Spatially encoded crystal array, detector, method, apparatus, and storage medium

Abstract

The application provides a spatially coded crystal array, a detector, a method, a device and a storage medium. The spatially coded crystal array comprises a plurality of scintillation crystal strips and a separation layer. The separation layer is arranged along the depth direction of the scintillation crystal strips and is arranged between adjacent scintillation crystal strips. The spatial distribution of the separation layer satisfies a preset spatial coding function, and the property of the separation layer meets a preset spatial coding property. The application forms a spatially coded separation layer in different regions between the scintillation crystal strips, forms incomplete optical isolation, and thus the spatial distribution information of visible light photons is preserved, and the three-dimensional spatial position information of high-energy photons can be accurately obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-energy photon detection, in particular to a spatially encoded crystal array, a detector, a method, an apparatus, an electronic device and a storage medium. BACKGROUND

[0002] High-energy photons generally refer to photons with energy not lower than 100 eV, including X-rays, gamma rays, alpha particles, beta particles and protons, etc. The resolution capability of a high-energy photon detector for high-energy photon energy information, time information and spatial information directly determines the imaging quality of a detection system. The working principle of a high-energy photon detector is as follows: first, high-energy photons interact with a scintillation crystal to convert the high-energy photons into visible light photons, and the visible light photons are incident into a photoelectric conversion device coupled with the scintillation crystal. The photoelectric conversion device converts the incident visible light into an electric signal, and a digital signal is output and collected by using an electronic system matched with the photoelectric conversion device. Then, the time, energy, position and other information of the high-energy photons can be calculated from the digital signal by using a software algorithm.

[0003] Based on the requirement of a detection system for time performance, the currently applied high-energy photon detector is basically based on a scintillation crystal and a photoelectric conversion device as a basic structure, wherein the scintillation crystal includes LYSO, BGO and YSO, and the photoelectric conversion device includes a position-sensitive PMT, a SiPM and a SPAD.

[0004] At present, the common high-energy photon detector includes the following structures: the first structure is a single-layer scintillation crystal array structure, which is composed of multiple crystal bars combined into a scintillation crystal array, and a light shielding material is used to establish optical isolation between the crystal bars and the outside and between the side surfaces of the crystal bars and the outside. The optical surface at one end of the crystal bar is not covered by the light shielding material, and is coupled with a photoelectric conversion device array through a coupling agent; the second structure is a single-layer scintillation crystal array + light guide layer structure, which adds a light guide layer transparent to visible light photons between the scintillation crystal array and the photoelectric conversion device array. The visible light photons emitted from the scintillation crystal pass through a diverging process and then enter the photoelectric conversion device array; and the third structure is a continuous scintillation crystal structure, which uses an integral continuous scintillation crystal as a scintillator, and a light shielding material is used to establish optical isolation between the scintillator and the outside. The optical surface at one end of the scintillator is not covered by the light shielding material, and is coupled with a photoelectric conversion device array through a coupling agent.

[0005] For the single-layer scintillation crystal array structure, the spatial resolution is limited by the size of the single-layer array scintillation crystal and the photoelectric conversion device, and the two-dimensional spatial distribution of the photons cannot be obtained, and the three-dimensional spatial position information of the high-energy photons cannot be obtained.

[0006] For the continuous scintillation crystal structure, the edge effect is more serious, thus limiting the size of the crystal and causing difficulties in the correction of the detector. SUMMARY

[0007] The present application provides a spatially encoded crystal array, a method, a device, a detector, an electronic device and a storage medium to solve at least one of the above problems.

[0008] According to an aspect of the present application, a spatially encoded crystal array is provided, comprising: a plurality of array-distributed scintillation crystal strips and a spacer layer, the spacer layer being arranged along a depth direction of the scintillation crystal strips and being arranged between adjacent scintillation crystal strips, a spatial distribution of the spacer layer satisfying a preset spatial encoding function, and a property of the spacer layer conforming to a preset spatial encoding property.

[0009] According to some embodiments, the spatial encoding function is a three-dimensional spatial function, a function value of the three-dimensional spatial function being monotonically changed or unchanged in the depth direction.

[0010] According to some embodiments, the spatial encoding function divides the spatially encoded crystal array into a plurality of regions along the depth direction, and the spacer layer is arranged at intervals in each region.

[0011] According to some embodiments, the spacer layer comprises a spacer strip and a transparent strip, and the spatial encoding function satisfies: a height of the spacer strip and the transparent strip in each region is the same along the depth direction, and an interval depth of the spacer strip or the transparent strip in different regions is not completely the same.

[0012] According to some embodiments, the spacer strip is made of a completely opaque material, and the transparent strip is made of a light-transmitting material.

[0013] According to some embodiments, the opaque material comprises an ESR (enhanced spectral reflectance film), a polyester film, a metal reflective film, a titanium monoxide coating and / or a barium sulfate coating.

[0014] According to some embodiments, the transparent material in the plurality of regions comprises air, an optical coupling agent, inorganic glass and / or organic glass.

[0015] According to some embodiments, the spacer layer comprises a plurality of first spacer strips and second spacer strips arranged at intervals.

[0016] According to some embodiments, a depth interval of the first spacer strip and the second spacer strip in each region is the same, and an interval depth of the first spacer strip and the second spacer strip in different regions is not completely the same.

[0017] According to some embodiments, the first spacer strip and the second spacer strip have different refractive indexes.

[0018] According to some embodiments, the spatial encoding function is invariant on the projection plane or satisfies mathematical monotonicity.

[0019] According to some embodiments, the spatial encoding property includes one or more of reflectivity, absorptivity, transmissivity, and refractivity.

[0020] According to some embodiments, the spatial encoding function divides the detector into several regions along the depth direction, and the spatial encoding property of the isolation layer is not completely the same in each region.

[0021] According to some embodiments, the scintillation crystal array is formed by continuous scintillation crystals by laser engraving.

[0022] According to some embodiments, the preset spatial encoding property includes: different regions of adjacent scintillation crystal strips are coated with optical coupling agents or transparent materials with different refractive indexes as isolation layers.

[0023] According to some embodiments, the spatial encoding crystal array includes a plurality of scintillation crystal strips arranged in matrix row and column directions, and different rows or columns of the scintillation crystal strips correspond to one or more scintillation crystal strips of adjacent rows or columns.

[0024] According to an aspect of the present application, a spatial encoding detector is provided, which includes a spatial encoding crystal array as described above and a photoelectric conversion device array coupled with the spatial encoding crystal array.

[0025] According to some embodiments, the photoelectric conversion device array obtains a two-dimensional spatial distribution of incident visible light photons on the projection plane.

[0026] According to some embodiments, the photoelectric conversion device array is coupled at one end or both ends of the spatial encoding crystal array in the depth direction.

[0027] According to some embodiments, a light guide is coupled between the photoelectric conversion device array and the spatial encoding crystal array.

[0028] According to an aspect of the present application, a spatial encoding method is provided, which includes: determining a spatial encoding function of an isolation layer region between different scintillation crystal strips in a detector; determining a spatial encoding property of the isolation layer region according to the spatial encoding function, so that the spatial encoding property of different regions of the isolation layer is different; and changing the shape and property of different regions of the isolation layer according to the spatial encoding function and the spatial encoding property, to complete the spatial encoding of the detector.

[0029] According to some embodiments, the determining the spatial encoding function of the spacer region between different scintillation crystal strips in the detector comprises: determining the interval depth of the spacer region by using a preset three-dimensional spatial function, the three-dimensional spatial function value monotonically changes or does not change on the depth of the scintillation crystal.

[0030] According to some embodiments, the determining the spatial encoding function of the spacer region between different scintillation crystal strips in the detector comprises: using opaque material as the spacer between adjacent scintillation crystal strips in different spacer regions, and using transparent material as the spacer in the region between adjacent scintillation crystal strips without covering opaque material, and the interval of the opaque material and the transparent material respectively satisfies the spatial encoding function.

[0031] According to some embodiments, the opaque material comprises ESR (enhanced spectral reflector), polyester film, metal reflector, titanium monoxide coating and / or barium sulfate coating.

[0032] According to some embodiments, the transparent material comprises air, optical coupling agent, inorganic glass and / or organic glass.

[0033] According to some embodiments, the determining the spatial encoding property of the spacer region comprises: covering transparent material with different refractive indexes as the spacer between adjacent scintillation crystal strips in different spacer regions, so that the refractive indexes of different spacer regions are different.

[0034] According to some embodiments, the determining the spatial encoding property of the spacer region comprises: using transparent material or optical coupling agent as the spacer between adjacent scintillation crystal strips, so that the refractive indexes of different spacer regions satisfy the spatial encoding function.

[0035] According to some embodiments, the spatial encoding function is obtained by using laser internal engraving continuous scintillation crystal, so that the spatial encoding property and / or property of different spacer regions are different.

[0036] According to some embodiments, the using laser internal engraving continuous scintillation crystal comprises: setting different laser parameters for different spacer regions, so that the refractive indexes of the spacer regions are the same as the determined refractive indexes and the refractive indexes of different spacer regions are different.

[0037] According to some embodiments, the laser parameters comprise laser irradiation power, laser irradiation time, laser wavelength and / or laser dot array density.

[0038] According to some embodiments, the shape of the spacer region comprises polygon array or circular array.

[0039] According to an aspect of the present application, a spatial encoding device is provided, which comprises: an encoding function determining unit configured to determine isolated layer regions in a detector that need to be encoded and a spatial encoding function of the isolated layer regions; an encoding property determining unit configured to determine spatial encoding properties of the isolated layer regions, so that the spatial encoding properties of different isolated layer regions are different; and an encoding implementing unit configured to change the shape and / or encoding property of the isolated layer regions according to the spatial encoding function and the spatial encoding properties, so as to complete spatial encoding of the detector.

[0040] According to an aspect of the present application, a spatial decoding method is provided, which is used for a detector as described above, and the method comprises: calculating a statistic corresponding to a deposition position of a high-energy photon, the statistic reflecting a two-dimensional spatial distribution of incident photons corresponding to the deposition position of the high-energy photon; and determining the deposition position of the high-energy photon according to a pre-established spatial encoding corresponding relationship table.

[0041] According to some embodiments, the statistic comprises parameters of a fitted two-dimensional Gaussian function, an average position, an average distance from the average position, a row kurtosis coefficient, a row skewness coefficient, a column kurtosis coefficient and / or a column skewness coefficient.

[0042] According to some embodiments, the corresponding relationship table is obtained by Monte Carlo simulation calculation and / or experimental results under a preset controlled condition of a high-energy photon deposition position.

[0043] According to an aspect of the present application, a spatial decoding method is provided, which is used for a detector as described above, and the method comprises: obtaining a pulse signal output by a photoelectric conversion device array; calculating energy of each channel of the photoelectric conversion device array; calculating a kurtosis coefficient and a skewness coefficient of rows and columns of the photoelectric conversion device array; and looking up a deposition position coordinate based on a pre-established lookup table.

[0044] According to some embodiments, the statistic comprises parameters of a fitted two-dimensional Gaussian function, an average position, an average distance from the average position, a row kurtosis coefficient, a row skewness coefficient, a column kurtosis coefficient and / or a column skewness coefficient.

[0045] According to some embodiments, the corresponding relationship table is obtained by Monte Carlo simulation calculation and / or experimental results under a preset controlled condition of a high-energy photon deposition position.

[0046] According to an aspect of the present application, an electronic device is provided, which comprises: one or more processors; a storage device configured to store one or more programs; and when the one or more programs are executed by the one or more processors, the one or more processors implement a spatial encoding method or a spatial decoding method as described above.

[0047] According to an aspect of the present application, a storage medium is provided, which stores computer program instructions. When the computer program instructions are executed by a processor, the processor implements the spatial encoding method or the spatial decoding method as described above.

[0048] According to some example embodiments of the present application, by forming a spatially encoded isolation layer in different regions between the scintillation crystal strips, thus forming incomplete optical isolation, the spatial distribution information of the visible light photons can be preserved, since the spatial distribution information of the visible light photons is related to the depth and projection position information of the high energy photon deposition, thus the three-dimensional spatial position information of the high energy photons can be obtained from the electrical signal output by the photoelectric conversion device. In addition, the present application has the characteristics of low cost, simple hardware implementation, etc. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the embodiment description will be briefly introduced as follows.

[0050] Figure 1 A top view of a spatially encoded detector according to an example embodiment of the present application is shown.

[0051] Figure 2 A partial schematic diagram of spatial encoding of a single scintillation crystal strip in a detector according to an example embodiment of the present application is shown.

[0052] Figure 3 A partial schematic diagram of another spatial encoding of a single scintillation crystal strip in a detector according to an example embodiment of the present application is shown.

[0053] Figure 4 A side view of visible photon diffusion generated by high energy photon deposition in a detector according to an example embodiment of the present application is shown.

[0054] Figure 5 A flowchart of a spatial encoding method of a detector according to an example embodiment of the present application is shown.

[0055] Figure 6 A spatial encoding device according to an example embodiment of the present application is shown.

[0056] Figure 7 A flowchart of a spatial encoding method according to an example embodiment of the present application is shown.

[0057] Figure 8 A flowchart of another spatial encoding method according to an example embodiment of the present application is shown.

[0058] Figure 9 An electronic device according to an example embodiment of the present application is shown. DETAILED DESCRIPTION

[0059] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0060] The described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of these specific details, or other methods, components, materials, apparatus, or operations may be employed. In these cases, well-known structures, methods, apparatuses, implementations, materials, or operations will not be shown or described in detail.

[0061] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0062] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0063] The specific embodiments according to this application will now be described in detail with reference to the accompanying drawings.

[0064] Figure 1 This diagram shows a top view of a spatially encoded detector according to an example embodiment of this application. The spatially encoded detector includes a scintillation crystal array and an array of photoelectric conversion devices coupled to the scintillation crystal array. Figure 1As shown, the scintillation crystal array includes scintillation crystal strips 10 arranged in rows a and columns b, where a and b are natural numbers greater than or equal to 1, but a and b are not both 1. Between two adjacent scintillation crystal strips 10, an optical material conforming to a spatial coding function and possessing spatial coding properties is disposed according to an example embodiment of this application to form an isolation layer 20. This allows visible light photons generated by high-energy photons deposited in the scintillation crystal array to no longer be confined to a single scintillation crystal strip, but rather diffuse into multiple scintillation crystal strips, thereby preserving the spatial distribution information of the visible light photons.

[0065] Those skilled in the art should note that, Figure 1 In the embodiments, the smaller the actual thickness of the isolation layer 20, the better it is for improving the performance of the detector. The specific thickness of the isolation layer 20 can be determined according to different process requirements. Under known process conditions, the thickness of the isolation layer 20 can be made almost invisible to the naked eye. Figure 1 The embodiments described are for illustrative purposes only and are not intended to limit the scope of the invention.

[0066] exist Figure 1 In the coordinate system shown, the z-axis represents the depth direction of the scintillation crystal, and the x and y axes represent the row or column arrangement directions of the scintillation crystal strips 10. For ease of subsequent description, let the plane with z=0 be the interface between the scintillation crystal array and the photoelectric conversion device array; if a light guide is provided between the scintillation crystal array and the photoelectric conversion device array, then the plane with z=0 is the interface between the scintillation crystal array and the light guide.

[0067] Figure 2 Showing according to Figure 1 A partial schematic diagram of the spatial encoding of a single scintillation crystal strip 10 in the detector of the example embodiment is shown below. Figure 2 The spatial coding structure of a detector according to an example embodiment of this application will be described in detail.

[0068] exist Figure 2 In this embodiment, a single scintillation crystal strip 10 has a top end (not shown in the figure) and a bottom end 12. The plane where the bottom end 12 is located is the plane where z=0. The outer surface of the scintillation crystal strip 10 is divided into several regions A, B, ... of the same or different lengths along the z-axis. The length here is the distance along the Z-axis. In each region, an isolation layer 20 is provided on the outer surface of the scintillation crystal strip 10 according to a preset spatial encoding function.

[0069] For example, in Figure 2In the embodiment, region A is a region where 0 < z < 1 mm. Within region A, 0.1 mm wide isolation bands 21 are set at intervals of 0.1 mm, and the area between adjacent isolation bands 21 is a transparent band 13. Region B is a region where 1 mm < z < 2 mm. Within region B, 0.1 mm wide isolation bands 21 are set at intervals of 0.2 mm, and the area between adjacent isolation bands 21 is a transparent band 13, and so on. The spacing between the opaque isolation bands and the transparent bands satisfies the spatial coding function. Figure 2 The portion not shown is also provided with isolation bands 21 according to the spatial coding function. It should be noted that on any side of the scintillation crystal bar 10, the individual transparent band 13 and isolation band 21 are both rectangular in shape. The top surface of the scintillation crystal bar 10 may or may not be provided with isolation bands 21, while the bottom surface 12 is usually not provided with isolation bands 21 in order to facilitate the conduction of visible light to the photoconductor or photoelectric conversion device array.

[0070] according to Figure 2 After setting up the isolation band 21 in the example, the multiple scintillation crystal strips 10 are then arranged according to... Figure 1 The arrangement shown can form a scintillation crystal array and isolation layer 20. Any process in the art capable of achieving this arrangement and isolation layer distribution can be used, and will not be elaborated further here. The transparent band 13 can be left unfilled or filled with a transparent material that has virtually no impact on the propagation of visible light photons, and will not be elaborated further here.

[0071] According to some embodiments of this application, the isolation strip 21 can block visible light photons inside the scintillation crystal strip 10, thereby preventing visible light photons from penetrating the scintillation crystal strip 10 and entering adjacent scintillation crystal strips 10. For example, the isolation strip 21 can be selected from ESR (Enhanced Spectral Reflectance Coating), polyester film, metal reflective film, titanium monoxide coating, and / or barium sulfate coating. Visible light photons can only be transmitted to other scintillation crystal strips 10 through the transparent strip 13. For example, the transparent strip 13 can be selected from inorganic glass or plexiglass.

[0072] It needs to be further explained that, in Figure 2 In this embodiment, the preset spatial encoding function is preferably a three-dimensional spatial function. The function value of this three-dimensional spatial function changes monotonically or not at all along the depth (z-direction) of the scintillation crystal, so that the correlation between the statistics of the two-dimensional spatial distribution of high-energy photons on the projection plane, i.e., the photosensitive surface of the photoelectric conversion device array, and the depth is as obvious and linear as possible, thereby maximizing the depth resolution of the final reconstruction. Common statistics include the full width at half maximum (FWHM) and kurtosis coefficient of the digital signal acquired by the electronic system. The three-dimensional spatial function describes the functional relationship between the statistics of the two-dimensional spatial distribution of incident high-energy photons on the projection plane and the reaction depth, thus determining the inverse function used to reconstruct the deposition location.

[0073] According to some embodiments, the three-dimensional spatial function values ​​do not change on the projection plane or change in a way that satisfies the monotonicity of mathematics, so that the edge effect is as weak as possible. That is, the relationship between the statistics describing the distribution of high-energy photons in the two-dimensional space of the projection plane and the depth is as inconsequential as possible with the change of the high-energy photon deposition position.

[0074] For example, the duty cycle is defined as the depth of the insulating material covering a unit depth of insulating layer. Assuming the depth of the scintillation crystal is 20 mm, that is... Figure 1 The z-axis direction, as shown, divides the depth into 20 1mm isolation layer regions. The length of the opaque material covering each isolation layer region is determined by a defined three-dimensional space function of duty cycle, for example, L(x, y, z) = (20-z) / 20. From the example three-dimensional space function of duty cycle, it can be seen that when high-energy photons are deposited at a position with a larger z-axis, due to the low duty cycle, visible light photons are easily transported to other parts of the scintillation crystal, resulting in a more diffuse distribution of incident light on the projection plane of the photoelectric conversion device. Statistically, this can be assumed to follow a normal distribution.

[0075] It should be noted that the duty cycle three-dimensional spatial function can also be defined in the x-axis or y-axis direction, which will not be elaborated here.

[0076] Figure 3 Showing according to Figure 1 A partial schematic diagram of another spatial encoding of a single scintillation crystal strip 10 in the detector of the example embodiment is shown below. Figure 3 This application provides a detailed description of the spatial coding structure of a detector according to an example embodiment, wherein... Figure 3 Implementation examples and Figure 2 Compared to the embodiments, the reference numerals for the same or similar parts are indicated by adding an apostrophe.

[0077] exist Figure 3 In this embodiment, a single scintillation crystal strip 10' has a top end (not shown) and a bottom end 12'. The plane containing the bottom end 12' is the plane where z=0. The outer surface of the scintillation crystal strip 10' is divided into several regions A', B', ... of the same or different lengths along the z-direction. In each region, an isolation layer 20 is disposed on the outer surface of the scintillation crystal strip 10' according to a preset function. For example, in... Figure 2In the embodiments, region A' is a region where 0 < z < 1 mm. A first isolation band 21' and a second isolation band 22' are provided within region A'. Both the first isolation band 21' and the second isolation band 22' are 0.1 mm long and are spaced apart. The refractive indices of the first isolation band 21' and the second isolation band 22' for visible light photons are different. Region B' is a region where 1 mm < z < 2 mm. A first isolation band 21' and a second isolation band 22' are also provided within region B'. The first isolation band 21' is 0.1 mm long, and the second isolation band 22' is 0.2 mm long. The first isolation band 21' and the second isolation band 22' are spaced apart. The refractive indices of the first isolation band 21' and the second isolation band 22' for visible light photons are the same as those in region A', and so on. Figure 3 The portion not shown also has a first isolation band 21' and a second isolation band 22' distributed according to this function. It should be noted that on any side of the scintillation crystal bar 10, the individual first isolation band and the second isolation band are rectangular in shape. The top surface of the scintillation crystal bar 10 may or may not have an isolation band, while the bottom surface 12 is usually not provided with an isolation band in order to facilitate the conduction of visible light to the photoconductor or photoelectric conversion device array.

[0078] exist Figure 3 In the embodiments, different parts within the isolation layer region form different spatial coding properties, such as refractive index, which allows visible photons generated by the interaction of high-energy photons with the scintillation crystal to diffuse in the scintillation crystal, thereby preserving the spatial distribution information of visible light photons.

[0079] According to some example embodiments of this application, the refractive index of the isolation layer region is determined using a preset three-dimensional spatial function. Preferably, the value of the three-dimensional spatial function monotonically changes or remains unchanged at the depth of the scintillation crystal, so that the correlation between the statistical quantity of the two-dimensional spatial distribution of high-energy photons on the projection plane, i.e., the photosensitive surface of the photoelectric conversion device array, and the depth is as obvious and linear as possible, thereby maximizing the final reconstructed depth resolution. Common statistical quantities include the full width at half maximum (FWHM) and kurtosis coefficient of the digital signals acquired by the electronic system. The three-dimensional spatial function describes the functional relationship between the statistical quantity of the two-dimensional spatial distribution of incident high-energy photons on the projection plane and the reaction depth, thus determining the inverse function used to reconstruct the deposition location.

[0080] According to some embodiments, the three-dimensional spatial function values ​​do not change on the projection plane or change in a way that satisfies the monotonicity of mathematics, so that the edge effect is as weak as possible, that is, the relationship between the statistics describing the distribution of high-energy photons in the two-dimensional space of the projection plane and the depth is as inconspicuous as possible with the change of the high-energy photon deposition position.

[0081] According to some other embodiments of the present application, for a detector with a continuous scintillation crystal as the scintillation crystal, irradiating the continuous scintillation crystal with a laser beam can form an arrayed or other type of optical structure. The continuous scintillation crystal after being irradiated with a laser beam is also referred to as an internally laser-engraved continuous scintillation crystal.

[0082] According to some exemplary embodiments of the present application, an internally laser-engraved continuous scintillation crystal can be utilized to make the refractive indices of different parts within the isolation layer region different. For example, according to a defined three-dimensional space function, irradiate a determined isolation layer region with a laser to generate an isolation layer region with different refractive indices. The isolation layer region can be a polygon array, for example, a square array or a circular array.

[0083] According to some embodiments, different laser parameters can be set for different isolation layer regions to make the refractive index of the isolation layer region the same as the determined refractive index and the refractive indices of different isolation layer regions different. For example, in the Figure 4 shown z-axis direction, that is, the depth direction of the scintillation crystal, the refractive index of the isolation layer in the region of 0 mm < z < 1 mm is 1.0, the refractive index of the isolation layer in the region of 1 mm < z < 2 mm is 1.1, and the refractive indices in other depth directions (such as the x-axis or y-axis) can be inferred by analogy and will not be elaborated here. Another example is that the refractive index of the isolation layer region of the continuous scintillation crystal satisfies the three-dimensional space function L(x, y, z) = 1 + 0.8×(20 - z) / 20, where the plane of z = 0 is the interface between the scintillation crystal and the photoelectric conversion device.

[0084] According to some embodiments, the laser parameters include laser irradiation power, laser irradiation time, laser wavelength, and / or laser dot density.

[0085] For a detector with a scintillation crystal array as the scintillation crystal, according to some exemplary embodiments of the present application, an optical coupling agent or a transparent material is used as the isolation layer between adjacent crystals in the scintillation crystal array to make the refractive indices of different parts within the isolation layer region different.

[0086] According to some embodiments, opaque materials with different interval lengths and covering the same depth are adopted in different isolation layer regions, for example, ESR (enhanced spectral reflection film), polyester film, metal reflection film, titanium monoxide coating, and / or barium sulfate coating, as the isolation layer between adjacent crystals in the scintillation crystal array, and other contact regions between adjacent crystals use transparent materials, such as inorganic glass and organic glass, as the isolation layer to make the refractive indices of different isolation layer regions different. For example, in the region of 0 mm < z < 1 mm, an isolation layer of 0.1 mm is covered every 0.1 mm, and in the region of 1 mm < z < 2 mm, an isolation layer of 0.1 mm is covered every 0.2 mm, and so on.

[0087] According to electrodynamics, high-energy photons can be both reflected and transmitted at interfaces with different refractive indices.

[0088] Taking LYSO crystal as an example, the refractive index of LYSO crystal is approximately 1.8. Therefore, when z is larger, a greater proportion of visible light photons pass through the isolation layer and enter other scintillation crystal strips, resulting in a more diffuse distribution of incident light on the projection plane of the photoelectric conversion device. Statistically, this distribution can be assumed to conform to a normal distribution.

[0089] It should be noted that the three-dimensional spatial function of refractive index can also be defined in the x-axis or y-axis direction, which will not be elaborated here.

[0090] according to Figure 3 The illustrated embodiment achieves incomplete optical isolation by forming spatially encoded isolation layers in different regions between scintillation crystal strips, thus preserving the spatial distribution information of visible light photons. Since the spatial distribution information of visible light photons is correlated with the depth and projection positions of high-energy photon deposition, the reaction depth can be calculated using this correlation, thereby determining the three-dimensional spatial position information of the high-energy photons. For example, the position of the incident light on the projection plane can be calculated using the centroid method, and the reaction depth can be calculated using the full width at half maximum (FWHM) method.

[0091] Figure 4 A side view showing the diffusion of visible photons generated by high-energy photons in a scintillation crystal according to an exemplary embodiment of this application. Figure 4 In the embodiment, when high-energy photons are deposited in the scintillation crystal strip 10 at the position shown in the figure, at the junction of the scintillation crystal strip 10 and the isolation layer 20, some visible light photons pass through the isolation layer 20 and enter other scintillation crystal strips 10, while others are reflected and continue to propagate in the original scintillation crystal strip 10. Since the deposition position is higher, the visible light photons undergo more transmission and refraction, and the proportion is higher. This results in a more diffuse distribution of the incident light of the photoelectric conversion device 70 on the projection plane 60. Thus, the deposition position of high-energy photons can be determined in reverse based on the light distribution on the projection plane 60.

[0092] Those skilled in the art should note that, in Figures 1-4 In the example embodiment, the shape of the scintillation crystal bar 10 is a cuboid shape, but in this application, the scintillation crystal bar 10 can also be a prism shape, a cylinder shape, or other irregular shape with different numbers of edges.

[0093] Those skilled in the art should also note that, in the above embodiments, the arrangement of the scintillation crystal strips 10 is in the matrix row and column direction, but it can also be an irregular arrangement, including: First, the array of cuboid scintillation crystal strips of the same specification is arranged in an irregular manner, for example, scintillation crystal strips of the same specification are arranged alternately in the x or y direction, and the isolation strip or transparent strip on the side of the same scintillation crystal strip can correspond to two scintillation crystal strips in the adjacent row, so that light passing through the isolation strip or transparent strip can be incident into the corresponding two scintillation crystal strips; Second, cuboid scintillation crystal strips of different specifications are arranged in an irregular manner, for example, the two specifications of scintillation crystal strips are different sizes and are arranged alternately in the x or y direction, and the isolation strip or transparent strip on the side of the larger scintillation crystal strip can correspond to two smaller scintillation crystal strips in the adjacent row, so that light passing through the isolation strip or transparent strip can be incident into the corresponding two scintillation crystal strips; Third, the shapes of the scintillation crystal strips are not completely the same, and their arrangement is not completely regular, for example, some of the scintillation crystal strips are prism-shaped, and some are cylindrical, and the two are arranged alternately. The spatial distribution information of these arrangements and shapes can also be obtained on the projection plane by spatially encoding the isolation layer, which will not be elaborated here.

[0094] Figure 5 A flowchart illustrating a spatial coding method for a detector according to an example embodiment of this application is shown below. Figure 5 This application provides a detailed description of a spatial coding method for a detector according to an example embodiment.

[0095] In step S501, the spatial coding function of the isolation layer region between different scintillation crystal strips in the detector is determined so that subsequent steps can change the transmission path of visible light photons in the detector according to the determined spatial coding function.

[0096] In step S503, the coding properties of the isolation layer region are determined according to the spatial coding function determined in step S501, so that the properties of the isolation layer region are different at different locations. This facilitates the subsequent steps to form isolation layers with different properties in different regions based on the coding properties determined by the isolation layer region. This allows visible photons generated by the interaction between high-energy photons and the scintillation crystal to diffuse in the scintillation crystal, thereby facilitating the detection of the spatial distribution information of visible light photons.

[0097] In step S505, based on the spatial coding function determined in step S501 and the coding properties determined in step S503, the shape and properties of different regions of the isolation layer are changed so that the shape of different regions of the isolation layer conforms to the spatial coding function and the properties of different regions of the isolation layer conform to the determined coding properties, thereby completing the spatial coding of the detector.

[0098] According to some exemplary embodiments of the present application, the spatial encoding function in the above step S501 may be a preset three-dimensional spatial function. Among them, the three-dimensional spatial function value preferably monotonically changes or does not change in the depth of the scintillating crystal bar, so that the correlation between the statistic of the two-dimensional spatial distribution of high-energy photons on the projection plane, that is, the photosensitive surface of the photoelectric conversion device array, and the depth is as obvious as possible and the linearity degree is as good as possible, so that the finally restored depth resolution is as good as possible. Common statistics include the full width at half maximum, kurtosis coefficient, etc. of the digital signals collected by the electronics system. The three-dimensional spatial function describes the functional relationship between the statistic of the two-dimensional spatial distribution of incident photons on the projection plane and the reaction depth, thus determining the inverse function used to restore the deposition projection position.

[0099] According to some embodiments of the present application, the three-dimensional spatial function value does not change on the projection plane or satisfies the change of monotonicity in mathematics, so that the edge effect is as weak as possible, that is: making the relationship between the statistic of the two-dimensional spatial distribution of high-energy photons on the projection plane and the depth as little as possible change with the projection change of the deposition position of high-energy photons.

[0100] For example, in Figure 2 the shown z-axis direction, that is, the depth direction of the scintillating crystal, an isolation layer of 0.1 mm is covered every 0.1 mm in the region of 0 < z < 1 mm, and an isolation layer of 0.1 mm is covered every 0.2 mm in the region of 1 mm < z < 2 mm, and so on.

[0101] According to some embodiments, opaque materials with different depths are covered in different isolation layer regions according to the defined three-dimensional spatial function, and transparent materials are covered in other regions.

[0102] For example, the duty cycle is defined as the length of the isolation material covered in the isolation layer of unit length. Assuming that the depth of the scintillating crystal is 20 mm, that is Figure 2 the shown z-axis direction, the depth is divided into 20 1-mm isolation layer regions. The length of the opaque material covered in each isolation layer region is determined by the defined duty cycle three-dimensional spatial function. For example, L(x, y, z) = (20 - z) / 20.

[0103] From the exemplary duty cycle three-dimensional spatial function, it can be seen that when high-energy photons are deposited at a position with a larger z, because the duty cycle is low, visible light photons are easily transported to other scintillating crystal bars of the detector, making the distribution of the incident light of the photoelectric conversion device on the projection plane more diffuse, and statistically it can be assumed that it satisfies a normal distribution.

[0104] It should be noted here that the three-dimensional spatial function can also be defined in the x-axis or y-axis direction, which will not be elaborated here.

[0105] According to some embodiments of the present application, the encoding property in the above step S503 may be one or several of the reflectivity, absorptivity, refractive index, and transmittance of the isolation layer region.

[0106] According to some embodiments of the present application, the reflectivity can be achieved by covering opaque materials with the same depth at different interval depths in different isolation layer regions. For example, opaque materials such as ESR (Enhanced Spectral Reflective Film), polyester film, metal reflective film, titanium monoxide coating, and / or barium sulfate coating are used as the isolation layer between adjacent scintillation crystal bars in the scintillation crystal array, and other contact regions between adjacent scintillation crystal bars are covered with transparent materials such as air, optical coupling agent, inorganic glass, and organic glass as the isolation layer, so that the reflectivities of different isolation layer regions in step S503 are different. It should be noted that in this embodiment, after covering the opaque material, the reflection means that visible light cannot penetrate the isolation layer region completely, or almost completely cannot penetrate the isolation layer region, for example, more than 90% of the visible light is reflected.

[0107] According to some exemplary embodiments of the present application, the refractive index can be achieved by covering transparent materials with different refractive indices in different isolation layer regions. For example, the transparent materials include air, optical coupling agent, inorganic glass, and / or organic glass, which are used as the isolation layer between adjacent scintillation crystals in the scintillation crystal array, so that the refractive index of the isolation layer region is the same as the determined refractive index and the refractive indices of different isolation layer regions are different. In this embodiment, refraction means that most of the visible light penetrates the isolation layer region and enters the adjacent scintillation crystal bar, for example, more than 90% of the visible light is refracted. During the refraction process, part of the light is often reflected at the same time.

[0108] For example, a transparent material can be covered in the region of 0 < z < 1 mm as the isolation layer between adjacent scintillation crystal bars, so that the refractive index of the isolation layer is 1.0, and a transparent material can be covered in the region of 1 mm < z < 2 mm as the isolation layer between adjacent scintillation crystal bars, so that the refractive index of the isolation layer is 1.1, and so on, to complete the spatial encoding of the refractive index.

[0109] According to some embodiments, the refractive indices of the transparent materials covered in different isolation layer regions are different from the refractive index of the scintillation crystal. According to the theory of electrodynamics, high-energy photons can generate both reflection and transmission at the interface with different refractive indices on both sides.

[0110] According to some embodiments, the refractive index distribution of different isolation layer regions can also satisfy a three-dimensional space function. For example, the refractive index of the isolation layer region satisfies the three-dimensional space function L(x, y, z) = 1 + 0.8×(20 - z) / 20, where the plane of z = 0 is the interface between the scintillation crystal and the photoelectric conversion device.

[0111] According to the theory of electrodynamics, high-energy photons can be reflected and transmitted at the interface with different refractive indices on both sides. The greater the difference in refractive indices on both sides, the higher the proportion of reflection.

[0112] Taking the LYSO crystal as an example, the refractive index of the LYSO crystal is approximately equal to 1.8. Therefore, when z is relatively large, the proportion of visible light photons passing through the isolation layer and entering other crystal bars is greater, which is manifested as a more diffuse distribution of the incident light of the photoelectric conversion device on the projection plane. Statistically, it can be assumed that this distribution conforms to a normal distribution.

[0113] It should be noted here that the three-dimensional space function of the refractive index can also be defined in the x-axis or y-axis direction, which will not be elaborated here.

[0114] For a detector with a continuous scintillation crystal as the scintillation crystal, irradiating the continuous scintillation crystal with a laser beam can form an array or other types of optical structures. The continuous scintillation crystal irradiated with the laser beam is also called an internally laser-engraved continuous scintillation crystal.

[0115] According to some exemplary embodiments of the present application, according to the spatial encoding function determined in step S501 and the encoding property of the isolation layer region determined in step S503, an internally laser-engraved continuous scintillation crystal can be used to make the shapes of the scintillation crystal and the isolation layer the same as those in step S501, and make the encoding property of the isolation layer the same as the encoding property determined in step S503.

[0116] According to some embodiments, according to the defined three-dimensional space function, irradiate the isolation layer region determined in step S501 with a laser to generate an isolation layer region with different refractive indices. The isolation layer region can be a polygon array, for example, a square array or a circular array.

[0117] According to some embodiments, different laser parameters are set for different isolation layer regions to make the refractive index of the isolation layer region the same as the determined refractive index and the refractive indices of different isolation layer regions different.

[0118] For example, in Figure 2 the z-axis direction shown, that is, in the depth direction of the scintillation crystal, the refractive index of the isolation layer in the region of 0 < z < 1 mm is 1.0, and the refractive index of the isolation layer in the region of 1 mm < z < 2 mm is 1.1. The refractive indices in other depth directions, such as the x-axis or y-axis, can be inferred in the same way and will not be elaborated here.

[0119] For another example, the refractive index of the isolation layer region of the continuous scintillation crystal satisfies the three-dimensional space function L(x, y, z) = 1 + 0.8×(20 - z) / 20, where the plane of z = 0 is the interface between the scintillation crystal and the photoelectric conversion device.

[0120] According to some embodiments, laser parameters include laser irradiation power, laser irradiation time, laser wavelength, and / or laser dot density.

[0121] According to some example embodiments of this application, an optical coupling agent or a transparent material can also be used as an isolation layer between adjacent scintillation crystal strips in a scintillation crystal array, so that the refractive index of the isolation layer region determined in step S503 meets the spatial coding requirements.

[0122] according to Figure 5 The illustrated embodiment achieves incomplete optical isolation by forming different refractive indices in different isolation layer regions within the detector, thereby preserving the spatial distribution information of visible light photons. This spatial distribution information is correlated with the depth and projection positions of the high-energy photon deposition. Therefore, the reaction depth can be calculated using the correlation between the spatial distribution information of visible light photons and the depth and projection positions of the high-energy photon deposition, thus determining the three-dimensional spatial position information of the high-energy photons. For example, the position of the incident light on the projection plane can be calculated using the centroid method, and the reaction depth can be calculated using the full width at half maximum (FWHM) method.

[0123] Figure 6 This application illustrates a spatial coding apparatus according to an example embodiment of the present application. The spatial coding apparatus includes a coding function determination unit 601, a coding property determination unit 603, and a coding implementation unit 605. The coding function determination unit 601 is used to determine the isolation layer region in the detector that needs to be coded and the spatial coding function of the isolation layer region. The coding property determination unit 603 is used to determine the coding property of the isolation layer region, such that different isolation layer regions have different coding properties. The coding implementation unit 605 is used to change the shape and / or coding property of the isolation layer region according to the spatial coding function and the coding property, so that the shape of different regions of the isolation layer conforms to the spatial coding function and the property of different regions of the isolation layer conforms to the determined coding property, thereby completing the spatial coding of the detector.

[0124] Figure 7 A flowchart illustrating a spatial encoding method according to an example embodiment of this application is shown.

[0125] In step S701, the statistics corresponding to the deposition location of the high-energy photons are calculated.

[0126] According to some example embodiments of this application, when high-energy photons are deposited at different depths in a scintillation crystal strip, the incident light of the photoelectric conversion device is distributed differently on the projection plane after passing through the spatially encoded isolation layer. Statistically, it can be assumed that it follows a normal distribution.

[0127] Therefore, a two-dimensional Gaussian function can be used to fit the energy of each scintillation crystal in the scintillation crystal array. For example, a two-dimensional Gaussian function can be used to fit the energy of each scintillation crystal in the normalized scintillation crystal array. The statistic corresponding to the deposition position of high-energy photons calculated in step S701 is a two-dimensional Gaussian function corresponding to the normalized energy value of each scintillation crystal.

[0128] In step S703, the deposition location of high-energy photons is determined according to the pre-established spatial coding correspondence table.

[0129] According to some embodiments, before executing step S703, a spatial encoding correspondence table needs to be pre-established. This table includes the relationship between deposition location and statistical parameters. For example, Monte Carlo simulation is used to establish the relationship between the coordinates (x, y, z) of high-energy photon deposition and the parameters of a two-dimensional Gaussian function. Then, based on the two-dimensional Gaussian function calculated in step S701 and the pre-established relationship table between deposition location and the parameters of the two-dimensional Gaussian function, the coordinates (x, y, z) of the high-energy photon deposition are determined. Alternatively, the coordinates can be obtained through experimental results under controlled high-energy photon deposition locations, which will not be elaborated here.

[0130] according to Figure 7 The illustrated embodiment utilizes the correlation between the spatial distribution information of visible light photons and the depth information of high-energy photon deposition to obtain the reaction depth information of high-energy photons from the electrical signal output by the photoelectric conversion device. Compared with existing solutions, this embodiment has the advantages of low cost and low hardware complexity.

[0131] Figure 8 A flowchart illustrating another spatial encoding method according to an example embodiment of this application is shown. The following is specifically for… Figure 8 This application provides a detailed description of another spatial encoding method according to an example embodiment.

[0132] In step S801, the pulse signal output by the photoelectric conversion device array is acquired.

[0133] According to some embodiments, the pulse signals output by each channel of the photoelectric conversion device array can be digitized using multi-voltage threshold sampling or regular time sampling.

[0134] In step S803, the energy of each channel of the photoelectric conversion device array is calculated.

[0135] According to some embodiments, the integral value of the electrical signal pulse can be reconstructed from the sampling point data of the pulse signal by summing, fitting and integrating or establishing a lookup table. The integral value contains the energy of each channel. The energy of each channel of the photoelectric conversion device can be reconstructed by linear correction, nonlinear correction or establishing a lookup table.

[0136] In step S805, the kurtosis coefficient and skewness coefficient of the rows and columns of the photoelectric conversion device array are calculated.

[0137] According to some implementations, before obtaining the kurtosis and skewness coefficients, it is necessary to first obtain the spatial coordinates (x1, y1) of the channel with the highest energy based on the energy of each channel. For example, by inputting the energy of each channel and the spatial position of each channel, the spatial position (x1, y1) of the channel with the highest energy can be obtained.

[0138] According to some embodiments, based on the energy of each channel and its position in space, the energies of all channels in the same row are summed to obtain the total channel energy sequence for each row. Similarly, the total channel energy sequence for each column can be obtained. By inputting the row number and the total energy, the row kurtosis coefficient and row skewness coefficient can be calculated. Similarly, the column kurtosis coefficient and column skewness coefficient can be calculated.

[0139] In S807, the coordinates of the deposition location are found based on a pre-established lookup table.

[0140] According to some embodiments, by performing Monte Carlo simulation and / or experiments, a lookup table is established between high-energy photon deposition positions (x, y, z) and (x1, y1), average position, average distance between average positions, row kurtosis coefficient, row skewness coefficient, column kurtosis coefficient, and column skewness coefficient by executing steps S801 to S805.

[0141] In step S807, based on the established lookup table, the high-energy photon deposition location coordinates (x, y, z) are reconstructed according to (x1, y1), row kurtosis coefficient, row skewness coefficient, column kurtosis coefficient, column skewness coefficient, and the lookup table.

[0142] according to Figure 8 The illustrated embodiment, based on the spatial distribution information of visible light photons, the depth information of high-energy photon deposition, and the correlation between projection positions, achieves the acquisition of high-energy photon reaction depth information from the pulse signal output by the photoelectric conversion device. Compared with existing solutions, this embodiment has the advantages of low cost and low hardware complexity.

[0143] Figure 9 A block diagram of an electronic device according to an embodiment of this application is shown. Figure 9 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0144] like Figure 9As shown, this electronic device is presented in the form of a general-purpose computing device. The components of this electronic device may include, but are not limited to: at least one processor 910, at least one memory 920, a bus 930 connecting different system components (including the memory 920 and the processor 910), a display unit 940, etc. The memory 920 stores program code, which can be executed by the processor 910, causing the processor 910 to perform the methods described in this specification according to the various exemplary embodiments of this application. For example, the processor 910 can perform, as... Figure 5 , Figure 7 or Figure 8 The method shown.

[0145] The memory 920 may include a readable medium in the form of volatile memory cells, such as random access memory (RAM) 9201 and / or cache memory 9202, and may further include read-only memory (ROM) 9203.

[0146] The memory 920 may also include a program / utility 9204 having a set (at least one) of program modules 9205, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0147] Bus 930 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0148] The electronic device can also communicate with one or more external devices 900 (e.g., keyboard, pointing device, Bluetooth device, etc.), one or more devices that enable a user to interact with the electronic device, and / or any device that enables the electronic device to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 950. Furthermore, the electronic device can communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 960. Network adapter 960 can communicate with other modules of the electronic device via bus 930. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with the electronic device, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0149] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. The technical solutions according to the embodiments of this application can be embodied in the form of a software product, which can be stored in a computer-readable storage medium (such as a CD-ROM, USB flash drive, or external hard drive) or on a network, including several computer program instructions to cause a computing device (such as a personal computer, server, or network device, etc.) to execute the methods described above according to the embodiments of this application.

[0150] Software products may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0151] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0152] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0153] The aforementioned computer-readable medium carries one or more program instructions that, when executed by a device, cause the computer-readable medium to perform the aforementioned functions.

[0154] Those skilled in the art will understand that the above modules can be distributed in the device as described in the embodiments, or they can be modified accordingly to be uniquely different from one or more devices in this embodiment. The multiple modules of the above embodiments can be combined into one module, or a single module can be further divided into multiple sub-modules.

[0155] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. The technical solutions according to the embodiments of this application can be embodied in the form of a software product, which can be stored in a computer-readable storage medium (such as a CD-ROM, USB flash drive, or external hard drive) or on a network, including several computer program instructions to cause a computing device (such as a personal computer, server, or network device, etc.) to execute the methods described above according to the embodiments of this application.

[0156] Software products may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0157] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0158] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0159] The aforementioned computer-readable medium carries one or more program instructions that, when executed by a device, cause the computer-readable medium to perform the aforementioned functions.

[0160] Those skilled in the art will understand that the above modules can be distributed in the device as described in the embodiments, or they can be modified accordingly to be uniquely different from one or more devices in this embodiment. The multiple modules of the above embodiments can be combined into one module, or a single module can be further divided into multiple sub-modules.

[0161] According to some example embodiments of this application, by spatially encoding the isolation layer in different regions of the detector to form incomplete optical isolation, the spatial distribution information of visible light photons can be preserved. Since the spatial distribution information of visible light photons is related to the depth information and projection position of high-energy photon deposition, the reaction depth of high-energy photons can be obtained from the signal output by the photoelectric conversion device, thereby determining its three-dimensional spatial position information. Moreover, this application has the characteristics of low cost and simple hardware implementation.

[0162] While this application provides the operational steps of the methods described in the above embodiments or flowcharts, the methods may include more or fewer operational steps based on conventional or non-inventive methods. For steps where there is no logically necessary causal relationship, the execution order of these steps is not limited to the execution order provided in the embodiments of this application.

[0163] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0164] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. Furthermore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A spatially encoded crystal array, characterized in that, The spatial coding crystal array includes: The array comprises multiple scintillation crystal strips and isolation layers. The isolation layers are disposed along the depth direction of the scintillation crystal strips and are located between adjacent scintillation crystal strips. The spatial distribution of the isolation layers satisfies a preset spatial coding function, and the properties of the isolation layers conform to preset spatial coding properties, so as to determine the deposition position of high-energy photons in the scintillation crystal strips according to the spatial coding function. The spatial coding function divides the spatially coded crystal array into several regions along the depth direction, and the isolation layers are arranged at intervals in each region.

2. The spatially encoded crystal array according to claim 1, characterized in that, The spatial encoding function is a three-dimensional spatial function, and the function value of the three-dimensional spatial function changes monotonically or does not change in the depth direction.

3. The spatially encoded crystal array according to claim 1, characterized in that, The isolation layer includes an isolation band and a transparent band, and the spatial encoding function satisfies the following: the isolation band and the transparent band in each region have the same height along the depth direction, and the spacing depth of the isolation band or transparent band in different regions is not exactly the same.

4. The spatially encoded crystal array according to claim 3, characterized in that, The isolation strip is made of a completely opaque material, while the transparent strip is made of a light-transmitting material.

5. The spatially encoded crystal array according to claim 4, characterized in that, The opaque material includes ESR, polyester film, metal reflective film, titanium monoxide coating and / or barium sulfate coating.

6. The spatially encoded crystal array according to claim 4, characterized in that, The light-transmitting material includes air, optical coupling agent, inorganic glass and / or plexiglass.

7. The spatially encoded crystal array according to claim 1, characterized in that, The isolation layer includes a plurality of first isolation strips and second isolation strips spaced apart.

8. The spatially encoded crystal array according to claim 7, characterized in that, The first isolation strip and the second isolation strip within each region have the same depth interval, but the depth interval between the first isolation strip and the second isolation strip in different regions is not exactly the same.

9. The spatially encoded crystal array according to claim 7, characterized in that, The first isolation zone and the second isolation zone have different refractive indices.

10. The spatially encoded crystal array according to claim 1, characterized in that, The spatial encoding function either does not change on the projection plane or changes in a manner that satisfies mathematical monotonicity.

11. The spatially encoded crystal array according to claim 1, characterized in that, The spatial coding properties include one or more of reflectivity, absorptivity, transmissivity, and refractive index.

12. The spatially encoded crystal array according to claim 11, characterized in that, The spatial coding function divides the detector into several regions along the depth direction, and the spatial coding properties of the isolation layer are not exactly the same in each region.

13. The spatially encoded crystal array according to claim 1, characterized in that, The scintillation crystal array is formed by laser engraving of continuous scintillation crystals.

14. The spatially encoded crystal array according to claim 1, characterized in that, The preset spatial coding properties include: coating adjacent scintillation crystal strips in different regions with optical coupling agents or transparent materials of different refractive indices as isolation layers.

15. The spatially encoded crystal array according to claim 1, characterized in that, The spatially encoded crystal array includes multiple scintillation crystal strips arranged in a matrix row and column direction, with each scintillation crystal strip in a different row or column corresponding to one or more scintillation crystal strips in an adjacent row or column.

16. A spatial coding detector, characterized in that, The spatial coding detector includes a spatial coding crystal array as described in any one of claims 1-15 and an array of photoelectric conversion devices coupled to the spatial coding crystal array.

17. The spatial coding detector according to claim 16, characterized in that, The photoelectric conversion device array acquires the two-dimensional spatial distribution of incident visible light photons on the projection plane.

18. The spatial coding detector according to claim 16, characterized in that, The photoelectric conversion device array is coupled at one or both ends of the spatial coding crystal array along its depth direction.

19. The spatial coding detector according to claim 16, characterized in that, A light guide is coupled between the photoelectric conversion device array and the spatial coding crystal array.

20. A spatial coding method, characterized in that, The spatial coding method includes: A spatial coding function is determined for the isolation layer region between different scintillation crystal strips in the detector. The spatial coding function divides the spatial coding crystal array into several regions along the depth direction, and the isolation layers are arranged at intervals in each region. The spatial coding properties of the isolation layer region are determined according to the spatial coding function, so that the spatial coding properties of different regions of the isolation layer are different. Based on the spatial coding function and the spatial coding properties, the shape and properties of different regions of the isolation layer are changed to complete the spatial coding of the detector, so as to determine the deposition position of high-energy photons in the scintillation crystal strip according to the spatial coding function.

21. The spatial coding method according to claim 20, characterized in that, The spatial coding function for determining the isolation layer region between different scintillation crystal strips in the detector includes: The spacing depth of the isolation layer region is determined using a preset three-dimensional spatial function, the value of which varies monotonically or does not change at the depth of the scintillation crystal.

22. The spatial coding method according to claim 20, characterized in that, The spatial coding function for determining the isolation layer region between different scintillation crystal strips in the detector includes: In different isolation layer regions, an opaque material is used as an isolation layer between adjacent scintillation crystal strips, and a transparent material is used as an isolation layer in the regions between adjacent scintillation crystal strips that are not covered by the opaque material. The spacing between the opaque material and the transparent material satisfies the spatial coding function.

23. The spatial coding method according to claim 22, characterized in that, The opaque materials include ESR, polyester film, metal reflective film, titanium monoxide coating and / or barium sulfate coating.

24. The spatial coding method according to claim 22, characterized in that, The transparent material includes air, optical coupling agent, inorganic glass and / or plexiglass.

25. The spatial coding method according to claim 20, characterized in that, Determining the spatial coding properties of the isolation layer region includes: Different isolation layer regions are covered with transparent materials of different refractive indices as isolation layers between adjacent scintillation crystal strips, so that the refractive indices of the different isolation layer regions are different.

26. The spatial coding method according to claim 20, characterized in that, Determining the spatial coding properties of the isolation layer region includes: An optical coupling agent or a transparent material is used as an isolation layer between adjacent scintillation crystal strips so that the refractive index of different isolation layer regions satisfies the spatial coding function.

27. The spatial coding method according to claim 20, characterized in that, The spatial coding function utilizes a laser-engraved continuous scintillation crystal to make the spatial coding properties and / or properties different in different isolation layer regions.

28. The spatial coding method according to claim 27, characterized in that, The method of using laser internal engraving for continuous scintillation crystal includes: Different laser parameters are set for different isolation layer regions, so that the refractive index of the isolation layer region is the same as the determined refractive index, and the refractive index of different isolation layer regions is different.

29. The spatial coding method according to claim 28, characterized in that, The laser parameters include laser irradiation power, laser irradiation time, laser wavelength, and / or laser dot density.

30. The spatial coding method according to claim 20, characterized in that, The shapes of different regions of the isolation layer include polygonal arrays or circular arrays.

31. A spatial coding device, characterized in that, The spatial coding device includes: The coding function determination unit is used to determine the isolation layer region in the detector that needs to be coded and the spatial coding function of the isolation layer region. The spatial coding function divides the spatial coding crystal array into several regions along the depth direction, and the isolation layers are arranged at intervals in each region. The encoding property determination unit is used to determine the spatial encoding properties of the isolation layer regions, so that different isolation layer regions have different spatial encoding properties. The encoding implementation unit is used to change the shape and / or encoding properties of the isolation layer region according to the spatial encoding function and the spatial encoding properties to complete the spatial encoding of the detector, so as to determine the deposition position of high-energy photons in the scintillation crystal strip according to the spatial encoding function.

32. A spatial decoding method for a detector as described in any one of claims 16-19, characterized in that, The method includes: Calculate the statistics corresponding to the deposition locations of high-energy photons; The deposition location of the high-energy photons is determined according to a pre-established spatial coding correspondence table.

33. The spatial decoding method according to claim 32, characterized in that, The statistics include the parameters of the fitted two-dimensional Gaussian function, the mean position, the mean distance between the mean position and the mean position, the row kurtosis coefficient, the row skewness coefficient, the column kurtosis coefficient and / or the column skewness coefficient.

34. The spatial decoding method according to claim 32, characterized in that, The correspondence table is obtained using Monte Carlo simulation calculations and / or pre-set experiments.

35. A spatial decoding method for a detector as described in any one of claims 16-19, characterized in that, The method includes: Acquire the pulse signal output by the photoelectric conversion device array; Calculate the energy of each channel of the photoelectric conversion device array; Calculate the kurtosis and skewness coefficients of the rows and columns of the photoelectric conversion device array; The coordinates of the deposition location are found based on a pre-established lookup table.

36. An electronic device, characterized in that, The electronic device includes: One or more processors; Storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the spatial encoding method as described in any one of claims 20-30 or the spatial decoding method as described in any one of claims 32-35.

37. A storage medium storing computer program instructions thereon, characterized in that, When the computer program instructions are executed by the processor, the processor implements the spatial encoding method as described in any one of claims 21-31 or the spatial decoding method as described in any one of claims 32-35.

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