A precise positioning gamma photon detection unit and device

Abstract

The present disclosure provides a method for accurately positioning a gamma photon detection unit, a device, and a method for determining the position of a gamma photon, wherein the accurately positioning gamma photon detection unit includes: a scintillation crystal array and a plurality of photoelectric devices; the scintillation crystal array includes a side surface and two end surfaces at both ends of the side surface, the two end surfaces are respectively a photon incident surface and an exit surface, and the photoelectric devices are arranged on the side surface of the scintillation crystal array and surround the side surface. The present disclosure can not only accurately locate the incident position of the gamma photon in the detection unit, but also determine the incident direction of the gamma photon, while avoiding the loss of photon counts of the gamma photon in the incident direction, thereby improving the detection efficiency of the gamma photon.

Description

Technical Field

[0001] The present disclosure relates to the field of nuclear technology and its application technology, and in particular to a detection unit and device for accurately locating gamma photons. Background Art

[0002] In the gamma radiation imaging system, position-sensitive gamma radiation detectors are needed to achieve imaging. The detector is the main component of the imaging system, and its inherent spatial resolution, that is, the accuracy of the detector in measuring the incident position of the gamma photons incident on it, is a key factor affecting the gamma radiation imaging system.

[0003] There are two types of traditional position-sensitive radiation detectors. In clinically used gamma cameras and SPECT, large blocks of continuous NaI (Tl) scintillation crystals are often used to receive gamma rays, and multiple photomultiplier tubes arranged in a two-dimensional array are coupled to the distal surface in the direction of gamma ray incidence. When a gamma photon is incident on the NaI (Tl) scintillation crystal, the energy of the gamma photon is absorbed by the scintillation crystal and converted into a large number of scintillation photons emitted from the incident point. Scintillation photons can pass through the scintillation crystal material itself and be received by multiple photomultiplier tubes coupled to the distal surface. Photomultiplier tubes closer to the gamma photon incident point collect more scintillation photons and generate stronger electrical signals; photomultiplier tubes farther away collect fewer scintillation photons and generate weaker electrical signals. Therefore, the position of the incident point can be determined based on the combination of signal strengths of the photomultiplier tube array. The inherent spatial resolution of this detector is low. For example, the detectors of gamma cameras and SPECT generally have an inherent spatial resolution of 3 to 4 mm.

[0004] In PET, array-type scintillation crystals are mostly used, that is, the scintillation crystals are cut into multiple small strips. Generally, they are cut into 2-3 mm in human PET, so their inherent spatial resolution is higher than that of continuous crystal detectors. In order to determine which small crystal strip in the scintillation crystal array the gamma photon is incident on, one method is to completely wrap each small crystal strip with a reflective material (such as a total reflection film, a reflective coating material, etc.) that has the ability to fully reflect the scintillation photons, and couple each small crystal strip with an optoelectronic device (such as an avalanche photodiode, a silicon photomultiplier device) at the far end of the gamma photon incident surface, and determine which scintillation crystal strip has a gamma photon incident based on which optoelectronic device has a signal. This scheme can achieve the ideal inherent spatial resolution, that is, the same as the cutting size of the scintillation crystal strip. However, the one-to-one coupling scheme requires a large number of optoelectronic devices and back-end processing circuits. Another method is to couple a small number of optoelectronic devices to the far end of the gamma photon incident surface, and wrap the part of the scintillation crystal bar close to the gamma photon incident surface with reflective material, and bond the part away from the gamma photon incident surface with transparent material. In this way, a large number of scintillation photons generated by the gamma photon incident can be collected by multiple optoelectronic devices through other small crystal bars when they move to the area far away from the gamma photon incident surface. In this way, a method similar to that of a continuous crystal detector can be used to determine the position of the incident point based on the combination of signal strengths of the optoelectronic device array. The above schemes are widely used in human PET systems.

[0005] All of the above solutions require coupling optoelectronic devices on the far end surface in the direction of gamma photon incidence, and inevitably require the arrangement of electronic circuits behind the optoelectronic devices. Some gamma radiation imaging systems require the arrangement of two or more layers of detectors along the direction of gamma photon incidence. For example, a Compton camera requires the arrangement of a first layer of scattering layer detectors along the direction of gamma photon incidence, so that gamma photons undergo Compton scattering therein; and a second layer of absorption detectors is arranged thereafter to absorb photons that have undergone Compton scattering. Another example is a PET system in which multiple layers of detectors are arranged along the direction of gamma photon incidence, and the depth of action (DOI) is determined based on which layer the gamma photons are incident on, thereby reducing the impact of the parallax effect and improving the resolution of the imaging system. However, the optoelectronic devices coupled to the rear end of a layer of detectors will absorb gamma photons, reducing the detection efficiency of other detector layers after the detector layer. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] To solve the above problems, the main purpose of the present disclosure is to provide a device for accurately locating the incident position of gamma photons in a detection unit, and for determining the incident direction of gamma photons using a gamma photon detection unit, so as to solve at least one of the above problems.

[0008] (II) Technical solution

[0009] In order to achieve the above object, as one aspect of the present disclosure, a gamma photon detection unit is provided, which is used to determine the deposition position of incident gamma photons in the detection unit, comprising:

[0010] A scintillation crystal array, the scintillation crystal array comprising a side surface and two end surfaces at both ends of the side surface, the two end surfaces are respectively a photon incident surface and an exit surface;

[0011] A plurality of optoelectronic devices are disposed on the side surface of the scintillation crystal array and surround the side surface.

[0012] Furthermore, the scintillation crystal array is arranged in a cube or a cuboid as a whole, including two opposite end faces and the side faces between the two end faces, one of the two end faces is the incident face of the gamma photons, and the other is the exit face of the gamma photons.

[0013] Furthermore, the scintillation crystal array includes a plurality of scintillation crystal bars that are glued together or relatively fixed.

[0014] Furthermore, the scintillation crystal array includes at least two scintillation crystal bars made of different materials.

[0015] Furthermore, the difference between the refractive index of the bonding material between the scintillation crystal strips and the refractive index of the scintillation crystal material does not exceed 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through.

[0016] In the scintillation crystal array, for any scintillation crystal bar, there is at least one photoelectric device on the four sides of the scintillation crystal array, which can receive the scintillation photons emitted by the scintillation crystal bar and reach the photoelectric device through other scintillation crystal bars and the bonding materials between the scintillation crystal bars and output electrical signals.

[0017] After the scintillation photons are emitted by the corresponding scintillation crystal bars, the effective paths they pass through in any direction are different before they pass through a number of scintillation crystal bars and are received by a number of optoelectronic devices;

[0018] When the gamma photons are incident on different scintillation crystal bars, the plurality of optoelectronic devices output electrical signals with different amplitudes, and the electrical signals of the plurality of optoelectronic devices are used to calculate their weights to confirm the deposition position of the scintillation crystal bar received by the gamma photons;

[0019] Furthermore, the weighted positioning method is used to accurately determine the position information of the incident photon, including:

[0020] During the calibration process, a pencil-shaped gamma photon beam is used to scan each scintillation crystal unit one by one, and the signal E on all optoelectronic devices is calculated when the gamma photon enters each scintillation crystal. i, i is the photoelectric device number; then according to E i Calculate the weight position reference value x c，i and c，i , where w x，i and w y，i is a preset value; the calibrated {x c，i ,y c，i}Pre-save;

[0021] During the acquisition process, when a gamma photon is received, the weight position reference value x′ corresponding to the photon is calculated c and y′ c ; In {x c，i ,y c，i}Find the c and y′ c The closest x c，i and c，i , so that the corresponding scintillation crystal unit position is used as the incident position of the gamma photon.

[0022] As one aspect of the present disclosure, a device for detecting gamma photons is provided, comprising:

[0023] The detection device comprises a plurality of detection collimation unit layers which are arranged in multiple layers, or arranged in parallel, staggered or overlapped along the incident direction of the gamma rays emitted by the radiation source.

[0024] There is at least one scintillator crystal on the imaging detection units of several detection collimation unit layers, which can prevent gamma photons emitted from a point in the imaging field of view from passing through any optoelectronic devices or circuit board materials on the transmission path of the scintillator crystal that enters the last imaging detection unit layer.

[0025] (III) Beneficial effects

[0026] It can be seen from the above technical solutions that the gamma ray imaging detection unit and device disclosed in the present invention have at least one of the following beneficial effects:

[0027] (1) Compared with the existing detection unit and device that couples photoelectric devices on the far end surface of the incident direction of gamma photons, the present disclosure discloses a gamma photon detection unit and device, which utilizes the plurality of photoelectric devices to be arranged on the side of the scintillation crystal array and surround the four side surfaces. When gamma photons are incident from the side of the scintillation crystal array, the loss of photon counting can be avoided in the incident direction of the gamma photons, thereby improving the detection efficiency of gamma photons.

[0028] (2) The difference between the refractive index of the bonding material between the scintillation crystal strips and the refractive index of the scintillation crystal material in the present disclosure does not exceed 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through. The weighted positioning method is used to accurately determine the position information of the incident photon, accurately obtain the receiving position of the incident gamma photon, and improve the gamma photon position progress. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of the gamma photon detection unit of Example 1.

[0030] Figure 2 This is a schematic diagram of the structure of the gamma photon detection unit of Example 2.

[0031] Figure 3 This is a schematic diagram of the structure of the gamma photon detection unit of Example 3.

[0032] Figure 4 This is a schematic diagram of the structure of the gamma photon detection unit of Example 4.

[0033] Figure 5 This is a schematic diagram of the structure of the gamma photon detection unit of Example 5.

[0034] Figure 6 This is a schematic diagram of the structure of the gamma photon detection unit of Example 6.

[0035] Figure 7 This is a schematic diagram of the structure of the gamma photon detection unit of Example 7.

[0036] Figure 8 This is a schematic diagram of the structure of the gamma photon detection device of Example 8.

[0037] Fig. 9 This is a schematic diagram of the structure of the gamma photon detection device of Example 9.

[0038] Fig.10 This is a schematic diagram of the structure of the gamma photon detection device of Example 10. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0040] The present disclosure proposes a gamma-ray imaging detection unit for determining the deposition position of incident gamma photons in the detection unit, comprising: a scintillation crystal array, the scintillation crystal array comprising a side surface and two end surfaces at both ends of the side surface, the two end surfaces being a photon incident surface and an exit surface, respectively; and a plurality of photoelectric devices, the plurality of photoelectric devices being arranged on the side surface of the scintillation crystal array and surrounding four side surfaces.

[0041] Furthermore, the scintillation crystal array is arranged as a cube or a cuboid as a whole, including two opposite end faces and the side face between the two end faces, one of the two end faces is the incident face of the gamma photons, and the other is the exit face of the gamma photons. The scintillation crystal array includes a plurality of scintillation crystal bars that are glued or relatively fixed. The scintillation crystal array includes at least two scintillation crystal bars of different materials.

[0042] Furthermore, the difference between the refractive index of the bonding material between the scintillation crystal strips and the refractive index of the scintillation crystal material is no more than 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through. In the scintillation crystal array, for any scintillation crystal strip, there is at least one optoelectronic device on the four sides of the scintillation crystal array, which can receive the scintillation photons emitted by the scintillation crystal strip and pass through other scintillation crystal strips and the bonding material between the scintillation crystal strips to reach the optoelectronic device and output an electrical signal.

[0043] After the scintillation photons are emitted from the corresponding scintillation crystal bars, they pass through different effective paths in any direction before passing through a number of scintillation crystal bars and being received by a number of optoelectronic devices; wherein when the gamma photons are incident on different scintillation crystal bars, the amplitudes of the electrical signals output by the several optoelectronic devices are different, and the electrical signals of the several optoelectronic devices are used to calculate their weights to confirm the deposition position of the scintillation crystal bar where the gamma photons are received;

[0044] Furthermore, the weighted positioning method is used to accurately determine the position information of the incident photon, including:

[0045] During the calibration process, a pencil-shaped gamma photon beam is used to scan each scintillation crystal unit one by one, and the signal E on all optoelectronic devices is calculated when the gamma photon enters each scintillation crystal. i , i is the photoelectric device number; then according to E i Calculate the weight position reference value x c，i and c，i , where w x，i and w y，i is a preset value; the calibrated {x c，i ,y c，i}Pre-save;

[0046] During the acquisition process, when a gamma photon is received, the weight position reference value x′ corresponding to the photon is calculated c and y′ c ; In {x c，i ,y c，i}Find the c and y′ c The closest x c，i and c，i, so that the corresponding scintillation crystal unit position is used as the incident position of the gamma photon.

[0047] Compared with the existing detection unit and device that couples optoelectronic devices on the far end surface of the incident direction of gamma photons, the present disclosure discloses a precisely positioned gamma photon detection unit and device, which utilizes the plurality of optoelectronic devices to be arranged on the side of the scintillation crystal array and surround the four side surfaces. The gamma photons are incident from the scintillation crystal array including the side surface. When the photons pass through, they will not be blocked by optoelectronic devices and circuit boards, which reduces the impact of photons being absorbed by optoelectronic devices and circuit boards on image quality. The gamma rays pass through the front and back of a single detection collimation module. The optoelectronic devices and circuit boards are located on the side of the detector in the incident direction of the gamma photons, which will not block the gamma photons between the multi-layer detectors, thus avoiding the impact on image quality. The loss of photon counts in the incident direction of the gamma photons can be avoided, thereby improving the detection efficiency of gamma photons.

[0048] In the present disclosure, the difference between the refractive index of the bonding material between the scintillation crystal bars and the refractive index of the scintillation crystal material (the difference between the refractive index r1 of the bonding material between the scintillation crystal bars involved in the present disclosure and the refractive index r2 of the scintillation crystal material Δr=|r1-r2| / min(r1, r2), that is, the ratio of the absolute value of the difference between r1 and r2 to the smaller of r1 and r2) does not exceed 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through. The weighted positioning method is used to accurately determine the position information of the incident photons, accurately obtain the receiving position of the incident gamma photons, and improve the position progress of the gamma photons. And before the gamma photons enter the scintillation crystal bars of the scintillation crystal array of the imaging detection unit, at least one of the three factors, namely, the number of the previous scintillation crystal bars, the length of the scintillation crystal bars, and the material of the scintillation crystal bars, is different. That is to say, there is at least one such scintillation crystal bar in the scintillation crystal array of the plurality of imaging detection units arranged in a staggered and overlapping manner, so that photons from different directions in the object to be detected can pass through other scintillation crystal bars and the bonding materials between the scintillation crystal bars before entering the scintillation crystal bar, reach the scintillation photons of the photoelectric device and output electrical signals.

[0049] The scintillation crystal array of each imaging detection unit is arranged in a two-dimensional array, and the scintillation crystal array includes a plurality of independent scintillation crystal bars and / or a plurality of spliced ​​scintillation crystal bars. The scintillation crystal array can be composed of any one or more combinations of NaI, CsI, LaBr3, CLYC, BGO, LSO, LYSO, GSO, YSO, YAP, and GAGG, and can also be filled between the plurality of independent scintillation crystal bars with different contrast densities such as air, resin, polyethylene plastic, and low-density material. The two-dimensional array arrangement of the scintillation crystals can realize a more complex arrangement of scintillation crystal blocks of different crystal materials and different spacings, thereby improving the imaging performance of the present SPECT device.

[0050] As one aspect of the present disclosure, a device for detecting gamma photons is provided, comprising:

[0051] The detection device comprises a plurality of detection collimation unit layers which are arranged in multiple layers, or arranged in parallel, staggered or overlapped along the incident direction of the gamma rays emitted by the radiation source.

[0052] There is at least one scintillator crystal on the imaging detection units of several detection collimation unit layers, which can prevent gamma photons emitted from a point in the imaging field of view from passing through any optoelectronic devices or circuit board materials on the transmission path of the scintillator crystal that enters the last imaging detection unit layer.

[0053] Furthermore, the gamma photon detection unit and device disclosed in the present invention can be used in systems such as SPECT or PET, or for simultaneous acquisition of SPECT and PET.

[0054] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0055] Example 1

[0056] like Figure 1 As shown, the imaging detection unit 1 includes a scintillation crystal array 2 and an optoelectronic device 3. The scintillation crystal array 2 is a cube or a cuboid structure, including four side faces and two end faces. The optoelectronic device 3 is coupled to the side face of the scintillation crystal array 2.

[0057] The scintillation crystal array 2 is a two-dimensional array structure, including a plurality of scintillation crystal bars 4 and a plurality of scintillation crystal bars 5, wherein the plurality of scintillation crystal bars 4 and the plurality of scintillation crystal bars 5 are arranged alternately, and the materials of two adjacent scintillation crystals 4 and 5 are different. The difference between the refractive index of the bonding material between the scintillation crystal bars and the refractive index of the scintillation crystal material does not exceed 50%, and the bonding material allows the scintillation photons S emitted from the scintillation crystal to pass through.

[0058] In the scintillation crystal array, for any scintillation crystal bar, there is at least one photoelectric device on the four sides of the scintillation crystal array, which can receive the scintillation photons emitted by the scintillation crystal bar and reach the photoelectric device through other scintillation crystal bars and the bonding materials between the scintillation crystal bars and output electrical signals.

[0059] After being emitted by the corresponding scintillation crystal bar, the scintillation photons pass through different effective paths in any direction before passing through a number of scintillation crystal bars and being received by a number of optoelectronic devices.

[0060] Wherein, when the gamma photon P is incident on different scintillation crystal bars, the amplitudes of the electrical signals output by the plurality of photoelectric devices are different, and the weights thereof can be calculated by using the electrical signals of the plurality of photoelectric devices to confirm the deposition position of the scintillation crystal bar received by the gamma photon;

[0061] Example 2

[0062] like Figure 2 As shown, in this embodiment, the detection unit 1 includes a scintillation crystal array 2 and a plurality of photoelectric devices 3. The scintillation crystal array 2 is a two-dimensional array structure, including a plurality of scintillation crystal bars 4 and a plurality of scintillation crystal bars 5. The scintillation crystal array has four sides. A plurality of photoelectric devices are arranged on each side of the scintillation crystal. Each photoelectric device is coupled to a side of the scintillation crystal bar. The width of each photoelectric device is the same as the width of each scintillation crystal bar. The plurality of scintillation crystal bars 4 and the plurality of scintillation crystal bars 5 are arranged alternately, and the materials of two adjacent scintillation crystal bars 4 and 5 are different. The refractive index of the scintillation crystal is very small, allowing a large number of scintillation photons to pass through.

[0063] The difference between the refractive index of the bonding material between the scintillation crystal strips and the refractive index of the scintillation crystal material does not exceed 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through and be received by the photoelectric device to generate an electrical signal. When the gamma photon incident point P1 is at the center of the crystal array, the signal amplitudes on each photoelectric device are close; when the gamma photon incident point P2 is at the edge of the crystal array, the signals on each photoelectric device are significantly different, and the signal of the photoelectric device close to the incident point is very large. The output electrical signal amplitudes of several photoelectric devices are different. The electrical signals of the several photoelectric devices are used to calculate their weights to confirm the deposition position of the scintillation crystal strips received by the gamma photons. This embodiment uses the weight positioning method to accurately determine the incident photon position information. Therefore, the combination of the photoelectric device signals is related to the position of the gamma photon incident point. Different scintillation crystal materials will affect the calculation results of the gamma photon position.

[0064] Example 3

[0065] like Figure 3As shown, in this embodiment, the detection unit 1 includes a scintillation crystal array 2 and four photoelectric devices 3. The scintillation crystal array has four sides. The four photoelectric devices are respectively coupled to the four sides of the scintillation crystal array and surround the four sides. Each photoelectric device is coupled to one of the four sides of the scintillation crystal array and surrounds the one side. The scintillation crystal array 2 is a two-dimensional array structure, including a plurality of scintillation crystal bars 4 and a plurality of scintillation crystal bars 5. The plurality of scintillation crystal bars 4 and the plurality of scintillation crystal bars 5 are arranged alternately, and the materials of two adjacent scintillation crystal bars 4 and 5 are different. Different gamma photons have different incident positions, and the corresponding output electrical signal amplitudes and curves of the four sides are different. The weight positioning method is used to accurately determine the incident photon position information. Compared with the aforementioned implementation case, this embodiment can reduce the number of channels of the photoelectric device, reduce the design difficulty and processing requirements.

[0066] Example 4

[0067] like Figure 4 In this embodiment, the detection unit 1 includes a scintillation crystal array 2 and a plurality of photoelectric devices 3. The scintillation crystal array 2 is a two-dimensional array structure, including a plurality of scintillation crystal bars 4 and a plurality of scintillation crystal bars 5. The scintillation crystal array has four sides. A plurality of photoelectric devices are arranged on each side of the scintillation crystal. The width of each photoelectric device is greater than the width of each scintillation crystal bar. The plurality of scintillation crystal bars 4 and the plurality of scintillation crystal bars 5 are arranged alternately, and the materials of two adjacent scintillation crystal bars 4 and 5 are different. Preferably, the width of each photoelectric device is 1.5 times the width of each scintillation crystal bar. This reduces the accuracy of the incident point position measurement, but saves the photoelectric device and the subsequent electronic circuit, reducing the cost.

[0068] Example 5

[0069] like Figure 5In this embodiment, the detection unit 1 includes a scintillation crystal array 2 and a plurality of optoelectronic devices 3. The scintillation crystal array has four sides, and a plurality of optoelectronic devices are arranged on each of the sides of the scintillation crystal. The scintillation crystal array 2 is a two-dimensional array structure, including a plurality of first scintillation crystal groups G1 and a plurality of second scintillation crystal groups G2. Each first scintillation crystal group includes two scintillation crystal bars 4, and each second scintillation crystal group includes two scintillation crystal bars 5. The first crystal groups and the second crystal groups are arranged alternately, and the scintillation crystal bars 4 and the scintillation crystal bars 5 are made of different materials. The difference in refractive index between the material of the scintillation crystal bar 4 and the material of the scintillation crystal bar 5 is less than but close to 50%, so that the scintillation light has a certain proportion of transmission and a certain proportion of total reflection at the interface between the scintillation crystal bar 4 and the scintillation crystal bar 5. Therefore, in addition to the signal combination of the optoelectronic device being related to the incident position of the gamma photon similar to the first embodiment, the propagation ratio of the scintillation photons in the region along the same type of crystal bar is higher, and the corresponding optoelectronic device coupled to the type of crystal bar has a higher signal, thereby further enhancing the effect of judging the position of the incident photon.

[0070] Example 6

[0071] like Figure 6 In this embodiment, the refractive index of the material of the scintillation crystal bar 4 and the material of the scintillation crystal bar 5 are close, and the difference in the attenuation coefficient of the gamma photon is more than 20%. Therefore, the probability of the gamma photon incident on the material of the scintillation crystal bar 4 and the scintillation crystal bar 5 is significantly different. When judging the incident position of the gamma photon, the difference in the incidence probability can be further used to improve the judgment accuracy.

[0072] Example 7

[0073] like Figure 7 In this embodiment, on the interface between the scintillation crystal strip 4 and the scintillation crystal strip 5, a part of the area is covered with a total reflection reflective film 6, and another part of the area is bonded with a material transparent to the scintillation photons. This limits the propagation path of the scintillation photons, making the signal on the optoelectronic device more sensitive to the change of the incident position of the gamma photons.

[0074] Example 8

[0075] In this embodiment, if Figure 8 As shown, the radioactive nuclide in the detected object (such as human body) 10 generates gamma photons, and the gamma photon detection device includes imaging detection units 11 and 12. The imaging detection units 11 and 12 are arranged in two layers from inside to outside along the moving direction of the gamma photons outside the human body.

[0076] Among them, the imaging detection unit in front along the direction of movement of the gamma photons is the imaging detection unit 11, and the imaging detection unit in the rear along the direction of movement of the gamma photons is the imaging detection unit 12, and the imaging detection unit 11 is closer to the human body than the imaging detection unit 12. The imaging detection units 11 and 12 both include a scintillation crystal array 13 and photoelectric devices 14, 15, 16, and 17. The scintillation crystal array 3 is composed of crystal bars with a variety of different gamma photon attenuation coefficients and has an overall rectangular structure, including four side faces and two end faces. The photoelectric devices 14, 15, 16, and 17 are respectively coupled to the four side faces (for outputting digital signals of the position, energy, and time information of the incident gamma photons after the gamma photons are deposited), the end face of the two end faces close to the object to be detected is the gamma photon incident face, and the end face of the two end faces away from the object to be detected is the gamma photon exit face. Compared with the imaging detection unit 1, the structure of the imaging detection unit 2 is the same as that of the imaging detection unit 1, except that the scintillation crystal array can be composed of crystal bars with multiple different gamma photon attenuation coefficients or crystal bars with the same gamma photon attenuation coefficient.

[0077] The scintillation crystal array 13 is a two-dimensional array structure, including a plurality of scintillation crystal bars 21 and a plurality of scintillation crystal bars 22, the scintillation crystal bars 21 and the plurality of scintillation crystal bars 22 are arranged alternately, and the materials of two adjacent scintillation crystal bars 21 and 22 can be different or the same (the scintillation crystal bars in the same row of the two-dimensional array structure in this embodiment are of the same material, and the materials of adjacent scintillation crystal bars in the same column are different). Preferably, the scintillation crystal array includes a plurality of scintillation crystal bars of different materials and different spacings to improve the imaging performance of the system.

[0078] When a photon passes through the imaging detection unit 11 without being absorbed by the imaging detection unit 11, and is absorbed by the imaging detection unit 12 and deposits energy after reaching the imaging detection unit 12, the accurate action position information of the gamma photon in the imaging detection unit 12 can be obtained by processing the signal output by the photoelectric device through the weight position algorithm. In this embodiment, the imaging detection units 11 and 12 are arranged in multiple layers, and the action position of the gamma photon in the imaging detection unit 12 is connected with the position of different crystal bars in the imaging detection unit 11, which can correspond to the position of the gamma radiation source from different directions in the human body. And because the crystal array in the imaging detection unit 1 is composed of a variety of crystal bars with different gamma photon attenuation coefficients, the probability of gamma photons from different directions in the human body passing through the imaging detection unit 11 and not being absorbed is different. Therefore, according to the action position information of the gamma photon in the imaging detection unit 12 and the crystal attenuation coefficient distribution information in the imaging detection unit 11, the probability of the photons detected in the imaging detection unit 12 coming from different directions in the human body can also be obtained, that is, the effect of distinguishing the direction of the incident gamma photon is achieved.

[0079] Furthermore, when photons pass through, they will not be blocked by optoelectronic devices and circuit boards, thereby improving the detection efficiency of gamma photons, thereby avoiding the influence of photons absorbed by optoelectronic devices and circuit boards on image quality.

[0080] Example 9

[0081] In this embodiment, if Fig. 9 As shown, the radioactive nuclide in the detected object (e.g., human body) 10 generates gamma photons, and the gamma photon detection device includes imaging detection units 11, 12, and 18. The imaging detection units 11, 12, and 18 are arranged in three layers from the inside to the outside along the moving direction of the gamma photons outside the human body.

[0082] The imaging detection unit at the front side along the gamma photon motion direction is the imaging detection unit 11, the imaging detection unit at the rear side along the gamma photon motion direction is the imaging detection unit 18, and the imaging detection unit between the imaging detection unit 11 and the imaging detection unit 18 along the gamma photon motion direction is the imaging detection unit 12. The imaging detection unit 11 is closer to the human body than the imaging detection unit 12, and the imaging detection unit 18 is farther away from the human body than the imaging detection unit 12.

[0083] The imaging detection unit 11 has the same structure as the imaging detection unit 12, including a scintillation crystal array 13 and optoelectronic devices 14, 15, 16, and 17. The scintillation crystal array 13 is a rectangular parallelepiped structure as a whole, including four side faces and two end faces. The optoelectronic devices 14, 15, 16, and 17 are coupled to the four side faces, respectively, the end face of the two end faces close to the object to be detected is the gamma photon incident face, and the end face of the two end faces far from the object to be detected is the gamma photon exit face.

[0084] The imaging detection unit 18 has a different structure from the imaging detection units 11 and 12. The imaging detection unit 18 includes a scintillation crystal array 19 and a photoelectric device 20. The scintillation crystal array 19 is a rectangular parallelepiped structure as a whole, including four side faces and two end faces. The photoelectric device 20 is coupled to the end face of the scintillation crystal array 19 away from the detected object.

[0085] The scintillation crystal arrays 13 and 19 are two-dimensional array structures, each including a plurality of scintillation crystal bars 21 and a plurality of scintillation crystal bars 22 . The plurality of scintillation crystal bars 21 and the plurality of scintillation crystal bars 22 are arranged alternately, and two adjacent scintillation crystals 21 and 22 are made of different materials.

[0086] The structures of the scintillation crystal array 19 and the scintillation crystal array 13 may be the same or different. The materials and arrangement of the scintillation crystal bars of the scintillation crystal array 19 and the scintillation crystal array 13 may be the same or different.

[0087] When photons pass through the front and rear end faces of the imaging detection unit 11 (or the imaging detection units 12 and 18), the accurate action information of the gamma photons on the imaging detection unit 11 (or the imaging detection units 12 and 18) can be obtained by processing the signals output by the photoelectric device. In this embodiment, the imaging detection units 11, 12, and 18 are arranged in multiple layers, and the action direction of the gamma photons absorbed on the imaging detection unit 3 is determined by the action position on the imaging detection unit 3, the crystal attenuation coefficient distribution information on the imaging detection unit 2, and the crystal attenuation coefficient distribution information on the imaging detection unit 1. Therefore, a better directional resolution effect can be achieved than in Example 8. In combination with the change of the deposition probability of gamma photons on the scintillation crystal in the double-layer imaging detection unit in Example 8 with the incident direction of the gamma photons, the incident direction of the gamma photons is determined. Therefore, the three-layer structure can collect more photons than the two-layer structure and achieve a better effect of distinguishing the direction.

[0088] Example 10

[0089] In this embodiment, if Fig.10 As shown, the radioactive nuclide in the detected object (e.g., human body) 100 generates gamma photons, and the gamma photon detection device includes a plurality of imaging detection units 101, a plurality of imaging detection units 102, and a plurality of imaging detection units 108. The plurality of imaging detection units 101 constitute a detection collimation unit 113, the plurality of imaging detection units 102 constitute a detection collimation unit 114, and the plurality of imaging detection units 108 constitute a detection collimation unit 115. The detection collimation units 113, the detection collimation units 114, and the detection collimation units 115 are arranged in three layers from the inside to the outside along the moving direction of the gamma photons outside the human body.

[0090] The imaging detection unit at the front side along the gamma photon moving direction is the detection collimation unit 113, the detection collimation unit at the rear side along the gamma photon moving direction is the detection collimation unit 115, and the detection collimation unit between the detection collimation unit 113 and the detection collimation unit 115 along the gamma photon moving direction is the detection collimation unit 114. The detection collimation unit 113 is closer to the human body than the detection collimation unit 114, and the detection collimation unit 115 is farther away from the human body than the detection collimation unit 114.

[0091] The detection collimation unit 113 is in the shape of a ring and is disposed around the human body. The detection collimation unit 114 is in the shape of a ring and is disposed around the detection collimation unit 113. The detection collimation unit 115 is in the shape of a ring and is disposed around the detection collimation unit 114.

[0092] The multiple imaging detection units 101 included in the detection collimation unit 113 are arranged outside the human body along the circumference of the human body, so that the whole is in a circular ring shape. Similar to the multiple imaging detection units 101, the multiple imaging detection units 102 are arranged outside the human body along the circumference of the detection collimation unit 113, so that the whole is in a circular ring shape. The multiple imaging detection units 108 are arranged outside the human body along the circumference of the detection collimation unit 114, so that the whole is in a circular ring shape.

[0093] The imaging detection unit 101 has the same structure as the imaging detection unit 102, including a scintillation crystal array 103 and optoelectronic devices 104, 105, 106, and 107. The scintillation crystal array 103 is a rectangular parallelepiped structure as a whole, including four side faces and two end faces. The optoelectronic devices 104, 105, 106, and 107 are coupled to the four side faces, respectively, the end face of the two end faces close to the object to be detected is the gamma photon incident face, and the end face of the two end faces far from the object to be detected is the gamma photon exit face.

[0094] The imaging detection unit 108 has a different structure from the imaging detection units 101 and 102. The imaging detection unit 108 includes a scintillation crystal array 109 and a photoelectric device 110. The scintillation crystal array 109 is a rectangular parallelepiped structure, including four side faces and two end faces. The photoelectric device 110 is coupled to the end face of the scintillation crystal array 109 away from the detected object.

[0095] The scintillation crystal array 103 is a two-dimensional array structure, including a plurality of scintillation crystal bars 111 and a plurality of scintillation crystal bars 112 . The plurality of scintillation crystal bars 111 and the plurality of scintillation crystal bars 112 are arranged alternately, and two adjacent scintillation crystals 111 and 112 are made of different materials.

[0096] The structures of the scintillation crystal array 109 and the scintillation crystal array 103 may be the same or different. The materials and arrangement of the scintillation crystal bars of the scintillation crystal array 109 and the scintillation crystal array 103 may be the same or different.

[0097] Of course, the present disclosure does not impose any limitation on the number of detection collimation units, the number of scintillation crystals, the number of imaging detection units, etc.

[0098] In addition, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or methods mentioned in the embodiments, and those skilled in the art can simply change or replace them.

[0099] It should be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present disclosure. And the shapes and sizes of the components in the figures do not reflect the actual size and proportion, but only illustrate the contents of the embodiments of the present disclosure. In addition, in the claims, any reference symbols between brackets should not be constructed as limitations on the claims.

[0100] Furthermore, the word "comprising" or "including" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0101] The ordinal numbers used in the specification and claims, such as "first", "second", "third", etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element and another element, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish a component with a certain name from another component with the same name.

[0102] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, the various features of the present disclosure are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the following intention: the claimed disclosure requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the disclosed aspects are less than all the features of the single embodiment disclosed above. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, with each claim itself serving as a separate embodiment of the present disclosure.

[0103] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A precise positioning gamma photon detection unit for determining the deposition position of incident gamma photons in the detection unit, characterized in that: include: A scintillation crystal array, the scintillation crystal array comprising a side surface and two end surfaces at both ends of the side surface, the two end surfaces are respectively a photon incident surface and an exit surface; A plurality of optoelectronic devices, wherein the plurality of optoelectronic devices are arranged on the side surface of the scintillation crystal array and surround the side surface; The scintillation crystal array includes four sides. In the scintillation crystal array, for any scintillation crystal bar, there is at least one photoelectric device on the four sides of the scintillation crystal array, which can receive the scintillation photons emitted by the one scintillation crystal bar and pass through other scintillation crystal bars and the bonding materials between the scintillation crystal bars to reach the photoelectric device and output electrical signals.

2. The detection unit according to claim 1, characterized in that: The scintillation crystal array is arranged in a cube or a cuboid as a whole, including two opposite end faces and the side faces between the two end faces, one of the two end faces is the incident face of the gamma photons, and the other is the exit face of the gamma photons.

3. The detection unit according to claim 1, characterized in that: The scintillation crystal array comprises a plurality of spliced ​​or relatively fixed scintillation crystal strips, and the splicing material used is a resin light guide or a reflective film.

4. The detection unit according to claim 2, characterized in that: The scintillation crystal array comprises at least two scintillation crystal bars made of different materials.

5. The detection unit according to claim 3, characterized in that: The difference between the refractive index of the bonding material between the scintillation crystal strips and the refractive index of the scintillation crystal material does not exceed 50%, and the bonding material allows the scintillation photons emitted from the scintillation crystal to pass through.

6. The detection unit according to claim 1, characterized in that: After being emitted by the corresponding scintillation crystal bar, the scintillation photons pass through different effective paths in any direction before passing through a number of scintillation crystal bars and being received by a number of optoelectronic devices.

7. The detection unit according to claim 1, characterized in that: The scintillation photons are received by a plurality of photoelectric devices and output electrical signals. When gamma photons are incident on different scintillation crystal bars, the plurality of photoelectric devices output electrical signals with different amplitudes. The weights of the electrical signals output by the plurality of photoelectric devices are calculated to confirm the deposition position of the scintillation crystal bar where the gamma photons are received.

8. A gamma photon detection device, characterized in that: The gamma photon detection device comprises at least two detection units as described in any one of claims 1 to 7; wherein, The detection device further comprises a plurality of detection collimation unit layers arranged in multiple layers, in parallel, in staggered arrangement or in overlapping arrangement along the incident direction of the gamma photons; wherein the plurality of detection collimation unit layers are arranged front and back along the incident direction of the gamma photons; The plurality of detection collimation unit layers include a plurality of imaging detection units, and the imaging detection units include a plurality of scintillation crystals. There is at least one scintillation crystal on one of the imaging detection units, which can ensure that the gamma photons emitted from a point in the imaging field of view do not pass through any optoelectronic devices and / or circuit board materials on the transmission path of a scintillation crystal that is incident on the last imaging detection unit. The last imaging detection unit layer is the imaging detection unit to which the gamma photons are last incident among the plurality of imaging detection units.

9. A method for determining the position of a gamma photon by using the electrical signals output by a plurality of photoelectric devices of the precise positioning gamma photon detection unit according to any one of claims 1 to 7, characterized in that: include: During the calibration process, a pencil-shaped gamma photon beam is used to scan each scintillation crystal one by one, and the signal E on all optoelectronic devices is calculated when the gamma photon enters each scintillation crystal. i , i is the photoelectric device number; according to E i Calculate the weight position reference value x c,i and c,i , , , where w x,i and w y,i is a preset value; and the calibrated { , }Pre-save; During the acquisition process, when a gamma photon is received, the weight position reference value x' corresponding to the gamma photon is calculated c and y' c ; In the pre-stored { , } to find the value that matches x' c and y' c The closest and , so that the corresponding scintillation crystal position is used as the incident position of the gamma photon.

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