WO2023124459A1 - 伽马相机成像方法和装置 - Google Patents

伽马相机成像方法和装置 Download PDF

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WO2023124459A1
WO2023124459A1 PCT/CN2022/127110 CN2022127110W WO2023124459A1 WO 2023124459 A1 WO2023124459 A1 WO 2023124459A1 CN 2022127110 W CN2022127110 W CN 2022127110W WO 2023124459 A1 WO2023124459 A1 WO 2023124459A1
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energy
image
gamma camera
radioactive
branch
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French (fr)
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图雅高娃
胡春煊
赵崑
靳增雪
马志丹
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Nuctech Co Ltd
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Nuctech Co Ltd
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    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/50—Image enhancement or restoration using two or more images, e.g. averaging or subtraction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/167—Measuring radioactive content of objects, e.g. contamination
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/29—Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation
    • G01T1/2914—Measurement of spatial distribution of radiation
    • G01T1/2921—Static instruments for imaging the distribution of radioactivity in one or two dimensions; Radio-isotope cameras
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/36—Measuring spectral distribution of X-rays or of nuclear radiation spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/36—Measuring spectral distribution of X-rays or of nuclear radiation spectrometry
    • G01T1/362—Measuring spectral distribution of X-rays or of nuclear radiation spectrometry with scintillation detectors
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/10—Segmentation; Edge detection
    • G06T7/11—Region-based segmentation
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T7/00—Image analysis
    • G06T7/10—Segmentation; Edge detection
    • G06T7/136—Segmentation; Edge detection involving thresholding
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T2207/00—Indexing scheme for image analysis or image enhancement
    • G06T2207/20—Special algorithmic details
    • G06T2207/20212—Image combination
    • G06T2207/20221—Image fusion; Image merging
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention relates to the technical field of gamma cameras, in particular to a gamma camera imaging method and device.
  • the gamma camera is used in the field of nuclear safety and nuclear detection.
  • the main function is to perform dynamic and static imaging of the radiation field in the radioactive material contaminated area, and to fuse it with the optical imaging image to obtain the distribution information of the radioactive material.
  • Existing gamma cameras usually use a linear data processing method, that is, the received signals are not differentiated, and the projection image restoration and original image reconstruction are performed on the signals of all effective energy segments together. Because of quantization loss and approximation processing in the data processing process, after reconstructing the image, there are often statistical fluctuations and shadows in the background of bright spots. Then use brightness threshold or saliency threshold to filter the image area, and only select some obvious imaging images to fuse with the optical image.
  • a gamma camera imaging method comprising: selecting one or more of each radioactive substance from the energy spectrum of one or more radioactive substances captured by the gamma camera The energy range is used as one or more monitoring energy regions of the radioactive substance; image reconstruction is performed on the monitoring energy regions of each radioactive substance in the one or more radioactive substances; each obtained through the image reconstruction The images are normalized; and the normalized images are superimposed to form a composite image.
  • the selection includes: performing ergodic peak searching from the energy spectrum, and comparing the peak finding results with the energy of each branch of radioactive substances recorded in the predetermined nuclide library to determine the one or more Radioactive substances; for each of the one or more radioactive substances, the branch of the radioactive substance with a higher branch ratio or a lower energy branch is determined as one or more of the radioactive substance to be monitored branch; and for each branch in the one or more branches of each radioactive material, the energy range centered on the center energy of the branch and taking the half-maximum width of the corresponding spectral peak of the branch as the width is determined as One of one or more monitoring energy regions for the radioactive material.
  • the gamma camera imaging method further includes: for each image obtained through the image reconstruction, determining whether there is a closed area in each of the images; if there is a closed area in the image Next, if the ratio of the contrast between the closed area and the background area outside the closed area is smaller than a predetermined threshold, adaptively adjust the energy range of the monitoring energy area corresponding to the image.
  • the self-adaptive adjustment includes: gradually trying to expand or reduce the monitoring energy area to be adjusted with a predetermined energy step as a unit, until the closed area and the background area outside the closed area until the contrast reaches the predetermined threshold.
  • the gamma camera imaging method further includes: if there is no closed area in the image, discarding data corresponding to the monitored energy region of the image.
  • the gamma camera imaging method further includes: in the case that there is no closed area in the image, after a predetermined time, discarding the data of the monitored energy region corresponding to the image.
  • a gamma camera imaging device including: a selection module, selecting one or more of each radioactive substance from the energy spectrum of one or more radioactive substances captured by the gamma camera energy ranges as one or more monitoring energy regions of the radioactive substance; the image reconstruction module performs image reconstruction respectively for the monitoring energy regions of each radioactive substance in the one or more radioactive substances; the normalization module, normalizing each image obtained through the image reconstruction; and an overlay module, overlaying each normalized image to form a composite image.
  • the selection module includes: a peak-finding module, which performs traversal peak-finding from the energy spectrum, and compares the peak-finding result with the energy of each branch of the radioactive material recorded in the predetermined nuclide library to determine the one or a plurality of radioactive substances; the branch determination module, for each radioactive substance in the one or more radioactive substances, determines the branch of the radioactive substance with a higher branch ratio or a lower energy branch as the main component of the radioactive substance one or more branches for monitoring; and an energy zone determination module, for each of the one or more branches of each radioactive material, centering on the central energy of the branch and corresponding to the spectrum of the branch The half maximum width of the peak is determined as one of the one or more monitoring energy regions of the radioactive material.
  • a peak-finding module which performs traversal peak-finding from the energy spectrum, and compares the peak-finding result with the energy of each branch of the radioactive material recorded in the predetermined nuclide library to determine the one or a plurality of radioactive
  • the image reconstruction module further includes: a closed area determination module, for each image obtained through the image reconstruction, determines whether there is a closed area in each of the images; and an energy zone adjustment module, in the If there is a closed area in the image, if the contrast ratio of the closed area to the background area outside the closed area is smaller than a predetermined threshold, adaptively adjust the energy range of the monitoring energy area corresponding to the image.
  • the energy region adjustment module is configured to: gradually try to expand or reduce the monitoring energy region to be adjusted with a predetermined energy step as a unit, until the closed region is in contact with the background region outside the closed region until the contrast reaches the predetermined threshold.
  • the image reconstruction module further includes a discarding module configured to discard the data of the monitored energy region corresponding to the image if there is no closed area in the image.
  • the discarding module is configured to discard the data of the monitored energy region corresponding to the image after a predetermined time if there is no closed area in the image.
  • a gamma camera imaging device including: a memory storing instructions; a processor configured to execute the instructions stored in the memory to perform the above-mentioned gamma camera imaging method.
  • a computer-readable storage medium storing instructions, which when executed by a processor cause the processor to execute the above gamma camera imaging method.
  • a gamma camera including any one of the gamma camera imaging devices described above.
  • the gamma camera imaging method and device can take all radioactive substances into account by separately analyzing each monitoring energy region of each radioactive substance, and reduce the background noise, thereby improving the SNR.
  • the gamma camera imaging method and device can only refresh the projection images of moving radioactive substances in the dynamic measurement mode, so that the imaging of moving substances and stationary substances does not affect each other.
  • Figure 1 shows a graphical representation of energy spectra captured by a gamma camera from three radioactive sources (Am241, Co57, Ba133);
  • Fig. 2 shows an example image obtained by reconstructing the energy spectra of the three radioactive sources (Am241, Co57, Ba133) in Fig. 1 by a gamma camera using a conventional method.
  • FIG. 3 illustrates a flow chart of a gamma camera imaging method according to an embodiment of the present application
  • Figure 4 shows a graphical representation of energy spectra captured by a gamma camera from three radioactive sources (Am241, Co57, Ba133);
  • Fig. 5 illustrates the example synthetic image that gamma camera uses the method of the embodiment of the present application to carry out image reconstruction to the energy spectrum of three radioactive sources (Am241, Co57, Ba133) of Fig. 4;
  • Figure 6 illustrates a graphical representation of an energy spectrum captured by a gamma camera from a high energy radioactive material such as Co60;
  • Fig. 7 shows a schematic diagram of the comparison between the images obtained by reconstructing images of two radioactive sources (Am241, Co57) using a conventional method with a gamma camera and the images obtained by reconstructing images of the same radioactive source using the method of the embodiment of the present application.
  • FIG. 8 illustrates a block diagram of a gamma camera imaging device according to an embodiment of the application.
  • FIG. 9 illustrates an example block diagram of a computing device that may be used to implement a gamma camera imaging device according to an embodiment of the application.
  • the gamma camera monitoring results are presented in images, and the distribution and types of radioactive substances can be judged by observing the images on the screen with human eyes. Therefore, whether radioactive substances can be imaged is the key to affecting the gamma camera monitoring results.
  • the basic condition for imaging is that the number of gamma events emitted by the radiation source exceeds a certain proportion of the environmental background gamma events from a statistical point of view, that is, only after the signal-to-noise ratio reaches a certain threshold can a more ideal image be obtained by statistical and image processing methods. analysis results.
  • the detection efficiency of high-energy particles is not high due to the limitation of the size and material of the detector.
  • the detection distance of traditional gamma cameras is usually not too far and the measurement time is relatively long.
  • Figure 1 shows a graphical representation of energy spectra captured by a gamma camera from three radioactive sources (Am241, Co57, Ba133).
  • Fig. 1 includes Fig. 1(a) and Fig. 1(b), wherein the horizontal axis represents energy in units of Tao value, and the vertical axis represents count value.
  • the energy spectrum region produced by Am241 is marked with a solid line frame
  • the energy spectrum region produced by Co57 is marked with a dashed line frame
  • the energy spectrum region produced by Ba133 is marked with a dotted line frame.
  • the light gray area provides valid information
  • the dark gray area provides noise information (in this example, only the omnipotent peak and no Compton scattering plate data were used as valid information for imaging).
  • the area of the light gray area reaches a certain ratio compared with the area of the dark gray area, the better imaging of the gamma camera can be guaranteed.
  • the brightness of the bright spots formed by each radioactive point source in the reconstructed image will also vary greatly.
  • the bright spots of weak sources are easily submerged in the statistical fluctuation background formed by strong sources. Since the brightness value is difficult to exceed the screening threshold, they will not be selected for fusion with optical images, or even if they can be selected for fusion with optical images , and its brightness is also very weak, which is difficult to observe with the naked eye.
  • Fig. 2 shows an example image obtained by reconstructing the energy spectra of the three radioactive sources (Am241, Co57, Ba133) in Fig. 1 by a gamma camera using a conventional method.
  • the abscissa and ordinate in the image are the pixel scale of the gamma camera imaging image.
  • this image only the bright spots represented by the two peaks of Am241 in the energy spectrum can be observed, but Co57 and Ba133 cannot be observed. Therefore, conventional methods fail to adequately represent information from all radioactive sources.
  • Embodiments according to the present application provide a gamma camera imaging method and device, which can make full use of the effective information of each radioactive source, and optimally display the distribution of radioactive substances in the field of view.
  • FIG. 3 illustrates a flowchart of a gamma camera imaging method according to an embodiment of the present application.
  • the gamma camera imaging method 100 includes: S101-S104.
  • step S101 one or more energy ranges of each radioactive substance are selected from the energy spectra of one or more radioactive substances captured by the gamma camera as one or more monitoring energy regions of the radioactive substance.
  • the selection of the monitoring energy region may include: performing traversal peak finding from the energy spectrum, comparing the peak finding result with the energy of each branch of the radioactive material recorded in the predetermined nuclide library, to Determining the one or more radioactive substances; for each radioactive substance in the one or more radioactive substances, determining the branch with higher branch ratio or lower energy among the branches of the radioactive substance as the branch of the radioactive substance the one or more branches to be monitored; and for each radioactive material, each of the one or more branches will be centered on the central energy of that branch and at the half-height of the corresponding spectral peak of that branch The wide energy range is determined as one of the one or more monitoring energy regions of the radioactive material.
  • one monitoring energy zone may be selected for one radioactive substance, or multiple monitoring energy zones may be selected, and the monitoring energy zones selected for different radioactive substances may also overlap.
  • two criteria are mainly considered, namely branch ratio and energy, because the detection efficiency of gamma camera detectors for high-energy gamma particles is very low, try to choose lower energy branch; because the higher the branch ratio, the more gamma particles produced by the same amount of radioactive material, so try to choose the branch with higher branch ratio.
  • branch ratio and energy because the detection efficiency of gamma camera detectors for high-energy gamma particles is very low, try to choose lower energy branch; because the higher the branch ratio, the more gamma particles produced by the same amount of radioactive material, so try to choose the branch with higher branch ratio.
  • step S102 image reconstruction is performed on the monitoring energy range of each radioactive substance in the one or more radioactive substances respectively.
  • step S102 commonly used correlation decoding methods or statistical decoding methods may be selected for image reconstruction as required.
  • the gamma camera imaging method further includes: for each image obtained through image reconstruction, determining whether there is a closed area in each image; if there is a closed area in the image, if the closed area If the contrast ratio of the area to the background area outside the closed area is less than a predetermined threshold, the energy range of the monitoring energy area corresponding to the image is adaptively adjusted.
  • the self-adaptive adjustment may include: gradually trying to increase or decrease the monitoring energy area to be adjusted with a predetermined energy step as a unit, until the closed area is close to the background area outside the closed area. until the contrast reaches the predetermined threshold.
  • the energy range of adaptive adjustment is determined by the resolution of the detector and the distance between adjacent peaks. Generally speaking, if the energy calibration of the gamma camera is relatively accurate, the degree of adaptive adjustment is not large. For example, generally 2 ⁇ 5 half-width ranges.
  • the gamma camera can work in static measurement mode and dynamic measurement mode.
  • the method according to the present application may further include: in the case that there is no closed area in the image, discarding the data of the monitoring energy region corresponding to the image.
  • the method according to the present application may further include: in the case that there is no closed area in the image, after a predetermined time, discarding the data of the monitoring energy region corresponding to the image. Since in the dynamic measurement mode, the dynamic movement of radioactive substances may cause closed areas to appear in the reconstructed image, therefore, the data is discarded only after there is no closed area after continuous observation for a predetermined time. By discarding the monitoring energy region data that cannot be imaged, not only the calculation amount can be reduced, but also the influence of the background noise can be reduced.
  • each image obtained through image reconstruction is normalized.
  • the pixel value is normalized from the maximum and minimum intervals to a zero-to-one interval. Because each image is normalized to an equal maximum value, it is equivalent to enhancing the weak source image.
  • step S104 the normalized images are superimposed to form a composite image.
  • different color channels may be used for image superposition, so as to clearly present the distribution of each radioactive substance.
  • the data of each monitoring energy zone is analyzed separately, then other information outside the energy zone is excluded, and only the background events in the energy zone constitute noise. This noise is much reduced relative to the overall background, so this method can effectively improve the signal-to-noise ratio.
  • another benefit of analyzing the data of each monitoring energy zone separately is that in the dynamic mode, when the movement of a certain radioactive material is detected in real time, only the radioactive material can be cleared. The projected image of the selected monitoring energy area of the material is used to refresh without clearing other monitoring energy areas. Therefore, in the case of using the same monitoring energy area, the imaging of moving matter and stationary matter does not affect each other.
  • Figure 4 shows a graphical representation of energy spectra captured by a gamma camera from three radioactive sources (Am241, Co57, Ba133).
  • the horizontal axis represents energy in units of channel value
  • the vertical axis represents count value
  • the light gray area provides valid information
  • the dark gray area provides noise information.
  • 4 monitoring energy regions are determined from the total energy spectrum, including two branches of Am241 (shown as spectral peaks in the figure, called successively as The first spectral peak and the second spectral peak), a branch of Co57 (called the third spectral peak), and a branch of Ba133 (called the fourth spectral peak), which are the optimal signal-to-noise ratio regions.
  • imaging is performed separately.
  • the characteristic peak at 355 keV of Ba133 cannot be imaged because its optimal signal-to-noise ratio area does not meet the threshold requirement.
  • FIG. 5 illustrates an example composite image obtained by reconstructing the energy spectra of the three radioactive sources (Am241, Co57, Ba133) in FIG. 4 by using the method of the embodiment of the present application by a gamma camera.
  • the first and second spectral peaks are reconstructed to obtain an image of Am241
  • the third spectral peak is reconstructed to obtain an image of Ba133
  • the fourth spectral peak is reconstructed to obtain an image of Co57, where the imaging position is indicated by an arrow in the picture .
  • the imaging map (as shown in Figure 5) obtained according to the gamma camera imaging method of the embodiment of the present application contains more information about radioactive substances . Because the detection efficiency and energy resolution of the gamma camera are not high, the probability of weak peaks and heavy peaks is relatively high, and the conventional peak-finding method based on the shape of the curve cannot find peaks well, so this method uses a peak-finding method similar to the nuclide library. traversal method. Because there are not many types of radioactive substances that can be detected by gamma cameras, even if traversal calculations are performed on all detectable radioactive substances, the amount of calculation and the speed of real-time processing are within an acceptable range.
  • the method in the embodiment of the present application mainly displays the type and distribution of radioactive substances within the field of view of the gamma camera.
  • the existence and location information of radioactive substances are more important, while the relative strength is less important. If you need to check the strength and weakness information of radioactive substances, you can display them in the normal display mode.
  • FIG. 7 shows an image obtained by reconstructing images of two radioactive sources (Am241, Co57) using a conventional method with a gamma camera and an image obtained by reconstructing images of the same radioactive source using the method of the embodiment of the present application comparison diagram.
  • Figure 7 includes Figure 7(a) on the left and Figure 7(b) on the right, wherein Figure 7(a) is a gamma image obtained using conventional methods, and Figure 7(b) is obtained using the method of the embodiment of the present application gamma image.
  • Figure 7(a) is a gamma image obtained using conventional methods
  • Figure 7(b) is obtained using the method of the embodiment of the present application gamma image.
  • Within the field of view of the radiation field measured by the gamma camera there are two radioactive point sources of Am241 and Co57.
  • each reconstructed image can be synthesized with different color channels so that the obtained gamma image is a color image.
  • Am241 can be represented in cyan
  • Co57 can be displayed in red.
  • Each color channel can be different from the example and be set according to requirements.
  • FIG. 8 illustrates a block diagram of a gamma camera imaging device according to an embodiment of the present application.
  • a gamma camera imaging device 800 according to an embodiment of the present application includes a selection module 801 , an image reconstruction module 802 , a normalization module 803 , and a superposition module 804 .
  • the selection module 801 selects one or more energy ranges of each radioactive substance from the energy spectrum of one or more radioactive substances captured by the gamma camera as one or more monitoring energy regions of the radioactive substance;
  • the image reconstruction module 802 performs image reconstruction on the monitoring energy range of each radioactive substance in the one or more radioactive substances;
  • the normalization module 803 normalizes each image obtained through the image reconstruction; and an overlay module, overlaying the normalized images to form a composite image.
  • the selection module 801 includes: a peak-finding module 8011, which performs traversal peak-finding from the energy spectrum, and compares the peak-finding results with the energy of each branch of the radioactive material recorded in the predetermined nuclide library to determine the One or more radioactive substances; the branch determination module 8012, the branch determination module, for each radioactive substance in the one or more radioactive substances, the branch of the branch of the radioactive substance is relatively higher or the branch with lower energy Determine one or more branches to be monitored as the radioactive substance; and the energy zone determination module 8013, for each branch in the one or more branches of each radioactive substance, use the center energy of the branch The energy range centered on the half-maximum width of the corresponding spectral peak of the branch is determined as one of the one or more monitoring energy regions of the radioactive substance.
  • a peak-finding module 8011 which performs traversal peak-finding from the energy spectrum, and compares the peak-finding results with the energy of each branch of the radioactive material recorded in the predetermined nucli
  • the image reconstruction module 802 includes: a closed area determination module 8021, for each image obtained through the image reconstruction, determine whether there is a closed area in each image; and an energy zone adjustment module 8022, in the image In the case of a closed area, if the contrast ratio of the closed area to the background area outside the closed area is smaller than a predetermined threshold, the energy range of the monitoring energy area corresponding to the image is adaptively adjusted.
  • the energy region adjustment module 8022 is configured to: gradually try to expand or reduce the monitored energy region to be adjusted with a predetermined energy step as a unit, until the closed region is in line with the background outside the closed region until the contrast of the region reaches the predetermined threshold.
  • the image reconstruction module 802 further includes a discarding module 8023 configured to discard the data of the monitored energy region corresponding to the image if there is no closed area in the image.
  • the discarding module 8023 is configured to discard the data of the monitored energy region corresponding to the image after a predetermined time if there is no closed area in the image.
  • the above-mentioned gamma camera imaging method and device according to the embodiments of the present application can be used in a gamma camera to obtain an enhanced gamma image, so as to be fused with an optical image to identify radioactive substances and their distribution information.
  • the gamma camera imaging method and device according to the embodiments of the present application can take all radioactive substances into account by analyzing each monitoring energy region of each radioactive substance separately, and reduce the background noise, thereby mentioning SNR.
  • the gamma camera imaging method and device according to the embodiments of the present application can only refresh the projection image of the moving radioactive material in the dynamic measurement mode, so that the imaging of the moving material and the stationary material do not affect each other.
  • the present application also provides a gamma camera imaging device, including: a memory storing instructions; a processor configured to execute the instructions stored in the memory to perform the above-mentioned gamma camera Imaging method.
  • the present application further provides a gamma camera, including the above gamma camera imaging device.
  • FIG. 9 illustrates an example block diagram of a computing device that may be used to implement a gamma camera imaging device according to an embodiment of the application.
  • computing device 900 may include one or more processors or processor cores 901 and memory 902 .
  • processors or processor cores 901 may include any type of processor, such as a central processing unit, a microprocessor, and the like.
  • Processor 901 may be implemented as an integrated circuit with multiple cores, eg, a multi-core microprocessor.
  • memory 902 may be system memory.
  • memory 902 may be integrated with processor 901 .
  • Computing device 900 may include mass storage device 903 (e.g., magnetic disk, hard drive, volatile memory (e.g., dynamic random-access memory (DRAM), compact disc read-only memory) memory, CD-ROM), digital versatile disk (digital versatile disk, DVD), etc.).
  • volatile memory e.g., dynamic random-access memory (DRAM), compact disc read-only memory) memory, CD-ROM), digital versatile disk (digital versatile disk, DVD), etc.
  • memory 902 and/or mass storage device 903 can be any type of temporary and/or persistent storage , including but not limited to volatile and non-volatile memory, optical, magnetic and/or solid-state mass storage, etc.
  • Volatile memory may include but not limited to static and/or dynamic random access memory.
  • Non-volatile Non-volatile memory may include, but is not limited to, electrically erasable programmable read-only memory, phase change memory, resistive memory, and the like.
  • Computing device 900 may also include input/output (I/O) devices 904 (e.g., display (e.g., touch screen display), keyboard, cursor control, remote control, game controller, image capture device, etc.) and communication interface 905 (such as network interface cards, modems, infrared receivers, radio receivers (eg, Bluetooth), etc.).
  • I/O input/output
  • the communication interface 905 can communicate with other devices in a wired or wireless manner to exchange data. For example, through the communication interface 905, gamma imaging can be transmitted for fusion with optical imaging.
  • system bus 906 represents one or more buses. In the case of multiple buses, they may be bridged by one or more bus bridges (not shown). Each of these elements may perform its conventional function as known in the art.
  • memory 902 and mass storage device 903 may be employed to store working and permanent copies of programming instructions for the operation of the gamma camera imaging device.
  • the various elements may be implemented by assembly instructions supported by processor(s) 901 or a high-level language that may be compiled into such instructions.
  • a permanent copy of the programming instructions can be placed in mass storage device 903 at the factory, or in the field via, for example, a distribution medium (not shown) such as a compact disk (CD), or via communication interface 905 (from a distribution server (not shown) Shown)) to distribute. Therefore, in some embodiments, the present application provides a computer-readable storage medium storing instructions, which when executed by a processor cause the processor to execute the above gamma camera imaging method.
  • computing device 900 may include a laptop, netbook, notebook, ultrabook, smartphone, tablet device, personal digital assistant (PDA), ultra-mobile PC, mobile phone, or digital One or more components of a camera.
  • computing device 900 may be any other electronic device that processes data.

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Abstract

本公开提供伽马相机成像方法和装置。该方法包括：从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；针对这一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建；对通过图像重建而得到的各个图像进行归一化；以及将经归一化后的各个图像进行叠加以形成合成图像。

Description

伽马相机成像方法和装置
相关申请的交叉引用
本申请要求享有于2021年12月28日提交的名称为“伽马相机成像方法和装置”的中国专利申请202111627470.7的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本发明涉及伽马相机的技术领域，尤其涉及伽马相机成像方法和装置。
背景技术
伽马相机应用于核安全和核检测领域，主要功能是对放射性物质沾染区域的辐射场进行动态和静态成像，并与光学成像图像进行融合，得到放射性物质分布信息。
现有伽马相机通常采用线性数据处理方法，即对接收到的信号不做区分，对所有有效能量段的信号一起进行投影图像恢复和原始图像重建。因为数据处理过程中有量化损失和近似处理，重建图像后，亮斑的背景里经常有统计波动和阴影。之后使用亮度阈值或显著度阈值等对图像区域进行筛选，只选取部分比较明显的成像图像与光学图像进行融合。
发明内容
根据本申请的一方面，提供了一种伽马相机成像方法，该方法包括：从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；针对所述一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建；对通过所述图像重建而得到的各个图像进行归一化；以及将经归一 化后的各个图像进行叠加以形成合成图像。
在一些实施例中，所述选择包括：从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
在一些实施例中，所述伽马相机成像方法还包括：针对通过所述图像重建而得到的各个图像，确定每一个所述图像中是否有封闭区域；在所述图像中存在封闭区域的情况下，如果所述封闭区域与所述封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。
在一些实施例中，所述自适应地调整包括：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。
在一些实施例中，所述伽马相机成像方法还包括：在所述图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。
在一些实施例中，所述伽马相机成像方法还包括：在所述图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。
根据本申请的另一方面，提供一种伽马相机成像装置，包括：选择模块，从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；图像重建模块，针对所述一种或多中放射性物质中每一种放射性物质的监测能区分别进行图像重建；归一化模块，对通过所述图像重建而得到的各个图像进行归一化；以及叠加模块，将经归一化后的各个图像进行叠加以形成合成图像。
在一些实施例中，选择模块包括：寻峰模块，从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；分支确定模块，针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及能区确定模块，针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
在一些实施例中，图像重建模块还包括：封闭区域确定模块，针对通过所述图像重建而得到的各个图像，确定每一个所述图像中是否有封闭区域；以及能区调整模块，在所述图像中存在封闭区域的情况下，如果所述封闭区域与所述封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。
在一些实施例中，能区调整模块被配置为：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。
在一些实施例中，图像重建模块还包括舍弃模块，该舍弃模块被配置为在所述图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。在一些实施例中，该舍弃模块被配置为在所述图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。
根据本申请的另一方面，提供一种伽马相机成像装置，包括：存储器，存储有指令；处理器，被配置为执行所述存储器中存储的所述指令以执行根据上述的伽马相机成像方法。
根据本申请的另一方面，提供一种计算机可读存储介质，存储有指令，所述指令在被处理器执行时使得所述处理器执行上述的伽马相机成像方法。
根据本申请的又一方面，提供一种伽马相机，包括上述任一种伽马相机成像装置。
根据本申请的实施例的伽马相机成像方法和装置通过对每种放射性物质的每个监测能区进行单独分析，能够将所有的放射性物质考虑在内，并降低了本底噪声，从而提高了信噪比。此外，根据本申请的实施例的伽马相机成像方法和装置还能在动态测量模式下仅刷新运动的放射性物质的投影图像，使得运动物质和静止物质的成像互不影响。
附图说明
通过参考附图会更加清楚地理解本发明的特征和优点，附图是示意性的而不应理解为对本发明进行任何限制，在附图中：
图1示出伽马相机从三个放射性源(Am241，Co57，Ba133)捕获的能谱的图示；
图2示出伽马相机使用常规方法对图1的三个放射性源(Am241，Co57，Ba133)的能谱进行图像重建得到的示例图像。
图3图示出根据本申请的实施例的伽马相机成像方法的流程图；
图4示出伽马相机从三个放射性源(Am241，Co57，Ba133)捕获的能谱的图示；
图5图示出伽马相机使用本申请实施例的方法对图4的三个放射性源(Am241，Co57，Ba133)的能谱进行图像重建得到的示例合成图像；
图6图示出伽马相机从高能量放射性物质(例如Co60)捕获的能谱的图示；
图7示出伽马相机使用常规方法对两个放射性源(Am241，Co57)进行图像重建得到的图像和使用本申请实施例的方法对同样的放射性源进行图像重建得到的图像的对比示意图。
图8图示出根据本申请的实施例的伽马相机成像装置的框图；以及
图9图示出可用于实现根据本申请的实施例的伽马相机成像装置的计算装置的示例框图。
具体实施方式
下面将详细描述本申请的各个方面的特征和示例性实施例。为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及具体实施例，对本申请进行进一步详细描述。应理解，此处所描述的具体实施例仅意在解释本申请，而不是限定本申请。对于本领域技术人员来说，本申请可以在不需要这些具体细节中的一些细节的情况下实施。下面对实施例的描述仅仅是为了通过示出本申请的示例来提供对本申请更好的理解。
伽马相机监测结果的呈现方式是图像，通过人眼观察屏幕上的图像来判断放射性物质的分布和种类，因此放射性物质能否成像是影响伽马相机监测结果的关键。而成像的基本条件是统计学角度观测到辐射源发出的伽马事件个数超过环境本底伽马事件的一定比例，即信噪比达到一定阈值后，才能通过统计和图像处理方法得到比较理想的分析结果。
在实际使用场合，要达到指定信噪比有一定难度。原因是由于探测器的尺寸材料等限制，高能量粒子的探测效率不高。而对于低能量粒子，环境中又存在相当数量的环境本底噪声。因此传统伽马相机探测距离通常不太远而且需要测量时间比较长。
图1示出伽马相机从三个放射性源(Am241，Co57，Ba133)捕获的能谱的图示。图1中包括图1(a)和图1(b)，其中横轴表示能量，以道值为单位，纵轴表示计数值。在图1(a)，以实线框标记出Am241所产生的能谱区域，以点划线框标记出Co57所产生的能谱区域，以虚线框标记出Ba133所产生的能谱区域。在图1(b)中，浅灰色区域提供有效信息，而深灰色区域提供噪声信息(在该示例中，只使用全能峰而不用康普顿散射坪数据作为有效信息来成像)。对于伽马相机的数据处理来说，当浅灰色区域的面积与深灰色区域的面积相比达到一定比率时，才能保证伽马相机比较好的成像。
在能成像的前提下，如果多种放射性物质的强弱差距较大，重建图像中的各个放射性点源形成的亮斑的亮度也差异很大。弱源的亮斑容易淹没在强源形成的统计波动背景里，由于亮度值难以超过筛选阈值，所以不会被选取以用于与光学图像融合，或者即使能被选取以用于与光学图像融 合，其亮度也非常弱，很难肉眼观察到。
图2示出伽马相机使用常规方法对图1的三个放射性源(Am241，Co57，Ba133)的能谱进行图像重建得到的示例图像。该图像中横纵坐标是伽马相机成像图像的像素刻度。在该图像中，只能观察到能谱中Am241的两个谱峰代表的亮斑，而无法观测到Co57和Ba133。因此，常规方法未能对来自所有放射源的信息进行充分展现。
根据本申请的实施例提供了一种伽马相机成像方法和装置，其能够充分利用各放射性源的有效信息，最优化显示视野里的放射性物质分布情况。
图3图示出根据本申请的实施例的伽马相机成像方法的流程图。如图3所示，根据本申请的实施例的伽马相机成像方法100包括：S101-S104。
在步骤S101，从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区。
对于步骤S01，在一些实施例中，对监测能区的选择可以包括：从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
应理解，针对一种放射性物质可选择一个监测能区，也可以选择多个监测能区，针对不同放射性物质所选择的监测能区也可能有重叠。此外，关于每一种放射性物质的分支的确定，主要考虑了两个标准，即分支比和能量，因为伽马相机的探测器对高能量伽马粒子的探测效率很低，尽量选择能量较低的分支；因为分支比越高，等量放射性物质产生的伽马粒子个数越多，所以尽量选择分支比较高的分支。应理解，在此所使用的术语“较低”和“较高”是放射性物质的各分支相比较而言的。
在步骤S102，针对所述一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建。
对于步骤S102，图像重建可根据需要选择常用的相关解码方法或统计学解码方法。
在一些实施例中，根据本申请的伽马相机成像方法还包括：针对通过图像重建而得到的各个图像，确定每一个图像中是否有封闭区域；在图像中存在封闭区域的情况下，如果封闭区域与封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。在一些实施例中，自适应地调整可以包括：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。自适应调整的能量范围由探测器的分辨率和相邻峰的距离决定，一般而言，如果伽马相机的能量标定比较准确，自适应调整的程度并不大,例如，一般可选择2～5个半高宽范围。
伽马相机可工作在静态测量模式下和动态测量模式下。在静态测量模式下，根据本申请的方法还可以包括：在图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。替代地，在动态测量模式下，根据本申请的方法还可以包括：在图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。由于在动态测量模式中，放射性物质的动态运动可能使得图像重建所得图像中出现封闭区域，因此，在持续观测预定时间后仍无封闭区域才进行数据舍弃。通过舍弃不能成像的监测能区数据，不但可以减小计算量，而且还可以减少本底噪声影响。
在步骤S103，对通过图像重建而得到的各个图像进行归一化。对于步骤S103，在归一化中，将像素值从最大最小值区间归一化到零到一区间。因为各个图像都归一化到了相等的最大值，相当于对弱源图像做了增强。
在步骤S104，将经归一化后的各个图像进行叠加以形成合成图像。对于步骤S104，图像叠加可以采用不同颜色通道，以清楚地呈现出各放射性物质的分布。
根据本申请的实施例的伽马相机成像方法，对每个监测能区的数据单独进行分析，则在该能区外的其他信息都被排除，只有该能区内的本底事件构成噪声，此噪声相对于整体本底来说减少了很多，因此该方法能够有效地提高信噪比。此外，根据本申请的实施例的伽马相机成像方法对每个监测能区的数据单独进行分析的另一个好处是，动态模式下，实时检测到某放射性物质的运动时，可以只清除该放射性物质的所选监测能区的投影图像来进行刷新，而不清除其他监测能区，因此在使用相同监测能区的情况下，运动物质和静止物质的成像互不影响。
图4示出伽马相机从三个放射性源(Am241，Co57，Ba133)捕获的能谱的图示。在图4中，横轴表示能量，以道值为单位，纵轴表示计数值，并且浅灰色区域提供有效信息，而深灰色区域提供噪声信息。如图4所示，根据本申请实施例的伽马相机成像方法从总能谱中确定出4个监测能区，包括了Am241的两个分支(在图中以谱峰示出，依次称为第一谱峰和第二谱峰)，Co57的一个分支(称为第三谱峰)，Ba133的一个分支(称为第四谱峰)，它们是最优信噪比区域。对于这四个监测能区，分别进行成像。Ba133的355kev处的特征峰，由于其最优信噪比区域也达不到阈值要求，而无法成像。
对这四个监测能区通过图像重建而得到的各个图像进行归一化，并将经归一化后的各个图像进行叠加以形成合成图像。图5图示出伽马相机使用本申请实施例的方法对图4的三个放射性源(Am241，Co57，Ba133)的能谱进行图像重建得到的示例合成图像。在图5中，第一谱峰和第二谱峰重建得到Am241的图像，第三谱峰重建得到Ba133的图像，第四谱峰重建得到Co57的图像，其中在图片中用箭头指示出成像位置。
与利用常规方法获得的成像图(如图2所示)相比，根据本申请实施例的伽马相机成像方法获得的成像图(如图5中所示)包含了更多有关放射性物质的信息。因为伽马相机的探测效率和能量分辨率不高，弱峰重峰出现概率较大，常规的基于曲线形状的寻峰方法不能很好地寻峰，所以本方法使用类似核素库寻峰的遍历方法。因为伽马相机可探测的放射性物质种类不多，即使对所有可探测的放射性物质都进行遍历计算，计算量和实 时处理的速度也在可接受范围内。有些特殊情况，如高能量的放射性物质(例如Co60)，因为提高了信噪比，仅累积几十个伽马事件即可成较好的像，反而能减少测量时间。例如，图6中Co60的能谱其最优成像能区在300～450道(如图中以框线示出)，虽然在能谱上完全观测不到峰形，根据本申请实施例的方法却可以得到很明显的重建图像。
本申请实施例的方法主要显示伽马相机视野内的放射性物质的种类和分布。对伽马相机的应用场景来说，放射性物质的存在性和位置信息更重要，而相对强弱的重要性较低，如果需要检查放射性物质强弱信息，可另行用普通显示模式再进行显示。
作为另一示例，图7示出伽马相机使用常规方法对两个放射性源(Am241，Co57)进行图像重建得到的图像和使用本申请实施例的方法对同样的放射性源进行图像重建得到的图像的对比示意图。图7包括左边的图7(a)和右边的图7(b)，其中图7(a)是利用常规方法获得的伽马图像，而图7(b)是利用本申请实施例的方法获得的伽马图像。在伽马相机测量的辐射场视野内，有Am241和Co57两个放射性点源。从左边的图像中只能看到中间偏左位置的Am241亮斑，因为Am241源的活度较大，背景整体很亮，所以遮蔽了Co57的亮斑。从右边的图像中可以看见两个点源(Am241，Co57)的成像(靠左为Am241，靠右为Co57)都比较明显。需注意，根据本申请实施例的方法可以对各重建图像以不同的颜色通道来进行合成使得所得的伽马图像是彩图，例如，Am241可以青色表示，Co57可以红色显示。各颜色通道可以与示例不同，根据需求来设置。
下面描述根据本申请的实施例的伽马相机成像装置。图8图示出根据本申请的实施例的伽马相机成像装置的框图。如图8所示，根据本申请的实施例的伽马相机成像装置800包括选择模块801、图像重建模块802、归一化模块803、和叠加模块804。具体地，选择模块801从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；图像重建模块802针对所述一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建；归一化模块803对通过所述图像重建而得到的各个图像进行归 一化；以及叠加模块，将经归一化后的各个图像进行叠加以形成合成图像。
在一些实施例中，选择模块801包括：寻峰模块8011，从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；分支确定模块8012，分支确定模块，针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及能区确定模块8013，针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
在一些实施例中，图像重建模块802包括：封闭区域确定模块8021，针对通过所述图像重建而得到的各个图像，确定每一个图像中是否有封闭区域；以及能区调整模块8022，在图像中存在封闭区域的情况下，如果封闭区域与封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。
在一些实施例中，能区调整模块8022被配置为：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。
在一些实施例中，图像重建模块802还包括舍弃模块8023，该舍弃模块8023被配置为在图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。在一些实施例中，舍弃模块8023被配置为：在图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。
上述根据本申请的实施例的伽马相机成像方法和装置可用于伽马相机中以获得增强的伽马图像，从而用于与光学图像融合来识别放射性物质及其分布信息。根据本申请的实施例的伽马相机成像方法和装置通过对每种放射性物质的每个监测能区进行单独分析，能够将所有的放射性物质考虑在内，并降低了本底噪声，从而提到了信噪比。此外，根据本申请的实施 例的伽马相机成像方法和装置还能在动态测量模式下仅刷新运动的放射性物质的投影图像，使得运动物质和静止物质的成像互不影响。
在一些实施例中，本申请还提供一种伽马相机成像装置，包括：存储器，存储有指令；处理器，被配置为执行所述存储器中存储的所述指令以执行根据上述的伽马相机成像方法。
在一些实施例中，本申请还提供一种伽马相机，包括上述的伽马相机成像装置。
图9图示出可用于实现根据本申请的实施例的伽马相机成像装置的计算装置的示例框图。如图所示，计算装置900可包括一个或多个处理器或处理器核心901和存储器902。对于本申请(包括权利要求书)而言，术语“处理器”和“处理器核心”可被视为同义词，除非上下文明确地另有要求。处理器901可包括任何类型的处理器，例如中央处理单元、微处理器，等等。处理器901可被实现为具有多核心的集成电路，例如，多核心微处理器。在实施例中，存储器902可以是系统存储器。在一些实施例中，存储器902可与处理器901集成。计算装置900可包括大容量存储装置903(例如，磁盘、硬盘驱动器、易失性存储器(例如，动态随机访问存储器(dynamic random-access memory，DRAM)、致密盘只读存储器(compact disc read-only memory，CD-ROM)、数字多功能盘(digital versatile disk，DVD)，等等)。一般而言，存储器902和/或大容量存储装置903可以是任何类型的临时性和/或持久性存储，包括但不限于易失性和非易失性存储器、光学、磁性和/或固态大容量存储，等等。易失性存储器可包括但不限于静态和/或动态随机访问存储器。非易失性存储器可包括但不限于电可擦除可编程只读存储器、相变存储器、电阻式存储器，等等。
计算装置900还可包括输入/输出(I/O)装置904(例如，显示器(例如，触摸屏显示器)、键盘、光标控制、遥控器、游戏控制器、图像捕捉装置，等等)和通信接口905(例如网络接口卡、调制解调器、红外接收器、无线电接收器(例如，蓝牙)，等等)。通信接口905可以以有线或无线地方式与其他设备进行通信以交换数据。例如，通过该通信接口 905，伽马成像可被传输以与光学成像融合。
上述计算装置900的元素可经由系统总线906相互耦合，系统总线906表示一个或多个总线。在多个总线的情况下，它们可由一个或多个总线桥(未示出)来桥接。这些元素的每一者可执行本领域中已知的其传统功能。具体地，可以采用存储器902和大容量存储装置903来存储用于伽马相机成像装置的操作的编程指令的工作拷贝和永久拷贝。各种元素可由(一个或多个)处理器901所支持的汇编指令或者可被编译成这种指令的高级别语言来实现。编程指令的永久拷贝可在工厂被放入大容量存储装置903中，或者在现场通过例如分发介质(未示出)(比如致密盘(CD))，或者通过通信接口905(从分发服务器(未示出))来分发。因此，在一些实施例中，本申请提供一种计算机可读存储介质，存储有指令，所述指令在被处理器执行时使得所述处理器执行上述的伽马相机成像方法。
各元件的数目、能力和/或容量可以有变化，这取决于计算装置900是被用作固定的计算装置，还是被用作移动计算装置。在各种实现方式中，计算装置900可包括膝上型电脑、上网本、笔记本、超极本、智能电话、平板设备、个人数字助理(personal digital assistant，PDA)、超移动PC、移动电话或者数码相机的一个或多个组件。在另外的实现方式中，计算装置900可以是任何其他处理数据的电子装置。
以上对本发明的实施例的详细描述涵盖了许多具体细节，以便提供对本发明的全面理解。但是，对于本领域技术人员来说显而易见的是，本发明可以在不需要这些具体细节中的一些细节的情况下实施。上面对实施例的描述仅仅是为了通过示出本发明的示例来提供对本发明更清楚的理解。本发明绝不限于下面所提出的任何具体配置和方法步骤，而是在不脱离本发明的教导的前提下覆盖了相关元素、部件和方法步骤的任何修改、替换和改进。
应当注意，在权利要求中，单词“包含”或“包括”并不排除存在未列在权利要求中的元件或组件。位于元件或组件之前的冠词“一”或“一个”也并不排除存在多个这样的元件或组件的情况。
此外，还应当注意，本说明书中使用的语言主要是为了可读性和教导的目的而选择的，而不是为了解释或者限定本发明的主题而选择的。因此，在不偏离所附权利要求书的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。关于本发明的范围，说明书中所做的描述都是说明性的，而非限制性的，本发明的范围由所附权利要求书限定。

Claims (16)

  1. 一种伽马相机成像方法，包括：
    从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；
    针对所述一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建；
    对通过所述图像重建而得到的各个图像进行归一化；以及
    将经归一化后的各个图像进行叠加以形成合成图像。
  2. 根据权利要求1所述的伽马相机成像方法，其中，所述选择包括：
    从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；
    针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及
    针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
  3. 根据权利要求1所述的伽马相机成像方法，还包括：
    针对通过所述图像重建而得到的各个图像，确定每一个所述图像中是否有封闭区域；
    在所述图像中存在封闭区域的情况下，如果所述封闭区域与所述封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。
  4. 根据权利要求3所述的伽马相机成像方法，其中，所述自适应地调整包括：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。
  5. 根据权利要求3所述的伽马相机成像方法，还包括：
    在所述图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。
  6. 根据权利要求3所述的伽马相机成像方法，还包括：
    在所述图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。
  7. 根据权利要求1所述的伽马相机成像方法，其中，所述叠加包括：将经归一化后的各个图像以不同的颜色通道进行叠加以形成所述合成图像。
  8. 一种伽马相机成像装置，包括：
    选择模块，从伽马相机所捕获的一种或多种放射性物质的能谱中选择每一种放射性物质的一个或多个能量范围作为该放射性物质的一个或多个监测能区；
    图像重建模块，针对所述一种或多种放射性物质中每一种放射性物质的监测能区分别进行图像重建；
    归一化模块，对通过所述图像重建而得到的各个图像进行归一化；以及
    叠加模块，将经归一化后的各个图像进行叠加以形成合成图像。
  9. 根据权利要求8所述的伽马相机成像装置，其中，所述选择模块包括：
    寻峰模块，从所述能谱中进行遍历寻峰，将寻峰结果与预定核素库记载的放射性物质各分支能量进行对比，以确定所述一种或多种放射性物质；
    分支确定模块，针对所述一种或多种放射性物质中每一种放射性物质，将该放射性物质的分支中分支比较高或能量较低的分支确定为该放射性物质的要进行监测的一个或多个分支；以及
    能区确定模块，针对每一种放射性物质的所述一个或多个分支中的每一个分支，将以该分支的中心能量为中心并以该分支对应谱峰的半高宽为宽度的能量范围确定为该放射性物质的一个或多个监测能区之一。
  10. 根据权利要求8所述的伽马相机成像装置，其中，所述图像重建 模块包括：
    封闭区域确定模块，针对通过所述图像重建而得到的各个图像，确定每一个所述图像中是否有封闭区域；以及
    能区调整模块，在所述图像中存在封闭区域的情况下，如果所述封闭区域与所述封闭区域以外的背景区域的对比度之比小于预定阈值，则自适应地调整与该图像相应的监测能区的能量范围。
  11. 根据权利要求10述的伽马相机成像装置，其中，所述能区调整模块被配置为：对待调整的监测能区，以预定能量步长为单位进行逐步尝试扩增或减少，直到所述封闭区域与所述封闭区域以外的背景区域的对比度达到所述预定阈值为止。
  12. 根据权利要求10所述的伽马相机成像装置，其中，所述图像重建模块还包括舍弃模块，所述舍弃模块被配置为在所述图像中不存在封闭区域的情况下，将与该图像相应的监测能区的数据舍弃。
  13. 根据权利要求10所述的伽马相机成像装置，其中，所述图像重建模块还包括舍弃模块，所述舍弃模块被配置为在所述图像中不存在封闭区域的情况下，在预定时间后，将与该图像相应的监测能区的数据舍弃。
  14. 一种伽马相机成像装置，包括：
    存储器，存储有指令；
    处理器，被配置为执行所述存储器中存储的所述指令以执行根据权利要求1-7中任一项所述的方法。
  15. 一种计算机可读存储介质，存储有指令，所述指令在被处理器执行时使得所述处理器执行根据权利要求1-7中任一项所述的方法。
  16. 一种伽马相机，包括如权利要求8-14中任一项所述的伽马相机成像装置。
PCT/CN2022/127110 2021-12-28 2022-10-24 伽马相机成像方法和装置 Ceased WO2023124459A1 (zh)

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