WO2024131738A1 - Crystal array detector and emission imaging device - Google Patents

Crystal array detector and emission imaging device Download PDF

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Publication number
WO2024131738A1
WO2024131738A1 PCT/CN2023/139612 CN2023139612W WO2024131738A1 WO 2024131738 A1 WO2024131738 A1 WO 2024131738A1 CN 2023139612 W CN2023139612 W CN 2023139612W WO 2024131738 A1 WO2024131738 A1 WO 2024131738A1
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Prior art keywords
scintillation
crystal
scintillation crystals
crystals
crystal array
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PCT/CN2023/139612
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French (fr)
Chinese (zh)
Inventor
顾峥
赵鑫
何文
赵阳洋
黄文杰
张志在
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深圳湾实验室
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Publication of WO2024131738A1 publication Critical patent/WO2024131738A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material

Definitions

  • the present invention relates to an emission imaging system, in particular to a crystal array detector and an emission imaging device having the crystal array detector.
  • Emission Computed Tomography is an imaging technology that can display the distribution of radionuclides at all levels in the body and three-dimensional distribution images. This technology uses the tracer principle of radionuclides to detect the rays emitted by the decay of radionuclides and forms images through data processing.
  • ECT is currently divided into two categories. One is used to detect the distribution of radionuclides that can emit gamma rays in the body, called Single Photon Emission Computed Tomography (SPECT); the other is used to detect the annihilation radiation of radionuclides that can emit positrons, called Positron Emission Computed Tomography (PET).
  • PET imaging has been widely used in related fields of medical imaging.
  • PET imaging detects two gamma photons emitted in opposite directions when positrons are annihilated, and reconstructs the three-dimensional distribution of positron tracers in the body through computers.
  • ICS inter-crystal scattering events
  • PET imaging technology dedicated to small animal imaging is an important tool for the transformation of molecular biology to the clinic. Because small animals are much smaller in size and mass than humans, in order to obtain image details equivalent to those that can be obtained by human PET imaging, PET imaging for small animals requires higher system sensitivity and spatial resolution.
  • ICS inter-crystal scattering events
  • the prior art In order to screen out ICS events from the total events, the prior art often adopts an unconventional detector structure design, and judges the event type based on the collected photoelectric signal, thereby eliminating or correcting the ICS event from the total events.
  • the prior art discloses a detector structure for reducing ICS events, wherein the detector is composed of an array of scintillation crystal bars, and the side of the detector array faces the center of the field of view. Through such an arrangement, the detector has the ability to read out a single ICS event.
  • each crystal array sheet needs to read out the photoelectric signal of the sheet separately, and photoelectric detectors and readout circuits need to be inserted between each crystal array sheet, so the cost of the overall detector is very high.
  • the inserted multiple sets of photoelectric detectors and readout circuits cause the effective detection volume of the detector to be greatly reduced, resulting in a very low sensitivity of the overall detector.
  • a crystal array detector comprising:
  • a crystal array the crystal array comprises a composite crystal layer, the composite crystal layer comprises a plurality of first scintillation crystals of a first type and a plurality of second scintillation crystals of a second type closely arranged in a transverse plane, the plurality of first scintillation crystals are dispersed in the plurality of second scintillation crystals, each of the plurality of first scintillation crystals has a first scintillation light decay time, each of the plurality of second scintillation crystals has a second scintillation light decay time different from the first scintillation light decay time, a side surface of each of the plurality of first scintillation crystals and the plurality of second scintillation crystals is covered with an inner reflective layer that reflects light toward the inside of the corresponding scintillation crystal, and along a longitudinal direction perpendicular to the transverse plane, the crystal array has an incident surface and an exit surface opposite to each other;
  • the array reflective layer covers the incident surface and reflects light toward the interior of the crystal array
  • the light sensor layer is optically coupled to the output surface.
  • the crystal array detector provided by the present invention, since a plurality of second scintillation crystals of different types are dispersed in a plurality of first scintillation crystals, by making the first scintillation crystals and the second scintillation crystals have different scintillation light decay times, ICS events in which energy deposition has occurred in both types of scintillation crystals can be screened out from the energy deposition events detected in the light sensor layer. Therefore, by effectively detecting and eliminating or correcting these ICS events, the proportion of remaining scattered events in the total number of events is greatly reduced, which greatly improves the signal-to-noise ratio of the reconstructed image.
  • the ability of the crystal array detector provided by the present invention to identify ICS events has a greater improvement in data accuracy for a crystal array using small-sized scintillation crystals.
  • the crystal array detector can use conventional detectors. The structural design and the cost of the whole device are at an ordinary level, so it is more practical.
  • the crystal array detector with such an arrangement has a stronger ability to identify ICS events, and the overall device has higher sensitivity and spatial resolution.
  • the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged.
  • the crystal array detector has better sensitivity and resolution in identifying ICS events.
  • the angle is 90 degrees.
  • Such a crystal array detector can already identify a larger portion of ICS events during the detection process. Therefore, when imaging using the crystal array detector provided by this embodiment, the signal-to-noise ratio of the reconstructed image can be greatly improved, thereby improving the sensitivity and spatial resolution of the imaging system.
  • the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged along both the first lateral direction and the second lateral direction.
  • the crystal array includes a plurality of composite crystal layers, wherein the first scintillation crystals in adjacent composite crystal layers are staggered; and/or the second scintillation crystals in adjacent composite crystal layers are staggered.
  • a crystal array detector with such an arrangement can reduce the influence of the depth of action of gamma photons in the scintillation crystals on the spatial resolution, thereby improving the spatial resolution of the crystal array detector.
  • the scintillation crystals can be staggered not only in the composite crystal layer, but also between the composite crystal layers, so that the crystal array detector has a stronger ability to identify ICS events.
  • such a crystal array detector can also identify cross layer crystal scattering events (CLCS), which are a type of ICS events. Therefore, the sensitivity and spatial resolution of the overall device are improved.
  • CLCS cross layer crystal scattering events
  • the composite crystal layer further includes a plurality of third scintillation crystals of the third type, the plurality of third scintillation crystals are dispersed in the plurality of first scintillation crystals and the plurality of second scintillation crystals and are closely attached to adjacent scintillation crystals, and each of the plurality of third scintillation crystals has a third scintillation light decay time that is different from the first scintillation light decay time and the second scintillation light decay time.
  • the crystal array detector having such a crystal array will have a stronger ability to identify ICS events.
  • the top corners of each type of scintillation crystal are adjacent to different types of scintillation crystals.
  • the crystal array detector designed in this way can identify ICS events more completely. This reduces the omission of ICS events in detection, thereby reducing the omission when eliminating or correcting ICS events, thereby improving the signal-to-noise ratio of the reconstruction algorithm, and the overall device has better sensitivity and spatial resolution.
  • each type of scintillator crystal is adjacent to a different type of scintillator crystal on its side.
  • the overall device has a stronger ability to identify ICS events, and improves sensitivity and spatial resolution.
  • each crystal array has a corresponding array reflective layer and a light sensor layer, and the light sensor layer corresponding to one of two adjacent crystal arrays and the array reflective layer corresponding to the other of two adjacent crystal arrays are arranged opposite to each other.
  • a crystal array detector with such an arrangement can reduce the influence of the action depth of gamma photons in the scintillation crystal on the spatial resolution, thereby improving the spatial resolution of the crystal array detector.
  • an emission imaging device includes a plurality of detectors and a processor.
  • the plurality of detectors are combined to form a detection cavity, the detection cavity is used to accommodate an object to be detected, at least one of the plurality of detectors is any one of the crystal array detectors described above, and the incident surface of the crystal array of the crystal array detector faces the detection cavity.
  • the processor is used to determine a mixed energy deposition event based on a photoelectric signal collected by a light sensor, wherein the photoelectric signal is generated based on the first scintillation light decay time and the second scintillation light decay time, and the mixed energy deposition event is an event in which energy deposition occurs in different types of scintillation crystals.
  • FIG. 1 is a cross-sectional view of a crystal array detector according to a first exemplary embodiment of the present invention
  • FIG2 is a top view of the crystal array of the crystal array detector shown in FIG1 ;
  • FIG. 3 is a top view of a crystal array of a crystal array detector according to a second exemplary embodiment of the present invention.
  • FIG. 4 is a diagram showing a crystal array of a crystal array detector according to a third exemplary embodiment of the present invention. A top view of
  • FIG. 5 is a top view of a crystal array of a crystal array detector according to a fourth exemplary embodiment of the present invention.
  • FIG. 6 is a cross-sectional view of a crystal array detector according to a fifth exemplary embodiment of the present invention.
  • FIG. 7 is a cross-sectional view of a crystal array detector according to a sixth exemplary embodiment of the present invention.
  • FIG. 8 is a top view of a crystal array of a crystal array detector according to a seventh exemplary embodiment of the present invention.
  • FIG. 9 is a top view of a crystal array of a crystal array detector according to an eighth exemplary embodiment of the present invention.
  • FIG10 is a cross-sectional view of a crystal array probe according to a ninth exemplary embodiment of the present invention.
  • FIG. 11 is a QDC-TOT schematic diagram of a data processing method for an emission imaging device.
  • the present invention provides a crystal array detector 10 , as shown in FIG1 .
  • the crystal array detector 10 may include a crystal array 100 , an array light reflecting layer 200 , and a light sensor layer 300 .
  • the crystal array 100 may include a composite crystal layer, and the composite crystal layer may include a first type of multiple first scintillation crystals 101 and a second type of multiple second scintillation crystals 102 that are closely arranged in a transverse plane.
  • a scintillation crystal refers to a crystal that can convert the energy of high-energy particles into light energy under the impact of a gamma photon.
  • the first scintillation crystal 101 may be a lutetium yttrium silicate scintillation crystal (LYSO crystal), a bismuth germanate scintillation crystal (BGO crystal), a cerium-doped lutetium silicate scintillation crystal (LSO crystal), a gadolinium silicate scintillation crystal (GSO crystal), a sodium iodide scintillation crystal (NaI crystal), or a crystal of various other materials.
  • the second scintillation crystal 102 may be a LYSO crystal, a BGO crystal, a LSO crystal, a GSO crystal, a NaI crystal, or a crystal of various other materials.
  • Each of the multiple first scintillation crystals 101 may have a first scintillation light decay time
  • each of the multiple second scintillation crystals 102 may have a first scintillation light decay time.
  • the scintillation light decay time of the first scintillation crystal 101 and the second scintillation crystal 102 can be made different by selecting different materials.
  • the scintillation light decay time is the time required for the number of scintillation photons emitted by the scintillation crystal to drop from the maximum to 1/e of the initial value after excitation.
  • the scintillation light decay time is already well known to those skilled in the art and will not be further described herein.
  • the scintillation light decay time of the LYSO crystal is 40ns
  • the scintillation light decay time of the LSO crystal is 40ns
  • the scintillation light decay time of the GSO crystal is 50ns
  • the scintillation light decay time of the BGO crystal is 300ns
  • the scintillation light decay time of the NaI crystal is 250ns.
  • the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 10 ns.
  • the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 40 ns.
  • the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 100 ns. The greater the difference in decay time of scintillation light of different types of scintillation crystals, the stronger the ability to identify ICS events mentioned below.
  • the first scintillation crystal 101 may be a scintillation crystal whose crystal material is LYSO
  • the second scintillation crystal 102 may be a scintillation crystal whose crystal material is BGO.
  • the first scintillation crystal 101 and the second scintillation crystal 102 may be prismatic, cylindrical, or other shapes.
  • the first scintillation crystal 101 and the second scintillation crystal 102 may have the same size and shape, or may have different sizes and shapes. In the embodiment shown in FIGS.
  • the first scintillation crystal 101 and the second scintillation crystal 102 are both quadrangular prisms. In the embodiment shown in FIGS. 4-5, the first scintillation crystal 101 and the second scintillation crystal 102 are both triangular prisms. In the embodiment shown in FIG. 9, the first scintillation crystal 101 and the second scintillation crystal 102 are both hexagonal prisms.
  • one of the first scintillation crystal 101 and the second scintillation crystal 102 can be a triangular prism and the other can be a quadrangular prism, so that two triangular prisms are sandwiched between every two quadrangular prisms and the two triangular prisms can be assembled into a quadrangular prism, thereby allowing the first scintillation crystal 101 and the second scintillation crystal 102 to be closely arranged.
  • a plurality of first scintillation crystals 101 and a plurality of second scintillation crystals 102 are closely arranged in a transverse plane (e.g., an XY plane).
  • the transverse plane is perpendicular to the stacking direction of the crystal array 100, the array reflective layer 200, and the light sensor layer 300, and the stacking direction is the longitudinal direction ZZ shown in FIG. 1 .
  • a plurality of first scintillation crystals 101 may be dispersed in a plurality of second scintillation crystals 102. As shown in FIG.
  • a second scintillation crystal 102 may be disposed between adjacent first scintillation crystals 101, and a first scintillation crystal 101 may be disposed between adjacent second scintillation crystals 102.
  • this does not mean that a second scintillation crystal 102 is disposed between any adjacent first scintillation crystals 101, and a first scintillation crystal 101 may be disposed between any adjacent second scintillation crystals 102.
  • FIG. 2 viewed from the Y direction, the distance between adjacent first scintillation crystals 101 and the distance between adjacent second scintillation crystals 102 are substantially the same.
  • first scintillation crystals 101 and the second scintillation crystals 102 are arranged alternately along the X direction in the figure, in other embodiments not shown, a plurality of second scintillation crystals 102 may be arranged between adjacent first scintillation crystals 101, and a plurality of first scintillation crystals 101 may be arranged between adjacent second scintillation crystals 102. In other words, the first scintillation crystals 101 and the second scintillation crystals 102 may be arranged in any regular pattern or may be arranged irregularly.
  • each of the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 may be covered with an inner reflective layer (not shown) that reflects light toward the inside of the corresponding scintillation crystal.
  • the crystal array may have a relative incident surface (upper surface in FIG1 ) and an exit surface (lower surface in FIG1 ).
  • the provision of the inner reflective layer can prevent the scintillation light generated when the scintillation crystal is hit by a gamma photon from affecting the adjacent scintillation crystal.
  • the inner reflective layer can improve the accuracy of detection.
  • the array reflective layer 200 can cover the incident surface and reflect light toward the inside of the crystal array.
  • the array reflective layer 200 can prevent the scintillation light generated by the scintillation crystal when it is hit by a gamma photon from emitting from the incident surface of the scintillation crystal.
  • the inner layer reflective layer and the array reflective layer 200 mentioned above can be formed by spraying, coating (such as spraying or silver coating) or pasting reflective materials (such as ESR reflective sheet).
  • ESR Enhanced Specular Reflector
  • ESR Enhanced Specular Reflector
  • the thickness of the ESR reflective sheet is about 40 microns, for example 38 microns.
  • the light sensor layer 300 can be optically coupled to the exit surface.
  • the light sensor layer 300 can include one or more light sensors, and the light sensors can be various types that exist or may appear in the future, such as photomultiplier tubes (PMTs), silicon photomultipliers (SiPMs), etc.
  • Optical coupling means that the scintillation light signal can be transmitted between the light sensor layer and the scintillation crystal through the exit surface.
  • the array reflective layer 200 can cooperate with the reflective layer in the layer so that the scintillation light generated by the scintillation crystal being hit by ⁇ photons can only be emitted from the exit layer, and then the scintillation light can only be transmitted to the light sensor layer 300 through the exit layer.
  • the light sensor layer 300 can receive the scintillation light signal transmitted through the exit surface, and then convert the scintillation light signal into an electrical signal, which can be used for data processing by the back-end processor, and an intuitive image can be obtained after data processing.
  • first scintillation crystals 101 dispersed in the plurality of second scintillation crystals 102
  • first scintillation crystals 101 when these first scintillation crystals 101 are hit by a gamma photon, if the hit is scattered, the particles and secondary particles generated by the scattering can deposit energy in the adjacent second scintillation crystals 102 and be detected by the optical sensor layer 300, thereby determining that an ICS event has occurred.
  • the first and second scintillation crystals 102 are struck by ⁇ photons, they have different scintillation light decay times. Therefore, an ICS event can be determined according to the photoelectric signal collected by the photosensor layer 300 .
  • an ICS event can be determined based on a QDC-TOT optoelectronic information diagram.
  • the energy deposition time occurring in different types of scintillation crystals on the QDC-TOT optoelectronic information diagram will be located in different areas on the optoelectronic information diagram, as shown in FIG11.
  • QDC Coulomb digitial convert
  • TOT time over threshold
  • TOT is the threshold time, and the unit is picosecond (ps).
  • Different materials have different scintillation light decay times. For example, the scintillation light decay times of LYSO crystal and BGO crystal are 42ns and 300ns, respectively.
  • the event detected by the optical sensor layer 300 can be preliminarily identified as a LYSO event, a BGO event, or an ICS event by utilizing the large difference in the scintillation light decay time of the two types of scintillation crystals.
  • LYSO events are concentrated in the first area I
  • BGO events are concentrated in the second area II
  • ICS events are concentrated in the third area III.
  • ICS events can be determined based on the QDC-TOT optoelectronic information map. Determined ICS events can be deleted or corrected as needed, thereby providing more accurate position information to the reconstruction algorithm.
  • determining an ICS event based on a QDC-TOT photoelectric information graph is only an example of a method for the crystal array detector 10 provided by the present invention to identify an ICS event.
  • Those skilled in the art may also use various existing or future methods to determine an ICS event based on the photoelectric signal collected by the optical sensor layer 300. Therefore, determining an ICS event is not limited to being achieved through a QDC-TOT photoelectric information graph.
  • a delayed charge integration (DCI) method may also be used to determine an ICS event based on the photoelectric signal collected by the optical sensor layer 300.
  • the crystal array detector 10 since a plurality of second scintillation crystals 102 of different types are dispersed in a plurality of first scintillation crystals 101, by making the first scintillation crystals 101 and the second scintillation crystals 102 have different scintillation light decay times, ICS events in which energy deposition has occurred in both types of scintillation crystals can be screened out from the energy deposition events detected in the light sensor layer 300. Therefore, by effectively detecting these ICS events, the proportion of the remaining scattered events in the total number of events is greatly reduced, which greatly improves the signal-to-noise ratio of the reconstructed image.
  • the recognition capability of the crystal array detector 10 provided by the present invention for ICS events has a greater improvement in data accuracy for a crystal array using small-sized scintillation crystals.
  • the crystal array detector 10 can adopt a conventional detector structure design, and the cost of the overall device is at an ordinary level, so it is also more More practical.
  • the crystal array 100 and the optical sensor layer 300 can be directly coupled by optical glue, or a light guide layer can be arranged between the two.
  • the light guide layer can be made of light guide materials, including but not limited to resin light guides, transparent glass, liquid light guides or other materials.
  • At least a portion of the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 may be arranged alternately.
  • Such an arrangement enables the crystal array detector 10 to have a higher sensitivity for detecting ICS events in the first transverse direction X-X, thereby having a better ability to identify ICS events.
  • FIG. 2 an exemplary embodiment in which the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately in the first transverse direction X-X.
  • the crystal array detector 10 having such an arrangement has a stronger ability to identify ICS events, and the sensitivity and spatial resolution of the overall device are higher.
  • FIG3 shows an exemplary embodiment in which the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately in the second transverse direction Y-Y.
  • the crystal array detector 10 with such an arrangement has better sensitivity and resolution in identifying ICS events.
  • the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately.
  • the crystal array detector 10 arranged in this way, the sensitivity and resolution of identifying ICS events are optimal.
  • the angle between the first lateral direction XX and the second lateral direction YY may be 90 degrees.
  • an exemplary embodiment is shown in which the angle between the first lateral direction XX and the second lateral direction YY is 90 degrees, and a plurality of first scintillation crystals 101 and a plurality of second scintillation crystals 102 are all arranged alternately in the first lateral direction XX and the second lateral direction YY.
  • the first scintillation crystals 101 and the second scintillation crystals 102 are arranged alternately, and each first scintillation crystal 101 is surrounded by the second scintillation crystal 102, and similarly, each second scintillation crystal 102 is surrounded by the first scintillation crystal 101.
  • the secondary particles generated by scattering will most likely enter the second scintillation crystal 102 adjacent to the first scintillation crystal 101 (as shown by arrow A in FIG. 3 ), and then deposit energy in both the first scintillation crystal 101 and the adjacent second scintillation crystal 102.
  • this type of ICS event is determined. In other words, this type of ICS event can be identified.
  • the secondary particles generated by scattering may also enter another first scintillation crystal 101 adjacent to the diagonal of the first scintillation crystal 101, as shown by arrow B in FIG3, and then deposit energy in the two first scintillation crystals 101 adjacent along the diagonal. Since this type of ICS event occurs between the same type of scintillation crystals, it cannot be identified by the QDC-TOT photoelectric information diagram.
  • the probability of this type of ICS event is much less than that of the ICS event shown by arrow A. Therefore, ideally, around each scintillation crystal, whether it is perpendicular to the direction of the edge of the scintillation crystal or the diagonal direction, it is expected to be adjacent to different types of scintillation crystals.
  • An exemplary implementation method for this idea will be provided later.
  • the crystal array detector 10 with the crystal array 100 shown in FIG3 can already identify a larger part of ICS events during the detection process. Therefore, when the crystal array detector 10 provided in this embodiment is used for imaging, the signal-to-noise ratio of the reconstructed image can be greatly improved, thereby improving the sensitivity and spatial resolution of the imaging system.
  • FIG4 shows another embodiment according to the present application.
  • the cross-sections of the first scintillation crystal 101 and the second scintillation crystal 102 are both isosceles right triangles. And for each side of the isosceles right triangle, it is adjacent to a different type of scintillation crystal, and only the vertex is adjacent to the same type of scintillation crystal.
  • the angle between the first transverse direction X-X and the second transverse direction Y-Y is not 90 degrees.
  • the angle between the first transverse direction X-X and the second transverse direction Y-Y is 45 degrees.
  • the first scintillation crystal 101 and the second scintillation crystal 102 are also arranged alternately. That is to say, in this embodiment, the first scintillation crystal 101 and the second scintillation crystal 102 can be arranged alternately in more directions. In the crystal array detector 10 using the crystal array 100, a larger portion of ICS events can also be identified.
  • FIG5 shows another embodiment in which the cross-sections of the first scintillation crystal 101 and the second scintillation crystal 102 are both isosceles right triangles.
  • first scintillation crystals 101 and the second scintillation crystals 102 are alternately arranged along a first lateral direction X-X and a second lateral direction Y-Y that are perpendicular to each other.
  • FIG4 only shows an embodiment in which the angle between the first lateral direction X-X and the second lateral direction Y-Y is not 90 degrees.
  • the angle between the first lateral direction X-X and the second lateral direction Y-Y may also have other values.
  • the crystal array 100 may include a plurality of composite crystal layers.
  • the crystal array 100 includes two composite crystal layers, each of which includes alternately arranged The first scintillation crystal 101 and the second scintillation crystal 102.
  • the arrangement of the first scintillation crystal 101 and the second scintillation crystal 102 in the two composite crystal layers is the same.
  • the arrangement of the scintillation crystals in the two composite crystal layers may also be different.
  • the first scintillation crystals 101 in adjacent composite crystal layers are staggered, and the second scintillation crystals 102 in adjacent composite crystal layers are also staggered.
  • the crystal array detector 10 with such an arrangement can reduce the influence of the depth of action of ⁇ photons in the scintillation crystals on the spatial resolution, and improve the spatial resolution of the crystal array detector 10.
  • the scintillation crystals can be staggered not only in the composite crystal layer, but also between the composite crystal layers, so that the crystal array detector 10 has a stronger ability to identify ICS events.
  • the crystal array detector 10 can also identify inter-layer crystal scattering events, and CLCS events are a type of ICS events. Therefore, the sensitivity and spatial resolution of the overall device are improved.
  • only one type of scintillation crystals can be staggered in adjacent composite crystal layers. In this case, other types (eg, the second type and the third type) of scintillator crystals may not be completely staggered between adjacent composite crystal layers.
  • the crystal array 100 may also include a single crystal layer.
  • the upper layer in the crystal array 100 is a composite crystal layer, and the lower layer is a single crystal layer, and the single crystal layer may include only one type of scintillation crystal 104.
  • the scintillation crystal 104 may be a crystal array or a continuous crystal, and the continuous crystal refers to a whole piece of scintillation crystal.
  • the scintillation crystal 104 may be of the same type as the first scintillation crystal 101, or of the same type as the second scintillation crystal 102, or of different types from both the first scintillation crystal 101 and the second scintillation crystal 102. In such a crystal array, a part of the ICS events occurring in the upper layer can be identified, but the ICS events in the lower layer may not be identified, but in any case, the signal-to-noise ratio of the reconstructed image can still be improved.
  • the crystal array detector provided by the present invention may include two or more layers of crystal arrays, and as long as at least one layer thereof is a composite crystal layer, it is covered within the protection scope of the present application.
  • the position of the composite crystal layer in the entire detector may not be limited, for example, it may be located at the bottom layer close to the light sensor layer 300, and/or the top layer away from the light sensor layer 300, and/or the middle layer therebetween.
  • the composite crystal layer may further include a plurality of third scintillation crystals 103 of a third type, and the plurality of third scintillation crystals 103 may be dispersed in the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 and may be closely attached to adjacent scintillation crystals.
  • the third scintillation crystals 103 may have a third scintillation light decay time that is different from the first scintillation light decay time and the second scintillation light decay time.
  • the first scintillation light decay time, the second scintillation light decay time and the third scintillation light decay time may be different from each other.
  • the third scintillation crystal 103 can be made of a scintillation crystal material different from that of the first scintillation crystal 101 and the second scintillation crystal 102. There may be three situations in which the light sensor layer 300 has energy deposition in two different types of scintillation crystals in an event in which a ⁇ photon is emitted to the crystal array detector.
  • each scintillation crystal has only two diagonally adjacent scintillation crystals of the same type. Therefore, a larger number of ICS events can be identified, so the crystal array detector 10 with such a crystal array 100 will have a stronger ability to identify ICS events.
  • the above-mentioned drawings show embodiments used as references for the present application, but this does not mean that the present application can only be implemented in this form. In other embodiments not shown, the present application may also have various other similar forms, which will not be described in detail here.
  • FIG9 shows the arrangement of a crystal array according to another embodiment of the present application.
  • the crystal array 100 different types of first scintillation crystals 101, second scintillation crystals 102 and third scintillation crystals 103 are included, and the cross-sections of the first scintillation crystals 101, the second scintillation crystals 102 and the third scintillation crystals 103 are all regular hexagons. Moreover, the sides and vertices of each regular hexagon can be adjacent to different types of scintillation crystals. In the crystal array detector 10 with such an arrangement, each scintillation crystal is surrounded by different types of scintillation crystals.
  • the gamma photon first hits the first scintillation crystal 101 as an example, and the secondary particles generated by the gamma photon may enter one or more surrounding scintillation crystals. Since the scintillation light decay time of the surrounding one or more scintillation crystals is different from the scintillation light decay time of the first scintillation crystal 101, these ICS events can be identified.
  • the crystal array detector 10 designed in this way identifies ICS events more completely and comprehensively, reduces omissions of ICS events in detection, and further reduces omissions when identifying ICS events, thereby improving the signal-to-noise ratio of the reconstruction algorithm, and the overall device has better sensitivity and spatial resolution.
  • the scintillation crystals may have various other possible shapes, which is applicable to the case where the composite crystal layer includes two types of scintillation crystals, and also applicable to the case where there are more types of scintillation crystals.
  • different types of scintillation crystals may have the same shape or different shapes.
  • FIG10 shows another embodiment according to the present application.
  • a crystal array 100 There are multiple crystal arrays 100 and they are arranged in sequence along the longitudinal direction, and each crystal array has a corresponding array reflective layer 200 and a light sensor layer 300.
  • the light sensor layer 300 corresponding to one of the two adjacent crystal arrays 100 and the array reflective layer 200 corresponding to the other of the two adjacent crystal arrays 100 are arranged opposite to each other. That is to say, the light sensor layer 300 coupled to the upper crystal array 100 and the array reflective layer 200 covered on the lower crystal array 100 are opposite to each other.
  • the light sensor layer 300 coupled to the upper crystal array 100 and the array reflective layer 200 covered on the lower crystal array 100 are attached to each other. In other embodiments not shown, they may also be spaced apart. In this case, the signal readout circuit of the upper light sensor may be placed at the interval. If the array reflective layer 200, the crystal array 100 and the light sensor layer 300 are considered as a repeating unit, the crystal array detector 10 may include one or more of these repeating units. The crystal array detector 10 with such an arrangement can reduce the influence of the action depth of the gamma photons in the scintillation crystal on the spatial resolution, and improve the spatial resolution of the crystal array detector 10. It should be noted that the crystal array 100 mentioned in FIG. 10 may be any one of the ones mentioned above.
  • the scintillation crystals in two adjacent crystal arrays may have the same arrangement.
  • Two adjacent crystal arrays are respectively connected to two optical sensor layers 300, and the two optical sensor layers 300 respectively detect whether energy deposition occurs in the two crystal arrays. Therefore, it can be considered that both optical sensor layers 300 identify ICS events from a large number of energy deposition events.
  • the scintillation crystals in two adjacent crystal arrays may also have different arrangements.
  • a plurality of first scintillation crystals in one of the two adjacent crystal arrays are staggered with a plurality of first scintillation crystals in another of the two adjacent crystal arrays.
  • a plurality of first scintillation crystals 101 in one of the two adjacent crystal arrays may be staggered with a plurality of first scintillation crystals 101 in another of the two adjacent crystal arrays, or may be aligned.
  • the second scintillation crystals 102 in the two crystal arrays may be staggered or aligned.
  • the present invention also provides an emission imaging device.
  • the emission imaging device may include a plurality of detectors, and the plurality of detectors may be combined to form a detection cavity, and the detection cavity may be used to accommodate an object to be detected. At least a portion of these detectors may be any of the crystal array detectors 10 described above.
  • the incident surface of the crystal array 100 of the crystal array detector 10 may face the detection cavity.
  • the data of the plurality of detectors may be combined to obtain more comprehensive and complete three-dimensional information of the object to be detected.
  • Other detectors may be common detectors commonly used in PET imaging. Common detectors and crystal array detectors 10 may be arranged in any suitable manner.
  • the detection cavity can be cylindrical.
  • the crystal array detector 10 is arranged in a ring around the detection cavity.
  • the object to be detected can lie flat and enter the detection cavity.
  • the cylindrical detection cavity structure is also simpler and easy to implement.
  • the detection cavity can also have other shapes, such as an oblate cylindrical shape or a rectangular parallelepiped shape.
  • the emission imaging device may further include a processor, which may be used to determine a mixed energy deposition event based on the photoelectric signal collected by the light sensor layer 300, wherein the mixed energy deposition event is an event in which energy deposition occurs in different types of scintillation crystals.
  • the mixed energy deposition event is an ICS event that can be identified. The method for determining an ICS event has been described above and will not be repeated here.

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Abstract

A crystal array detector (10) and an emission imaging device. The crystal array detector (10) comprises a crystal array (100), an array reflective layer (200), and a light sensor layer (300). The crystal array (100) comprises a composite crystal layer. The composite crystal layer comprises a plurality of first scintillation crystals (101) of a first type and a plurality of second scintillation crystals (102) of a second type closely arranged in a transverse plane. The plurality of first scintillation crystals (101) are dispersed in the plurality of second scintillation crystals (102). Each of the plurality of first scintillation crystals (101) has a first scintillation light attenuation time, and each of the plurality of second scintillation crystals (102) has a second scintillation light attenuation time different from the first scintillation light attenuation time. Due to the use of the plurality of first scintillation crystals (101) and the plurality of second scintillation crystals (102) having different scintillation light attenuation time, energy deposition events detected in the light sensor layer (300) can be screened to identify ICS events characterized by the presence of energy deposition in both types of scintillation crystals. The signal-to-noise ratio of the reconstructed image can be greatly improved by removing or correcting the ICS event.

Description

晶体阵列探测器和发射成像设备Crystal array detectors and emission imaging equipment 技术领域Technical Field
本发明涉及发射成像系统，具体地，涉及一种晶体阵列探测器以及具有该晶体阵列探测器的发射成像设备。The present invention relates to an emission imaging system, in particular to a crystal array detector and an emission imaging device having the crystal array detector.
背景技术Background technique
发射型计算机断层成像(Emission Computed Tomography，ECT)是一种能显示放射性核素在生物体内各层面的分布及立体分布影像的显像技术，该技术利用放射性核素的示踪原理，通过检测放射性核素衰变发射的射线，经过数据处理形成图像。ECT目前分为两大类，一类用于探测能够发射γ射线的放射性核素在生物体内的分布，称为单光子发射型计算机断层成像(Single Photon Emission Computed Tomography，SPECT)；另一类用于探测能够发射正电子的放射性核素的湮灭辐射，称为正电子发射型计算机断层成像(Positron Emission Computed Tomography，PET)。其中，PET成像已在医学影像学相关领域得到广泛应用。Emission Computed Tomography (ECT) is an imaging technology that can display the distribution of radionuclides at all levels in the body and three-dimensional distribution images. This technology uses the tracer principle of radionuclides to detect the rays emitted by the decay of radionuclides and forms images through data processing. ECT is currently divided into two categories. One is used to detect the distribution of radionuclides that can emit gamma rays in the body, called Single Photon Emission Computed Tomography (SPECT); the other is used to detect the annihilation radiation of radionuclides that can emit positrons, called Positron Emission Computed Tomography (PET). Among them, PET imaging has been widely used in related fields of medical imaging.
PET成像探测正电子湮灭时发射的两个方向相反的γ光子，并通过计算机重建正电子示踪剂在生物体内的三维分布。但是，在探测过程中，γ光子撞击闪烁晶体时很可能会发生晶体间散射事件(Inter Crystal Scatter，ICS)，ICS事件的存在会严重降低重建算法的信噪比。PET imaging detects two gamma photons emitted in opposite directions when positrons are annihilated, and reconstructs the three-dimensional distribution of positron tracers in the body through computers. However, during the detection process, inter-crystal scattering events (ICS) are likely to occur when gamma photons hit scintillation crystals. The presence of ICS events will seriously reduce the signal-to-noise ratio of the reconstruction algorithm.
典型地，在生物医学研究中，临床前疾病模型的大部分以小鼠作为动物模型，来模拟人类健康与疾病状态，专用于小动物成像的临床前PET成像技术是分子生物学向临床转化的重要工具。因为小动物的体积和质量比人类小很多，所以为了获取等效于人体PET成像所能得到的图像细节，用于小动物的PET成像需要更高的系统灵敏度和空间分辨率。Typically, in biomedical research, most preclinical disease models use mice as animal models to simulate human health and disease states. Preclinical PET imaging technology dedicated to small animal imaging is an important tool for the transformation of molecular biology to the clinic. Because small animals are much smaller in size and mass than humans, in order to obtain image details equivalent to those that can be obtained by human PET imaging, PET imaging for small animals requires higher system sensitivity and spatial resolution.
小动物PET成像的高分辨率是基于较小的闪烁晶体尺寸实现的，而对于较小尺寸的闪烁晶体，晶体间散射事件(Inter Crystal Scatter，ICS)会向重建图像中引入较大的噪声，降低重建图像的信噪比，影响研究者基于图像作出判断。因此，在PET成像中识别一定数量的ICS事件，并将他们从事件总数中剔除或矫正，可以有效提升重建图像的信噪比，使成像结果 更加准确。The high resolution of small animal PET imaging is achieved based on the smaller size of scintillation crystals. For smaller scintillation crystals, inter-crystal scattering events (ICS) will introduce greater noise into the reconstructed image, reducing the signal-to-noise ratio of the reconstructed image and affecting the judgment made by researchers based on the image. Therefore, identifying a certain number of ICS events in PET imaging and removing or correcting them from the total number of events can effectively improve the signal-to-noise ratio of the reconstructed image and make the imaging results more accurate. more precise.
现有技术为了从总事件中筛查出ICS事件，往往采用非常规探测器结构设计，并基于采集到的光电信号判断事件类型，进而将ICS事件从总事件中剔除或矫正。现有技术公开了一种用于减少ICS事件的探测器结构，该探测器由闪烁晶体条组成阵列，并以探测器阵列的侧面面向视野中心。通过这样的布置，探测器具有读出单个ICS事件的能力。但是，这样的探测器结构中每片晶体阵列片都需要对该片的光电信号进行单独读出，各个晶体阵列片之间均需要插入光电探测器和读出电路，因此整体探测器的造价非常高。而且所插入的多套光电探测器和读出电路导致探测器的有效探测体积大大减少，导致整体探测器灵敏度非常低。In order to screen out ICS events from the total events, the prior art often adopts an unconventional detector structure design, and judges the event type based on the collected photoelectric signal, thereby eliminating or correcting the ICS event from the total events. The prior art discloses a detector structure for reducing ICS events, wherein the detector is composed of an array of scintillation crystal bars, and the side of the detector array faces the center of the field of view. Through such an arrangement, the detector has the ability to read out a single ICS event. However, in such a detector structure, each crystal array sheet needs to read out the photoelectric signal of the sheet separately, and photoelectric detectors and readout circuits need to be inserted between each crystal array sheet, so the cost of the overall detector is very high. Moreover, the inserted multiple sets of photoelectric detectors and readout circuits cause the effective detection volume of the detector to be greatly reduced, resulting in a very low sensitivity of the overall detector.
发明内容Summary of the invention
根据本发明的一个方面，提供一种晶体阵列探测器，包括：According to one aspect of the present invention, there is provided a crystal array detector, comprising:
晶体阵列，晶体阵列包括复合晶体层，复合晶体层包括在横向平面内密贴排列的第一类型的多个第一闪烁晶体和第二类型的多个第二闪烁晶体，多个第一闪烁晶体分散在多个第二闪烁晶体中，多个第一闪烁晶体中的每个具有第一闪烁光衰减时间，多个第二闪烁晶体中的每个具有不同于第一闪烁光衰减时间的第二闪烁光衰减时间，多个第一闪烁晶体和多个第二闪烁晶体中的每个的侧面都覆盖有朝向对应的闪烁晶体的内部反光的层内反光层，沿垂直于横向平面的纵向方向，晶体阵列具有相对的入射面和出射面；A crystal array, the crystal array comprises a composite crystal layer, the composite crystal layer comprises a plurality of first scintillation crystals of a first type and a plurality of second scintillation crystals of a second type closely arranged in a transverse plane, the plurality of first scintillation crystals are dispersed in the plurality of second scintillation crystals, each of the plurality of first scintillation crystals has a first scintillation light decay time, each of the plurality of second scintillation crystals has a second scintillation light decay time different from the first scintillation light decay time, a side surface of each of the plurality of first scintillation crystals and the plurality of second scintillation crystals is covered with an inner reflective layer that reflects light toward the inside of the corresponding scintillation crystal, and along a longitudinal direction perpendicular to the transverse plane, the crystal array has an incident surface and an exit surface opposite to each other;
阵列反光层，阵列反光层覆盖在入射面上且朝向晶体阵列的内部反光；以及an array reflective layer, the array reflective layer covers the incident surface and reflects light toward the interior of the crystal array; and
光传感器层，光传感器层光耦合至出射面。The light sensor layer is optically coupled to the output surface.
在本发明提供的晶体阵列探测器中，由于在多个第一闪烁晶体中分散有不同类型的多个第二闪烁晶体，通过使第一闪烁晶体和第二闪烁晶体具有不同的闪烁光衰减时间，可以在光传感器层中检测到的能量沉积事件中筛选出在两种类型的闪烁晶体内都发生过能量沉积的ICS事件。因此，通过有效地检测并剔除或矫正这些ICS事件，剩余散射事件占总事件数的比例大幅下降，这会极大提升重建图像的信噪比。晶体阵列中闪烁晶体的横截面越小，所识别的ICS事件占总事件的份额越大，本发明提供的晶体阵列探测器对ICS事件的识别能力对于采用小尺寸闪烁晶体的晶体阵列来说，数据准确度的提升更大。此外，晶体阵列探测器可以采用常规探测器 结构设计，整体装置的造价为普通水平，因此也更加实用。In the crystal array detector provided by the present invention, since a plurality of second scintillation crystals of different types are dispersed in a plurality of first scintillation crystals, by making the first scintillation crystals and the second scintillation crystals have different scintillation light decay times, ICS events in which energy deposition has occurred in both types of scintillation crystals can be screened out from the energy deposition events detected in the light sensor layer. Therefore, by effectively detecting and eliminating or correcting these ICS events, the proportion of remaining scattered events in the total number of events is greatly reduced, which greatly improves the signal-to-noise ratio of the reconstructed image. The smaller the cross-section of the scintillation crystal in the crystal array, the greater the proportion of the identified ICS events in the total events. The ability of the crystal array detector provided by the present invention to identify ICS events has a greater improvement in data accuracy for a crystal array using small-sized scintillation crystals. In addition, the crystal array detector can use conventional detectors. The structural design and the cost of the whole device are at an ordinary level, so it is more practical.
示例性地，沿着横向平面内的第一横向方向，多个第一闪烁晶体和多个第二闪烁晶体中的至少一部分交替排列。具有这样布置的晶体阵列探测器，识别ICS事件的能力更强，整体装置的灵敏度和空间分辨率更高。For example, along the first transverse direction in the transverse plane, at least a portion of the plurality of first scintillation crystals and the plurality of second scintillation crystals are arranged alternately. The crystal array detector with such an arrangement has a stronger ability to identify ICS events, and the overall device has higher sensitivity and spatial resolution.
示例性地，沿着所述第一横向方向，所述多个第一闪烁晶体和所述多个第二闪烁晶体完全交替排列。Exemplarily, along the first transverse direction, the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged.
示例性地，沿着横向平面内的第二横向方向，多个第一闪烁晶体和多个第二闪烁晶体中的至少一部分交替排列，其中第二横向方向与第一横向方向之间具有夹角。具有这样布置的晶体阵列探测器，识别ICS事件的灵敏度和分辨率都更好。Exemplarily, along a second transverse direction in the transverse plane, at least a portion of the plurality of first scintillation crystals and the plurality of second scintillation crystals are alternately arranged, wherein the second transverse direction is at an angle to the first transverse direction. With such an arrangement, the crystal array detector has better sensitivity and resolution in identifying ICS events.
示例性地，夹角为90度。这样的晶体阵列探测器，已经能够在探测过程中识别出更大部分的ICS事件。因此，采用该实施例提供的晶体阵列探测器成像时，可以极大地提升重建图像的信噪比，进而提高成像系统的灵敏度和空间分辨率。Exemplarily, the angle is 90 degrees. Such a crystal array detector can already identify a larger portion of ICS events during the detection process. Therefore, when imaging using the crystal array detector provided by this embodiment, the signal-to-noise ratio of the reconstructed image can be greatly improved, thereby improving the sensitivity and spatial resolution of the imaging system.
示例性地，多个第一闪烁晶体和多个第二闪烁晶体沿着第一横向方向和第二横向方向均完全交替排列。Exemplarily, the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged along both the first lateral direction and the second lateral direction.
示例性地，晶体阵列包括多个复合晶体层，其中，相邻的复合晶体层中的第一闪烁晶体错开设置；和/或相邻的复合晶体层中的第二闪烁晶体错开设置。具有这样布置的晶体阵列探测器可以降低γ光子在闪烁晶体内作用深度对空间分辨率的影响，提高了晶体阵列探测器的空间分辨率。闪烁晶体不仅可以在复合晶体层内交错排列，在复合晶体层之间也可以交错排列，这样晶体阵列探测器识别ICS事件的能力更强，特别地，这样晶体阵列探测器还可以识别层间晶体间散射事件(Cross Layer Crystal Scatter，CLCS)，CLCS事件是ICS事件的一种。因此提高了整体装置的灵敏度和空间分辨率。Exemplarily, the crystal array includes a plurality of composite crystal layers, wherein the first scintillation crystals in adjacent composite crystal layers are staggered; and/or the second scintillation crystals in adjacent composite crystal layers are staggered. A crystal array detector with such an arrangement can reduce the influence of the depth of action of gamma photons in the scintillation crystals on the spatial resolution, thereby improving the spatial resolution of the crystal array detector. The scintillation crystals can be staggered not only in the composite crystal layer, but also between the composite crystal layers, so that the crystal array detector has a stronger ability to identify ICS events. In particular, such a crystal array detector can also identify cross layer crystal scattering events (CLCS), which are a type of ICS events. Therefore, the sensitivity and spatial resolution of the overall device are improved.
示例性地，复合晶体层中还包括第三类型的多个第三闪烁晶体，多个第三闪烁晶体分散在多个第一闪烁晶体和多个第二闪烁晶体中且与相邻的闪烁晶体密贴，多个第三闪烁晶体中的每个都具有不同于第一闪烁光衰减时间和第二闪烁光衰减时间的第三闪烁光衰减时间。这样可以识别出更大量的ICS事件，因此具有这种晶体阵列的晶体阵列探测器识别ICS事件的能力也会更强。Exemplarily, the composite crystal layer further includes a plurality of third scintillation crystals of the third type, the plurality of third scintillation crystals are dispersed in the plurality of first scintillation crystals and the plurality of second scintillation crystals and are closely attached to adjacent scintillation crystals, and each of the plurality of third scintillation crystals has a third scintillation light decay time that is different from the first scintillation light decay time and the second scintillation light decay time. In this way, a greater number of ICS events can be identified, and thus the crystal array detector having such a crystal array will have a stronger ability to identify ICS events.
示例性地，在复合晶体层中，每种类型的闪烁晶体的顶角都邻接不同类型的闪烁晶体。这样设计的晶体阵列探测器识别的ICS事件更加完整全 面，减少了探测中对于ICS事件的疏漏，进而减少了剔除或矫正ICS事件时的遗漏，因此提高了重建算法的信噪比，整体装置具有更好的灵敏度和空间分辨率。For example, in the composite crystal layer, the top corners of each type of scintillation crystal are adjacent to different types of scintillation crystals. The crystal array detector designed in this way can identify ICS events more completely. This reduces the omission of ICS events in detection, thereby reducing the omission when eliminating or correcting ICS events, thereby improving the signal-to-noise ratio of the reconstruction algorithm, and the overall device has better sensitivity and spatial resolution.
示例性地，在复合晶体层中，每种类型的闪烁晶体的侧面都邻接不同类型的闪烁晶体。这样，整体装置识别ICS事件的能力更强，提升了灵敏度和空间分辨率。For example, in the composite crystal layer, each type of scintillator crystal is adjacent to a different type of scintillator crystal on its side. In this way, the overall device has a stronger ability to identify ICS events, and improves sensitivity and spatial resolution.
示例性地，在如上文所述的任一种晶体阵列探测器中，晶体阵列为多个且沿着纵向方向依次设置，每个晶体阵列都具有对应的阵列反光层和光传感器层，相邻两个晶体阵列中的一个所对应的光传感器层与相邻两个晶体阵列中的另一个所对应的阵列反光层彼此相对设置。具有这样布置的晶体阵列探测器可以降低γ光子在闪烁晶体内作用深度对空间分辨率的影响，提高了晶体阵列探测器的空间分辨率。For example, in any of the crystal array detectors described above, there are multiple crystal arrays and they are arranged in sequence along the longitudinal direction, each crystal array has a corresponding array reflective layer and a light sensor layer, and the light sensor layer corresponding to one of two adjacent crystal arrays and the array reflective layer corresponding to the other of two adjacent crystal arrays are arranged opposite to each other. A crystal array detector with such an arrangement can reduce the influence of the action depth of gamma photons in the scintillation crystal on the spatial resolution, thereby improving the spatial resolution of the crystal array detector.
根据本发明的另一个方面，提供一种发射成像设备。发射成像设备包括多个探测器和处理器。多个探测器合围形成检测腔体，检测腔体用于容纳待测对象，多个探测器中的至少一个为如上文中所述的任一种晶体阵列探测器，晶体阵列探测器的晶体阵列的入射面朝向检测腔体。处理器用于根据光传感器采集的光电信号确定混合能量沉积事件，其中，光电信号基于所述第一闪烁光衰减时间和所述第二闪烁光衰减时间生成，混合能量沉积事件为在不同类型的闪烁晶体内都发生能量沉积的事件。According to another aspect of the present invention, an emission imaging device is provided. The emission imaging device includes a plurality of detectors and a processor. The plurality of detectors are combined to form a detection cavity, the detection cavity is used to accommodate an object to be detected, at least one of the plurality of detectors is any one of the crystal array detectors described above, and the incident surface of the crystal array of the crystal array detector faces the detection cavity. The processor is used to determine a mixed energy deposition event based on a photoelectric signal collected by a light sensor, wherein the photoelectric signal is generated based on the first scintillation light decay time and the second scintillation light decay time, and the mixed energy deposition event is an event in which energy deposition occurs in different types of scintillation crystals.
在发明内容中引入了一系列简化形式的概念，这将在具体实施方式部分中进一步详细说明。本发明内容部分并不意味着要试图限定出所要求保护的技术方案的关键特征和必要技术特征，更不意味着试图确定所要求保护的技术方案的保护范围。A series of simplified concepts are introduced in the summary of the invention, which will be further described in detail in the detailed description. The summary of the invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.
以下结合附图，详细说明本发明的优点和特征。The advantages and features of the present invention are described in detail below with reference to the accompanying drawings.
附图说明BRIEF DESCRIPTION OF THE DRAWINGS
本发明的下列附图在此作为本发明的一部分用于理解本发明。附图中示出了本发明的实施方式及其描述，用来解释本发明的原理。在附图中，The following drawings of the present invention are used as part of the present invention for understanding the present invention. The drawings show the embodiments of the present invention and their descriptions, and are used to explain the principles of the present invention. In the drawings,
图1为根据本发明的第一示例性实施例的晶体阵列探测器的剖视图；1 is a cross-sectional view of a crystal array detector according to a first exemplary embodiment of the present invention;
图2为图1所示的晶体阵列探测器的晶体阵列的俯视图；FIG2 is a top view of the crystal array of the crystal array detector shown in FIG1 ;
图3为根据本发明的第二示例性实施例的晶体阵列探测器的晶体阵列的俯视图；3 is a top view of a crystal array of a crystal array detector according to a second exemplary embodiment of the present invention;
图4为根据本发明的第三示例性实施例的晶体阵列探测器的晶体阵列 的俯视图；FIG. 4 is a diagram showing a crystal array of a crystal array detector according to a third exemplary embodiment of the present invention. A top view of
图5为根据本发明的第四示例性实施例的晶体阵列探测器的晶体阵列的俯视图；5 is a top view of a crystal array of a crystal array detector according to a fourth exemplary embodiment of the present invention;
图6为根据本发明的第五示例性实施例的晶体阵列探测器的剖视图；6 is a cross-sectional view of a crystal array detector according to a fifth exemplary embodiment of the present invention;
图7为根据本发明的第六示例性实施例的晶体阵列探测器的剖视图；7 is a cross-sectional view of a crystal array detector according to a sixth exemplary embodiment of the present invention;
图8为根据本发明的第七示例性实施例的晶体阵列探测器的晶体阵列的俯视图；8 is a top view of a crystal array of a crystal array detector according to a seventh exemplary embodiment of the present invention;
图9为根据本发明的第八示例性实施例的晶体阵列探测器的晶体阵列的俯视图；9 is a top view of a crystal array of a crystal array detector according to an eighth exemplary embodiment of the present invention;
图10为根据本发明的第九示例性实施例的晶体阵列探测器的剖视图；以及FIG10 is a cross-sectional view of a crystal array probe according to a ninth exemplary embodiment of the present invention; and
图11为发射成像设备的一种数据处理方法的QDC-TOT示意图。FIG. 11 is a QDC-TOT schematic diagram of a data processing method for an emission imaging device.
具体实施方式Detailed ways
在下文的描述中，给出了大量具体的细节以便提供对本发明更为彻底的理解。然而，对于本领域技术人员来说显而易见的是，本发明可以无需一个或多个这些细节而得以实施。在其他的例子中，为了避免与本发明发生混淆，对于本领域公知的一些技术特征未进行描述。In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.
为了彻底了解本发明，将在下列的描述中提出详细的结构。显然，本发明的实施例并不限定于本领域的技术人员所熟习的特殊细节。本发明的较佳实施例详细描述如下，然而除了这些详细描述外，本发明还可以具有其他实施方式。In order to fully understand the present invention, a detailed structure will be proposed in the following description. Obviously, the embodiments of the present invention are not limited to the specific details familiar to those skilled in the art. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention can also have other embodiments.
本发明提供一种晶体阵列探测器10，如图1所示。晶体阵列探测器10可以包括晶体阵列100、阵列反光层200和光传感器层300。The present invention provides a crystal array detector 10 , as shown in FIG1 . The crystal array detector 10 may include a crystal array 100 , an array light reflecting layer 200 , and a light sensor layer 300 .
晶体阵列100可以包括复合晶体层，复合晶体层可以包括在横向平面内密贴排列的第一类型的多个第一闪烁晶体101和第二类型的多个第二闪烁晶体102。闪烁晶体指的是在γ光子的撞击下，能将高能粒子的能量转化为光能的晶体。第一闪烁晶体101可以是硅酸钇镥闪烁晶体(LYSO晶体)、锗酸铋闪烁晶体(BGO晶体)、掺铈硅酸镥闪烁晶体(LSO晶体)、硅酸钆闪烁晶体(GSO晶体)、碘化钠闪烁晶体(NaI晶体)或其他多种材料的晶体。第二闪烁晶体102可以是LYSO晶体、BGO晶体、LSO晶体、GSO晶体、NaI晶体或其他多种材料的晶体。多个第一闪烁晶体101中的每个可以具有第一闪烁光衰减时间，多个第二闪烁晶体102中的每个可以 具有不同于第一闪烁光衰减时间的第二闪烁光衰减时间。通过选择不同的材料可以使第一闪烁晶体101和第二闪烁晶体102的闪烁光衰减时间不同。闪烁光衰减时间为闪烁晶体激发后发射闪烁光子的数量从最大下降到初始值的1/e时所需的时间。闪烁光衰减时间已经为本领域技术人员所熟知，本文不在进一步详述。LYSO晶体的闪烁光衰减时间为40ns，LSO晶体的闪烁光衰减时间为40ns，GSO晶体的闪烁光衰减时间为50ns、BGO晶体的闪烁光衰减时间为300ns，NaI晶体的闪烁光衰减时间为250ns。The crystal array 100 may include a composite crystal layer, and the composite crystal layer may include a first type of multiple first scintillation crystals 101 and a second type of multiple second scintillation crystals 102 that are closely arranged in a transverse plane. A scintillation crystal refers to a crystal that can convert the energy of high-energy particles into light energy under the impact of a gamma photon. The first scintillation crystal 101 may be a lutetium yttrium silicate scintillation crystal (LYSO crystal), a bismuth germanate scintillation crystal (BGO crystal), a cerium-doped lutetium silicate scintillation crystal (LSO crystal), a gadolinium silicate scintillation crystal (GSO crystal), a sodium iodide scintillation crystal (NaI crystal), or a crystal of various other materials. The second scintillation crystal 102 may be a LYSO crystal, a BGO crystal, a LSO crystal, a GSO crystal, a NaI crystal, or a crystal of various other materials. Each of the multiple first scintillation crystals 101 may have a first scintillation light decay time, and each of the multiple second scintillation crystals 102 may have a first scintillation light decay time. A second scintillation light decay time different from the first scintillation light decay time. The scintillation light decay time of the first scintillation crystal 101 and the second scintillation crystal 102 can be made different by selecting different materials. The scintillation light decay time is the time required for the number of scintillation photons emitted by the scintillation crystal to drop from the maximum to 1/e of the initial value after excitation. The scintillation light decay time is already well known to those skilled in the art and will not be further described herein. The scintillation light decay time of the LYSO crystal is 40ns, the scintillation light decay time of the LSO crystal is 40ns, the scintillation light decay time of the GSO crystal is 50ns, the scintillation light decay time of the BGO crystal is 300ns, and the scintillation light decay time of the NaI crystal is 250ns.
示例性地，不同类型的闪烁晶体的闪烁光衰减时间之差可以大于或等于10ns。较佳地，不同类型的闪烁晶体的闪烁光衰减时间之差可以大于或等于40ns。更佳地，不同类型的闪烁晶体的闪烁光衰减时间之差可以大于或等于100ns。不同类型的闪烁晶体的闪烁光衰减时间之差越大，对下文将提到的ICS事件的识别能力越强。For example, the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 10 ns. Preferably, the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 40 ns. More preferably, the difference in decay time of scintillation light of different types of scintillation crystals may be greater than or equal to 100 ns. The greater the difference in decay time of scintillation light of different types of scintillation crystals, the stronger the ability to identify ICS events mentioned below.
例如，第一闪烁晶体101可以是晶体材料为LYSO的闪烁晶体，而第二闪烁晶体102可以是晶体材料为BGO的闪烁晶体。优选地，第一闪烁光衰减时间和第二闪烁光衰减时间差别越大越好。第一闪烁晶体101和第二闪烁晶体102可以呈棱柱形、圆柱形或其他多种形状。第一闪烁晶体101和第二闪烁晶体102可以具有相同的尺寸、形状，也可以分别具有不同的尺寸、形状。如图1-2所示的实施例中，第一闪烁晶体101和第二闪烁晶体102均为四棱柱。在图4-5所示的实施例中，第一闪烁晶体101和第二闪烁晶体102均为三棱柱。在图9所示的实施例中，第一闪烁晶体101和第二闪烁晶体102均为六棱柱。在未示出的其他实施例中，第一闪烁晶体101和第二闪烁晶体102中的一个可以为三棱柱而另一个为四棱柱，这样在每两个四棱柱之间夹设两个三棱柱且这两个三棱柱能够拼合成四棱柱，由此可以使得第一闪烁晶体101和第二闪烁晶体102密贴排列。For example, the first scintillation crystal 101 may be a scintillation crystal whose crystal material is LYSO, and the second scintillation crystal 102 may be a scintillation crystal whose crystal material is BGO. Preferably, the greater the difference between the first scintillation light attenuation time and the second scintillation light attenuation time, the better. The first scintillation crystal 101 and the second scintillation crystal 102 may be prismatic, cylindrical, or other shapes. The first scintillation crystal 101 and the second scintillation crystal 102 may have the same size and shape, or may have different sizes and shapes. In the embodiment shown in FIGS. 1-2, the first scintillation crystal 101 and the second scintillation crystal 102 are both quadrangular prisms. In the embodiment shown in FIGS. 4-5, the first scintillation crystal 101 and the second scintillation crystal 102 are both triangular prisms. In the embodiment shown in FIG. 9, the first scintillation crystal 101 and the second scintillation crystal 102 are both hexagonal prisms. In other embodiments not shown, one of the first scintillation crystal 101 and the second scintillation crystal 102 can be a triangular prism and the other can be a quadrangular prism, so that two triangular prisms are sandwiched between every two quadrangular prisms and the two triangular prisms can be assembled into a quadrangular prism, thereby allowing the first scintillation crystal 101 and the second scintillation crystal 102 to be closely arranged.
返回参见图2，多个第一闪烁晶体101和多个第二闪烁晶体102在横向平面(例如XY平面)内密贴排列。横向平面垂直于晶体阵列100、阵列反光层200和光传感器层300的堆叠方向，堆叠方向为图1中所示的纵向方向Z-Z。多个第一闪烁晶体101可以分散在多个第二闪烁晶体102中，如图1所示，在相邻的第一闪烁晶体101之间可以设置有第二闪烁晶体102，相邻的第二闪烁晶体102之间可以设置有第一闪烁晶体101。但是并不意味着，任意相邻的第一闪烁晶体101之间均设置有第二闪烁晶体102，任意相邻的第二闪烁晶体102之间可以设置有第一闪烁晶体101。如图2所示，从Y方向上看，相邻的第一闪烁晶体101之间和相邻的第二闪烁晶 体102之间未设置有其他类型的闪烁晶体。而且，虽然图中沿着X方向，第一闪烁晶体101和第二闪烁晶体102交替排列，在未示出的其他实施例中，在相邻的第一闪烁晶体101之间可以设置有多个第二闪烁晶体102，相邻的第二闪烁晶体102之间可以设置有多个第一闪烁晶体101。也就是说，第一闪烁晶体101和第二闪烁晶体102可以以任意规则排列，也可以无规则地排列。Referring back to FIG. 2 , a plurality of first scintillation crystals 101 and a plurality of second scintillation crystals 102 are closely arranged in a transverse plane (e.g., an XY plane). The transverse plane is perpendicular to the stacking direction of the crystal array 100, the array reflective layer 200, and the light sensor layer 300, and the stacking direction is the longitudinal direction ZZ shown in FIG. 1 . A plurality of first scintillation crystals 101 may be dispersed in a plurality of second scintillation crystals 102. As shown in FIG. 1 , a second scintillation crystal 102 may be disposed between adjacent first scintillation crystals 101, and a first scintillation crystal 101 may be disposed between adjacent second scintillation crystals 102. However, this does not mean that a second scintillation crystal 102 is disposed between any adjacent first scintillation crystals 101, and a first scintillation crystal 101 may be disposed between any adjacent second scintillation crystals 102. As shown in FIG. 2 , viewed from the Y direction, the distance between adjacent first scintillation crystals 101 and the distance between adjacent second scintillation crystals 102 are substantially the same. In addition, although the first scintillation crystals 101 and the second scintillation crystals 102 are arranged alternately along the X direction in the figure, in other embodiments not shown, a plurality of second scintillation crystals 102 may be arranged between adjacent first scintillation crystals 101, and a plurality of first scintillation crystals 101 may be arranged between adjacent second scintillation crystals 102. In other words, the first scintillation crystals 101 and the second scintillation crystals 102 may be arranged in any regular pattern or may be arranged irregularly.
如图1所示，多个第一闪烁晶体101和多个第二闪烁晶体102中的每个的侧面都可以覆盖有朝向对应的闪烁晶体的内部反光的层内反光层(未示出)。沿垂直于横向平面的纵向方向Z-Z，晶体阵列可以具有相对的入射面(图1中的上表面)和出射面(图1中的下表面)。设置层内反光层可以防止闪烁晶体受到γ光子撞击时产生的闪烁光对相邻闪烁晶体造成影响。对单个闪烁晶体的闪烁光进行探测时，层内反光层可以提高探测的准确性。As shown in FIG1 , the side surface of each of the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 may be covered with an inner reflective layer (not shown) that reflects light toward the inside of the corresponding scintillation crystal. Along the longitudinal direction Z-Z perpendicular to the transverse plane, the crystal array may have a relative incident surface (upper surface in FIG1 ) and an exit surface (lower surface in FIG1 ). The provision of the inner reflective layer can prevent the scintillation light generated when the scintillation crystal is hit by a gamma photon from affecting the adjacent scintillation crystal. When detecting the scintillation light of a single scintillation crystal, the inner reflective layer can improve the accuracy of detection.
阵列反光层200可以覆盖在入射面上且朝向晶体阵列的内部反光。阵列反光层200可以防止闪烁晶体在受到γ光子撞击时产生的闪烁光从闪烁晶体的入射面射出。上文所说的层内反光层和阵列反光层200可以采用喷涂、镀膜(例如喷涂或镀银膜)或粘贴反光材料(例如ESR反光片)形成的。作为高效反光片，ESR(Enhanced Specular Reflector)在整个可见光光谱范围内的反射率都在98％以上，高于目前其他种类的反射片。ESR本身由高分子薄膜层组成，是更加绿色环保的反射片材料。ESR反光片的厚度在40微米左右，例如38微米。The array reflective layer 200 can cover the incident surface and reflect light toward the inside of the crystal array. The array reflective layer 200 can prevent the scintillation light generated by the scintillation crystal when it is hit by a gamma photon from emitting from the incident surface of the scintillation crystal. The inner layer reflective layer and the array reflective layer 200 mentioned above can be formed by spraying, coating (such as spraying or silver coating) or pasting reflective materials (such as ESR reflective sheet). As a high-efficiency reflective sheet, the reflectivity of ESR (Enhanced Specular Reflector) in the entire visible light spectrum is above 98%, which is higher than other types of reflective sheets currently available. ESR itself is composed of a polymer film layer and is a more environmentally friendly reflective sheet material. The thickness of the ESR reflective sheet is about 40 microns, for example 38 microns.
光传感器层300可以光耦合至出射面。光传感器层300可以包括一个或多个光传感器，光传感器可以为现有的或者未来可能出现的各种类型，例如光电倍增管(PMT)、硅光电倍增管(SiPM)等等。光耦合指的是闪烁光信号可以经过出射面在光传感器层与闪烁晶体之间传递。阵列反光层200可以和层内反光层配合，使闪烁晶体受到γ光子撞击而产生的闪烁光只能从出射层射出，进而使闪烁光只能经过出射层传递向光传感器层300。光传感器层300可以接收经过出射面传递出的闪烁光信号，进而可以将闪烁光信号转换为电信号，电信号可以用于后端的处理器进行数据处理，经过数据处理可以得到直观图像。The light sensor layer 300 can be optically coupled to the exit surface. The light sensor layer 300 can include one or more light sensors, and the light sensors can be various types that exist or may appear in the future, such as photomultiplier tubes (PMTs), silicon photomultipliers (SiPMs), etc. Optical coupling means that the scintillation light signal can be transmitted between the light sensor layer and the scintillation crystal through the exit surface. The array reflective layer 200 can cooperate with the reflective layer in the layer so that the scintillation light generated by the scintillation crystal being hit by γ photons can only be emitted from the exit layer, and then the scintillation light can only be transmitted to the light sensor layer 300 through the exit layer. The light sensor layer 300 can receive the scintillation light signal transmitted through the exit surface, and then convert the scintillation light signal into an electrical signal, which can be used for data processing by the back-end processor, and an intuitive image can be obtained after data processing.
对于分散在多个第二闪烁晶体102中的多个第一闪烁晶体101而言，当这些第一闪烁晶体101受到γ光子撞击时，如果这次撞击发生散射，散射产生的粒子和次级粒子可以在相邻的第二闪烁晶体102内沉积能量而被光传感器层300检测到，由此可以认定发生了ICS事件。第一闪烁晶体101 和第二闪烁晶体102在受到γ光子的撞击时，因具有不同的闪烁光衰减时间，根据光传感器层300采集到的光电信号可以确定ICS事件。For the plurality of first scintillation crystals 101 dispersed in the plurality of second scintillation crystals 102, when these first scintillation crystals 101 are hit by a gamma photon, if the hit is scattered, the particles and secondary particles generated by the scattering can deposit energy in the adjacent second scintillation crystals 102 and be detected by the optical sensor layer 300, thereby determining that an ICS event has occurred. When the first and second scintillation crystals 102 are struck by γ photons, they have different scintillation light decay times. Therefore, an ICS event can be determined according to the photoelectric signal collected by the photosensor layer 300 .
示例性地，可以基于QDC-TOT光电信息图确定ICS事件。在QDC-TOT光电信息图上不同类型的闪烁晶体内发生的能量沉积时间会位于光电信息图上的不同区域，如图11所示。QDC(Coulomb digitial convert)又被葡萄牙厂家称为charge integration，意为电荷数字转换，是电荷积分和。TOT(time over threshold)为过阈值时间，单位是皮秒(ps)。不同材料有着不同闪烁光衰减时间。例如，LYSO晶体和BGO晶体的闪烁光衰减时间分别为42ns和300ns。当第一闪烁晶体101和第二闪烁晶体102分别选用LYSO晶体和BGO晶体时，利用两种类型的闪烁晶体的闪烁光衰减时间的较大差异，光传感器层300检测到的事件可被初步识别为LYSO事件、BGO事件、或ICS事件。在QDC-TOT光电信息图上，LYSO事件集中在第一区域I内，BGO事件集中在第二区域II内，ICS事件集中在第三区域III内。由此，基于QDC-TOT光电信息图可以确定ICS事件。可以根据需要删除或矫正已确定的ICS事件，从而向重建算法提供更加精确的位置信息。Exemplarily, an ICS event can be determined based on a QDC-TOT optoelectronic information diagram. The energy deposition time occurring in different types of scintillation crystals on the QDC-TOT optoelectronic information diagram will be located in different areas on the optoelectronic information diagram, as shown in FIG11. QDC (Coulomb digitial convert) is also called charge integration by Portuguese manufacturers, which means charge digital conversion, and is the charge integral sum. TOT (time over threshold) is the threshold time, and the unit is picosecond (ps). Different materials have different scintillation light decay times. For example, the scintillation light decay times of LYSO crystal and BGO crystal are 42ns and 300ns, respectively. When the first scintillation crystal 101 and the second scintillation crystal 102 are selected from LYSO crystal and BGO crystal, respectively, the event detected by the optical sensor layer 300 can be preliminarily identified as a LYSO event, a BGO event, or an ICS event by utilizing the large difference in the scintillation light decay time of the two types of scintillation crystals. On the QDC-TOT optoelectronic information diagram, LYSO events are concentrated in the first area I, BGO events are concentrated in the second area II, and ICS events are concentrated in the third area III. Thus, ICS events can be determined based on the QDC-TOT optoelectronic information map. Determined ICS events can be deleted or corrected as needed, thereby providing more accurate position information to the reconstruction algorithm.
需要说明的是，基于QDC-TOT光电信息图来确定ICS事件，仅作为本发明提供的晶体阵列探测器10识别ICS事件的方法的示例，本领域的技术人员还可以采用现有的或者未来可能出现的各种方法基于光传感器层300采集到的光电信号来确定ICS事件。因此，确定ICS事件并不限于通过QDC-TOT光电信息图来实现。例如还可以采用延迟脉冲电荷积分法(Delayed charge integration,DCI)基于光传感器层300采集到的光电信号来确定ICS事件。It should be noted that determining an ICS event based on a QDC-TOT photoelectric information graph is only an example of a method for the crystal array detector 10 provided by the present invention to identify an ICS event. Those skilled in the art may also use various existing or future methods to determine an ICS event based on the photoelectric signal collected by the optical sensor layer 300. Therefore, determining an ICS event is not limited to being achieved through a QDC-TOT photoelectric information graph. For example, a delayed charge integration (DCI) method may also be used to determine an ICS event based on the photoelectric signal collected by the optical sensor layer 300.
由此可见，在本发明提供的晶体阵列探测器10中，由于在多个第一闪烁晶体101中分散有不同类型的多个第二闪烁晶体102，通过使第一闪烁晶体101和第二闪烁晶体102具有不同的闪烁光衰减时间，可以在光传感器层300中检测到的能量沉积事件中筛选出在两种类型的闪烁晶体内都发生过能量沉积的ICS事件。因此，通过有效地检测这些ICS事件，剩余散射事件占总事件数的比例大幅下降，这会极大提升重建图像的信噪比。晶体阵列中闪烁晶体的横截面越小，所识别的ICS事件占总事件的份额越大，本发明提供的晶体阵列探测器10对ICS事件的识别能力对于采用小尺寸闪烁晶体的晶体阵列来说，数据准确度的提升更大。此外，晶体阵列探测器10可以采用常规探测器结构设计，整体装置的造价为普通水平，因此也更 加实用。It can be seen that in the crystal array detector 10 provided by the present invention, since a plurality of second scintillation crystals 102 of different types are dispersed in a plurality of first scintillation crystals 101, by making the first scintillation crystals 101 and the second scintillation crystals 102 have different scintillation light decay times, ICS events in which energy deposition has occurred in both types of scintillation crystals can be screened out from the energy deposition events detected in the light sensor layer 300. Therefore, by effectively detecting these ICS events, the proportion of the remaining scattered events in the total number of events is greatly reduced, which greatly improves the signal-to-noise ratio of the reconstructed image. The smaller the cross-section of the scintillation crystals in the crystal array, the greater the proportion of the identified ICS events in the total events. The recognition capability of the crystal array detector 10 provided by the present invention for ICS events has a greater improvement in data accuracy for a crystal array using small-sized scintillation crystals. In addition, the crystal array detector 10 can adopt a conventional detector structure design, and the cost of the overall device is at an ordinary level, so it is also more More practical.
需要说明的是，晶体阵列100与光传感器层300可以通过光学胶水直接耦合，也可以在两者之间设置光导层。光导层可以由光导材料构成，光导材料包括但不限于树脂光导、透光玻璃、液体光导或其他多种材料。It should be noted that the crystal array 100 and the optical sensor layer 300 can be directly coupled by optical glue, or a light guide layer can be arranged between the two. The light guide layer can be made of light guide materials, including but not limited to resin light guides, transparent glass, liquid light guides or other materials.
示例性地，如图1-2所示，沿着横向平面内的第一横向方向X-X，多个第一闪烁晶体101和多个第二闪烁晶体102中的至少一部分可以交替排列。这样的布置，使得晶体阵列探测器10在第一横向方向X-X上对于探测ICS事件可以具有更高的灵敏度，从而可以具有更好地识别ICS事件的能力。如图2所示的是多个第一闪烁晶体101和多个第二闪烁晶体102在第一横向方向X-X上全都交替排列的一个示例性实施例，具有这样布置的晶体阵列探测器10，识别ICS事件的能力更强，整体装置的灵敏度和空间分辨率更高。Exemplarily, as shown in FIGS. 1-2 , along the first transverse direction X-X in the transverse plane, at least a portion of the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 may be arranged alternately. Such an arrangement enables the crystal array detector 10 to have a higher sensitivity for detecting ICS events in the first transverse direction X-X, thereby having a better ability to identify ICS events. As shown in FIG. 2 , an exemplary embodiment in which the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately in the first transverse direction X-X. The crystal array detector 10 having such an arrangement has a stronger ability to identify ICS events, and the sensitivity and spatial resolution of the overall device are higher.
示例性地，如图3所示，沿着横向平面内的第二横向方向Y-Y，多个第一闪烁晶体101和多个第二闪烁晶体102中的至少一部分可以交替排列，其中第二方向与第一方向之间具有夹角。这样的布置，使得晶体阵列探测器10在第二横向方向Y-Y上也可以具有更好的识别ICS事件的能力。如图3所示的是多个第一闪烁晶体101和多个第二闪烁晶体102在第二横向方向Y-Y上全部都交替排列的一个示例性实施例。具有这样布置的晶体阵列探测器10，识别ICS事件的灵敏度和分辨率都更好。Exemplarily, as shown in FIG3 , along the second transverse direction Y-Y in the transverse plane, at least a portion of the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 may be arranged alternately, wherein the second direction has an angle with the first direction. Such an arrangement enables the crystal array detector 10 to have a better ability to identify ICS events in the second transverse direction Y-Y. FIG3 shows an exemplary embodiment in which the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately in the second transverse direction Y-Y. The crystal array detector 10 with such an arrangement has better sensitivity and resolution in identifying ICS events.
较佳地，沿着第一横向方向X-X和第二横向方向Y-Y，多个第一闪烁晶体101和多个第二闪烁晶体102全部都交替排列。具有这样布置的晶体阵列探测器10，识别ICS事件的灵敏度和分辨率最佳。Preferably, along the first lateral direction X-X and the second lateral direction Y-Y, the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 are all arranged alternately. With the crystal array detector 10 arranged in this way, the sensitivity and resolution of identifying ICS events are optimal.
示例性地，第一横向方向X-X与第二横向方向Y-Y的夹角可以为90度。如图3所示的是第一横向方向X-X与第二横向方向Y-Y的夹角为90度，而且多个第一闪烁晶体101和多个第二闪烁晶体102在第一横向方向X-X和第二横向方向Y-Y上全部都交替排列的一个示例性实施例。这时，第一闪烁晶体101和第二闪烁晶体102交错排列，每个第一闪烁晶体101都被第二闪烁晶体102包围，同样，每个第二闪烁晶体102都被第一闪烁晶体101包围。这样，以γ光子撞击到第一闪烁晶体101上为例，散射产生的次级粒子很大概率将进入到与该第一闪烁晶体101相邻的第二闪烁晶体102(如图3中的箭头A所示)，进而在该第一闪烁晶体101和相邻的第二闪烁晶体102内都沉积能量，基于第一闪烁晶体101和第二闪烁晶体102的闪烁光衰减时间不同，因此能够基于光传感器层300采集的光电信号确 定这类ICS事件。也就是说，这类ICS事件是可以被识别出来的。当然，散射产生的次级粒子也有可能进入到与该第一闪烁晶体101对角线相邻的另一个第一闪烁晶体101中，如图3中的箭头B所示，进而在沿对角线相邻的两个第一闪烁晶体101中都沉积能量，由于该类ICS事件发生在同种闪烁晶体之间，因此无法通过QDC-TOT光电信息图被识别出来。但是这类ICS事件相比于箭头A所示的ICS事件发生的概率要少很多，因此较理想地，在每个闪烁晶体周围，无论是垂直于闪烁晶体的边的方向还是对角线方向都期望与不同类型的闪烁晶体相邻，后文还将针对该思路提供一种示例性的实施方式。但是可以理解的是，对于每个闪烁晶体，其周围相邻的同类型闪烁晶体越少，对于ICS事件的识别能力越强。具有图3所示的晶体阵列100的晶体阵列探测器10，已经能够在探测过程中识别出更大部分的ICS事件。因此，采用该实施例提供的晶体阵列探测器10成像时，可以极大地提升重建图像的信噪比，进而提高成像系统的灵敏度和空间分辨率。Exemplarily, the angle between the first lateral direction XX and the second lateral direction YY may be 90 degrees. As shown in FIG. 3 , an exemplary embodiment is shown in which the angle between the first lateral direction XX and the second lateral direction YY is 90 degrees, and a plurality of first scintillation crystals 101 and a plurality of second scintillation crystals 102 are all arranged alternately in the first lateral direction XX and the second lateral direction YY. At this time, the first scintillation crystals 101 and the second scintillation crystals 102 are arranged alternately, and each first scintillation crystal 101 is surrounded by the second scintillation crystal 102, and similarly, each second scintillation crystal 102 is surrounded by the first scintillation crystal 101. In this way, taking the collision of a gamma photon with the first scintillation crystal 101 as an example, the secondary particles generated by scattering will most likely enter the second scintillation crystal 102 adjacent to the first scintillation crystal 101 (as shown by arrow A in FIG. 3 ), and then deposit energy in both the first scintillation crystal 101 and the adjacent second scintillation crystal 102. Based on the different decay times of the scintillation light of the first scintillation crystal 101 and the second scintillation crystal 102, it is possible to determine the photoelectric signal collected by the optical sensor layer 300. This type of ICS event is determined. In other words, this type of ICS event can be identified. Of course, the secondary particles generated by scattering may also enter another first scintillation crystal 101 adjacent to the diagonal of the first scintillation crystal 101, as shown by arrow B in FIG3, and then deposit energy in the two first scintillation crystals 101 adjacent along the diagonal. Since this type of ICS event occurs between the same type of scintillation crystals, it cannot be identified by the QDC-TOT photoelectric information diagram. However, the probability of this type of ICS event is much less than that of the ICS event shown by arrow A. Therefore, ideally, around each scintillation crystal, whether it is perpendicular to the direction of the edge of the scintillation crystal or the diagonal direction, it is expected to be adjacent to different types of scintillation crystals. An exemplary implementation method for this idea will be provided later. However, it can be understood that for each scintillation crystal, the fewer the same type of scintillation crystals adjacent to it, the stronger the recognition ability for ICS events. The crystal array detector 10 with the crystal array 100 shown in FIG3 can already identify a larger part of ICS events during the detection process. Therefore, when the crystal array detector 10 provided in this embodiment is used for imaging, the signal-to-noise ratio of the reconstructed image can be greatly improved, thereby improving the sensitivity and spatial resolution of the imaging system.
图4示出了根据本申请的又一实施例。在该实施例中，第一闪烁晶体101和第二闪烁晶体102的横截面都呈等腰直角三角形。且针对每个等腰直角三角形的一个边，都与不同类型的闪烁晶体相邻，只有顶角的位置处与同种类型的闪烁晶体相邻。在此情况下，第一横向方向X-X与第二横向方向Y-Y的夹角非90度。在该实施例中，第一横向方向X-X与第二横向方向Y-Y的夹角为45度。当然，在纸面内且垂直于第一横向方向X-X的方向上，第一闪烁晶体101和第二闪烁晶体102也是交替排列的。也就是说，在该实施例中，第一闪烁晶体101和第二闪烁晶体102能够沿更多个方向交替排列。在采用该晶体阵列100的晶体阵列探测器10中，也能够识别出较大部分的ICS事件。图5示出了第一闪烁晶体101和第二闪烁晶体102的横截面都呈等腰直角三角形的另一种实施例。在该实施例中，可以认为第一闪烁晶体101和第二闪烁晶体102沿着相互垂直的第一横向方向X-X与第二横向方向Y-Y交替排列。FIG4 shows another embodiment according to the present application. In this embodiment, the cross-sections of the first scintillation crystal 101 and the second scintillation crystal 102 are both isosceles right triangles. And for each side of the isosceles right triangle, it is adjacent to a different type of scintillation crystal, and only the vertex is adjacent to the same type of scintillation crystal. In this case, the angle between the first transverse direction X-X and the second transverse direction Y-Y is not 90 degrees. In this embodiment, the angle between the first transverse direction X-X and the second transverse direction Y-Y is 45 degrees. Of course, in the direction within the paper and perpendicular to the first transverse direction X-X, the first scintillation crystal 101 and the second scintillation crystal 102 are also arranged alternately. That is to say, in this embodiment, the first scintillation crystal 101 and the second scintillation crystal 102 can be arranged alternately in more directions. In the crystal array detector 10 using the crystal array 100, a larger portion of ICS events can also be identified. FIG5 shows another embodiment in which the cross-sections of the first scintillation crystal 101 and the second scintillation crystal 102 are both isosceles right triangles. In this embodiment, it can be considered that the first scintillation crystals 101 and the second scintillation crystals 102 are alternately arranged along a first lateral direction X-X and a second lateral direction Y-Y that are perpendicular to each other.
需要说明的是，图4仅示出了第一横向方向X-X与第二横向方向Y-Y的夹角非90度的一个实施例，通过改变第一闪烁晶体101和第二闪烁晶体102的形状或者允许在第一闪烁晶体101和第二闪烁晶体102之间出现间隙，第一横向方向X-X与第二横向方向Y-Y的夹角还可以能有其他值。It should be noted that FIG4 only shows an embodiment in which the angle between the first lateral direction X-X and the second lateral direction Y-Y is not 90 degrees. By changing the shapes of the first scintillation crystal 101 and the second scintillation crystal 102 or allowing a gap to appear between the first scintillation crystal 101 and the second scintillation crystal 102, the angle between the first lateral direction X-X and the second lateral direction Y-Y may also have other values.
示例性地，晶体阵列100可以包括多个复合晶体层。如图6所示，该晶体阵列100包括两层复合晶体层，每层复合晶体层中都包括交替排列的 第一闪烁晶体101和第二闪烁晶体102。第一闪烁晶体101和第二闪烁晶体102在这两层复合晶体层中的排布方式是相同的。当然，在未示出的其他实施例中，两层复合晶体层中的闪烁晶体的排布方式也可以不同。在图6所示的实施例中，相邻的复合晶体层中的第一闪烁晶体101是错开的，且相邻的复合晶体层中的第二闪烁晶体102也是错开的。具有这样布置的晶体阵列探测器10可以降低γ光子在闪烁晶体内作用深度对空间分辨率的影响，提高了晶体阵列探测器10的空间分辨率。闪烁晶体不仅可以在复合晶体层内交错排列，在复合晶体层之间也可以交错排列，这样晶体阵列探测器10识别ICS事件的能力更强，特别地，这样晶体阵列探测器10还可以识别层间晶体间散射事件，CLCS事件是ICS事件的一种。因此提高了整体装置的灵敏度和空间分辨率。但是在未示出的其他实施例中，相邻的复合晶体层中可以仅一种类型的闪烁晶体是错开设置的。在此情况下，其他类型(例如第二类型和第三类型)的闪烁晶体在相邻的复合晶体层之间可以是不完全错开的。Exemplarily, the crystal array 100 may include a plurality of composite crystal layers. As shown in FIG6 , the crystal array 100 includes two composite crystal layers, each of which includes alternately arranged The first scintillation crystal 101 and the second scintillation crystal 102. The arrangement of the first scintillation crystal 101 and the second scintillation crystal 102 in the two composite crystal layers is the same. Of course, in other embodiments not shown, the arrangement of the scintillation crystals in the two composite crystal layers may also be different. In the embodiment shown in FIG6 , the first scintillation crystals 101 in adjacent composite crystal layers are staggered, and the second scintillation crystals 102 in adjacent composite crystal layers are also staggered. The crystal array detector 10 with such an arrangement can reduce the influence of the depth of action of γ photons in the scintillation crystals on the spatial resolution, and improve the spatial resolution of the crystal array detector 10. The scintillation crystals can be staggered not only in the composite crystal layer, but also between the composite crystal layers, so that the crystal array detector 10 has a stronger ability to identify ICS events. In particular, the crystal array detector 10 can also identify inter-layer crystal scattering events, and CLCS events are a type of ICS events. Therefore, the sensitivity and spatial resolution of the overall device are improved. However, in other embodiments not shown, only one type of scintillation crystals can be staggered in adjacent composite crystal layers. In this case, other types (eg, the second type and the third type) of scintillator crystals may not be completely staggered between adjacent composite crystal layers.
如图7所示，示例性地，除了上文提到的具有两种类型的闪烁晶体的复合晶体层之外，晶体阵列100中还可以包括单一晶体层。具体地，在该晶体阵列100中的上层为复合晶体层，下层为单一晶体层，单一晶体层可以仅包括一种类型的闪烁晶体104。闪烁晶体104可以是晶体阵列，也可以是连续晶体，该连续晶体指的是一整块闪烁晶体。闪烁晶体104可以与第一闪烁晶体101的类型相同，或者与第二闪烁晶体102的类型相同，或者与第一闪烁晶体101和第二闪烁晶体102的类型都不同。在这种晶体阵列中，发生在上层的一部分ICS事件能够别识别出来，但是下层的ICS事件可能无法被识别，但是无论如何，仍然能够提升重建图像的信噪比。需要说明的是，在其他未示出的实施例中，本发明提供的晶体阵列探测器可以包括两层或两层以上的晶体阵列，只要其中的至少一层是复合晶体层就都涵盖在本申请的保护范围之内。而且，复合晶体层在整个探测器中的位置也可以不做限定，例如可以位于靠近光传感器层300的最下层、和/或远离光传感器层300的最上层、和/或它们之间的中间层。As shown in FIG. 7 , illustratively, in addition to the composite crystal layer having two types of scintillation crystals mentioned above, the crystal array 100 may also include a single crystal layer. Specifically, the upper layer in the crystal array 100 is a composite crystal layer, and the lower layer is a single crystal layer, and the single crystal layer may include only one type of scintillation crystal 104. The scintillation crystal 104 may be a crystal array or a continuous crystal, and the continuous crystal refers to a whole piece of scintillation crystal. The scintillation crystal 104 may be of the same type as the first scintillation crystal 101, or of the same type as the second scintillation crystal 102, or of different types from both the first scintillation crystal 101 and the second scintillation crystal 102. In such a crystal array, a part of the ICS events occurring in the upper layer can be identified, but the ICS events in the lower layer may not be identified, but in any case, the signal-to-noise ratio of the reconstructed image can still be improved. It should be noted that in other embodiments not shown, the crystal array detector provided by the present invention may include two or more layers of crystal arrays, and as long as at least one layer thereof is a composite crystal layer, it is covered within the protection scope of the present application. Moreover, the position of the composite crystal layer in the entire detector may not be limited, for example, it may be located at the bottom layer close to the light sensor layer 300, and/or the top layer away from the light sensor layer 300, and/or the middle layer therebetween.
示例性地，如图8所示，复合晶体层中还可以包括第三类型的多个第三闪烁晶体103，多个第三闪烁晶体103可以分散在多个第一闪烁晶体101和多个第二闪烁晶体102中且可以与相邻的闪烁晶体密贴。第三闪烁晶体103可以具有不同于第一闪烁光衰减时间和第二闪烁光衰减时间的第三闪烁光衰减时间。第一闪烁光衰减时间、第二闪烁光衰减时间和第三闪烁光 衰减时间之间彼此的差距越大越好。第三闪烁晶体103可以采用与第一闪烁晶体101、第二闪烁晶体102不同的闪烁晶体材料制成。光传感器层300在一次γ光子射向晶体阵列探测器的事件中在两种不同类型的闪烁晶体中发生能量沉积的事件可能有三种情况，这三种情况分别对应于在第一闪烁晶体101和第二闪烁晶体102之间发生的ICS事件、在第一闪烁晶体101和第三闪烁晶体103之间的ICS事件、在第二闪烁晶体102和第三闪烁晶体103之间的ICS事件。当然，也可能在第一闪烁晶体101、第二闪烁晶体102和第三闪烁晶体103之间发生ICS事件。对于每个闪烁晶体而言，其周围的，尤其是对角线相邻的同种闪烁晶体的数量更少了，在图中的排布方式下，每个闪烁晶体仅具有两个对角相邻的同种闪烁晶体。因此，可以识别出更大量的ICS事件，因此具有这种晶体阵列100的晶体阵列探测器10识别ICS事件的能力也会更强。需要说明的是，上述附图展示了作为本申请的参考的实施例，但并不意味着本申请只能以这样的形式实现，在其他未示出的实施例中，本申请还可以具有各种其他相似的形式，在此不作赘述。For example, as shown in FIG8 , the composite crystal layer may further include a plurality of third scintillation crystals 103 of a third type, and the plurality of third scintillation crystals 103 may be dispersed in the plurality of first scintillation crystals 101 and the plurality of second scintillation crystals 102 and may be closely attached to adjacent scintillation crystals. The third scintillation crystals 103 may have a third scintillation light decay time that is different from the first scintillation light decay time and the second scintillation light decay time. The first scintillation light decay time, the second scintillation light decay time and the third scintillation light decay time may be different from each other. The greater the difference between the decay times, the better. The third scintillation crystal 103 can be made of a scintillation crystal material different from that of the first scintillation crystal 101 and the second scintillation crystal 102. There may be three situations in which the light sensor layer 300 has energy deposition in two different types of scintillation crystals in an event in which a γ photon is emitted to the crystal array detector. These three situations correspond to an ICS event between the first scintillation crystal 101 and the second scintillation crystal 102, an ICS event between the first scintillation crystal 101 and the third scintillation crystal 103, and an ICS event between the second scintillation crystal 102 and the third scintillation crystal 103. Of course, an ICS event may also occur between the first scintillation crystal 101, the second scintillation crystal 102, and the third scintillation crystal 103. For each scintillation crystal, the number of the same type of scintillation crystals around it, especially the diagonally adjacent scintillation crystals, is smaller. Under the arrangement in the figure, each scintillation crystal has only two diagonally adjacent scintillation crystals of the same type. Therefore, a larger number of ICS events can be identified, so the crystal array detector 10 with such a crystal array 100 will have a stronger ability to identify ICS events. It should be noted that the above-mentioned drawings show embodiments used as references for the present application, but this does not mean that the present application can only be implemented in this form. In other embodiments not shown, the present application may also have various other similar forms, which will not be described in detail here.
图9示出了根据本申请的另一种实施例的晶体阵列的排布方式。在该晶体阵列100中，包括不同类型的第一闪烁晶体101、第二闪烁晶体102和第三闪烁晶体103，第一闪烁晶体101、第二闪烁晶体102和第三闪烁晶体103的横截面都呈正六边形。并且，每个正六边形的边和顶角都可以邻接不同类型的闪烁晶体。具有这种布置的晶体阵列探测器10，每个闪烁晶体都被不同类型的闪烁晶体所包围。为方便描述，以一次γ光子射向晶体阵列探测器的事件中，γ光子首次撞击在第一闪烁晶体101上为例，γ光子产生的次级粒子可能会进入周围的一个或多个闪烁晶体，由于周围的这个或者这些闪烁晶体的闪烁光衰减时间与第一闪烁晶体101的闪烁光衰减时间不同，进而这些ICS事件都可以被识别出来。这样设计的晶体阵列探测器10识别的ICS事件更加完整全面，减少了探测中对于ICS事件的疏漏，进而减少了识别出ICS事件时的遗漏，因此提高了重建算法的信噪比，整体装置具有更好的灵敏度和空间分辨率。FIG9 shows the arrangement of a crystal array according to another embodiment of the present application. In the crystal array 100, different types of first scintillation crystals 101, second scintillation crystals 102 and third scintillation crystals 103 are included, and the cross-sections of the first scintillation crystals 101, the second scintillation crystals 102 and the third scintillation crystals 103 are all regular hexagons. Moreover, the sides and vertices of each regular hexagon can be adjacent to different types of scintillation crystals. In the crystal array detector 10 with such an arrangement, each scintillation crystal is surrounded by different types of scintillation crystals. For the convenience of description, in an event where a gamma photon is shot at the crystal array detector, the gamma photon first hits the first scintillation crystal 101 as an example, and the secondary particles generated by the gamma photon may enter one or more surrounding scintillation crystals. Since the scintillation light decay time of the surrounding one or more scintillation crystals is different from the scintillation light decay time of the first scintillation crystal 101, these ICS events can be identified. The crystal array detector 10 designed in this way identifies ICS events more completely and comprehensively, reduces omissions of ICS events in detection, and further reduces omissions when identifying ICS events, thereby improving the signal-to-noise ratio of the reconstruction algorithm, and the overall device has better sensitivity and spatial resolution.
需要说明的是，除了三角形、四边形和六边形之外，闪烁晶体还可以具有其他各种可能的形状，这适用于复合晶体层包括两种类型的闪烁晶体的情况，同时也适用于更多类型的闪烁晶体的情况。此外，不同类型的闪烁晶体可以具有相同的形状，也可以具有不同的情况。It should be noted that, in addition to triangles, quadrilaterals and hexagons, the scintillation crystals may have various other possible shapes, which is applicable to the case where the composite crystal layer includes two types of scintillation crystals, and also applicable to the case where there are more types of scintillation crystals. In addition, different types of scintillation crystals may have the same shape or different shapes.
图10示出了根据本申请的又一实施例。如图10所示，晶体阵列100 为多个且沿着纵向方向依次设置，每个晶体阵列都具有对应的阵列反光层200和光传感器层300。图10中示出的晶体阵列100为两个，在未示出的其他实施例中，晶体阵列100可以为更多个。相邻两个晶体阵列100中的一个所对应的光传感器层300与相邻两个晶体阵列100中的另一个所对应的阵列反光层200彼此相对设置。也就是说，上层的晶体阵列100所耦合的光传感器层300与下层的晶体阵列100上所覆盖的阵列反光层200彼此相对。在图示实施例中，上层的晶体阵列100所耦合的光传感器层300与下层的晶体阵列100上所覆盖的阵列反光层200彼此贴合，在未示出的其他实施例中，它们也可以是间隔开的。在此情况下，可以在间隔处放置上层光传感器的信号读出电路。如果将阵列反光层200、晶体阵列100和光传感器层300认为是一个重复单元的话，晶体阵列探测器10可以包括一个或多个这些的重复单元。具有这样布置的晶体阵列探测器10可以降低γ光子在闪烁晶体内作用深度对空间分辨率的影响，提高了晶体阵列探测器10的空间分辨率。需要说明的是，图10中所提到的晶体阵列100可以为上文中所提到的任意一种。FIG10 shows another embodiment according to the present application. As shown in FIG10 , a crystal array 100 There are multiple crystal arrays 100 and they are arranged in sequence along the longitudinal direction, and each crystal array has a corresponding array reflective layer 200 and a light sensor layer 300. There are two crystal arrays 100 shown in FIG. 10. In other embodiments not shown, there may be more crystal arrays 100. The light sensor layer 300 corresponding to one of the two adjacent crystal arrays 100 and the array reflective layer 200 corresponding to the other of the two adjacent crystal arrays 100 are arranged opposite to each other. That is to say, the light sensor layer 300 coupled to the upper crystal array 100 and the array reflective layer 200 covered on the lower crystal array 100 are opposite to each other. In the illustrated embodiment, the light sensor layer 300 coupled to the upper crystal array 100 and the array reflective layer 200 covered on the lower crystal array 100 are attached to each other. In other embodiments not shown, they may also be spaced apart. In this case, the signal readout circuit of the upper light sensor may be placed at the interval. If the array reflective layer 200, the crystal array 100 and the light sensor layer 300 are considered as a repeating unit, the crystal array detector 10 may include one or more of these repeating units. The crystal array detector 10 with such an arrangement can reduce the influence of the action depth of the gamma photons in the scintillation crystal on the spatial resolution, and improve the spatial resolution of the crystal array detector 10. It should be noted that the crystal array 100 mentioned in FIG. 10 may be any one of the ones mentioned above.
示例性地，相邻两个晶体阵列中的闪烁晶体可以具有相同的排布。相邻两个晶体阵列分别连接两个光传感器层300，两个光传感器层300分别单独检测两个晶体阵列中是否发生能量沉积，因此可以认为两个光传感器层300都从大量的能量沉积事件中识别出ICS事件。当然，相邻两个晶体阵列中的闪烁晶体也可以具有不相同的排布。在如图6所示的两个晶体阵列连接一个光传感器层300实施例中，相邻两个晶体阵列中的一个晶体阵列中的多个第一闪烁晶体与相邻两个晶体阵列中的另一个晶体阵列中的多个第一闪烁晶体错开。但是在图10所示的每个晶体阵列都连接光传感器层的实施例中，相邻两个晶体阵列中的一个晶体阵列中的多个第一闪烁晶体101与相邻两个晶体阵列中的另一个晶体阵列中的多个第一闪烁晶体101错开，也可以对准。类似地，这两个晶体阵列中的第二闪烁晶体102可以错开，也可以是对准的。Exemplarily, the scintillation crystals in two adjacent crystal arrays may have the same arrangement. Two adjacent crystal arrays are respectively connected to two optical sensor layers 300, and the two optical sensor layers 300 respectively detect whether energy deposition occurs in the two crystal arrays. Therefore, it can be considered that both optical sensor layers 300 identify ICS events from a large number of energy deposition events. Of course, the scintillation crystals in two adjacent crystal arrays may also have different arrangements. In the embodiment of two crystal arrays connected to one optical sensor layer 300 as shown in FIG6, a plurality of first scintillation crystals in one of the two adjacent crystal arrays are staggered with a plurality of first scintillation crystals in another of the two adjacent crystal arrays. However, in the embodiment of each crystal array connected to the optical sensor layer as shown in FIG10, a plurality of first scintillation crystals 101 in one of the two adjacent crystal arrays may be staggered with a plurality of first scintillation crystals 101 in another of the two adjacent crystal arrays, or may be aligned. Similarly, the second scintillation crystals 102 in the two crystal arrays may be staggered or aligned.
进一步地，本发明还提供一种发射成像设备。发射成像设备可以包括多个探测器，多个探测器可以合围形成检测腔体，检测腔体可以用于容纳待测对象。这些探测器中的至少一部分可以为如上文中所述的任一种晶体阵列探测器10。晶体阵列探测器10的晶体阵列100的入射面可以朝向检测腔体。这样，多个探测器的数据相组合，可以得到待测对象更全面完整的三维信息。在这些探测器中的一部分采用晶体阵列探测器10的情况下， 其他探测器可以为PET成像中常用的普通探测器。普通探测器和晶体阵列探测器10可以以任何合适的方式排布。Furthermore, the present invention also provides an emission imaging device. The emission imaging device may include a plurality of detectors, and the plurality of detectors may be combined to form a detection cavity, and the detection cavity may be used to accommodate an object to be detected. At least a portion of these detectors may be any of the crystal array detectors 10 described above. The incident surface of the crystal array 100 of the crystal array detector 10 may face the detection cavity. In this way, the data of the plurality of detectors may be combined to obtain more comprehensive and complete three-dimensional information of the object to be detected. In the case where a portion of these detectors adopts the crystal array detector 10, Other detectors may be common detectors commonly used in PET imaging. Common detectors and crystal array detectors 10 may be arranged in any suitable manner.
示例性地，检测腔体可以呈筒状。晶体阵列探测器10在检测腔体的外围排列成圆环。待测对象可以平躺进入到检测腔体内。筒状检测腔体结构也更加简单，易于实现。在未示出的其他实施例中，检测腔体也可以具有其他的形状，例如扁圆柱状、长方体状。Exemplarily, the detection cavity can be cylindrical. The crystal array detector 10 is arranged in a ring around the detection cavity. The object to be detected can lie flat and enter the detection cavity. The cylindrical detection cavity structure is also simpler and easy to implement. In other embodiments not shown, the detection cavity can also have other shapes, such as an oblate cylindrical shape or a rectangular parallelepiped shape.
示例性地，发射成像设备还可以包括处理器，处理器可以用于根据光传感器层300采集的光电信号确定混合能量沉积事件，混合能量沉积事件为在不同类型的闪烁晶体内都发生能量沉积的事件。通过上文的描述可知，混合能量沉积事件就是能够被识别的ICS事件。前文已经对确定ICS事件的方法进行了描述，这里不再赘述。Exemplarily, the emission imaging device may further include a processor, which may be used to determine a mixed energy deposition event based on the photoelectric signal collected by the light sensor layer 300, wherein the mixed energy deposition event is an event in which energy deposition occurs in different types of scintillation crystals. As can be seen from the above description, the mixed energy deposition event is an ICS event that can be identified. The method for determining an ICS event has been described above and will not be repeated here.
本发明已经通过上述实施例进行了说明，但应当理解的是，上述实施例只是用于举例和说明的目的，而非意在将本发明限制于所描述的实施例范围内。此外本领域技术人员可以理解的是，本发明并不局限于上述实施例，根据本发明的教导还可以做出更多种的变型和修改，这些变型和修改均落在本发明所要求保护的范围以内。本发明的保护范围由附属的权利要求书及其等效范围所界定。 The present invention has been described through the above embodiments, but it should be understood that the above embodiments are only for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, it can be understood by those skilled in the art that the present invention is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications all fall within the scope of the protection claimed by the present invention. The protection scope of the present invention is defined by the attached claims and their equivalents.

Claims (12)

  1. 一种晶体阵列探测器，其特征在于，包括：A crystal array detector, characterized by comprising:
    晶体阵列，所述晶体阵列包括复合晶体层，所述复合晶体层包括在横向平面内密贴排列的第一类型的多个第一闪烁晶体和第二类型的多个第二闪烁晶体，所述多个第一闪烁晶体分散在所述多个第二闪烁晶体中，所述多个第一闪烁晶体中的每个具有第一闪烁光衰减时间，所述多个第二闪烁晶体中的每个具有不同于所述第一闪烁光衰减时间的第二闪烁光衰减时间，所述多个第一闪烁晶体和所述多个第二闪烁晶体中的每个的侧面都覆盖有朝向对应的闪烁晶体的内部反光的层内反光层，沿垂直于所述横向平面的纵向方向，所述晶体阵列具有相对的入射面和出射面；A crystal array, the crystal array comprising a composite crystal layer, the composite crystal layer comprising a plurality of first scintillation crystals of a first type and a plurality of second scintillation crystals of a second type closely arranged in a transverse plane, the plurality of first scintillation crystals being dispersed in the plurality of second scintillation crystals, each of the plurality of first scintillation crystals having a first scintillation light decay time, each of the plurality of second scintillation crystals having a second scintillation light decay time different from the first scintillation light decay time, a side surface of each of the plurality of first scintillation crystals and the plurality of second scintillation crystals being covered with an inner reflective layer reflecting light toward the inside of the corresponding scintillation crystal, and the crystal array having an incident surface and an exit surface opposite to each other along a longitudinal direction perpendicular to the transverse plane;
    阵列反光层，所述阵列反光层覆盖在所述入射面上且朝向所述晶体阵列的内部反光；以及an array reflective layer, the array reflective layer covering the incident surface and reflecting light toward the interior of the crystal array; and
    光传感器层，所述光传感器层光耦合至所述出射面。A light sensor layer is optically coupled to the exit surface.
  2. 如权利要求1所述的晶体阵列探测器，其特征在于，沿着所述横向平面内的第一横向方向，所述多个第一闪烁晶体和所述多个第二闪烁晶体中的至少一部分交替排列。The crystal array detector according to claim 1, characterized in that along a first transverse direction in the transverse plane, at least a portion of the plurality of first scintillation crystals and the plurality of second scintillation crystals are alternately arranged.
  3. 如权利要求2所述的晶体阵列探测器，其特征在于，沿着所述第一横向方向，所述多个第一闪烁晶体和所述多个第二闪烁晶体完全交替排列。The crystal array detector according to claim 2, characterized in that, along the first transverse direction, the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged.
  4. 如权利要求2所述的晶体阵列探测器，其特征在于，沿着所述横向平面内的第二横向方向，所述多个第一闪烁晶体和所述多个第二闪烁晶体中的至少一部分交替排列，其中所述第二横向方向与所述第一横向方向之间具有夹角。The crystal array detector as described in claim 2 is characterized in that, along a second transverse direction in the transverse plane, at least a portion of the plurality of first scintillation crystals and the plurality of second scintillation crystals are arranged alternately, wherein the second transverse direction has an angle with the first transverse direction.
  5. 如权利要求4所述的晶体阵列探测器，其特征在于，所述夹角为90度。The crystal array detector according to claim 4, characterized in that the angle is 90 degrees.
  6. 如权利要求4所述的晶体阵列探测器，其特征在于，所述多个第一闪烁晶体和所述多个第二闪烁晶体沿着所述第一横向方向和所述第二横向方向均完全交替排列。The crystal array detector according to claim 4, characterized in that the plurality of first scintillation crystals and the plurality of second scintillation crystals are completely alternately arranged along the first lateral direction and the second lateral direction.
  7. 如权利要求1所述的晶体阵列探测器，其特征在于，所述晶体阵列包括多个所述复合晶体层，其中，相邻的复合晶体层中的第一闪烁晶体错开设置；和/或相邻的复合晶体层中的第二闪烁晶体错开设置。The crystal array detector as described in claim 1 is characterized in that the crystal array includes a plurality of the composite crystal layers, wherein the first scintillation crystals in adjacent composite crystal layers are staggered; and/or the second scintillation crystals in adjacent composite crystal layers are staggered.
  8. 如权利要求1所述的晶体阵列探测器，其特征在于，所述复合晶体层中还包括第三类型的多个第三闪烁晶体，所述多个第三闪烁晶体分散在 所述多个第一闪烁晶体和所述多个第二闪烁晶体中且与相邻的闪烁晶体密贴，所述多个第三闪烁晶体中的每个都具有不同于所述第一闪烁光衰减时间和所述第二闪烁光衰减时间的第三闪烁光衰减时间。The crystal array detector according to claim 1, characterized in that the composite crystal layer further comprises a plurality of third scintillation crystals of a third type, wherein the plurality of third scintillation crystals are dispersed in Among the plurality of first scintillation crystals and the plurality of second scintillation crystals and in close contact with adjacent scintillation crystals, each of the plurality of third scintillation crystals has a third scintillation light decay time different from the first scintillation light decay time and the second scintillation light decay time.
  9. 如权利要求8所述的晶体阵列探测器，其特征在于，在所述复合晶体层中，每种类型的闪烁晶体的顶角都邻接不同类型的闪烁晶体。The crystal array detector according to claim 8, characterized in that, in the composite crystal layer, the apex corners of each type of scintillation crystal are adjacent to scintillation crystals of different types.
  10. 如权利要求1-7中任一项所述的晶体阵列探测器，其特征在于，在所述复合晶体层中，每种类型的闪烁晶体的侧面都邻接不同类型的闪烁晶体。The crystal array detector according to any one of claims 1 to 7, characterized in that, in the composite crystal layer, the side surfaces of each type of scintillation crystal are adjacent to different types of scintillation crystals.
  11. 如权利要求1-9中任一项所述的晶体阵列探测器，其特征在于，所述晶体阵列为多个且沿着所述纵向方向依次设置，每个晶体阵列都具有对应的阵列反光层和光传感器层，The crystal array detector according to any one of claims 1 to 9, characterized in that the crystal arrays are multiple and are arranged in sequence along the longitudinal direction, and each crystal array has a corresponding array reflective layer and light sensor layer,
    相邻两个晶体阵列中的一个所对应的光传感器层与所述相邻两个晶体阵列中的另一个所对应的阵列反光层彼此相对设置。The light sensor layer corresponding to one of the two adjacent crystal arrays and the array reflective layer corresponding to the other of the two adjacent crystal arrays are arranged opposite to each other.
  12. 一种发射成像设备，其特征在于，包括：An emission imaging device, characterized in that it comprises:
    多个探测器，所述多个探测器合围形成检测腔体，所述检测腔体用于容纳待测对象，所述多个探测器中的至少一部分为如权利要求1-11中任一项所述的晶体阵列探测器，所述晶体阵列探测器的所述晶体阵列的入射面朝向所述检测腔体；以及A plurality of detectors, wherein the plurality of detectors together form a detection cavity, the detection cavity is used to accommodate an object to be detected, at least a portion of the plurality of detectors are crystal array detectors according to any one of claims 1 to 11, and an incident surface of the crystal array of the crystal array detector faces the detection cavity; and
    处理器，所述处理器用于根据所述光传感器层采集的光电信号确定混合能量沉积事件，其中，所述光电信号基于所述第一闪烁光衰减时间和所述第二闪烁光衰减时间生成，所述混合能量沉积事件为在不同类型的闪烁晶体内都发生能量沉积的事件。 A processor is used to determine a mixed energy deposition event based on a photoelectric signal collected by the photosensor layer, wherein the photoelectric signal is generated based on the first scintillation light decay time and the second scintillation light decay time, and the mixed energy deposition event is an event in which energy deposition occurs in different types of scintillation crystals.
PCT/CN2023/139612 2022-12-19 2023-12-18 Crystal array detector and emission imaging device WO2024131738A1 (en)

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