Collimator performance test method, apparatus and device, and storage medium

Abstract

The embodiment of the invention provides a collimator performance test method, device and equipment and a storage medium, and the method comprises the steps: obtaining a first projection formed on a probe when a uniform flat plate source irradiates a collimator, the uniform flat plate source is parallel to the surface of a crystal of the probe, and the collimator is arranged between the uniform flat plate source and the probe; and the uniformity information of the collimator is determined based on the first projection, so that the uniformity of the collimator can be measured, and the accuracy of uniformity measurement of the collimator can be improved.

Description

Technical Field

[0001] The present application belongs to the technical field of collimator performance testing, and in particular, relates to a collimator performance testing method, device, equipment and storage medium. Background Art

[0002] For the single photon emission computed tomography (SPECT) system, the collimator is a key component, which determines many system performance indicators. In terms of morphology, it includes: parallel hole collimator, fan beam hole collimator, cone beam hole collimator, pinhole collimator, etc. In terms of energy, there are low energy, medium energy, and high energy collimators. Ideally, the collimator should meet the design requirements and be uniform. However, due to problems such as processing technology and processing accuracy, the actual collimator is not completely uniform. If the collimator is not corrected, the quality of the SPECT reconstructed image will decrease, and in severe cases, artifacts or image distortion may even occur, affecting diagnosis and treatment decisions. Therefore, it is necessary to measure the performance of the collimator to correct the non-uniformity, but the measurement results of the measurement method provided in the relevant technology have large errors. Summary of the invention

[0003] Based on this, the embodiments of the present application provide a collimator performance testing method, device, equipment and storage medium, which can improve the accuracy of the performance measurement of the collimator.

[0004] In a first aspect, an embodiment of the present application provides a collimator performance testing method, comprising:

[0005] Acquire a first projection formed on the probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is disposed between the uniform flat plate source and the probe;

[0006] Uniformity information of the collimator is determined based on the first projection.

[0007] In some embodiments, determining uniformity information of the collimator based on the first projection includes:

[0008] Determine the pixel or crystal area corresponding to each hole based on the first projection;

[0009] The uniformity information of the collimator is determined based on the pixels or crystal areas corresponding to the respective holes, wherein when the number of pixels corresponding to the holes is different or the area of ​​the crystal areas is different or the average count of the projections is different, it is determined that the hole angle and / or the hole diameter and / or the hole wall thickness of the collimator are non-uniform.

[0010] In some embodiments, the method further comprises:

[0011] In the case where the aperture angle and / or aperture diameter and / or aperture wall thickness of the collimator are non-uniform, determining the total number of pixels corresponding to the first projection;

[0012] Obtaining a first calculation result based on the total number of pixels multiplied by the count of the target pixel when the uniform flat panel source irradiates the collimator;

[0013] summing the counts of each pixel when the uniform flat panel source irradiates the collimator to obtain a second calculation result;

[0014] A uniformity correction factor of the target pixel is obtained based on the first calculation result and the second calculation result.

[0015] In a second aspect, a collimator performance testing method is provided, the method comprising:

[0016] Acquire a plurality of second projections formed on the probe when a collimated point source irradiates the collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is in a perpendicular state to the crystal of the probe, the planes where the plurality of positions corresponding to the collimated point source are located are parallel to the surface of the crystal of the probe, and the collimator is arranged between the collimated point source and the probe;

[0017] A hole direction of each hole in the collimator is determined based on the second projection.

[0018] In some embodiments, determining the hole direction of each hole in the collimator based on the second projection comprises:

[0019] determining, based on the second projection, a measured count rate of photons of the target hole in the collimator when the collimated point source is located at various positions;

[0020] The rotation angle of the target hole along the X-axis and the rotation angle of the target hole along the Y-axis are determined based on the theoretical count rates corresponding to each position and the measured count rates.

[0021] In some embodiments, determining the rotation angle of the target hole along the X-axis and the rotation angle of the target hole along the Y-axis based on the theoretical count rate corresponding to each position and the measured count rate includes:

[0022] Determine the loss function based on the theoretical count rate corresponding to each position and the measured count rate, wherein the measured count rate has a calculation relationship with the rotation angle of the target hole along the X axis and the rotation angle along the Y axis, and the theoretical count rate has a calculation relationship with the theoretical rotation angle of the target hole along the X axis and the theoretical rotation angle along the Y axis;

[0023] The loss function is minimized to calculate the rotation angle of the target hole along the X-axis and the rotation angle along the Y-axis.

[0024] In some embodiments, the method further comprises:

[0025] Controlling the movement of the collimated point source and / or the probe to allow a plurality of distances to exist between the collimated point source and the crystal of the probe, and collecting third projections corresponding to the respective distances;

[0026] determining a current rotation angle of the crystal based on the third projection;

[0027] The probe is controlled to rotate based on the current rotation angle so that the crystal of the probe is perpendicular to the emission direction of the collimated point source.

[0028] In some embodiments, determining the current rotation angle of the crystal based on the third projection comprises:

[0029] Determine the position of the center of the light spot on the surface at each distance based on the third projection;

[0030] The current rotation angle of the crystal is determined based on the position and the objective function, wherein the objective function includes: minimizing a distance function, wherein the distance function is equal to the sum of calculation functions corresponding to each distance, wherein the calculation function is equal to the square of the difference between the horizontal coordinate of the position corresponding to each distance and the horizontal coordinate of the position corresponding to a preset distance plus the square of the difference between the vertical coordinate of the position corresponding to each distance and the vertical coordinate of the position corresponding to the preset distance.

[0031] In a third aspect, an embodiment of the present application provides a collimator performance testing device, comprising:

[0032] A first acquisition module, used for acquiring a first projection formed on the probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is arranged between the uniform flat plate source and the probe;

[0033] A first determination module is configured to determine uniformity information of the collimator based on the first projection.

[0034] In a fourth aspect, an embodiment of the present application provides a collimator performance testing device, comprising:

[0035] A second acquisition module is used to acquire a plurality of second projections formed on the probe when a collimated point source irradiates the collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is in a perpendicular state to the crystal of the probe, the planes where the plurality of positions corresponding to the collimated point source are located are parallel to the surface of the crystal of the probe, and the collimator is arranged between the collimated point source and the probe;

[0036] The second determination module is used to determine the hole direction of each hole in the collimator based on the second projection.

[0037] In a fifth aspect, an embodiment of the present application provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any of the methods described above when executing the computer program.

[0038] In a sixth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements any of the methods described above.

[0039] In a seventh aspect, an embodiment of the present application provides a computer program product, which, when executed on a terminal device, enables the electronic device to execute any of the methods described above.

[0040] An embodiment of the present application provides a collimator performance testing method, which obtains a first projection formed on a probe when a uniform flat plate source irradiates the collimator, wherein the uniform flat plate source is parallel to the surface of a crystal of the probe, and the collimator is arranged between the uniform flat plate source and the probe; based on the first projection, the uniformity information of the collimator is determined, so that the uniformity of the collimator can be measured, and the accuracy of the uniformity measurement of the collimator can be improved.

[0041] It can be understood that the beneficial effects of the second to seventh aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 A schematic diagram of the implementation flow of a collimator performance testing method provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the positions of a uniform flat plate source, a collimator and a probe during detection provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of a flow chart of a collimator performance testing method provided in an embodiment of the present application;

[0046] Figure 4 A schematic diagram of the structure of a tungsten tank or a lead tank provided in an embodiment of the present application;

[0047] Figure 5 A schematic diagram of the structure of a collimator performance testing system provided in an embodiment of the present application;

[0048] Figure 6 A schematic diagram of the structure of another collimator performance testing system provided in an embodiment of the present application;

[0049] Figure 7 A schematic diagram of a collimator performance test provided in an embodiment of the present application;

[0050] Figure 8 A schematic diagram of a test when there is a problem with the hole direction of a collimator provided in an embodiment of the present application;

[0051] Fig. 9 A schematic diagram of a crystal surface deflection provided in an embodiment of the present application;

[0052] Fig.10 A schematic diagram for comparing projections in which an emission direction is perpendicular to a crystal surface and an emission direction is not perpendicular to a crystal surface provided in an embodiment of the present application;

[0053] Fig.11 A schematic diagram of the structure of a collimator performance testing device provided in an embodiment of the present application;

[0054] Fig.12 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0055] In the drawings, the same reference numerals are used for the same components, and the drawings are not drawn to scale. DETAILED DESCRIPTION

[0056] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0057] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0058] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0059] As used in the specification of this application and the appended claims, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting" depending on the context. Similarly, the phrases "if it is determined" or "if it is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce detected" or "in response to detecting" depending on the context.

[0060] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0061] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the phrases "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. appearing in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways.

[0062] Based on the technical problems of the related technology, the embodiments of the present application provide a method for determining test information that can be applied to electronic devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPC), netbooks, personal digital assistants (PDA), etc. The embodiments of the present application do not impose any restrictions on the specific types of electronic devices.

[0063] The present application embodiment provides a collimator performance testing method. Figure 1A schematic diagram of the implementation flow of a collimator performance testing method provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes:

[0064] Step S101 , obtaining a first projection formed on a probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is disposed between the uniform flat plate source and the probe.

[0065] In the embodiment of the present application, a uniform plane source is a radiation source characterized by uniformly distributing radiation (such as X-rays, gamma rays, etc.) on a flat surface. The uniform plane source can provide consistent radiation intensity.

[0066] In some embodiments, a linear radiation source may be moved back and forth to provide the effect of a uniform flat plate source. In some embodiments, a point source may be moved in a zigzag manner to provide the effect of a uniform flat plate source.

[0067] In an embodiment of the present application, the probe is used to detect the first projection. A collimator is an optical device used to limit the directionality of a radiation beam to reduce scattering and unnecessary rays. The collimator may be a parallel hole collimator. In some embodiments, the collimator may also be a fan beam hole collimator, a cone beam hole collimator, a pinhole collimator, etc.

[0068] In the embodiment of the present application, the probe can be arranged on a rack, and the position of the probe can be moved by controlling the movement of the rack. The uniform flat plate source can be arranged on a mechanical arm, and the movement of the uniform flat plate source can be controlled by controlling the mechanical arm. The distance between the uniform flat plate source and the probe can be adjusted by controlling the movement of the mechanical arm or the movement of the rack. The first projection is a projection image.

[0069] Figure 2 A schematic diagram of the positions of a uniform flat plate source, a collimator and a probe during detection provided in an embodiment of the present application, such as Figure 2 As shown, the uniform flat source 11 is parallel to the surface of the crystal of the probe 12, and the collimator 13 is arranged between the uniform flat source 11 and the probe 12. The rectangular frame represents the hole wall, and the area between the two rectangular frames is the hole. The uniform flat source is close to the collimator, and it can be considered that the distance between the uniform flat source and the collimator is less than the preset distance.

[0070] Step S102: determining uniformity information of the collimator based on the first projection.

[0071] In the embodiment of the present application, the uniformity information includes: the non-uniformity of the hole angle and the hole wall thickness, and the uniformity of the hole angle and the hole wall thickness.

[0072] In the embodiment of the present application, the hole direction, hole angle, and hole wall thickness of the ideal collimator are consistent everywhere, and its response to the uniform flat plate source is consistent everywhere, that is, the projection is uniform. For the collimator actually produced, the hole direction, hole angle, and hole wall thickness may not be uniform. The uniformity information of the collimator can be reflected by using the first projection.

[0073] An embodiment of the present application provides a collimator performance testing method, which obtains a first projection formed on a probe when a uniform flat plate source irradiates the collimator, wherein the uniform flat plate source is parallel to the surface of a crystal of the probe, and the collimator is arranged between the uniform flat plate source and the probe; based on the first projection, the uniformity information of the collimator is determined, so that the uniformity of the collimator can be measured, and the accuracy of the uniformity measurement of the collimator can be improved.

[0074] In some embodiments, step S102 may be implemented by the following steps:

[0075] Step S1021: determining pixels or crystal regions corresponding to each hole based on the first projection.

[0076] In the embodiments of the present application, image processing techniques (such as edge detection) can be used to identify holes in an image, and algorithms (such as Canny edge detection, threshold segmentation, etc.) can be used to distinguish between holes and non-hole areas. After each hole is determined, the pixel or crystal area corresponding to each hole can be determined.

[0077] Step S1022, determining the uniformity information of the collimator based on the pixels or crystal areas corresponding to the respective holes, wherein when there is a difference in the number of pixels corresponding to the holes or the area of ​​the crystal areas or the difference in the average count of the projections, it is determined that the hole angle and / or the aperture and / or the hole wall thickness of the collimator are non-uniform.

[0078] In the embodiments of the present application, the hole angle refers to the opening angle of the hole. The hole wall thickness refers to the thickness of each hole in the collimator. The aperture refers to the inner diameter of each hole in the collimator.

[0079] In the embodiment of the present application, the number of pixels corresponding to each hole can be counted, and then the number of pixels of each hole can be compared with other holes. If the corresponding numbers of pixels of different holes are significantly different, it indicates that there is a uniformity problem in the collimator. The number of pixels corresponding to the hole walls can be compared. If the corresponding numbers of pixels of different hole walls are significantly different, it indicates that there is a uniformity problem in the collimator. Similarly, the area of ​​the crystal region corresponding to each hole can be compared. If the area of ​​the crystal region of different holes is significantly different, it indicates that there is a uniformity problem in the collimator. The area of ​​the crystal region corresponding to the hole walls can be compared. If the area of ​​the crystal region of different hole walls is significantly different, it indicates that there is a uniformity problem in the collimator.

[0080] The method provided in the embodiment of the present application determines the pixels or crystal areas corresponding to each hole based on the first projection; determines the uniformity information of the collimator based on the pixels or crystal areas corresponding to each hole, wherein, in the case where the number of pixels corresponding to the holes is different or the area of ​​the crystal areas is different or the average count of the projections is different, it is determined that the hole angle and / or aperture and / or hole wall thickness of the collimator are uneven, thereby enabling the evaluation of the uniformity of the collimator.

[0081] In some embodiments, after step S102, the method further includes:

[0082] Step S103, when the aperture angle and / or aperture diameter and / or aperture wall thickness of the collimator are uneven, determining the total number of pixels corresponding to the first projection.

[0083] In the embodiment of the present application, when the aperture angle and / or the aperture wall thickness of the collimator are uneven, correction is required.

[0084] In the embodiment of the present application, the image of the first projection may be analyzed to determine the total number of pixels corresponding to the first projection. Exemplarily, the total number of pixels may be represented by N.

[0085] Step S104 , obtaining a first calculation result based on multiplying the total number of pixels by the count of the target pixel when the uniform flat panel source irradiates the collimator.

[0086] In the embodiment of the present application, the target pixel may be any pixel. Taking the target pixel as the i-th pixel as an example, the count of the target pixel when the uniform flat source irradiates the collimator can be expressed as c i The first calculation result can be expressed as Nc i .

[0087] Step S105 , summing the counts of each pixel when the uniform flat panel source irradiates the collimator to obtain a second calculation result.

[0088] In the embodiment of the present application, the calculation formula of the second calculation result can be expressed as:

[0089]

[0090] Step S106: obtaining a uniformity correction factor of the target pixel based on the first calculation result and the second calculation result.

[0091] In the embodiment of the present application, the uniformity correction factor of the target pixel is obtained by dividing the first calculation result by the second calculation result.

[0092] In the present application embodiment, f irepresents the uniformity correction factor of the target pixel i, then the uniformity correction factor of the target pixel i obtained by dividing the first calculation result by the second calculation result can be expressed by the following formula:

[0093]

[0094] In the embodiment of the present application, the uniformity correction factor can be used to further adjust the imaging system or correct the image data, thereby improving the quality and accuracy of the final image. This process can help correct the brightness non-uniformity caused by the manufacturing error of the collimator in practical applications, and ensure the consistency of quantitative analysis and response during the radiation transmission process.

[0095] Based on the technical problems of the related technology, the embodiments of the present application further provide a method for determining test information that can be applied to electronic devices such as mobile phones, tablet computers, wearable devices, vehicle-mounted devices, augmented reality (AR) / virtual reality (VR) devices, laptops, ultra-mobile personal computers (UMPC), netbooks, personal digital assistants (PDA), etc. The embodiments of the present application do not impose any restrictions on the specific types of electronic devices.

[0096] The present application embodiment provides a collimator performance testing method. Figure 3 A schematic diagram of a flow chart of a collimator performance testing method provided in an embodiment of the present application, such as Figure 3 As shown, the method includes:

[0097] Step S201, obtaining a plurality of second projections formed on the probe when a collimated point source irradiates a collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, an emission direction of the collimated point source is perpendicular to a crystal surface of the probe, a plane where a plurality of positions corresponding to the collimated point source are located is parallel to the crystal surface of the probe, and the collimator is disposed between the collimated point source and the probe.

[0098] In the embodiment of the present application, the collimated point source may be a tungsten can or a lead can. Figure 4 A schematic diagram of the structure of a tungsten tank or a lead tank provided in an embodiment of the present application is shown in FIG. Figure 4 As shown, the structure of the lead can is made of tungsten or lead, and a radioactive source is placed in the tungsten can or the lead can. Due to the blocking of gamma rays by the surrounding tungsten or lead, gamma photons can only be emitted in the direction of the arrow, which is the emission direction of the collimated point source.

[0099] In some embodiments, the collimated point source can be placed on a three-dimensional translation stage. Figure 5 A schematic diagram of the structure of a collimator performance test system provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, the collimator performance test system includes: a three-dimensional translation stage, the three-dimensional translation stage includes: a base 21, a first mechanical arm 22 and a second mechanical arm 23, the first mechanical arm 22 is arranged on the base 21, the second mechanical arm 23 is arranged on the first mechanical arm 22, the second mechanical arm is used to install the collimation point source, the first mechanical arm 22 can drive the second mechanical arm 23 to move up and down, and the second mechanical arm 23 can drive the collimation point source 24 to move left and right. In the embodiment of the present application, the detection device includes: a probe and a frame, and the probe 25 is arranged on the frame 26. There can be two or more probes, which are arranged on the frame.

[0100] In the embodiment of the present application, the collimated point source can be driven to move by the three-dimensional translation stage, so that the position of the collimated point source can be accurately controlled. The probe can also be driven to move by the rack.

[0101] In some embodiments, Figure 6 A structural diagram of another collimator performance testing system provided in an embodiment of the present application is shown in FIG. Figure 6 As shown, the collimated point source 24 can be set on a bed 41, the bed 41 can be set on a base 42, and the probe 25 can be set on a rack 26. The bed length direction can be the Z axis, the vertical direction can be the Y axis, and the horizontal direction can be the X axis. The bed 41 can move horizontally, and the rack 26 can control the probe 25 to move vertically. The collimated point source can be driven to move horizontally by the bed 41, and the probe can be controlled to move vertically up and down by the rack, so as to achieve precise control of the positions of the collimated point source and the probe.

[0102] In the embodiment of the present application, the collimator can be placed between the collimated point source and the probe to ensure that the relative position between the collimated point source and the probe remains unchanged. The position of the collimated point source can be adjusted in sequence, and the second projection formed on the probe after the collimated source irradiates the collimator at each position is recorded.

[0103] Figure 7 A schematic diagram of a collimator performance test provided in an embodiment of the present application, such as Figure 7 As shown, the arrow indicates the moving direction of the collimated point source, so that multiple second projections are formed on the probe when the collimator is irradiated at multiple positions. Figure 8 This is a schematic diagram of a test when there is a problem with the hole direction of a collimator provided in an embodiment of the present application, and multiple second projections are formed on the probe.

[0104] Step S202: determining the hole direction of each hole in the collimator based on the second projection.

[0105] In the embodiment of the present application, the hole direction may include: the rotation angle of the hole along the X-axis and the rotation angle of the hole along the Y-axis.

[0106] In the embodiment of the present application, step S202 can be implemented by the following steps:

[0107] Step S2021, determining the measured photon count rate of the target hole in the collimator when the collimated point source is located at various positions based on the second projection.

[0108] In the embodiment of the present application, at each position, the count of photons passing through the collimator of each target hole can be recorded, and multiple measurements are performed at each position to obtain a stable measured count rate. The measured count rate can be expressed as c m .

[0109] Step S2022, determining a rotation angle of the target hole along the X-axis and a rotation angle of the target hole along the Y-axis based on the theoretical count rates corresponding to each position and the measured count rates.

[0110] In the embodiment of the present application, the target hole may be the kth hole, and the theoretical count rate has a calculation relationship with the rotation angle along the X-axis and the rotation angle along the Y-axis. The theoretical count rate can be expressed as: c t =g j (roll k ,pitch k );

[0111] The rotation angle of the kth hole direction along the X-axis is rollk, and the rotation angle along the Y-axis is pitchk.

[0112] In an embodiment of the present application, a loss function can be determined based on the theoretical counting rate corresponding to each position and the measured counting rate, wherein the measured counting rate has a calculation relationship with the rotation angle of the target hole along the X-axis and the rotation angle along the Y-axis, and the theoretical counting rate has a calculation relationship with the theoretical rotation angle of the target hole along the X-axis and the theoretical rotation angle along the Y-axis; the loss function is minimized to calculate the rotation angle of the target hole along the X-axis and the rotation angle along the Y-axis.

[0113] In the embodiment of the present application, the loss function can be expressed as: Where J is the total number of positions.

[0114] In the embodiment of the present application, by minimizing E k You can get roll k and pitch k .

[0115] In the present application embodiment, the calculation roll k and pitch k The formula can be expressed as:

[0116] (roll k ,pitch k ) = argmin(E k ).

[0117] In the embodiment of the present application, when minimizing the loss function, an optimization algorithm can be used for calculation. The optimization algorithm may include: gradient descent method, Newton method or other nonlinear optimization methods, and the loss function is minimized by the optimization algorithm.

[0118] The method provided in an embodiment of the present application obtains multiple second projections formed on the probe when a collimated point source irradiates a collimator at multiple positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is perpendicular to the crystal of the probe, the planes where the multiple positions corresponding to the collimated point source are located are parallel to the surface of the crystal of the probe, and the collimator is arranged between the collimated point source and the probe; the hole direction of each hole in the collimator is determined based on the second projection, thereby improving the accuracy of the hole direction measurement of the collimator.

[0119] In some embodiments, before step S201, the method further includes:

[0120] Step S2011, controlling the movement of the collimated point source and / or the probe so that there are multiple distances between the collimated point source and the crystal of the probe, and collecting third projections corresponding to each distance.

[0121] In the embodiment of the present application, the movement of the collimated point source and / or the probe can be controlled by controlling a three-dimensional translation stage or a rack.

[0122] In the embodiment of the present application, it can be assumed that the emission direction of the collimated point source is vertically downward, and the rotation angle of the crystal surface along the X-axis is roll, the rotation angle along the Y-axis is pitch, and the rotation angle along the Z-axis is yaw. Fig. 9 A schematic diagram of a crystal surface deflection provided in an embodiment of the present application, such as Fig. 9 As shown, in order to make the emission direction of the collimated point source perpendicular to the plane of the crystal, it is necessary to calculate the rotation angle of the crystal surface along the X-axis as roll, the rotation angle along the Y-axis as pitch, and the rotation angle along the Z-axis as yaw to adjust the crystal.

[0123] Step S2012: determining a current rotation angle of the crystal based on the third projection.

[0124] In the embodiment of the present application, the corresponding third projection can be collected at each position. Fig.10A schematic diagram for comparing projections in which an emission direction is perpendicular to the crystal surface and an emission direction is not perpendicular to the crystal surface provided in an embodiment of the present application, such as Fig.10 As shown in FIG. 1 , when the emission direction of the collimated point source is perpendicular to the surface of the crystal, the light spot is a perfect circle, while when the emission direction of the collimated point source is not perpendicular to the surface of the crystal, the light spot is not a perfect circle. This principle can be used to calculate the current selection angle of the crystal surface.

[0125] In an embodiment of the present application, determining the current rotation angle of the crystal based on the third projection includes:

[0126] Step S1, determining the shape of the center of the light spot on the surface at various distances based on the third projection.

[0127] In the embodiment of the present application, through the vertical image, ai-bi-ci-di represents the projection spot Si at the i-th height, and the collimated point source emission angle is θ. Using the geometric relationship, it can be known that when the distance between the point source and the detector surface is hi, the position of the spot center Oi at the detector surface coordinate is (xi, yi), Si is:

[0128] x i =g x (h i ,θ,roll,pitch,yaw);

[0129] y i =g y (h i ,θ,roll,pitch,yaw);

[0130] s i =s i (h i ,θ,roll,pitch,yaw)

[0131] Specifically, a series of points can be taken on the perimeter of the spot, such as Fig. 9 and Fig.10 The light spot shape is characterized by a1-b1-c1-d1.

[0132] After measuring several sets of data, a series of spot shapes can be obtained.

[0133] Step S2, determining the current rotation angle of the crystal based on the position and the objective function, wherein the objective function includes: minimizing a distance function, wherein the distance function is equal to the sum of calculation functions corresponding to each distance, wherein the calculation function is equal to the square of the difference between the horizontal coordinate of the position corresponding to each distance and the horizontal coordinate of the position corresponding to a preset distance plus the square of the difference between the vertical coordinate of the position corresponding to each distance and the vertical coordinate of the position corresponding to the preset distance.

[0134] In the embodiment of the present application, the objective function can be expressed as:

[0135]

[0136] In the above formula, xi and yi may be the preset coordinates of a point on the circumference of the light spot, and xmi and ymi may be the measured coordinates of a point on the circumference of the light spot.

[0137] In the embodiment of the present application, D can be minimized to obtain roll, pitch and yaw.

[0138] In the embodiment of the present application, the minimization objective function can be expressed as: (roll, pitch, yaw) = argmin (D);

[0139] Step S2013: Control the rotation of the probe based on the current rotation angle so that the crystal of the probe is perpendicular to the emission direction of the collimated point source.

[0140] In the embodiment of the present application, after the current selection angle is determined, the probe can be rotated -roll, -pitch, -yaw to make the emission direction of the point source perpendicular to the crystal surface.

[0141] According to the aforementioned embodiments, the embodiments of the present application provide a collimator performance testing device, and the modules included in the device, as well as the units included in the modules, can be implemented by a processor in a computer device; of course, they can also be implemented by a specific logic circuit; in the implementation process, the processor can be a central processing unit (CPU, Central Processing Unit), a microprocessor (MPU, Microprocessor Unit), a digital signal processor (DSP, Digital Signal Processing) or a field programmable gate array (FPGA, Field Programmable Gate Array), etc.

[0142] The present application embodiment provides a collimator performance testing device, Fig.11 A schematic diagram of the structure of a collimator performance testing device provided in an embodiment of the present application is shown in FIG. Fig.11 As shown, the collimator performance testing device 1100 includes:

[0143] A first acquisition module 1101 is used to acquire a first projection formed on the probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is disposed between the uniform flat plate source and the probe;

[0144] The first determination module 1102 is configured to determine uniformity information of the collimator based on the first projection.

[0145] In some embodiments, the first determining module includes:

[0146] A first determining unit, configured to determine pixels corresponding to each hole based on the first projection;

[0147] The second determination unit is used to determine the uniformity information of the collimator based on the pixels corresponding to the holes, wherein when there are different numbers of pixels corresponding to the holes, it is determined that the hole angle and / or hole wall thickness of the collimator are uneven.

[0148] In some embodiments, the collimator performance testing device further comprises:

[0149] A third determination module is used to determine the total number of pixels corresponding to the first projection when the aperture angle and / or the aperture wall thickness of the collimator are uneven;

[0150] A first calculation module, configured to obtain a first calculation result based on the total number of pixels multiplied by the count of the target pixel when the uniform flat panel source irradiates the collimator;

[0151] A second calculation mode is used to sum the counts of each pixel when the uniform flat panel source irradiates the collimator to obtain a second calculation result;

[0152] The third calculation module is used to divide the first calculation result by the second calculation result to obtain a uniformity correction factor of the target pixel.

[0153] The present application embodiment provides another collimator performance testing device, comprising:

[0154] A second acquisition module is used to acquire a plurality of second projections formed on the probe when a collimated point source irradiates the collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is in a perpendicular state to the crystal of the probe, the planes where the plurality of positions corresponding to the collimated point source are located are parallel to the surface of the crystal of the probe, and the collimator is arranged between the collimated point source and the probe;

[0155] The second determination module is used to determine the hole direction of each hole in the collimator based on the second projection.

[0156] In some embodiments, the second determining module includes:

[0157] a third determining unit, configured to determine, based on the second projection, a measured count rate of photons of the target hole in the collimator when the collimated point source is located at various positions;

[0158] The fourth determination unit is used to determine the rotation angle of the target hole along the X-axis and the rotation angle of the target hole along the Y-axis based on the theoretical counting rate corresponding to each position and the measured counting rate.

[0159] In some embodiments, the fourth determining unit includes:

[0160] A first determination subunit is used to determine a loss function based on a theoretical count rate corresponding to each position and the measured count rate, wherein the measured count rate has a calculation relationship with a rotation angle of the target hole along the X axis and a rotation angle along the Y axis, and the theoretical count rate has a calculation relationship with a theoretical rotation angle of the target hole along the X axis and a theoretical rotation angle along the Y axis;

[0161] The second determination subunit is used to minimize the loss function to calculate the rotation angle of the target hole along the X-axis and the rotation angle along the Y-axis.

[0162] In some embodiments, the collimator performance testing device further comprises:

[0163] A first control module is used to control the movement of the collimated point source and / or the probe so that there are multiple distances between the collimated point source and the crystal of the probe, and to collect third projections corresponding to each distance;

[0164] a fourth determination module, configured to determine a current rotation angle of the crystal based on the third projection;

[0165] The second control module is used to control the rotation of the probe based on the current rotation angle so that the crystal of the probe is perpendicular to the emission direction of the collimated point source.

[0166] In some embodiments, the fourth determining module includes:

[0167] A fifth determining unit, configured to determine the position of the center of the light spot on the surface at each distance based on the third projection;

[0168] A sixth determination unit is used to determine the current rotation angle of the crystal based on the position and an objective function, wherein the objective function includes: minimizing a distance function, wherein the distance function is equal to the sum of calculation functions corresponding to each distance, wherein the calculation function is equal to the square of the difference between the horizontal coordinate of the position corresponding to each distance and the horizontal coordinate of the position corresponding to a preset distance plus the square of the difference between the vertical coordinate of the position corresponding to each distance and the vertical coordinate of the position corresponding to the preset distance.

[0169] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0170] In addition, the collimator performance test device may be a software unit, a hardware unit, or a unit combining software and hardware, or may be integrated into the electronic device as an independent pendant, or may exist as an independent terminal device.

[0171] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0172] Fig.12 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application, such as Fig.12 As shown, the electronic device 3 of this embodiment may include: at least one processor 30 ( Fig.12 Only one processor 30 is shown in the figure), a memory 31, and a computer program 32 stored in the memory 31 and executable on at least one processor 30. When the processor 30 executes the computer program 32, the steps in any of the above-mentioned method embodiments are implemented, for example Figure 1 Step S101 to step S102 in the embodiment shown, or Figure 3 Steps S201 to S202 in the illustrated embodiment, or when the processor 30 executes the computer program 32, implement the functions of the modules / units in the above-mentioned system embodiments.

[0173] Exemplarily, the computer program 32 may be divided into one or more modules / units, one or more modules / units are stored in the memory 31, and are executed by the processor 30 to complete the present application. One or more modules / units may be a series of computer program 32 instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution process of the computer program 32 in the electronic device 3.

[0174] The embodiment of the present application further provides a computer-readable storage medium, which stores a computer program 32. When the computer program 32 is executed by the processor 30, the steps in the above-mentioned method embodiments can be implemented.

[0175] An embodiment of the present application provides a computer program product. When the computer program product runs on an electronic device, the electronic device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0176] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. According to this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program 32, and the computer program 32 can be stored in a computer-readable storage medium, and the computer program 32 can implement the steps of the above-mentioned various method embodiments when executed by the processor 30. Among them, the computer program 32 includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device capable of carrying the computer program code to the terminal, a recording medium, a computer memory, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0177] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0178] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0179] In the embodiments provided in the present application, it should be understood that the disclosed devices / network equipment and methods can be implemented in other ways. For example, the device / network equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0180] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0181] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A collimator performance testing method, characterized in that: include: Acquire a first projection formed on the probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is disposed between the uniform flat plate source and the probe; Uniformity information of the collimator is determined based on the first projection.

2. The method according to claim 1, characterized in that The determining the uniformity information of the collimator based on the first projection comprises: Determine the pixel or crystal area corresponding to each hole based on the first projection; The uniformity information of the collimator is determined based on the pixels or crystal areas corresponding to the respective holes, wherein when the number of pixels corresponding to the holes is different or the area of ​​the crystal areas is different or the average count of the projections is different, it is determined that the hole angle and / or the hole diameter and / or the hole wall thickness of the collimator are non-uniform.

3. The method according to claim 2, characterized in that The method further comprises: In the case where the aperture angle and / or aperture diameter and / or aperture wall thickness of the collimator are non-uniform, determining the total number of pixels corresponding to the first projection; Obtaining a first calculation result based on the total number of pixels multiplied by the count of the target pixel when the uniform flat panel source irradiates the collimator; summing the counts of each pixel when the uniform flat panel source irradiates the collimator to obtain a second calculation result; A uniformity correction factor of the target pixel is obtained based on the first calculation result and the second calculation result.

4. A collimator performance testing method, characterized in that: The method comprises: Acquire a plurality of second projections formed on the probe when a collimated point source irradiates the collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is perpendicular to the crystal surface of the probe, the planes where the plurality of positions corresponding to the collimated point source are located are parallel to the crystal surface of the probe, and the collimator is disposed between the collimated point source and the probe; A hole direction of each hole in the collimator is determined based on the second projection.

5. The method according to claim 4, characterized in that The determining the hole direction of each hole in the collimator based on the second projection comprises: determining, based on the second projection, a measured count rate of photons of the target hole in the collimator when the collimated point source is located at various positions; The rotation angle of the target hole along the X-axis and the rotation angle of the target hole along the Y-axis are determined based on the theoretical count rates corresponding to each position and the measured count rates.

6. The method according to claim 5, characterized in that The step of determining the rotation angle of the target hole along the X-axis and the rotation angle of the target hole along the Y-axis based on the theoretical count rate corresponding to each position and the measured count rate includes: Determine the loss function based on the theoretical count rate corresponding to each position and the measured count rate, wherein the measured count rate has a calculation relationship with the rotation angle of the target hole along the X axis and the rotation angle along the Y axis, and the theoretical count rate has a calculation relationship with the theoretical rotation angle of the target hole along the X axis and the theoretical rotation angle along the Y axis; The loss function is minimized to calculate the rotation angle of the target hole along the X-axis and the rotation angle along the Y-axis.

7. The method according to claim 4, characterized in that The method further comprises: Controlling the movement of the collimated point source and / or the probe to allow a plurality of distances to exist between the collimated point source and the crystal of the probe, and collecting third projections corresponding to the respective distances; determining a current rotation angle of the crystal based on the third projection; The probe is controlled to rotate based on the current rotation angle so that the crystal of the probe is perpendicular to the emission direction of the collimated point source.

8. The method according to claim 7, characterized in that The determining the current rotation angle of the crystal based on the third projection comprises: Determine the position of the center of the light spot on the surface at each distance based on the third projection; The current rotation angle of the crystal is determined based on the position and the objective function, wherein the objective function includes: minimizing a distance function, wherein the distance function is equal to the sum of calculation functions corresponding to each distance, wherein the calculation function is equal to the square of the difference between the horizontal coordinate of the position corresponding to each distance and the horizontal coordinate of the position corresponding to a preset distance plus the square of the difference between the vertical coordinate of the position corresponding to each distance and the vertical coordinate of the position corresponding to the preset distance.

9. A collimator performance testing device, characterized in that: include: A first acquisition module, used for acquiring a first projection formed on the probe when a uniform flat plate source irradiates a collimator, wherein the uniform flat plate source is parallel to a surface of a crystal of the probe, and the collimator is arranged between the uniform flat plate source and the probe; A first determination module is configured to determine uniformity information of the collimator based on the first projection.

10. A collimator performance testing device, characterized in that: include: A second acquisition module is used to acquire a plurality of second projections formed on the probe when a collimated point source irradiates the collimator at a plurality of positions, wherein when the collimated point source irradiates the collimator, the emission direction of the collimated point source is in a perpendicular state to the crystal of the probe, the planes where the plurality of positions corresponding to the collimated point source are located are parallel to the surface of the crystal of the probe, and the collimator is arranged between the collimated point source and the probe; The second determination module is used to determine the hole direction of each hole in the collimator based on the second projection.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 8 is implemented.

12. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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