Combined imaging detector module, preparation method thereof, and imaging device

Abstract

The present invention discloses a combined imaging detector module, a preparation method thereof, and an imaging device. The combined imaging detector module includes a plurality of layers of scintillation crystal arrays with the same peripheral dimensions, as well as a first photodetector array and a second photodetector array. Among them, the crystal pixel size of each layer of scintillation crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the ray exit end. The first photodetector array is coupled to the scintillation crystal array at the ray incident end, and the second photodetector array is coupled to the scintillation crystal array at the ray exit end. A reflective layer is applied to the outermost layer of the plurality of layers of scintillation crystal arrays; the first photodetector array is used to detect low-energy rays, and the first photodetector array and the second photodetector array are used to detect high-energy rays. The above-mentioned combined imaging detector module can detect high- and low-energy rays simultaneously.

Description

Technical Field

[0001] The present invention relates to the field of electronic imaging technology, and in particular to a combined imaging detector module, a preparation method of the combined imaging detector module, and an imaging device. Background Art

[0002] At present, single photon emission computed tomography (SPECT), positron emission tomography (PET), and computed tomography (CT) are commonly used technologies for imaging the human body or its parts. Among them, the fusion imaging of PET devices and CT devices has become one of the main bases for doctors to diagnose diseases. At the same time, in some application scenarios, there is also a need for the simultaneous imaging of PET devices and SPECT devices to utilize the imaging characteristics of both and observe the development process of diseases.

[0003] However, different types of imaging devices can only detect rays of different energies (including high-energy rays and low-energy rays). Therefore, the three imaging devices need to use different detectors, gantries, electronic readout devices, data acquisition devices, and data processing mechanisms respectively, which greatly increases the structural complexity and manufacturing cost of the fusion imaging device. Moreover, when different types of imaging devices perform fusion imaging, alignment of the imaging intervals is also required, which further increases the difficulty of fusion imaging of different imaging devices. Summary of the Invention

[0004] In view of this, the present application provides a combined imaging detector module, a preparation method thereof, and an imaging device, mainly aiming to solve the technical problem that the imaging device for detecting rays of multiple energies has a complex structure and high manufacturing cost.

[0005] According to the first aspect of the present invention, a combined imaging detector module is provided. The combined imaging detector module includes a plurality of layers of scintillation crystal arrays with the same outer dimensions, as well as a first photodetector array and a second photodetector array. Among them,

[0006] the crystal pixel size of each layer of scintillation crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the ray exit end. The first photodetector array is coupled to the scintillation crystal array at the ray incident end, and the second photodetector array is coupled to the scintillation crystal array at the ray exit end. A reflective layer is applied to the outermost layer of the plurality of layers of scintillation crystal arrays; wherein, the first photodetector array is used to detect low-energy rays, and the first photodetector array and the second photodetector array are used to jointly detect high-energy rays.

[0007] According to a second aspect of the present invention, there is provided a method for manufacturing a combined imaging detector module, which is used to manufacture the combined imaging detector module described in any one of the above embodiments. The method includes:

[0008] Select scintillator crystal arrays with multiple crystal pixel sizes, wherein the outer dimensions of each scintillator crystal array are the same;

[0009] Stack multiple scintillator crystal arrays in ascending order of crystal pixel size, and perform coupling processing between the multiple scintillator crystal arrays through optical glue to form a multi-layer scintillator crystal array;

[0010] Couple a set of photodetector arrays to both ends of the multi-layer scintillator crystal array respectively, and apply a reflective layer to the outermost layer of the multi-layer scintillator crystal array to form a combined imaging detector module.

[0011] According to a third aspect of the present invention, there is provided an imaging device, which includes the combined imaging detector module described in any one of the above embodiments.

[0012] A combined imaging detector module, a manufacturing method thereof, and an imaging device provided by the present invention can jointly detect high-energy rays and low-energy rays with different spatial resolution requirements by arranging multiple scintillator crystal arrays with the same outer dimensions in ascending order of crystal pixel size, setting the number of crystal pixels of each layer of scintillator crystal array to an integer multiple of the number of crystal pixels of the scintillator crystal array at the ray exit end, and coupling a set of photodetector arrays capable of simultaneously detecting rays with different energies to both ends of the multi-layer scintillator crystal array, avoiding the problems of complex mechanical structure, high manufacturing cost, and large image registration difficulty caused by using multiple independent imaging systems. In addition, the above combined imaging detector module only needs two groups of photodetection elements to complete the identification of multiple layers of crystals, and the multi-layer scintillator crystal array and the photodetection elements can form an integral array through coupling, effectively increasing the mechanical strength of the detector module and reducing the process complexity and structural complexity of the detection module.

[0013] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features, and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0015] Figure 1 Shows a schematic three-dimensional structure diagram of a multi-modal imaging detector provided in the prior art;

[0016] Figure 2 Shows a schematic cross-sectional structure diagram of a combined imaging detector module provided in an embodiment of the present invention;

[0017] Figure 3 Shows a schematic cross-sectional structure diagram of another combined imaging detector module provided in an embodiment of the present invention;

[0018] Figure 4 Shows a schematic diagram of the scintillation photon transmission path of a combined imaging detector module provided in an embodiment of the present invention;

[0019] Figure 5 Shows a schematic cross-sectional structure diagram of yet another combined imaging detector module provided in an embodiment of the present invention;

[0020] Figure 6 Shows a schematic cross-sectional structure diagram of yet another combined imaging detector module provided in an embodiment of the present invention;

[0021] Figure 7 Shows a schematic flow diagram of a method for preparing a combined imaging detector module provided in an embodiment of the present invention;

[0022] Figure 8 Shows a schematic flow diagram of another method for preparing a combined imaging detector module provided in an embodiment of the present invention;

[0023] Figure 9a Shows a schematic simulation diagram of the depth of interaction inside the crystal when a combined imaging detector module provided in an embodiment of the present invention detects low-energy rays;

[0024] Figure 9b Shows a schematic simulation diagram of the low-energy ray positioning map identified by the photodetector array at the ray incident end of a combined imaging detector module provided in an embodiment of the present invention;

[0025] Figure 9c Shows a schematic simulation diagram of the depth of interaction inside the crystal when a combined imaging detector module provided in an embodiment of the present invention detects high-energy rays;

[0026] Figure 9d Shows a schematic simulation diagram of the light collection ratio of the photodetector arrays at the ray incident end and the ray exit end of a combined imaging detector module provided in an embodiment of the present invention;

[0027] Figure 9eIt shows a simulation schematic diagram of the positioning map of high-energy rays by the photodetector array at the ray exit end of a combined imaging detector module provided by an embodiment of the present invention;

[0028] Figure 9f It shows a simulation schematic diagram of the positioning map of high-energy rays by the photodetector array at the ray incident end of a combined imaging detector module provided by an embodiment of the present invention;

[0029] Figure 10a It shows a simulation schematic diagram of the light collection ratio of the photodetector arrays at the ray incident end and the ray exit end of another combined imaging detector module provided by an embodiment of the present invention;

[0030] Figure 10b It shows a simulation schematic diagram of the positioning map of high-energy rays by the photodetector array at the ray exit end of another combined imaging detector module provided by an embodiment of the present invention;

[0031] Figure 10c It shows a simulation schematic diagram of the positioning map of high-energy rays by the photodetector array at the ray incident end of another combined imaging detector module provided by an embodiment of the present invention. Detailed implementation manners

[0032] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0033] Currently, in the field of electronic imaging technology, for rays of different energies, different imaging devices (such as PET devices, CT devices, and SPECT devices) need to be used for detection. For different imaging devices, different detectors, electronic readout devices, and data acquisition devices need to be provided, which greatly increases the cost and structural complexity of fusion imaging with multiple imaging devices. At the same time, in order to obtain the image fusion results and combined analysis of different imaging devices, it is also necessary to keep the imaging intervals between multiple imaging devices consistent, which poses higher requirements for bed positioning and patient body position maintenance.

[0034] For example, when performing fusion imaging of PET and CT, two completely independent gantries and detectors are required, which requires a rather complex mechanical structure. At the same time, the two devices also require two completely independent imaging devices, which further increases the cost of fusion imaging. In addition, in order to obtain the fusion image results of PET and CT, the patient must be moved relative to the two gantries, which requires precise positioning and the patient's body position to be kept consistent, which further increases the difficulty of PET-CT fusion imaging.

[0035] In view of the above problems, a design concept of a multimodal imaging detector has emerged at present. For example, Figure 1 As shown, the multimodal imaging detector is stacked with multiple detector modules, which can independently detect high-energy rays and low-energy rays respectively. Among them, multiple detector modules can share a set of racks. Although such an imaging detector seemingly can detect two kinds of ray signals, however, this kind of imaging detector needs to independently detect the two kinds of ray signals, which is not convenient to use. At the same time, there are multiple groups of photoelectric detection elements between the detector modules of different layers, which will cause more ray attenuation and scattering, thus affecting the imaging quality. In addition, more mechanical structures and photoelectric detection elements need to be set during the preparation of this imaging detector, making it difficult for the imaging detector to form a whole, which further increases the manufacturing cost, process complexity and mechanical mechanism complexity of the imaging detector.

[0036] Based on this, in view of the problems of complex structure, high manufacturing cost and difficult image registration of the imaging detector for detecting rays of multiple energies in the prior art, this embodiment provides a combined imaging detector module, such as Figure 2 As shown, the combined imaging detector module includes a plurality of layers of scintillator crystal arrays with the same outer dimensions and a first photodetector array and a second photodetector array coupled to both ends of the plurality of layers of scintillator crystal arrays. Among them, the crystal pixel size of each layer of scintillator crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of scintillator crystal array is an integer multiple of the number of crystal pixels of the scintillator crystal array at the ray exit end. Further, the first photodetector array is coupled to the scintillator crystal array at the ray incident end, the second photodetector array is coupled to the scintillator crystal array at the ray exit end, and a reflective layer is applied to the outermost layer of the plurality of layers of scintillator crystal arrays. In this embodiment, the first photodetector array can be used to detect low-energy rays, and the first photodetector array and the second photodetector array can also be used to jointly detect high-energy rays.

[0037] Specifically, the above-mentioned multi-layer scintillation crystal array can be coupled by optical glue to form an integral array. Among them, the crystal pixel size of the scintillation crystal close to the ray incident direction is relatively small and can be used to detect low-energy rays, such as the X-rays of a CT tube. Given that the detection results of low-energy rays require high spatial resolution and accuracy, therefore, the crystal pixel size of the scintillation crystal close to the ray incident end can be as small as possible to improve the spatial resolution of low-energy rays. Correspondingly, the crystal pixel size of the scintillation crystal far from the ray exit direction is relatively large and can be used to detect high-energy rays, such as gamma rays. Given that high-energy rays have strong penetration ability and require a longer crystal thickness, therefore, in order to better detect the Compton scattering effect in the crystal and accurately determine the incident position of the ray, the size of the scintillation crystal close to the ray exit end can be set slightly longer, or the scintillation crystal close to the ray exit end can be set as multiple layers.

[0038] Furthermore, in the above-mentioned multi-layer scintillation crystal array, the number of crystal pixels in each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels in the outermost scintillation crystal array (i.e., the scintillation crystal array at the ray exit end). For example, the detector module consists of three layers of scintillation crystal arrays, and the outermost scintillation crystal array consists of A*A crystals of B(mm)*B(mm). Then the number of crystal pixels in the middle layer scintillation crystal array is an integer multiple N of A, and the number of pixels in the bottom layer crystal array (i.e., the scintillation crystal array at the ray incident end) is M times that of A, where M > N. The pixel sizes of the crystals in the two layers are B / N and B / M respectively. This detector design can ensure that there is no crosstalk between the finally formed A*A light paths, reduce the photon loss caused by cross-connection, and thus can form a clearer and more separable position map.

[0039] In this embodiment, when detecting high-energy rays, all scintillation crystal arrays and photodetector arrays can be involved, including the front-end scintillation crystal array for detecting low-energy rays and the first photodetector array. Further, a group of photodetector arrays are respectively coupled at both ends (i.e., the ray incident end and the ray exit end) of the multi-layer scintillation crystal array, where the sizes of the photodetector arrays are respectively adapted to both ends of the multi-layer scintillation crystal array. A reflective layer is also applied to the outermost layer of the multi-layer crystal array. When applying the reflective layer, various methods can be used, such as using a reflective material to encapsulate the periphery of the multi-layer scintillation crystal array and the photodetector array as a whole.

[0040] In this embodiment, the cross-sectional view of the above-mentioned combined imaging detector module can be referred to Figure 2 and Figure 3 as shown. Among them, Figure 2 provides a combined imaging detector module including two layers of scintillation crystal arrays and two groups of photodetector arrays.Figure 3 A combined imaging detector module is provided, which includes a three-layer scintillation crystal array and two groups of photodetector arrays. Among them, Figure 2 The two-layer scintillation crystal arrays of the combined imaging detector module shown are the scintillation crystal array 1 and the scintillation crystal array 2 respectively; Figure 3 The three-layer scintillation crystal arrays of the combined imaging detector module shown are the scintillation crystal array 1, the scintillation crystal array 2, and the scintillation crystal 3 respectively. The multi-layer scintillation crystal arrays of the above two combined imaging detectors can be coupled through optical glue, and the crystal pixel size of each layer of the scintillation crystal array in the multi-layer scintillation crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the ray exit end.

[0041] Furthermore, Figure 4 A schematic diagram of the simulated scintillation photon transmission path is provided, as shown in Figure 4 When detecting low-energy rays and / or high-energy rays using the combined imaging detector module shown in Figure 3 , whether the rays are deposited on the scintillation crystal array 1 or on the scintillation crystal array 2 and the scintillation crystal 3, the photodetector arrays at both ends of the multi-layer scintillation crystal array can detect the scintillation photons. However, due to the difference in ray segmentation by the scintillation crystal, the transmission paths of photons of different energy rays will be different. Therefore, the obtained positioning information will also be different. In this embodiment, since the combined imaging detector module needs to ensure the optical path connection between the multi-layer scintillation crystal arrays, only two groups of photodetector elements are required to complete the identification of the multi-layer crystals. At the same time, the scintillation crystal array and the photodetector array can be directly coupled using optical glue to form an integral array, instead of, like the multi-modal imaging detector in the prior art, bonding scintillation crystals on both the front and back sides of the photodetector element, nor adding additional mechanical structures to increase the mechanical strength of the detector, and nor adding more detector elements for crystal identification. Therefore, the combined imaging detector module provided in this embodiment can effectively increase the overall mechanical strength of the detector and reduce the manufacturing cost, mechanical structure complexity, and process complexity.

[0042] In the above embodiments, the number of layers and the size of the scintillating crystal array are not limited, and the arrangement positions of the photodetector elements in the photodetector array are not limited, and double-end light collection can be obtained. It should be noted that the length of the scintillating crystals in the scintillating crystal array in this embodiment can be determined according to the material of the crystal and the maximum energy of the rays to be detected. Among them, the materials of the scintillating crystals in each layer of the scintillating crystal array can be the same or different. For example, inorganic scintillating crystals and ceramics can be selected as materials for making scintillating crystals. In addition, before the scintillating crystals are coupled into a scintillating crystal array, the front surface thereof needs to be pretreated. For example, polishing and frosting treatments can be performed, and the specific treatment method can also be selected according to actual needs. Further, the photodetector elements in the photodetector array can be selected according to actual conditions. For example, photomultiplier tubes (PMTs), siPMs or photodiodes can be selected as photodetector elements. In addition, the size of the photodetector elements can also be selected according to the size of the scintillating crystals and the readout design method, and this embodiment does not make specific limitations here.

[0043] The combined imaging detector module provided in this embodiment arranges multiple layers of scintillating crystal arrays with the same outer dimensions in ascending order of crystal pixel size, sets the number of crystal pixels in each layer of the scintillating crystal array to an integer multiple of the number of crystal pixels in the scintillating crystal array at the ray exit end, and couples a group of photodetector arrays capable of simultaneously detecting different energy rays at both ends of the multiple layers of scintillating crystal arrays, so as to realize the co-detection of high-energy rays and low-energy rays with different spatial resolution requirements, and avoid the problems of complex mechanical structure, high manufacturing cost and large image registration difficulty caused by using multiple independent imaging systems. In addition, the above combined imaging detector module only needs two groups of photodetector elements to complete the identification of multiple layers of crystals, and the multiple layers of scintillating crystal arrays and photodetector elements can form an integral array through a coupling method, effectively increasing the mechanical strength of the detector module and reducing the process complexity and structural complexity of the detection module.

[0044] In one embodiment, the above combined imaging detector module can be used to detect the incident position and energy value of low-energy rays based on the photon number distribution received by the first photodetector array; and / or to detect the incident position, energy value, and interaction depth of high-energy rays based on the ratio and sum of the photon number distributions received by the first photodetector array and the second photodetector array. Herein, the photon number distribution, also known as the ray positioning map, refers to the distribution of the number of photons received by each photodetection element in the photodetector array across the entire photodetector array. In this embodiment, when using the combined imaging detector module to detect low-energy rays, the incident position of the low-energy rays can be calculated based on the photon number distribution received by the first photodetector array, and the energy value of the low-energy rays can be calculated based on the sum of the numbers of photons received by the first photodetector array. Further, when using the combined imaging detector module to detect high-energy rays, the incident position of the high-energy rays can be calculated based on the photon number distributions received by the first photodetector array and the second photodetector array, then the energy value of the high-energy rays can be calculated based on the sum of the numbers of photons received by both photodetector arrays, and finally, the interaction depth of the high-energy rays can be obtained based on the ratio of the numbers of photons received by both photodetector arrays and the relationship curve between the photon number ratio and the interaction depth.

[0045] Refer to Figure 2 and Figure 3As shown in the combined imaging detector module in [description], in this embodiment, when detecting low-energy rays, only the first photodetector array coupled to the ray incident end can be used for detection. At this time, low-energy rays are basically deposited in the scintillation crystal array with a relatively small crystal pixel size. The number of photons collected by the first photodetector array will be much larger than that of the second photodetector array. Therefore, the second photodetector array can be not used for detection, and only the number of photons received by the first photodetector array can be relied on for position localization and energy collection. When detecting high-energy rays, the first photodetector array coupled to the ray incident end and the second photodetector array coupled to the ray exit end can be used for detection simultaneously. Thus, by the light collection ratio of the two-end photodetector arrays (rays are deposited at different crystal depths, and the number of photons collected by the two-end photodetector elements is different), the interaction depth of the rays in the detector can be judged, which will effectively correct the reconstruction deviation caused by the interaction depth of high-energy rays. In addition, if Compton scattering occurs in the crystal, multi-layer crystals can also be used to accurately locate the incident position of the rays. Among them, Compton scattering refers to the phenomenon that when an electromagnetic wave is scattered by a charged particle, the wavelength increases. In this embodiment, by coupling scintillation crystal arrays with different crystal pixel sizes through optical glue and using different readout methods to detect high-energy rays and low-energy rays respectively, co-detection of low-energy rays and high-energy rays can be achieved. While saving costs, it can also solve the problem of reconstruction deviation caused by the inability to judge the interaction depth of high-energy rays and the problem of inaccurate positioning of the incident position caused by the Compton scattering effect.

[0046] In one embodiment, the number of layers of the multi-layer scintillation crystal array in the above imaging detector module can be two or three. Among them, each layer of the multi-layer scintillation crystal array can be coupled through optical glue, and the crystals in the multi-layer scintillation crystal array can be coupled through a reflective layer. In this embodiment, the number of layers of the multi-layer scintillation crystal array can be set to two or three. It can be understood that too many crystal layers will lead to an overly complex photon transmission path. In addition, it will also lead to an increase in photon loss during transmission, resulting in deterioration of the detector properties (energy resolution and time resolution) during high-energy detection.

[0047] In other embodiments, the scintillation crystal arrays at the ray incident end can also be coupled through optical glue between the crystals, and one or two layers of scintillation crystal arrays near the ray exit end can be coupled through any one of a reflective layer, optical glue, and air. It can be understood that the scintillation crystal arrays near the ray incident end are mainly used to detect low-energy rays. Therefore, in order to ensure the accuracy of the counting rate and spatial resolution of low-energy rays, they can be coupled through a reflective material; while the scintillation crystal arrays near the ray exit end are mainly used to detect high-energy rays, and high-energy rays do not have high requirements for the counting rate and spatial resolution. Therefore, the selectable coupling methods are relatively extensive. For example, any one of reflective layer coupling, optical glue coupling, and air coupling can be selected for coupling.

[0048] In the above embodiments, taking Figure 2 and Figure 3 the combined imaging detector module shown as an example, Figure 2 the scintillation crystal array of the combined imaging detector module shown has only two layers. Therefore, the crystals between the crystals of the scintillation crystal array 1 can be coupled through a reflective layer, and the crystals between the crystals of the scintillation crystal array 2 can be coupled through any one of a reflective layer, optical glue, and air. Further, Figure 3 the scintillation crystal array of the combined imaging detector module shown has three layers. Therefore, the crystals between the crystals of the scintillation crystal array 1 can be coupled through a reflective layer, and the crystals between the crystals of the scintillation crystal array 2 and the scintillation crystal array 3 can be coupled through any one of a reflective layer, optical glue, and air. In this embodiment, by setting different coupling methods between the crystals of the scintillation crystal arrays with different crystal pixel sizes, the combined imaging detector module can take into account the spatial resolution and counting rate required for detecting different energy rays when detecting low-energy rays and high-energy rays, thereby improving the detection accuracy of the combined imaging detector module and reducing the process complexity.

[0049] In one embodiment, each photodetector element of the first photodetector array of the imaging detector module is coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end; each photodetector element of the second photodetector array is coupled to the front surface or side surface of each crystal pixel of the scintillation crystal array at the ray exit end. In this embodiment, photodetector elements need to be bonded at both the ray incident end and the ray exit end, and each photodetector element of the first photodetector array needs to be coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end. In this way, the attenuation of the rays caused by the photodetector elements at the ray incident end can be reduced, thereby avoiding artifacts in the CT image or causing calculation errors. For example, referring to Figures 2-3As shown, each photodetector element of the first photodetector array can be coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end, and each photodetector element of the second photodetector array can be coupled to the front surface of each crystal pixel of the scintillation crystal array at the ray exit end. Refer to Figures 5-6 As shown, each photodetector element of the first photodetector array and the second photodetector array can be coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end. It can be understood that Figures 2-3 and Figures 5-6 only show several schemes for the position setting of the photodetector elements, and other expandable schemes will not be elaborated. In this embodiment, by bonding the photodetector elements at different positions of the crystal pixels at the ray incident end and the ray exit end, the attenuation of the rays can be effectively reduced, thereby improving the detection performance of the combined imaging detector.

[0050] In one embodiment, each photodetector element coupled to the side surface of the crystal pixel of the scintillation crystal array corresponds to one crystal pixel of the scintillation crystal array, and the length of the photodetector element coupled to the side surface of the crystal pixel of the scintillation crystal array is less than the length of the crystal pixel of the scintillation crystal array. In this embodiment, when the photodetector element is bonded to the side surface of the crystal pixel, each crystal pixel of the scintillation crystal array needs to bond a photodetector element. Therefore, the photodetector elements bonded to the side surface of the crystal pixel are in one-to-one correspondence with the number of crystals at the bonding end (ray incident end and / or ray exit end). In addition, refer to Figure 5 and Figure 6 , the length of the photodetector element bonded to the side surface of the crystal pixel should be less than or equal to the length of the crystal pixel at the ray incident end and / or the ray exit end, so that the photodetector element can realize the photon collection function at the ray incident end and the ray exit end.

[0051] In one embodiment, each photodetector element coupled to the front surface of the crystal pixel of the scintillation crystal array corresponds to one or more crystal pixels of the scintillation crystal array, and the outer dimensions of the second photodetector array coupled to the front surface of the crystal pixel of the scintillation crystal array are the same as the outer dimensions of the scintillation crystal array. In this embodiment, the number of crystal pixels at the bonding end (i.e., the ray exit end) corresponding to the photodetector element coupled to the front surface of the crystal pixel can be one-to-one or one-to-many, which depends on the signal readout method of the photodetector element and the coupling method between the crystals at both ends. For example, when the signal readout method of the photodetector element is the individual readout method, the number of crystal pixels at the bonding end corresponding to the photodetector element can be set to one-to-one; when the signal readout method of the photodetector element is the overall readout method, the number of crystal pixels at the bonding end corresponding to the photodetector element can be set to one-to-many, etc. In addition, refer toFigure 2 and Figure 3 , the outer dimensions of the photodetector array composed of photodetector elements bonded to the front surface of the crystal pixels need to be the same as those of the multi-layer crystal array, so as to ensure that the photodetector array and the multi-layer scintillation crystal array can form an integral array, facilitating the application of the radiation layer on the outermost layer of the multi-layer scintillation crystal array.

[0052] In one embodiment, as Figure 7 shown, a method for preparing a combined imaging detector module is provided, which includes the following steps:

[0053] 101. Select scintillation crystal arrays with various crystal pixel sizes, where the outer dimensions of each scintillation crystal array are the same.

[0054] 102. Stack multiple scintillation crystal arrays in ascending order of crystal pixel size, and perform coupling processing between the multiple scintillation crystal arrays through optical glue to form a multi-layer scintillation crystal array.

[0055] 103. Couple a group of photodetector arrays to both ends of the multi-layer scintillation crystal array respectively, and apply a reflective layer on the outermost layer of the multi-layer scintillation crystal array to form a combined imaging detector module.

[0056] In this embodiment, each layer of the scintillation crystal array of the combined imaging detector module is coupled through optical glue. Among them, the crystal pixel size of each layer of the scintillation crystal array in the multi-layer scintillation crystal array increases layer by layer, and the outer dimensions of each layer of the scintillation crystal array are the same. In addition, a group of photodetector arrays are respectively coupled to both ends of the multi-layer scintillation crystal array, and a reflective layer is also applied on the outermost layer of the multi-layer scintillation crystal array. In this embodiment, the end with a relatively small crystal pixel size in the combined imaging detector module can be set at the ray incident end of the imaging device, and the end with a relatively large crystal pixel size can be set at the ray exit end of the imaging device, so that the rays emitted by the imaging device can form an optical path in the multi-layer scintillation crystal array, and the two groups of photodetector arrays coupled at the ray incident end and the ray exit end can jointly detect the high-energy rays and / or low-energy rays emitted by the imaging device.

[0057] Further, in the above multi-layer scintillation crystal array, the number of crystal pixels in each layer of the scintillation crystal array can be an integer multiple of the number of crystal pixels in the outermost scintillation crystal array (i.e., the scintillation crystal array at the ray exit end). For example, the detector module can be composed of three layers of scintillation crystal arrays, and the outermost scintillation crystal array is composed of A*A crystals of B(mm)*B(mm). Then the number of crystal pixels in the middle layer scintillation crystal array is an integer multiple N of A, and the number of pixels in the bottom layer crystal array (i.e., the scintillation crystal array at the ray incident end) is M times that of A, where M > N. The pixel sizes of the crystals in the two layers are B / N and B / M respectively. This detector design can ensure that there is no crosstalk between the finally formed A*A light paths, reduce the photon loss caused by cross-connection, and thus can form a clearer and more separable position map.

[0058] In this embodiment, the cross-sectional view of the finally formed combined imaging detector module can be referred to Figure 2 and Figure 3 as shown. Among them, Figure 2 provides a combined imaging detector module including two layers of scintillation crystal arrays and two groups of photodetector arrays, Figure 3 provides a combined imaging detector module including three layers of scintillation crystal arrays and two groups of photodetector arrays. Among them, Figure 2 the two layers of scintillation crystal arrays of the combined imaging detector module shown are respectively scintillation crystal array 1 and scintillation crystal array 2; Figure 3 the three layers of scintillation crystal arrays of the combined imaging detector module shown are respectively scintillation crystal array 1, scintillation crystal array 2, and scintillation crystal 3. The multi-layer scintillation crystal arrays of the above two combined imaging detectors can be coupled by optical glue, and the crystal pixel sizes of each layer of the scintillation crystal arrays in the multi-layer scintillation crystal arrays increase layer by layer, and the number of crystal pixels in each layer of the scintillation crystal arrays is an integer multiple of the number of crystal pixels in the scintillation crystal array with the largest crystal pixel size.

[0059] Further, Figure 4 provides a schematic diagram of the simulated scintillation photon transmission path, as Figure 4 shown, in the use of such as Figure 3When the combined imaging detector module shown is used to detect low-energy rays and / or high-energy rays, regardless of whether the rays are deposited on the scintillator crystal array 1 or on the scintillator crystal arrays 2 and 3, the photodetector arrays at both ends of the multi-layer scintillator crystal array can detect scintillation photons. However, due to the differences in the ray segmentation of the scintillator crystals, the transmission paths of photons of different energy rays will be different. Therefore, the obtained positioning information will also be different. In this embodiment, since the combined imaging detector module needs to ensure the optical path connection between the multi-layer scintillator crystal arrays, only two groups of photodetector elements are required to complete the identification of the multi-layer crystals. At the same time, both the scintillator crystal array and the photodetector array can be directly coupled with optical glue to form an integral array, instead of bonding scintillator crystals on both the front and back sides of the photodetector elements as in the multi-modal imaging detectors in the prior art, nor adding additional mechanical structures to increase the mechanical strength of the detector, and no more detector elements are needed for crystal identification. Therefore, the combined imaging detector module provided in this embodiment can effectively increase the overall mechanical strength of the detector and reduce the manufacturing cost, mechanical structure complexity, and process complexity.

[0060] In the above embodiment, the number of layers and the size of the scintillator crystal array are not limited, and the placement positions of the photodetector elements in the photodetector array are not limited, as long as double-sided light collection can be obtained. It should be noted that the length of the scintillator crystals in the scintillator crystal array in this embodiment can be determined according to the material of the crystal and the maximum energy of the rays to be detected. Among them, the materials of the scintillator crystals in each layer of the scintillator crystal array can be the same or different. For example, inorganic scintillator crystals and ceramic scintillators can be selected as materials for making the scintillator crystals. In addition, before the scintillator crystals are coupled into a scintillator crystal array, their front surfaces need to be pretreated. For example, polishing and frosting treatments can be performed, and the specific treatment methods can also be selected according to actual needs. Further, the photodetector elements in the photodetector array can be selected according to actual situations. For example, photomultiplier tubes (PMTs), siPMs, or photodiodes can be selected as photodetector elements. In addition, the size of the photodetector elements can also be selected according to the size of the scintillator crystals and the readout design method. This embodiment does not make specific limitations here.

[0061] The preparation method of the combined imaging detector module provided by this embodiment can produce an imaging detector module capable of jointly detecting high-energy rays and low-energy rays with different spatial resolution requirements by arranging and stacking multiple layers of crystal pixel sizes in ascending order, coupling multiple layers of scintillation crystal arrays into a crystal array with a common optical path through optical glue, and coupling a group of photodetector arrays to both ends of the crystal array and applying a reflective layer, thereby avoiding the problems of complex mechanical structure, high manufacturing cost, and great difficulty in image registration caused by using multiple independent imaging systems. In addition, the preparation method of the above combined imaging detector module couples multiple layers of scintillation crystal arrays and photodetection elements into an integral array through optical glue, which can reduce the process complexity and structural complexity of the detection module and increase the mechanical strength of the detector module.

[0062] In one embodiment, as Figure 8 shown, before step 101, the preparation method of the above combined imaging detector module further includes the following steps: First, select crystal pixels of multiple pixel sizes, and perform pre-treatment on the front surface of each crystal pixel, such as frosting or polishing, etc., and then perform coupling treatment between the crystal pixels of each pixel size to form scintillation crystal arrays of multiple crystal pixel sizes, where the outer dimensions of each scintillation crystal array are the same. In this embodiment, scintillation crystals of the same crystal pixel size need to be coupled into a scintillation crystal array, and the outer dimensions of the scintillation crystal arrays of all types of crystal pixel sizes are the same. Among them, the scintillation crystals can be coupled through a reflective layer. In other embodiments, the crystals between the scintillation crystal arrays at the ray incident end can also be coupled through optical glue, and one or two layers of scintillation crystal arrays near the ray exit end can be coupled through any one of a reflective layer, optical glue, and air. It can be understood that the scintillation crystal array with a relatively small crystal pixel size is mainly used to detect low-energy rays. Therefore, in order to ensure the counting rate and the accuracy of the spatial resolution of low-energy rays, coupling can be performed through a reflective material; while the scintillation crystal array with a relatively large crystal pixel size is mainly used to detect high-energy rays. High-energy rays do not have very high requirements for the counting rate and spatial resolution, so the selectable coupling methods are relatively extensive, such as any one of reflective layer coupling, optical glue coupling, and air coupling can be selected for coupling. In addition, before the scintillation crystals are coupled into a scintillation crystal array, their front surfaces can be pre-treated first, for example, polishing and frosting treatment, etc. It can be understood that the pre-treatment method of the scintillation crystals can be selected according to actual needs, and this embodiment does not make specific limitations here.

[0063] In one embodiment, the above step 103 can be implemented through the following steps: Bond a set of photodetector arrays on the front surface or side surface of each crystal pixel at both ends of the multi-layer scintillation crystal array, and then use a reflective material to encapsulate the periphery of the multi-layer scintillation crystal array. In this embodiment, the photodetector array includes a plurality of photodetection elements, where each photodetection element can be bonded to the front surface or side surface of each crystal pixel at both ends of the multi-layer scintillation crystal array through optical glue. In this embodiment, each photodetection element of the photodetector array at the end with the smallest crystal pixel size can be coupled to the side surface of each crystal pixel of the scintillation crystal array; each photodetection element of the photodetector array at the end with the largest crystal pixel size can be coupled to the front surface or side surface of each crystal pixel of the scintillation crystal array. For example, referring to Figures 2-3 as shown, each photodetection element of the first photodetector array is coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end, and each photodetection element of the second photodetector array is coupled to the front surface of each crystal pixel of the scintillation crystal array at the ray exit end. Referring to Figures 5-6 as shown, each photodetection element of the first photodetector array and the second photodetector array are both coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end. It can be understood that Figures 2-3 and Figures 5-6 only show several schemes for the position setting of the photodetection elements, and other expandable schemes will not be elaborated. In this embodiment, by bonding the photodetection elements at different positions at both ends of the multi-layer scintillation crystal array, the attenuation of the rays can be reduced, thereby improving the detection performance of the combined imaging detector.

[0064] In the above embodiment, each photodetection element coupled to the side surface of the crystal pixel of the scintillation crystal array corresponds to one crystal pixel of the scintillation crystal array, and the length of the photodetection element coupled to the side surface of the crystal pixel of the scintillation crystal array is less than the length of the crystal pixel of the scintillation crystal array. In this embodiment, when the photodetection element is bonded to the side surface of the crystal pixel, each crystal pixel of the scintillation crystal array needs to bond a photodetection element. Therefore, the photodetection element bonded to the side surface of the crystal pixel is in a one-to-one correspondence with the number of crystals at the bonding end (ray incident end and / or ray exit end). In addition, referring to Figure 5 and Figure 6 , the length of the photodetection element bonded to the side surface of the crystal pixel is less than the length of the crystal pixel at the ray incident end and / or ray exit end, so that the photodetection element can realize the photon collection function at the ray incident end and the ray exit end.

[0065] In the above embodiments, each photodetector element coupled to the front surface of the crystal pixels of the scintillation crystal array corresponds to one or more crystal pixels of the scintillation crystal array, and the outer dimensions of the second photodetector array coupled to the front surface of the crystal pixels of the scintillation crystal array are the same as the outer dimensions of the scintillation crystal array. In this embodiment, the number of crystals at the end where the bonding method is located (i.e., the radiation exit end) corresponding to the photodetector element coupled to the front surface of the crystal pixel can be one-to-one or one-to-many, depending on the signal readout method of the photodetector element and the coupling method between the crystals at both ends. For example, when the signal readout method of the photodetector element is the individual readout method, the number of crystals at the end where the bonding method is located corresponding to the photodetector element can be set to one-to-one; when the signal readout method of the photodetector element is the overall readout method, the number of crystals at the end where the bonding method is located corresponding to the photodetector element can be set to one-to-many, etc. In addition, referring to Figure 2 and Figure 3 , the outer dimensions of the photodetector array composed of the photodetector elements bonded to the front surface of the crystal pixels need to be the same as the outer dimensions of the multi-layer crystal array, so as to ensure that the photodetector array can form an array as a whole with the multi-layer scintillation crystal array, facilitating the application of the radiation layer on the outermost layer of the multi-layer scintillation crystal array.

[0066] In one embodiment, an imaging device is further provided. The imaging device includes the combined imaging detector module described in any one of the above embodiments. The combined imaging detector module includes a multi-layer scintillation crystal array with the same outer dimensions and a first photodetector array and a second photodetector array coupled to both ends of the multi-layer scintillation crystal array. Among them, the crystal pixel size of each layer of the scintillation crystal array increases layer by layer along the radiation incident direction, and the number of crystal pixels of each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the radiation exit end. Further, the first photodetector array is coupled to the scintillation crystal array at the radiation incident end, the second photodetector array is coupled to the scintillation crystal array at the radiation exit end, and a reflection layer is applied to the outermost layer of the multi-layer scintillation crystal array. In this embodiment, the first photodetector array can be used to detect low-energy radiation, and the first photodetector array and the second photodetector array can also be used to jointly detect high-energy radiation.

[0067] Specifically, the above multi-layer scintillation crystal array can be coupled by optical glue to form a whole detector array. Among them, the crystal pixel size of the scintillation crystal close to the ray incident direction is relatively small and can be used to detect low-energy rays, such as detecting the X-rays of a CT tube. In view of the fact that the detection results of low-energy rays require high spatial resolution and accuracy, therefore, the crystal pixel size of the scintillation crystal close to the ray incident end can be as small as possible to improve the spatial resolution of low-energy rays. Correspondingly, the crystal pixel size of the scintillation crystal far from the ray incident direction is relatively large and can be used to detect high-energy rays, such as detecting gamma rays. In view of the strong penetration ability of high-energy rays, a longer crystal thickness is required. Therefore, in order to better detect the Compton scattering effect in the crystal and accurately judge the incident position of the ray, the size of the scintillation crystal close to the ray exit end can be set slightly longer, or the scintillation crystal close to the ray exit end can be set as multiple layers.

[0068] Further, in the above multi-layer scintillation crystal array, the number of crystal pixels in each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels in the outermost scintillation crystal array (i.e., the scintillation crystal array at the ray exit end). For example, the detector module is composed of three layers of scintillation crystal arrays, and the outermost scintillation crystal array is composed of A*A crystals of B(mm)*B(mm). Then the number of crystal pixels in the middle layer scintillation crystal array is an integer multiple N of A, and the pixels of the bottom layer crystal array (i.e., the scintillation crystal array at the ray incident end) are M times of A, where M > N. The pixel sizes of the crystals in the two layers are B / N and B / M respectively. This kind of detector design can ensure that there is no crosstalk between the finally formed A*A light paths, reduce the photon loss caused by cross-connection, and thus can form a clearer and more separable position map.

[0069] In this embodiment, when detecting high-energy rays, all scintillation crystals and photodetectors can be involved, including the scintillation crystals and photodetectors at the front end for detecting low-energy rays. Further, a group of photodetector arrays are respectively coupled at both ends of the multi-layer scintillation crystal array (i.e., the incident end and the exit end of the ray), where the sizes of the photodetector arrays can be respectively adapted to both ends of the multi-layer scintillation crystal array. A reflective layer is also applied to the outermost layer of the multi-layer crystal array. When applying the reflective layer, various methods can be used, such as using a reflective material to encapsulate the periphery of the multi-layer scintillation crystal array as a whole, etc.

[0070] In this embodiment, the cross-sectional view of the above combined imaging detector module can be referred to Figure 2 and Figure 3 as shown. Among them, Figure 2 provides a combined imaging detector module including two layers of scintillation crystal arrays and two groups of photodetector arrays. Figure 3A combined imaging detector module including a three-layer scintillation crystal array and two groups of photodetector arrays is provided. Among them, Figure 2 The two-layer scintillation crystal arrays of the combined imaging detector module shown are the scintillation crystal array 1 and the scintillation crystal array 2 respectively; Figure 3 The three-layer scintillation crystal arrays of the combined imaging detector module shown are the scintillation crystal array 1, the scintillation crystal array 2, and the scintillation crystal 3 respectively. The multi-layer scintillation crystal arrays of the above two combined imaging detectors can be coupled through optical glue, and the crystal pixel size of each layer of the scintillation crystal array in the multi-layer scintillation crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the ray exit end.

[0071] Furthermore, Figure 4 A schematic diagram of the simulated scintillation photon transmission path is provided. As shown in Figure 4 When using the combined imaging detector module shown in Figure 3 to detect low-energy rays and / or high-energy rays, whether the rays are deposited on the scintillation crystal array 1 or on the scintillation crystal array 2 and the scintillation crystal 3, the photodetector arrays at both ends of the multi-layer scintillation crystal array can detect the scintillation photons. However, due to the difference in ray segmentation by the scintillation crystal, the transmission paths of photons of different energy rays will be different. Therefore, the obtained positioning information will also be different. In this embodiment, since the combined imaging detector module needs to ensure the optical path connection between the multi-layer scintillation crystal arrays, only two groups of photodetector elements are required to complete the identification of the multi-layer crystals. At the same time, the scintillation crystal array and the photodetector array can be directly coupled with optical glue to form an integral array, instead of, like the multi-modal imaging detector in the prior art, bonding scintillation crystals on both the front and back sides of the photodetector elements, nor adding additional mechanical structures to increase the mechanical strength of the detector, and nor adding more detector elements for crystal identification. Therefore, the combined imaging detector module provided in this embodiment can effectively increase the overall mechanical strength of the detector, and reduce the manufacturing cost, the complexity of the mechanical structure, and the complexity of the process.

[0072] In the above embodiments, the number of layers and the size of the scintillator crystal array are not limited, and the arrangement positions of the photodetector elements in the photodetector array are not limited, and dual-end light collection can be achieved. It should be noted that the length of the scintillator crystals in the scintillator crystal array in this embodiment can be determined according to the material of the crystal and the maximum energy of the rays to be detected. Among them, the materials of the scintillator crystals in each layer of the scintillator crystal array can be the same or different. For example, inorganic scintillator crystals and ceramics can be selected as the materials for making the scintillator crystals. In addition, before the scintillator crystals are coupled into a scintillator crystal array, their front surfaces need to be pretreated. For example, polishing and frosting treatments can be performed, and the specific treatment method can also be selected according to actual requirements. Further, the photodetector elements in the photodetector array can be selected according to actual conditions. For example, photomultiplier tubes (PMTs), siPMs, or photodiodes can be selected as the photodetector elements. In addition, the size of the photodetector elements can also be selected according to the size of the scintillator crystals and the readout design method, and this embodiment does not make specific limitations here.

[0073] The imaging device provided in this embodiment can jointly detect high-energy rays and low-energy rays with different spatial resolution requirements by using a combined imaging detector module, avoiding the problems of complex mechanical structure and high manufacturing cost caused by using multiple independent imaging systems.

[0074] In one embodiment, to specifically illustrate the structural characteristics of the combined imaging detector module and the preparation method of the combined imaging detector module, this embodiment provides a specific example. This example uses 1mm*1mm*5mm LYSO crystals (lutetium yttrium silicate crystals) to form a scintillator crystal array with a small crystal pixel size of 15*15, and is paired with a 15*15 siPM (silicon photomultiplier) array with a size of 1mm*1mm to form a photodetector array at the ray incident end. Then, 3mm*3mm*13mm LYSO crystals are used to form a scintillator crystal array with a large crystal pixel size of 5*5, and are paired with a 3mm*3mm siPM array to form a photodetector array at the ray exit end. Each crystal array internally uses BaSo4 (barium sulfate) for reflective layer coupling. The schematic cross-sectional structure diagrams of the above combined imaging detector are respectively as Figure 2 shown.

[0075] Further, in the above combined imaging detector module, 140keV and 511keV gamma rays are respectively incident vertically. From the simulation results, the 5mm LYSO can intercept almost all 140keV rays. Among them, Figure 9a is a simulation schematic diagram of the interaction depth (deposition depth in the crystal) of low-energy rays (i.e., 140keV rays) inside the crystal.Figure 9b The low-energy ray positioning map (i.e., photon number distribution) identified by the photodetector array at the ray incident end Figure 9c is a simulation schematic diagram of the interaction depth of high-energy rays (i.e., 511 keV rays) inside the crystal. Figure 9d is the photon collection ratio (small sipm / large sipm light collection) of the photodetector arrays at the ray incident end and the ray exit end at different interaction depths. According to the different ratios, the interaction depth of gamma rays can be obtained. Figure 9e and Figure 9f are respectively the positioning maps (i.e., photon number distribution) of the photodetector arrays at the ray exit end and the ray incident end for high-energy rays.

[0076] Referring to the previous example, a combined imaging detector module with a three-layer scintillating crystal array can also be designed. The cross-sectional structure schematic diagram of the combined imaging detector module is as shown in Figure 3 . Among them, the crystal size of the middle layer of the above combined imaging detector module is 1.5 mm * 1.5 mm, and the lengths of the three layers of crystals are all 6 mm. Further, the high-energy ray simulation results of the combined imaging detector module are as shown in Figures 10a-10c . Among them, Figure 10a is the photon collection ratio of the photodetector arrays at both ends, and Figure 10b and Figure 10c are respectively the position identification spectra (i.e., photon number distribution) of the photodetector arrays at the ray exit end and the ray incident end.

[0077] As can be seen from the simulation diagrams of the above two combined imaging detector modules, the combined imaging detector modules proposed in the embodiments of the present application can jointly detect high-energy rays and low-energy rays with different spatial resolution requirements, avoiding the problems of complex mechanical structure, high manufacturing cost, and large image registration difficulty caused by using multiple independent imaging systems. In addition, the above combined imaging detector module only needs two groups of photodetector elements to complete the identification of multiple layers of crystals, and the multiple-layer scintillating crystal array and the photodetector elements can be directly coupled with optical glue and form an integral array, effectively increasing the mechanical strength of the detector module and reducing the process complexity and structural complexity of the detection module.

[0078] Those skilled in the art can understand that the structures of a combined imaging detector module and an imaging device provided in this embodiment do not limit the imaging module and the imaging device, and may include more or fewer components, or combine some components, or have different component arrangements.

[0079] Those skilled in the art can understand that the attached drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the attached drawings are not necessarily essential for implementing the present application. Those skilled in the art can understand that the modules in the devices in the implementation scenario can be distributed in the devices in the implementation scenario according to the description of the implementation scenario, or can be correspondingly changed and located in one or more devices different from this implementation scenario. The modules in the above implementation scenario can be combined into one module, or can be further split into multiple sub-modules.

[0080] The above serial numbers of the present application are only for description and do not represent the advantages or disadvantages of the implementation scenario. The above-disclosed are only several specific implementation scenarios of the present application. However, the present application is not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A combined imaging detector module, characterized in that, The combined imaging detector module includes a plurality of layers of scintillation crystal arrays with the same outer dimensions, as well as a first photodetector array and a second photodetector array. Among them, the crystal pixel size of each layer of the scintillation crystal array increases layer by layer along the ray incident direction, and the number of crystal pixels of each layer of the scintillation crystal array is an integer multiple of the number of crystal pixels of the scintillation crystal array at the ray exit end. The first photodetector array is coupled to the scintillation crystal array at the ray incident end, and the second photodetector array is coupled to the scintillation crystal array at the ray exit end. A reflective layer is applied to the outermost layer of the multiple layers of scintillation crystal arrays; wherein, the first photodetector array is used to detect low-energy rays, and the first photodetector array and the second photodetector array are used to jointly detect high-energy rays; the combined imaging detector module is used to detect the incident position and energy value of the low-energy rays through the photon number distribution received by the first photodetector array; and / or is used to detect the incident position, energy value and interaction depth of the high-energy rays through the ratio and sum of the photon number distribution received by the first photodetector array and the photon number distribution received by the second photodetector array.

2. The combined imaging detector module according to claim 1, wherein The number of layers of the multiple layers of scintillation crystal arrays is two or three. Among them, each layer of the multiple layers of scintillation crystal arrays is coupled by an optical adhesive, and the crystals of the multiple layers of scintillation crystal arrays are coupled by a reflective layer.

3. The combined imaging detector module according to claim 1, characterized in that Each photodetection element of the first photodetector array is coupled to the side surface of each crystal pixel of the scintillation crystal array at the ray incident end; each photodetection element of the second photodetector array is coupled to the front surface or side surface of each crystal pixel of the scintillation crystal array at the ray exit end.

4. The combined imaging detector module according to claim 3, wherein Each photodetection element coupled to the side surface of the crystal pixel of the scintillation crystal array corresponds to a crystal pixel of the scintillation crystal array, and the length of the photodetection element coupled to the side surface of the crystal pixel of the scintillation crystal array is less than or equal to the length of the crystal pixel of the scintillation crystal array.

5. The combined imaging detector module according to claim 3, wherein Each photodetection element coupled to the front surface of the crystal pixel of the scintillation crystal array corresponds to one or more crystal pixels of the scintillation crystal array, and the outer dimensions of the second photodetector array coupled to the front surface of the crystal pixel of the scintillation crystal array are the same as the outer dimensions of the scintillation crystal array.

6. A preparation method of a combined imaging detector module, characterized in that The method is used to prepare the combined imaging detector module according to any one of claims 1 to 5. The method includes: selecting scintillation crystal arrays with multiple crystal pixel sizes, wherein the outer dimensions of each scintillation crystal array are the same; stacking the multiple scintillation crystal arrays in the order of increasing crystal pixel size, and coupling the multiple scintillation crystal arrays by an optical adhesive to form a multiple layer scintillation crystal array; Couple a group of photodetector arrays to both ends of the multi-layer scintillating crystal array respectively, and apply a reflective layer to the outermost layer of the multi-layer scintillating crystal array to form the combined imaging detector module.

7. The method according to claim 6, wherein Before the scintillating crystal array with multiple crystal pixel sizes is selected, the method further includes: Select crystal pixels with multiple pixel sizes, and perform preprocessing on the front surface of each crystal pixel; Perform coupling processing between crystal pixels of each pixel size respectively to form a scintillating crystal array with multiple crystal pixel sizes, wherein the outer dimensions of each scintillating crystal array are the same.

8. The method according to claim 6, characterized in that, The step of coupling a group of photodetector arrays to both ends of the multi-layer scintillating crystal array respectively, and applying a reflective layer to the outermost layer of the multi-layer scintillating crystal array includes: Couple a group of photodetector arrays to the front surface or side surface of each crystal pixel at both ends of the multi-layer scintillating crystal array respectively; Use a reflective material to encapsulate the periphery of the multi-layer scintillating crystal array.

9. An imaging device, characterized in that, The imaging device includes the combined imaging detector module according to any one of claims 1 to 5.

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