Energy selection method, depth-of-interaction acquisition method, apparatus and storage medium

Abstract

Disclosed are an energy selection method, a depth-of-interaction (DOI) acquisition method, an apparatus and a storage medium. The energy selection method comprises: acquiring nonlinear energy windows corresponding to different types of rays; and selecting the corresponding nonlinear energy windows on the basis of the different types of ray, and performing selection on energy at two ends of a double-end readout DOI detector, which energy is acquired on the basis of a target object, so as to acquire energy at the two ends of the double-ended readout DOI detector, which energy belongs to the nonlinear energy windows. On the basis of nonlinear energy windows, data of energy at two ends of a double-end readout DOI detector is retained, which data is within a numerical range of the nonlinear energy windows, and the other data is screened out, such that scattering events may be effectively removed, and more true events are retained, thereby improving the DOI resolution.

Description

Energy screening method, reaction depth acquisition method, device and storage medium

[0001] This application claims priority to Chinese patent application No. 202311773069.3 filed on December 21, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of signal sampling technology, and in particular to an energy screening method, a reaction depth acquisition method, a device, and a storage medium. Background Art

[0003] Positron emission tomography (PET) can be used for early detection of metabolic abnormalities in humans and preclinical research, which requires PET to have excellent spatial resolution and sensitivity. To improve the sensitivity and spatial resolution of PET scanners, the crystals in the detector should be as long as possible and as small as possible in cross-section to effectively increase the probability of gamma-ray interaction when they enter the crystal. The uncertainty of the depth at which gamma photons deposit within the crystal can cause parallax effects, which can reduce the spatial resolution of PET, especially for devices with small FOVs (fields of view) or non-annular structures. Therefore, depth of interaction (DOI) detectors capable of measuring DOI interactions are gaining increasing attention.

[0004] In traditional PET, gamma photon energy information is read out by a single-ended readout detector coupled to a silicon photomultiplier (SiPM) at one end. After determining an appropriate energy window, scintillation pulses within the energy window are retained, while scintillation pulses outside the window are discarded to eliminate scattering events. Among DOI detectors, the dual-ended readout DOI detector is the most commonly used and currently offers the best DOI resolution. In this design, two SiPMs are coupled to each end of the crystal to measure the optical signal. DOI information is obtained by calculating the ratio of the light output detected at one end to the sum of the light outputs detected at both ends. Furthermore, to obtain better DOI information, dual-ended readout DOI detectors require roughening of all four sides of the crystal. Consequently, in dual-ended readout DOI detectors, the energy of the gamma photon is read out by the detectors at both ends, splitting the photon energy into two. Due to the roughening of the crystal, the energy output at both ends varies with the location of the photon deposition.

[0005] Because a dual-end readout DOI detector determines the deposition depth of gamma photons by measuring the difference in energy output at the two ends of the crystal, the sum of the energy outputs at both ends varies with the deposition depth. Normally, the sum of the energy outputs at the two ends is greater when the photons are deposited at the two ends than when they are deposited in the middle. Consequently, if the energy spectra of adjacent DOI positions near the middle overlap, the overall energy sum distribution range approaches the energy sum distribution range at the two ends. However, if scattering occurs at the two ends, the energy sum approaches the energy sum distribution range at the middle. Therefore, when directly performing energy screening using the linear performance window method, selecting an energy window that is too small will filter out some true scintillation pulses, while selecting an energy window that is too large will retain too many scattered and superimposed scintillation pulses. This increases the energy error of the measured scintillation pulses, which in turn reduces the DOI resolution of the dual-end readout detector.

[0006] In view of this, there is an urgent need to provide a method that can better perform energy screening on dual-end readout DOI detectors to retain more true events and thus improve DOI resolution.

[0007] The contents of the background technology section are merely disclosed technologies known to the inventors and are not considered to represent the prior art in this field. Summary of the Invention

[0008] The present application aims to provide an energy screening method, a reaction depth acquisition method, a device, and a storage medium to solve at least one problem existing in the prior art.

[0009] According to a first aspect of the present application, an energy screening method is provided, which includes: obtaining nonlinear energy windows corresponding to different types of rays; selecting the corresponding nonlinear energy windows based on the different types of rays, screening the energy at both ends of a double-ended readout DOI detector obtained based on a target object, and obtaining the energy belonging to the nonlinear energy window at both ends of the double-ended readout DOI detector.

[0010] In some embodiments, obtaining nonlinear energy windows corresponding to different types of rays includes: obtaining peak energies at both ends of a double-ended readout DOI detector based on the different types of rays, wherein the peak energies at both ends satisfy an inverse proportional relationship; and determining a lower limit energy value and an upper limit energy value of the nonlinear energy window based on the peak energies at both ends of the double-ended readout DOI detector.

[0011] In some embodiments, obtaining peak energies at both ends of a dual-end readout DOI detector based on different types of radiation includes: obtaining a dual-end energy spectrum of the dual-end readout DOI detector corresponding to any reaction depth based on a plurality of events corresponding to a scintillation crystal of the dual-end readout DOI detector at the reaction depth; the plurality of events are obtained based on different radiation sources; and obtaining peak energies at both ends of the dual-end readout DOI detector by performing Gaussian fitting on the dual-end energy spectrum.

[0012] In some embodiments, determining the lower limit energy value of the nonlinear energy window includes: multiplying the peak energy at both ends of the double-ended readout DOI detector by the corresponding first coefficient and second coefficient respectively to obtain the first energy and the second energy; and calculating the product of the first energy and the second energy to obtain the lower limit energy value of the nonlinear energy window.

[0013] In some embodiments, determining the upper limit energy value of the nonlinear energy window includes: multiplying the obtained lower limit energy value of the nonlinear energy window by a third coefficient to obtain the upper limit energy value of the nonlinear energy window.

[0014] In some embodiments, the first coefficient, the second coefficient, and the third coefficient are determined according to first a priori information.

[0015] In some embodiments, when the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, obtaining the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector includes obtaining the energy of the single photoelectric conversion element belonging to the nonlinear energy window corresponding to both ends of the single scintillation crystal.

[0016] In some embodiments, when the dual-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to two ends of the single scintillator crystal, and the array of photoelectric conversion elements is coupled to the single scintillator crystal in a many-to-one manner, obtaining the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector includes obtaining the sum of the energies of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of the single scintillator crystal.

[0017] In some embodiments, when the dual-terminal readout DOI detector includes a scintillation crystal array and photoelectric conversion elements coupled to both ends of the scintillation crystal array, the energy of the photoelectric conversion elements corresponding to both ends of a single scintillation crystal and belonging to the nonlinear energy window is acquired separately.

[0018] In some embodiments, when the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of a scintillation crystal array, obtaining the energy belonging to the nonlinear energy window at both ends of a two-terminal readout DOI detector includes obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of the single scintillation crystal, and determining the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

[0019] In some embodiments, the second a priori information includes a correspondence between a position number of a scintillation crystal in a dual-end readout DOI detector and a position number of a photoelectric conversion element that detects an electrical signal.

[0020] In some embodiments, screening the energy at both ends of the double-ended readout DOI detector obtained based on the target object includes: collimating the rays emitted by the target object to obtain rays emitted along the collimation direction toward the scintillation crystal of the double-ended readout DOI detector.

[0021] According to a second aspect of the present application, a reaction depth acquisition method is provided, comprising: acquiring nonlinear energy windows corresponding to different types of radiation; acquiring a correspondence between a priori single-ended energy ratios of a dual-end readout (DOI) detector and a reaction depth of a scintillation crystal based on the nonlinear energy windows corresponding to the different types of radiation, wherein the priori single-ended energy ratio of the dual-end readout (DOI) detector is a ratio of energy at one end to the sum of energy at both ends of the dual-end readout (DOI) detector, obtained based on different radiation sources; acquiring a single-ended energy ratio of the dual-end readout (DOI) detector based on a target object; and acquiring a reaction depth of the scintillation crystal of the dual-end readout (DOI) detector corresponding to the single-ended energy ratio of the dual-end readout (DOI) detector based on the correspondence between the a priori single-ended energy ratio of the dual-end readout (DOI) detector and the reaction depth of the scintillation crystal.

[0022] In some embodiments, obtaining nonlinear energy windows corresponding to different types of rays includes: obtaining peak energies at both ends of a double-ended readout DOI detector based on the different types of rays, wherein the peak energies at both ends satisfy an inverse proportional relationship; and determining a lower limit energy value and an upper limit energy value of the nonlinear energy window based on the peak energies at both ends of the double-ended readout DOI detector.

[0023] In some embodiments, based on a number of events corresponding to a scintillation crystal of a dual-end readout DOI detector at any reaction depth, a dual-end energy spectrum of the dual-end readout DOI detector corresponding to the reaction depth is obtained; the number of events are obtained based on different radiation sources; and the peak energies at both ends of the dual-end readout DOI detector are obtained by performing Gaussian fitting on the dual-end energy spectrum.

[0024] In some embodiments, determining the lower limit energy value of the nonlinear energy window includes: multiplying the peak energy at both ends of the double-ended readout DOI detector by the corresponding first coefficient and second coefficient respectively to obtain the first energy and the second energy; and calculating the product of the first energy and the second energy to obtain the lower limit energy value of the nonlinear energy window.

[0025] In some embodiments, determining the upper limit energy value of the nonlinear energy window includes: multiplying the obtained lower limit energy value of the nonlinear energy window by a third coefficient to obtain the upper limit energy value of the nonlinear energy window.

[0026] In some embodiments, the first coefficient, the second coefficient, and the third coefficient are determined according to first a priori information.

[0027] In some embodiments, obtaining a correspondence between a priori single-ended energy ratio of a dual-end readout DOI detector and a reaction depth of a scintillation crystal based on the nonlinear energy windows corresponding to different types of rays includes: selecting the corresponding nonlinear energy window based on different types of rays, changing the reaction depth position between the rays and the scintillation crystal in the dual-end readout DOI detector, screening the energy at both ends of the dual-end readout DOI detector, and obtaining energy belonging to the nonlinear energy window corresponding to different reaction depth positions; and obtaining a correspondence between a priori single-ended energy ratio of the dual-end readout DOI detector and a reaction depth of the scintillation crystal based on the energy belonging to the nonlinear energy window corresponding to different reaction depth positions.

[0028] In some embodiments, obtaining the correspondence between the a priori single-ended energy ratio of the dual-end readout DOI detector and the reaction depth of the scintillation crystal includes: obtaining the a priori single-ended energy ratio of the dual-end readout DOI detector; and obtaining the correspondence between the a priori single-ended energy ratio and the reaction depth of the scintillation crystal.

[0029] In some embodiments, when the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, obtaining energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining energy belonging to the single photoelectric conversion element of the nonlinear energy window corresponding to different reaction depth positions of the single scintillation crystal.

[0030] In some embodiments, when the dual-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to two ends of the single scintillator crystal, and the array of photoelectric conversion elements is coupled to the single scintillator crystal in a many-to-one manner, obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining the sum of the energies of the photoelectric conversion elements belonging to the nonlinear energy window at two ends of the dual-end readout DOI detector corresponding to different reaction depth positions of the single scintillator crystal.

[0031] In some embodiments, when the dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to two ends of the scintillation crystal array, the energy belonging to the nonlinear energy window corresponding to different reaction depth positions of a single scintillation crystal is acquired separately.

[0032] In some embodiments, when the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of a scintillation crystal array, obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining the sum of the energies of the photoelectric conversion elements belonging to the nonlinear energy window at both ends of a double-ended readout (DOI) detector of the single scintillation crystal at different reaction depth positions, and determining the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

[0033] In some embodiments, the second a priori information includes a correspondence between a position number of a scintillation crystal of a dual-terminal readout DOI detector and a position number of a photoelectric conversion element that detects an electrical signal.

[0034] In some embodiments, obtaining a single-ended energy ratio of a dual-ended readout DOI detector based on a target object includes: collimating rays emitted by the target object to obtain rays emitted along a collimation direction toward a scintillation crystal of the dual-ended readout DOI detector, and obtaining the dual-ended energy of the dual-ended readout DOI detector based on the rays.

[0035] In some embodiments, obtaining a single-end energy ratio of a dual-end readout DOI detector based on a target object includes: obtaining the energy sum of the photoelectric conversion elements corresponding to both ends of the dual-end readout DOI detector based on the target object; and calculating the ratio of the energy sum of the photoelectric conversion elements corresponding to one end to the total energy of the photoelectric conversion elements corresponding to both ends.

[0036] According to a third aspect of the present application, an image reconstruction method is provided, comprising: obtaining a reaction depth of a scintillation crystal in a dual-end readout DOI detector based on the reaction depth acquisition method described in any one of the above embodiments; obtaining image reconstruction information based on the reaction depth information; and performing image reconstruction based on the image reconstruction information.

[0037] In some embodiments, acquiring image reconstruction information based on the reaction depth information includes: acquiring detection data based on the target object; and correcting the detection data based on the reaction depth information to acquire image reconstruction information.

[0038] According to a fourth aspect of the present application, an energy screening device is provided, comprising: a nonlinear energy window acquisition module configured to acquire nonlinear energy windows corresponding to different types of rays; and an energy screening module at both ends configured to select the corresponding nonlinear energy window based on the type of rays of a target object, screen the energy at both ends of a dual-end readout DOI detector acquired based on the target object, and acquire the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector.

[0039] In some embodiments, the energy screening device further comprises: a collimating module configured to collimate the rays emitted by the target object to obtain rays directed toward the scintillation crystal in the double-ended readout DOI detector along the collimation direction.

[0040] In some embodiments, the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal; the two-end energy screening module is further configured to obtain the energy of the single photoelectric conversion element corresponding to the two ends of the single scintillation crystal and belonging to the nonlinear energy window.

[0041] In some embodiments, a two-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to both ends of the single scintillator crystal, wherein the array of photoelectric conversion elements is coupled to the single scintillator crystal in a many-to-one manner; and the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of the single scintillator crystal.

[0042] In some embodiments, a dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to both ends of the scintillation crystal array; the two-end energy screening module is further configured to separately obtain the energy of the photoelectric conversion element corresponding to both ends of a single scintillation crystal and belonging to the nonlinear energy window.

[0043] In some embodiments, the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of the scintillation crystal array; the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of the single scintillation crystal, and determine the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

[0044] In some embodiments, the nonlinear energy window acquisition module includes: a two-end peak energy acquisition module, which is configured to acquire the peak energy at both ends of the dual-end readout DOI detector based on different types of rays, and the peak energy at both ends satisfies an inverse proportional relationship; a nonlinear energy window determination module, which is configured to determine the lower limit energy value and the upper limit energy value of the nonlinear energy window based on the peak energy at both ends of the dual-end readout DOI detector.

[0045] In some embodiments, the two-end energy screening module includes: an energy spectrum acquisition module, which is configured to acquire a two-end energy spectrum of the two-end readout DOI detector corresponding to any reaction depth based on a number of events corresponding to the scintillation crystal in the two-end readout DOI detector at the reaction depth; the several events are acquired based on different radiation sources; and a fitting module, which is configured to acquire the peak energy at both ends of the two-end readout DOI detector by performing Gaussian fitting on the two-end energy spectrum.

[0046] In some embodiments, the nonlinear energy window determination module includes: an energy window lower limit determination module, which is configured to multiply the peak energy at both ends of the double-ended readout DOI detector by the respective corresponding first coefficient and second coefficient to obtain the first energy and the second energy; calculate the product of the first energy and the second energy to obtain the lower limit energy value of the nonlinear energy window; and an energy window upper limit determination module, which is configured to multiply the obtained lower limit energy value of the nonlinear energy window by a third coefficient to obtain the upper limit energy value of the nonlinear energy window.

[0047] According to a fifth aspect of the present application, a reaction depth acquisition device is provided, the reaction depth acquisition device comprising: a nonlinear energy window acquisition module configured to acquire nonlinear energy windows corresponding to different types of rays; a correspondence relationship acquisition module configured to acquire, based on the nonlinear energy windows corresponding to different types of rays, a correspondence relationship between a priori single-ended energy ratio of a double-ended readout DOI detector and a scintillation crystal reaction depth, the priori single-ended energy ratio of the double-ended readout DOI detector being a ratio of one end energy of the double-ended readout DOI detector to the sum of the energies at both ends obtained based on different radiation sources; a ...; a single-ended energy ratio of the double-ended readout DOI detector being a ratio of one end energy of the double-ended readout DOI detector to the sum of the energies at the two ends; a single-ended energy ratio of the double-ended readout DOI detector being a ratio of one end energy of the double-ended readout DOI detector to the sum of the energies at the two ends; a single-ended energy ratio of the double-ended readout DOI detector being a ratio of one end energy of the double-ended readout DOI detector to the sum of the ener A ratio acquisition module is configured to select the corresponding nonlinear energy window based on different types of rays to obtain a single-end energy ratio of the double-end readout DOI detector; the single-end energy ratio of the double-end readout DOI detector is the ratio of the energy at one end of the double-end readout DOI detector to the sum of the energies at both ends obtained based on the target object; and a reaction depth acquisition module is configured to calculate and obtain the reaction depth of the scintillation crystal of the double-end readout DOI detector corresponding to the single-end energy ratio of the double-end readout DOI detector based on the corresponding relationship between the single-end energy ratio of the double-end readout DOI detector and the reaction depth of the scintillation crystal.

[0048] According to a sixth aspect of the present application, an image reconstruction device is provided, comprising: a reaction depth information acquisition module, configured to acquire the reaction depth of a scintillation crystal in a dual-end readout DOI detector based on the reaction depth acquisition device according to claim 39; an image reconstruction information acquisition module, configured to acquire image reconstruction information based on the reaction depth information; and an image reconstruction module, configured to perform image reconstruction based on the image reconstruction information.

[0049] According to a seventh aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in any one of the above embodiments are implemented.

[0050] Based on the above embodiments of the present application, the beneficial effects of the present application include one or more combinations of the following effects:

[0051] In some embodiments, by acquiring the energy within the nonlinear energy window at both ends of a dual-end readout DOI detector, retaining data within the nonlinear energy window, and filtering out other data, scattered events can be effectively removed while retaining more true events, thereby improving DOI resolution. In some embodiments, by acquiring the reaction depth of the dual-end readout DOI detector and correcting the detection data based on the reaction depth, more accurate image reconstruction data can be obtained, improving the accuracy of the reconstructed image. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The following describes the implementation methods of the present application in detail with reference to the accompanying drawings. The accompanying drawings herein constitute a part of the present application and are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the accompanying drawings:

[0053] FIG1 shows an exemplary flow chart of an energy screening method according to an exemplary embodiment of the present application;

[0054] FIG2 shows a schematic diagram of a single scintillation crystal experimental setup according to an exemplary embodiment of the present application;

[0055] FIG3 shows a schematic diagram of a scintillation crystal array experimental device according to an exemplary embodiment of the present application;

[0056] FIG4 is a schematic diagram showing energy distribution after screening using the nonlinear energy window method according to an exemplary embodiment of the present application;

[0057] FIG5 shows an exemplary flow chart of a method for acquiring reaction depth according to an exemplary embodiment of the present application;

[0058] FIG6 shows an exemplary flow chart of an image reconstruction method according to an exemplary embodiment of the present application;

[0059] FIG7 shows an exemplary module diagram of an energy screening device according to an exemplary embodiment of the present application;

[0060] FIG8 shows an exemplary module diagram of a reaction depth acquisition device according to an exemplary embodiment of the present application;

[0061] FIG9 shows an exemplary module diagram of an image reconstruction apparatus according to an example embodiment of the present application. DETAILED DESCRIPTION

[0062] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0063] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 application. In addition, the terms "first" and "second" are used for description only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more similar features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0064] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0065] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in relative height than the second feature in a certain dimension. A first feature being "below," "below," and "below" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is smaller in relative position than the second feature in a certain dimension.

[0066] Provided below are different embodiments or examples for realizing different structures of the present application. In order to simplify the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application. The present application may repeat the reference numerals in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings described. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art can apply other processes and / or substitute uses of other materials according to the teachings of the present application.

[0067] Some preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of the present application.

[0068] FIG1 is an exemplary flow chart of an energy screening method according to some embodiments of the present application. In some embodiments, the energy screening method can be performed by an energy screening device, such as the energy screening device shown in FIG7 . In some embodiments, some programs or instructions stored in a storage device can implement the energy screening method 100 when executed. In some embodiments, the energy screening method 100 can be implemented in software, hardware, firmware, or a combination thereof.

[0069] In the embodiment shown in FIG1 , generally, the energy screening method 100 obtains the energy belonging to the nonlinear energy window at both ends of the double-ended readout DOI detector based on the nonlinear energy window, for subsequent acquisition of reaction depth and image reconstruction.

[0070] Continuing to refer to FIG1 , the energy screening method 100 may include the following steps.

[0071] Step S110: Obtain nonlinear energy windows corresponding to different types of rays.

[0072] In some embodiments, an energy window refers to a closed energy range defined by a lower energy limit and an upper energy limit. A nonlinear energy window refers to an energy window in which corresponding energies satisfy a nonlinear equation. In some embodiments, the corresponding relationship refers to the corresponding energies acquired at both ends of the same crystal in a dual-end readout DOI detector. In some embodiments, the nonlinear equation is an inverse proportional function, meaning that the product of two corresponding energies within the nonlinear energy window is the same.

[0073] In some embodiments, the different types of radiation may be various high-energy radiations, including but not limited to gamma radiation, such as X-rays, alpha radiation, beta radiation, etc. Accordingly, radiation sources generating various radiations include but are not limited to various radiation sources generating gamma radiation (such as sodium radiation sources).

[0074] In some embodiments, nonlinear energy windows corresponding to different types of rays can be used to obtain energy belonging to the nonlinear energy windows at both ends of a double-ended readout DOI detector.

[0075] In some embodiments of the present application, step S110 may further include:

[0076] S111. Acquire peak energies at both ends of a dual-end readout DOI detector based on different types of rays, where the peak energies at both ends satisfy an inverse proportional relationship.

[0077] In some embodiments, a dual-end readout DOI detector includes a scintillation crystal and a photoelectric conversion element coupled to both ends of the scintillation crystal. In some specific examples of the present application, the scintillation crystal can be a LYSO crystal, and the photoelectric conversion element can be a SiPM or PMT, but are not limited thereto. In some specific examples, the scintillation crystal can be a single scintillation crystal or a scintillation crystal array. The photoelectric conversion element can be a single photoelectric conversion element or an array of photoelectric conversion elements. The electrical signal detected by the photoelectric conversion element is connected to a readout device and read out by an ADC or MVT circuit. In some embodiments of the present application, the ADC or MVT circuit can be based on existing mature technologies and will not be described in detail here.

[0078] In some embodiments, S111 may further include:

[0079] S1111. Based on a number of events corresponding to the scintillation crystal of the dual-end readout DOI detector at any reaction depth, obtain a dual-end energy spectrum corresponding to the dual-end readout DOI detector at the reaction depth; the multiple events can be obtained based on different radioactive sources.

[0080] In some embodiments, when obtaining nonlinear energy windows corresponding to different types of radiation, the radiation emitted by the radiation source can be collimated and verified. Specifically, in this embodiment, a double-ended DOI detector and a collimating crystal are located on opposite sides of the radiation source. Only photons oriented in the same direction as the collimating crystal can be detected simultaneously by the double-ended DOI detector and the collimating photoelectric conversion element coupled to the collimating crystal. Radiation emitted by the radiation source simultaneously strikes the collimating crystal and the scintillating crystal of the double-ended DOI detector in opposing directions. The three-terminal photoelectric conversion element then receives signals simultaneously to verify photon deposition. As shown in Figure 2, using a sodium radiation source as an example, the radiation emitted by the sodium radiation source is collimated and verified. Based on whether the signals are received simultaneously by both ends of the double-ended DOI detector and the collimating photoelectric conversion element, it is confirmed whether the energy read out by both ends of the double-ended DOI detector originates from the same energy deposition event. In one specific example, the collimation of radiation emitted by the target object can be verified using a collimating crystal, which can be, but is not limited to, a LYSO crystal. The signal from the collimating crystal is read out by a photoelectric conversion element, which may be, but is not limited to, a SiPM or a PMT. The information detected by the photoelectric conversion element is connected to a readout device and read out by an ADC or MVT circuit.

[0081] In some embodiments, energy information detected by the photoelectric conversion elements at both ends of a dual-end readout DOI detector is recorded as an event. A dual-end energy spectrum corresponding to any reaction depth of a scintillation crystal of the dual-end readout DOI detector is obtained based on a number of events at that reaction depth. This includes obtaining the dual-end energy of the dual-end readout DOI detector corresponding to that reaction depth based on a number of events at that reaction depth of the scintillation crystal of the dual-end readout DOI detector, obtaining the energy corresponding to all events at each end of the dual-end readout DOI detector, and forming a histogram of the energy obtained at each end to obtain the dual-end energy spectrum. See the following for details.

[0082] In some embodiments, a dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal. The single photoelectric conversion element is coupled one-to-one with the single scintillation crystal to obtain energy at both ends of the dual-end readout DOI detector, that is, to obtain the energy measured by the single photoelectric conversion element corresponding to both ends of the single scintillation crystal. After obtaining the energy corresponding to all events measured at each end of the dual-end readout DOI detector based on a number of events, all energies are formed into a histogram to obtain a dual-end energy spectrum.

[0083] In some specific examples of the present application, as shown in Figure 2, a sodium radioactive source 6 is used as a radiation source, and the two ends of the scintillation crystal 1 are respectively coupled to photoelectric conversion devices 2 and 3, such as the first SiPM and the second SiPM (this labeling is not recommended because 1, 2 and other 1, 2 will be confused). The electrical signals detected by the first SiPM and the second SiPM are connected to the readout device and read out by the first channel and the second channel of the ADC, respectively.

[0084] As shown in Figure 2, collimating crystal 4 is used to determine the location of deposited photons. Sodium radiation source 6 and collimating crystal 4 are located at the same height. Collimating crystal 4 is coupled to collimating SiPM 5. The specific depth at which collimating crystal 4 faces scintillation crystal 1 corresponds to the specific depth at which photons are deposited within scintillation crystal 1. When three SiPMs (the first SiPM, the second SiPM, and the collimating SiPM) simultaneously detect a pulse signal, the energy information detected by the first and second SiPMs is recorded as a single event (i.e., a single gamma photon deposition). The energies detected by the first and second SiPMs represent the corresponding two-terminal energies at the two ends of scintillation crystal 1. A priori information indicates that the characteristics of scintillation crystals result in an inversely proportional relationship between the two-terminal energies corresponding to different deposition locations. This means that the energies detected by the first and second SiPMs are inversely proportional. During the test, the positions of the sodium radioactive source and the collimating crystal 4 are moved simultaneously, and several events are collected at the same position. For example, 1000 events can be collected, and the energies at both ends corresponding to each of the 1000 events are obtained. All the energies at one end of each position are plotted into a histogram to obtain a single-ended energy spectrum at that reaction depth. Correspondingly, the single-ended energy spectra corresponding to both ends of each position to which the sodium radioactive source 6 and the collimating crystal 4 are moved are obtained to form a double-ended energy spectrum at that position.

[0085] In some alternative or supplemental embodiments, a dual-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to both ends of the single scintillator crystal. The photoelectric conversion element array is coupled to the single scintillator crystal in a many-to-one manner. Energy at both ends of the dual-end readout DOI detector is acquired, i.e., the sum of the energies of the photoelectric conversion elements corresponding to both ends of the single scintillator crystal is acquired. After acquiring the energies corresponding to all events at each end of the energy at both ends of the dual-end readout DOI detector based on a plurality of events, a histogram of all energies is formed to obtain a dual-end energy spectrum.

[0086] In some other embodiments, a dual-end readout DOI detector includes a scintillation crystal array and photoelectric conversion elements coupled to both ends of the scintillation crystal array, wherein the energy of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of a single scintillation crystal is acquired separately.

[0087] In some specific embodiments, the photoelectric conversion element is a photoelectric conversion element array, and individual photoelectric conversion elements of the photoelectric conversion element array are coupled one-to-one, one-to-many, or many-to-one with individual scintillator crystals of a scintillation crystal array. The energy measured at both ends of a two-terminal readout DOI detector is obtained, i.e., the sum of the energies measured by the corresponding photoelectric conversion elements at both ends of a single scintillator crystal is obtained. Based on a plurality of events, after obtaining the energies corresponding to all events at each end of the two-terminal readout DOI detector, all energies are formed into a histogram to obtain a two-terminal energy spectrum. Specifically, as shown in FIG3 , individual photoelectric conversion elements in photoelectric conversion element arrays 7 and 8, i.e., the third and fourth SiPMs, are coupled many-to-one with individual scintillator crystals in a scintillation crystal array 9. The electrical signals detected by the third and fourth SiPMs are connected to a readout device and read out by the first and second channels of an ADC, respectively. A collimating crystal 10 is used to determine the location of deposited photons. A sodium radiation source 11 is located at the same height as the collimating crystal 10. The collimating crystal 10 is coupled to a photomultiplier tube (PMT) 12. The specific depth of a single scintillator crystal in the collimating crystal 10 that faces the scintillator array 9 corresponds to the specific depth of photon deposition within the scintillator array 9. The signal from the collimating crystal 10 is read by the PMT 12. When the PMT 12, the third SiPM, and the fourth SiPM simultaneously detect a pulse signal, the energy information detected by the third and fourth SiPMs is recorded as a single event (i.e., a single gamma photon deposition).

[0088] In some specific embodiments, the position number of the scintillation crystal can be determined based on the position number of the photoelectric conversion element that detects the electrical signal based on the second priori information. Specifically, the second priori information includes a correspondence between the position number of the scintillation crystal and the position number of the photoelectric conversion element that detects the electrical signal.

[0089] In some embodiments, a dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element array coupled to both ends of the scintillation crystal array. Individual photoelectric conversion elements in the photoelectric conversion element array are coupled one-to-one, one-to-many, or many-to-one to individual scintillation crystals in the scintillation crystal array. Because both ends of the dual-end readout DOI detector are coupled to SiPMs via optical guides, even when a single scintillation crystal is coupled to a single SiPM, the photoelectric conversion elements corresponding to both ends of the same scintillation crystal that can detect electrical signals may be multiple SiPMs. That is, there is a correspondence between the position numbers of the scintillation crystals in the dual-end readout DOI detector and the position numbers of the photoelectric conversion elements that detect electrical signals. This correspondence can be used as second a priori information to facilitate determining the scintillation crystal numbers based on energy information detected at both ends of the dual-end readout DOI detector.

[0090] In some embodiments of the present application, the radiation source and collimating crystal are moved to different reaction positions (i.e., deposition positions) relative to the scintillation crystal of a dual-end readout DOI detector. The dual-end energy spectra obtained by the dual-end readout DOI detector are identical. Therefore, the dual-end energy spectrum can be measured at any reaction depth.

[0091] In the present embodiment, for any reaction depth, several events, including but not limited to several hundred events, are collected to obtain a two-terminal energy spectrum corresponding to the two-terminal readout DOI detector based on the reaction depth. The specific method for obtaining the energy spectrum can be referenced in the prior art and will not be described in detail here.

[0092] In some embodiments of the present application, the double-ended energy spectrum corresponding to the scintillation crystal of the double-ended readout DOI detector at any reaction depth can be obtained based on different types of rays, so as to facilitate the subsequent acquisition of nonlinear energy windows corresponding to different types of rays.

[0093] S1112. Obtain peak energies at both ends of the dual-end readout DOI detector by performing Gaussian fitting on the dual-end energy spectra.

[0094] It is known from prior information that the peak energies at both ends of the dual-end readout DOI detector satisfy an inverse proportional relationship.

[0095] In some embodiments, after obtaining the double-end energy spectra corresponding to several events at a certain reaction depth, the peak energy at both ends of the double-end readout DOI detector can be obtained by performing Gaussian fitting on the double-end energy spectra respectively. The specific operation of Gaussian fitting can refer to the existing technology and will not be repeated here.

[0096] Continuing with the specific examples shown in FIG2 or FIG3, after obtaining the double-ended energy spectrum in step S1111, the energies E1 and E2 corresponding to the double-ended energy spectrum can be obtained by Gaussian fitting. It is known from prior information that the characteristics of the scintillation crystal determine that E1 and E2 satisfy an inverse proportional relationship.

[0097] In some embodiments of the present application, the double-ended energy spectra at both ends of the DOI detector are obtained based on different types of rays. After the peak energies at both ends of the double-ended readout DOI detector are obtained by Gaussian fitting the double-ended energy spectra, the nonlinear energy windows corresponding to the different types of rays can be obtained based on the peak energies at both ends.

[0098] S112 , determining a lower limit energy value and an upper limit energy value of a nonlinear energy window based on the peak energy at both ends of the double-ended readout DOI detector.

[0099] In some embodiments of the present application, based on the peak energy at both ends of the dual-end readout DOI detector, the lower limit energy value and the upper limit energy value of the nonlinear energy window can be determined, thereby obtaining the nonlinear energy windows corresponding to different types of rays.

[0100] In some embodiments, to determine the lower limit energy value of the nonlinear energy window, the peak energy at both ends of the double-ended readout DOI detector can be multiplied by the corresponding first coefficient and second coefficient respectively to obtain the first energy and the second energy; then the product of the first energy and the second energy is calculated to obtain the lower limit energy value of the nonlinear energy window.

[0101] In some embodiments, to determine the upper limit energy value of the nonlinear energy window, the obtained lower limit energy value of the nonlinear energy window may be multiplied by a third coefficient to obtain the upper limit energy value of the nonlinear energy window.

[0102] In the embodiment of the present application, by reasonably setting the upper and lower energy limits of the nonlinear energy window, more real events can be retained without affecting the test accuracy too much.

[0103] In some embodiments, the first coefficient, the second coefficient and the third coefficient are determined according to the first prior information. In some specific examples, the first prior information can be in the form of a coefficient lookup table, which can be determined based on empirical values ​​or obtained based on experiments. The specific operation can refer to the existing technology and will not be described in detail here. Continuing with the example shown in Figure 2, after obtaining the peak energies E1 and E2 corresponding to the double-end energy spectrum in step S1112, the first prior information is searched to obtain the first coefficient, the second coefficient and the third coefficient corresponding to the peak energies at both ends. In some specific examples, the first coefficient and the second coefficient can range from 0.75 to 0.9, and the third coefficient can range from 1.5 to 1.9. For example, the first coefficient is 0.8, the second coefficient is 0.8, and the third coefficient is 1.7. Then the lower limit energy value E of the nonlinear energy window can be determined. 下 For E 下 =0.8E1×0.8E2, the upper limit energy value of the nonlinear energy window E 上 =1.7E 下 , the double-ended energy product is E 下 to E 上 The data between the two values ​​is retained, while all other data is discarded. This is equivalent to creating two curves, y = E / x and y = a × E / x, in a two-terminal distribution scatter plot, and only retaining the data within these two curves. The first and second coefficients, 0.8, are empirically derived; events below 0.8E1 and 0.8E2 are generally considered scattering events. The third coefficient, a = 1.7, is empirically derived; a larger value broadens the energy window and retains more superposition events. In actual testing, the number of high-energy superposition events is far less than the number of true events. Therefore, choosing a larger value for a, such as 1.7, can retain more true events without significantly affecting test accuracy.

[0104] In some embodiments, a dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to both ends of the scintillation crystal array. For a scintillation crystal array, due to differences in the inherent characteristics of each scintillation crystal and the gain of the SiPM coupled to both ends of the scintillation crystal, the dual-end energy spectrum corresponding to each scintillation crystal must be measured individually, and a nonlinear energy window designed for each scintillation crystal is used for energy screening to achieve more accurate energy screening. Specifically, continuing with the example shown in FIG3 , when a scintillation crystal array is used, after step S111, the energy spectrum of each scintillation crystal in the dual-end readout DOI detector is individually obtained, and the energies corresponding to each end of the crystal are obtained based on Gaussian fitting. Then, the nonlinear energy window of each scintillation crystal can be individually designed to achieve better energy screening. Specifically, the design method of the nonlinear energy window of each scintillation crystal is described in the example shown in FIG2 .

[0105] Step S120 , selecting corresponding nonlinear energy windows based on different types of rays, screening the energy at both ends of the double-ended readout DOI detector obtained based on the target object, and obtaining the energy belonging to the nonlinear energy window at both ends of the double-ended readout DOI detector.

[0106] In some embodiments, the target object can generate high-energy rays, including but not limited to gamma rays. The target object can specifically be a radioactive tracer injected into a living organism, or a simulated radiation source, such as a sodium radiation source, but is not limited thereto.

[0107] In some embodiments, screening the energy at both ends of the dual-end readout DOI detector obtained based on the target object includes collimating radiation emitted by the target object to obtain radiation directed toward a scintillation crystal of the dual-end readout DOI detector along the collimated direction. For specific operations, refer to the examples in FIG. 2 and FIG. 3 mentioned in step S1111 and are not further described here.

[0108] In some specific examples of the target object, taking the rays emitted by the target object as gamma photons as an example, the nonlinear energy window corresponding to the gamma photons is selected to screen the energy within the nonlinear energy window at both ends of the double-ended readout DOI detector, and the energy outside the nonlinear energy window is considered to be a scattering event or a superposition event and is discarded, thereby ensuring the accuracy of the screened energy.

[0109] In some embodiments, when a dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, obtaining energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector includes obtaining energy belonging to the nonlinear energy window at the corresponding single photoelectric conversion element at both ends of the single scintillation crystal. Specific energy screening is illustrated in an example in FIG4 . FIG4 is a dual-end energy scatter plot of gamma photons collected by an ADC deposited at 20 different depths on the scintillation crystal of the dual-end readout DOI detector. The horizontal and vertical axes are the dual-end energies E1 and E2, respectively, obtained based on information data from the first and second channels of the ADC. The figure shows that when gamma photons are deposited at different locations, the nonlinear energy window method can effectively filter out low-energy scattered pulses and high-energy superimposed pulses. In other embodiments, energy screening can also be performed using a function that fits the distribution of the dual-end energy scatter plot shown in FIG4 , including but not limited to a piecewise function composed of multiple straight lines.

[0110] In some alternative or supplemental embodiments, when the dual-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to two ends of the single scintillator crystal, and the array of photoelectric conversion elements is coupled to the single scintillator crystal in a many-to-one manner, obtaining energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector includes obtaining the sum of energies belonging to the nonlinear energy window of the photoelectric conversion elements corresponding to the two ends of the single scintillator crystal.

[0111] In some other embodiments, when the dual-end readout DOI detector includes a scintillation crystal array and photoelectric conversion elements coupled to both ends of the scintillation crystal array, the energy of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of a single scintillation crystal is acquired separately.

[0112] In some alternative or supplemental embodiments, when the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of a scintillation crystal array, obtaining the energy belonging to the nonlinear energy window at both ends of the dual-terminal readout DOI detector includes: obtaining the sum of the energies of the photoelectric conversion elements belonging to the nonlinear energy window at both ends of the single scintillation crystal, and determining the position number of the scintillation crystal based on the position number of the photoelectric conversion element that detected the energy information based on second a priori information. In some embodiments, the second a priori information includes a correspondence between the position number of the scintillation crystal of the dual-terminal readout DOI detector and the position number of the photoelectric conversion element that detected the energy information.

[0113] In some embodiments, the energy at both ends of the dual-end readout DOI detector obtained based on the target object is screened. Specifically, this can be done in the following way: the data corresponding to the energy at both ends of the dual-end readout DOI detector within the numerical range of the nonlinear energy window is retained, and other data is screened out. This can effectively remove scattered events while retaining more true events, thereby improving the DOI resolution.

[0114] FIG5 is an exemplary flow chart of a reaction depth acquisition method according to some embodiments of the present application. In some embodiments, the reaction depth acquisition method 200 can be performed by a reaction depth acquisition device, such as the reaction depth acquisition device shown in FIG8 . In some embodiments, some programs or instructions stored in a storage device, when executed, can implement the reaction depth acquisition method 200. In some embodiments, the reaction depth acquisition method 200 can be implemented in software, hardware, firmware, or a combination thereof.

[0115] In the embodiment shown in FIG5 , the reaction depth acquisition method 200 obtains the reaction depth based on a nonlinear energy window, which can be used to correct PET sampling data for accurate image reconstruction.

[0116] Specifically, as shown in FIG5 , the reaction depth acquisition method 200 may include the following steps.

[0117] Step S210: Obtain nonlinear energy windows corresponding to different types of rays.

[0118] In some embodiments, the step S210 may be specifically described with reference to the embodiment shown in step S110 and will not be described in detail here.

[0119] Step S220: Based on the nonlinear energy windows corresponding to different types of radiation, a corresponding relationship between the a priori single-ended energy ratio of the dual-ended readout DOI detector and the reaction depth of the scintillation crystal is obtained. The a priori single-ended energy ratio of the dual-ended readout DOI detector is the ratio of the energy at one end to the sum of the energies at both ends of the dual-ended readout DOI detector obtained based on different radiation sources.

[0120] In some embodiments, after obtaining the nonlinear energy windows corresponding to different types of rays, the corresponding relationship between the a priori single-ended energy ratio of the double-ended readout DOI detector and the scintillation crystal reaction depth can be obtained based on the nonlinear energy windows corresponding to different types of rays.

[0121] In some embodiments, obtaining a correspondence between a priori single-ended energy ratio of a dual-ended readout DOI detector and a scintillation crystal reaction depth based on nonlinear energy windows corresponding to different types of rays includes:

[0122] Step A221: Select corresponding nonlinear energy windows based on different types of rays, change the reaction depth position of the rays and the scintillation crystal in the double-ended readout DOI detector, screen the energy at both ends of the double-ended readout DOI detector, and obtain the energy belonging to the nonlinear energy window corresponding to different reaction depth positions.

[0123] In some embodiments, when the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, obtaining energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector corresponding to different reaction depth positions includes obtaining energy belonging to the nonlinear energy window of the single photoelectric conversion element at both ends of the dual-end readout DOI detector corresponding to different reaction depth positions of the single scintillation crystal.

[0124] In some embodiments, when the dual-end readout DOI detector includes a single scintillator crystal and a photoelectric conversion element array coupled to two ends of the single scintillator crystal, and the photoelectric conversion element array is coupled to the single scintillator crystal in a many-to-one manner, obtaining the energy belonging to the nonlinear energy window at two ends of the dual-end readout DOI detector corresponding to different reaction depth positions includes obtaining the sum of the energies of the photoelectric conversion elements belonging to the nonlinear energy window at two ends of the dual-end readout DOI detector corresponding to different reaction depth positions of the single scintillator crystal.

[0125] In some embodiments, when the dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to both ends of the scintillation crystal array, the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector corresponding to different reaction depth positions of a single scintillation crystal is acquired separately.

[0126] In some embodiments, when the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillator crystal of a scintillator crystal array, obtaining the energy belonging to the nonlinear energy window at both ends of a double-ended readout DOI detector corresponding to different reaction depths includes obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window at both ends of the double-ended readout DOI detector corresponding to different reaction depths of the single scintillator crystal, and determining the position number of the scintillator crystal based on the position number of the photoelectric conversion element that detected the energy information based on second prior information. The second prior information has been described in the previous embodiment and will not be repeated here.

[0127] Step A222: Based on the energies belonging to the nonlinear energy window corresponding to different reaction depth positions, obtain the corresponding relationship between the a priori single-ended energy ratio of the dual-ended readout DOI detector and the reaction depth of the scintillation crystal.

[0128] In some embodiments, obtaining a correspondence between a priori single-ended energy ratio of a dual-ended readout DOI detector and a scintillation crystal reaction depth includes:

[0129] Step A2221: Obtain a priori single-ended energy ratio of the dual-ended readout DOI detector.

[0130] In some embodiments, the a priori single-ended energy ratio of a dual-end readout DOI detector is the ratio of the energy at one end to the sum of the energies at both ends, obtained based on different radiation sources. After obtaining the energies belonging to the nonlinear energy window corresponding to different reaction depths in step A221, the a priori single-ended energy ratio of the dual-end readout DOI detector can be obtained.

[0131] In some specific examples, such as the example shown in FIG2 , based on the gamma rays generated by a sodium radioactive source, after obtaining the energies E1 and E2 corresponding to the double-ended energy spectra of the scintillation crystal in the double-ended readout DOI detector, E1 / (E1+E2) or E2 / (E1+E2) can be used as the prior single-ended energy ratio.

[0132] In some specific examples, such as the example shown in FIG3 , based on the gamma rays generated by a sodium radioactive source, after obtaining the energies E1 and E2 corresponding to the double-ended energy spectra of each scintillation crystal in the double-ended readout DOI detector, E1 / (E1+E2) or E2 / (E1+E2) of each scintillation crystal can be used as the prior single-ended energy ratio.

[0133] Step A2222: Obtain the corresponding relationship between the priori single-ended energy ratio and the scintillation crystal reaction depth.

[0134] In some embodiments, after obtaining the priori single-ended energy ratio, the following linear function model is substituted: y=kx+b (1)

[0135] Among them, y is the reaction depth, x is the prior single-ended energy ratio corresponding to the reaction depth y, k is the coefficient of the linear function, that is, the slope, and b is the constant of the linear function, that is, the intercept.

[0136] In some embodiments, for different types of radiation, the reaction depth position between the radiation and the scintillation crystal in a dual-end readout DOI detector is changed for each type of radiation, and the energy at both ends of the dual-end readout DOI detector is screened to obtain the energy belonging to the nonlinear energy window corresponding to the different reaction depth positions. Based on the obtained energy belonging to the nonlinear energy window, the a priori single-ended energy ratio of the dual-end readout DOI detector is obtained. The a priori single-ended energy ratio is used as the x value, and the reaction depth corresponding to x is used as the y value. k and b are calculated to obtain a linear function model. The linear function model is the corresponding relationship between the a priori single-ended energy ratio of the dual-end readout DOI detector and the reaction depth of the scintillation crystal.

[0137] After the linear function model is obtained, when any single-end energy ratio of the dual-end readout DOI detector is known, the reaction depth corresponding to the single-end energy ratio can be obtained through the linear function model.

[0138] In some specific embodiments, after obtaining the correspondence between the a priori single-ended energy ratio and the reaction depth of the scintillation crystal in the dual-end readout DOI detector for different types of rays, a reaction depth lookup table can be formed. This allows, after obtaining the single-ended energy ratio of the dual-end readout DOI detector based on a certain type of ray, to conveniently and quickly obtain the reaction depth corresponding to the single-ended energy ratio of the ray by looking up the table.

[0139] Step S230 : obtaining a single-end energy ratio of a dual-end readout DOI detector based on the target object.

[0140] In some embodiments, obtaining a single-end energy ratio of a dual-end readout DOI detector based on a target object includes:

[0141] Step S2310: Obtain the sum of the energies of the photoelectric conversion elements corresponding to both ends of the dual-end readout DOI detector based on the target object.

[0142] In some embodiments, the specific operation of step S2310 can refer to the embodiment of step A221 and will not be repeated here.

[0143] Step S2320: Calculate the ratio of the sum of the energies of the photoelectric conversion elements corresponding to one end to the total of the energies of the photoelectric conversion elements corresponding to both ends.

[0144] Specifically, the ratio of the sum of the energies of the photoelectric conversion elements corresponding to one end to the total energies of the photoelectric conversion elements corresponding to both ends is obtained. Reference may be made to the embodiment of step A222 , which will not be described in detail here.

[0145] In some embodiments, obtaining a single-end energy ratio of a dual-end readout DOI detector based on a target object further includes collimating radiation emitted by the target object to obtain radiation directed toward a scintillation crystal in the dual-end readout DOI detector along the collimated direction, and obtaining the dual-end energy of the dual-end readout DOI detector based on the radiation. For details, refer to step S110 in the embodiment and are not further described here.

[0146] Step S240 : Based on the correspondence between the a priori single-ended energy ratio of the dual-ended readout DOI detector and the reaction depth of the scintillation crystal, the reaction depth of the scintillation crystal of the dual-ended readout DOI detector corresponding to the single-ended energy ratio of the dual-ended readout DOI detector is obtained.

[0147] In some specific examples, the single-ended energy ratio p corresponding to a scintillation crystal of the dual-ended readout DOI detector is obtained in step S230, and is substituted into the above formula (1) as the specific value of x to obtain the reaction depth q (i.e., the specific value of y) corresponding to the single-ended energy ratio p.

[0148] In some specific examples, a reaction depth lookup table can be searched, which reflects the correspondence between the prior single-ended energy ratio of the dual-end readout DOI detector and the reaction depth of the scintillation crystal. Therefore, after the single-ended energy ratio p of the dual-end readout DOI detector is known based on the target object (such as the person to be detected), the reaction depth q corresponding to the ratio can be easily and quickly obtained by looking up the table.

[0149] In some embodiments, the meanings or descriptions of the same or similar terms or features of the reaction depth acquisition method 200 can refer to the above-mentioned energy screening method 100, that is, the steps and features of the reaction depth acquisition method 200 can be combined into the energy screening method 100 in a non-contradictory manner.

[0150] In some embodiments, after obtaining the reaction depth corresponding to the single-end energy ratio of the dual-end readout DOI detector, the detection data obtained from the detection object can be corrected based on the reaction depth to obtain more accurate image reconstruction data to improve the accuracy of the reconstructed image.

[0151] FIG6 is an exemplary flow chart of an image reconstruction method according to some embodiments of the present application. In some embodiments, image reconstruction method 300 may be performed by an image reconstruction device, such as the image reconstruction device shown in FIG9 . In some embodiments, programs or instructions stored in a storage device, when executed, may implement image reconstruction method 300. In some embodiments, image reconstruction method 300 may be implemented in software, hardware, firmware, or a combination thereof.

[0152] In the embodiment shown in FIG6 , the image reconstruction method 300 is based on data obtained by a nonlinear energy window and can be used to correct PET sampling data to perform accurate image reconstruction.

[0153] Specifically, as shown in FIG6 , the image reconstruction method 300 may include the following steps.

[0154] Step S310 : Acquire the reaction depth of the scintillation crystal of the dual-end readout DOI detector based on the reaction depth acquisition method of the embodiment shown in FIG. 5 .

[0155] Step S320 : acquiring image reconstruction information based on the reaction depth of the scintillation crystal of the dual-end readout DOI detector.

[0156] Step S330: Perform image reconstruction based on the image reconstruction information to obtain a reconstructed image.

[0157] In some embodiments, step S320 may further include:

[0158] Step S3210: Acquire detection data based on the target object.

[0159] In some embodiments, a multi-voltage threshold (MVT) sampling method is used to digitally sample the detection object to obtain detection data. The multi-voltage threshold method pre-sets several voltage thresholds, inputs the pulse signal and the voltage threshold into the two ends of the comparator at the same time, and measures the time when the comparator outputs the logic pulse flip; these time values ​​and the corresponding voltage thresholds (i.e., time-threshold pairs) constitute the MVT sampling points. The specific MVT sampling method can be referred to the existing technology and will not be described in detail here.

[0160] Step S3220: Correct the detection data based on the response depth of the scintillation crystal of the dual-end readout DOI detector to obtain image reconstruction information.

[0161] Regarding the specific operation of correcting the detection data based on the reaction depth, reference may be made to the prior art and will not be elaborated here.

[0162] In some embodiments, the meanings or descriptions of the same or similar terms or features in the image reconstruction method 300 can refer to the above-mentioned reaction depth acquisition method 200 and energy screening method 100, that is, the steps and features of the reaction depth acquisition method 200 and the energy screening method 100 can be combined into the image reconstruction method 300 in a non-contradictory manner.

[0163] FIG7 is an exemplary module diagram of an energy screening device according to some embodiments of the present application. The energy screening device 400 can implement energy screening based on a nonlinear energy window. As shown in FIG7 , the energy screening device 400 may include:

[0164] A nonlinear energy window acquisition module 410 is configured to acquire nonlinear energy windows corresponding to different types of rays;

[0165] The two-end energy screening module 420 is configured to select corresponding nonlinear energy windows based on different types of rays, screen the energy at both ends of the double-ended readout DOI detector obtained based on the target object, and obtain the energy belonging to the nonlinear energy window at both ends of the double-ended readout DOI detector.

[0166] In some embodiments, the energy screening device 400 may further include a collimation module 430 configured to collimate radiation emitted by the target object to obtain radiation directed toward the scintillation crystal of the dual-end readout DOI detector along the collimation direction. The specific design of the collimation module can be referenced with the embodiment of the energy screening method 100 shown in FIG1 and is not further described here.

[0167] In some embodiments, when the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, the two-end energy screening module is further configured to obtain the energy of the single photoelectric conversion element corresponding to both ends of the single scintillation crystal and belonging to the nonlinear energy window.

[0168] In some embodiments, when the dual-end readout DOI detector includes a single scintillator crystal and an array of photoelectric conversion elements coupled to both ends of the single scintillator crystal, and the array of photoelectric conversion elements is coupled to the single scintillator crystal in a many-to-one manner, the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of the single scintillator crystal.

[0169] In some embodiments, when the dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to both ends of the scintillation crystal array, the two-end energy screening module is further configured to separately obtain the energy of the photoelectric conversion element corresponding to the two ends of a single scintillation crystal and belonging to the nonlinear energy window.

[0170] In some embodiments, when the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of the scintillation crystal array, the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of the single scintillation crystal, and determine the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

[0171] In some embodiments, the nonlinear energy window acquisition module 410 includes:

[0172] A two-end peak energy acquisition module is configured to acquire the peak energy at both ends of the dual-end readout DOI detector based on different types of rays, and the peak energy at both ends satisfies an inverse proportional relationship;

[0173] The nonlinear energy window determination module is configured to determine the lower limit energy value and the upper limit energy value of the nonlinear energy window based on the peak energy at both ends of the double-end readout DOI detector.

[0174] In some embodiments, the nonlinear energy window determination module includes:

[0175] An energy window lower limit determination module is configured to multiply the peak energy at both ends of the double-ended readout DOI detector by the first coefficient and the second coefficient respectively to obtain the first energy and the second energy; and calculate the product of the first energy and the second energy to obtain the lower limit energy value of the nonlinear energy window;

[0176] The energy window upper limit determination module is configured to multiply the obtained lower limit energy value of the nonlinear energy window by a third coefficient to obtain an upper limit energy value of the nonlinear energy window.

[0177] In some embodiments, the two-end energy screening module 420 includes:

[0178] An energy spectrum acquisition module is configured to acquire a double-ended energy spectrum corresponding to a scintillation crystal in a double-ended readout DOI detector at any reaction depth based on a number of events corresponding to the scintillation crystal in the double-ended readout DOI detector at the reaction depth; the number of events is acquired based on different radioactive sources;

[0179] The fitting module is configured to obtain peak energies at both ends of the double-ended readout DOI detector by performing Gaussian fitting on the double-ended energy spectra.

[0180] In the embodiment of the present application, the energy screening device 400 can be used to implement the energy screening method 100 or the methods of other embodiments herein, and can selectively combine features of the energy screening method 100 or other methods, and vice versa.

[0181] In some embodiments, an energy screening device is used to retain energy data at both ends of a dual-end readout DOI detector within the numerical range of a nonlinear energy window and to screen out other data, thereby effectively removing scattered events while retaining more true events, thereby improving DOI resolution.

[0182] FIG8 is an exemplary module diagram of a reaction depth acquisition device according to some embodiments of the present application. The reaction depth acquisition device 500 can acquire the reaction depth based on a nonlinear energy window. As shown in FIG8 , the reaction depth acquisition device 500 includes:

[0183] A nonlinear energy window acquisition module 510 is configured to acquire nonlinear energy windows corresponding to different types of rays;

[0184] A corresponding relationship acquisition module 520 is configured to acquire a corresponding relationship between a priori single-ended energy ratio of a dual-ended readout DOI detector and a scintillation crystal reaction depth based on nonlinear energy windows corresponding to different types of radiation. The priori single-ended energy ratio of the dual-ended readout DOI detector is a ratio of the energy at one end of the dual-ended readout DOI detector to the sum of the energies at both ends, obtained based on different radiation sources.

[0185] The single-end energy ratio acquisition module 530 is configured to select corresponding nonlinear energy windows based on different types of rays to obtain the single-end energy ratio of the dual-end readout DOI detector. The single-end energy ratio of the dual-end readout DOI detector is the ratio of the energy at one end of the dual-end readout DOI detector to the sum of the energies at both ends obtained based on the target object.

[0186] The reaction depth acquisition module 540 is configured to calculate and obtain the reaction depth of the scintillation crystal corresponding to the single-ended energy ratio of the double-ended readout DOI detector based on the corresponding relationship between the single-ended energy ratio of the double-ended readout DOI detector and the reaction depth of the scintillation crystal.

[0187] In some embodiments, the reaction depth acquisition device 500 further includes a collimation module 550 configured to collimate radiation emitted by the target object to obtain radiation directed toward the scintillation crystal of the dual-end readout DOI detector along the collimation direction. The specific design of the collimation module can be referenced with the embodiment of the energy screening method 100 shown in FIG1 and is not further described here.

[0188] In some embodiments, the reaction depth acquisition device 500 also includes an energy screening module at both ends, which is configured to select corresponding nonlinear energy windows based on different types of rays, screen the energy at both ends of the double-ended readout DOI detector obtained based on the target object, and obtain the energy at both ends of the double-ended readout DOI detector belonging to the nonlinear energy window.

[0189] In some embodiments, the correspondence acquisition module 520 is further configured to acquire the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector based on the two-end energy screening module to obtain the prior single-ended energy ratio of the dual-end readout DOI detector; the single-ended energy ratio acquisition module is further configured to acquire the energy belonging to the nonlinear energy window at both ends of the dual-end readout DOI detector based on the two-end energy screening module to obtain the single-ended energy ratio of the dual-end readout DOI detector.

[0190] In some embodiments, the single-ended energy ratio acquisition module 530 is further configured to determine the position number of the scintillation crystal based on second prior information, wherein the second prior information includes a correspondence between the position number of the scintillation crystal of the dual-ended readout DOI detector and the position number of the photoelectric conversion element that detects the electrical signal.

[0191] In an embodiment of the present application, the reaction depth acquisition device 500 can be used to implement the reaction depth acquisition method 200 or the methods described in other embodiments of this document, the method shown in Figure 5, and can selectively combine the features of the reaction depth acquisition method 200 or other methods, and vice versa.

[0192] In some embodiments of the present application, the reaction depth acquisition device 500 may also include components or features of the energy screening device 400 in a non-contradictory manner, or the reaction depth acquisition device 500 may be combined with the energy screening device 400 to obtain a new embodiment, and vice versa.

[0193] In some embodiments, after obtaining the reaction depth of the scintillation crystal of the dual-end readout DOI detector corresponding to the single-end energy ratio of the dual-end readout DOI detector through a reaction depth acquisition device, the detection data obtained from the detection object can be corrected based on the reaction depth to obtain more accurate image reconstruction data and improve the accuracy of the reconstructed image.

[0194] FIG9 is an exemplary block diagram of an image reconstruction apparatus according to some embodiments of the present application. The image reconstruction apparatus 600 can perform image reconstruction based on data reflecting depth correction. As shown in FIG9 , the image reconstruction apparatus 600 includes:

[0195] A reaction depth information acquisition module 610 is configured to acquire the reaction depth of the scintillation crystal in the dual-end readout DOI detector based on the reaction depth acquisition device described in the embodiment shown in FIG8 ;

[0196] An image reconstruction information acquisition module 620 is configured to acquire image reconstruction information based on the reaction depth of the scintillation crystal in the dual-end readout DOI detector;

[0197] The image reconstruction module 630 is configured to perform image reconstruction based on the image reconstruction information.

[0198] In some embodiments, the image reconstruction information acquisition module 620 includes:

[0199] a detection data acquisition module configured to acquire detection data based on a target object;

[0200] The correction module is configured to correct the detection data based on the reaction depth of the scintillation crystal in the dual-end readout DOI detector to obtain image reconstruction information.

[0201] In an embodiment of the present application, the image reconstruction device 600 can be used to implement the image reconstruction method 300 or the methods described in other embodiments of this document, such as the method shown in Figure 6, and can selectively combine the features of the image reconstruction method 300 or other methods, and vice versa.

[0202] In some embodiments of the present application, the image reconstruction device 600 may also include components or features of the energy screening device 400 and the reaction depth acquisition device 500 in a non-contradictory manner, or the image reconstruction device 600 may be combined with the energy screening device 400 and the reaction depth acquisition device 500 to obtain a new embodiment, and vice versa.

[0203] In some embodiments, more accurate image reconstruction data can be obtained through the image reconstruction device to improve the accuracy of the reconstructed image. In some embodiments, the present application also provides a digital device, which may include a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the computer program is executed by the processor, the steps of the energy screening method described in any one of the above embodiments, the steps of the reaction depth acquisition method described in any one of the above embodiments, and the steps of the image reconstruction method described in any one of the above embodiments can be implemented.

[0204] Although not shown, in some embodiments, a computer-readable storage medium is further provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the energy screening method described in any one of the above embodiments, the steps of the reaction depth acquisition method described in any one of the above embodiments, and the steps of the image reconstruction method described in any one of the above embodiments are implemented. The computer program includes various program modules / units that constitute the apparatus according to the embodiments of the present application. When the computer program composed of the various program modules / units is executed, it can implement the functions corresponding to the various steps in the method described in the above embodiments. The computer program can also be run on an electronic device as described in the embodiments of the present application.

[0205] While the basic concepts have been described herein, it will be apparent to those skilled in the art that the detailed disclosure is merely illustrative and does not limit the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to the present application. Such modifications, improvements, and amendments are suggested in the present application and remain within the spirit and scope of the exemplary embodiments of the present application.

[0206] At the same time, this application uses specific terms to describe the embodiments of this application. 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 application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this application does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0207] In addition, it will be understood by those skilled in the art that various aspects of the present application can be illustrated and described by a number of patentable categories or situations, including any new and useful process, machine, product or combination of substances, or any new and useful improvements thereto. Accordingly, various aspects of the present application can be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may all be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". In addition, various aspects of the present application may be represented as a computer product located in one or more computer-readable media, which includes computer-readable program code.

[0208] A computer storage medium may include a propagated data signal embodying the computer program code, for example, in baseband or as part of a carrier wave. The propagated signal may be in a variety of forms, including electromagnetic, optical, or any suitable combination thereof. A computer storage medium may be any computer-readable medium other than a computer-readable storage medium that can be connected to an instruction execution system, apparatus, or device to communicate, propagate, or transfer the program for use. The program code on the computer storage medium may be transmitted via any suitable medium, including radio, cable, fiber optic cable, RF, or similar media, or any combination of these.

[0209] The computer program code required for the operation of each part of the present application can be written in any one or more programming languages, including object-oriented programming languages ​​such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python, etc., conventional procedural programming languages ​​such as C language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages ​​such as Python, Ruby and Groovy, or other programming languages. The program code can be run entirely on the user's computer, or as a separate software package on the user's computer, or partly on the user's computer and partly on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any network form, such as a local area network (LAN) or a wide area network (WAN), or connected to an external computer (e.g., via the Internet), or in a cloud computing environment, or used as a service such as software as a service (SaaS).

[0210] In addition, unless expressly stated in the claims, the order of the processing elements and sequences described in this application, 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 application. Although the above disclosure discusses some of the invention embodiments 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 application. 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.

[0211] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0212] In some embodiments, numbers are used to describe the quantity of components and attributes. 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 stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description 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 the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0213] Each patent, patent application, patent application disclosure, and other materials, such as articles, books, specifications, publications, documents, etc., cited in this application is hereby incorporated by reference in its entirety. This includes application history documents that are inconsistent with or conflict with the content of this application, as well as documents (currently or subsequently attached to this application) that limit the broadest scope of the claims of this application. It should be noted that if the descriptions, definitions, and / or use of terms in the accompanying materials of this application are inconsistent or conflicting with the content of this application, the descriptions, definitions, and / or use of terms in this application shall prevail.

[0214] Finally, it should be noted that the above description is merely an example embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An energy screening method, characterized in that: The energy screening method comprises: Obtain nonlinear energy windows corresponding to different types of rays; The corresponding nonlinear energy window is selected based on different types of rays, the energy at both ends of the double-end readout DOI detector obtained based on the target object is screened, and the energy belonging to the nonlinear energy window at both ends of the double-end readout DOI detector is obtained.

2. The energy screening method according to claim 1, characterized in that: Get the nonlinear energy windows corresponding to different types of rays, including: Acquiring peak energies at both ends of a dual-end readout DOI detector based on different types of rays, wherein the peak energies at both ends satisfy an inverse proportional relationship; Based on the peak energy at both ends of the double-end readout DOI detector, the lower limit energy value and the upper limit energy value of the nonlinear energy window are determined.

3. The energy screening method according to claim 2, characterized in that: Obtain peak energy at both ends of a dual-end readout DOI detector based on different types of rays, including: Based on a number of events corresponding to the scintillation crystal of the double-end readout DOI detector at any reaction depth, obtaining a double-end energy spectrum corresponding to the double-end readout DOI detector at the reaction depth; the several events are obtained based on different radiation sources; The peak energies at both ends of the double-end readout DOI detector are obtained by performing Gaussian fitting on the double-end energy spectrum.

4. The energy screening method according to claim 2, characterized in that: Determine the lower limit energy value of the nonlinear energy window, including: Multiplying the peak energies at both ends of the double-ended readout DOI detector by the first coefficient and the second coefficient corresponding to each other to obtain the first energy and the second energy; The product of the first energy and the second energy is calculated to obtain a lower limit energy value of the nonlinear energy window.

5. The energy screening method according to claim 4, characterized in that: Determine the upper limit energy value of the nonlinear energy window, including: The obtained lower limit energy value of the nonlinear energy window is multiplied by the third coefficient to obtain the upper limit energy value of the nonlinear energy window.

6. The energy screening method according to claim 5, characterized in that: The first coefficient, the second coefficient and the third coefficient are determined according to the first priori information.

7. The energy screening method according to claim 1, characterized in that: When the double-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal, obtaining the energy belonging to the nonlinear energy window at both ends of the double-end readout DOI detector includes obtaining the energy of the single photoelectric conversion element belonging to the nonlinear energy window corresponding to both ends of the single scintillation crystal.

8. The energy screening method according to claim 1, characterized in that: When the double-end readout DOI detector includes a single scintillation crystal and an array of photoelectric conversion elements coupled to two ends of the single scintillation crystal, and the array of photoelectric conversion elements is coupled to the single scintillation crystal in a many-to-one manner, obtaining the energy belonging to the nonlinear energy window at both ends of the double-end readout DOI detector includes obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of the single scintillation crystal.

9. The energy screening method according to claim 1, characterized in that: When the two-terminal readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to two ends of the scintillation crystal array, the energy of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to two ends of a single scintillation crystal is acquired separately.

10. The energy screening method according to claim 9, characterized in that: When the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of a scintillation crystal array, obtaining the energy belonging to the nonlinear energy window at both ends of the double-end readout DOI detector includes obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to both ends of the single scintillation crystal, and determining the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

11. The energy screening method according to claim 10, characterized in that: The second priori information includes a correspondence between a position number of a scintillation crystal in a dual-end readout DOI detector and a position number of a photoelectric conversion element that detects an electrical signal.

12. The energy screening method according to claim 1, characterized in that: The energy at both ends of the double-end readout DOI detector obtained based on the target object is screened, including: collimating the rays emitted by the target object to obtain rays emitted to the scintillation crystal of the double-end readout DOI detector along the collimation direction.

13. A method for obtaining reaction depth, characterized in that: The reaction depth acquisition method comprises: Obtain nonlinear energy windows corresponding to different types of rays; Based on the nonlinear energy windows corresponding to different types of rays, a corresponding relationship between a priori single-ended energy ratio of a double-ended readout DOI detector and a scintillation crystal reaction depth is obtained, wherein the priori single-ended energy ratio of the double-ended readout DOI detector is a ratio of one end energy to the sum of the two end energies of the double-ended readout DOI detector obtained based on different radiation sources; Obtaining the single-end energy ratio of the double-end readout DOI detector based on the target object; Based on the correspondence between the priori single-ended energy ratio of the double-ended readout DOI detector and the reaction depth of the scintillation crystal, the reaction depth of the scintillation crystal of the double-ended readout DOI detector corresponding to the single-ended energy ratio of the double-ended readout DOI detector is obtained.

14. The reaction depth acquisition method according to claim 13, characterized in that: Get the nonlinear energy windows corresponding to different types of rays, including: Acquiring peak energies at both ends of a dual-end readout DOI detector based on different types of rays, wherein the peak energies at both ends satisfy an inverse proportional relationship; Based on the peak energy at both ends of the double-end readout DOI detector, the lower limit energy value and the upper limit energy value of the nonlinear energy window are determined.

15. The reaction depth acquisition method according to claim 14, characterized in that: Obtain peak energy at both ends of a dual-end readout DOI detector based on different types of rays, including: Based on a number of events corresponding to the scintillation crystal of the double-end readout DOI detector at any reaction depth, obtaining a double-end energy spectrum corresponding to the double-end readout DOI detector at the reaction depth; the several events are obtained based on different radiation sources; The peak energies at both ends of the double-end readout DOI detector are obtained by performing Gaussian fitting on the double-end energy spectrum.

16. The reaction depth acquisition method according to claim 14, characterized in that: Determine the lower limit energy value of the nonlinear energy window, including: Multiplying the peak energies at both ends of the double-ended readout DOI detector by the first coefficient and the second coefficient corresponding to each other to obtain the first energy and the second energy; The product of the first energy and the second energy is calculated to obtain a lower limit energy value of the nonlinear energy window.

17. The reaction depth acquisition method according to claim 16, characterized in that: Determine the upper limit energy value of the nonlinear energy window, including: The obtained lower limit energy value of the nonlinear energy window is multiplied by the third coefficient to obtain the upper limit energy value of the nonlinear energy window.

18. The reaction depth acquisition method according to claim 17, characterized in that: The first coefficient, the second coefficient and the third coefficient are determined according to the first priori information.

19. The reaction depth acquisition method according to claim 13, characterized in that: Based on the nonlinear energy windows corresponding to different types of rays, the corresponding relationship between the priori single-end energy ratio of the double-end readout DOI detector and the reaction depth of the scintillation crystal is obtained, including: Selecting the corresponding nonlinear energy window based on different types of rays, changing the reaction depth position of the rays and the scintillation crystal in the double-end readout DOI detector, screening the energy at both ends of the double-end readout DOI detector, and obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions; Based on the energies belonging to the nonlinear energy window corresponding to different reaction depth positions, the corresponding relationship between the a priori single-end energy ratio of the double-end readout DOI detector and the reaction depth of the scintillation crystal is obtained.

20. The reaction depth acquisition method according to claim 19, characterized in that: Obtaining the corresponding relationship between the prior single-end energy ratio of the dual-end readout DOI detector and the scintillation crystal reaction depth, including: Obtaining the a priori single-ended energy ratio of the dual-ended readout DOI detector; The corresponding relationship between the priori single-end energy ratio and the scintillation crystal reaction depth is obtained.

21. The reaction depth acquisition method according to claim 19, characterized in that: When the dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to two ends of the single scintillation crystal, obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining the energy of the single photoelectric conversion element belonging to the nonlinear energy window corresponding to different reaction depth positions of the single scintillation crystal.

22. The reaction depth acquisition method according to claim 19, characterized in that: When the dual-end readout DOI detector includes a single scintillation crystal and an array of photoelectric conversion elements coupled to two ends of the single scintillation crystal, and the array of photoelectric conversion elements is coupled to the single scintillation crystal in a many-to-one manner, obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window at two ends of the dual-end readout DOI detector corresponding to different reaction depth positions of the single scintillation crystal.

23. The reaction depth acquisition method according to claim 19, characterized in that: When the dual-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to two ends of the scintillation crystal array, the energy belonging to the nonlinear energy window corresponding to different reaction depth positions of a single scintillation crystal is acquired separately.

24. The reaction depth acquisition method according to claim 23, characterized in that: When the photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of a scintillation crystal array, obtaining the energy belonging to the nonlinear energy window corresponding to different reaction depth positions includes: obtaining the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window at both ends of a double-end readout DOI detector corresponding to different reaction depth positions of a single scintillation crystal, and determining the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

25. The reaction depth acquisition method according to claim 24, characterized in that: The second priori information includes a correspondence between a position number of a scintillation crystal of a dual-end readout DOI detector and a position number of a photoelectric conversion element that detects an electrical signal.

26. The reaction depth acquisition method according to claim 13, characterized in that: Acquiring a single-end energy ratio of a double-end readout DOI detector based on a target object includes: collimating rays emitted by the target object to obtain rays emitted toward a scintillation crystal of the double-end readout DOI detector along a collimation direction, and acquiring double-end energy of the double-end readout DOI detector based on the rays.

27. The reaction depth acquisition method according to claim 13, characterized in that: Obtain the single-end energy ratio of the dual-end readout DOI detector based on the target object, including: Based on the target object, the energy sum of the photoelectric conversion elements corresponding to the two ends of the double-end readout DOI detector is obtained; The ratio of the energy of the photoelectric conversion element corresponding to one end to the total energy of the photoelectric conversion elements corresponding to both ends is calculated.

28. An image reconstruction method, characterized in that: The image reconstruction method comprises: Acquiring the reaction depth of the scintillation crystal in the dual-end readout DOI detector based on the reaction depth acquisition method described in any one of claims 13 to 27; Acquiring image reconstruction information based on the reaction depth information; Image reconstruction is performed based on the image reconstruction information.

29. The image reconstruction method according to claim 28, characterized in that: Acquiring image reconstruction information based on the reaction depth information includes: Acquire detection data based on the target object; The detection data is corrected based on the reaction depth information to obtain image reconstruction information.

30. An energy screening device, characterized in that: The energy screening device comprises: A nonlinear energy window acquisition module, which is configured to acquire nonlinear energy windows corresponding to different types of rays; The two-end energy screening module is configured to select the corresponding nonlinear energy window based on the type ray of the target object, screen the energy at both ends of the double-end readout DOI detector obtained based on the target object, and obtain the energy belonging to the nonlinear energy window at both ends of the double-end readout DOI detector.

31. The energy screening device according to claim 30, characterized in that: The energy screening device also includes: The collimation module is configured to collimate the rays emitted by the target object to obtain rays emitted along the collimation direction to the scintillation crystal in the double-end readout DOI detector.

32. The energy screening device according to claim 30, characterized in that: The dual-end readout DOI detector includes a single scintillation crystal and a single photoelectric conversion element coupled to both ends of the single scintillation crystal; the two-end energy screening module is further configured to obtain the energy of the single photoelectric conversion element corresponding to both ends of the single scintillation crystal and belonging to the nonlinear energy window.

33. The energy screening device according to claim 30, characterized in that: The double-end readout DOI detector includes a single scintillation crystal and an array of photoelectric conversion elements coupled to the two ends of the single scintillation crystal, and the photoelectric conversion element array is coupled to the single scintillation crystal in a many-to-one manner; the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of the single scintillation crystal.

34. The energy screening device according to claim 30, characterized in that: The double-end readout DOI detector includes a scintillation crystal array and a photoelectric conversion element coupled to the two ends of the scintillation crystal array; the two-end energy screening module is further configured to separately obtain the energy of the photoelectric conversion element corresponding to the two ends of a single scintillation crystal belonging to the nonlinear energy window.

35. The energy screening device according to claim 34, characterized in that The photoelectric conversion element is a photoelectric conversion element array, and a single photoelectric conversion element of the photoelectric conversion element array is coupled one-to-one, one-to-many, or many-to-one with a single scintillation crystal of the scintillation crystal array; the two-end energy screening module is further configured to obtain the energy sum of the photoelectric conversion elements belonging to the nonlinear energy window corresponding to the two ends of a single scintillation crystal, and determine the position number of the scintillation crystal according to the position number of the photoelectric conversion element that detects the electrical signal based on the second prior information.

36. The energy screening device according to claim 30, characterized in that: The nonlinear energy window acquisition module comprises: A two-end peak energy acquisition module, which is configured to acquire peak energies at both ends of the double-end readout DOI detector based on different types of rays, and the two-end peak energies satisfy an inverse proportional relationship; The nonlinear energy window determination module is configured to determine the lower limit energy value and the upper limit energy value of the nonlinear energy window based on the peak energy at both ends of the double-end readout DOI detector.

37. The energy screening device according to claim 36, characterized in that The two-end energy screening module includes: An energy spectrum acquisition module is configured to acquire a double-end energy spectrum corresponding to a scintillation crystal in a double-end readout DOI detector at any reaction depth based on a number of events corresponding to the scintillation crystal in the double-end readout DOI detector at the reaction depth; the number of events are acquired based on different radiation sources; The fitting module is configured to obtain the peak energy at both ends of the double-end readout DOI detector by performing Gaussian fitting on the double-end energy spectrum respectively.

38. The energy screening device according to claim 36, characterized in that Nonlinear energy window determination module, including: The energy window lower limit determination module is configured to multiply the peak energy at both ends of the double-end readout DOI detector by the first coefficient and the second coefficient respectively corresponding to each other to obtain the first energy and the second energy; and obtain the product of the first energy and the second energy to obtain the lower limit energy value of the nonlinear energy window; The energy window upper limit determination module is configured to multiply the obtained lower limit energy value of the nonlinear energy window by a third coefficient to obtain an upper limit energy value of the nonlinear energy window.

39. A reaction depth acquisition device, characterized in that: The reaction depth acquisition device comprises: A nonlinear energy window acquisition module, which is configured to acquire nonlinear energy windows corresponding to different types of rays; A corresponding relationship acquisition module, configured to acquire a corresponding relationship between a priori single-ended energy ratio of a double-ended readout DOI detector and a scintillation crystal reaction depth based on the nonlinear energy windows corresponding to different types of rays, wherein the priori single-ended energy ratio of the double-ended readout DOI detector is a ratio of one end energy to the sum of two end energies of the double-ended readout DOI detector acquired based on different radiation sources; A single-end energy ratio acquisition module is configured to select the corresponding nonlinear energy window based on different types of rays to acquire the single-end energy ratio of the double-end readout DOI detector; the single-end energy ratio of the double-end readout DOI detector is the ratio of the energy at one end of the double-end readout DOI detector acquired based on the target object to the sum of the energies at both ends; The reaction depth acquisition module is configured to calculate and obtain the reaction depth of the scintillation crystal of the double-end readout DOI detector corresponding to the single-end energy ratio of the double-end readout DOI detector based on the corresponding relationship between the single-end energy ratio of the double-end readout DOI detector and the reaction depth of the scintillation crystal.

40. An image reconstruction device, characterized in that: The image reconstruction device comprises: A reaction depth information acquisition module, configured to acquire the reaction depth of the scintillation crystal in the dual-end readout DOI detector based on the reaction depth acquisition device according to claim 39; an image reconstruction information acquisition module, configured to acquire image reconstruction information based on the reaction depth information; The image reconstruction module is configured to perform image reconstruction based on the image reconstruction information.

41. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 29 are implemented.

Images