PET detector and system
By employing a stacked crystal array structure and photoelectric sensing layer design in the PET detector, the problem of insufficient DOI spatial resolution was solved, achieving higher spatial resolution and image clarity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 湾影科技(深圳)有限公司
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-12
AI Technical Summary
The insufficient spatial resolution of DOI in existing PET detectors leads to annihilation location reconstruction offset and parallax error, affecting the spatial resolution and image clarity of the PET system.
A stacked crystal array structure is adopted, in which the scintillation crystals of the first and second crystal layers extend in the same direction, and the photoelectric sensing layer is disposed on the side of the second crystal layer away from the first crystal layer. The number ratio of scintillation crystals at different positions is different, and the visible light is accurately detected by the photosensitive device in the photoelectric sensing layer.
This improves the spatial resolution of the DOI of the PET detector, accurately determines the location of the reaction in the crystal array, and enhances the resolution and clarity of the image.
Smart Images
Figure CN122017927A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radiation detector technology, and more particularly to a PET detector and system. Background Technology
[0002] Positron emission tomography (PET) is a novel medical instrument invented in the 1970s and widely used in this century. As the core of a PET system, the gamma-ray detector typically employs a crystal array coupled with position-sensitive optoelectronic devices, combined with Anger logic algorithms to achieve localization within the detector.
[0003] As the performance of modern equipment improves, the requirements for system spatial resolution increase. Current front-end detectors have insufficient depth-of-interaction (DOI) capability, which causes the reconstruction of annihilation locations to be offset, resulting in parallax errors and poor spatial resolution of the PET system. Summary of the Invention
[0004] This invention provides a PET detector and system to improve the DOI spatial resolution of the PET detector and enhance image clarity.
[0005] According to one aspect of the present invention, a PET detector is provided, comprising: a crystal array and a photoelectric sensing layer; The crystal array includes a first crystal layer and a second crystal layer stacked together; the first crystal layer includes a plurality of first scintillation crystals arranged in an array, and the second crystal layer includes a plurality of second scintillation crystals arranged in an array, wherein both the first scintillation crystals and the second scintillation crystals extend along a first direction; wherein the first direction is parallel to the stacking direction. In the first direction, the first crystal layer and the second crystal layer are coupled and bonded together; the photoelectric sensing layer is disposed on the first end face of the second crystal layer on the side away from the first crystal layer. The ratio of the number of the first scintillation crystal to the number of the second scintillation crystal varies at different positions on the first end face.
[0006] Optionally, the number of the first scintillation crystals is less than the number of the second scintillation crystals.
[0007] Optionally, the first end face includes a central region; In the central region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:4.
[0008] Optionally, the first end face includes an edge region; In the edge region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:2.
[0009] Optionally, the first end face includes a apex corner region; In the apex region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:1.
[0010] Optionally, the photoelectric sensing layer includes multiple photoelectric sensors; The multiple photoelectric sensors are arranged in an array, and the ratio of the number of photoelectric sensors to the number of the second scintillation crystal is 1:4.
[0011] Optionally, in the first direction, each of the photoelectric sensors and the present The four second scintillation crystals arranged in the array are configured accordingly; Among them, the four second scintillation crystals are respectively with... The four first scintillation crystals arranged in the array are configured in a one-to-one correspondence.
[0012] Optionally, the materials of both the first scintillation crystal and the second scintillation crystal include sodium thallium iodide crystal, bismuth germanate crystal, lutetium silicate crystal, and lutetium-yttrium silicate crystal.
[0013] Optionally, reflective material is disposed between adjacent first scintillation crystals and between adjacent second scintillation crystals.
[0014] According to another aspect of the present invention, a PET system is provided, including a PET detector as described in any embodiment of the first aspect.
[0015] The PET detector provided in this embodiment of the invention includes a crystal array comprising a first crystal layer and a second crystal layer stacked together. The first crystal layer includes a plurality of first scintillation crystals arranged in a close array, and the second crystal layer includes a plurality of second scintillation crystals arranged in a close array. Both the first and second scintillation crystals are regular square prisms extending along a first direction. A photoelectric sensing layer is disposed on a first end face of the second crystal layer away from the first crystal layer. The photoelectric sensing layer includes a plurality of photosensitive devices arranged in a close array. The photosensitive devices corresponding to adjacent second scintillation crystals may be the same or different, and the corresponding first scintillation crystals may be the same or different. The ratio of the number of first scintillation crystals to second scintillation crystals varies at different positions on the first end face; therefore, the arrangement position of each first scintillation crystal in the first crystal layer differs from the arrangement position of each photosensitive device in the photoelectric sensing layer. This allows visible light emitted from the location where the reaction occurs in the second scintillation crystal to be refracted into the first scintillation crystal and then reflected to the adjacent second scintillation crystal. This enables the reflected visible light to be detected by different photosensitive devices, thereby improving the DOI spatial resolution of the PET detector, accurately determining the specific location of the reaction in the crystal array, and effectively enhancing the clarity of the resolved image.
[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic cross-sectional view of a PET detector according to an embodiment of the present invention; Figure 2 This is a top-view perspective structural diagram of a PET detector according to an embodiment of the present invention; Figure 3 This is a top-view perspective view of the structure of a PET detector from one side of the photoelectric sensing layer, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of an analytical image of a PET detector provided according to an embodiment of the present invention. Detailed Implementation
[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0021] As described in the background section, gamma-ray detectors, as the core of PET systems, typically employ a configuration of crystal arrays coupled with position-sensitive optoelectronic devices, combined with Anger logic algorithms for internal positioning within the detector. The crystal is sized to have sufficient dimensions between its center-facing surface and its sensor-facing surface, allowing photons to interact at a point defined as the depth of interaction. For example, the crystal is typically an elongated rectangular rod, receiving gamma photons at one end and coupled to one or more optical sensors at the opposite end. The optical sensors convert the sensed emission into measurements of the energy and time of the received gamma photons.
[0022] With the improvement of modern equipment performance, the requirements for system spatial resolution have increased, necessitating that the front-end detector possess high DOI resolution capability, i.e., the ability to detect three-dimensional positions. If the front-end detector lacks DOI resolution capability, it can only use the top surface of the crystal unit as the start and end points of the response line, causing a shift in the reconstruction of the annihilation position, i.e., generating parallax error. At the same time, a low DOI resolution capability of the front-end detector will make the image blurry, and the spatial resolution of the PET system will gradually deteriorate from the center to the edge of the field of view (FOV).
[0023] Based on the above-mentioned technical problems, the embodiments of the present invention propose the following technical solutions: This invention provides a PET detector. Figure 1This is a schematic cross-sectional view of a PET detector provided in an embodiment of the present invention. Figure 2 This is a top-view perspective structural diagram of a PET detector provided in an embodiment of the present invention. (Combined with...) Figure 1 and Figure 2 The PET detector includes a crystal array 100 and a photoelectric sensing layer 200.
[0024] The crystal array 100 includes a first crystal layer 101 and a second crystal layer 102 stacked together; the first crystal layer 101 includes a plurality of first scintillation crystals 103 arranged in an array, and the second crystal layer 102 includes a plurality of second scintillation crystals 104 arranged in an array, wherein the first scintillation crystals 103 and the second scintillation crystals 104 both extend along a first direction; wherein the first direction is parallel to the stacking direction. In the first direction, the first crystal layer 101 and the second crystal layer 102 are coupled and bonded together; the photoelectric sensing layer 200 is disposed on the first end face 105 of the second crystal layer 102 on the side away from the first crystal layer 101. The ratio of the number of the first scintillation crystal 103 to the number of the second scintillation crystal 104 is different at different positions on the first end face 105.
[0025] Specifically, the PET detector includes a crystal array 100 and a photoelectric sensing layer 200 disposed on the side of the crystal array 100 opposite to the light-incident surface. Gamma photons are incident from the light-incident surface of the crystal array 100 and react at corresponding positions within the crystal array 100, converting into visible light. The visible light propagates out of the crystal array 100 and is detected by the photoelectric sensing layer 200, thus forming a resolving image. The location of the reaction in the crystal array 100 can then be determined based on the resolving image. Since one photosensitive element in the photoelectric sensing layer 200 can be coupled to multiple crystal strips in the crystal array 100, the location of the reaction in multiple different crystal strips corresponding to the same photosensitive element cannot be accurately determined by the resolving image formed after detection by a single photosensitive element. This results in a certain parallax error, meaning the DOI resolution of the PET detector is insufficient, the image is blurry, and the spatial resolution of the PET system is poor.
[0026] In this embodiment of the invention, the crystal array 100 includes two stacked crystal array layers, namely a first crystal layer 101 and a second crystal layer 102. Each crystal array layer contains multiple crystals; specifically, the first crystal layer 101 contains multiple first scintillation crystals 103 arranged in an array, and the second crystal layer 102 contains multiple second scintillation crystals 104 arranged in an array. Both the first scintillation crystals 103 and 104 are in the shape of regular square prisms, with their side edges parallel to a first direction, meaning they extend along the first direction and are generally strip-shaped. In a plane perpendicular to the first direction, the first scintillation crystals 103 are arranged in a dense array in the first crystal layer 101, and the second scintillation crystals 104 are arranged in a dense array in the second crystal layer 102. Exemplarily, the first direction can be... Figure 1 The Y direction in the figure represents, while Figure 2 In the top view of the detector shown, the first direction is perpendicular to the paper and pointing inwards. The first crystal layer 101 and the second crystal layer 102, which are stacked together, are coupled and bonded together, with the first crystal layer 101 located closer to the incident surface and the second crystal layer 102 located farther from the incident surface. Exemplarily, transparent optical adhesive, gel, or transparent silicone grease can be used to achieve the coupling and bonding of the first crystal layer 101 and the second crystal layer 102. The second crystal layer 102 includes a first end face 105 on the side farther from the first crystal layer 101. The photoelectric sensing layer 200 is disposed on the first end face 105, and the photoelectric sensing layer 200 is also coupled and bonded to the first end face 105 using transparent optical adhesive. Using transparent adhesive in this way not only achieves bonding of the first crystal layer 101 and the second crystal layer 102 together but also ensures normal photon transmission without affecting light propagation. By setting a first crystal layer 101 and a second crystal layer 102 in the crystal array 100, some of the visible light emitted from the position where the reaction occurs in the second crystal layer 102 is refracted to the corresponding first scintillation crystal 103 in the first crystal layer 101, and the refracted visible light is reflected by the first scintillation crystal 103 to the second scintillation crystal 104 adjacent to the position where the reaction occurs, and finally detected by the photosensitive device corresponding to the second scintillation crystal 104.
[0027] The number of first scintillation crystals 103 in the first crystal layer 101 differs from the number of second scintillation crystals 104 in the second crystal layer 102. However, since both the first crystal layer 101 and the second crystal layer 102 are densely arrayed, the sizes of the first scintillation crystals 103 and the second scintillation crystals 104 are different. The photosensitive devices in the photoelectric sensing layer 200 are densely arranged on the first end face 105 of the second crystal layer 102, such that each second scintillation crystal 104 in the second crystal layer 102 is coupled to the same or different photosensitive devices. At different orthographic projection positions on the first end face 105, one first scintillation crystal 103 in the first crystal layer 101 corresponds to a different number of second scintillation crystals 104 in the second crystal layer 102. This allows the arrangement of the first scintillation crystals 103 in the first crystal layer 101 to be at least partially different from the arrangement of the photosensitive devices in the photoelectric sensing layer 200. Visible light emitted from the position where the reaction occurs in the second scintillation crystal 104 is refracted into the first scintillation crystal 103 and reflected to the adjacent second scintillation crystal 104. Thus, the reflected visible light can be detected by different photosensitive devices, thereby improving the depth-of-field resolution (DOI) of the PET detector, accurately determining the specific position where the reaction occurs in the crystal array 100, and effectively improving the clarity of the resolved image.
[0028] The PET detector provided in this embodiment of the invention includes a crystal array 100 comprising a first crystal layer 101 and a second crystal layer 102 stacked together. The first crystal layer 101 includes a plurality of first scintillation crystals 103 arranged in a close array, and the second crystal layer 102 includes a plurality of second scintillation crystals 104 arranged in a close array. Both the first scintillation crystals 103 and 104 are regular square prisms extending along a first direction. A photoelectric sensing layer 200 is disposed on a first end face 105 of the second crystal layer 102 away from the first crystal layer 101. The photoelectric sensing layer 200 includes a plurality of photosensitive devices arranged in a close array. The photosensitive devices corresponding to adjacent second scintillation crystals 104 may be the same or different, and the corresponding first scintillation crystals 103 may be the same or different. At different positions on the first end face 105, the ratio of the number of first scintillation crystals 103 to second scintillation crystals 104 is different. Therefore, the arrangement position of each first scintillation crystal 103 in the first crystal layer 101 is different from the arrangement position of each photosensitive device in the photoelectric sensing layer 200. This allows visible light emitted from the location where the reaction occurs in the second scintillation crystal 104 to be refracted into the first scintillation crystal 103 and then reflected to the adjacent second scintillation crystal 104. This enables the reflected visible light to be detected by different photosensitive devices, thereby improving the DOI spatial resolution of the PET detector, accurately determining the specific location where the reaction occurs in the crystal array 100, and effectively improving the clarity of the resolved image.
[0029] Based on the above embodiments, Figure 3 This is a top-view perspective structural diagram of a PET detector from one side of the photoelectric sensing layer, according to an embodiment of the present invention. (See also...) Figure 3 Optionally, the photoelectric sensing layer 200 includes a plurality of photoelectric sensors 201.
[0030] Multiple photoelectric sensors 201 are arranged in an array, and the ratio of the number of photoelectric sensors 201 to the number of the second scintillation crystal 104 is 1:4.
[0031] Specifically, the photoelectric sensing layer 200 may include multiple photoelectric sensors 201 of the same size, and the multiple photoelectric sensors 201 are arranged in a dense array on one side of the first end face 105 of the second crystal layer 102, such that each second scintillation crystal 104 is correspondingly coupled to one photoelectric sensor 201. For example, the photoelectric sensor 201 may include a photomultiplier tube (PMT) or a silicon photomultiplier tube (SiPM), without limitation. The surface of the photoelectric sensor 201 corresponding to the first end face 105 is square, and the size of one photoelectric sensor 201 is a multiple of the size of the second scintillation crystal 104. Therefore, one photoelectric sensor 201 can be correspondingly coupled to one of the second scintillation crystals 104 on the first end face 105. Multiple second scintillation crystals 104 are arranged in a specific pattern. Exemplarily, in an embodiment of the invention, a photoelectric sensor 201 and a second crystal layer 102 are arranged in a specific pattern. Corresponding couplings in close-packed forms. See also Figure 3 The regions divided by the red inner border lines within the array represent the densely packed array of photoelectric sensors 201. For example, the second scintillation crystal 104 in the second crystal layer 102 provided in this embodiment of the invention is... In the array configuration, photoelectric sensors 201 are densely packed on one side of the first end face 105. An array-shaped photoelectric sensing layer 200. It can be seen that one photoelectric sensor 201 can be coupled to four adjacent second scintillation crystals 104. Therefore, the ratio of the number of photoelectric sensors 201 in the photoelectric sensing layer 200 to the number of second scintillation crystals 104 in the second crystal layer 102 is 1:4.
[0032] Based on the above embodiments, see below. Figure 1 and Figure 2 Optionally, the number of first scintillation crystals 103 is less than the number of second scintillation crystals 104.
[0033] Specifically, by setting the number of first scintillation crystals 103 to be less than the number of second scintillation crystals 104, the size of the first scintillation crystals 103 is at least partially larger than the size of the second scintillation crystals 104. This allows the first scintillation crystals 103 to still closely couple with the second scintillation crystals 104 even when their number is relatively small. By setting the number of first scintillation crystals 103 to be less than the number of second scintillation crystals 104, at least some of the first scintillation crystals 103 can correspond to multiple second scintillation crystals 104, thereby improving the spectral dispersion effect of the crystal array 100 on the visible light emitted from the reaction location and increasing the DOI spatial resolution of the PET detector.
[0034] Based on the above embodiments, see below. Figure 2 and Figure 3 Optionally, the first end face 105 includes a central region 1051.
[0035] In the central region 1051, the ratio of the number of the first scintillation crystal 103 to the number of the second scintillation crystal 104 is 1:4.
[0036] Specifically, in the first end face 105 In the central region 1051 of the array, the size of the first scintillation crystal 103 is twice that of the second scintillation crystal 104. Therefore, one first scintillation crystal 103 corresponds to four scintillation crystals. The second scintillation crystal 104 is arranged in an array. Combined with... Figure 2 and Figure 3 It can be seen that in the central region 1051, each of the first scintillation crystals 103 in the first crystal layer 101 located on the side of the second crystal layer 102 away from the first end face 105 is arranged alternately with each of the photoelectric sensors 201 in the photoelectric sensing layer 200 located on the side of the second crystal layer 102 close to the first end face 105.
[0037] Based on the above embodiments, see below. Figure 2 and Figure 3 Optionally, in the first direction, each photoelectric sensor 201 and the... The four second scintillation crystals 104 arranged in the array are set accordingly; Among them, the four second scintillation crystals 104 are respectively with... The four first scintillation crystals 103 arranged in the array are set up one-to-one.
[0038] For example, the orthographic projection of a first scintillation crystal 103 on the first end face 105 partially overlaps with the orthographic projection of a corresponding photoelectric sensor 201 on the first end face 105. Combined Figure 2 and Figure 3It can be seen that the orthographic projection of a first scintillation crystal 103 on the first end face 105 overlaps with the orthographic projection of a corresponding photoelectric sensor 201 on the first end face 105 by one-quarter of the area. Therefore, the orthographic projection of a first scintillation crystal 103 on the first end face 105 can overlap with the orthographic projection of the corresponding photoelectric sensor 201 on the first end face 105. The four photoelectric sensors 201 arranged in the array each have a quarter of their overlapping area. Alternatively, it can be said that the orthographic projection of one photoelectric sensor 201 onto the first end face 105 can be perpendicular to the corresponding sensor. The four first scintillation crystals 103 arranged in the array each have a quarter of their overlapping area; and in the central region 1051, one first scintillation crystal 103 is correspondingly coupled to form a certain shape. Four second scintillation crystals 104 are arranged in an array. This allows the resolved image generated by the PET detector to present a four-cornered quincunx pattern. For example, Figure 4 This is a schematic diagram of an analyzed image of a PET detector provided in an embodiment of the present invention. See also... Figure 4 The resolved image in the central region is a four-cornered scintillation pattern, where the central "stamen" corresponds to the first scintillation crystal 103 in the first crystal layer 101, and the four surrounding "petals" correspond to the four coupled second scintillation crystals 104. By setting two crystal layers, with different crystal strip sizes between the first crystal layer 101 and the second crystal layer 102, and with the first scintillation crystal 103 corresponding to four different photoelectric sensors 201, it is beneficial to accurately determine the location of the reaction in the crystal array 100, effectively improving the DOI spatial resolution of the PET detector and enhancing image clarity.
[0039] Based on the above embodiments, see below. Figure 2 and Figure 3 Optionally, the first end face 105 includes an edge region 1052.
[0040] In the edge region 1052, the ratio of the number of the first scintillation crystal 103 to the number of the second scintillation crystal 104 is 1:2.
[0041] Specifically, the edge region 1052 is located at the outer edge of the four sides of the central region 1051. The first scintillation crystal 103 is a tetrahedral prism shape rather than a regular tetrahedral prism shape, and the aspect ratio of the first scintillation crystal 103 is 1:2, meaning that one first scintillation crystal 103 corresponds to two adjacent second scintillation crystals 104. See also... Figure 3The orthographic projections of the two second scintillation crystals 104 on the first end face 105 overlap with the orthographic projections of two adjacent different photoelectric sensors 201 on the first end face 105. In other words, one first scintillation crystal 103 corresponds to a portion of the area of two adjacent different photoelectric sensors 201. Thus, visible light separated by the same first scintillation crystal 103 can be detected by different photoelectric sensors 201, thereby improving the beam splitting effect and enhancing the DOI spatial resolution of the PET detector.
[0042] Based on the above embodiments, see below. Figure 2 and Figure 3 Optionally, the first end face 105 includes a apex corner region 1053.
[0043] In the apex region 1053, the ratio of the number of the first scintillation crystal 103 to the number of the second scintillation crystal 104 is 1:1.
[0044] Specifically, the apex region 1053 is located at the outer positions of the four apex corners of the central region 1051. The size of the first scintillation crystal 103 disposed in the apex region 1053 is the same as the size of the corresponding second scintillation crystal 104. Therefore, in the apex region 1053, one first scintillation crystal 103 is coupled to one second scintillation crystal 104. See also... Figure 3 The orthographic projection of a second scintillation crystal 104 on the first end face 105 overlaps with a quarter portion of the orthographic projection of a photoelectric sensor 201 on the first end face 105. That is, a first scintillation crystal 103 corresponds to a quarter region of a photoelectric sensor 201. In summary, a first scintillation crystal 103 in the central region 1051 is thus coupled to... The array of four second scintillation crystals 104, one first scintillation crystal 103 in the edge region 1052 coupled to two adjacent second scintillation crystals 104, and one first scintillation crystal 103 in the apex region 1053 coupled to one second scintillation crystal 104, allows the PET detector to obtain a four-cornered quincunx pattern of the resolved image of the central region 1051, thereby improving the beam splitting effect, which is beneficial to improving the DOI spatial resolution of the PET detector and obtaining a clearer image.
[0045] Exemplarily, the materials of the first scintillation crystal 103 and the second scintillation crystal 104 include sodium iodide crystal, bismuth germanate crystal, lutetium silicate crystal, and lutetium-yttrium silicate crystal, but are not limited to the above-mentioned types of materials. For example, in this embodiment of the invention, the first scintillation crystal 103 and the second scintillation crystal 104 are made of lutetium-yttrium silicate crystal (LYSO), which is not limited here. Furthermore, an aluminum foil of a certain thickness, such as 0.05 mm, can be used to wrap the outside of the PET detector to protect the first crystal layer 101 and the second crystal layer 102.
[0046] It should be noted that the height of the first scintillation crystal 103 in the first crystal layer 101 and the height of the second scintillation crystal 104 in the second crystal layer 102 can be arbitrarily set.
[0047] Based on the above embodiments, optionally, reflective material is provided between adjacent first scintillation crystals 103 and between adjacent second scintillation crystals 104.
[0048] For example, the reflective material may include a highly reflective material, such as barium sulfate. In this embodiment of the invention, barium sulfate is used to fill the gaps between adjacent first scintillation crystals 103 in the first crystal layer 101 and between adjacent second scintillation crystals 104 in the second crystal layer 102, thereby collecting as much divergent visible light emitted from the reaction site as possible, which is beneficial to improving the DOI spatial resolution of the PET detector and enhancing image clarity.
[0049] This invention also provides a PET system. This PET system includes a PET detector as provided in any of the above embodiments, and has similar functional principles and beneficial effects to the PET detector, which will not be elaborated upon here.
[0050] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A PET detector, characterized in that, include: Crystal array and photoelectric sensing layer; The crystal array includes a first crystal layer and a second crystal layer stacked together; the first crystal layer includes a plurality of first scintillation crystals arranged in an array, and the second crystal layer includes a plurality of second scintillation crystals arranged in an array, wherein both the first scintillation crystals and the second scintillation crystals extend along a first direction; wherein the first direction is parallel to the stacking direction. In the first direction, the first crystal layer and the second crystal layer are coupled and bonded together; the photoelectric sensing layer is disposed on the first end face of the second crystal layer on the side away from the first crystal layer. The ratio of the number of the first scintillation crystal to the number of the second scintillation crystal varies at different positions on the first end face.
2. The PET detector according to claim 1, characterized in that, The number of the first scintillation crystals is less than the number of the second scintillation crystals.
3. The PET detector according to claim 2, characterized in that, The first end face includes a central region; In the central region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:
4.
4. The PET detector according to claim 2, characterized in that, The first end face includes an edge region; In the edge region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:
2.
5. The PET detector according to claim 2, characterized in that, The first end face includes a apex corner region; In the apex region, the ratio of the first scintillation crystal to the second scintillation crystal is 1:
1.
6. The PET detector according to claim 1, characterized in that, The photoelectric sensing layer includes multiple photoelectric sensors; The multiple photoelectric sensors are arranged in an array, and the ratio of the number of photoelectric sensors to the number of the second scintillation crystal is 1:
4.
7. The PET detector according to claim 6, characterized in that, In the first direction, each of the photoelectric sensors and the present The four second scintillation crystals arranged in the array are configured accordingly; Among them, the four second scintillation crystals are respectively with... The four first scintillation crystals arranged in the array are configured in a one-to-one correspondence.
8. The PET detector according to claim 1, characterized in that, The materials of both the first scintillation crystal and the second scintillation crystal include sodium thallium iodide crystal, bismuth germanate crystal, lutetium silicate crystal, and lutetium-yttrium silicate crystal.
9. The PET detector according to claim 1, characterized in that, Reflective material is disposed between adjacent first scintillation crystals and between adjacent second scintillation crystals.
10. A PET system, characterized in that, Including the PET detector as described in any one of claims 1-9.