An array detector for encoding light splitting and a method for obtaining depth information thereof

Abstract

This invention belongs to the field of radiation detector technology and relates to an array detector for coded spectral dispersion and a method for acquiring response depth information. The array detector includes: a scintillator array composed of multiple microprobes, with a light-reflecting layer disposed between adjacent pixel scintillators; a photoelectric channel array optically coupled to the scintillator array for converting detected scintillating light into electrical signals; and a light guide block array optically coupled to the first end face of the scintillator array, with adjacent light guide channels separated by a light-reflecting layer. The light guide block array is used to partially distribute light emitted from one pixel scintillator and entering the corresponding light guide channel to an adjacent pixel scintillator crystal, so that the light signal generated by the same scintillating event can be received by at least two photoelectric devices. Its advantages include high energy measurement accuracy and accurate timing, high linearity of DOI correlation, and more accurate measurement.

Description

Technical Field

[0001] This invention relates to the field of radiation detector technology, and in particular to an array detector with encoded spectral dispersion and a method for acquiring reaction depth information. Background Technology

[0002] PET (Positron Emission Tomography) is an important clinical diagnostic imaging technique in the field of nuclear medicine. Its basic principle is to inject a tracer containing a positron-emitting radioactive nuclide into the body, and then detect the energy, time, and location information of the 511 keV gamma rays emitted in opposite directions when the positron annihilates. Finally, the location of the lesion is determined by statistically reconstructing the location of the annihilation event. It is a three-dimensional imaging technique with high sensitivity, high spatial resolution, good accuracy, and the ability to perform functional imaging. It is widely used in the diagnosis of tumors, cardiovascular diseases, and neurological diseases.

[0003] In PET imaging reconstruction, if the detector does not provide depth information, conventional reconstruction assumes that events in the same pixel crystal occur at a fixed location. When the actual location where an obliquely incident gamma photon reacts in the detector is inconsistent with this fixed location, the conventionally reconstructed Line of Response (LOR) will not match the actual state. This effect is called the Depth of Interaction (DOI) effect. Figure 1 This is a simplified diagram illustrating how this effect leads to positioning errors.

[0004] The response depth effect affects the accuracy of response line localization, fundamentally impacting the sharpness of reconstructed images. In PET systems, this effect is more pronounced the further away from the center of the field of view, resulting in poorer spatial resolution and a more blurred image at that location. Especially with the increasing trend of axial field of view in PET systems, the proportion of oblique incidence events is rising, further amplifying the impact of the depth effect on system imaging.

[0005] To address the impact of reaction depth effects on PET system performance, various designs have been developed at the detector end to acquire reaction depth information of incident gamma photons. Patent application CN103917898B employs a dual-layer or multi-layer scintillation crystal detector design; however, this design is difficult to assemble, and the depth information depends on the layer thickness of the scintillation crystal, making it difficult to obtain more accurate depth information. Patent application CN117687071A adds photoelectric channels at both ends of the scintillation crystal and calculates depth information based on the relative magnitudes of the light signals detected at both ends of the crystal. However, this approach doubles the electronic design complexity compared to conventional designs, leading to increased circuit cost and failure rate. Summary of the Invention

[0006] Technical problems to be solved In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an array detector with coded spectral dispersion and a method for acquiring depth information, which solves the technical problem that current PET detectors with depth recognition use complex crystal or dual-end photoelectric detection designs, resulting in high costs.

[0007] Technical solution To achieve the above objectives, the main technical solutions adopted by the present invention include: In a first aspect, the present invention provides an array detector for coded spectral splitting, comprising: an array of light guide blocks, an array of scintillators, and an array of photoelectric channels; The scintillator array is composed of multiple microprobes spliced ​​together. Each microprobe is composed of multiple pixel scintillator crystals. Each pixel scintillator crystal has a first end face and a second end face that are arranged opposite to each other. The pixel scintillator has a length direction and a width direction. A light reflection layer is provided between adjacent pixel scintillators to produce diffuse reflection of the emitted scintillator light. The photoelectric channel array includes multiple photoelectric devices, and the light guide channel array is optically coupled to the second end face of the scintillator array to convert the scintillator light emitted by the scintillator array into an electrical signal; The light guide block array includes multiple light guide channels, which are optically coupled to the first end face of the scintillator array. Each adjacent light guide channel is separated by a light reflection layer. The light emitted from one of the pixel scintillators and entering the corresponding light guide channel is partially distributed to another adjacent pixel scintillator crystal, so that the light signal generated by the same scintillator event can be received by at least two of the optoelectronic devices.

[0008] Optionally, the light guide block array is divided into a main body and an edge part. The light guide channel of the main body splits light along the long side of the pixel scintillation crystal, and the light guide channel of the edge part splits light along the short side of the pixel scintillation crystal.

[0009] Optionally, the optoelectronic device is a single-anode photomultiplier tube, a multi-anode position-sensitive photomultiplier tube, an avalanche photodiode, or a silicon photomultiplier tube.

[0010] Optionally, the material of the light-reflecting layer is a diffuse reflection coating, a high-reflectivity thin film, or a metal reflective layer.

[0011] Optionally, the material of the light guide channel is a material with high transparency to scintillation light.

[0012] Optionally, the optical guide channel is rectangular at the end face coupled to the scintillator array; The cross-section of the light guide channel is a portion of a curved surface or a polyhedron coated with a light-reflecting material.

[0013] Optionally, in the photoelectric channel array, every 2×2 photoelectric devices constitute a detection unit, corresponding to a micro probe.

[0014] In a second aspect, the present invention provides a method for acquiring response depth information using an array detector employing coded spectral dispersion as described in any one of the first aspects above, comprising the following steps: Step 1: Irradiate the array detector with a radiation source of known energy; Step 2: After the gamma event occurs in the array detector, the pixel scintillator crystal is excited in the corresponding scintillator array to generate scintillator photons; Step 3: The scintillation photons are emitted in all directions, and the photoelectric channel array in the array detector detects the scintillation photons to obtain the first electrical signal and the second electrical signal; Step 4: Determine the location and time information of the gamma event occurring in the array detector based on the first electrical signal; Step 5: Calculate the reaction depth information of the γ event in the main pixel scintillation crystal by using the ratio of the magnitude of the light signal in the main pixel scintillation crystal when the γ event occurs to the sum of the total effective light signals after spectral splitting.

[0015] Optionally, in step 5, the main pixel scintillation crystal is defined as: when a γ event occurs at any pixel scintillation crystal, that pixel scintillation crystal is the main pixel scintillation crystal.

[0016] Optionally, the location where the gamma event occurs includes the edge region and the center region of the array detector; When the γ event occurs in the edge region of the array detector, the main pixel scintillation crystal and an adjacent pixel scintillation crystal perform short-side beam splitting through the optical guide array; When the γ event is located in the central region of the array detector, the main pixel scintillator crystal and an adjacent pixel scintillator crystal perform long-side beam splitting through the optical guide array; Wherein, the edge region corresponds to the pixel scintillation crystal coupled to the edge portion of the light guide block array, and the center region corresponds to the pixel scintillation crystal coupled to the main body portion of the light guide block array. Beneficial effects

[0017] The beneficial effects of this invention are: A detector array with response depth information capability was designed. Through the coded beam splitting function of the end-face photoguide, the response depth information of a gamma event is converted into the range and proportion information of the light distribution. Then, the relevant light distribution information is read out through the related information of the photoelectric channel array, and the response depth information of the gamma event is then reconstructed. This scheme obtains the position, energy, time, and response depth information of the gamma event economically and reliably without increasing the difficulty of scintillation crystal fabrication or the number of circuit processing paths, providing a solid data foundation for eliminating the impact of the DOI effect on the system's spatial resolution. Furthermore, the beam splitting structure of this invention ensures that beam splitting always occurs only between two crystals, and visible light mainly propagates within these two crystals. Although the received light may enter different photoelectric channels according to the sensitive region, the luminous flux at the two main outputs of the beam splitting is larger than other beam splitting modes, resulting in high energy measurement accuracy, accurate timing, high DOI correlation linearity, and more accurate measurements. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the positioning error caused by the reaction depth effect in an embodiment of the present invention; Figure 2 This invention provides an array detector for coded beam splitting. Figure 3 This is a schematic diagram of the scintillator array distribution in the microprobe in an embodiment of the present invention; Figure 4 This is a schematic diagram of the matching between the optical guide and the crystal array in an embodiment of the present invention; Figure 5 This is a schematic diagram of the cross-section of the optical guide channel in an embodiment of the present invention; Figure 6 This is a schematic diagram of spectral dispersion after the occurrence of a γ event in an embodiment of the present invention; Figure 7 This is a flowchart of a method for acquiring reaction depth information using an array detector with coded spectral dispersion, provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of an array detector in an embodiment of the present invention, showing that the γ event occurs in the edge region of the array detector. Figure 9This is a schematic diagram of an array detector in an embodiment of the present invention, showing that the γ event occurs in the middle region of the array detector.

[0019] [Explanation of Labels in the Attached Image] 1: Optical guide array; 2: Scintillator array; 3: Photoelectric channel array; 101: First light guide block, 102: Second light guide block, 103: Third light guide block, 104: Fourth light guide block, 201: First pixel scintillation crystal, 202: Second pixel scintillation crystal, 203: Third pixel scintillation crystal, 204: Fourth pixel scintillation crystal, 205: Fifth pixel scintillation crystal, 206: Sixth pixel scintillation crystal, 207: Seventh pixel scintillation crystal, 208: Eighth scintillation crystal, 301: First SiPM, 302: Second SiPM, 303: Third SiPM, 304: Fourth SiPM, 305: Fifth SiPM, 306: Sixth SiPM, 307: Seventh SiPM. Detailed Implementation

[0020] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0021] Firstly, such as Figure 2 As shown, an embodiment of the present invention provides an array detector for coded beam splitting, comprising: a light guide block array 1, a scintillator array 2, and a photoelectric channel array 3.

[0022] The scintillator array 2 is composed of multiple microprobes. Each microprobe consists of multiple pixel scintillator crystals. Each pixel scintillator crystal has a first end face and a second end face that are arranged opposite to each other. The pixel scintillator has a length direction and a width direction. The thickness of each pixel scintillator crystal can be in the range of 5mm-40mm, and its length and width can be in the range of 0.5mm-10mm. The aspect ratio is in the range of 4:1 to 1:1. A light reflection layer is provided between adjacent pixel scintillators to generate diffuse reflection of the scintillator light.

[0023] like Figure 3 As shown, the scintillator array 2 uses 4×3 pixel scintillator crystals as the basic unit, which is called a microprobe. The number of microprobes can be expanded in integer multiples as needed.

[0024] The scintillation crystal material in the rectangular scintillator array 2 can be lutetium silicate (LSO), yttrium lutetium silicate (LYSO), cerium-doped gadolinium aluminum gallium garnet (GAGG(Ce)), sodium iodide (NaI), cesium iodide (CsI), bismuth germanate (BGO), lanthanum bromide (LaBr3), etc. The reflective material of the light reflective layer can be BaSO4, MgO, TiO2, etc., sprayed or coated, or it can be a thin film material with high reflectivity such as ESR, PET, etc. Alternatively, metal materials can be deposited onto the rough surface around the scintillation crystal pixel using evaporation, sputtering, etc., to achieve diffuse reflection of light.

[0025] The photoelectric channel array 3 includes multiple photoelectric devices. The light guide channel array is optically coupled to the second end face of the scintillator array 2 and is used to convert the detected scintillator light into an electrical signal, that is, to convert the light signal of each pixel scintillator crystal into an electrical signal for subsequent depth information processing.

[0026] Specifically, the photoelectric channel array 3 is used to detect the scintillation light emitted by each pixel scintillation crystal, including the luminous position and intensity of the γ event. The scintillation light of each photoelectric channel in the array is used as an output signal. This output signal is acquired by subsequent circuits and used as a data source to analyze the position information, energy information and time information of the incident γ event.

[0027] Among them, the optoelectronic devices that make up the optoelectronic channel array 3 are single anode photomultiplier tubes (PMTs), multi-anode position-sensitive photomultiplier tubes (PSPMTs), avalanche photodiodes (APDs), or silicon photomultiplier tubes (SiPMs).

[0028] In the photoelectric channel array 3, every 2×2 photoelectric devices constitute a detection unit, corresponding to a micro probe.

[0029] For the optoelectronic channel array 3 with PMT as the optoelectronic device, each optoelectronic channel refers to each PMT; for the optoelectronic channel array 3 with PSPMT as the optoelectronic device, each optoelectronic channel refers to the photoelectric area corresponding to each anode output; for the optoelectronic channel array 3 with APD as the optoelectronic device, each optoelectronic channel is each APD; for the optoelectronic channel array 3 with SiPM as the optoelectronic device, each optoelectronic channel is each SiPM.

[0030] The light guide block array 1 is a key part of the design, including multiple light guide channels. The light guide block array 1 is optically coupled to the first end face of the scintillator array 2 through a transparent material, and the coupled end face is rectangular. Each adjacent light guide channel is separated by a light reflection layer, which is used to perform beam splitting processing on the light emitted from the end face between two specified pixel scintillator crystals within a limited range.

[0031] Specifically, each light guide channel splits light between pixel scintillating crystals. The light guide block array 1 partially distributes the light emitted from one pixel scintillator and entering the corresponding light guide channel to another adjacent pixel scintillating crystal, so that the light signal generated by the same scintillating γ event can be received by at least two optoelectronic devices, and the light signal in one pixel scintillating crystal can be distributed in two pixel scintillating crystals and multiple optoelectronic channels. Figure 4 As shown, the light guide block array 1 is divided into a main body and an edge part. The light guide channel of the main body splits the light along the long side of the pixel scintillation crystal, and the light guide channel of the edge part splits the light along the short side of the pixel scintillation crystal.

[0032] like Figure 5 As shown, the cross-sectional surface of the optical guide channel is a portion of a curved surface coated with a reflective layer or a non-curved polyhedron.

[0033] The light guide channel is made of a material with high transparency to scintillation light, specifically including optical glass or highly transparent organic materials, and the optical surface of the light guide channel is polished. The reflective material of the light reflection layer can be sprayed or coated with materials such as BaSO4, MgO, and TiO2, or it can be a thin film material with high reflectivity such as ESR and PET. Alternatively, metal materials can be deposited onto the end face of the light guide channel using methods such as evaporation or sputtering to achieve the purpose of reflection.

[0034] Secondly, such as Figure 7 As shown, an embodiment of the present invention provides a method for acquiring reaction depth information using an array detector with coded spectral dispersion as described in the first aspect above, comprising the following steps: Step 1: Irradiate the array detector with a radiation source of known energy.

[0035] Step 2: When a γ event occurs in the array detector, the pixel scintillator crystal is excited in the corresponding scintillator array to generate scintillator photons.

[0036] Step 3: The scintillation photons are emitted in all directions, and the photoelectric channel array in the array detector detects the scintillation photons to obtain the first electrical signal and the second electrical signal.

[0037] Specifically, the scintillation photons are emitted in all directions, and the scintillation photons emitted towards the bottom are detected by the photoelectric channel corresponding to the pixel scintillation crystal in the array detector, and converted into a first electrical signal A. main The scintillation photons emitted towards the top are reflected by the photoconductor array in the array detector, and are detected by the photoelectric channel at the corresponding position, using other pixel scintillation crystals in the same photoconductor block as channels, thus generating a second electrical signal A. Share .

[0038] Step 4: Determine the location and time information of the gamma event in the array detector based on the first electrical signal.

[0039] Specifically, the largest first electrical signal A main The corresponding pixel scintillation crystal position is the location information p of the γ event occurring in the array detector. A main The time of signal occurrence is the time information t of the gamma event's response in the array detector.

[0040] Step 5: Calculate the depth of response (DOI) of the γ event in the main pixel scintillation crystal by using the ratio of the magnitude of the optical signal in the main pixel scintillation crystal when the γ event occurs to the sum of the total effective optical signals after spectral splitting.

[0041] In the array detector, the DOI information at the time of each event is characterized by the ratio of the magnitude of the optical signal in the scintillation crystal of the main pixel of the event to the sum of the total effective optical signals after beam splitting, in order to eliminate errors caused by interference such as optical crosstalk. Furthermore, the ratio of the signal amplitude output by each photoelectric channel in the depth information calculation is mainly determined by the relative position of the optical path composed of the scintillation crystal and the photoconductor block, which is also the core of the encoding beam splitting.

[0042] The main pixel scintillation crystal is defined as follows: if a γ event occurs at any pixel scintillation crystal, then that pixel scintillation crystal is the main pixel scintillation crystal. In other words, the main pixel scintillation crystal is the pixel scintillation crystal that receives the largest first electrical signal, and the position of this pixel scintillation crystal is the position information p of the γ event occurring in the array detector.

[0043] The gamma events include two types: those occurring in the edge region and the center region of the array detector; When the γ event occurs in the edge region of the array detector, the main pixel scintillation crystal and an adjacent pixel scintillation crystal perform short-side beam splitting through the optical guide array; When the γ event is located in the central region of the array detector, the main pixel scintillator crystal and an adjacent pixel scintillator crystal perform long-side beam splitting through the optical guide array; Wherein, the edge region corresponds to the pixel scintillation crystal coupled to the edge portion of the light guide block array, and the center region corresponds to the pixel scintillation crystal coupled to the main body portion of the light guide block array.

[0044] Furthermore, in the structural design of the array detector, the scintillator array and the photoelectric channel array are not in a one-to-one correspondence (i.e., not directly coupled one-to-one). Therefore, the light emitted by each pixel scintillator crystal will be superimposed and split in the photoelectric channel. What is actually measured is the output signal of the photoelectric channel, meaning the light received by the photoelectric channel may originate from a single pixel scintillator crystal (e.g., ...). Figure 6 (As shown in Class A distribution), it may also originate from the mixed light of multiple pixel scintillator crystals (such as...) Figure 6 (As shown in the Class B distribution). Therefore, when analyzing reaction depth information, the effects of superposition and spectral dispersion need to be considered, that is, the signal needs to be decoupled in subsequent data processing.

[0045] After obtaining the response depth information of gamma events in the array detector, considering the differences in the output energy information of gamma events at different depths, it is necessary to correct the gamma event energy information at different depths for the actual incident energy. Specifically, the detector is irradiated with a radiation source of known energy (such as Ge-68) to obtain the sum output energy information A of the scintillation crystals of each pixel at different depths d. sum The relative relationship between A and the incident ray energy E: sum =f(E, d). Similarly, the timing information t0 at different depths d and the relative relationship between the measured time t can be obtained: t0 = f(t, d).

[0046] The following example, using the measurement of the response depth information of an array detector with an 8×6 pixel scintillation crystal as a specific embodiment, further illustrates a method for acquiring response depth information using an array detector employing coded spectral splitting, comprising: The array detector, comprising 8×6 pixel scintillation crystals, uses LYSO material for the scintillation crystals, quartz glass for the photoconductor, and SiPM for the photoelectric channel. The relative relationship between the scintillation crystals and the photoconductor is shown in the figure below. Figure 4 As shown.

[0047] like Figure 8 As shown, when the γ event occurs in the edge region of the array detector, there are three types of beam splitting. The figure shows three SiPMs, a row of four pixel scintillation crystals, and beam splitting at the short side by a light guide block array between every two pixel scintillation crystals.

[0048] If the γ event occurs at the first pixel scintillator 201, its light signal is distributed between the first pixel scintillator 201 and the second pixel scintillator 202. At this time, the main pixel scintillator is the first pixel scintillator 201, and the adjacent pixel scintillator is the second pixel scintillator 202. The first SiPM 301 and the second SiPM 302 have signal amplitudes A1 and A2 respectively. The light emitted by the main pixel scintillator is output by the first SiPM 301. Since the light signal of the second pixel scintillator 202 is distributed between the first SiPM 301 and the second SiPM 302, that is, the light emitted by the adjacent pixel scintillator causes the first SiPM 301 to output an additional A2, the signal A1 output by the first SiPM 301 contains the signal output by the adjacent pixel scintillator, which is part of the light flux of the second pixel scintillator 202. Since the two SiPMs detect the same light flux of the second pixel scintillator 202, the signal amplitude of the main pixel scintillator incident on the first SiPM 301 should be corrected to A1-A2. The corresponding DOI information is then calculated according to the following formula: ; Wherein, A1 specifically represents the signal amplitude obtained by the photoelectric conversion device corresponding to the receiving X-ray crystal, which is usually the maximum signal amplitude, and A2 specifically represents the signal amplitude obtained by the photoelectric conversion device corresponding to the beam splitting from the light guide to other crystals.

[0049] If the γ event occurs at the second pixel scintillator 202, the light signal distribution of the γ event is also at the first pixel scintillator 201 and the second pixel scintillator 202. In this case, the main pixel scintillator is the second pixel scintillator 202, and the adjacent pixel scintillator is the first pixel scintillator 201. The first SiPM 301 and the second SiPM 302 output signal amplitudes A1 and A2, respectively. The light signal emitted by the main pixel scintillator is jointly output by the first SiPM 301 and the second SiPM 302, and the photosensitive surfaces of the first SiPM 301 and the second SiPM 302 are the same. That is to say, the light signal emitted by the main pixel scintillator is evenly distributed between the first SiPM 301 and the second SiPM 302. The corresponding DOI information is then calculated according to the following formula: ; If the γ event occurs at the third pixel scintillator crystal 203, the light signal of the γ event is distributed at the third pixel scintillator crystal 203 and the fourth pixel scintillator crystal 204. At this time, the main pixel scintillator is the third pixel scintillator crystal 203, and the adjacent pixel scintillator is the fourth pixel scintillator crystal 204. The second SiPM302 and the third SiPM303 have signal amplitude outputs A2 and A3 respectively. The light emission of the main pixel scintillator crystal is output by the second SiPM302, and the light signal distribution weights of the two pixel scintillator crystals are equal. Then, the corresponding DOI information is calculated according to the following formula: ; The processing method for γ events occurring at the fourth pixel scintillation crystal 204 is the same as that for γ events occurring at the third pixel scintillation crystal 203, except that the primary and secondary SiPMs are interchanged. The corresponding DOI information calculation formula is as follows: ; like Figure 9 As shown, when the γ event occurs in the central region of the array detector, there are two types of beam splitting. The figure shows four SiPMs, four pixel scintillation crystals, and beam splitting occurs along the long side of each pair of pixel scintillation crystals via an array of photoconductors.

[0050] If the gamma event occurs at the fifth pixel scintillator crystal 205, the light signal is distributed at both the fifth pixel scintillator crystal 205 and the sixth pixel scintillator crystal 206. In this case, the main pixel scintillator is the fifth pixel scintillator crystal 205, and the adjacent pixel scintillator is the sixth pixel scintillator crystal 206. The fourth SiPM304 and the fifth SiPM305 have signal amplitude outputs A4 and A5 respectively. The light emission from the main pixel scintillator crystal is output by the fourth SiPM304. According to the spectral splitting rules, a rough DOI information can be obtained. ; The DOI information of the γ event occurring at the sixth pixel scintillation crystal 206 is also processed symmetrically using the same encoding and beam splitting rules as the γ event occurring at the fifth pixel scintillation crystal 205. That is, its corresponding DOI information calculation formula is: ; If the gamma event occurs at the seventh pixel scintillator crystal 207, the light signal is distributed at both the seventh pixel scintillator crystal 207 and the eighth pixel scintillator crystal 208. In this case, the main pixel scintillator is the seventh pixel scintillator crystal 207, and the adjacent pixel scintillator is the eighth pixel scintillator crystal 208. All four SiPMs output signal amplitudes. The fourth SiPM 304, fifth SiPM 305, sixth SiPM 306, and seventh SiPM 307 output A4, A5, A6, and A7 respectively. The light emission from the main pixel scintillator crystal is output by the fifth SiPM 305 and the seventh SiPM 307. According to the spectral splitting rules, a rough DOI information can be obtained. ; The DOI information of the γ event occurring at the 8th pixel scintillation crystal 208 is also processed symmetrically using the same encoding and beam splitting rules as the γ event occurring at the 7th pixel scintillation crystal 207. That is, the corresponding DOI information calculation formula is: ; In this embodiment, since the SiPMs are closely arranged and the scintillation crystal is directly coupled to the SiPMs, the spectral ratio can be calculated based on the photosensitive area of ​​the SiPM facing the scintillation crystal. If there are gaps between the SiPMs, or if there is a light guide between the scintillation crystal and the SiPM, the spectral ratio coefficient needs to be allocated according to the effective photometric area of ​​each SiPM relative to the crystal array after the spectral design.

[0051] In practical use, the basic operating steps for the aforementioned coded beam splitter array detector with depth information readout function are as follows: Step 1: Based on the coding and spectral design rules, obtain the calculation formula for the response depth information of the pixel scintillation crystal at different spectral positions; Step 2: Using a ray source with known energy, obtain the corresponding relationship between the depth of the scintillation crystal of each pixel, the amplitude of the output signal, and the energy level; Step 3: After each γ event arrives, the position of the pixel blinking crystal where the γ event occurred is determined based on the centroid position of the output signal of the photoelectric channel; Step 4: Obtain the reaction depth information of the γ event based on the calculation formula of the reaction depth information of the corresponding pixel scintillation crystal; Step 5: Based on the reaction depth information and the output signal amplitude, obtain the energy magnitude of the incident γ event; Step 6: Based on the reaction depth information and output time information, obtain the accurate time information of the incident γ event.

[0052] After the reaction depth information is calculated by encoding and spectral analysis using the array detector described above, the reaction depth information can not only more accurately correct the position information output by the detector, but also calibrate the time information in turn, thereby obtaining better time information.

[0053] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0054] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An array detector that encodes light splitting, characterized by, include: Optical guide block array, scintillator array, and photoelectric channel array; The scintillator array is composed of multiple microprobes spliced ​​together. Each microprobe is composed of multiple pixel scintillator crystals. Each pixel scintillator crystal has a first end face and a second end face that are arranged opposite to each other. The pixel scintillator has a length direction and a width direction. A light reflection layer is provided between adjacent pixel scintillators to produce diffuse reflection of the emitted scintillator light. The photoelectric channel array includes multiple photoelectric devices, and the light guide channel array is optically coupled to the second end face of the scintillator array to convert the scintillator light emitted by the scintillator array into an electrical signal; The light guide block array includes multiple light guide channels, and the light guide block array is optically coupled to the first end face of the scintillator array. Each adjacent light guide channel is separated by a light reflection layer. This is used to partially distribute light emitted from one of the pixel scintillators and entering the corresponding light guide channel to another adjacent pixel scintillator crystal, so that the light signal generated by the same scintillator event can be received by at least two of the optoelectronic devices.

2. The array detector encoding the light splitting according to claim 1, characterized in that, The light guide block array is divided into a main body and an edge part. The light guide channel of the main body splits the light along the long side of the pixel scintillation crystal, and the light guide channel of the edge part splits the light along the short side of the pixel scintillation crystal.

3. The coded-aperture array detector of claim 2, wherein, The optoelectronic device is a single-anode photomultiplier tube, a multi-anode position-sensitive photomultiplier tube, an avalanche photodiode, or a silicon photomultiplier tube.

4. The coded-aperture array detector of claim 3, wherein, The material of the light-reflecting layer is a diffuse reflection coating, a high-reflectivity thin film, or a metal reflective layer.

5. The coded-aperture array detector of claim 4, wherein, The material of the light guide channel is a material with high transparency to scintillation light.

6. The coded-aperture array detector of claim 5, wherein, The optical guide channel is rectangular at the end face coupled to the scintillator array; The cross-section of the light guide channel is a portion of a curved surface or a polyhedron coated with a light-reflecting material.

7. The coded-aperture array detector of claim 6, wherein, In the photoelectric channel array, every 2×2 photoelectric devices constitute a detection unit, corresponding to a micro probe.

8. A method for acquiring reaction depth information using an array detector with coded spectral dispersion as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step 1: Irradiate the array detector with a radiation source of known energy; Step 2: After the gamma event occurs in the array detector, the pixel scintillator crystal is excited in the corresponding scintillator array to generate scintillator photons; Step 3: The scintillation photons are emitted in all directions, and the photoelectric channel array in the array detector detects the scintillation photons to obtain the first electrical signal and the second electrical signal; Step 4: Determine the location and time information of the gamma event occurring in the array detector based on the first electrical signal; Step 5: Calculate the reaction depth information of the γ event in the main pixel scintillation crystal by using the ratio of the magnitude of the light signal in the main pixel scintillation crystal when the γ event occurs to the sum of the total effective light signals after spectral splitting.

9. The method for acquiring reaction depth information using an array detector employing coded spectral dispersion according to claim 8, characterized in that, In step 5, the main pixel scintillation crystal is defined as follows: when a γ event occurs at any pixel scintillation crystal, that pixel scintillation crystal is the main pixel scintillation crystal.

10. The method for acquiring reaction depth information using an array detector employing coded spectral dispersion according to claim 9, characterized in that, The location where the γ event occurs includes the edge region and the center region of the array detector; When the γ event occurs in the edge region of the array detector, the main pixel scintillation crystal and an adjacent pixel scintillation crystal perform short-side beam splitting through the optical guide array; When the γ event is located in the central region of the array detector, the main pixel scintillator crystal and an adjacent pixel scintillator crystal perform long-side beam splitting through the optical guide array; Wherein, the edge region corresponds to the pixel scintillation crystal coupled to the edge portion of the light guide block array, and the center region corresponds to the pixel scintillation crystal coupled to the main body portion of the light guide block array.

Images