CN114010211A - Gamma camera and imaging method - Google Patents

Gamma camera and imaging method Download PDF

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CN114010211A
CN114010211A CN202111168025.9A CN202111168025A CN114010211A CN 114010211 A CN114010211 A CN 114010211A CN 202111168025 A CN202111168025 A CN 202111168025A CN 114010211 A CN114010211 A CN 114010211A
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马天予
刘亚强
吕振雷
胡一凡
张德斌
刘辉
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Tsinghua University
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Abstract

A gamma camera and an imaging method, the gamma camera comprising: the detection module comprises a plurality of layers of detection structures, each layer of detection structure comprises a plurality of detection units, and each detection unit is used for receiving incident gamma photons and obtaining the projection of the gamma photons; and the image reconstruction module is used for respectively selecting partial projections to reconstruct according to different imaging requirements to obtain a gamma photon three-dimensional distribution map meeting the different imaging requirements. The gamma camera can selectively acquire the projections with higher spatial resolution, or higher sensitivity, or different visual field ranges after completing one-time scanning data acquisition, so as to meet the requirements of different imaging indexes as much as possible, and reduce the operation time and the operation steps.

Description

Gamma camera and imaging method
Technical Field
The present disclosure relates to the field of radiation detection technologies, and in particular, to a gamma camera and an imaging method.
Background
With the development of nuclear medicine, the clinical application of nuclide imaging technology has become more and more extensive in recent years. The gamma camera and the SPECT device developed on the basis of the principle thereof are widely applied to the disease diagnosis and examination of various organs such as heart and cerebral vessels, tumors, thyroid glands, livers, kidneys and the like.
The traditional gamma camera and SPECT are provided with a conventional parallel hole collimator to collimate gamma rays, so that the system has poor performance indexes such as spatial resolution, sensitivity and the like, is severely restricted by distance factors, and is difficult to obtain essential performance improvement. In clinical diagnosis in nuclear medicine department, aiming at different organs or clinical disease applications, index performances with different resolutions and sensitivities are obtained by replacing different types of parallel hole collimators, and the energy range responses of different collimators are different. For example, the low-energy high-resolution collimator has a higher resolution but a lower sensitivity than the low-energy general collimator, and is relatively suitable for diseases requiring high focus location diagnosis and definition, and the high-energy general collimator is suitable for marking a scan with higher radionuclide energy but has a lower resolution. However, almost all collimators cannot simultaneously cover most of the clinical scanning needs, which makes the collimator frequent changes by the physician during the clinical work.
Disclosure of Invention
In view of the above, the present invention provides a gamma camera and an imaging method to at least partially solve the above technical problems.
One aspect of the present disclosure provides a gamma camera including: the detection module comprises a plurality of layers of detection structures, each layer of detection structure comprises a plurality of detection units, and each detection unit is used for receiving incident gamma photons and obtaining the projection of the gamma photons; and the image reconstruction module is used for respectively selecting partial projections for reconstruction according to different imaging requirements to obtain a gamma photon three-dimensional distribution map meeting the different imaging requirements.
Optionally, the relative distance and the relative alignment position between the detection structures of each layer of the detection module are adjustable, and the detection structures of each layer and the detection units of each layer can be detached and installed.
Optionally, the image reconstruction module sets first weights for projections obtained by different detection units of each layer of the detection structure, sets second weights for sets of projections obtained by the detection structure of each layer, and adjusts the first weights and the second weights to select the projections meeting different requirements.
Optionally, the detection units each include a scintillation crystal and a corresponding photoelectric conversion device, where the scintillation crystal may be a plurality of scintillation crystal strips distributed in a three-dimensional space array, a single scintillation crystal block, or a plurality of scintillation crystal blocks, and the photoelectric conversion device is a plurality of photomultiplier tubes, or position-sensitive photomultiplier tubes, or a plurality of avalanche type photodiodes, or a plurality of silicon photomultiplier devices, or a plurality of multi-pixel photon counters; or the detection unit is a semiconductor detector; the detection units are not identical in composition and size.
Optionally, the apparatus further comprises a porous shielding plate, which is detachably or fixedly arranged at the front end of the detection module, and is used for limiting the incidence direction of the gamma photons.
Optionally, the method further comprises: and the mechanical adjusting module is used for adjusting the distance between the measured object of the gamma photons and the detecting module, adjusting the relative distance and the relative alignment position between the detecting structures on each layer, and disassembling and assembling any one of the detecting structures and the detecting unit.
Optionally, the method further comprises: and the display module is used for displaying the three-dimensional distribution image of the gamma photons in real time.
Another aspect of the present disclosure provides an imaging method applied to the gamma camera according to the first aspect, including: receiving incident gamma photons and obtaining projections of the detection units incident to each layer of the detection structure; and respectively selecting partial projections to reconstruct according to different imaging requirements to obtain the gamma photon three-dimensional distribution map meeting the different imaging requirements.
Optionally, the respectively selecting a part of the projections to reconstruct according to different imaging requirements to obtain a gamma photon three-dimensional distribution map meeting the different imaging requirements includes: respectively setting first weights for projections obtained by different detection units of each layer of the detection structure, and respectively setting second weights for a set of projections obtained by each layer of the detection structure; adjusting the first weight and the second weight according to different imaging requirements to realize selection of the projection meeting different requirements; reconstructing based on the selected projection to obtain sensitivity, resolution, edge resolution, and three-dimensional distribution of the gamma photons of the imaging field of view.
Optionally, the method further comprises: adjusting the number, the composition and the relative position of each layer of detection structure and each detection unit of the gamma camera, and/or adjusting the aperture ratio of a shielding plate, and/or adjusting the distribution density or the material density of scintillation crystal strips when the detection units comprise the scintillation crystal strips so as to improve the imaging quality of the gamma camera.
The at least one technical scheme adopted in the embodiment of the disclosure can achieve the following beneficial effects:
the gamma camera provided by the disclosure has a multi-layer detection structure, the projection can be acquired through one-time scanning data, the first weight is respectively set for the projection acquired by different detection units of the detection structure of each layer, the second weight is respectively set for the set of the projection acquired by the detection structure of each layer for reconstruction, the projection with higher spatial resolution, or with higher sensitivity, or with different visual field ranges is selectively acquired, the requirements of different imaging indexes are met as much as possible, the operation time and the operation steps are reduced, and the imaging efficiency is improved.
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For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
fig. 1 schematically shows a block diagram of a gamma camera according to an embodiment of the present disclosure;
FIG. 2 schematically illustrates a structural schematic of a detection module according to an embodiment of the disclosure;
FIG. 3 schematically illustrates an imaging field of view schematic of a detection module according to an embodiment of the disclosure;
FIG. 4 schematically illustrates a structural schematic of a detection module according to an embodiment of the present disclosure;
FIG. 5 schematically illustrates a structural schematic of a detection module according to another embodiment of the present disclosure;
FIG. 6 schematically illustrates a structural schematic of a detection module according to another embodiment of the present disclosure;
FIG. 7 schematically illustrates a structural schematic of a detection module according to another embodiment of the present disclosure;
fig. 8 schematically shows a structural schematic diagram of a detection module according to another embodiment of the present disclosure.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present disclosure. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the disclosure. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.
All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.
Fig. 1 schematically shows a block diagram of a gamma camera according to an embodiment of the present disclosure.
As shown in fig. 1, an embodiment of the present disclosure provides a gamma camera 100, including: a detection module 110 and an image reconstruction module 120. The detection module 110 includes a plurality of detection structures, each detection structure includes a plurality of detection units 111, and each detection unit 111 is configured to receive an incident gamma photon and obtain a projection of the gamma photon. And the image reconstruction module 120 is configured to select partial projections respectively according to different imaging requirements to reconstruct, so as to obtain a gamma photon three-dimensional distribution map meeting the different imaging requirements.
In the embodiment of the present disclosure, based on the multi-layer detection structure of the detection module 110, multiple types of projection data can be simultaneously obtained in one-time gamma photon image data acquisition, so that the operation times, operation time and operation steps of data acquisition are reduced, and the imaging efficiency and flexibility are improved.
The relative distance and the relative alignment position between the detection structures of each layer of the detection module 110 are adjustable, and the detection structures and the detection units of each layer can be detached and installed.
In the embodiment of the present disclosure, the image reconstruction module sets first weights for projections obtained by different detection units 111 of each layer of the detection structure, sets second weights for sets of projections obtained by each layer of the detection structure, and adjusts the first weights and the second weights to realize selection of the projections meeting different requirements. For example, when the edge resolution of the gamma photon three-dimensional distribution map needs to be improved, the first weight of the projection obtained by the detection unit 111 in which at least one layer of detection structure is relatively close to the edge may be increased, and accordingly, the edge resolution of the reconstructed gamma photon three-dimensional distribution map may be correspondingly increased; when a three-dimensional reconstruction with a smaller imaging field of view is required, since the imaging field of view of the detection unit 111 that is farther back is smaller, the second weight of at least one layer of detection structure near the front end of the detection module 110 may be adjusted to be higher, and the second weight of at least one layer of detection structure near the back end of the detection module 110 may be adjusted to be lower, so as to reduce the imaging field of view of the gamma photon three-dimensional distribution map.
The selection and regulation rules of different performance indexes are as follows:
(1) sensitivity: selecting a projection obtained by a detection structural layer relatively close to an object to be detected for reconstruction, or improving the weight coefficient of a corresponding layer, or changing the detection unit 111 into a structure with more densely distributed scintillation crystal strips 21, or changing the scintillation crystals 21 of the detection unit 111 into a material with higher density, or crystals with larger size, or changing the scintillation crystals 21 into a shielding plate with relatively larger aperture ratio, or removing the shielding plate, so that the system sensitivity is improved; on the contrary, the projection obtained by the detection structure layer relatively far away from the detected object is selected for reconstruction, or the weight coefficient of the corresponding layer is reduced, or the detection unit 111 is changed into a structure with the scintillation crystal strips 21 distributed more sparsely, or the scintillation crystal 21 of the detection unit 111 is changed into a material with lower density, or a crystal with smaller size, or a shielding plate with relatively smaller aperture ratio is changed, or the shielding plate is removed, so that the system sensitivity is reduced;
(2) resolution ratio: selecting a projection obtained by a detection structural layer relatively close to the detected object to reconstruct, or reducing the weight coefficient of a corresponding layer, or replacing the projection with a shielding plate with relatively large aperture ratio to perform direction collimation, or changing the detection unit 111 into a structure with more sparsely distributed scintillation crystal strips 21, so that the resolution is reduced; on the contrary, the projection obtained by the detection structure layer relatively far away from the detected object is selected for reconstruction, or the weight coefficient of the corresponding layer is improved, or the shielding plate with relatively smaller aperture ratio is replaced for direction collimation, or the detection unit 111 is changed into a structure with more densely distributed scintillation crystal strips 21, so that the resolution is improved.
(3) Edge resolution: the projections obtained by the detection units 111 relatively close to the edge in different detection structure layers are selected for reconstruction, or the corresponding weight coefficients are improved, or the number of the detection units 111 close to the edge is increased, or the distance between the detection units 111 close to the edge is reduced, and the edge field resolution is improved; on the contrary, the projections obtained by the detection units 111 relatively far away from the edge in different detection structure layers are selected for reconstruction, or the corresponding weight coefficients are reduced, or the number of the detection units 111 near the edge is reduced, or the distance between the detection units 111 near the edge is increased, and the resolution of the edge field is reduced;
(4) imaging field of view: selecting the projection obtained by the detection structural layer relatively close to the detected object for reconstruction, or selecting the projection obtained by the detection structural layer relatively far from the detected object for reconstruction, or selecting the shielding plate for limiting the direction range of the incident photon to be smaller, and the imaging field of view of the projection to be relatively larger, or selecting the projection obtained by the detection structural layer relatively far from the detected object for reconstruction, or limiting the direction range of the incident photon to be larger, and the imaging field of view of the shielding plate to be relatively smaller;
based on the selection and adjustment rules of the different performance indexes, the first weights of the detection units 111 and the second weights of the detection structures of the layers are adjusted, so that the influence of the projections obtained by the detection structures of the layers and the projections of the detection units 111 of each detection structure of each layer on the three-dimensional distribution diagram of the reconstructed gamma photons is enlarged or reduced, and the three-dimensional distribution diagram with different sensitivity, resolution and visual field indexes is displayed.
It should be noted that, in one detection module 110, a plurality of multi-layer detection structures may be included, so that a plurality of radiation detection structures such as a ring, a polygon, a linear type, a curved type, an arc shape, etc. may be configured, and each multi-layer detection structure is respectively used for detecting gamma photons with different angles, so as to further improve the imaging efficiency.
Fig. 2 schematically illustrates a structural schematic diagram of the detection module 110 according to an embodiment of the present disclosure.
As shown in fig. 2, the detection module 110 includes a multi-layered detection structure, each of which includes a plurality of detection units 111, and each of the detection units 111 may include a scintillator crystal 21 and a photoelectric conversion device 22. Wherein the scintillation crystal 21 is configured to receive incident gamma photons and convert the gamma photons into visible light signals, the photoelectric conversion device 22 is configured to receive the visible light signals and convert the visible light signals into electrical signals, and then convert the electrical signals into digital signals, and further project the digital signals, and furthermore, each detection unit 111 may be a semiconductor detector. In the embodiment of the present disclosure, the distance between each layer of the detecting structures can be adjusted relatively, the relative alignment position can be adjusted, any layer can be detached, and any detecting unit 111 can be detached and installed, and the composition and size of any detecting unit 111 may not be completely the same.
In the embodiment of the present disclosure, a high-aperture-ratio shielding plate 23 may be installed at the front end of the detection module 110 to define the incident direction of the gamma photons. The shielding plate 23 is made of heavy metal and can be freely detached. Optionally, the shielding plates 23 with different aperture ratios, different aperture sizes and different materials can be replaced according to performance requirements, and the collimator can be replaced by a parallel hole collimator, a coding plate collimator and a multi-pinhole collimator with different parameters. Preferably, the aperture ratio of the shielding plate, the size of each hole and the hole spacing between the holes are adjustable, and the sizes and the spacings of the holes in different areas on the shielding plate are respectively adjusted according to actual requirements and the selection and adjustment rules of different performance indexes, so as to improve the imaging quality.
According to the detection module 110 shown in fig. 2, when gamma photons released by a radioactive imaging nuclide in a human body 24 pass through the detection module 110 along an incident direction, the gamma photons pass through the shielding plate 23 and the blocking of each layer of detection structure of the detection module 110, and cannot pass through the detection module with a certain probability (so-called photon direction collimation), and the image reconstruction module can reversely deduce the three-dimensional distribution of the gamma photons of the human body based on the projection of the gamma photon statistics received by each detection unit 111 and the distribution probability transmission matrix theoretically received by the detection units 111 based on the reconstruction algorithm.
Optionally, the detection module 110 may further include: the mechanical adjusting module is used for adjusting the relative distance between the measured object of the gamma photons and the detecting module 110, adjusting the relative distance and the relative alignment position between the detecting structures on each layer, and enabling any detecting structure and any detecting unit 111 to be detachable and mountable, and the composition and the size of any detecting unit 111 can not be completely the same.
Optionally, the gamma camera 100 may further include: and the display module is used for displaying the three-dimensional distribution image of the gamma photons in real time, and a user can adjust the display module in time according to the display effect and the requirement.
Fig. 3 schematically illustrates an imaging field of view schematic of the detection module 110 according to an embodiment of the disclosure.
As shown in fig. 3, each layer of the detection structure includes a plurality of detection units 111, each detection unit 111 includes a scintillation crystal 21 and a corresponding photoelectric conversion device 22, the imaging fields of view of different layers with respect to the shielding plate 23 are different, and the imaging field of view of the detection unit 111 of the later layer is smaller; due to the collimation effect and the distance amplification effect of the shielding plate 23 and the front-layer detector, the imaging spatial resolution of the detector on the later layer is better; the same reason will result in lower detector imaging sensitivity for later layers.
Alternatively, the scintillation crystal 21 can be a plurality of scintillation crystal strips distributed in a three-dimensional array, and can also be a single scintillation crystal block or a plurality of scintillation crystal blocks.
Alternatively, the photoconversion device 22 may be a plurality of photomultiplier tubes, or a position sensitive photomultiplier tube, or a plurality of avalanche type photodiodes, or a multi-chip silicon photomultiplier device, or a multi-chip multi-pixel photon counter.
Alternatively, the detection unit 111 may be a semiconductor detector.
Fig. 4 to 7 respectively schematically show structural diagrams of the detection module 110 according to one embodiment of the present disclosure.
Fig. 4 schematically shows a structural diagram of the detection module 110 according to one embodiment of the present disclosure, in which the scintillation crystal 21 is a multi-block scintillation crystal block, and the photoelectric conversion device 22 is a plurality of photomultipliers, or position-sensitive photomultipliers, or a plurality of avalanche type photodiodes, or a plurality of silicon photomultipliers, or a plurality of multi-pixel photon counters, distributed in an area array.
Fig. 5 schematically shows a structural diagram of a detection module 110 according to another embodiment of the present disclosure, and the scintillation crystal 21 is a large-area bulk block of scintillation crystals. The photoelectric conversion device 22 is a plurality of discretely distributed photomultiplier tubes, or position sensitive photomultiplier tubes, or a plurality of avalanche type photodiodes, or a multi-chip silicon photomultiplier device, or a multi-chip multi-pixel photon counter.
Fig. 6 schematically shows a structural diagram of a detection module 110 according to another embodiment of the present disclosure, where the scintillation crystals 21 are a plurality of scintillation crystal strips distributed in a three-dimensional array, the photoelectric conversion devices 22 are a plurality of discretely distributed photomultipliers, or position-sensitive photomultipliers, or a plurality of avalanche type photodiodes, or a plurality of silicon photomultipliers, or a plurality of multi-pixel photon counters, or the detection units 111 are discretely distributed semiconductor detectors.
Fig. 7 schematically shows a structural diagram of the detection module 110 according to another embodiment of the present disclosure, in which the scintillation crystals 21 are a plurality of scintillation crystal strips distributed in a three-dimensional array, and the photoelectric conversion device 22 is an array of a plurality of photomultipliers distributed in an area array, or a position-sensitive photomultiplier, or a plurality of avalanche type photodiodes, or a plurality of silicon photomultipliers, or a plurality of multi-pixel photon counters.
Fig. 8 schematically shows a structural diagram of a detection module 110 according to another embodiment of the present disclosure, where the composition and number of each detection unit 111 are not completely the same, the scintillation crystals 21 are a plurality of scintillation crystal strips distributed in a three-dimensional array, the density or material density of the crystal strips of the detection units 111 may be different, and the photoelectric conversion device 22 is a plurality of photomultipliers distributed in an area array, or a position-sensitive photomultiplier, or a plurality of avalanche photodiodes, or a plurality of silicon photomultipliers, or a plurality of multi-pixel photon counter arrays. Compared with fig. 7, the detecting units 111 of each layer of the detecting module shown in fig. 8 can be arbitrarily detached and installed, the relative spacing between the detecting units 111 can be adjusted, the detecting units 111 can be replaced by modules with different density of scintillation crystal strips or different material density, and the aperture ratio of the shielding plate can be partially adjusted relatively.
According to the gamma camera 100 provided by the embodiment of the present disclosure, three-dimensional distribution images of radioactive substances with different spatial resolutions, different imaging sensitivities, different imaging fields of view, and different energies can be obtained through one-time data acquisition, so as to simultaneously meet the requirements of imaging of different organs, thereby reducing the operation time and operation steps of a user.
Another aspect of the present disclosure also provides an imaging method of a gamma camera as shown in fig. 1, the method including S1 to S2.
S1, receiving the incident gamma photons and obtaining projections incident on the respective detection units 111 of each layer of the detection structure.
And S2, respectively selecting partial projections for reconstruction according to different imaging requirements, and obtaining the gamma photon three-dimensional distribution map meeting the different imaging requirements.
Specifically, S2 includes S201 to S203.
S201, respectively setting first weights for the projections obtained by the different detection units 111 of each layer of the detection structure, and respectively setting second weights for the sets of the projections obtained by each layer of the detection structure.
S202, adjusting the first weight and the second weight according to different imaging requirements to realize selection of the projection meeting different requirements.
Specifically, the weight assignment method is as follows:
P＝[α1×P1；α2×P2；...αi×Pi...；αN×PN]；
Pi＝{β1×Pi_1，β2×Pi_2，...，βj×Pi_j，...βM×Pi_M}；
wherein, Pi_jRepresents the projection of the jth detection unit 111 under the ith detector, i 1, 2.. i.., N, j 1, 2.. j.., M, PiRepresents a set of projections, β, of the M detection units 111 comprised by the ith layerjRepresenting a first weight, alpha, of a projection of the jth detection unit 111 of the ith slice detector during image reconstructioniRepresenting second weights of the i-layer detector projections during image reconstruction.
By adjusting the first weight and the second weight, the influence of the projections obtained by each layer of detection structure and the projection of each detection unit 111 specific to each layer of detection structure on the three-dimensional distribution diagram of the reconstructed gamma photons is enlarged or reduced, so as to obtain the display of the three-dimensional distribution diagram with different sensitivity, resolution and visual field indexes.
S203, reconstructing based on the selected projection to obtain three-dimensional distribution of the gamma photons with different sensitivity, resolution, edge resolution and imaging visual field.
The reconstruction method can adopt a statistical iterative reconstruction algorithm formula:
Figure BDA0003288952040000101
wherein p ismIs the pixel value of the photon on the m-th detection unit 111, cmnFor obtaining the value of the m-th row and n-th column in the corresponding system transmission matrix, pm＝Pi_j_m，cmn＝Ci_j_m_nThe m-th detection position refers to the m-th minimum detection unit 111, P of the j-th detection unit 111 under the i-th layer detectori_j_mIs the pixel value, C, of the m-th minimum detection unit 111 of the j-th detection unit 111 under the i-th layer detectori_j_m_nRepresenting the contribution of the nth point on the image to the pixel of the mth smallest detection unit 111 of the jth detection unit 111 under the ith layer detector,
Figure BDA0003288952040000102
representing the pixel value of the nth pixel on the image at the kth iteration, representing the contribution of the nth point on the image to the mth detection position;
Figure BDA0003288952040000103
representing the value of the j-th pixel on the image at the (k + 1) -th iteration.
According to the method, by using the projections acquired by the detection module 110 of the multi-layer detection structure provided by the disclosure, the three-dimensional distribution images of the radioactive substances with different spatial resolutions, different imaging sensitivities and different imaging fields can be acquired by adjusting the first weight and the second weight of each projection.
According to the detection module 110 shown in fig. 8, the relative distance and the relative alignment position between the detection structures of each layer of the detection module 110 are adjustable, the detection structures and the detection units 111 of each layer can be detached and installed, the aperture ratio, the aperture position, and the size of the hole of the shielding plate can be adjusted, each detection unit 111 can also be different in composition and structure, and according to the selection and adjustment rules of different performance indexes of the detection module 110, when the gamma camera 100 is used for imaging, the imaging method can further include operation S3:
s3, adjusting the number, composition, and relative position of each layer of the detection structure and each detection unit 111 of the gamma camera 100, and/or adjusting the aperture ratio of the shielding plate, and/or adjusting the distribution density or material density of the scintillation crystal 21 when the detection unit 111 includes the scintillation crystal 21, so as to improve the imaging quality of the gamma camera 100.
According to the selection and adjustment rules of different performance indexes of the detection module 110, by adjusting the structure of the gamma camera 100, the performance of each aspect of the image obtained based on projection reconstruction can be adjusted correspondingly, and the imaging quality is further improved. Those skilled in the art will appreciate that various combinations and/or combinations of features recited in the various embodiments and/or claims of the present disclosure can be made, even if such combinations or combinations are not expressly recited in the present disclosure. In particular, various combinations and/or combinations of the features recited in the various embodiments and/or claims of the present disclosure may be made without departing from the spirit or teaching of the present disclosure. All such combinations and/or associations are within the scope of the present disclosure.
While the disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Accordingly, the scope of the present disclosure should not be limited to the above-described embodiments, but should be defined not only by the appended claims, but also by equivalents thereof.

Claims (10)

1. A gamma camera, comprising:
the detection module comprises a plurality of layers of detection structures, each layer of detection structure comprises a plurality of detection units, and each detection unit is used for receiving incident gamma photons and obtaining the projection of the gamma photons;
and the image reconstruction module is used for respectively selecting partial projections for reconstruction according to different imaging requirements to obtain a gamma photon three-dimensional distribution map meeting the different imaging requirements.
2. The gamma camera according to claim 1, wherein the relative distance and relative alignment position between the detection structures of the detection module are adjustable, and each detection structure and each detection unit are detachable and attachable.
3. The gamma camera according to claim 1, wherein the image reconstruction module sets a first weight for each layer of the projection obtained by the different detecting units of the detecting structure, sets a second weight for each layer of the set of the projection obtained by the detecting structure, and adjusts the first weight and the second weight to achieve the selection of the projection meeting the different requirements.
4. The gamma camera according to claim 1, wherein the detection units each comprise a scintillation crystal and a corresponding photoelectric conversion device, wherein the scintillation crystal is a plurality of scintillation crystal strips distributed in a three-dimensional space array, a single scintillation crystal block or a plurality of scintillation crystal blocks, and the photoelectric conversion device is a plurality of photomultiplier tubes, or position sensitive photomultiplier tubes, or a plurality of avalanche type photodiodes, or a plurality of silicon photomultiplier devices, or a plurality of multi-pixel photon counters;
or the detection unit is a semiconductor detector;
the composition and size of each of the detection units are not identical.
5. The gamma camera of claim 1, further comprising a perforated shutter removably or attached to the front end of the detection module for defining the direction of incidence of the gamma photons.
6. The gamma camera of claim 2, further comprising:
and the mechanical adjusting module is used for adjusting the distance between the measured object of the gamma photons and the detecting module, adjusting the relative distance and the relative alignment position between the detecting structures on each layer, and disassembling or assembling any one of the detecting structures and the detecting unit.
7. The gamma camera of claim 1, further comprising:
and the display module is used for displaying the three-dimensional distribution image of the gamma photons in real time.
8. An imaging method applied to the gamma camera according to any one of claims 1 to 7, comprising:
receiving incident gamma photons and obtaining projections of all detection units incident to each layer of detection structure;
and respectively selecting partial projections to reconstruct according to different imaging requirements to obtain the gamma photon three-dimensional distribution map meeting the different imaging requirements.
9. The imaging method of claim 8, wherein the selecting a portion of the projections for reconstruction according to different imaging requirements to obtain a three-dimensional gamma photon distribution map satisfying the different imaging requirements comprises:
respectively setting first weights for projections obtained by different detection units of each layer of the detection structure, and respectively setting second weights for a set of projections obtained by each layer of the detection structure;
adjusting the first weight and the second weight according to different imaging requirements to realize selection of the projection meeting different requirements;
and reconstructing based on the selected projection to obtain the three-dimensional distribution of the gamma photons with different sensitivity, resolution, edge resolution and imaging visual field.
10. The imaging method of claim 8, further comprising:
adjusting the number, the composition and the relative position of each layer of detection structure and each detection unit of the gamma camera, and/or adjusting the aperture ratio of a shielding plate, and/or adjusting the distribution density or the material density of scintillation crystal strips when the detection units comprise the scintillation crystal strips so as to improve the imaging quality of the gamma camera.
CN202111168025.9A 2021-09-30 2021-09-30 Gamma camera and imaging method Pending CN114010211A (en)

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