A Compton detector spatial distribution dynamic detection method and system

Abstract

The present invention relates to the field of medical equipment technology, and discloses a dynamic detection method and system for the spatial distribution of Compton detectors. The method comprises determining a high-radioactivity region of a scanned object; determining a detector distribution spatial region relative to the scanned object; determining a radioactive attenuation degree based on the detector distribution spatial region; determining the number of Compton detectors to be arranged in the detector distribution spatial region based on the radioactive attenuation degree; and detecting the high-radioactivity region using the number of arranged Compton detectors; wherein the number of arranged Compton detectors increases with an increase in the radioactive attenuation degree. In this manner, the detection time can be shortened, image reconstruction artifacts can be reduced, and the difference in resolution of images reconstructed at different angles in three-dimensional space can be reduced, thereby reflecting a more realistic radionuclide distribution. Higher-quality radionuclide distribution images can be reconstructed at lower activity levels, providing selectable angle detection information for reconstructing three-dimensional images.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to a method and system for dynamic detection of spatial distribution of Compton detectors. Background Art

[0002] In modern medicine, nuclear medicine imaging plays an irreplaceable role in disease diagnosis, treatment evaluation, and pathological research. It non-invasively provides information on the distribution of radionuclides within the human body, facilitating early tumor detection, organ function assessment, and disease progression monitoring. However, with the continuous development of nuclear medicine, the requirements for imaging technology are also increasing.

[0003] A Compton detector is a gamma-ray detector based on electronic collimation. It has the advantages of high detection efficiency, a wide detection energy range, and a large imaging field of view. It is currently widely used in astronomical detection and environmental radiation monitoring, and has great development potential in the field of nuclear medicine imaging. However, there are currently some problems in the clinical application of Compton detectors. Because the Compton detector reconstructs the image by back-projecting a cone surface into the imaging space based on the detected Compton events, this reconstruction principle leads to artifacts in the reconstructed image, and there are significant differences in the reconstruction resolution on different planes, which seriously affects the reconstruction performance of a single Compton detector in three-dimensional space. Current clinical imaging equipment usually uses tomography methods to reduce reconstruction artifacts through multi-angle detection, and moves the detection equipment to scan layer by layer to achieve three-dimensional reconstruction. This process results in a long detection cycle and the scanned object needs to withstand additional doses. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method and system for dynamic detection of spatial distribution of Compton detectors.

[0005] In a first aspect, the present invention provides a method for dynamic detection of spatial distribution of Compton detectors, comprising:

[0006] S101, determining a high radioactivity area of ​​a scanned object; wherein a difference in radioactivity between the high radioactivity area and a non-high radioactivity area is greater than an activity threshold;

[0007] S102, determining a detector distribution spatial area relative to the scan object;

[0008] S103, determining the degree of radioactive attenuation based on the detector distribution spatial area;

[0009] S104, determining the number of Compton detectors to be arranged in the detector distribution space based on the radioactive attenuation degree;

[0010] S105, detecting the high radioactivity area based on the arranged number of Compton detectors;

[0011] The number of Compton detectors increases as the degree of radioactive attenuation increases.

[0012] Optionally, determining a high radioactivity area of ​​the scanned object includes:

[0013] determining a lesion area of ​​the scanned object and determining a radioactive attenuation coefficient;

[0014] Evenly surrounding the lesion area with a target number of pairs of Compton detectors;

[0015] determining a number of Compton events in a first detection period by the Compton detector of the target number of pairs;

[0016] The high radioactivity region is determined based on the number of Compton events and the radioactive attenuation coefficient.

[0017] Optionally, determining the high radioactivity region based on the number of Compton events and the radioactive attenuation coefficient includes:

[0018] determining a high radioactivity location based on the number of Compton events corresponding to each pair of Compton detectors;

[0019] amplifying the difference between the high radioactivity region and the non-high radioactivity region by an activation function to determine an initial high radioactivity region;

[0020] The high radioactivity region is determined by combining all the initial high radioactivity regions corresponding to the Compton detectors.

[0021] Optionally, determining a detector distribution spatial region relative to the scanned object includes:

[0022] Determining a distribution sphere with the imaging space center position of the scanned object as the sphere center;

[0023] Determining the detector distribution spatial area based on the distribution sphere;

[0024] Wherein, the angles between any of the detector distribution space regions and the center of the sphere are equal.

[0025] Optionally, determining the degree of radioactive attenuation based on the detector distribution spatial area includes:

[0026] The radioactive attenuation degree is determined based on the distance between the high radioactive activity area and the detector distribution space area and the radioactive attenuation coefficient.

[0027] Optionally, the number of arrangements is greater than the number of Compton detectors corresponding to the number of targets.

[0028] Optionally, after detecting the high radioactivity area using the arranged number of Compton detectors, the method further includes:

[0029] Reconstruct a 3D image based on the detection results.

[0030] In a second aspect, the present invention further provides a Compton detector spatial distribution dynamic detection system for implementing the method described in any one of the first aspects; the system comprises:

[0031] Slide rails are set around the testing bed;

[0032] At least the arranged number of Compton detectors are fixed on the slide rail and slide freely along the slide rail.

[0033] Optionally, the slide rail is a spiral slide rail.

[0034] The embodiments of the present invention have the following technical effects:

[0035] In the detection method provided by the present invention, the high radioactivity area is first determined by a Compton detector, and then the number of Compton detectors in the spatial distribution area of ​​each detector is determined according to the attenuation degree. Since there is no need to scan layer by layer with a single Compton detector, the detection time can be effectively shortened and the dose borne by the scanned object can be reduced. By optimizing the design of the spatial distribution of detectors, the image reconstruction artifacts of the Compton detector can be effectively reduced, the difference in the resolution of the reconstructed images at different angles in three-dimensional space can be reduced, and a better and more realistic radionuclide distribution can be reflected. Multiple Compton detectors can obtain detection information from multiple angles, and higher-quality radionuclide distribution images can be reconstructed at lower activities. In addition, the position of the Compton detector can be dynamically adjusted according to the data received in real time by the Compton detector during the detection process, so that selectable angle detection information can be provided for reconstructing three-dimensional images. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic flow chart of a method for dynamic detection of spatial distribution of Compton detectors provided in an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a high radioactivity area detection scenario provided by an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of another high radioactivity area detection scenario provided by an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the distribution of Compton detectors provided in an embodiment of the present invention;

[0041] Figure 5 A schematic structural diagram of a Compton detector spatial distribution dynamic detection system provided by an embodiment of the present invention.

[0042] Reference numerals

[0043] A0, high radioactivity area; A1, Compton detector; A2, slide rail; A3, detection bed; A4, scanning object. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0045] Figure 1 A schematic flow chart of a method for dynamic detection of spatial distribution of Compton detectors provided in an embodiment of the present invention. The method can be controlled and executed by a controller, and the method includes:

[0046] S101, determining a high radioactivity area of ​​the scanned object, wherein the difference in radioactivity between the high radioactivity area and the non-high radioactivity area is greater than an activity threshold;

[0047] Specifically, the scanned object can be a human body, and the embodiments of the present invention are described using the human body as an example. A high radioactivity region refers to an area with high radioactivity, and its notable characteristic is that the radioactivity in the region is significantly higher than that in other areas (i.e., the radioactivity difference is higher than the activity threshold).

[0048] In some embodiments, determining a region of high radioactivity in a scanned object includes:

[0049] Determine the lesion area of ​​the scanned object and determine the radioactive attenuation coefficient.

[0050] The target number of pairs of Compton detectors are evenly placed around the lesion area.

[0051] The number of Compton events in a first detection cycle is determined by a target number of pairs of Compton detectors.

[0052] Areas of high radioactivity are identified based on the number of Compton events and the radioactive decay coefficient.

[0053] Specifically, for example, if the lesion region of the scanned subject is the head, in the process of determining the region of high radioactivity in the scanned subject, multiple pairs of Compton detectors can be used to surround the lesion region, such as the head. In practical applications, the attenuation degree of the imaging space can be calculated from the CT image.

[0054] In some embodiments, determining a region of high radioactivity based on the number of Compton events and the radioactivity attenuation coefficient comprises:

[0055] The locations of high radioactivity are determined based on the number of Compton events corresponding to each pair of Compton detectors.

[0056] The difference between the high radioactivity area and the non-high radioactivity area is amplified by the activation function to determine the initial high radioactivity area.

[0057] The high radioactivity region is determined by combining the initial high radioactivity regions corresponding to all pairs of Compton detectors.

[0058] After research, it was found that the probability of a photon emitted by a high radioactivity region being detected by a Compton detector is inversely proportional to the degree of attenuation of the high radioactivity region on the path through the tissue before reaching the Compton detector, and is inversely proportional to the square of the distance between the high radioactivity region and the Compton detector. So for any point P in the tissue, the number of Compton events detected by Compton detector 1 and Compton detector 2 from position P is and The ratios are as follows:

[0059]

[0060] in, represents the number of Compton events detected by Compton detector 1, represents the number of Compton events detected by Compton detector 1, represents the attenuation degree at the location of Compton detector 1, represents the attenuation degree at the location of Compton detector 2, represents the distance between the high radioactivity area and Compton detector 1, Indicates the distance between the high radioactivity area and Compton detector 2. Figure 2A schematic diagram of a high radioactivity area detection scenario provided by an embodiment of the present invention. Figure 2 As shown in (a), Figure 2 (a) shows the actual location of the high-radioactivity acquisition area (still unknown at this time) A0, and a pair of Compton detectors A1.

[0061] For example, the two Compton detectors measured 9151 and 16106 Compton events respectively, with a ratio of 0.568. Therefore, it can be considered that the high radioactivity area is located in Figure 2 (b) The pixel with a ratio of 0.568. However, the difference between this pixel and other pixels is small, so the activation function

[0062]

[0063] By amplifying the difference between the pixel with a magnification ratio of 0.568 and other pixels, we can obtain the initial high radioactivity area when the Compton detector count ratio is 0.568, such as Figure 2 (c) shows an arc shape, and the exact location of the high radioactivity area cannot be accurately located at this time. represents the ratio of the number of Compton events.

[0064] Therefore, in the embodiment of the present invention, multiple pairs of Compton detectors are provided. Figure 3 This is another schematic diagram of a high radioactivity area detection scenario provided by an embodiment of the present invention. Figure 3 As shown in (a), Figure 3 (a) Four pairs of Compton detectors A1 are set (ie the target number of pairs can be 4 pairs), in order to distinguish Figure 3 In (a), different Compton detectors are distinguished by brackets, A1, 1-8, and the high radioactivity region is shown as A0. Each pair of Compton detectors can obtain an initial high radioactivity region, such as Figure 3 By combining all the initial high radioactivity regions, the high radioactivity regions can be obtained as Figure 3 (c) Theoretically, when Compton detector counts reach a sufficient level to reduce statistical error to an acceptable level, this method can be used to locate areas of high radioactivity. The advantage of this method is that it eliminates the need for imaging reconstruction and relies solely on Compton detector counts to rapidly locate areas of high radioactivity.

[0065] S102: Determine a detector distribution spatial area relative to the scan object.

[0066] After determining the high radioactivity area, the detector distribution space area is further determined.

[0067] In some embodiments, determining a detector distribution spatial region relative to the scanned object includes:

[0068] The distribution sphere is determined with the imaging space center position of the scanned object as the sphere center.

[0069] The detector distribution space area is determined based on the distribution sphere.

[0070] Among them, the angle between any detector distribution space area and the center of the sphere is equal.

[0071] For example, a sphere with a radius of r and the center of the imaging space of the scanned object as the center can be set. For a 4π imaging space, every 30° can be used as a detector distribution space area. For example, each detector distribution space area on the sphere is a quadrilateral with equal sides, and the angle between the midpoints of the two opposite sides of each detector distribution space area and the center of the sphere can be 30°. The same applies to detector distribution space areas of other shapes. In other words, it can be understood that the embodiment of the present invention arranges Compton detectors for each detector distribution space area as a unit. For the center position of the imaging space, the distance between the Compton detector and the center of the sphere is equal. For high radioactivity areas, the distance between different Compton detectors and the high radioactivity area may be the same or different. Figure 4 A schematic diagram of the distribution of Compton detectors provided in an embodiment of the present invention is shown. Figure 4 The scanning object A4 shown in the figure can be a human brain, so it is shown as an ellipse. The scanning object A4 can be located at the center of the imaging space. In the embodiment of the present invention, the Compton detector A1 can be arranged with the center point of the imaging center as the center of the sphere.

[0072] S103. Determine the degree of radioactive attenuation based on the detector distribution spatial area.

[0073] In some embodiments, determining the extent of radioactivity attenuation based on the spatial distribution of detectors comprises:

[0074] The degree of radioactive attenuation is determined based on the distance between the high radioactive activity area and the detector distribution space area and the radioactive attenuation coefficient.

[0075] After determining the detector spatial distribution area, the distance between the detector distribution area and the high radioactivity area can be determined. Generally speaking, the greater the distance, the higher the degree of radioactivity attenuation, that is, the lower the radioactivity, the more difficult it is to detect.

[0076] S104: Determine the number of Compton detectors to be arranged in the detector distribution space based on the radioactive attenuation degree, wherein the number of Compton detectors to be arranged increases as the radioactive attenuation degree increases.

[0077] In some embodiments, the number of arrangements is greater than the number of targets corresponding to the number of Compton detectors.

[0078] Based on S103, the embodiment of the present invention determines the number of Compton detectors to be deployed based on the distance between the detector distribution space and the high radioactivity area. The larger the distance, the greater the degree of radioactive attenuation and the lower the radioactivity, and therefore the higher the number of Compton detectors to be deployed. In the above embodiment, the embodiment of the present invention determines the high radioactivity area using 8 Compton detectors. In this step, the embodiment of the present invention can detect the high radioactivity area using 36 Compton detectors, such as Figure 4 A schematic diagram of the distribution of Compton detectors provided by an embodiment of the present invention. In the figure, A0 represents a high radioactivity area, and A1 represents a Compton detector.

[0079] Based on the above solution, the embodiment of the present invention has achieved the number of strong and weak Compton detectors based on the radioactivity at the location of the Compton detector.

[0080] S105. Detect high radioactivity areas based on the number of deployed Compton detectors.

[0081] After the Compton detectors are arranged, detection at multiple angles can be achieved through the Compton detectors.

[0082] In summary, the embodiment of the present invention first determines the high radioactivity area through the Compton detector, and then determines the number of Compton detectors in each detector spatial distribution area according to the attenuation degree. Since there is no need to scan layer by layer through a single Compton detector, the detection time can be effectively shortened and the dose borne by the scanned object can be reduced. By optimizing the design of the spatial distribution of detectors, the image reconstruction artifacts of the Compton detector can be effectively reduced, the difference in the resolution of the re-encoded images at different angles in three-dimensional space can be reduced, and a better reflection of the true distribution of radioactive nuclides can be achieved. Multiple Compton detectors can obtain detection information from multiple angles, and higher-quality radioactive nuclide distribution images can be reconstructed at lower activities. In addition, the position of the Compton detector can be dynamically adjusted according to the data received in real time by the Compton detector during the detection process, so as to provide selectable angle detection information for reconstructing three-dimensional images.

[0083] In some embodiments, after detecting the high radioactivity area based on the number of deployed Compton detectors, the method further includes:

[0084] Reconstruct a 3D image based on the detection results.

[0085] Specifically, after detecting high-activity areas of the scanned object using a Compton detector, a 3D image can be reconstructed based on the detection results. The reconstructed 3D image effectively reduces artifacts and features high resolution and excellent consistency, as described in detail above and will not be repeated here.

[0086] An embodiment of the present invention further provides a Compton detector spatial distribution dynamic detection system for implementing any one of the above method embodiments. Figure 5 A schematic diagram of the structure of a Compton detector spatial distribution dynamic detection system provided by an embodiment of the present invention, the system includes:

[0087] The slide rail A2 is arranged around the inspection bed A3.

[0088] At least a number of Compton detectors A1 are fixed on the slide rail A2 and can slide freely along the slide rail A2.

[0089] Continue reading Figure 5 In some embodiments, the slide rail A2 is a spiral slide rail.

[0090] In addition, the system further includes a controller (not shown) electrically connected to the slide rail and / or the detector, and the controller can control the Compton detector A1 to slide along the slide rail A2 to move its position. Figure 5 The A4 in the figure indicates the scanned object.

[0091] Specifically, Compton detectors A1 can be distributed axially and circumferentially around the high-activity region A0, increasing the detection angle of Compton detectors A1 and improving the accuracy of the reconstructed three-dimensional image. In this way, Compton detectors A1 can be placed around the high-activity region A0, scanning the high-activity region from multiple angles.

[0092] It should be noted that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the scope of this application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular and may also include the plural. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, the elements defined by the sentence "comprise a..." do not exclude the presence of other identical elements in the process, method or device comprising the elements.

[0093] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A Compton detector spatial distribution dynamic detection method, characterized in that: include: S101, determining a high radioactivity area of ​​a scanned object; wherein a difference in radioactivity between the high radioactivity area and a non-high radioactivity area is greater than an activity threshold; S102, determining a detector distribution spatial area relative to the scan object; S103, determining the degree of radioactive attenuation based on the detector distribution spatial area; S104, determining the number of Compton detectors to be arranged in the detector distribution space based on the radioactive attenuation degree; S105, detecting the high radioactivity area based on the arranged number of Compton detectors; The number of Compton detectors increases as the degree of radioactive attenuation increases. Determining a detector distribution spatial region relative to the scanned object includes: Determining a distribution sphere with the imaging space center position of the scanned object as the sphere center; Determining the detector distribution spatial area based on the distribution sphere; Wherein, the angle between any of the detector distribution space regions and the center of the sphere is equal; Determining the degree of radioactive attenuation based on the detector distribution spatial area includes: The radioactive attenuation degree is determined based on the distance between the high radioactive activity area and the detector distribution space area and the radioactive attenuation coefficient.

2. The method according to claim 1, characterized in that Identify areas of high radioactivity within the scanned object, including: determining a lesion area of ​​the scanned object and determining a radioactive attenuation coefficient; Evenly surrounding the lesion area with a target number of pairs of Compton detectors; determining a number of Compton events in a first detection period by the Compton detector of the target number of pairs; The high radioactivity region is determined based on the number of Compton events and the radioactive attenuation coefficient.

3. The method according to claim 2, characterized in that Determining the high radioactivity area based on the number of Compton events and the radioactive attenuation coefficient includes: determining a high radioactivity location based on the number of Compton events corresponding to each pair of Compton detectors; amplifying the difference between the high radioactivity region and the non-high radioactivity region by an activation function to determine an initial high radioactivity region; The high radioactivity region is determined by combining all the initial high radioactivity regions corresponding to the Compton detectors.

4. The method according to claim 2, characterized in that The number of arrangements is greater than the number of Compton detectors corresponding to the number of targets.

5. The method according to claim 1, wherein After the Compton detectors arranged in the number detect the high radioactivity area, the method further includes: Reconstruct a 3D image based on the detection results.

6. A Compton detector spatial distribution dynamic detection system, characterized in that: Used to implement the method according to any one of claims 1 to 5; the system comprises: Slide rails are set around the testing bed; At least the arranged number of Compton detectors are fixed on the slide rail and slide freely along the slide rail.

7. The system according to claim 6, characterized in that The slide rail is a spiral slide rail.

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