Gamma camera imaging method and gamma camera imaging device

Abstract

Gamma camera imaging techniques, which include: Select (S101) from energy spectra recorded by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material, as one or more monitored energy ranges of the radioactive material; Performing (S102) an image reconstruction on the monitored energy ranges of each radioactive material among the one or more radioactive materials; Performing (S103) a normalization of the images obtained by image reconstruction; and Performing (S104) a superposition on the normalized images to produce a composite image, characterized by the fact that the selection includes: Sweeping through the energy spectra to find peaks and comparing the peaks with energies of branches of respective radioactive materials recorded in a predetermined nuclide bank to determine the one or more radioactive materials; Determine, for each radioactive material among the one or more radioactive materials, a portion of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material to be monitored; and Determine, for each branch of the one or more branches, an energy range of the radioactive material centered on a central energy of the branch and having a width of half a height width of a peak corresponding to the branch as one of the one or more monitored energy ranges of the radioactive material.

Description

TECHNICAL AREA

[0001] The present application relates to the technical field of gamma cameras, in particular to a gamma camera imaging method and a gamma camera imaging device. BACKGROUND

[0002] A gamma camera is primarily used in the field of nuclear safety and testing to create a dynamic or static image of a radiation field of a contamination area with radioactive material, and the resulting image is used in combination with an image from an optical imaging procedure to obtain information about a distribution of the radioactive material.

[0003] An existing gamma camera generally uses a linear data processing method that makes no distinction between the received signals and reconstructs the projected image and the original image using all effective energy bands of the signals. After image reconstruction, statistical fluctuations and shadows often appear in the background of the bright spots due to quantization losses and approximation processes during data processing. A screening procedure is then applied to image areas using a brightness threshold or a significance threshold to select only those image areas with more conspicuous images for use in combination with optical images.

[0004] CN 110599562 addresses a reconstruction method for positioning a radioactive source based on a multi-energy system response matrix. The method comprises: dividing an energy range detectable by a coded aperture imaging system into multiple energy windows; selecting a characteristic energy value for each energy window; determining a system response matrix for each energy window based on the characteristic energy value by simulation; during an actual measurement, determining energy window counts according to the measured data to form multiple sets of projection data corresponding to the energy windows; subsequently applying a maximum likelihood expectation maximization algorithm to reconstruct images of the energy windows; and summing the reconstructed images to obtain a final reconstructed image.

[0005] WO 02 / 101416 A relates to a nuclear camera system in which the energy spectrum peaks identified by a camera detector head are automatically adjusted to account for drift and other sources of inaccuracy. SUMMARY

[0006] According to one aspect of the present application, a gamma camera imaging method is provided which comprises: selecting one or more energy ranges of each radioactive material from the one or more radioactive materials from energy spectra acquired by a gamma camera on one or more radioactive materials, as one or more monitored energy ranges of the radioactive material; performing image reconstruction on the monitored energy ranges of each radioactive material from the one or more radioactive materials; performing normalization on images obtained by the image reconstruction;and performing a superposition on the normalized images to form a composite image, wherein the selection includes: traversing the energy spectra to find peaks and comparing the peaks with energies of branches of corresponding radioactive materials recorded in a predetermined nuclide bank to identify the one or more radioactive materials; determining, for each radioactive material among the one or more radioactive materials, a portion of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material to be monitored;and determine, for each branch under the one or more branches of the radioactive material, an energy range centered on a central energy of the branch and having a width of half a peak width corresponding to the branch as one of the one or more monitored energy ranges of the radioactive materials.

[0007] In some embodiments, the gamma camera imaging method further comprises: determining, for each of the images obtained by image reconstruction, whether there is a closed area in the image; and adaptively adjusting, in a case where a closed area is present in the image, and if a ratio of the contrast of the closed area with respect to the contrast of a background area outside the closed area is less than a predetermined threshold, the energy ranges of the monitored energy ranges corresponding to the image.

[0008] In some embodiments, adaptive adjustment includes: gradually increasing or decreasing an energy range to be adjusted in a predetermined energy step until the ratio of the contrast of the closed area to the contrast of a background area outside the closed area reaches the predetermined threshold.

[0009] In some embodiments, the gamma camera imaging method further includes: discarding the energy ranges of the monitored energy ranges that correspond to the image if no closed area is present in the image.

[0010] In some embodiments, the gamma camera imaging method further includes: discarding the energy ranges of the monitored energy ranges that correspond to the image after a predetermined period of time if no closed area is present in the image.

[0011] According to another aspect of the present application, a gamma camera imaging device is provided, comprising: a selection module configured to select, from energy spectra acquired by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material from the one or more radioactive materials as one or more monitored energy ranges of the radioactive material; an image reconstruction module configured to perform image reconstruction on the monitored energy ranges of each radioactive material from the one or more radioactive materials; a normalization module configured to perform normalization on images obtained by the image reconstruction;and a superposition module configured to perform a superposition on the normalized images to form a composite image, the selection module comprising: a peak detection module configured to traverse the energy spectra to find peaks and compare the peaks with energies of branches of respective radioactive materials recorded in a predetermined nuclide bank to identify the one or more radioactive materials; a branch identification module configured to identify, for each radioactive material among the one or more radioactive materials, a portion of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material being monitored;and an energy range determination module configured to determine, for each branch under the one or more branches of the radioactive material, an energy range centered on a central energy of the branch and having a width of one half-height of a peak corresponding to the branch as one of the one or more monitored energy ranges of the radioactive materials.

[0012] In some embodiments, the image reconstruction module includes: a closed-area determination module configured to determine, for each image obtained by image reconstruction, whether a closed area is present in the image; and an energy range adjustment module configured to adaptively adjust the energy ranges of the monitored energy ranges according to the image in a case where a closed area is present in the image and the ratio of the contrast of the closed area to the contrast of a background area outside the closed area is less than a predetermined threshold.

[0013] In some embodiments, the energy range determination module is further configured to gradually increase or decrease an energy range to be set in a predetermined energy step until the ratio of the contrast of the closed range to the contrast of a background range outside the closed range reaches the predetermined threshold.

[0014] In some embodiments, the image reconstruction module further comprises: a rejection module configured to reject the energy ranges of the monitored energy ranges corresponding to the image in cases where no closed region is present in the image. In some embodiments, the image reconstruction module further comprises: a rejection module configured to reject the energy ranges of the monitored energy ranges corresponding to the image after a predetermined time interval in cases where no closed region is present in the image.

[0015] According to another aspect of the present application, a gamma camera imaging device is provided comprising: a memory that stores instructions; a processor configured to execute the instructions stored in the memory in order to perform the gamma camera imaging procedure described above.

[0016] According to another aspect of the present application, a computer-readable storage medium is provided on which instructions are stored that can be executed by a processor to perform the gamma camera imaging method described above.

[0017] According to another aspect of the present application, a gamma camera is provided which includes the gamma camera imaging device described above.

[0018] According to the gamma camera imaging method and gamma camera imaging device in the present application, each monitored energy range of each radioactive material is analyzed separately, thereby enabling the consideration of all radioactive materials, reducing background noise, and improving the signal-to-noise ratio. Furthermore, according to the gamma camera imaging method and gamma camera imaging device in the present application, only the projected images of moving radioactive materials need to be updated in a dynamic measurement mode, so that the imaging of the moving materials and the imaging of the stationary materials do not interfere with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features and advantages of the present application will be more clearly understood by reference to the accompanying drawings. The drawings are schematic and should not be interpreted as limiting the present application. The drawings show: Fig. Figure 1 shows a diagram of an energy spectrum recorded by a gamma camera of three radioactive sources (Am241, Co57 and Ba133); Fig. Figure 2 shows a diagram of an example image obtained by image reconstruction using a gamma camera and a conventional method from the energy spectrum of the three radioactive sources (Am241, Co57 and Ba133) by Fig. 1 was won; Fig. Figure 3 shows a flowchart of a gamma camera imaging method according to an embodiment of the present application; Fig. Figure 4 shows a diagram of an energy spectrum recorded by a gamma camera of three radioactive sources (Am241, Co57 and Ba133); Fig. Figure 5 shows a diagram of a result image obtained by image reconstruction using a gamma camera and the gamma camera imaging method according to an embodiment of the present application from the three radioactive sources (Am241, Co57 and Ba133) of Fig. 4 was received; Fig. Figure 6 shows a diagram of an energy spectrum recorded by a gamma camera of a high-energy radioactive material (e.g. Co60); Fig. Figure 7 shows a comparison diagram of a result image obtained by image reconstruction using a gamma camera using a conventional method from two radioactive sources (Am241 and Co57) and a result image obtained by image reconstruction using a gamma camera using the gamma camera imaging method according to an embodiment of the present application from the same radioactive sources. Fig. Figure 8 shows a block diagram of a gamma camera imaging device according to an embodiment of the present application; and Fig. Figure 9 shows an exemplary block diagram of a computer device suitable for implementing a gamma camera imaging device according to an embodiment of the present application. DETAILED DESCRIPTION

[0020] A gamma camera's monitoring result is presented as an image from which the human eye can discern the type of radioactive substances and their distribution. Therefore, the ability to image the radioactive substances is a key factor influencing the gamma camera's monitoring result. A fundamental requirement for imaging is that the number of gamma events emitted by the radiation sources and statistically recorded exceeds the number of gamma events in the surrounding background by a certain ratio; that is, an ideal analysis result can only be achieved through statistical and image processing methods if the signal-to-noise ratio reaches a specific threshold.

[0021] In practical applications, achieving a specific signal-to-noise ratio is difficult. This is because the detection efficiency for high-energy particles is not high enough due to the limited size and material of the detectors, and because there is a considerable amount of background noise for low-energy particles. Therefore, a conventional gamma camera generally does not have a sufficiently large detection range and requires a relatively long measurement time.

[0022] Fig. Figure 1 shows a diagram of an energy spectrum recorded by a gamma camera of three radioactive sources (Am241, Co57 and Ba133). Fig. 1 is considered Fig. 1(a) and Fig. Figure 1(b) shows the energy in the form of a channel value and the vertical axis represents the count value. Fig. 1(a) is a region of the energy spectrum produced by Am241, marked with a solid line, a region of the energy spectrum produced by Co57 with a dotted line, and a region of the energy spectrum produced by Ba133 with a dashed line. In Fig. 1(b) A light gray area represents valid information, while a dark gray area provides noise information (in the example, full-energy peaks are used as valid information for imaging instead of flat Compton scattering data). When processing data for a gamma camera, the camera can only ensure better imaging if the ratio between the light gray area and the dark gray area reaches a certain level.

[0023] In imaging, the brightness of the bright spots formed by the respective radioactive point sources in the reconstructed image varies considerably when there is a large difference in the strength and weakness of the radioactive materials. A bright spot from a weaker radioactive source is easily lost in a statistically fluctuating background formed by a stronger radioactive source. Since the brightness value of the bright spot from the weaker radioactive source is unlikely to exceed a selection threshold, the bright spot from the weaker radioactive source is either not selected for combination with optical images, or even if it is, its brightness is very faint and difficult to detect with the human eye.

[0024] Fig. Figure 2 shows a diagram of an example image, which was reconstructed using a gamma camera and a conventional method from the energy spectrum of the three radioactive sources (Am241, Co57 and Ba133). Fig. 1 was won. Fig. Figure 2 represents the horizontal and vertical axes, respectively, as the pixel scales of a gamma camera image. This image shows only the bright spots represented by the two peaks of Am241 in the energy spectrum, but not Co57 and Ba133. Consequently, conventional methods cannot adequately represent the information from all radioactive sources.

[0025] According to the embodiment of the present application, a gamma camera imaging method and a gamma camera imaging device are provided which can fully utilize the effective information of each radioactive source, optimized display of radioactivity material distribution in the field of view.

[0026] Fig. Figure 3 shows a flowchart of a gamma camera imaging method according to an embodiment of the present application. As in Fig. As shown in Figure 3, the gamma camera imaging method 100 according to an embodiment of the present application comprises steps S101-S104.

[0027] In step S101, from the energy spectra recorded by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material from the one or more radioactive materials are selected as one or more monitored energy ranges of the radioactive material.

[0028] For step S101, the selection of the monitored energy ranges in some embodiments may include: traversing the energy spectra to find peaks and comparing the peaks with energies of branches of corresponding radioactive materials recorded in a predetermined nuclide bank to identify the one or more radioactive materials; determining, for each radioactive material among the one or more radioactive materials, a subset of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material to be monitored;and determine, for each branch under the one or more branches of the radioactive material, an energy range centered on a central energy of the branch and having a width of half a peak width corresponding to the branch as one of the one or more monitored energy ranges of the radioactive materials.

[0029] It should be understood that for a radioactive material, one or more monitored energy ranges can be selected, and for different radioactive materials, their monitored energy ranges may overlap. Furthermore, when determining the branches of each radioactive material, two main criteria are considered: a branch ratio and an energy. This is because gamma camera detectors are less efficient at detecting high-energy gamma particles, making it preferable to select a lower-energy branch. Conversely, the higher the branch ratio, the more gamma particles the same amount of radioactive material produces, making it preferable to select a branch with a higher branch ratio. The terms "lower" and "higher," as used here, refer to the different branches of the radioactive material.

[0030] In step S102, image reconstruction is performed for the monitored energy ranges of each radioactive material from the one or more radioactive materials.

[0031] In step S102, a common decoding method or a statistical decoding method can be used for image reconstruction, depending on requirements.

[0032] In some embodiments, the gamma camera imaging method according to the present application may further comprise: determining, for each of the images obtained by image reconstruction, whether a closed area is present in the image; and adaptively adjusting the energy ranges of the monitored energy ranges corresponding to the image, in a case where a closed area is present in the image, and if a ratio of the contrast of the closed area with respect to the contrast of a background area outside the closed area is less than a predetermined threshold.In some embodiments, the adaptive adjustment may involve gradually increasing or decreasing an energy range to be adjusted in a predetermined energy step until the ratio of the contrast of the closed region to the contrast of a background region outside the closed region reaches the predetermined threshold. The energy range to be adaptively adjusted is determined by the detector resolution and the distance between adjacent peaks. If the energy calibration of the gamma camera is relatively accurate, the degree of adaptive adjustment is generally not too large; for example, a range of 2 to 5 full widths of field (FWHM) can generally be selected.

[0033] The gamma camera can operate in a static measurement mode and in a dynamic measurement mode. In static measurement mode, the method according to the present application can further include: discarding the energy ranges of the monitored energy ranges that correspond to the image if there is no closed region in the image. Alternatively, in dynamic measurement mode, the method according to the present application can further include: discarding the energy ranges of the monitored energy ranges that correspond to the image after a predetermined time period if there is no closed region in the image. In dynamic measurement mode, the dynamic movement of the radioactive materials can cause a closed region to appear in the reconstructed image, so that the data are discarded after a predetermined period of continuous observation.By discarding data from a monitored energy range that cannot be mapped, not only can the computational effort be reduced, but also the influence of background noise.

[0034] In step S103, the images obtained through image reconstruction are normalized. During normalization, a pixel value is normalized from a maximum-minimum value interval to a zero-to-one interval. The images are normalized to the same maximum value, which improves an image from a weak source to an equivalent degree.

[0035] In step S104, the normalized images are superimposed to obtain a composite image. In step S104, different color channels can be used during image superimposition to clearly depict the distribution of the respective radioactive substances.

[0036] According to the gamma camera imaging method of an embodiment of the present application, the data of each monitored energy range are analyzed separately, and then other information outside the energy range is excluded, so that only background events within the energy range constitute noise, which is greatly reduced relative to the overall background. Thus, the method can effectively improve the signal-to-noise ratio. A further advantage of the gamma camera imaging method of the present application, in which the data of each monitored energy range are analyzed separately, is that if movement of a radioactive material is detected in real time in dynamic mode, only the projected image of the monitored energy range of the radioactive material can be released for updating, without affecting other monitored energy ranges.Therefore, in the same monitored energy ranges, the images of the moving material and the stationary material do not influence each other.

[0037] Fig. Figure 4 shows a diagram of an energy spectrum recorded by a gamma camera from three radioactive sources (Am241, Co57 and Ba133). Fig. Figure 4 shows that the horizontal axis represents the energy in the form of a channel value and the vertical axis the count value; a light gray area provides valid information, while a dark gray area provides noise information. As in Fig. As shown in Figure 4, the gamma camera imaging method according to the embodiment of the present application identifies four monitored energy ranges from a total energy spectrum, including two branches of Am241 (shown in the figure as the peaks of the spectrum, i.e., the first and second peaks), one branch of Co57 (referred to as the third peak), and one branch of Ba133 (referred to as the fourth peak), which are optimal signal-to-noise ratio ranges. Imaging is performed separately for these four monitored energy ranges. The characteristic peak at 355 keV of Ba133 cannot be used for imaging because its optimal signal-to-noise ratio range does not meet the threshold requirements.

[0038] The images obtained through image reconstruction of these four monitored energy ranges are normalized, and the normalized images are superimposed to form a composite image. Fig. Figure 5 shows a diagram of a result image obtained by image reconstruction with a gamma camera using the gamma camera imaging method according to an embodiment of the present application from the three radioactive sources (Am241, Co57 and Ba133) of Fig. 4 was received. In Fig. 5. The first and second tips are used for reconstruction to obtain an image of Am241, the third tip is used for reconstruction to obtain an image of Ba133, and the fourth tip is used for reconstruction to obtain an image of Co57, whose positions in the figure are indicated by arrows.

[0039] The image obtained using the gamma camera imaging method according to the embodiment of the present application (as in Fig. 5 shown) contains more information about the radioactive materials than the image obtained using the conventional method (as in Fig. (2 shown). Since the gamma camera lacks sufficient detection power and energy resolution, weaker peaks are more likely to overlap, making it difficult for a conventional peak-finding method based on the shape of the graph to accurately identify them. In contrast, the method presented here uses a traversal technique similar to peak finding in a radionuclide bank. Because there are not many types of radioactive materials that can be detected by the gamma camera, the computational effort and real-time processing speed remain within an acceptable range, even when scanning all detectable radioactive materials. In some special cases, such as with high-energy radioactive materials (like Co-60), the improved signal-to-noise ratio means that only a few dozen events need to be accumulated to obtain a better image, which can reduce the measurement time.The optimal energy range for imaging in the energy spectrum of Co60 in . Fig. For example, channel 6 lies between the 300th and 450th channels (shown as a box in the figure). Although no peak is visible in the energy spectrum, the method according to the present application can provide a very clear reconstruction image.

[0040] The method according to the embodiment of the present application mainly displays the types and distribution of radioactive materials in the field of view of a gamma camera. For application in the gamma camera, information about the presence and location of radioactive substances is more important than their relative strength. Therefore, if it is necessary to verify the information about the strength and weakness of the radioactive substances, a conventional display mode can be used for further display.

[0041] As another example, Fig. 7 a comparison diagram of a result image obtained by image reconstruction using a gamma camera using a conventional method from two radioactive sources (Am241 and Co57) and a result image obtained by image reconstruction using a gamma camera using the gamma camera imaging method according to an embodiment of the present application from the same radioactive sources. Fig. 7 is considered Fig. 7 (a) on the left side and Fig. 7 (b) shown on the right-hand side, wherein Fig. 7 (a) is a gamma image obtained by the conventional method, and Fig. 7 (b) is a gamma image obtained by the method according to the embodiment of the present application. Within the radiation field measured by the gamma camera are two radioactive point sources, namely Am241 and Co57. In the image on the left, only a bright spot of Am241 is visible in the middle of the left side, since the Am241 source has high activity and the background is very bright overall, so that it obscures a bright spot of Co57. In the image on the right, the images of the two point sources (Am241, Co57) are clearly visible (Am241 on the left, Co57 on the right). It should be noted that the method according to the embodiment of the present application can assign different color channels to the respective reconstructed image, so that the resulting gamma image is a color image. For example, Am241 can be displayed in cyan, Co57 in red. The assignment of the color channels can deviate from the example and be adjusted as required.

[0042] A gamma camera imaging device according to an embodiment of the present application is described below. Fig. Figure 8 shows a block diagram of a gamma camera imaging device according to an embodiment of the present application. As in Fig. As shown in Figure 8, the gamma camera imaging device 800 according to the embodiment of the present application comprises a selection module 801, an image reconstruction module 802, a normalization module 803, and a superposition module 804. In particular, the selection module 801 is configured to select, from energy spectra acquired by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material from the one or more radioactive materials as one or more monitored energy ranges of the radioactive material. The image reconstruction module 802 is configured to perform image reconstruction at the monitored energy ranges of each radioactive material from the one or more radioactive materials. The normalization module 803 is configured to perform normalization of the images obtained by the image reconstruction.The overlay module 804 is configured to perform an overlay of the normalized images to create a composite image.

[0043] In some embodiments, the selection module 801 may comprise: a peak detection module 8011 configured to analyze the energy spectra to locate peaks and compare the peaks with energies of branches of the respective radioactive materials recorded in a predetermined nuclide bank to identify the one or more radioactive materials; a branch identification module 8012 configured to identify, for each radioactive material among the one or more radioactive materials, a portion of the branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material to be monitored;and an energy range determination module 8013 configured to determine for each branch under the one or more branches of the radioactive material an energy range centered on a central energy of the branch and having a width of one half-height width of a peak corresponding to the branch as one of the one or more monitored energy ranges of the radioactive materials.

[0044] In some embodiments, the image reconstruction module 802 may comprise: a closed-area determination module 8021 configured to determine, for each of the images obtained by image reconstruction, whether a closed area is present in the image; and an energy range adjustment module 8022 configured to adaptively adjust the energy ranges of the monitored energy ranges according to the image in a case where a closed area is present in the image and the ratio of the contrast of the closed area to the contrast of a background area outside the closed area is less than a predetermined threshold.

[0045] In some embodiments, the energy range adjustment module 8022 can further be configured to: gradually increase or decrease an energy range to be set in a predetermined energy step until the ratio of the contrast of the closed range to the contrast of a background range outside the closed range reaches the predetermined threshold.

[0046] In some embodiments, the image reconstruction module 802 may further include a rejection module 8023 configured to reject the energy ranges of the monitored energy ranges corresponding to the image in cases where no closed region is present in the image. In some embodiments, the rejection module 8023 may further be configured to reject the energy ranges of the monitored energy ranges corresponding to the image after a predetermined time interval in cases where no closed region is present in the image.

[0047] The gamma camera imaging method and gamma camera imaging device described above, according to the embodiment of the present application, can be used in a gamma camera to obtain an enhanced gamma image, which, in combination with an optical image, is used to identify radioactive materials and their distribution information. According to the gamma camera imaging method and gamma camera imaging device in the present application, each monitored energy range of each radioactive material is analyzed separately, thereby enabling the consideration of all radioactive materials, reducing background noise, and improving the signal-to-noise ratio.Furthermore, according to the gamma camera imaging method and the gamma camera imaging device in the present application, only projected images of moving radioactive materials need to be refreshed in a dynamic measurement mode, so that the imaging of the moving materials and the imaging of the stationary materials do not affect each other.

[0048] In some embodiments, according to the present application, a gamma camera imaging device is further provided, comprising: a memory that stores instructions; a processor configured to execute the instructions stored in the memory in order to perform the gamma camera imaging method described above.

[0049] In some embodiments, a gamma camera is also provided according to the present application, which includes the gamma camera imaging device described above.

[0050] Fig.Figure 9 shows an exemplary block diagram of a computer device suitable for implementing a gamma camera imaging device according to an embodiment of the present application. As shown, the computer device 900 comprises one or more processors or processor cores 901 and a memory 902. In the present application (including the claims), the terms "processor" and "processor core" may be considered synonymous unless expressly stated otherwise. The processor 901 may be any type of processor, such as a central processing unit, a microprocessor, and the like. The processor 901 may be implemented as an integrated circuit with multiple cores, for example, as a multi-core microprocessor. In one embodiment, the memory 902 may be a system memory. In some embodiments, the memory 902 may be integrated with the processor 901.The computer device 900 may include a mass storage device 903 (e.g., a disk, a hard disk drive, volatile memory (e.g., dynamic random-access memory, DRAM), a compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), and the like). In general, the memory 902 and / or the mass storage device 903 may be any type of temporary and / or permanent memory, including, but not limited to, volatile and non-volatile memory, optical, magnetic, and / or solid-state memory, and the like. The volatile memory may include, but is not limited to, static and / or dynamic random-access memory. The non-volatile memory may include, among other things, electrically erasable programmable read-only memory, phase-change memory, resistive memory, and the like.

[0051] The computer device 900 may further include an input / output device (I / O device) 904 (e.g., a display (e.g., a touchscreen display), a keyboard, a cursor control, a remote control, a game controller, an image capture device, etc.) and a communication interface 905 (e.g., a network interface card, a modem, an infrared receiver, a radio receiver (e.g., Bluetooth), etc.). The communication interface 905 can communicate with other devices in a wired or wireless manner to exchange data. For example, gamma images can be transmitted via the communication interface 905 for use in combination with optical images.

[0052] The components of the computer device 900 can be interconnected via a system bus 906, which represents one or more buses. In the case of multiple buses, these can be bridged by one or more bus bridges (not shown). Each of these components can perform its traditional functions known in engineering. In particular, the memory 902 and the mass storage device 903 can be used to store a working copy and a persistent copy of the programming instructions for operating the gamma camera imaging device. The components can be implemented by assembly instructions supported by the processor(s) 901 or by any high-level language that can be compiled into such instructions. A persistent copy of the programming instructions can be stored at the factory in the mass storage device 903 or distributed locally, for example, via a distribution medium (not shown).a compact disk (CD) or via a communication interface 905 (from a distributor, not shown). Thus, in some embodiments according to the present application, a computer-readable storage medium is provided on which instructions are stored that can be executed by the processor to perform the gamma camera imaging method as described above.

[0053] The number, capability, and / or capacity of the components can vary depending on whether the Computer Device 900 is used as a stationary or mobile computing device. In various implementations, the Computer Device 900 may include one or more components of a laptop, netbook, notebook, ultrabook, smartphone, tablet, personal digital assistant (PDA), ultramobile PC, mobile phone, or digital camera. In another implementation, the Computer Device 900 may be any other electronic device capable of processing data.

[0054] The above detailed description of embodiments of the present application includes many specific details to provide a comprehensive understanding of the present application. However, it will be clear to a person skilled in the art that the present application can also be implemented without some of these specific details. The above description of embodiments merely serves to enhance the understanding of the present application by providing examples. The present application is by no means limited to the specific configurations and methodological steps proposed below, but includes any modification, substitution, and improvement of the relevant elements, components, and process steps without departing from the teaching of the present application.

[0055] It should be noted that the words "contain" or "comprise" in the claims do not preclude the presence of elements or assemblies not listed in the claims. The article "a" or "an" preceding a component or assembly does not preclude the presence of more than one such component or assembly.

[0056] Furthermore, it should be noted that the language used in this description serves primarily for readability and instruction, and not for the explanation or definition of the subject matter of this application. Therefore, many modifications and changes can be made by a person skilled in the art without deviating from the core and scope of the attached claims. As regards the scope of this application, the descriptions provided here are illustrative and not limiting, and the scope of this application is limited by the attached claims.

Claims

[1] Gamma camera imaging technique, which includes: Select (S101) from energy spectra recorded by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material, as one or more monitored energy ranges of the radioactive material; Performing (S102) an image reconstruction on the monitored energy ranges of each radioactive material among the one or more radioactive materials; Performing (S103) a normalization of the images obtained by image reconstruction; and Performing (S104) a superposition on the normalized images to produce a composite image, characterized by , that the selection includes: Sweeping through the energy spectra to find peaks and comparing the peaks with energies of branches of respective radioactive materials recorded in a predetermined nuclide bank to determine the one or more radioactive materials; Determine, for each radioactive material among the one or more radioactive materials, a portion of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material to be monitored; and Determine, for each branch of the one or more branches, an energy range of the radioactive material centered on a central energy of the branch and having a width of half a height width of a peak corresponding to the branch as one of the one or more monitored energy ranges of the radioactive material. [2] Gamma camera imaging method according to claim 1, further comprising: Determine, for each of the images obtained through image reconstruction, whether there is a closed area in the image; and adaptive adjustment, in a case where a closed area is present in the image, and if a ratio of the contrast of the closed area with respect to the contrast of a background area outside the closed area is less than a predetermined threshold, of the energy ranges of the monitored energy ranges according to the image. [3] Gamma camera imaging method according to claim 2, wherein the adaptive adjustment comprises: Gradual reduction or decrease of an energy range to be set in a predetermined energy step until the ratio of the contrast of the closed area to the contrast of a background area outside the closed area reaches the predetermined threshold. [4] Gamma camera imaging method according to claim 2, further comprising: Discarding the energy ranges of the monitored energy ranges that correspond to the image if there is no closed area in the image. [5] Gamma camera imaging method according to claim 2, further comprising: Discarding the energy ranges of the monitored energy ranges that correspond to the image after a predetermined time period if no closed area is present in the image. [6] Gamma camera imaging method according to claim 1, wherein the superposition comprises: Overlaying the normalized images in different color channels to form the composite image. [7] Gamma camera imaging device comprising: a selection module (801) configured to select, from energy spectra acquired by a gamma camera on one or more radioactive materials, one or more energy ranges of each radioactive material among the one or more radioactive materials as one or more monitored energy ranges of the radioactive material; an image reconstruction module (802) configured to perform image reconstruction on the monitored energy ranges of each radioactive material among the one or more radioactive materials; a normalization module (803) configured to perform normalization of the images obtained by image reconstruction; and an overlay module (804) configured to perform an overlay on the normalized images to produce a composite image, characterized by , that the selection module (801) includes: a peak detection module (8011) configured to traverse the energy spectra to find peaks and compare the peaks with energies of branches of the respective radioactive materials recorded in a predetermined nuclide bank to determine the one or more radioactive materials; a branch identification module (8012) configured to identify, for each radioactive material among the one or more radioactive materials, a portion of branches of the radioactive material with a relatively higher branch ratio or lower energy than one or more branches of the radioactive material being monitored; and an energy range determination module (8013) configured to determine for each branch of the one or more branches of the radioactive material an energy range centered on a central energy of the branch and having a width of a half-height width of a peak corresponding to the branch as one of the one or more monitored energy ranges of the radioactive materials. [8] Gamma camera imaging device according to claim 7, wherein the image reconstruction module (802) comprises: a module (8021) for determining a closed region, configured to determine for each of the images obtained by image reconstruction whether there is a closed region in the image; and an energy range adjustment module (8022) configured to adaptively adjust the energy ranges of the monitored energy ranges according to the image in a case where there is a closed area in the image and when the ratio of the contrast of the closed area to the contrast of a background area outside the closed area is less than a predetermined threshold. [9] Gamma camera imaging device according to claim 8, wherein the energy range determination module (8013) is further configured to gradually increase or decrease an energy range to be set in a predetermined energy step until the ratio of the contrast of the closed area to the contrast of a background area outside the closed area reaches the predetermined threshold. [10] Gamma camera imaging device according to claim 8, wherein the image reconstruction module (802) further comprises: a rejection module (8023) configured to reject the energy ranges of the monitored energy ranges according to the image in a case where there is no closed area in the image. [11] Gamma camera imaging device according to claim 8, wherein the image reconstruction module (802) further comprises: a rejection module (8023) configured to reject, in a case where there is no closed area in the image, the energy ranges of the monitored energy ranges corresponding to the image after a predetermined time period. [12] Gamma camera imaging device comprising: a memory (902) that stores instructions; and a processor (901) configured to execute the instructions stored in memory (902) to perform the gamma camera imaging method according to any one of claims 1-6. [13] Computer-readable storage medium that stores instructions which can be executed by a processor to perform the gamma camera imaging method according to any one of claims 1 to 6. [14] Gamma camera, comprehensive: the gamma camera imaging device according to one of claims 7-12.

Images