Gamma camera with collimating unit

Abstract

The disclosure provides a gamma camera with a collimation unit, which can be applied to the technical field of detection. The gamma camera comprises at least one detection unit, and the detection unit comprises: a collimation unit, the collimation unit comprises a plurality of needle collimator arrays staggered with each other, each needle collimator array comprises a plurality of needle collimators arranged in an array and each having a length direction pointing in the same direction, and the length directions of the needle collimators in different needle collimator arrays point in different directions; a plurality of scintillation crystal units for detecting gamma photons penetrating the collimation unit in different directions and generating a plurality of groups of scintillation light signals; and a plurality of photoelectric conversion units, each of which is coupled to a scintillation crystal unit and used for converting the plurality of groups of scintillation light signals into a plurality of groups of electric signals for imaging of the gamma camera.

Description

Technical Field

[0001] At least one embodiment of this disclosure relates to the field of detection technology, and more specifically to a gamma camera with a collimation unit. Background Technology

[0002] A gamma camera is a device used to detect and locate gamma radiation sources, and it is widely used in industrial, medical imaging, and customs security inspection fields. Due to the complexity of different application scenarios and diverse requirements, different requirements are placed on the detection sensitivity and imaging performance of gamma rays. Currently, a single gamma camera system cannot simultaneously meet all these requirements.

[0003] With continuous technological advancements, a gamma camera imaging method based on the principle of "self-collimation" has been proposed. Patent document CN111329500A proposes that a multi-layer detector unit acts as a photon collimator for subsequent detector units, improving the photon direction collimator effect and simultaneously increasing the system's sensitivity. Furthermore, patent document CN114010211A suggests filling the scintillation crystal array of the detection collimation unit with materials such as resin, polyethylene plastic, plexiglass, and heavy metals, which can improve the system's image quality and achieve higher-quality gamma radiation source imaging.

[0004] In gamma imaging, the aim is to use a detector to receive gamma photons incident from different directions, noting that different locations produce different responses. The location of the gamma radiation source is then determined based on the differences in these responses. Traditional methods place the collimator in front of the detector, which suffers from limitations in detection efficiency and field of view. While the aforementioned "self-collimation" method uses multiple layers of crystal units to create different responses by blocking each other, thus avoiding a decrease in detection efficiency, it struggles to achieve effective collimation and response differences for high-energy gamma rays that penetrate more strongly. Summary of the Invention

[0005] In view of the above problems, this disclosure provides a gamma camera with a collimation unit. The gamma camera includes at least one detection unit, which includes: a collimation unit comprising a plurality of staggered arrays of needle-type collimators, each array comprising a plurality of arrayed needle-type collimators whose length directions point in the same direction, the length directions of the needle-type collimators in different arrays pointing in different directions; wherein the efficiency of blocking gamma photons incident along the length direction of the needle-type collimator is a first blocking efficiency; the efficiency of blocking gamma photons incident along a length direction perpendicular to the length direction of the needle-type collimator is a second blocking efficiency; wherein the first blocking efficiency is greater than the second blocking efficiency; a plurality of scintillation crystal units for detecting gamma photons penetrating the collimation unit along different directions and generating multiple sets of scintillation light signals; and a plurality of photoelectric conversion units, each connected to the scintillation crystal units, for converting the multiple sets of scintillation light signals into multiple sets of electrical signals for imaging by the gamma camera.

[0006] According to embodiments of this disclosure, the first blocking efficiency is greater than 70%.

[0007] According to embodiments of this disclosure, the second blocking efficiency is less than 20%.

[0008] According to embodiments of this disclosure, the material of the needle collimator includes crystals or metals.

[0009] According to an embodiment of the present disclosure, the collimation unit further includes a support structure. Based on the support structure, the collimation unit forms a spatial polyhedron, and the plurality of scintillation crystal units are respectively disposed on the plurality of faces of the spatial polyhedron.

[0010] According to embodiments of this disclosure, the above-described support structure attenuates less than 30% of gamma photons incident at any angle.

[0011] According to an embodiment of this disclosure, the photoelectric conversion unit is coupled to the side of the scintillation crystal unit.

[0012] According to an embodiment of the present disclosure, the collimation unit includes a plurality of needle collimator arrays arranged in three different directions, the three different directions being perpendicular to each other.

[0013] According to an embodiment of this disclosure, the at least one detection unit is arranged in a first combination in space, wherein the ratio of the maximum to the minimum number of detection units arranged in three different directions is less than or equal to 1.5.

[0014] According to embodiments of this disclosure, at least two detection units are arranged in a second combination in space, wherein the ratio of the maximum to the minimum number of detection units arranged in three different directions is greater than 1.5. Attached Figure Description

[0015] The foregoing contents, other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of this disclosure with reference to the accompanying drawings.

[0016] Figure 1 A schematic diagram of a gamma camera according to an embodiment of the present disclosure is shown.

[0017] Figure 2A A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0018] Figure 2B A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0019] Figure 2C A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0020] Figure 2D A schematic diagram of a needle collimator according to an embodiment of the present disclosure is shown.

[0021] Figure 3A A schematic diagram of a detection unit according to an embodiment of the present disclosure is shown.

[0022] Figure 3B A schematic diagram of a needle collimator according to an embodiment of the present disclosure is shown.

[0023] Figure 3C A schematic diagram of a scintillation crystal unit according to an embodiment of the present disclosure is shown.

[0024] Figure 4 A schematic diagram of a gamma camera according to yet another embodiment of the present disclosure is shown.

[0025] Figure 5A A schematic diagram of a gamma camera according to another embodiment of the present disclosure is shown.

[0026] Figure 5B A schematic diagram of a gamma camera according to another embodiment of the present disclosure is shown. Detailed Implementation

[0027] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0031] Figure 1 A schematic diagram of a gamma camera according to an embodiment of the present disclosure is shown.

[0032] like Figure 1 As shown, the gamma camera 100 includes at least one detection unit 110. The detection unit 110 includes a collimation unit 111, a plurality of scintillation crystal units 112, and a plurality of photoelectric conversion units 113.

[0033] The collimation unit 111 includes multiple needle-type collimator arrays arranged in an alternating manner. Each needle-type collimator array includes multiple needle-type collimators 111a arranged in an array, with their respective length directions pointing in the same direction. The length directions of the needle-type collimators 111a in different needle-type collimator arrays point in different directions.

[0034] Figure 2A A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0035] Figure 2B A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0036] Figure 2C A schematic diagram of a needle collimator array according to an embodiment of the present disclosure is shown.

[0037] Figure 2D A schematic diagram of a needle collimator according to an embodiment of the present disclosure is shown.

[0038] In one example, such as Figure 2A As shown, the first needle-type collimator array 111A includes multiple needle-type collimators 111a arranged in an array, each with its length direction pointing towards the vicinity of the X direction. Figure 2B As shown, the second needle-type collimator array 111B includes multiple needle-type collimators 111a arranged in an array, each with its length direction pointing towards the vicinity of the Y direction. Figure 2C As shown, the third needle-type collimator array 111C includes multiple needle-type collimators 111a arranged in an array, each with its length direction pointing near the Z direction. Figure 1 As shown, the collimation unit 111 includes a first needle-type collimator array 111A, a second needle-type collimator array 111B, and a third needle-type collimator array 111C arranged alternately with each other.

[0039] The efficiency with which gamma photons incident on the needle collimator 111a along its length are blocked is called the first blocking efficiency. For example... Figure 2D As shown, the efficiency at which gamma photons incident on the needle-type collimator 111a along its length direction perpendicular to the needle collimator 111a is blocked is called the second blocking efficiency. The first blocking efficiency is greater than the second blocking efficiency. Multiple scintillation crystal units 112 are used to detect gamma photons penetrating the collimator unit 111 along different directions, generating multiple sets of scintillation light signals. Each photoelectric conversion unit 113 is connected to the scintillation crystal unit 112 and is used to convert the multiple sets of scintillation light signals into multiple sets of electrical signals for imaging with a gamma camera.

[0040] Different needle-type collimator arrays can be arranged in multiple preset directions within three-dimensional space. The length directions of the needle-type collimators 111a in different arrays point in different directions. Multiple needle-type collimator arrays are arranged in an alternating pattern, with all needle-type collimators 111a not in contact. The needle-type collimators 111a can be made of suitable materials and have appropriate sizes based on the nuclide detection energy range of gamma photons.

[0041] Multiple scintillation crystal units 112 are randomly distributed outside the three-dimensional space occupied by multiple needle-type collimator arrays. Crystal arrays can be constructed on each surface outside this three-dimensional space to form scintillation crystal units 112. Gamma photons passing through collimator units 111 directly strike the incident surface of the scintillation crystal unit 112, and the crystal arrays on the incident surface of the scintillation crystal unit 112 can all be collimated by needle-type collimators 111a in different directions. During the design of the needle-type collimators 111a, scintillation crystal units 112 and collimator units 111 can be set within the three-dimensional space. The length direction of the needle-type collimators 111a in different needle-type collimator arrays points to multiple incident surfaces, and the needle-type collimators 111a are randomly arranged.

[0042] According to embodiments of this disclosure, the needle collimator is arranged in a specific pattern in space, which can effectively collimate multiple scintillation crystal units in space. This allows for the maximization of the utilization of the scintillation crystal units and photoelectric conversion units to obtain different response information differences, thus enabling more efficient gamma-ray imaging.

[0043] According to embodiments of this disclosure, the first blocking efficiency is greater than 70%. The second blocking efficiency is less than 20%.

[0044] The blocking efficiency of gamma photons incident along the length of the needle collimator exceeds 70% (referred to as the high blocking direction), while the blocking efficiency of gamma photons incident along the direction perpendicular to the length of the needle collimator is less than 20% (referred to as the low blocking direction). The blocking efficiency of gamma photons incident along other directions ranges from 20% to 70%. The needle collimators are arranged in an array along multiple selected directions. The high blocking directions of the needle collimators in each array are oriented in the same direction. Overall, the arrays of needle collimators with different high blocking directions are staggered in space, so that the high blocking directions of the needle collimators are aligned in various directions, which can effectively collimate gamma photons incident from any field of view.

[0045] According to embodiments of this disclosure, the material of the needle collimator can be either crystal or metal. When the material of the needle collimator is chosen to be crystal, such as a scintillation crystal, the needle collimator can not only be used for collimation but also serve as a receiver for detection.

[0046] After determining the energy of the incident gamma photon, the parameters of a single needle collimator can be set.

[0047] Figure 3A A schematic diagram of a detection unit according to an embodiment of the present disclosure is shown.

[0048] Figure 3B A schematic diagram of a needle collimator according to an embodiment of the present disclosure is shown.

[0049] Figure 3CA schematic diagram of a scintillation crystal unit according to an embodiment of the present disclosure is shown.

[0050] like Figure 3A As shown, the spatial dimensions of the detection unit can be set to 50mm*50mm*50mm. For the 662keV energy of cesium (Cs)-137 nuclide, a tungsten metal material with a height of 10mm and a length and width of 2mm can be used as a single needle-shaped collimator, such as... Figure 3B As shown. A scintillation crystal unit can be a single scintillation crystal or a crystal array; it can include only one material or multiple materials. For example, as... Figure 3C As shown, the scintillation crystal unit comprises two crystal arrays, one of which is made of BGO (Bi4Ge3O4). 12 The other layer of the crystal array is made of bismuth germanate crystal, and the material of the other crystal array is GAGG(Ce). GAGG(Ce) represents cerium-doped (Ce) gadolinium aluminum gallium garnet (Gd3Al2Ga3O). 12 The size of a single crystal can be set to 3mm*3mm*3mm.

[0051] According to embodiments of this disclosure, a suitable collimating material is selected based on the nuclide detection energy range. The parameters of the needle collimator are selectively designed to adapt to different energy incident gamma photons, based on the application requirements of the gamma camera. For gamma cameras receiving low-energy gamma photons, a needle collimator made of scintillation crystal can be selected, which can both achieve ray collimation and improve detection efficiency. For gamma cameras receiving high-energy gamma photons, a needle collimator made of metallic material is selected, which expands both the gamma photon energy detection range and the applicability of the device.

[0052] According to embodiments of the present disclosure, the collimation unit further includes a support structure, and based on the support structure, the collimation unit forms a spatial polyhedron, with multiple scintillation crystal units respectively disposed on multiple faces of the spatial polyhedron.

[0053] The supporting structure can be made of lightweight materials, such as PVC, to reduce the attenuation of gamma photons. 3D printing technology can be used to fix the collimating units within the three-dimensional space, forming a spatial hexahedron. Needle-shaped collimators can be arranged in as many directions as possible within the three-dimensional space of the hexahedron, ensuring that the attenuation of gamma photons incident at any angle by the supporting structure does not exceed 30%.

[0054] In one example, the spatial polyhedron can be a spatial hexahedron. Within the three-dimensional space of the spatial hexahedron, a similar number of scintillation crystal units and collimation units are set, and needle collimators are arranged at random positions along the incident planes in the X, Y, and Z directions. The incident planes of the crystal arrays on the six faces of the spatial hexahedron can be collimated by needle collimators in different directions. The scintillation crystal units on the six faces of the spatial hexahedron and all the needle collimators within the three-dimensional space constitute a single detection unit, capable of imaging a gamma source within a panoramic field of view. The gamma camera designed in this way possesses both high- and low-energy wide-range detection capabilities and full-field-of-view 4π imaging capability.

[0055] According to embodiments of this disclosure, the photoelectric conversion unit is coupled to the side of the scintillation crystal unit; or the photoelectric conversion unit is coupled to a spatial hexahedron. In each detection unit, the photoelectric conversion unit can be coupled to the side of the scintillation crystal unit or coupled to the three-dimensional spatial surface of the detection unit. The photoelectric conversion unit can directly couple and read out electrical signals on each surface and transmit them to the imaging unit of the gamma camera for imaging.

[0056] According to embodiments of this disclosure, the collimation unit includes multiple arrays of needle-shaped collimators arranged along three different directions, which are perpendicular to each other. The needle-shaped collimators are constructed with high-blocking directions arranged along three perpendicular three-dimensional directions, such that the arrays are staggered but do not overlap. Figure 2A As shown, the length direction of all needle collimators 111a in the first needle collimator array 111A points to the X direction; as Figure 2B As shown, the length direction of all needle collimators 111a in the second needle collimator array 111B points to the Y direction; as Figure 2C As shown, the length direction of all needle collimators 111a in the third needle collimator array 111C points to the Z direction.

[0057] At least one detection unit of the gamma camera is in multiple combinations in space.

[0058] Figure 4 A schematic diagram of a gamma camera according to yet another embodiment of the present disclosure is shown.

[0059] like Figure 4 As shown, at least one detection unit of the gamma camera is arranged in a first combination in space. In this first combination, the ratio of the maximum to the minimum number of detection units 110 arranged in three different directions is less than or equal to 1.5. Multiple detection units 110 can be arranged in different combinations in space. The detection units 110 are arranged as isotropic as possible, and they can also collimate with each other, resulting in a relatively uniform system resolution across all fields of view and improving the imaging performance of the gamma camera in a panoramic 4π field of view.

[0060] Figure 5A A schematic diagram of a gamma camera according to another embodiment of the present disclosure is shown.

[0061] Figure 5B A schematic diagram of a gamma camera according to another embodiment of the present disclosure is shown.

[0062] At least two detector units of the gamma camera are arranged in a second configuration in space. In this second configuration, the ratio of the maximum to the minimum number of detector units arranged along three different directions is greater than 1.5. Arranging multiple detector units along a predetermined X-ray source direction allows the gamma camera to be more sensitive to changes in gamma photons from that direction, providing ultra-high angular resolution. In the second configuration, multiple sets of detector units can be closely arranged along the predetermined X-ray source direction, such as... Figure 5A As shown; multiple sets of detection units can also be arranged along the preset direction of the radiation source, with gaps between adjacent sets of detection units, such as... Figure 5B As shown.

[0063] By combining different arrangement methods, higher resolution performance can be achieved in a specified direction according to specific needs, thereby improving the imaging flexibility and positioning accuracy of the gamma camera. For example, if the number of detector units is similar in all directions, the combined detector can have a relatively uniform system resolution within a panoramic 4π field of view. Conversely, arranging more detector units along a specified direction results in a relatively higher system resolution within a smaller field of view forward along that direction. By adjusting the combination methods and numbers, imaging requirements for different scenarios can also be met.

[0064] The gamma camera of this disclosure determines the appropriate material and size of the needle collimator based on the detection energy range and the size of the detection unit; multiple needle collimators are arranged in an array with staggered placement along the X, Y, and Z directions; a crystal array is placed outside the detection unit so that gamma photons incident on the crystal array from the three directions can be collimated; the detection units are arranged and combined in different patterns so that the system resolution of the gamma camera is relatively uniform in all directions of the full field of view, thereby improving the flexibility of the gamma camera's imaging mode.

[0065] The gamma camera of this disclosure is applicable to systems with multiple or multiple layers of scintillation crystal detector units, such as those using scintillators and metals arranged in a specific pattern in space. By designing collimating materials of a specific shape, collimating units are formed that have a strong collimation effect in a designated direction and a weaker collimation effect in other directions, while also effectively collimating the scintillation crystal units in space. Designing a specific collimating unit array for spatial distribution in this way enables the gamma camera to effectively collimate the incident direction of radiation sources within the panoramic field of view in space and form a specific detector response, thereby improving the overall performance of the gamma camera.

[0066] Those skilled in the art will understand that the features described in the various embodiments of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0067] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A gamma camera equipped with a collimation unit, characterized in that, The gamma camera includes at least one detection unit, the detection unit comprising: A collimation unit includes multiple needle-type collimator arrays arranged in an alternating pattern. Each needle-type collimator array includes multiple needle-type collimators arranged in an array, with their respective length directions pointing in the same direction. The length directions of the needle-type collimators in different arrays point in different directions. The efficiency at which gamma photons incident along the length direction of the needle-type collimator are blocked is defined as a first blocking efficiency. The efficiency at which gamma photons incident along a direction perpendicular to the length direction of the needle-type collimator are blocked is defined as a second blocking efficiency. The first blocking efficiency is greater than the second blocking efficiency. Multiple scintillation crystal units are used to detect gamma photons that penetrate the collimation unit in different directions, generating multiple sets of scintillation light signals; Multiple photoelectric conversion units, each coupled to the scintillation crystal unit, are used to convert the multiple sets of scintillation light signals into multiple sets of electrical signals for imaging with a gamma camera.

2. The gamma camera according to claim 1, characterized in that, The first blocking efficiency is greater than 70%.

3. The gamma camera according to claim 1, characterized in that, The second blocking efficiency is less than 20%.

4. The gamma camera according to claim 1, characterized in that, The material of the needle collimator includes crystals or metals.

5. The gamma camera according to claim 1, characterized in that, The collimation unit further includes a support structure. Based on the support structure, the collimation unit forms a spatial polyhedron, and the plurality of scintillation crystal units are respectively disposed on the plurality of faces of the spatial polyhedron.

6. The gamma camera according to claim 5, characterized in that, The support structure attenuates less than 30% of gamma photons incident at any angle.

7. The gamma camera according to claim 1, characterized in that, The photoelectric conversion unit is coupled to the side of the scintillation crystal unit.

8. The gamma camera according to claim 1, characterized in that, The collimation unit includes an array of multiple needle collimators arranged in three different directions, which are perpendicular to each other.

9. The gamma camera according to claim 8, characterized in that, The at least one detection unit is arranged in a first combination in space, wherein the ratio of the maximum to the minimum number of detection units arranged in three different directions is less than or equal to 1.

5.

10. The gamma camera according to claim 8, characterized in that, At least two detection units are arranged in a second combination in space, and in the second combination, the ratio of the maximum to the minimum number of detection units arranged in three different directions is greater than 1.5.

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