Detector microblock and detector block for emission computed tomography

Abstract

The embodiment of the utility model discloses a detector micro block and a detector block for emission computed tomography. The detector microblock may include detector cells arranged side-by-side in a second direction. Each detector cell may include a crystalline element and an array of optical sensors. The crystal elements may be arranged in a row of crystal elements in a second direction and in a column of crystal elements in a first direction perpendicular to the second direction. Each crystal element may include a first end and a second end and extend from the first end to the second end in a third direction perpendicular to the first direction and the second direction. The optical sensor array may include optical sensors arranged in a first direction.

Description

[0001] Cross-references

[0002] The present invention claims the benefit of U.S. Provisional Patent Application No. 63 / 579,949 filed on August 31, 2023 and U.S. Patent Application No. 18 / 617,620 filed on March 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present specification relates to the field of medical technology, and in particular to a detector microblock and a detector block for emission computed tomography (ECT). Background Art

[0004] Spatial resolution is one of the most important performance indicators of ECT detectors. The spatial resolution is usually improved by reducing the crystal size of the crystal elements in the ECT detector. However, reducing the crystal size will lead to an increase in the number of crystal elements in the ECT detector, thereby increasing the complexity of the ECT detector structure and the amount of data for image processing, and reducing the temporal resolution of the ECT detector.

[0005] Therefore, there is an urgent need to provide an ECT detector microblock / detector block and a method for determining the depth of interest (DOI) in an ECT detector, so as to improve the spatial resolution of the ECT detector without increasing the number of crystal elements in the ECT detector or reducing the temporal resolution of the ECT detector, thereby improving the accuracy of ECT imaging. Utility Model Content

[0006] One of the embodiments of the utility model provides a detector microblock for transmitting computed tomography. The detector microblock may include detector units arranged side by side along a second direction. Each detector unit may include a crystal element and an optical sensor array. The crystal elements may be arranged into crystal element rows along the second direction and into crystal element columns along a first direction perpendicular to the second direction. Each crystal element may include a first end and a second end, and extend from the first end to the second end along a third direction perpendicular to the first direction and the second direction. The optical sensor array may include optical sensors arranged along the first direction. In each crystal element row, the first end of the crystal element may be optically coupled with an optical sensor in the optical sensor array, and the second end of the crystal element in each crystal element column may be configured with an optical bridge.

[0007] In some embodiments, for each crystal element column in each detector unit, an optical separator may be configured between each pair of adjacent crystal elements in the crystal element column. The optical separator may extend from the first end of the corresponding pair of adjacent crystal elements but not reach the second end of the corresponding pair of adjacent crystal elements.

[0008] In some embodiments, the second ends of the crystal elements in each crystal element column are integrated into a single piece to serve as an optical bridge.

[0009] In some embodiments, the optical bridge of each crystal element column may include an optical propagation medium disposed between each pair of adjacent crystal elements in the crystal element column. The optical propagation medium may extend from the second ends of the corresponding pair of adjacent crystal elements to the optical separator between the corresponding pair of adjacent crystal elements.

[0010] In some embodiments, for each detector unit, an optical separator may be configured between each pair of adjacent crystal element columns in the detector unit. The optical separator may extend from a first end of a crystal element in a corresponding pair of adjacent crystal element columns to a second end of a crystal element in a corresponding pair of adjacent crystal element columns.

[0011] In some embodiments, for each crystal element column of each detector unit, an optical separator may be configured between each pair of adjacent crystal elements in the crystal element column. The optical separator may extend from the first end of the corresponding pair of adjacent crystal elements to the second end of the corresponding pair of adjacent crystal elements. The optical bridge may include an optical propagation medium, which covers the second ends of the crystal elements in the crystal element column.

[0012] In some embodiments, a second optical bridge may be configured between each pair of adjacent detector units in the detector microblock.

[0013] In some embodiments, an optical separator may be disposed between each pair of adjacent detector units in the detector microblock, and the optical separator may extend from the second end of the crystal element in the corresponding pair of adjacent detector units, but not reach the first end of the crystal element in the corresponding pair of adjacent detector units.

[0014] In some embodiments, for each detector unit, in each crystal element column of the detector unit, two crystal elements may be arranged along a first direction, and in each crystal element row of the detector unit, two crystal elements may be arranged along a second direction.

[0015] In some embodiments, each crystal element may include a long side along the first direction and a short side along the second direction. The length of the long side along the first direction may be greater than the length of the short side along the second direction.

[0016] In some embodiments, a ratio of a length of a long side along the first direction to a length of a short side along the second direction may be greater than 1 and less than 5.

[0017] In some embodiments, the crystal element array and the detector micro-block may have a U-shaped structure or an inverted U-shaped structure, respectively.

[0018] One embodiment of the utility model provides a detector block for transmitting computed tomography, wherein the detector block may include a plurality of the above-mentioned detector micro-blocks, and the plurality of detector micro-blocks may be arranged in a block array.

[0019] In some embodiments, short sides of the crystal elements in the plurality of detector micro-blocks may be parallel to each other.

[0020] In some embodiments, short sides of the crystal elements of one or more first detector micro-blocks in the plurality of detector micro-blocks may be perpendicular to short sides of the crystal elements of one or more second detector micro-blocks in the plurality of detector micro-blocks.

[0021] In some embodiments, each pair of adjacent detector microblocks in the plurality of detector microblocks may include a first detector microblock and a second detector microblock to form a checkerboard structure. Each row of detector microblocks in the detector blocks parallel to a diagonal direction of the block array may have the same orientation, and the orientations of the detector microblocks in adjacent rows parallel to the diagonal direction may be perpendicular to each other.

[0022] In some embodiments, the detector block may include a first sub-block and a second sub-block, each of the first sub-block and the second sub-block may include multiple detector micro-blocks, each detector micro-block of the first sub-block may have a first arrangement, and each detector micro-block of the second sub-block may have a second arrangement, and the second arrangement is different from the first arrangement.

[0023] One of the embodiments of the utility model provides a detector microblock for transmitting computed tomography. The detector microblock may include one or more detector units, each of which includes a crystal element and an optical sensor array. The crystal elements may be arranged into crystal element rows along the second direction and into crystal element columns along a first direction perpendicular to the second direction, and the crystal element columns may be configured as a U-shaped structure or an inverted U-shaped structure. The optical sensor array may include optical sensors arranged along the first direction. In each crystal element row, the crystal element may be optically coupled with an optical sensor in the optical sensor array.

[0024] In some embodiments, the detector unit may further include an optical separator and an optical bridge, and the optical separator and the optical bridge may be disposed in the U-shaped structure or the inverted U-shaped structure of the crystal element column.

[0025] In some embodiments, the detector micro-block may have a U-shaped structure or an inverted U-shaped structure.

[0026] Some additional features of the utility model may be explained in the following description. Some additional features of the utility model will be apparent to those skilled in the art through study of the following description and the corresponding drawings or understanding of the production or operation of the embodiments. The features of the utility model may be realized and obtained by practicing or using various aspects of the methods, means and combinations set forth in the detailed examples discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

[0028] Figure 1 is a schematic diagram of an exemplary imaging system according to some embodiments of the present specification;

[0029] Figure 2 is a schematic diagram of an exemplary crystal group according to some embodiments of the present specification;

[0030] Figure 3A and Figure 3B is a schematic diagram of an exemplary photon gamma interaction occurring in an exemplary crystal group according to some embodiments of the present specification;

[0031] Figure 4A is a schematic diagram of an exemplary crystal group according to some embodiments of the present specification;

[0032] Figure 4B is a schematic diagram of an exemplary crystal group according to some embodiments of the present specification;

[0033] Figure 5A is a schematic diagram of an exemplary detector microblock according to some embodiments of the present specification;

[0034] Figure 5B is a schematic diagram of a rear view of an exemplary detector microblock according to some embodiments of the present specification;

[0035] Figure 5C is a schematic diagram of a right side view of an exemplary detector microblock according to some embodiments of the present specification;

[0036] Figure 5D is a schematic diagram of a top view of an exemplary detector microblock according to some embodiments of the present specification;

[0037] Figure 6A-6Fis a schematic top view of an exemplary detector block according to some embodiments of the present specification;

[0038] Figure 7 is a block diagram of an exemplary processing device according to some embodiments of the present specification;

[0039] Figure 8 is a flow chart of an exemplary process for determining a location of a photon gamma interaction in a detector microblock according to some embodiments of the present specification;

[0040] Fig. 9 is a flowchart of an exemplary process of ECT according to some embodiments of the present specification; and

[0041] Fig.10 is an exemplary reconstructed image shown in some embodiments of the present specification. DETAILED DESCRIPTION

[0042] In order to more clearly illustrate the technical solution of the embodiment of the utility model, the following is a brief introduction to the drawings required for the description of the embodiment. Obviously, the drawings described below are only some examples or embodiments of this specification. For ordinary technicians in this field, this specification can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0043] It should be understood that the "system", "device", "unit" and / or "module" used herein are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

[0044] As shown in this specification and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0045] It is to be understood that although the terms "first", "second", "third", "fourth", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments of the present invention.

[0046] Spatial and functional relationships between elements (e.g., between crystal elements) can be described using various terms, including "connected," "engaged," "interfaced," and "coupled." Unless explicitly described as "directly," when describing the relationship between a first element and a second element in this specification, the relationship includes a direct relationship between the first element and the second element without other intervening elements, and an indirect relationship between the first element and the second element with one or more intervening elements (spatially or functionally). In contrast, when an element is referred to as being "directly" connected, engaged, interfaced, or coupled to another element, there are no intermediate elements. Other words used to describe the relationship between elements should also be interpreted similarly (such as "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). In the present utility model, the term "and / or" may include any one or more of the relevant listed items or combinations thereof.

[0047] Flowcharts are used in this specification to illustrate the operations performed by the system according to the embodiments of this specification. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, the steps may be processed in reverse order or simultaneously. At the same time, other operations may also be added to these processes, or one or more operations may be removed from these processes.

[0048] For the purpose of illustration, the following description is provided to help better understand the imaging process. It goes without saying that this is not intended to limit the scope of the present invention. For those skilled in the art, under the guidance of the present invention, a certain amount of changes, modifications and / or modifications may be deducted. These changes, modifications and / or modifications do not depart from the scope of the present invention.

[0049] The present invention relates to an ECT detector assembly and a method for determining the location of photon gamma interactions in an ECT detector. The ECT detector assembly includes a detector micro-block, a detector block, a detector module, and an ECT detector. The detector micro-block in the present invention refers to the smallest unit or basic unit for assembling an ECT detector. In some embodiments, a plurality of detector micro-blocks can form a detector block, a plurality of detector blocks can form a detector module (e.g., a detector ring), and a plurality of detector modules can be assembled into a detector of an ECT device (e.g., a PET detector). For example, 64 detector micro-blocks can form an 8x8 array to form a detector block, 5 detector blocks can form a ring-shaped detector module, and 34 detector modules can form a detector. It should be understood that the number of the above components (e.g., detector micro-blocks, detector blocks, detector modules, etc.) can be adjusted according to actual conditions. In addition, the terms "micro-block", "block", "module", "unit", etc. in this document are used to distinguish different components, elements, parts, parts or assemblies at different levels. However, if other terms can achieve the same purpose, these terms can be replaced by other expressions.

[0050] In some embodiments, the detector unit may include detector units arranged side by side along the second direction (or the direction from left to right). Each detector unit may include crystal elements and an optical sensor array. The crystal elements may be arranged into crystal element columns along a first direction (or the front-to-back direction) perpendicular to the second direction, and arranged into crystal element rows along the second direction. Each crystal element may include a first end and a second end, and extend from the first end to the second end along a third direction (or the direction from top to bottom) perpendicular to the first direction and the second direction. The optical sensor array may include optical sensors arranged along the first direction. The first end of the crystal element in each crystal element row may be optically coupled with the optical sensor in the optical sensor array, and the optical bridge may be configured at (located at) the second end of the crystal element in each crystal element column. In this way, the detector microblock may have a U-shaped structure (or an approximately inverted U-shaped structure). When a photon gamma interaction occurs in the crystal element, the output information of the optical sensor may be used to determine the depth of the photon gamma interaction along the extension direction of the crystal element, thereby improving the imaging resolution.

[0051] In some embodiments, each crystal element in the detector microblock may have a long side along a first direction and a short side along a second direction, and the length of the long side along the first direction may be greater than the length of the short side along the second direction. Therefore, multiple detector microblocks in the detector block can be arranged in different orientations, and output information with different resolutions can be obtained, thereby increasing the richness of the output information, thereby improving the accuracy of the position information of the photon gamma interaction and the ECT image generated based on the output information.

[0052] Figure 1 is a schematic diagram of an exemplary imaging system 100 according to some embodiments of the present specification.

[0053] like Figure 1 As shown, in some embodiments, the imaging system 100 may include an imaging device 110, a network 120, one or more terminal devices 130, a processing device 140, and a storage device 150. In some embodiments, the components of the imaging system 100 may be connected to each other via the network 120. Alternatively or additionally, the components of the imaging system 100 may be directly connected to each other.

[0054] The imaging device 110 can scan an object and generate scan data corresponding to the object. The object may include, but is not limited to, one or more organs of a patient, one or more types of tissue, etc. In some embodiments, the imaging device 110 can be a medical scanning device, such as a positron emission tomography (PET) imaging system, a single photon emission computed tomography (SPECT) imaging system, a positron emission tomography-computed tomography (PET-CT) imaging system, a positron emission tomography-magnetic resonance imaging (PET-MRI) imaging system, etc.

[0055] The imaging device 110 may include a frame 111, a detector 112, a scanning area 113, and a workbench 114. An object may be placed on the workbench (examination bed) 114. The workbench 114 may transport the object to a target position in the scanning area 113. The detector 112 may detect radiation rays (e.g., gamma photons) emitted from an object in the scanning area 113. In some embodiments, the detector 112 may include a plurality of detector blocks. The detector blocks may be arranged in a suitable configuration, including but not limited to a ring (e.g., a detector ring), a rectangle, a triangle, an array, etc. In some embodiments, the detector 112 may include a plurality of crystal elements (e.g., scintillation crystals), a plurality of optical sensors, and one or more optical separators as described elsewhere in this specification.

[0056] For the convenience of description, a coordinate system including X-axis, Y-axis and Z-axis is introduced. Figure 1 As shown, the Z-axis direction may refer to the direction along which the object moves into and out of the scanning area 113. The X-axis direction and the Y-axis direction may be perpendicular to each other and form an xy plane.

[0057] In imaging applications, a tracer (e.g., a radioisotope) can be injected into an object (e.g., via a patient's blood vessel). Atoms of the tracer can be incorporated into bioactive molecules. These molecules may accumulate in the patient's tissue. When it is estimated that a sufficient amount of molecules have accumulated in the tissue (e.g., within an hour), the patient can be positioned on the workbench 114. The radioisotope can undergo positron emission decay (i.e., beta decay) and emit positrons. Positrons can interact with electrons in the tissue (the interaction between positrons and electrons is called annihilation). The annihilation of each pair of electrons and positrons can produce a pair of annihilation photons moving in substantially opposite directions. When the annihilation photon hits the crystal element of the detector 112, the annihilation photon can be absorbed by the crystal element to produce an optical photon (e.g., a visible light photon). These optical photons can be detected in turn by one or more optical sensors. The interaction between the annihilation photon and the crystal element that produces the optical photon burst can be referred to as a photon gamma interaction in this article. The depth of the photon gamma interaction along the extension direction of the crystal element where the photon gamma interaction occurs may be referred to as the depth of interaction (DOI).

[0058] The processing device 140 can generate an image based on information associated with the annihilation photons. For example, the processing device 140 can determine the time-of-flight (TOF) information associated with each pair of annihilation photons. The processing device 140 can also determine the DOI information based on the output information of the optical sensor in the detector 112. The processing device 140 can also determine the location where the annihilation occurs based on the time information and the DOI information. After determining the location of the annihilation, the processing device 140 can generate a projection image (also called a sinogram) based on the location of the annihilation. The processing device 140 can reconstruct the image based on the projection image and reconstruction techniques such as filtered back projection (FBP). The reconstructed image can indicate tissues containing a large amount of bioactive molecules (also called tracer molecules) of the tracer. In some embodiments, the number of tracer molecules in a region can be related to the biological function of the tissue in the region. For example, if fluorodeoxyglucose (FDG) is used as a tracer in a PET scan, the number of tracer molecules in the region can be proportional to the metabolic rate of glucose in the region. Since tumors typically consume large amounts of glucose, areas with large amounts of tracer molecules can be identified as tumor tissue in the reconstructed images.

[0059] The network 120 may include any suitable network capable of facilitating information and / or data exchange of the imaging system 100. In some embodiments, one or more components of the imaging system 100 (e.g., the imaging device 110, the terminal device 130, the processing device 140, the storage device 150) may exchange information and / or data with one or more other components of the imaging system 100 through the network 120. For example, the processing device 140 may obtain image data (e.g., TOF information, energy information, DOI information, etc.) from the imaging device 110 through the network 120. The network 120 may include a public network (e.g., the Internet), a private network (e.g., a local area network (LAN)), a wired network, a wireless network (e.g., an 802.11 network, a Wi-Fi network), a frame relay network, a virtual private network (VPN), a satellite network, a telephone network, a router, a hub, a switch, a fiber optic network, a telecommunication network, an intranet, a wireless local area network (WLAN), a metropolitan area network (MAN), a public switched telephone network (PSTN), a Bluetooth network, a ZigBee network, a near field communication (NFC) network, etc., or any combination thereof. In some embodiments, the network 120 may include one or more network access points. For example, the network 120 may include wired and / or wireless network access points, such as base stations and / or Internet exchange points, through which one or more components of the imaging system 100 may connect to the network 120 to exchange data and / or information.

[0060] The terminal device 130 may communicate and / or connect with the imaging device 110, the processing device 140, and / or the storage device 150. For example, a user may interact with the imaging device 110 through the terminal device 130 to control one or more components of the imaging device 110. In some embodiments, the terminal device 130 may include a mobile device 130-1, a tablet computer 130-2, a laptop computer 130-3, etc., or any combination thereof. For example, the mobile device 130-1 may include a mobile control handle, a personal digital assistant (PDA), a smart phone, etc., or any combination thereof. In some embodiments, the terminal device 130 may be part of the imaging device 110 or the processing device 140.

[0061] The processing device 140 can process data and / or information obtained from the imaging device 110, one or more terminal devices 130, the storage device 150, or other components of the imaging system 100. For example, the processing device 140 can process image data (e.g., output information, TOF information, energy information, DOI information, etc.), and reconstruct an image based on the image data. In some embodiments, the processing device 140 can be a single server or a server group. The server group can be centralized or distributed. In some embodiments, the processing device 140 can be local or remote. For example, the processing device 140 can access information and / or data from the imaging device 110, one or more terminal devices 130, and / or the storage device 150 through the network 120. For another example, the processing device 140 can be directly connected to the imaging device 110, one or more terminal devices 130, and / or the storage device 150 to access information and / or data. In some embodiments, the processing device 140 can be implemented on a cloud platform. For example, the cloud platform can include a private cloud, a public cloud, a hybrid cloud, a community cloud, a distributed cloud, a cloud-to-cloud cloud, a multi-cloud, etc., or any combination thereof. In some embodiments, the processing device 140 or a portion of the processing device 140 may be integrated into the imaging device 110 .

[0062] The processing device 140 may include a processor, a storage module, an input / output (I / O), and a communication port. The processor may execute computer instructions (e.g., program code) and perform the functions of the processing device 140 described in this specification. The computer instructions may include, for example, routines, programs, objects, components, data structures, processes, modules, functions, etc. that perform specific functions described in this specification. The storage module may store data / information obtained from the imaging device 110, one or more terminal devices 130, the storage device 150, and / or any other component of the imaging system 100. In some embodiments, the storage module may include a mass storage, a removable memory, a volatile read-write memory, a read-only memory (ROM), etc., or any combination thereof. The I / O may input and / or output signals, data, information, etc. In some embodiments, the I / O may enable user interaction with the processing device 140. In some embodiments, the I / O may include input devices and output devices. Exemplary input devices may include a keyboard, a mouse, a touch screen, a microphone, etc., or any combination thereof. Exemplary output devices may include a display device, a speaker, a printer, a projector, etc., or any combination thereof. The communication port can be connected to a network (e.g., network 120) to facilitate data communication. The communication port can establish a connection between the processing device 140 and the imaging device 110, one or more terminal devices 130, and / or the storage device 150. The connection can be a wired connection, a wireless connection, any other communication connection capable of data transmission and / or reception, and / or any combination of these connections.

[0063] The storage device 150 may store data, instructions, and / or any other information. In some embodiments, the storage device 150 may store data obtained from the imaging device 110, one or more terminal devices 130, and / or the processing device 140. In some embodiments, the storage device 150 may store data and / or instructions used by the processing device 140 to execute or use to complete the exemplary methods described in this specification. In some embodiments, the storage device 150 may store image data (e.g., output information, TOF information, energy information, DOI information, etc.) obtained from the imaging device 110. In some embodiments, the storage device 150 may include a mass storage device, a removable memory, a volatile read-write memory, a read-only memory (ROM), etc., or any combination thereof. In some embodiments, the storage device 150 may be connected to the network 120 to communicate with one or more other components (e.g., the imaging device 110, one or more terminal devices 130, and the processing device 140) in the imaging system 100. In some embodiments, the storage device 150 may be part of the processing device 140.

[0064] It should be noted that the above description is provided for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made under the guidance of the contents of this specification. The features, structures, methods and other features of the exemplary embodiments described in this specification can be combined in various ways to obtain additional and / or alternative exemplary embodiments. For example, the imaging system 100 may also include some other components, such as a patient positioning unit, data acquisition electronics, a power supply and other devices or units. However, these changes and modifications will not deviate from the scope of this specification.

[0065] Figure 2 is a schematic diagram of an exemplary crystal group according to some embodiments of the present specification.

[0066] In some embodiments, a detector (eg, detector 112) may include one or more crystal groups 200A. Crystal groups 200A may be configured to detect annihilation photons generated by annihilation events during scanning of an object.

[0067] like Figure 2 As shown, the crystal group 200A may include a crystal array 210, an optical sensor array 220 optically coupled to the crystal array 210 (in Figure 2 ), one or more first optical separators 212, and one or more second optical separators 213. The crystal array 210 may include a plurality of crystal elements 211 (e.g., crystal elements 211a and 211b), each of which may be configured to receive an annihilation photon (e.g., a gamma photon) from an object. For the purpose of simplicity and illustration, as shown in FIG. Figure 2 The crystal array 210 shown includes only two crystal elements 211, which is not intended to be limiting. The crystal group 200A may include any number or count of crystal elements 211. For example, the crystal array 210 may include three or more crystal elements 211. The optical sensor array 220 may include a plurality of optical sensors 221 configured to detect optical photons emitted from a first end of the crystal element 211.

[0068] The crystal elements 211 of the crystal array 210 may be arranged along a first direction to form a Figure 2The crystal element column shown. Correspondingly, the crystal group can be referred to as a crystal element column. Each crystal element 211 may include a first end S1 (e.g., a bottom end) and a second end S2 (e.g., an upper end), and extend from the first end S1 to the second end S2 along a third direction (e.g., a direction from bottom to top). Among them, the first end S1 of the crystal element 211 refers to an end through which optical photons leave the crystal element 211 to enter the optical sensor 221. The second end S2 of the crystal element 211 refers to an end through which radiation (e.g., gamma rays caused by an annihilation event) enters the crystal element 211. The second end S2 of the crystal element 211 may be closer to the scanned object than the first end S1 of the crystal element 211. In some embodiments, the second end S2 of the crystal element 211 may be coated with a light-reflecting material to completely or substantially completely prevent the optical photons in the crystal element 211 from flowing out of the second end S2 of the crystal element 211.

[0069] The crystal element 211 can be made of any material that can absorb radiation and emit a portion of the absorbed radiation as light. For example, the crystal element 211 can be made of, for example, bismuth germanium oxide (BGO), lutetium orthosilicate (LSO), lutetium yttrium orthosilicate (LYSO), lutetium gadolinium orthosilicate (LGSO), gadolinium orthosilicate (GSO), barium fluoride, sodium iodide, cesium iodide, lead tungstate, yttrium aluminate, lanthanum chloride, lutetium aluminum perovskite, lutetium disilicate, lutetium aluminate, lutetium iodide, thallium bromide, etc., or any combination thereof. Different crystal elements 211 can be made of the same material or different materials.

[0070] The sizes and / or shapes of different crystal elements 211 may be the same or different. For example, the crystal elements 211 of the crystal array 210 may have uniform sizes and shapes. For another example, different crystal elements 211 may have different lengths. The length of the crystal element 211 may refer to the size of the crystal element 211 along its extension direction (i.e., the third direction). In some embodiments, the size and / or shape of the crystal element 211 may vary according to one or more conditions (including, for example, the image resolution of the detector, the size of the detector, etc., or any combination thereof). By way of example only, in order to obtain different spatial resolutions, the crystal element 211 may have different lengths in the first direction and the second direction.

[0071] In some embodiments, a single end of each crystal element 211 of the crystal array 210 can be optically coupled to one optical sensor 221. Each optical sensor 221 of the plurality of optical sensors 221 can be optically coupled to one or more crystal elements 211 of the crystal array 210. Different optical sensors 221 can be coupled to the same number (or count) or different numbers (or counts) of crystal elements 211. When the optical sensor 221 is coupled to the plurality of crystal elements 211, the optical sensor 221 can determine output information corresponding to each crystal element 211 of the plurality of crystal elements 211. The output information can reflect the energy of optical photons excited by the photon gamma interaction in the corresponding crystal element 211 and detected by the optical sensor 211.

[0072] The optical sensor 221 may be coupled to the corresponding crystal element 211 in any suitable manner. For example, the optical sensor 221 may directly contact the corresponding crystal element 211. For another example, the optical sensor 221 may be fixed to the corresponding crystal element 211 by one or more adhesive materials (e.g., light-transmitting glue). For another example, the optical sensor 221 may be single-endedly coupled to the corresponding crystal element 211 by a light-transmitting material (e.g., a piece of glass). In some embodiments, one or more optical sensors 221 may be optically coupled to a crystal element 211 (e.g., crystal element 211a or 211b) to receive photons from a single end (e.g., first end S1) of the crystal element 211. A detector that uses one or more optical sensors 221 to detect photons from a single end of each crystal element 211 may be referred to as a detector having a single-ended readout structure.

[0073] In some embodiments, the optical sensor 221 may include a phototube, a photomultiplier tube (PMT), a photodiode, an active pixel sensor, a bolometer, a gas ionization detector, a photoresistor, a phototransistor, an avalanche photodiode (APD), a single photon avalanche photodiode (SPAD), a silicon photomultiplier (SiPM), a digital silicon photomultiplier (DSiPM), etc., or any combination thereof. Different optical sensors 221 may be optical sensors of the same type or different types.

[0074] In some embodiments, light sharing between two adjacent (or neighboring) crystal elements 211 belonging to the same crystal group 200A may be allowed, while light sharing between two adjacent crystal groups may be limited or substantially limited, so as to facilitate the determination of the location of the photon gamma interaction. If there are no other crystal elements between the two crystal elements 211, the two crystal elements 211 may be considered to be adjacent or adjacent to each other. In some embodiments, two adjacent or neighboring crystal elements may be separated by a void space, an item other than a crystal element (e.g., a film, a coating, a material layer different from the material of any crystal element of the adjacent crystal element, etc.), etc., or any combination thereof. By way of example only, there may be a space between two adjacent crystal elements of the same crystal group, a portion of which may be filled with an optical separator (e.g., a second optical separator 213 described elsewhere in this specification), and a portion of which may be empty. For another example, there may be a space between two adjacent crystal elements of the same crystal group, a portion of which may be filled with an optical separator (e.g., a second optical separator described elsewhere in this specification), and another portion of which may be filled with an optical propagation medium. The optical transmission medium can be any material that allows light to pass through (e.g., glass, anti-reflection material), which can achieve light sharing between two adjacent crystal elements of the same crystal group. Figure 2 As shown, a portion of the space between the crystals 211a and 211b is filled with an optical propagation medium 214, and photons can propagate between the crystals 211a and 211b through the optical propagation medium 214. The optical propagation medium 214 can be disposed between each pair of adjacent crystal elements in the crystal group 200A (or crystal element column), and the optical propagation medium 214 can extend from the second end S2 of the corresponding pair of adjacent crystal elements to the second optical separator 213 between the corresponding pair of adjacent crystal elements.

[0075] In some embodiments, the width of the second optical separator 213 and the optical propagation medium 214 can be determined according to actual use requirements. Taking the optical propagation medium 214 as an example, the width of the optical propagation medium 214 can refer to the dimension along the first direction. For example, the width of the optical propagation medium 214 can be determined according to the length of the crystal element. For example, the width of the optical propagation medium 214 can be positively correlated with the length of the crystal element. As an example only, the width of the optical propagation medium 214 can be within a certain range, for example, 1-5 mm, 1.5-4.5 mm, 2-4 mm, 2.5-3.5 mm, etc. The length of the optical propagation medium 214 can be determined according to the second optical separator 213. The length of the optical propagation medium 214 can refer to the length of the optical propagation medium 214 along the third direction. For example, in the same crystal group, the sum of the length of the optical propagation medium 214 and the length of the second optical separator 213 can be equal to the length of any crystal element in the crystal group.

[0076] If there are no other crystal groups between two crystal groups, then the two crystal groups can be considered to be adjacent or adjacent to each other. In some embodiments, two adjacent or adjacent crystal groups can be separated by void spaces, items other than crystal elements (e.g., films, coatings, material layers different from the materials of any crystal elements of the crystal elements of the adjacent adjacent crystal groups, etc.), etc., or any combination thereof. By way of example only, there can be space between two adjacent crystal groups, a portion of which can be filled with an optical separator (e.g., a first optical separator described elsewhere in this specification), and a portion of which can be empty. For another example, the space between two adjacent crystal groups can be substantially completely filled with an optical separator (e.g., a first optical separator described elsewhere in this specification).

[0077] To control light transmission between two adjacent crystal elements 211 or two adjacent crystal groups, multiple optical separators may be used in crystal group 200A. The optical separators may include reflective films, reflective foils, reflective coatings (e.g., white reflective coatings), or any other material that may block or substantially block light transmission. Figure 2 The shaded areas shown represent one or more optical separators configured to block or partially block light transmission between crystal elements 211. For example, first optical separator 212 may substantially or completely cover the side surface of crystal element 211a to prevent optical photons in crystal group 200A from traveling to the adjacent crystal group from the side facing the adjacent crystal group. Figure 2 (not shown). The first length of the first optical separator 212 may be equal to the length of the crystal element 211a.

[0078] The second optical separator 213 may be located between each pair of adjacent crystal elements in the crystal group (or crystal element column). The second optical separator 213 may extend from the first end S1 of the corresponding pair of adjacent crystal elements without reaching the second end S2 of the corresponding pair of adjacent crystal elements to partially block the optical photon transmission between the corresponding pair of adjacent crystal elements. For example, the second optical separator 213 may be located between the crystal elements 211a and 211b. The second optical separator 213 may extend from the first end S1 of the crystal element 211a or 211b along the third direction. The second length of the second optical separator 213 may be less than the length of the crystal element 211a or 211b, so that the second optical separator 213 may partially block the optical photon transmission between the crystal elements 211a and 211b. The first length of the first optical separator 212 may be greater than the second length of the second optical separator 213. The length of the optical separator may refer to the length of the optical separator along the extension direction (i.e., the third direction) of the crystal element 211.

[0079] In some embodiments, the length of the second optical separator 213 may be equal to or greater than half the length of at least one of the crystal elements 211a and 211b. In some embodiments, the length of the second optical separator 213 may be equal to N% of the length of the crystal element 211a or 211b. N may have any suitable positive value (the value of N is less than 100). In some embodiments, N may be within a certain range, such as within a range of 30 to 90, 50 to 85, etc. For example, N may be 30, 40, 50, 60, 70, 80, 85, or 90. N may be a parameter used in determining the position of the photon gamma interaction in the crystal group 200A. In some embodiments, N may be a default parameter stored in a storage device (e.g., storage device 150). Alternatively, N may be manually set according to different situations or determined by one or more components of the imaging system 100. In some embodiments, the material of the second optical separator 213 may be the same as or different from the material of the first optical separator 212.

[0080] It should be noted that Figure 2 The examples shown in are provided only for the purpose of illustration, not for limiting the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. In some embodiments, the crystal array 210 may include any suitable number or count of crystal elements 211. For example, the crystal array 210 may include an even number (such as 2, 4, 6, 8 or 12) of crystal elements 211. The crystal elements 211 may be arranged in any suitable manner. For example, the crystal elements 211 of the crystal array 210 may be arranged along the second direction to form a crystal element row.

[0081] Figure 3A and Figure 3B is a schematic diagram of an exemplary photon gamma interaction occurring in an exemplary crystal group according to some embodiments of the present specification.

[0082] The photon gamma interaction occurring in crystal group 200A may excite one or more optical photons that may be detected by corresponding optical sensor 221a and / or optical sensor 221b as described elsewhere in this specification. The number or count of optical photons detected by optical sensor 221a or optical sensor 221b may be associated with the location of the photon gamma interaction in crystal group 200A. For example, Figure 3A As shown, the photon gamma interaction 1 occurs at the top of the second optical separator 213 (at Figure 3AThe optical photons generated by the photon gamma interaction 1 may be blocked or substantially blocked by the second optical separator 213 and cannot travel into the crystal element 211b. Therefore, all or almost all of the optical photons excited by the photon gamma interaction 1 may be detected by the optical sensor 221a. For example only, Figure 3A As shown, the photon gamma interaction 1 can generate multiple optical photons. Some of the multiple optical photons can travel directly to the optical sensor 221a along the photon travel paths 1a and 1b and be detected by the optical sensor 221a. Some of the multiple optical photons can travel along the photon travel path 1c, be reflected by the second optical separator 213, and then be detected by the optical sensor 221a.

[0083] For example, Figure 3B As shown, the photon gamma interaction 2 occurs at the top of the second optical separator 213 (at Figure 3B The optical photons excited by the photon gamma interaction 2 may be partially blocked by the second optical separator 213 from traveling into the crystal element 211b. Therefore, the optical photons may be detected by both the optical sensor 221a and the optical sensor 221b. As an example only, the photon gamma interaction 2 may generate a plurality of optical photons. Some of the plurality of optical photons may be directly detected by the optical sensor 221a along the photon travel paths 2a and 2b, and some of the optical photons may travel along the photon travel path 2c into the crystal element 211b and be detected by the optical sensor 221b.

[0084] Figure 4A is a schematic diagram of an exemplary crystal group 200B according to some embodiments of the present specification.

[0085] The crystal group (or crystal element array) 200B may be similar to Figures 2 to 3BThe crystal group 200A described, except that the second end S2 of the crystal elements 211a and 211b can be integrated into a single end. In some embodiments, the crystal group 200B can be manufactured by partially cutting a single crystal block into crystal elements 211a and 211b. The cut can extend from the first end S1 of the crystal block to its second end S2, and the cut can extend to a depth that does not reach the second end S2. That is, the second ends S2 of the crystal elements 211a and 211b in each crystal group 200B (or crystal element column) can be integrated into a whole piece as an optical bridge. The second optical separator 213 can be made by filling the cutting groove of the crystal block with one or more reflective materials. In this case, light transmission between the crystal element 211a and the crystal element 211b can be allowed in the uncut portion near the second end S2, and light transmission between the crystal element 211a and the crystal element 211b can be prevented in the cut portion near the first end S1. The first optical separator 212 can be formed by coating the other side surfaces of the crystal element 211a and / or the crystal element 211b with a light reflecting material. That is, the light reflecting material can be filled between the crystal group 200B and the adjacent crystal group. In this case, the crystal group 200B and the adjacent crystal group ( Figure 4A Light transmission between the two (not shown).

[0086] In some embodiments, the location of the photon gamma interaction 3 in the crystal group 200B can be determined based on the output information of the optical sensor 221a and the optical sensor 221b. The output information can reflect the energy of the optical photons excited by the photon gamma interaction 3 and detected by the optical sensor 221a and / or the photon sensor 221b. In some embodiments, the crystal element (also referred to as the target crystal element) in which the photon gamma interaction 3 occurs and / or the depth of the photon gamma interaction 3 in the target crystal element can be determined based on the output information.

[0087] Figure 4B is a schematic diagram of an exemplary crystal group 200C according to some embodiments of the present specification.

[0088] The crystal group (or crystal element array) 200C can be similar to Figures 2 to 3B The crystal group 200A described above differs in that the length of the second optical separator 213 is equal to at least one of the crystal element 211a and the crystal element 211b (i.e., the second optical separator 213 covers the crystal element 211a or the crystal element 211b), and the light transmission between the crystal elements 211a and 211b in the crystal group 200C is achieved through the optical transmission medium 410 installed at the second end S2. Figure 4BAs shown, the crystal group 200C may include a crystal element (eg, crystal element 211a, crystal element 211b), an optical sensor (eg, optical sensor 221a, optical sensor 221b) optically coupled to the crystal element (eg, Figure 4B ), optical separators (eg, the first optical separator 212, the second optical separator 213), and an optical bridge.

[0089] The optical bridge may include an optical transmission medium 410 covering the second ends of the crystal elements 211a and 211b in the crystal group 200C. Each side surface (e.g., side surface 410a and side surface 410b) and a surface 410c of the second end S2 of the optical transmission medium 410 of the adjacent crystal group facing the crystal group 200C may be coated with a reflective material to completely or substantially completely prevent optical photons in the crystal group 200C from leaving the optical transmission medium 410 from the side of the optical transmission medium 410. The optical transmission medium 410 may be made of any material that allows light to pass through (e.g., glass, scintillating crystals). Optical photons excited by a photon gamma interaction occurring in one crystal element of the crystal group 200C may travel to the optical transmission medium 410, be reflected one or more times by the side of the optical transmission medium 410, and then travel to another crystal element of the crystal group 200C. As Figure 4B As shown, optical photons generated by the photon gamma interaction 4 in the crystal element 211a may travel through the optical transmission medium 410 (eg, along the photon movement path 4b) into the crystal element 211b.

[0090] The location of the photon gamma interaction occurring in crystal group 200C can be determined based on the output information of optical sensor 221a and optical sensor 221b optically coupled to crystal group 200C. In some embodiments, the location of the photon gamma interaction can be determined based on the energy detected by optical sensor 221a and optical sensor 221b. For example, Figure 4B As shown, the photon gamma interaction 4 occurs at a position closer to the second end S2 than the first end S1 of the crystal element 211a. A portion of the optical photons generated by the photon gamma interaction 4 can travel directly to the optical sensor 221a along the photon travel path 4a and the photon travel path 4c, and be detected by the optical sensor 221a; a portion of the optical photons can travel along the photon travel path 4b via the optical transmission medium 410 to the crystal element 211b, and be detected by the optical sensor 221b.

[0091] In some embodiments, the location of the photon gamma interaction in the crystal group 200C can be determined based on the time when the photons generated by the photon gamma interaction are received by the optical sensor 221a and the optical sensor 221b. Taking the photon gamma interaction 4 as an example, the time difference between the first time point when the optical sensor 221a receives the photon (e.g., the photon traveling along the photon travel path 4a) and the second time point when the optical sensor 221b receives the photon (e.g., the photon traveling along the photon travel path 4b) can be determined. The DOI of the photon gamma interaction 4 can be estimated based on the time difference and the speed of light. A shorter time difference can indicate that the photon gamma interaction 4 occurs at a position closer to the second end of the crystal element 211a.

[0092] As can be seen from the foregoing description, crystal group 200, crystal group 200B and crystal group 200C all have a U-shaped (inverted U-shaped) structure, and the U-shaped (inverted U-shaped) structure includes a U-shaped (inverted U-shaped) optical path. The U-shaped optical path refers to a path with a U shape, along which photons can be transmitted. In this specification, the orientation of the U-shaped optical path is not restricted. For example, for each crystal group 200, crystal group 200B and crystal group 200C, the U-shaped optical path is inverted. Light transmission can be achieved at a position close to the second end S2 of the crystal element (i.e., corresponding to the lower part of the U shape), while light transmission cannot be achieved at a position close to the first end S1 of the crystal element (i.e., corresponding to the upper part of the U shape or the lower part of the inverted U shape). In this specification, a crystal group with a U-shaped optical path can be referred to as a U-shaped crystal group. The portion of the U-shaped crystal group that allows light to pass can be referred to as an optical bridge or an optical window. For example, the uncut ends of the crystal elements 211a and 211b in the crystal group 200B can be regarded as an optical bridge, and the optical transmission medium 410 covering the second ends S2 of the crystal elements 211a and 211b in the crystal group 200C can be regarded as an optical bridge. In other embodiments, the optical transmission medium 214 in the crystal group 200A can be regarded as an optical bridge. It should be understood that the U-shaped crystal group can include more than two crystal elements, as long as the second ends of the crystal elements can achieve optical transmission and the first ends cannot achieve optical transmission.

[0093] The special structure of the U-shaped crystal group can be used to determine DOI information, that is, to determine the depth of the photon gamma interaction in the extension direction of the crystal element. In some embodiments, an ECT detector assembly (e.g., a U-shaped detector, a detector unit, etc.) that can realize DOI calculation can be constructed based on the U-shaped crystal group. For more description of the ECT detector assembly, please refer to other contents of this specification (e.g., Figures 5A-6F and related descriptions).

[0094] Figure 5Ais a schematic diagram of an exemplary detector microblock 300 according to some embodiments of the present specification. Figure 5B is a schematic diagram of a rear view of an exemplary detector microblock 300 according to some embodiments of the present specification. Figure 5C is a schematic diagram of a right side view of an exemplary detector microblock 300 according to some embodiments of the present specification. Figure 5D is a schematic diagram of a top view of an exemplary detector microblock 300 according to some embodiments of the present specification.

[0095] The detector microblock 300 can be configured to detect annihilation photons generated by annihilation events during an ECT scan of an object. In some embodiments, the detector microblock 300 can include one or more detector units. The detector units can be arranged side by side along the second direction. Each of the one or more detector units can include one or more U-shaped crystal groups (e.g., crystal group 200A, crystal group 200B, crystal group 200C). Similar to the U-shaped crystal group, the U-shaped detector can also have a U-shaped structure and include a U-shaped light path. Therefore, the detector unit can also be referred to as a U-shaped detector unit.

[0096] like Figures 5A-5D As shown, the detector microblock 300 may include a first detector unit 301 and a second detector unit 302. The first detector unit 301 may include a crystal array 310, an optical sensor array 320 optically coupled to the crystal array, one or more optical separators and an optical bridge. The crystal array 310 may include a plurality of crystal elements 311 (e.g., crystal element 311a, crystal element 311b, crystal element 311c and crystal element 311d), and the plurality of crystal elements 311 may be arranged into crystal element columns (e.g., crystal element column 350a and crystal element column 350b) (also referred to as crystal groups) along a first direction perpendicular to the second direction, and arranged into crystal element rows along the second direction. For example, two crystal elements may be arranged in each crystal element column of the detector unit along the first direction, and two crystal elements may be arranged in each crystal element row of the detector unit along the second direction. Each of the plurality of crystal elements 311 may have a first end S1 (e.g., a bottom end) and a second end S2 (e.g., an upper end), and extend from the first end S1 to the second end S2 along a third direction perpendicular to the first direction and the second direction. The optical sensor array 320 may include a plurality of optical sensors (eg, optical sensors 321 a and 321 b ), and the optical sensors 321 a and 321 b may be arranged in an optical sensor column along a first direction.

[0097] Similarly, the second detector unit 302 may include a crystal array 330, an optical sensor array 340 optically coupled to the crystal array, and one or more optical separators. The crystal array 330 may include a plurality of crystal elements 331 (e.g., crystal element 331a, crystal element 331b, crystal element 331c, and crystal element 331d), and the optical sensor array 340 may include a plurality of optical sensors (e.g., optical sensor 341a and optical sensor 341b). An optical bridge may be configured at the second end of the crystal element in each crystal element column.

[0098] Each crystal element (e.g., each of crystal elements 311a, 311b, 311c, 311d, 331a, 331b, 331c, and 331d) may be configured to receive annihilation photons from the object. Figure 5A As shown, the crystal elements 311 of the crystal array 310 and the crystal elements 331 of the crystal array 330 in the detector microblock 300 can form two crystal rows arranged in parallel along the second direction and four crystal element columns arranged in parallel along the first direction. In some embodiments, the second direction can be orthogonal or approximately orthogonal to the first direction. In some embodiments, both the first direction and the second direction can be orthogonal or approximately orthogonal to the extension direction (i.e., the third direction) of the crystal elements.

[0099] Each crystal element of the crystal array 310 and the crystal array 330 may be similar to Figures 2 to 4BCrystal elements described. In some embodiments, each crystal element may have a long side along a first direction and a short side along a second direction. In this specification, a long side refers to a side of a crystal element parallel to a first direction (i.e., the arrangement direction of the crystal element in the crystal group), and a short side refers to a side parallel to the second direction. For example, the length of the long side along the first direction can be determined according to the length of the optical sensor 221. In another embodiment, the length of the long side along the first direction may be within a first range, for example, 1-5 mm, 2-4.5 mm, 2.5-4 mm, 3-4 mm, etc. The length of the short side along the second direction may be within a second range, for example, 1-5 mm, 1.5-4 mm, 2-3 mm, etc. In some embodiments, the length of the long side of the crystal element may be greater than the length of the short side of the crystal element. For example, the ratio of the length of the long side along the first direction to the length of the short side along the second direction may be greater than 1 and less than 5. For example, the ratio of the length of the long side along the first direction to the length of the short side along the second direction may be 1.2, 1.5, 1.8, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, etc. Since the area of ​​the crystal element (i.e., the product of the length of the long side of the crystal element and the length of the short side) is positively correlated with the time resolution of the crystal element, in order to ensure that the time resolution meets the actual requirements, the length of the short side of the crystal element may be greater than the preset length threshold of the short side. In addition, as the length of the short side of the crystal element decreases, the number of crystal elements in the detector microblock 300 may increase, and the number of optical separators in the detector microblock 300 may increase, thereby reducing the sensitivity of the detector microblock 300. Therefore, the preset length threshold of the short side may be determined by considering the time resolution and sensitivity of the detector microblock 300. As an example only, the length of the long side along the first direction may be 4.3 mm, and the length of the short side along the second direction may be 2.1 mm. For another example, the length of the long side along the first direction may be 3.0 mm, and the length of the short side along the second direction may be 1.5 mm. Since the length of the long side along the first direction is not equal to the length of the short side along the second direction, the resolution of the crystal element in the first direction may be different from the resolution in the second direction. Therefore, by arranging the detector micro-blocks 300 in different directions, output information with different resolutions can be collected.

[0100] In some embodiments, in each detector unit, the crystal elements may form a plurality of U-shaped crystal groups along the first direction. Taking the first detector unit 301 as an example, the first detector unit 301 may include four crystal elements 311a, 311b, 311c, and 311d, forming a 2×2 crystal array. Crystal elements 311a and 311c may form a crystal element column (or crystal group) 350a, and crystal elements 311b and 311d may form a crystal element column (or crystal group) 350b. It should be noted that Figure 5AThis is provided for illustration purposes only and is not intended to limit the scope of the present description. Each crystal element column 350 may include any number of crystal elements 311 .

[0101] The crystal element array 350 may be similar to Figure 2 Crystal group 200A, Figure 4A Crystal group 200B or Figure 4B The crystal group 200C in the embodiment of the present invention. The light transmission between and within the crystal group can be controlled by applying one or more first optical separators 312 and one or more second optical separators 313. The first optical separator 312 can be similar to the first optical separator 212, and the second optical separator 313 can be similar to the second optical separator 213, which will not be described in detail here. For example, see Figure 5C A second optical separator 313 is disposed between a pair of adjacent crystal elements 311a and 311c in the crystal element column 350a, and the separator extends from a first end (e.g., bottom end) S1 of the corresponding pair of adjacent crystal elements 311a and 311c, but does not reach a second end (e.g., upper end) S2 of the corresponding pair of adjacent crystal elements 311a and 311c, so as to partially block the optical photon transmission between the corresponding pair of adjacent crystal elements 311a and 311c. An optical propagation medium 316 may serve as an optical bridge and be disposed between a pair of adjacent crystal elements 311a and 311c in the crystal element column 350a. The optical propagation medium 316 extends from the second end S2 of the corresponding pair of adjacent crystal elements 311a and 311c to the second optical separator 313 between the corresponding pair of adjacent crystal elements 311a and 311c. That is, in the crystal element array 350a, the sum of the length of the optical propagation medium 316 and the length of the second optical separator 313 may be equal to the length of the crystal element 311a or the crystal element 311c in the crystal element array 350a. By using the second optical separator 313 and the optical propagation medium 316, the optical sharing of the crystal element 311a and the crystal element 311c in the crystal group 350a at the second end may be achieved. For another example, the first optical separator 312 may be disposed between adjacent crystal elements of adjacent detector microblocks.

[0102] In some embodiments, in each detector unit, the transmission between adjacent crystal groups can be controlled by applying a third optical separator 314. The third optical separator 314 can be configured between each pair of adjacent crystal element columns in the detector unit and extend from the first end of the crystal element in the corresponding pair of adjacent crystal element columns to the second end of the crystal element in the corresponding pair of crystal element columns to block the optical photon transmission between the corresponding pair of crystal element columns. Figure 5A and 5BAs shown, the third optical separator 314 can be configured between adjacent crystal element columns 350a and crystal element columns 350b in the detector unit 301, and the third optical separator 314 extends from the first end S1 of the crystal elements 311a, 311b, 311c and 311d in a corresponding pair of adjacent crystal element columns 350a and 350b to the second end S2 of the crystal elements 311a, 311b, 311c and 311d in a corresponding pair of adjacent crystal element columns 350a and 350b, for blocking the transmission of optical photons between the corresponding pair of crystal element columns 350a and 350b.

[0103] The length of each third optical separator 314 may be equal to or less than the length of at least one crystal element on both sides thereof. The lengths of different third optical separators 314 may be the same or different. Figure 5B As shown, the length of the third optical separator 314 can be equal to the length of the crystal elements 311a and 311b to block or substantially block the light transmission between the crystal element columns 350a and 350b. In other words, the light transmission between the two crystal element columns of the same detector unit can be blocked.

[0104] In some embodiments, in the detector microblock 300, optical transmission between detector units can be controlled by applying a fourth optical separator 315 and a second optical bridge 317. The fourth optical separator 315 can be located between each pair of adjacent detector units in the detector microblock and extend from the second end S2 of the crystal element in the corresponding pair of adjacent detector units without reaching the first end S1 of the crystal element in the corresponding pair of adjacent detector units to partially block the optical photon transmission between the corresponding pair of adjacent detector units. The second optical bridge 317 can be located between each pair of adjacent detector units in the detector microblock and extend from the first end S1 of the crystal element in the corresponding pair of adjacent detector units without reaching the second end S2 of the crystal element in the corresponding pair of adjacent detector units to allow the optical photon transmission between the corresponding pair of adjacent detector units.

[0105] like Figure 5A and 5B As shown, the fourth optical separator 315 and the second optical bridge 317 may be located between adjacent first detector units 301 and second detector units 302. For example, the light transmission between the first detector unit 301 and the second detector unit 302 may be controlled by the fourth optical separator 315 and the second optical bridge 317. The length of the fourth optical separator 315 may be equal to or less than the length of the crystal elements on both sides thereof. The lengths of the fourth optical separators 315 in different detector microblocks 300 may be the same or different. For example, Figure 5A and Figure 5BAs shown, part of the space between the first detector unit 301 and the second detector unit 302 (for example, between the crystal element 311d and the crystal element 331c) is filled with a fourth optical separator 315 for blocking the optical photon transmission between the crystal elements at the second end S2, and another part of the space is filled with a second optical bridge 317 for allowing the optical photon transmission between the first detector unit 301 and the second detector unit 302 at the first end S1. In some embodiments, in the detector microblock 300, the sum of the length of the second optical bridge 317 and the length of the fourth optical separator 315 may be equal to the length of the crystal element of the detector microblock 300.

[0106] In some embodiments, the optical sensor array of each detector unit may include two optical sensors. Taking the first detector unit 301 as an example, its optical sensor array 320 may include two optical sensors 321 (e.g., optical sensor 321a and optical sensor 321b) arranged along a first direction. Each optical sensor 321 may be optically coupled to one or more crystal elements of the crystal array 310. For example, the first end of the crystal element in each crystal element row may be optically coupled to an optical sensor of the optical sensor array. For example, Figures 5A-5C As shown, the optical sensor 321a can completely cover the first end S1 of the crystal element 311a and the crystal element 311b in the same row, the optical sensor 321b can completely cover the first end S1 of the crystal element 311c and the crystal element 311d in the same row, the optical sensor 341a can completely cover the first end S1 of the crystal element 331a and the crystal element 331b in the same row, and the optical sensor 341b can completely cover the first end S1 of the crystal element 331c and the crystal element 331d in the same row. The optical sensor is located at the end of the crystal element and is configured to detect optical photons from a single end of the corresponding crystal element. The manner in which the optical sensor is optically coupled to its corresponding crystal element can be any suitable manner as described elsewhere in this specification (for example, Figure 2 and its description).

[0107] It should be noted that Figures 5A-5D Each optical sensor corresponds to two crystal elements along the second direction (i.e., the coupling ratio between the optical sensor and the crystal element is 1:2) is provided for illustrative purposes only and is not intended to limit the scope of this specification. For example, the optical sensor may correspond to one, three, four or more crystal elements according to its crystal position recognition capability and / or light collection efficiency.

[0108] By applying the special design structure of the detector microblock 300, the position information of the photon gamma interaction occurring in the detector microblock 300 can be determined based on the output information of multiple optical sensors. Figure 5C As shown, the photon gamma interaction occurs at a position closer to the second end S2 of the crystal element 311c than the first end S1. A portion of the optical photons generated by the photon gamma interaction 5 can travel directly to the optical sensor 321b along the photon moving path 5a and the photon moving path 5b and be detected by the optical sensor 321b. A portion of the optical photons can enter the crystal element 311a through the optical propagation medium 316 along the photon moving path 5c and be detected by the optical sensor 321a. The position information of the photon gamma interaction 5 in the crystal element column 350a (i.e., the target crystal element column) of the first detector unit 301 can be determined based on the output information of the optical sensors 321a and 321b. The output information can reflect the energy of the photons excited by the photon gamma interaction 5 and detected by the optical sensor 321a and / or the optical sensor 321b. In some embodiments, the depth of the photon gamma interaction 5 in the crystal element 311c (wherein the photon gamma interaction 5 occurs) (also referred to as the target crystal element) can be determined based on the output information. For more information on determining the position information of the photon gamma interaction in the detector microblock, please refer to other contents in this specification (for example, Figure 8 and its related instructions).

[0109] It should be noted that the above description is provided for illustrative purposes only and is not intended to limit the scope of the present specification. For those of ordinary skill in the art, various changes and modifications can be made under the guidance of the present specification. However, these changes and modifications do not depart from the scope of the present specification. In some embodiments, the detector microblock 300 can include any suitable number or count of detector units. For example, the detector microblock 300 can include, for example, three, four, five, six, etc., number of detector units.

[0110] Figure 6A-6F is a schematic top view of an exemplary detector block according to some embodiments of the present specification.

[0111] In some embodiments, the detector block may include a plurality of detector microblocks (e.g., detector microblock 300) arranged in a certain arrangement (or configuration). For example, the plurality of detector microblocks 300 may be arranged in the form of a block array. As an example only, based on the size of the detector block and the detector microblock 300, the number (or count) of the plurality of detector microblocks 300 in the detector block may be determined.

[0112] In some embodiments, multiple detector microblocks 300 in a detector block may have the same orientation. For ease of description, the short side direction of the crystal element in the detector microblock 300 may be defined as the orientation of the detector microblock, which may be perpendicular to the plane composed of the extension direction and the long side direction of each crystal element in the detector microblock 300. Figure 5A Taking the detector micro-block 300 in FIG. 1 as an example, the orientation of the detector micro-block 300 can be represented by an arrow parallel to the short side of the crystal element in the detector micro-block 300 .

[0113] In some embodiments, the short sides of the crystal elements in the plurality of detector micro-blocks 300 may be parallel to each other. That is, the orientation of each of the plurality of detector micro-blocks 300 in the detector block may be the same. Fig. 6A As shown, the detector block 600A may include eight detector microblocks 300 with the same orientation, forming a block array with four rows and two columns. The long side of each crystal element in each detector microblock 300 may be parallel to the row direction of the block array, and the short side may be parallel to the column direction of the block array. In other words, the orientation of each detector microblock 300 is parallel to the column direction. For another example, Figure 6B As shown, the detector block 600B may include eight detector microblocks 300, forming a block array of four rows and two columns. The long side of each crystal element in each detector microblock 300 is parallel to the column direction of the block array, and the short side is parallel to the row direction of the block array. In other words, the orientation of each detector microblock 300 is parallel to the row direction.

[0114] In some embodiments, the short sides of the crystal elements in one or more first detector units in the plurality of detector micro-blocks 300 may be perpendicular to the short sides of the crystal elements in one or more second detector units in the plurality of detector micro-blocks 300. That is, the plurality of detector micro-blocks 300 in the detector block may have different orientations.

[0115] For example, Figure 6C As shown, the detector block 600C may include 8 detector microblocks 300, forming a block array of four rows and two columns. Four first detector microblocks 300a may form a left column, and four second detector microblocks 300b may form a right column. In the left column, the orientation of each first detector microblock 300a may be parallel to the column direction. In the right column, the orientation of each second detector microblock 300b may be parallel to the row direction. In other words, the orientation of the first detector microblock 300a in the left column may be perpendicular to the orientation of the second detector microblock 300b in the right column.

[0116] For example, Fig.6DAs shown, the detector block 600D may include 64 detector microblocks 300, forming an array of eight rows and eight columns. The short sides of the crystal elements of each pair of adjacent detector microblocks in the plurality of detector microblocks 300 may be perpendicular to each other to form a checkerboard-like structure. That is, each pair of adjacent detector microblocks in the plurality of detector microblocks may include a first detector microblock and a second detector microblock to form a checkerboard-like structure. Each pair of adjacent detector microblocks may refer to two detector microblocks adjacent to each other in the same column or the same row. For example only, Fig.6D As shown, the orientations of adjacent detector micro-blocks 300c and 300d may be perpendicular to each other, and the orientations of adjacent detector micro-blocks 300e and 300f may be perpendicular to each other. Therefore, the detector block 600D may have a checkerboard structure.

[0117] For example, Fig. 6E As shown, the detector block 600E may include 16 detector microblocks 300, forming a block array of four rows and four columns. The two columns of detector microblocks on the left may have the same arrangement as the detector block 600C, and the two columns of detector microblocks on the right may have the same arrangement as the detector block 600D.

[0118] In some embodiments, the plurality of detector micro-blocks 300 in the detector block may include a first sub-block and a second sub-block. Each of the first sub-block and the second sub-block may include a plurality of detector micro-blocks, the detector micro-blocks of each first sub-block may have a first arrangement, and the detector micro-blocks of each second sub-block may have a second arrangement different from the first arrangement. For example only, Fig. 6F As shown, the detector block 600F includes first sub-blocks 610 and 640 and second sub-blocks 620 and 630. The first sub-blocks 610 and 640 may have the same arrangement as the detector block 600C, and the second sub-blocks 620 and 630 may have the same arrangement as the detector block 600D.

[0119] In some embodiments, the plurality of detector micro-blocks 300 in the detector block may be arranged randomly. For example, the orientation of each detector micro-block 300 in the detector block may be randomly determined. For example, when the parameter value corresponding to the orientation is 0, the orientation of the detector micro-block 300 is parallel to the column direction. When the parameter value corresponding to the orientation is 1, the orientation of the detector micro-block 300 is parallel to the row direction. The parameter value corresponding to the orientation of each detector micro-block 300 may be randomly determined according to the system default setting, or manually set by the user. Then, the plurality of detector micro-blocks 300 may be arranged according to the parameter value corresponding to the orientation of each detector micro-block 300, thereby forming a detector block. It should be noted that the parameter values ​​0 and 1 are provided for illustrative purposes and are not intended to limit the scope of this specification.

[0120] In some embodiments, since the detector microblock 300 has a U-shaped structure, the slot / opening direction of the U-shaped structure of the detector microblock 300 can be defined as the orientation of the detector microblock. The slot direction refers to the through direction of the slot in the U-shaped structure. For example, the slot direction can be Figure 5A The second direction in .

[0121] See also Figure 6A-6D ,like Fig. 6A As shown, the orientation of each detector microblock 300 in the detector block 600A is parallel to the column direction. Figure 6B As shown, the orientation of each detector microblock 300 in the detector block 600B is parallel to the row direction. Figure 6C As shown, in the detector block 600C, the orientation of each detector microblock 300a in the left column is parallel to the column direction, and the orientation of each detector microblock 300b in the right column is parallel to the row direction. In other words, the orientation of the detector microblock 300a in the left column is perpendicular to the orientation of the detector microblock 300b in the right column. Fig.6D As shown, the detector block 600D includes 64 detector microblocks 300, forming an array of eight rows and eight columns. Each row of detector microblocks 300 in the detector block 600D parallel to the diagonal direction of the block array can have the same orientation, and the orientations of adjacent rows of detector microblocks parallel to the diagonal direction can be perpendicular to each other. For example, the first row of detector microblocks from detector microblock 300c to detector microblock 300e is parallel to the diagonal direction of the block array, and the orientation of each detector microblock 300 in the first row of detector microblocks is parallel to the row direction of the block array. The second row of detector microblocks from detector microblock 300d to detector microblock 300f is parallel to the diagonal direction of the block array, and the orientation of each detector microblock 300 in the second row of detector microblocks is parallel to the column direction of the block array. In other words, the orientation of each detector microblock 300 in the first row of detector microblocks can be perpendicular to the orientation of each detector microblock 300 in the second row of detector microblocks.

[0122] By arranging multiple detector microblocks in different arrangements, multiple detector blocks can be designed, thereby improving the applicability of the detector microblocks. In some embodiments, the detector block may include one or more first detector microblocks and one or more second detector microblocks, and the orientation of the one or more first detector microblocks is different from the orientation of the one or more second detector microblocks. Therefore, the detector block can be used to collect output information of different resolutions, thereby increasing the richness of the output information, thereby improving the accuracy of the position information of the photon gamma interaction and the ECT image generated based on the output information.

[0123] Figure 71 is a block diagram of an exemplary processing device 140 according to some embodiments of the present specification. In some embodiments, the processing device 140 can be connected to a computer-readable storage medium (e.g., Figure 1 The processing device 140 may include an acquisition module 710 and a determination module 720.

[0124] The acquisition module 710 may be used to acquire output information of an optical sensor of a detector microblock. More descriptions on acquiring output information may be found elsewhere in this specification (eg, step 802 and related descriptions thereof).

[0125] The determination module 720 may be configured to determine location information of a photon gamma interaction occurring in a crystal element of the detector microblock based on the output information of the optical sensor. The location information may indicate a location of a photon gamma interaction occurring in a crystal element of the detector microblock. More descriptions of determining the location information of a photon gamma interaction may be found elsewhere in this specification (e.g., step 804 and its related description).

[0126] It should be noted that the above description of the processing device 140 is for illustrative purposes only and is not intended to limit the scope of this specification. For those of ordinary skill in the art, various changes and modifications can be made according to the description of this specification. However, these changes and modifications do not depart from the scope of this specification. For example, the processing device 140 may include a storage module for storing data generated by the above modules of the processing device 140. For another example, one or more modules may be integrated into a single module to perform its functions.

[0127] Figure 8 FIG. 8 is a flow chart of an exemplary process 800 for determining the location of a photon gamma interaction in a detector microblock according to some embodiments of the present specification. The process 800 may be Figure 1 The process 800 is implemented in the imaging system 100 shown in the figure. For example, the process 800 may be stored in the storage device 150 in the form of instructions (such as an application program) and called and / or executed by the processing device 140.

[0128] In step 802 , the processing device 140 (eg, the acquisition module 710 ) may acquire output information of an optical sensor of a detector microblock.

[0129] The detector microblock can be used to detect annihilation photons generated by annihilation events during ECT scanning of an object. In some embodiments, the detector microblock can include one or more detector units arranged side by side along the second direction. Each of the one or more detector units can include a plurality of crystal elements and an optical sensor array. The crystal elements can be arranged into crystal element columns along a first direction perpendicular to the second direction, and arranged into crystal element rows along the second direction. The optical sensor array can include optical sensors arranged along the first direction. For more description of the detector microblock, please refer to other contents in this specification, such as Figure 5A-5D and related instructions.

[0130] When a photon gamma interaction occurs in a detector microblock coupled to an optical sensor, it may excite one or more optical photons, which in turn may be detected by at least one optical sensor of the detector microblock. In response to detecting the optical photons, at least one optical sensor may output an electrical signal. The electrical signal is also referred to as output information in this specification. The output information may include an energy value detected by each of the at least one optical sensor. Alternatively, the output information may also be a parameter other than the energy value, such as signal intensity, pulse width.

[0131] Taking the detector microblock 300 as an example, when a photon gamma interaction occurs in the detector microblock 300 coupled to the optical sensors 321a, 321b, 341a, and 341b, one or more optical photons may be excited by the photon gamma interaction and detected by at least one of the optical sensors 321a, 321b, 341a, and 341b. Correspondingly, output information may be output by at least one of the optical sensors 321a, 321b, 341a, and 341b.

[0132] In some embodiments, processing device 140 may obtain output information from an imaging device (eg, imaging device 110 ) or a storage device storing output information (eg, storage device 150 , a database, or an external storage device).

[0133] In step 804 , the processing device 140 (eg, the determination module 720 ) may determine position information of a photon gamma interaction occurring in a crystal element of the detector microblock based on the output information of the optical sensor.

[0134] The position information may indicate the position of the photon gamma interaction occurring in the crystal element of the detector microblock. For example, the position information may include a target crystal element column, a target crystal element, first position information of the photon gamma interaction along a first direction, second position information of the photon gamma interaction along a second direction, and third position information of the photon gamma interaction along a third direction perpendicular to the first direction and the second direction. The target crystal element column refers to the crystal element column where the photon gamma interaction occurs, and the target crystal element refers to the crystal element where the photon gamma interaction occurs.

[0135] In some embodiments, the processing device 140 may determine the target crystal element column based on the output information of the optical sensor. Taking the detector microblock 300 as an example, when the optical sensors 321a and 321b detect energy, and the optical sensors 341a and 341b do not detect energy, or the energy detected by the optical sensors 341a and 341b is less than the energy threshold, the processing device 140 may determine the crystal element column 350a as the target crystal element column. The energy threshold may reflect the minimum energy at which the optical sensor can detect the photon gamma interaction. In some embodiments, the energy threshold may be determined according to the system default setting, or manually set by the user. For another example, when the optical sensors 321a, 321b, 341a, and 341b detect energy, the processing device 140 may determine the crystal element column 350b or the crystal element column including the crystal element 331a and the crystal element 331c as the target crystal element column.

[0136] In some embodiments, processing device 140 may determine the target crystal element based on the output information of the optical sensor and the target crystal element column. For example, after determining that crystal element column 350a is the target crystal element, the target crystal element may be determined by comparing the output information corresponding to optical sensors 321a and 321b. For example, if the energy value in the output information corresponding to optical sensor 321a is greater than the energy value in the output information corresponding to optical sensor 321b, crystal element 311a may be determined as the target crystal element.

[0137] In some embodiments, the processing device 140 may determine the first position information and the second position information based on the output information of the optical sensor. For example, the center of gravity method may be used to determine the first position information and the second position information where the photon gamma interaction occurs in the detector microblock 300. The center of gravity method may be expressed by formula (1):

[0138]

[0139] Wherein, X refers to the abscissa of the position where the photon gamma ray interaction occurs in the detector microblock 300 (i.e., the second position information); Y refers to the ordinate of the position where the photon gamma ray interaction occurs in the detector microblock 300 (i.e., the first position information); A refers to the energy detected by the optical sensor 341b corresponding to the crystal element 331c and the crystal element 331d; B refers to the energy detected by the optical sensor 321b corresponding to the crystal element 311c and the crystal element 311d; C refers to the energy detected by the optical sensor 341a corresponding to the crystal element 331a and the crystal element 331b; D refers to the energy detected by the optical sensor 321a corresponding to the crystal element 311a and the crystal element 311b. In some embodiments, a coordinate system corresponding to (X, Y) is established with the intersection of the crystal elements 331a, 331c, 311b, and 311d as the coordinate origin, the second direction as the abscissa axis, and the first direction as the ordinate axis.

[0140] In some embodiments, the processing device 140 may determine the target crystal element column and / or the target crystal element according to the first position information and the second position information. For example, the processing device 140 may determine the target crystal element column and / or the target crystal element according to the abscissa X and ordinate Y of the position where the photon gamma interaction occurs in the detector microblock 300.

[0141] In some embodiments, the third position information of the photon gamma interaction can be determined based on the output information of the optical sensor, the first position information, and the second position information. The third position information refers to the depth of the photon gamma interaction in the target crystal element along the third direction (i.e., DOI). For example, the DOI may include the distance between the photon gamma interaction and the first end S1 of the target crystal element along the extension direction of the target crystal element (i.e., the third direction).

[0142] In some embodiments, after determining the first position information and the second position information, the processing device 140 may determine the target crystal element, the target crystal element column, the target optical sensor in the optical sensor corresponding to the target crystal element, and the auxiliary optical sensor other than the target optical sensor in the optical sensor corresponding to the target crystal element column. Then, the processing device 140 may determine the DOI based on the first output information detected by the target optical sensor and the second output information detected by the auxiliary optical sensor. For example, the DOI may be determined based on the ratio of the energy detected by the target optical sensor to the energy detected by the auxiliary optical sensor. For example, the DOId of the photon gamma interaction within the target crystal element may be determined based on formula (2):

[0143] d=LUT[E1 / (E1+E2)],(2)

[0144] Wherein, E1 represents the energy detected by the target optical sensor; E2 represents the energy detected by the auxiliary optical sensor; and LUT is an operation of looking up a lookup table. The lookup table may refer to a table that records the relationship between the depth of photon gamma interaction in the target crystal element and the E1 / (E1+E2) value. In some embodiments, the lookup table may be determined based on multiple depths of photon gamma interaction and their corresponding E1 / (E1+E2) values. The lookup table may be stored in a storage device (e.g., storage device 150) of the imaging system 100. When determining the DOI, the processing device 140 may call the lookup table from the storage device and determine the DOId of the photon gamma interaction by searching the lookup table.

[0145] In some embodiments, the processing device 140 may generate an ECT image based on the DOIs of the photon gamma interaction. For example, the processing device 140 may generate lines of response (LORs) based on the DOIs of the photon gamma interaction, and generate an ECT image by processing the LORs. By generating LORs based on the DOIs of the photon gamma interaction, the accuracy of the LORs can be improved, thereby improving the spatial resolution and the temporal resolution, and thus improving the accuracy of the PET image.

[0146] According to some embodiments of the present specification, by introducing a special design structure of a U-shaped detector microblock, the position information of the photon gamma interaction occurring in the crystal element of the detector microblock can be determined based on the output information of the optical sensor, thereby improving the resolution (e.g., spatial resolution) of the output information, thereby improving the accuracy of the ECT image generated based on the output information. In addition, by using a U-shaped detector microblock, the amount of data that needs to be processed (e.g., output information) can be reduced, thereby improving data processing efficiency.

[0147] Fig. 9 is a flowchart of an exemplary process 900 of ECT according to some embodiments of this specification. The process 900 can be Figure 1 The process 900 is implemented in the imaging system 100 shown in the figure. For example, the process 900 may be stored in the storage device 150 in the form of instructions (such as an application program) and called and / or executed by the processing device 140.

[0148] In step 902 , the processing device 140 (eg, the acquisition module 710 ) may acquire output information of optical sensors of a plurality of detector micro-blocks of one or more detector blocks in a detector.

[0149] In some embodiments, when an imaging device (e.g., imaging device 110) is used to perform ECT scanning on an object, optical sensors of multiple detector micro-blocks of one or more detector blocks in a detector of the imaging device may collect output information. For each optical sensor, the method of obtaining the output information may be similar to the method of obtaining the output information in step 802, and will not be repeated here.

[0150] In step 904 , the processing device 140 (eg, the partitioning module 730 ) may partition the output information into a first subset and a second subset.

[0151] The first subset may correspond to optical sensors of one or more first detector microblocks, and the second subset may correspond to optical sensors of one or more second detector microblocks. In some embodiments, the plurality of detector microblocks may include one or more first detector microblocks and one or more second detector microblocks. The short sides of the crystal elements in the one or more first detector microblocks may be perpendicular to the short sides of the crystal elements in the one or more second detector microblocks. For example, the short sides of the crystal elements in one or more first detector microblocks in the plurality of detector microblocks may be parallel to the row direction of the block array, and the short sides of the crystal elements in one or more second detector microblocks in the plurality of detector microblocks may be parallel to the column direction of the block array. For more description about the one or more first detector microblocks and the one or more second detector microblocks, please refer to other contents in this specification, such as Figure 6C-6F and related instructions.

[0152] For example, the processing device 140 may divide the output information into a first subset and a second subset based on whether the corresponding optical sensor belongs to the first detector unit or the second detector unit.

[0153] In step 906 , the processing device 140 (eg, the generation module 740 ) may generate a first ECT image based on the first subset and a second ECT image based on the second subset.

[0154] In some embodiments, the processing device 140 may generate a first ECT image by reconstructing the first subset using a first imaging reconstruction algorithm. Exemplary imaging reconstruction algorithms may include an analytical method (e.g., a filtered back projection algorithm), an iterative method, a maximum likelihood expectation maximization (MLEM) algorithm, an ordered subset expectation maximization (OSEM) algorithm, etc., or any combination thereof. Similarly, a second ECT image may be generated by reconstructing the second subset using a second imaging reconstruction algorithm. The second imaging reconstruction algorithm may be the same as or different from the first imaging reconstruction algorithm.

[0155] Since the short sides of the crystal elements of one or more first detector microblocks in the plurality of detector microblocks are perpendicular to the short sides of the crystal elements of one or more second detector microblocks in the plurality of detector microblocks, the full width at half maximum (FWHM) of the crystal elements of the first detector microblocks can be different from the full width at half maximum of the crystal elements of the second detector microblocks. Therefore, the resolution of the first subset can be different from the resolution of the second subset. Resolution refers to temporal resolution, spatial resolution, effective depth resolution, etc., or any combination thereof. For example, see Fig.6D Since the FWHM of the crystal element of the detector micro-block 300c along the first direction is greater than the FWHM of the crystal element of the detector micro-block 300d along the first direction, the resolution (e.g., spatial resolution) of the first subset along the first direction may be greater than the resolution of the second subset along the first direction. Correspondingly, the first image resolution of the first ECT image along the first direction may be greater than the second image resolution of the second ECT image along the first direction. Similarly, the first image resolution of the first ECT image along the second direction may be less than the second image resolution of the second ECT image along the second direction.

[0156] In some embodiments, the processing device 140 may generate a third ECT image based on the first subset and the second subset. For example, the third ECT image may be generated by reconstructing the first subset and the second subset using a third imaging reconstruction algorithm. The third imaging reconstruction algorithm may be the same as or different from the first imaging reconstruction algorithm and / or the second imaging reconstruction algorithm.

[0157] Since the third ECT image is generated based on the first subset and the second subset, a third image resolution of the third ECT image along the first direction may be greater than a second image resolution of the second ECT image along the first direction, and less than a first image resolution of the first ECT image along the first direction. A third image resolution of the third ECT image along the second direction may be less than a second image resolution of the second ECT image along the second direction, and greater than a first image resolution of the first ECT image along the second direction.

[0158] According to some embodiments of the present specification, a first ECT image, a second ECT image, and a third ECT image with different image resolutions can be generated based on the first subset and the second subset. Therefore, the system and method provided in the present specification can meet different imaging requirements and have a wider range of applications.

[0159] For example, by arranging the detector microblocks into a checkerboard structure, the imaging effect (e.g., resolution) of the detector can be improved. Fig.10As shown, the image in box 1002 has a higher image resolution than the image in box 1004, wherein the image in box 1002 is obtained using a detector with a checkerboard structure, while the image in box 1004 is obtained using a traditional detector.

[0160] It should be noted that the description of processes 800 and 900 is provided for the purpose of illustration, not for limiting the scope of this specification. For those skilled in the art, various changes and modifications can be made according to the teachings of this specification. For example, processes 800 and 900 can be completed by one or more additional operations not described and / or by one or more operations not discussed. In addition, the order of operations of processes 800 and 900 is not intended to be limiting. However, these changes and modifications shall not deviate from the scope of protection of this specification.

[0161] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those skilled in the art may make various modifications, improvements and corrections to this specification. Such modifications, improvements and corrections are suggested in this specification, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of this specification.

[0162] At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

[0163] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this specification, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0164] Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0165] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Correspondingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0166] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this specification are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the contents of this specification, documents that limit the broadest scope of the claims of this specification (currently or later attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and / or use of terms in this specification shall prevail.

[0167] Finally, it should be understood that the embodiments described in this specification are only used to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as an example and not a limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Correspondingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

Claims

1. A detector microblock for transmitting computed tomography, comprising: Detector units are arranged side by side along the second direction, wherein each of the detector units comprises: crystal elements, the crystal elements being arranged in crystal element rows along the second direction and in crystal element columns along a first direction perpendicular to the second direction, each of the crystal elements comprising a first end and a second end and extending from the first end to the second end along a third direction perpendicular to the first direction and the second direction; and An optical sensor array, the optical sensor array comprising optical sensors arranged along the first direction; wherein, In each of the crystal element rows, the first end of the crystal element is optically coupled to an optical sensor in the optical sensor array, and An optical bridge is provided at the second end of the crystal element in each of the crystal element columns.

2. The detector microblock according to claim 1, characterized in that: For each of the crystal element columns in each of the detector units, An optical separator is arranged between each pair of adjacent crystal elements in the crystal element column; The optical separator extends from the first ends of a corresponding pair of adjacent crystal elements in each pair of adjacent crystal elements without reaching the second ends of the corresponding pair of adjacent crystal elements.

3. The detector microblock according to claim 1, characterized in that: For each of the detector units, An optical separator is arranged between each pair of adjacent crystal element columns in the detector unit; The optical separator extends from a first end of the crystal element in a corresponding pair of adjacent crystal element columns in each pair of adjacent crystal element columns to a second end of the crystal element in the corresponding pair of adjacent crystal element columns.

4. The detector microblock according to claim 1, characterized in that: For each crystal element column of each of the detector units, An optical separator is disposed between each pair of adjacent crystal elements in the crystal element column, and the optical separator extends from a first end of a corresponding pair of adjacent crystal elements in each pair of adjacent crystal elements to a second end of the corresponding pair of adjacent crystal elements, and The optical bridge includes an optical propagation medium covering the second ends of the crystal elements in the crystal element column.

5. The detector microblock according to claim 1, characterized in that: An optical separator is arranged between each pair of adjacent detector units in the detector microblock; The optical separator extends from the second end of the crystal element in a corresponding pair of adjacent detector units in each pair of adjacent detector units without reaching the first end of the crystal element in the corresponding pair of adjacent detector units.

6. The detector microblock according to claim 1, characterized in that: For each of the detector units, In each of the crystal element columns of the detector unit, two of the crystal elements are arranged along the first direction, and In each of the crystal element rows of the detector unit, two of the crystal elements are arranged along the second direction.

7. The detector microblock according to claim 1, characterized in that: Each of the crystal elements includes a long side along the first direction and a short side along the second direction, and the length of the long side along the first direction is greater than the length of the short side along the second direction.

8. The detector microblock according to claim 1, characterized in that: The crystal element array and the detector microblock have a U-shaped structure or an inverted U-shaped structure respectively.

9. The detector microblock according to claim 1, characterized in that: The second ends of the crystal elements in each of the crystal element columns are integrated into an integral piece to serve as the optical bridge.

10. A detector block for transmitting computed tomography, characterized in that The method comprises a plurality of detector micro-blocks as claimed in claim 7, wherein the plurality of detector micro-blocks are arranged in a block array.

11. The detector block according to claim 10, characterized in that: A short side of the crystal element of one or more first detector micro-blocks among the plurality of detector micro-blocks is perpendicular to a short side of the crystal element of one or more second detector micro-blocks among the plurality of detector micro-blocks.

12. The detector block according to claim 11, characterized in that: Each pair of adjacent detector microblocks in the plurality of detector microblocks includes one of the first detector microblocks and one of the second detector microblocks to form a checkerboard structure, wherein: The detector microblocks in each row of the detector blocks parallel to the diagonal direction of the block array have the same orientation, and / or The orientations of the detector micro-blocks in adjacent rows parallel to the diagonal direction are perpendicular to each other.

13. A detector microblock for transmitting computed tomography, characterized in that: include: One or more detector units, each detector unit comprising: Crystal elements, the crystal elements are arranged into crystal element rows along a second direction and into crystal element columns along a first direction perpendicular to the second direction, the crystal element columns are configured into a U-shaped structure or an inverted U-shaped structure; An optical sensor array comprises optical sensors arranged along the first direction; wherein, in each of the crystal element rows, the crystal elements are optically coupled with the optical sensors in the optical sensor array.

14. The detector microblock according to claim 13, characterized in that: The detector unit further comprises an optical separator and an optical bridge, wherein the optical separator and the optical bridge are arranged in the U-shaped structure or the inverted U-shaped structure of the crystal element column.

15. The detector microblock according to claim 13, characterized in that: The detector microblock has a U-shaped structure or an inverted U-shaped structure.

16. The detector microblock according to claim 13, characterized in that: Each of the crystal elements includes a long side along the first direction and a short side along the second direction, and the length of the long side along the first direction is greater than the length of the short side along the second direction.

17. A detector block for transmitting computed tomography, characterized in that The method comprises a plurality of detector micro-blocks as claimed in claim 16, wherein the plurality of detector micro-blocks are arranged in a checkerboard structure in a block array manner.

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