[0009] Optionally, the sintering material used in the selective laser sintering method is metal.

[0010] Optionally, the pinhole includes a first flared section and a second flared section. The first flared section and the second flared section are sequentially connected outward along the radial direction of the cylindrical body, and the radial dimension of the first flared section gradually decreases outward along the radial direction of the cylindrical body, while the radial dimension of the second flared section gradually increases outward along the radial direction of the cylindrical body.

[0011] Optionally, at least one of the cross-sections of the first flared section and the cross-section of the second flared section is circular, elliptical or polygonal.

[0012] Optionally, the 3D model further includes a plurality of extension bodies corresponding to the pinholes one by one. The extension bodies protrude outward from the cylindrical body on the outer wall of the cylindrical body, and the extension bodies and the corresponding pinholes are arranged in alignment along the radial direction of the cylindrical body. The pinholes also extend through the corresponding extension bodies.

[0013] Optionally, the cylindrical body includes multiple cylindrical layers which are concentrically arranged and sequentially spaced apart along the radial direction of the cylindrical body; the pinholes sequentially penetrate through the multiple cylindrical layers.

[0014] Optionally, the cylindrical body includes at least one end ring, and the end ring is provided on at least one side of the cylindrical body along the axial direction. The end ring is used to connect the multiple cylindrical layers.

[0015] Optionally, a plurality of the pinholes are arranged in a circumferential arrangement around the cylindrical body to form a pinhole ring assembly, and the 3D model includes a plurality of the pinhole ring assemblies which are spaced apart along the axial direction of the cylindrical body.

[0016] Based on the second aspect of the present invention, the present invention further provides a collimator, which includes a cylindrical body, and the cylindrical body includes one or more cylindrical layers; a plurality of pinholes are provided on at least one of the cylindrical layers, and the plurality of pinholes are obtained by means of 3D printing and integral molding.

[0017] Based on the third aspect of the present invention, the present invention further provides a tomography system, which includes:

[0018] A collimator, which includes a cylindrical body, and the cylindrical body includes one or more cylindrical layers; a plurality of pinholes are provided on at least one of the cylindrical layers, and the plurality of pinholes are obtained by means of 3D printing and integral molding;

[0019] A detection cylinder which surrounds the collimator; wherein, the detection cylinder includes a plurality of detectors, and the detectors are arranged in alignment with the pinholes along the radial direction of the collimator.

[0020] In summary, in the collimator manufacturing method, collimator, and tomographic imaging system provided by the present invention, the collimator manufacturing method includes: using computer 3D modeling to model the 3D model of the collimator, the 3D model including a cylindrical body, and the cylindrical body having a plurality of pinholes penetrating the side wall in the radial direction; according to the 3D model, using selective laser sintering to sinter and form the collimator. As above, through 3D modeling and selective laser sintering, a collimator with a plurality of pinholes can be integrally sintered and formed. Compared with the prior art, the present invention can greatly reduce the assembly error, thereby greatly reducing the deviation between the actual position and the designed position of the pinholes on the formed collimator, enabling the actual spatial resolution of the tomographic imaging system to meet the designed resolution, which is beneficial to ensuring the quality of tomographic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Those of ordinary skill in the art should understand that the provided drawings are used to better understand the present invention and do not constitute any limitation to the scope of the present invention. Among them:

[0022] Figure 1A is a schematic diagram of the cooperation between the collimator and the detector;

[0023] Figure 1B is another schematic diagram of the cooperation between the collimator and the detector;

[0024] Figure 2 is a schematic diagram of the collimator manufacturing method according to an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of the 3D model of the collimator according to an embodiment of the present invention;

[0026] Figure 4 is another schematic diagram of the 3D model of the collimator according to an embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of the pinhole according to an embodiment of the present invention;

[0028] Figure 6 is another schematic diagram of the pinhole according to an embodiment of the present invention.

[0029] In the drawings:

[0030] P - collimator; Q - detection cylinder; FOV - scanning area; E - pinhole;

[0031] 10 - cylindrical body; 100 - pinhole; 101 - first flared section; 102 - second flared section; 110 - cylindrical layer; 20 - extension body. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the objectives, advantages and features of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are all in very simplified forms and are not drawn to scale, and are only used to facilitate and clearly assist in explaining the objectives of the embodiments of the present invention. In addition, the structures shown in the accompanying drawings are often part of the actual structures. In particular, the focus to be shown in each of the accompanying drawings is different, and sometimes different scales are used.

[0033] As used in the present invention, the singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in the sense of including "and / or", the term "several" is generally used in the sense of including "at least one", the term "at least two" is generally used in the sense of including "two or more", in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or at least two of such features, "one end" and "the other end" and "proximal end" and "distal end" generally refer to two corresponding parts, which not only include the endpoints, the terms "mounted", "connected", "coupled" shall be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, it may be the communication inside two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element being disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the two elements may be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element may be inside, outside, above, below or on one side of another element, etc. in any orientation, unless otherwise explicitly stated in the content. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Figure 1A is a schematic diagram of the cooperation between the collimator and the detector, Figure 1BIt is another schematic diagram of the collimator cooperating with the detector. The collimator P is in the shape of an annular cylinder (usually a polygonal ring, and of course it can also be a circular ring). The collimator P is evenly provided with a plurality of pinholes E along the circumferential direction. The overlapping part of the radiation ranges of the plurality of pinholes E is called the scanning area FOV. The scanning area FOV is usually polygonal (preferably a regular polygon), and can also be circular. A plurality of detectors are arranged around the collimator to form a detection cylinder Q, and the detection cylinder Q and the collimator P are concentrically arranged, and the detectors are aligned with the pinholes E. During specific operation, based on the imaging principle of SPECT, the object to be examined (the object to be examined can be a small animal or a human body) first ingests a radioactive isotope drug with an appropriate half-life, and the patient is placed within the scanning area FOV of the collimator P. After the drug reaches the tomographic position to be imaged, due to radioactive decay, γ photons will be emitted from the tomographic position. The detectors will receive the γ photons passing through the pinholes and coming in along the same projection line (i.e., forming high-energy γ rays). The detectors convert the received high-energy γ rays into light signals with lower energy but larger quantity through a scintillator, and convert the light signals into electrical signals and amplify them through a photoelectric sensor. The obtained measurement value represents the sum of the radioactivity of the object to be examined on this projection line, so as to obtain tomographic image data of the object to be examined.

[0035] The spatial resolution of the SPECT system is largely related to the following formula:

[0036]

[0037] Among them,

[0038] R represents the spatial resolution of the SPECT system;

[0039] M is the magnification of the SPECT system, M = l2 / l1, l1 represents the distance from the pinhole to the detector, and l2 represents the distance from the pinhole to the center of the scanning area;

[0040] R i represents the resolution of the detector;

[0041] D represents the diameter size of the pinhole.

[0042] Combined with the above formula and referring to Figure 1 and Figure 2 it can be seen that when the inner diameter of the annular detection cylinder Q is determined (i.e., the sum of l1 and l2 remains unchanged), and the diameter D of the pinhole is determined, the larger l1 is, the smaller l2 is, the smaller M is, and the larger R is.

[0043] Furthermore, when the collimator is manufactured by machining, there will inevitably be machining errors in l2 and D, resulting in a large deviation between the spatial resolution of the SPECT system and the designed resolution. If the collimator is divided into multiple parts and printed and formed separately, and then the formed parts are assembled to form the final multi-pinhole collimator, a large assembly error will also be introduced, resulting in a large deviation between the actual position of the pinholes and the designed position, thus causing a large deviation between l2 and D and the designed values, and ultimately resulting in a large deviation between the spatial resolution of the SPECT system and the designed resolution, which will further affect a series of indicators such as the sensitivity of the SPECT system, the uniformity of the image, and the image quality.

[0044] In view of this, an embodiment of the present invention provides a collimator manufacturing method, a collimator, and a tomographic imaging system to solve the problem that the machining method of the multi-pinhole collimator will introduce a large assembly error and affect the quality of tomographic imaging.

[0045] Figure 2 It is a schematic diagram of the collimator manufacturing method according to an embodiment of the present invention. Figure 3 It is a schematic diagram of the 3D model of the collimator according to an embodiment of the present invention. As Figure 2 shown, an embodiment of the present invention provides a collimator manufacturing method, and the method includes:

[0046] Step S1: Use computer 3D modeling to model the 3D model of the collimator. Refer to Figure 3 , the 3D model includes a cylindrical body 10, and the cylindrical body 10 has a plurality of pinholes 100, and the pinholes 100 penetrate the side wall of the cylindrical body 10 along the radial direction of the cylindrical body 10. It should be noted that the cross-sectional shape of the cylindrical body 10 can be circular or polygonal (such as a regular octagon), and the present invention does not limit this.

[0047] Step S2: According to the 3D model, the collimator is sintered into shape by selective laser sintering. Understandably, selective laser sintering (SLS) usually operates in an inert gas processing chamber filled with helium. In this embodiment, specifically, a very thin layer of fusible powder is first deposited on the bottom plate of the forming barrel, and the bottom plate can move vertically up and down within the forming barrel. Then the computer controls the movement trajectory of the CO2 laser beam according to the data of the 3D model, scans and melts the fusible powder, and adjusts the laser beam intensity to sinter and solidify the powder within a preset layer height range (such as a range of 0.05 mm - 0.25 mm). In this way, when the laser beam scans and moves along a given path, the powder in the area passed through can be sintered, thereby generating one cross-section after another of the prototype of the collimator. Each layer of SLS sintering is carried out on top of the previous layer, so that the currently sintered layer can be firmly bonded to the previous layer. After the prototype of the collimator is sintered, the unsintered powder can be removed with a brush or compressed air.

[0048] For the above collimator manufacturing method, through 3D modeling and selective laser sintering, the collimator with multiple pinholes 100 can be integrally sintered into shape. Compared with the prior art, the present invention can greatly reduce the assembly error, thereby greatly reducing the deviation between the actual position and the designed position of the pinholes 100 on the formed collimator, so that l2 and D have almost no deviation from the designed values, and the spatial resolution of the SPECT system meets the designed resolution, which is beneficial to ensuring the quality of tomographic imaging.

[0049] The materials of the soluble powder used in SLS usually include nylon, wax, ABS, resin-coated sand (coated sand), polycarbonates, metals, and ceramics. In this embodiment, the sintering material used in the selective laser sintering method is a metal, such as tungsten.

[0050] Figure 4 It is another schematic diagram of the 3D model of the collimator according to an embodiment of the present invention. In a preferred embodiment, please refer to Figure 4 , the cylindrical body 10 includes multiple layers of cylindrical layers 110, the radial dimensions of each layer of cylindrical layer 110 are different, the multiple layers of cylindrical layers 110 are concentrically arranged, and are arranged at intervals (preferably at equal intervals) along the radial direction of the cylindrical body 10; the pinholes 100 sequentially penetrate through the multiple layers of cylindrical layers 110. In this way, when performing 3D modeling, the cylindrical body 10 is divided into multiple layers of cylindrical layers 110 arranged at intervals along the radial direction, which can save the sintering material (i.e., metal powder) during the SLS process, save costs, and reduce the weight of the formed collimator.

[0051] Further, the tubular body 10 includes at least one end ring (not shown), the end ring is provided on at least one side of the tubular body 10 along the axial direction, and the end ring is used to connect the tubular layers 110. Preferably, end rings are provided on both sides of the tubular body 10 along the axial direction to increase the connection stability between the tubular layers 110.

[0052] Figure 5 is a schematic diagram of the pinhole 100 according to an embodiment of the present invention, Figure 6 is another schematic diagram of the pinhole 100 according to an embodiment of the present invention. Refer to Figure 5 and Figure 6 , the pinhole 100 includes a first flared section 101 and a second flared section 102, the first flared section 101 and the second flared section 102 are sequentially connected outward along the radial direction of the tubular body 10, and the radial dimension of the first flared section 101 gradually decreases outward along the radial direction of the tubular body 10, and the radial dimension of the second flared section 102 gradually increases outward along the radial direction of the tubular body 10. It can be understood that this radial dimension refers to the maximum dimension of the pinhole 100 along the radial direction. When the cross-section of the pinhole 100 is circular, it refers to the diameter.

[0053] Further, at least one of the cross-section of the first flared section 101 and the cross-section of the second flared section 102 is circular, elliptical or polygonal. It should be understood that the cross-section here refers to the cross-section of the pinhole 100 along its own radial direction. By way of example, the first flared section 101 and the second flared section 102 include, but are not limited to, combinations of frustum shapes and frustum shapes, combinations of frustum shapes and elliptical frustum shapes, or combinations of frustum shapes and prism shapes.

[0054] Preferably, the cross-section of the distal end of the first flared section 101 (the end of the first flared section 101 away from the center of the tubular body 10) is the same as the cross-section of the proximal end of the second flared section 102 (the end of the second flared section 102 close to the center of the tubular body 10), and the radial dimension of the distal end of the first flared section 101 is the same as the radial dimension of the proximal end of the second flared section 102, so that the first flared section 101 and the second flared section 102 are matched and connected. For example, both the distal end of the first flared section 101 and the proximal end of the second flared section 102 are circular and have the same diameter.

[0055] Preferably, the 3D model further includes a plurality of extension bodies 20 corresponding to the pinholes 100 one by one. The extension bodies 20 protrude radially outward from the cylindrical body 10 on the outer wall of the cylindrical body 10, and the extension bodies 20 and the corresponding pinholes 100 are arranged in alignment along the radial direction of the cylindrical body 10. The pinholes 100 also extend through the corresponding extension bodies 20. With such an arrangement, the pinholes 100 can be made to protrude, protruding outward from the cylindrical body 10. After the collimator is sintered and formed, it is beneficial for the external detector to detect and receive γ-rays of higher quality, ensuring the quality of the ray projection shape, and thus obtaining a better-quality imaging image.

[0056] Generally, the plurality of pinholes 100 are arranged regularly in a predetermined manner, otherwise it will affect the quality of tomographic imaging. In one embodiment, the plurality of pinholes 100 are arranged in a circumferential arrangement around the cylindrical body 10 to form a pinhole ring assembly. The pinhole ring assembly is annular, and the plurality of pinholes 100 in the pinhole ring assembly are preferably arranged at equal intervals. Further, the 3D model includes a plurality of the pinhole ring assemblies arranged at intervals (uniformly) along the axial direction of the cylindrical body 10.

[0057] This embodiment also provides a collimator, which includes a cylindrical body 10. The cylindrical body 10 includes one or more cylindrical layers 110. A plurality of pinholes 100 are provided on at least one of the cylindrical layers 110, and the plurality of pinholes 100 are obtained by 3D printing and integrally formed, that is, the cylindrical body 10 and the plurality of provided pinholes 100 are integrally formed by 3D modeling and selective laser sintering method. It should be noted that the collimator is sintered and formed according to the described 3D model. For the specific structural shape of the collimator, reference can be made to the description of the structural shape of the 3D model, and details will not be elaborated here.

[0058] This embodiment also provides a tomographic imaging system. The tomographic imaging system of this embodiment is, for example, a single photon emission computed tomography (SPECT) system. Further, the tomographic imaging system includes a collimator and a detection cylinder. The collimator includes a cylindrical body 10. The cylindrical body 10 includes one or more cylindrical layers 110. A plurality of pinholes 100 are provided on at least one of the cylindrical layers 110, and the plurality of pinholes 100 are obtained by 3D printing and integrally formed. The detection cylinder is arranged around the collimator, preferably arranged concentrically with the collimator. Among them, the detection cylinder includes a plurality of detectors, and the detectors and the pinholes are arranged in alignment along the radial direction of the collimator (cylindrical body). Preferably, the tomographic imaging system includes a plurality of detectors corresponding to the pinholes 100 of the collimator one by one, and the detectors and the corresponding pinholes 100 are arranged in alignment along the radial direction of the collimator.

[0059] In addition, in order to save costs, other structures in the tomographic imaging system can be formed by machining instead of 3D printing. For example, the structural members for fixing the collimator to the gantry of the tomographic imaging system can be formed by machining.

[0060] It should be noted that since the tomographic imaging system includes the collimator described above, the tomographic imaging system also has the beneficial effects brought by the collimator. For the working principle of tomographic imaging and other devices, those skilled in the art can learn from the prior art. For example, the tomographic imaging system of this embodiment further includes an image reconstruction device and a computer. The image reconstructor is respectively connected to the detector and the computer and is used to obtain tomographic scan images.

[0061] In summary, in the collimator manufacturing method, collimator and tomographic imaging system provided by the present invention, the collimator manufacturing method includes: using computer 3D modeling to create a 3D model of the collimator, the 3D model includes a cylindrical body, and the cylindrical body has a plurality of pinholes penetrating the side wall in the radial direction; according to the 3D model, using selective laser sintering to sinter the collimator into shape. As described above, through 3D modeling and selective laser sintering, a collimator with a plurality of pinholes can be integrally sintered into shape. Compared with the prior art, the present invention can greatly reduce the assembly error, thereby greatly reducing the deviation between the actual position and the designed position of the pinholes on the formed collimator, enabling the actual spatial resolution of the tomographic imaging system to meet the designed resolution and facilitating the guarantee of the quality of tomographic imaging.

[0062] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure belong to the protection scope of the technical solution of the present invention.

Claims

1. A method for manufacturing a collimator, the collimator being applicable to an SPECT system, characterized in that, Comprising: Using computer 3D modeling to model the 3D model of the collimator, the 3D model includes a cylindrical body, and the cylindrical body has a plurality of pinholes penetrating the side wall in the radial direction; the cylindrical body includes multiple cylindrical layers, the multiple cylindrical layers are concentrically arranged, and are sequentially spaced apart in the radial direction of the cylindrical body; the pinholes sequentially penetrate through the multiple cylindrical layers; According to the 3D model, using selective laser sintering to sinter and form the collimator; Wherein, the cylindrical body and the plurality of pinholes are integrally formed by 3D modeling and selective laser sintering; The sintering material used in the selective laser sintering method is metal; The pinhole includes a first flared section and a second flared section, the first flared section and the second flared section are sequentially connected outward in the radial direction of the cylindrical body, and the radial dimension of the first flared section gradually decreases outward in the radial direction of the cylindrical body, and the radial dimension of the second flared section gradually increases outward in the radial direction of the cylindrical body.

2. The method for manufacturing a collimator according to claim 1, wherein At least one of the cross-section of the first flared section and the cross-section of the second flared section is circular, elliptical or polygonal.

3. The method for manufacturing a collimator according to claim 1, wherein The 3D model further includes a plurality of extensions corresponding to the pinholes one by one, the extensions protrude from the outer wall of the cylindrical body radially outward from the cylindrical body, and the extensions and the corresponding pinholes are arranged in alignment in the radial direction of the cylindrical body, and the pinholes also extend through the corresponding extensions.

4. The method for manufacturing a collimator according to claim 1, wherein The cylindrical body includes at least one end ring, at least one side of the cylindrical body in the axial direction is provided with the end ring, and the end ring is used to connect the multiple cylindrical layers.

5. The collimator manufacturing method according to claim 1, characterized in that The plurality of pinholes are arranged in a circumferential arrangement around the cylindrical body to form a pinhole ring assembly, and the 3D model includes a plurality of the pinhole ring assemblies arranged at intervals in the axial direction of the cylindrical body.

6. A collimator, which is applicable to an SPECT system, characterized in that, Comprising a cylindrical body, the cylindrical body includes multiple cylindrical layers, the multiple cylindrical layers are concentrically arranged and are sequentially spaced apart in the radial direction of the cylindrical body; a plurality of pinholes are provided on the cylindrical layer, and the plurality of pinholes are obtained by 3D printing in an integral molding manner, and the pinholes sequentially penetrate through the multiple cylindrical layers; The 3D printing integral molding method is to integrally form the cylindrical body and the plurality of pinholes by 3D modeling and selective laser sintering; The sintering material used in the selective laser sintering method is metal; The pinhole includes a first flared section and a second flared section, the first flared section and the second flared section are sequentially connected outward in the radial direction of the cylindrical body, and the radial dimension of the first flared section gradually decreases outward in the radial direction of the cylindrical body, and the radial dimension of the second flared section gradually increases outward in the radial direction of the cylindrical body.

7. A tomographic imaging system, the tomographic imaging system being a SPECT system, characterized in that, Comprising: A collimator, which includes a cylindrical body, the cylindrical body includes multiple cylindrical layers, the multiple cylindrical layers are concentrically arranged and are sequentially spaced apart in the radial direction of the cylindrical body; a plurality of pinholes are provided on the cylindrical layer, and the plurality of pinholes are obtained by 3D printing in an integral molding manner, and the pinholes sequentially penetrate through the multiple cylindrical layers; The detection cylinder is arranged around the collimator; wherein, the detection cylinder includes a plurality of detectors, and the detectors and the pinholes are arranged in alignment along the radial direction of the collimator; The 3D printing integral forming method integrally forms the cylindrical body and the plurality of pinholes through 3D modeling and selective laser sintering method; The sintering material used in the selective laser sintering method is metal; The pinhole includes a first flared section and a second flared section, the first flared section and the second flared section are sequentially connected along the radial direction of the cylindrical body outward, and the radial dimension of the first flared section gradually decreases along the radial direction of the cylindrical body outward, and the radial dimension of the second flared section gradually increases along the radial direction of the cylindrical body outward.

Images