Method for spatial positioning of a radioactive source and positioning system

Abstract

The application relates to a radioactive source spatial positioning method and a positioning system. The spatial positioning method comprises the following steps: providing a first detection device and a second detection device, which are arranged at a predetermined angle interval, the first detection device has a first detection range, the second detection device has a second detection range, and the first detection range and the second detection range intersect to form a positioning detection area; acquiring a first image and a second image including a radioactive source in the positioning detection area respectively; acquiring the position of a first bisector intersecting with the radioactive source in the first image from a plurality of bisectors formed by equally dividing the first detection range at a first angular resolution interval; acquiring the position of a second bisector intersecting with the radioactive source in the second image from a plurality of bisectors formed by equally dividing the second detection range at a second angular resolution interval; and acquiring the intersection position of the first bisector and the second bisector according to the position of the first bisector and the position of the second bisector, so that the intersection position is the spatial position of the radioactive source.

Description

Technical Field

[0001] This application relates to the field of radiation detection technology, and in particular to a spatial positioning method and positioning system for a radioactive source. Background Technology

[0002] With the development of my country's nuclear science and technology, the requirements for nuclear safety and radiation monitoring of radioactive sources are constantly increasing. In practical applications, accurately locating the spatial distribution of radioactive sources is crucial for improving nuclear safety regulatory capabilities, and it has wide applications in fields such as industrial and medical radioactive source safety management, nuclear accident emergency response, environmental radiation monitoring, and public safety.

[0003] In practical applications, accurate location of radiation sources is crucial. However, due to limitations such as the limited number of pixels in current gamma radiation array detectors and the inability to reduce the aperture of the encoder plate, it is currently impossible to overcome the pixel limitations at the physical measurement level to achieve higher-resolution radioactive imaging, thus hindering the rapid and accurate location of radiation sources. Summary of the Invention

[0004] The purpose of this application is to provide a spatial positioning method and system for a radioactive source, which can obtain a relatively accurate spatial location of the radioactive source in a short time.

[0005] On one hand, embodiments of this application provide a spatial positioning method for a radioactive source, comprising: providing a first detection device and a second detection device, the first detection device and the second detection device being arranged at a predetermined angular interval, the first detection device having a first detection range, the second detection device having a second detection range, and the area where the first detection range and the second detection range intersect forming a positioning detection area; acquiring a first image and a second image including the radioactive source in the positioning detection area by the first detection device and the second detection device respectively; acquiring the position of the first bisector line intersecting the radioactive source in the first image from multiple first bisector lines formed by dividing the first detection range at a first angular resolution interval, and acquiring the position of the second bisector line intersecting the radioactive source in the second image from multiple second bisector lines formed by dividing the second detection range at a second angular resolution interval; and acquiring the intersection point of the first bisector line and the second bisector line based on the positions of the first bisector line and the second bisector line, wherein the intersection point is the spatial position of the radioactive source.

[0006] According to one aspect of the embodiments of this application, the first detection device and the second detection device are located in the same plane.

[0007] According to one aspect of the embodiments of this application, the predetermined angle between the first detection device and the second detection device is 45°.

[0008] According to one aspect of the embodiments of this application, a proportional relationship between a first distance between the first detection device and the radiation source and a second distance between the second detection device and the radiation source is determined based on the number of first rays measured by the first detection device per unit time in the positioning detection area and the number of second rays measured by the second detection device per unit time in the positioning detection area; a corrected spatial position of the radiation source is determined based on the proportional relationship between the first distance and the second distance and the relative positional relationship between the first detection device and the second detection device; if the distance between the spatial position of the radiation source and the corrected spatial position is greater than a threshold, the relative positional relationship between the first detection device and the second detection device is readjusted to redetermine the spatial position of the radiation source.

[0009] According to one aspect of the embodiments of this application, when the distance between the first detection device or the second detection device and the radiation source is L, the first emission number per unit time is N1, and the second ray number emitted by the radiation source per unit time is N2. Then, the first emission number N1, the distance L, and the second ray number N2 satisfy the following relationship:

[0010]

[0011] According to one aspect of the embodiments of this application, when the first distance between the first detection device and the radiation source is L1, the number of third rays measured per unit time in the positioning detection area is N3; when the second distance between the second detection device and the radiation source is L2, the number of fourth rays measured per unit time in the positioning detection area is N4. Then, the number of third rays N3, the number of fourth rays N4, the first distance L1, and the second distance L2 satisfy the following relationship:

[0012]

[0013] On the other hand, this application embodiment also provides a spatial positioning system for a radioactive source, including: a first detection device and a second detection device, the first detection device and the second detection device being arranged at a predetermined angular interval, the first detection device having a first detection range, the second detection device having a second detection range, the area where the first detection range and the second detection range intersect forming a positioning detection area, the first detection device and the second detection device being respectively used to acquire a first image and a second image including a radioactive source in the positioning detection area; a calculation unit, configured to: acquire the position of a first bisector line intersecting the radioactive source in the first image from multiple first bisector lines formed by equally dividing the first detection range at a first angular resolution interval; acquire the position of a second bisector line intersecting the radioactive source in the second image from multiple second bisector lines formed by equally dividing the second detection range at a second angular resolution interval; and acquire the intersection point position of the first bisector line and the second bisector line based on the positions of the first bisector line and the second bisector line, wherein the intersection point position is the spatial position of the radioactive source.

[0014] According to one aspect of the embodiments of this application, the calculation unit is further configured to: determine the proportional relationship between a first distance between the first detection device and the radiation source and a second distance between the second detection device and the radiation source based on the number of first rays measured by the first detection device per unit time in the positioning detection area and the number of second rays measured by the second detection device per unit time in the positioning detection area; determine the corrected spatial position of the radiation source based on the proportional relationship between the first distance and the second distance and the relative positional relationship between the first detection device and the second detection device; and if the distance between the spatial position of the radiation source and the corrected spatial position is greater than a threshold, readjust the relative positional relationship between the first detection device and the second detection device to redetermine the spatial position of the radiation source.

[0015] According to one aspect of the embodiments of this application, the first detection device or the second detection device further includes a meter for measuring the number of rays from the radiation source per unit time.

[0016] According to one aspect of the embodiments of this application, the first detection device and the second detection device are coded gamma cameras or Compton gamma cameras.

[0017] This application provides a spatial positioning method and system for radioactive sources. This spatial positioning method can quickly calculate the spatial location of a radioactive source by using the geometric positional relationship of the source in images captured by at least two detectors placed at a predetermined angle. Compared to related technologies that suffer from large positioning errors, high computational load, and long calculation times, this spatial positioning method can obtain a relatively accurate spatial location of the radioactive source in a short time and is easy to promote and use. Attached Figure Description

[0018] The features, advantages, and technical effects of exemplary embodiments of the present application will now be described with reference to the accompanying drawings. In the drawings, the same parts are referred to by the same reference numerals. The drawings are not drawn to scale.

[0019] Figure 1 A flowchart illustrating a method for spatially locating a radioactive source according to an embodiment of this application is shown.

[0020] Figure 2 Show Figure 1 A schematic diagram of the scenario in which the first and second detection devices in the spatial positioning method detect a radioactive source.

[0021] Figure 3 Show Figure 2 A schematic diagram showing the position comparison of the radioactive source in the first and second images;

[0022] Figure 4A schematic diagram showing the geometric relationship between the first and second detection devices and the radiation source is shown. Detailed Implementation

[0023] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples. In the accompanying drawings and the following description, at least some well-known structures and techniques are not shown to avoid unnecessarily obscuring the application; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0024] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0025] See Figures 1 to 3 This application provides a method for spatial positioning of a radioactive source, including steps S1 to S4 as described below.

[0026] In step S1, a first detection device 1 and a second detection device 2 are provided. The first detection device 1 and the second detection device 2 are set at a predetermined angular interval. The first detection device 1 has a first detection range D1, and the second detection device 2 has a second detection range D2. The area where the first detection range D1 and the second detection range D2 intersect forms a positioning detection area T.

[0027] like Figure 2 As shown, the first detection device 1 and the second detection device 2 can be either coded gamma cameras or Compton gamma cameras. For ease of explanation, this embodiment uses coded gamma cameras as an example.

[0028] The first detection device 1 and the second detection device 2 are arranged at a predetermined angular interval. The first detection device 1 has a first detection range D1, and the second detection device 2 has a second detection range D2. The area where the first detection range D1 and the second detection range D2 intersect forms a positioning detection area T. The first detection range D1 and the second detection range D2 are two-dimensional detection areas, and the first detection device 1 and the second detection device 2 have two-dimensional imaging capabilities within these areas. The positioning detection area T is a three-dimensional detection area, and the system can locate radioactive sources within this area.

[0029] The first detection device 1 and the second detection device 2 employ Anger's principle for imaging, including a collimator, multiple detectors, and electronic components. They can image rays with energy ranges from E1 to E2. To ensure that only incident photons along a specific path are detected, a collimator is used for collimation. Pinhole collimators are commonly used. Pinhole collimators utilize the principle of pinhole imaging to project a picture of the area to be detected. The image size can be a specific proportion of the original image to improve positional resolution. The detectors in the first detection device 1 include a first scintillator 12 and several first photomultiplier tubes 11, while the detectors in the second detection device 2 include a second scintillator 22 and several first and second photomultiplier tubes 21. These convert incident gamma rays into detectable photons, which are then photoelectrically converted and amplified by the photomultiplier tubes 11 and 21, outputting a measurable electrical signal. The electronic components process and calculate the signal output from the probes. The photomultiplier tubes 11 and 21 at corresponding positions in the probe will generate electrical signals of different amplitudes. The amplitude is proportional to the energy of the incident photon. By processing the signals with the corresponding algorithm, the position and energy information of the incident photon can be obtained.

[0030] Furthermore, the first detection device 1 and the second detection device 2 also include an encoding plate, which is generally a planar plate. Some areas on the plate are transparent to photons with energies between E1 and E2, while other areas are opaque to such photons. The transparent and opaque areas are called "encoding elements," have the same size, and are distributed in a predetermined manner, such as Fresnel zones or random pinhole patterns. The detector's positional resolution matches the encoding apertures, and it is only sensitive to photons with energies between E1 and E2. Multiple rays emitted from the radiation source pass through the transparent areas (also called encoding apertures) on the encoding plate and illuminate the detector. The detector records projections of multiple encoding aperture patterns. Each projection encodes the corresponding point source position of the radiation source, and the intensity of each projection constitutes the encoding of the corresponding point source intensity. Based on the projection information obtained by the detector, the distribution of the radiation source can be deduced.

[0031] In step S2, the first image P1 and the second image P2, including the radioactive source RS, are acquired in the positioning detection area T by the first detection device 1 and the second detection device 2, respectively.

[0032] Because the first detection device 1 and the second detection device 2 are placed in different positions, the two-dimensional images formed for the same radiation source will also differ in geometric position. Figure 3 The images shown are a first image P1 and a second image P2 obtained by the first detection device 1 and the second detection device 2 respectively performing two-dimensional imaging on the same point-shaped radioactive source RS. Both images are square. In the first image P1, the radioactive source RS is approximately located in the center of the square region. In the second image P2, the radioactive source RS is approximately located at the edge of the square region.

[0033] In step S3, the position of the first bisector PL1 intersecting the radioactive source RS in the first image P1 is obtained from the multiple first bisector PL1 formed by dividing the first detection range D1 into multiple first bisectors PL1 with a first angular resolution interval; and the position of the second bisector PL2 intersecting the radioactive source RS in the second image P2 is obtained from the multiple second bisector PL2 formed by dividing the second detection range D2 into multiple second bisectors PL2 with a second angular resolution interval.

[0034] The angular resolution of the first detection device 1 and the second detection device 2 depends on the number of pixels in the detector. The first angular resolution and the second angular resolution can be the same or different. The position of the first bisector PL1 intersecting the radioactive source RS in the first image P1 is obtained, and the position or number of the detector corresponding to the first bisector PL1 is recorded. The position of the second bisector PL2 intersecting the radioactive source RS in the second image P2 is obtained, and the position or number of the detector corresponding to the second bisector PL2 is recorded.

[0035] In step S4, the intersection point of the first bisector PL1 and the second bisector PL2 is obtained based on the position of the first bisector PL1 and the position of the second bisector PL2. The intersection point is the spatial position of the radioactive source RS.

[0036] It is understood that the spatial positioning method of the radiation source in the embodiments of this application is applicable not only to coded gamma cameras, but also to Compton gamma cameras, or other gamma cameras, which will not be elaborated further.

[0037] This application provides a spatial positioning method and system for radioactive sources. This spatial positioning method can quickly calculate the spatial location of a radioactive source by using the geometric positional relationship of the source in images captured by at least two detectors placed at a predetermined angle. Compared to related technologies that suffer from large positioning errors, high computational load, and long calculation times, this spatial positioning method can obtain a relatively accurate spatial location of the radioactive source in a short time and is easy to promote and use.

[0038] In some embodiments, such as Figure 2 As shown, the first detection device 1 and the second detection device 2 are located in the same plane. This arrangement saves space and reduces the computational workload of locating the X-ray source RS. Further optionally, the predetermined angle between the first detection device 1 and the second detection device 2 is 45°.

[0039] In some embodiments, the spatial positioning method for the radioactive source further includes steps S5 to S7.

[0040] In step S5, the proportional relationship between the first distance between the first detection device 1 and the radiation source RS and the second distance between the second detection device 2 and the radiation source RS is determined based on the number of first rays measured by the first detection device 1 per unit time in the positioning detection area T and the number of second rays measured by the second detection device 2 per unit time in the positioning detection area T.

[0041] First, when the distance between the first detection device 1 or the second detection device 2 and the radiation source RS is L, the first emission number is measured as N1, and the second ray number emitted by the radiation source RS per unit time is N2. Then, the first emission number N1, the distance L, and the second ray number N2 satisfy the following relationship:

[0042]

[0043] When the radiation source remains unchanged It can be considered a constant, at this time In practical applications, the value of N1 in the formula, i.e., the counting rate of the detection device, can be obtained from the first detection device 1 or the second detection device 2.

[0044] Secondly, when the first distance between the first detection device 1 and the radiation source RS is L1, the number of third rays measured per unit time in the positioning detection area T is N3. When the second distance between the second detection device 2 and the radiation source RS is L2, the number of fourth rays measured per unit time in the positioning detection area T is N4. Then, the number of third rays N3, the number of fourth rays N4, the first distance L1, and the second distance L2 satisfy the following relationship:

[0045]

[0046] According to formula (1), the number of third rays N3 measured when the distance between the first detection device 1 and the radiation source RS is the first spacing L1, and the number of fourth rays N4 measured when the distance between the second detection device 2 and the radiation source RS is the second spacing L2, can be obtained from formula (2).

[0047] In step S6, the corrected spatial position of the radioactive source RS is determined based on the proportional relationship between the first spacing and the second spacing and the relative positional relationship between the first detection device 1 and the second detection device 2.

[0048] like Figure 4 As shown, given the distance L3 between the first detection device 1 and the second detection device 2, and the proportional relationship between the first spacing L1 and the second spacing L2, the specific values ​​of the first spacing L1 and the second spacing L2 can be obtained using the law of cosines. Draw a first circle with the first detection device 1 as the center and the first spacing L1 as the radius, and draw a second circle with the second detection device 2 as the center and the second spacing L2 as the radius. The intersection of the first circle and the second circle is the correction spatial position of the radioactive source RS.

[0049] In step S7, if the distance between the spatial position of the radioactive source RS and the corrected spatial position is greater than a threshold, the relative positional relationship between the first detection device 1 and the second detection device 2 is readjusted to redetermine the spatial position of the radioactive source RS. This allows for more precise positioning of the spatial position of the radioactive source RS.

[0050] It should be noted that the number of the first detection device 1 and the second detection device 2 in the embodiments of this application is not limited to one as shown in the figure, but can be more than one. Moreover, the more the number of the first detection device 1 and the second detection device 2, the more accurate the spatial positioning of the radiation source RS will be.

[0051] In addition, such as Figure 2 As shown in the figure, this application embodiment also provides a spatial positioning system for a radioactive source RS, including: a first detection device 1, a second detection device 2, and a computing unit.

[0052] The first detection device 1 and the second detection device 2 are set at a predetermined angular interval. The first detection device 1 has a first detection range D1, and the second detection device 2 has a second detection range D2. The area where the first detection range D1 and the second detection range D2 intersect forms a positioning detection area T. The first detection device 1 and the second detection device 2 are respectively used to acquire a first image P1 and a second image P2 including the radioactive source RS in the positioning detection area T.

[0053] The computing unit is configured to: obtain the position of the first bisector PL1 intersecting the radioactive source RS in the first image P1 within the multiple first bisector PL1 formed by dividing the first detection range D1 into multiple second bisector PL2s with a first angular resolution interval; obtain the position of the second bisector PL2 intersecting the radioactive source RS in the second image P2 within the multiple second bisector PL2 formed by dividing the second detection range D2 into multiple second bisector PL2s with a second angular resolution interval; and obtain the intersection point of the first bisector PL1 and the second bisector PL2 based on the positions of the first bisector PL1 and the second bisector PL2, wherein the intersection point is the spatial position of the radioactive source RS.

[0054] In some embodiments, such as Figure 2 As shown, the first detection device 1 and the second detection device 2 are located in the same plane. This arrangement saves space and reduces the computational workload of locating the X-ray source RS. Further optionally, the predetermined angle between the first detection device 1 and the second detection device 2 is 45°.

[0055] In some embodiments, the calculation unit is further configured to: determine the proportional relationship between a first distance between the first detection device 1 and the radiation source RS and a second distance between the second detection device 2 and the radiation source RS based on the number of first rays measured by the first detection device 1 per unit time in the positioning detection area T and the number of second rays measured by the second detection device 2 per unit time in the positioning detection area T; determine the corrected spatial position of the radiation source RS based on the proportional relationship between the first distance and the second distance and the relative positional relationship between the first detection device 1 and the second detection device 2; and if the distance between the spatial position of the radiation source RS and the corrected spatial position is greater than a threshold, readjust the relative positional relationship between the first detection device 1 and the second detection device 2 to redetermine the spatial position of the radiation source RS.

[0056] In some embodiments, the first detection device 1 or the second detection device 2 further includes a meter for measuring the number of rays from the radiation source RS per unit time.

[0057] This application provides a spatial positioning system for a radioactive source. By analyzing the geometric positional relationship of the radioactive source in images captured by at least two detectors placed at a predetermined angle, the spatial location of the radioactive source can be quickly calculated. Compared to related technologies, which suffer from large positioning errors, high computational load, and long calculation times, this spatial positioning method can obtain a relatively accurate spatial location of the radioactive source in a short time and is easy to promote and use.

[0058] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for spatially locating a radioactive source, characterized in that, include: A first detection device and a second detection device are provided, the first detection device and the second detection device are arranged at a predetermined angular interval, the first detection device has a first detection range, the second detection device has a second detection range, and the area where the first detection range and the second detection range intersect forms a positioning detection area; The first detection device and the second detection device respectively acquire a first image and a second image including the radiation source in the positioning detection area; In the first detection range, among the multiple first dividing lines formed by dividing the first detection range at a first angular resolution interval, the position of the first dividing line intersecting with the radiation source in the first image is obtained; and in the second detection range, among the multiple second dividing lines formed by dividing the second detection range at a second angular resolution interval, the position of the second dividing line intersecting with the radiation source in the second image is obtained. The location of the intersection of the first and second bisectors is obtained based on the positions of the first and second bisectors. The location of the intersection is the spatial location of the radioactive source. Based on the number of first rays measured per unit time by the first detection device in the positioning detection area and the number of second rays measured per unit time by the second detection device in the positioning detection area, the proportional relationship between the first distance between the first detection device and the radiation source and the second distance between the second detection device and the radiation source is determined. The corrected spatial position of the radiation source is determined based on the proportional relationship between the first spacing and the second spacing and the relative positional relationship between the first detection device and the second detection device. If the distance between the spatial location of the radioactive source and the corrected spatial location is greater than a threshold, the relative positional relationship between the first detection device and the second detection device is readjusted to redetermine the spatial location of the radioactive source.

2. The spatial positioning method according to claim 1, characterized in that, The first detection device and the second detection device are located in the same plane.

3. The spatial positioning method according to claim 1 or 2, characterized in that, The predetermined angle between the first detection device and the second detection device is 45°.

4. The spatial positioning method according to claim 1, characterized in that, When the distance between the first detection device or the second detection device and the radiation source is L, the first emission count per unit time is N1, and the second emission count per unit time of the radiation source is N2. Then, the first emission count N1, the distance L, and the second emission count N2 satisfy the following relationship: 。 5. The spatial positioning method according to claim 1, characterized in that, When the first distance between the first detection device and the radiation source is L1, the number of third rays measured per unit time in the positioning detection area is N3. When the second distance between the second detection device and the radiation source is L2, the number of fourth rays measured per unit time in the positioning detection area is N4. Then, the number of third rays N3, the number of fourth rays N4, the first distance L1, and the second distance L2 satisfy the following relationship: 。 6. A spatial positioning system for a radioactive source, characterized in that, include: A first detection device and a second detection device are arranged at a predetermined angular interval between them. The first detection device has a first detection range and the second detection device has a second detection range. The area where the first detection range and the second detection range intersect forms a positioning detection area. The first detection device and the second detection device are respectively used to acquire a first image and a second image including a radiation source in the positioning detection area. The calculation unit is configured to: obtain the position of the first bisector line intersecting the radiation source in the first image among multiple first bisector lines formed by equally dividing the first detection range with a first angular resolution interval; obtain the position of the second bisector line intersecting the radiation source in the second image among multiple second bisector lines formed by equally dividing the second detection range with a second angular resolution interval; and obtain the intersection point position of the first bisector line and the second bisector line based on the positions of the first bisector line and the second bisector line, wherein the intersection point position is the spatial position of the radiation source; The calculation unit is further configured to determine the proportional relationship between the first distance between the first detection device and the radiation source and the second distance between the second detection device and the radiation source based on the number of first rays measured by the first detection device per unit time in the positioning detection area and the number of second rays measured by the second detection device per unit time in the positioning detection area. The corrected spatial position of the radiation source is determined based on the proportional relationship between the first spacing and the second spacing and the relative positional relationship between the first detection device and the second detection device. If the distance between the spatial location of the radioactive source and the corrected spatial location is greater than a threshold, the relative positional relationship between the first detection device and the second detection device is readjusted to redetermine the spatial location of the radioactive source.

7. The spatial positioning system according to claim 6, characterized in that, The first detection device or the second detection device further includes a meter, which is used to measure the number of rays from the radioactive source per unit time.

8. The spatial positioning system according to claim 6, characterized in that, The first detection device and the second detection device are either coded gamma cameras or Compton gamma cameras.

Images