A method, device and medium for optimizing detectors in a PET system

Abstract

The present invention provides a method, device, and medium for optimizing detectors in a PET system, including: generating a background radiation energy spectrum of the detector based on background radiation from the detector; obtaining actual radiation from the PET system and obtaining an energy window range based on the background radiation energy spectrum and the actual radiation; within the energy window range, calculating and obtaining the actual single event count rate of the detector corresponding to any of multiple detection thresholds within a unit detection time based on the actual radiation, obtaining a detection threshold with the maximum corresponding actual single event count rate, and setting it as the detector's processing threshold, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold. Using the above technical solution, the detector's background radioactivity can be used to adjust the detection threshold, avoiding the additional radiation risks and radiation source management requirements of external radiation sources, and enabling detector processing threshold optimization for radiation of different energies.

Description

Technical Field

[0001] The present invention relates to the field of nuclear medicine imaging technology, and in particular to a detector optimization method, device and medium in a PET system. Background Art

[0002] Positron emission tomography (PET) is a nuclear medicine imaging technique widely used in clinical tumor detection, localization, and clinical pathology research. Its principle is to combine a radionuclide with a specific lifetime (such as 18F-FDG) that decays with positrons with a specific lifetime with a biological metabolite (such as glucose, nucleic acids, and proteins) as a carrier, forming a specific tracer. This is then introduced into the human body and participates in metabolic processes. The positron annihilates with surrounding negative electrons, instantly emitting two gamma photons of equal energy and opposite directions. These photons are captured by the PET imaging system's detector. Based on the corresponding detection position, energy, and time-of-flight information, a 3D image reconstruction algorithm is used to reconstruct the tracer's concentration distribution in the human body. Because the tracer's concentration distribution is related to metabolic intensity, it indirectly reflects the body's metabolic intensity distribution, providing physicians with auxiliary medical diagnostic information.

[0003] The detectors used in current commercial PET systems are mostly based on scintillator crystals. Common scintillators include bismuth germanium oxide (BGO), lutetium silicate (LSO), and lutetium yttrium silicate (LYSO). When gamma photons strike a scintillator crystal, they stimulate visible fluorescence, which generates an electrical signal on a photomultiplier tube (PMT) or silicon photomultiplier (SiPM), which is then amplified and output.

[0004] However, when a PET system scans, a large amount of radiation is scattered as it passes through the material being scanned, generating a large amount of low-energy radiation. If the detector also collects and processes the photon signals of these low-energy radiation, it will cause blockage in the detector's front-end electronics, increase the system's dead time, and lose a large number of photon signals. Therefore, it is necessary to optimize the detector. Specifically, a threshold is set for the photon signals detected by the detector. Only when the energy intensity of the photon signal exceeds the threshold does the detector process the photon signal and convert it into an electrical signal, thereby reducing the system's dead time and improving scanning efficiency. Because PET systems primarily detect gamma photons with an energy of 511 keV, existing detector optimization methods typically use external radiation sources such as F-18, Na-22, and Ge-68. This introduces additional radiation risks and radiation source management requirements when optimizing the detector. Summary of the Invention

[0005] In order to overcome the above technical defects, the purpose of the present invention is to provide a method, device and medium for optimizing the detector in a PET system, which are used to determine the energy threshold of the photon signal that can be processed by the detector to improve the scanning efficiency.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for optimizing a detector in a PET system comprises the following steps:

[0008] Preset multiple detection thresholds, obtain background radiation rays of the detector, and based on the background radiation rays, respectively calculate and obtain the background single event count rate corresponding to any one of the multiple detection thresholds within a unit detection time, and generate the background radiation energy spectrum of the detector;

[0009] Acquire actual radiation rays from the PET system, and obtain an energy window range based on the background radiation energy spectrum and the actual radiation rays;

[0010] Within the energy window, based on the actual radiation rays, the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within the unit detection time is calculated and obtained respectively, and the detection threshold with the largest corresponding actual single event count rate is obtained and set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0011] Preferably, generating the background radiation energy spectrum of the detector includes:

[0012] Among the multiple detection thresholds, a detection threshold corresponding to the maximum background single event count rate is obtained as the preset threshold;

[0013] According to a preset threshold, based on background radiation, background coincidence event information of the detector within a unit detection time is obtained, where the background coincidence event information includes a first correspondence between a background coincidence event count rate and a background coincidence event energy;

[0014] The background radiation energy spectrum of the detector is generated according to the background coincidence event information.

[0015] Preferably, obtaining an energy window range according to the background radiation energy spectrum and the actual radiation rays includes:

[0016] Obtain the background characteristic peak of the background radiation energy spectrum and calculate the half-maximum width (FWHM) of the characteristic peak;

[0017] Get the actual radiation energy value E of the actual radiation ray c , and preset an energy window coefficient α, which represents the attenuation factor of the actual radiation, to obtain [E c -α×FWHM,E c +α×FWHM] is the energy window range.

[0018] Preferably, the background radiation energy spectrum is divided into a plurality of preset energy window ranges, and a second correspondence between the background single event count rate and the plurality of detection thresholds within any preset energy window range is calculated respectively, and a detection threshold having the maximum background single event count rate within any preset energy window range is obtained as the preset processing threshold corresponding to the preset energy window range;

[0019] Get the actual radiation energy value E of the actual radiation ray c , determine the actual radiation energy value E c The preset energy window range is located, and the preset processing threshold corresponding to the preset energy window range is obtained and set as the processing threshold of the detector.

[0020] Preferably, generating the background radiation energy spectrum of the detector according to the information of the background coincidence event includes:

[0021] generating an initial background radiation energy spectrum of the detector according to the background coincidence event information;

[0022] Perform energy calibration on the initial background radiation energy spectrum to obtain background energy correction parameters;

[0023] obtaining initial background single event information of the detector according to a second correspondence between the background single event count rate and a plurality of detection thresholds;

[0024] The initial background single event information is corrected according to the background energy correction parameter to obtain corrected background single event information, and a corrected background radiation energy spectrum is generated according to the corrected background single event information as the background radiation energy spectrum of the detector.

[0025] Preferably, performing energy calibration according to the original background radiation energy spectrum to obtain background energy correction parameters includes:

[0026] Get the background radiation energy value E of the background radiation ray a , obtain the initial background radiation energy spectrum E a The initial characteristic peak, according to the background radiation energy E a and the position of the initial characteristic peak to generate the basic energy correction parameters.

[0027] Preferably, the detector is a block matrix structure detector, and each block is composed of a plurality of scintillation crystal strips arranged in a matrix.

[0028] The present invention also provides a device for optimizing a detector in a PET system, comprising:

[0029] The background radiation analysis module presets multiple detection thresholds, obtains the background radiation rays of the detector, and calculates the background single event count rate corresponding to any one of the multiple detection thresholds within a unit detection time based on the background radiation rays, and generates the background radiation energy spectrum of the detector;

[0030] The energy window analysis module obtains the actual radiation rays of the PET system and calculates an energy window range based on the background radiation energy spectrum and the actual radiation rays;

[0031] The processing threshold analysis module calculates the actual single event count rate corresponding to any of the multiple detection thresholds within the energy window based on the actual radiation rays within the unit detection time, obtains the detection threshold with the largest corresponding actual single event count rate, and sets it as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0032] The present invention also provides a computer-readable storage medium for optimizing a detector in a PET system, wherein a computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the following steps are implemented:

[0033] Preset multiple detection thresholds, obtain background radiation rays of the detector, and based on the background radiation rays, respectively calculate and obtain the background single event count rate corresponding to any one of the multiple detection thresholds within a unit detection time, and generate the background radiation energy spectrum of the detector;

[0034] Acquire actual radiation rays from the PET system, and obtain an energy window range based on the background radiation energy spectrum and the actual radiation rays;

[0035] Within the energy window, based on the actual radiation rays, the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within the unit detection time is calculated and obtained respectively, and the detection threshold with the largest corresponding actual single event count rate is obtained and set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0036] Compared with the existing technology, the above technical solution has the following beneficial effects:

[0037] The detection threshold is adjusted by the background radioactivity of the detector, avoiding the additional radiation risk and radiation source management requirements of external radiation sources, which is simple and convenient. The detector processing threshold can be optimized for rays of different energies, not just the common 511keV rays. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic flow chart of a method for optimizing a detector in a PET system provided by the present invention;

[0039] Figure 2 A schematic diagram of the background single event count rate of the detector corresponding to any one of multiple detection thresholds within a unit detection time in a detector optimization method for a PET system provided by the present invention;

[0040] Figure 3 A schematic diagram of a background radiation energy spectrum provided by the present invention;

[0041] Figure 4 This is a schematic structural diagram of a detector optimization device in a PET system provided by the present invention. DETAILED DESCRIPTION

[0042] The advantages of the present invention are further described below with reference to the accompanying drawings and specific embodiments.

[0043] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0044] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0045] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining."

[0046] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0047] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal communication between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0048] In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention and have no specific meaning. Therefore, "module" and "component" can be used interchangeably.

[0049] See also Figure 1 As shown, the present invention discloses a method for optimizing a detector in a PET system, comprising the following steps:

[0050] S100, presetting multiple detection thresholds, obtaining background radiation rays of the detector, and calculating and obtaining the background single event count rate of the detector corresponding to any one of the multiple detection thresholds within a unit detection time based on the background radiation rays, and generating the background radiation energy spectrum of the detector.

[0051] Specifically, at this time, the actual radiation used for scanning in the PET system has not been emitted, and the detector only receives background radiation, that is, the radiation emitted by the detector's own crystals. Figure 2 As shown, multiple detection thresholds are preset, such as 200keV, 400keV, 600keV, 800keV, and 1000keV. The number of background single events received by the detector at any of the multiple detection thresholds within the unit detection time is calculated respectively to obtain the corresponding background single event count rate. For example, for a detection threshold of 400keV, within the unit detection time, the detector receives background radiation, detects photon signals with energy values greater than or equal to 400keV, and records the detected photon signal as a background single event. Since the detector has a dead time between receiving the photon signal and completing the count, in which the remaining photon signals cannot be processed, the number of photon signals that can be effectively recorded at this time is 55,000 times. Therefore, the background single event count rate corresponding to the detection threshold of 400keV within the unit detection time is determined to be 55,000. According to the same calculation method, the background single event count rates corresponding to the remaining detection thresholds can be obtained, and a relationship curve between the detection threshold and the background single event count rate can be formed.

[0052] S200: Acquire actual radiation rays from the PET system, and obtain an energy window range according to the background radiation energy spectrum and the actual radiation rays.

[0053] S300. Within the energy window, based on the actual radiation rays, calculate and obtain the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within the unit detection time, obtain the detection threshold with the largest corresponding actual single event count rate, and set it as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0054] Specifically, the PET system emits actual radiation and, based on the background radiation energy spectrum and the actual radiation, obtains an energy window range. For example, for actual radiation of 511 keV, assume an energy window range of [380 keV, 600 keV]. Based on this energy window range, the detection thresholds within this energy window range are determined to be 400 keV and 600 keV. The actual number of single events corresponding to each detection threshold within a unit detection time is calculated to obtain the corresponding actual single event count rate. For example, for a detection threshold of 400 keV, within a unit detection time, the detector receives the actual radiation emitted by the PET system and detects photon signals with energy values greater than or equal to 400 keV. Each detected photon signal is recorded as an actual single event. The number of actual single events is calculated, thereby determining the actual single event count rate corresponding to the detection threshold of 400 keV. The actual single event count rate corresponding to the detection threshold of 600 keV can be obtained using the same calculation method. A detection threshold corresponding to the maximum actual single event count rate is determined among the detection thresholds 400keV and 600keV. For example, if the actual single event count rate corresponding to 400keV is the largest, 400keV is set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to 400keV during subsequent scanning, that is, only photon signals with energy values greater than or equal to 400keV are recorded and converted into electrical signals.

[0055] Preferably, generating the background radiation energy spectrum of the detector includes:

[0056] Among the multiple detection thresholds, a detection threshold corresponding to the maximum background single event count rate is obtained as the preset threshold;

[0057] According to a preset threshold, based on background radiation, background coincidence event information of the detector within a unit detection time is obtained, where the background coincidence event information includes a first correspondence between a background coincidence event count rate and a background coincidence event energy;

[0058] The background radiation energy spectrum of the detector is generated according to the background coincidence event information.

[0059] Specifically, see Figure 2As shown, a detection threshold corresponding to the maximum background single event count rate is determined, for example, a detection threshold of 600keV, as a preset threshold. At this time, no actual radiation rays used for scanning in the PET system are emitted, and the detector only receives background radiation rays. Within a unit detection time, the detector receives background radiation rays and detects photon signals with energy values greater than or equal to 600keV. When the detector detects two photon signals in opposite directions within the same resolution time, it records a background coincidence event and records the energy value of the photon signal corresponding to the background coincidence event. This obtains a first correspondence between the background coincidence event count rate and the background coincidence event energy, and forms background coincidence event information.

[0060] Preferably, obtaining an energy window range according to the background radiation energy spectrum and the actual radiation rays includes:

[0061] Obtain the background characteristic peak of the background radiation energy spectrum and calculate the half-maximum width (FWHM) of the characteristic peak;

[0062] Get the actual radiation energy value E of the actual radiation ray c , and preset an energy window coefficient α, which represents the attenuation factor of the actual radiation, to obtain [E c -α×FWHM,E c +α×FWHM] is the energy window range.

[0063] Preferably, the background radiation energy spectrum is divided into a plurality of preset energy window ranges, and a second correspondence between the background single event count rate and the plurality of detection thresholds within any preset energy window range is calculated respectively, and a detection threshold having the maximum background single event count rate within any preset energy window range is obtained as the preset processing threshold corresponding to the preset energy window range;

[0064] Get the actual radiation energy value E of the actual radiation ray c , determine the actual radiation energy value E c The preset energy window range is located, and the preset processing threshold corresponding to the preset energy window range is obtained and set as the processing threshold of the detector.

[0065] Specifically, if Figure 3As shown, it can be seen from the background radiation energy spectrum of the detector that the background radiation emits gamma rays with energies of 202keV and 307keV, and also forms a superposition peak of beta particles and gamma rays near 598keV, thereby dividing multiple groups of preset energy segments, such as [0keV, 202keV], [202keV, 307keV], [307keV, 598keV], and [598keV, 1000keV]. The second corresponding relationship between the background single event count rate and multiple detection thresholds within any preset energy window range is calculated respectively, and the detection threshold with the largest background single event count rate corresponding to any preset energy window range is obtained as the preset processing threshold corresponding to the preset energy window range. The actual radiation energy value E of the actual radiation ray is obtained. c For example, for 511keV, it is determined that the preset energy window range in which 511keV is located is [307keV, 598keV], and thus the preset processing threshold corresponding to [307keV, 598keV] is set as the processing threshold of the detector.

[0066] Preferably, generating the background radiation energy spectrum of the detector according to the information of the background coincidence event includes:

[0067] generating an initial background radiation energy spectrum of the detector according to the background coincidence event information;

[0068] Perform energy calibration on the initial background radiation energy spectrum to obtain background energy correction parameters;

[0069] obtaining initial background single event information of the detector according to a second correspondence between the background single event count rate and a plurality of detection thresholds;

[0070] The initial background single event information is corrected according to the background energy correction parameter to obtain corrected background single event information, and a corrected background radiation energy spectrum is generated according to the corrected background single event information as the background radiation energy spectrum of the detector.

[0071] Preferably, performing energy calibration according to the original background radiation energy spectrum to obtain background energy correction parameters includes:

[0072] Get the background radiation energy value E of the background radiation ray a , obtain the initial background radiation energy spectrum E a The initial characteristic peak, according to the background radiation energy E a and the position of the initial characteristic peak to generate the basic energy correction parameters.

[0073] Preferably, the detector is a block matrix structure detector, and each block is composed of a plurality of scintillation crystal strips arranged in a matrix.

[0074] See also Figure 4As shown, the present invention also provides a device for optimizing a detector in a PET system, comprising:

[0075] The background radiation analysis module presets multiple detection thresholds, obtains the background radiation rays of the detector, and calculates the background single event count rate corresponding to any one of the multiple detection thresholds within a unit detection time based on the background radiation rays, and generates the background radiation energy spectrum of the detector;

[0076] The energy window analysis module obtains the actual radiation rays of the PET system and calculates an energy window range based on the background radiation energy spectrum and the actual radiation rays;

[0077] The processing threshold analysis module calculates the actual single event count rate corresponding to any of the multiple detection thresholds within the energy window based on the actual radiation rays within the unit detection time, obtains the detection threshold with the largest corresponding actual single event count rate, and sets it as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0078] The present invention also provides a computer-readable storage medium for optimizing a detector in a PET system, wherein a computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the following steps are implemented:

[0079] Preset multiple detection thresholds, obtain background radiation rays of the detector, and based on the background radiation rays, respectively calculate and obtain the background single event count rate corresponding to any one of the multiple detection thresholds within a unit detection time, and generate the background radiation energy spectrum of the detector;

[0080] Acquire actual radiation rays from the PET system, and obtain an energy window range based on the background radiation energy spectrum and the actual radiation rays;

[0081] Within the energy window, based on the actual radiation rays, the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within the unit detection time is calculated and obtained respectively, and the detection threshold with the largest corresponding actual single event count rate is obtained and set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold.

[0082] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for optimizing a detector in a PET system, characterized in that: The steps include: Presetting multiple detection thresholds, obtaining background radiation rays of the detector, and calculating and obtaining the background single event count rate of the detector corresponding to any one of the multiple detection thresholds within a unit detection time based on the background radiation rays, and generating a background radiation energy spectrum of the detector; Acquire actual radiation rays from the PET system, and acquire an energy window range according to the background radiation energy spectrum and the actual radiation rays; Within the energy window, based on the actual radiation, the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within a unit detection time is calculated and obtained, and a detection threshold with the largest corresponding actual single event count rate is obtained and set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold, wherein The obtaining of an energy window range according to the background radiation energy spectrum and the actual radiation rays includes: Obtaining a background characteristic peak of the background radiation energy spectrum, and calculating the half-maximum width (FWHM) of the characteristic peak; Get the actual radiation energy value E of the actual radiation ray c , and preset an energy window coefficient α, which represents the attenuation factor of the actual radiation, to obtain [E c -α×FWHM,E c +α×FWHM] is the energy window range; And also includes: Dividing the background radiation energy spectrum into a plurality of preset energy window ranges, respectively calculating a second correspondence between the background single event count rate and the plurality of detection thresholds within any of the preset energy window ranges, and obtaining a detection threshold having the maximum background single event count rate within any of the preset energy window ranges as a preset processing threshold corresponding to the preset energy window range; Get the actual radiation energy value E of the actual radiation ray c , determine the actual radiation energy value E c The preset energy window range in which the detector is located is obtained, and the preset processing threshold corresponding to the preset energy window range is obtained and set as the processing threshold of the detector.

2. The detector optimization method according to claim 1, characterized in that: Generating the background radiation energy spectrum of the detector includes: Among the multiple detection thresholds, a detection threshold corresponding to the maximum background single event count rate is obtained as the preset threshold; According to the preset threshold, based on the background radiation, obtaining background coincidence event information of the detector within the unit detection time, the background coincidence event information including a first correspondence between a background coincidence event count rate and a background coincidence event energy; A background radiation energy spectrum of the detector is generated according to the background coincidence event information.

3. The detector optimization method according to claim 2, characterized in that: Generating the background radiation energy spectrum of the detector according to the information of the background coincidence event includes: generating an initial background radiation energy spectrum of the detector according to the background coincidence event information; Performing energy calibration on the initial background radiation energy spectrum to obtain background energy correction parameters; Obtaining initial background single event information of the detector according to a second correspondence between the background single event count rate and the plurality of detection thresholds; The initial background single event information is corrected according to the background energy correction parameter to obtain corrected background single event information, and a corrected background radiation energy spectrum is generated according to the corrected background single event information as the background radiation energy spectrum of the detector.

4. The detector optimization method according to claim 3, characterized in that: The performing energy calibration according to the initial background radiation energy spectrum to obtain background energy correction parameters includes: Obtain the background radiation energy value E of the background radiation ray a , obtain the initial background radiation energy spectrum E a The initial characteristic peak, according to the background radiation energy E a and the position of the initial characteristic peak to generate the background energy correction parameter.

5. The detector optimization method according to claim 1, characterized in that: include: The detector is a block matrix structure detector, and each block is composed of a plurality of scintillation crystal strips arranged in a matrix.

6. A detector optimization device in a PET system, characterized in that: include: A background radiation analysis module is configured to preset multiple detection thresholds, obtain background radiation rays from the detector, and based on the background radiation rays, respectively calculate and obtain the background single event count rate corresponding to each of the multiple detection thresholds within a unit detection time, and generate a background radiation energy spectrum of the detector; an energy window analysis module, which obtains actual radiation rays of the PET system and calculates an energy window range based on the background radiation energy spectrum and the actual radiation rays; The processing threshold analysis module calculates and obtains the actual single event count rate of the detector corresponding to any of the multiple detection thresholds within the energy window range based on the actual radiation rays, obtains the detection threshold with the largest corresponding actual single event count rate, and sets it as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold, wherein The obtaining of an energy window range according to the background radiation energy spectrum and the actual radiation rays includes: Obtaining a background characteristic peak of the background radiation energy spectrum, and calculating the half-maximum width (FWHM) of the characteristic peak; Get the actual radiation energy value E of the actual radiation ray c , and preset an energy window coefficient α, which represents the attenuation factor of the actual radiation, to obtain [E c -α×FWHM,E c +α×FWHM] is the energy window range; And also includes: Dividing the background radiation energy spectrum into a plurality of preset energy window ranges, respectively calculating a second correspondence between the background single event count rate and the plurality of detection thresholds within any of the preset energy window ranges, and obtaining a detection threshold having the maximum background single event count rate within any of the preset energy window ranges as a preset processing threshold corresponding to the preset energy window range; Get the actual radiation energy value E of the actual radiation ray c , determine the actual radiation energy value E c The preset energy window range in which the detector is located is obtained, and the preset processing threshold corresponding to the preset energy window range is obtained and set as the processing threshold of the detector.

7. A computer-readable storage medium for optimizing a detector in a PET system, having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the following steps are implemented: Presetting multiple detection thresholds, obtaining background radiation rays of the detector, and calculating and obtaining the background single event count rate of the detector corresponding to any one of the multiple detection thresholds within a unit detection time based on the background radiation rays, and generating a background radiation energy spectrum of the detector; Acquire actual radiation rays from the PET system, and acquire an energy window range according to the background radiation energy spectrum and the actual radiation rays; Within the energy window, based on the actual radiation, the actual single event count rate of the detector corresponding to any one of the multiple detection thresholds within a unit detection time is calculated and obtained, and a detection threshold with the largest corresponding actual single event count rate is obtained and set as the processing threshold of the detector, so that the detector only processes photon signals with energy values greater than or equal to the processing threshold, wherein The obtaining of an energy window range according to the background radiation energy spectrum and the actual radiation rays includes: Obtaining a background characteristic peak of the background radiation energy spectrum, and calculating the half-maximum width (FWHM) of the characteristic peak; Get the actual radiation energy value E of the actual radiation ray c , and preset an energy window coefficient α, which represents the attenuation factor of the actual radiation, to obtain [E c -α×FWHM,E c +α×FWHM] is the energy window range; And also includes: Dividing the background radiation energy spectrum into a plurality of preset energy window ranges, respectively calculating a second correspondence between the background single event count rate and the plurality of detection thresholds within any of the preset energy window ranges, and obtaining a detection threshold having the maximum background single event count rate within any of the preset energy window ranges as a preset processing threshold corresponding to the preset energy window range; Get the actual radiation energy value E of the actual radiation ray c , determine the actual radiation energy value E c The preset energy window range in which the detector is located is obtained, and the preset processing threshold corresponding to the preset energy window range is obtained and set as the processing threshold of the detector.

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