Deviation obtaining method and device of single photon emission computed tomography system

Abstract

The invention relates to a deviation acquisition method and device of a single photon emission computed tomography system, equipment and a medium, which can improve the deviation estimation accuracy of the system. The method comprises the following steps: controlling a target object to move to a first target position through a translation stage, and determining an actual detection position of the target object recognized by a system probe under a current pose; obtaining a first expected pose deviation; the first expected pose deviation represents the deviation between the expected pose and the current pose of the system probe; determining an expected detection position of the target object according to the first target position and the first expected pose deviation, and obtaining a first position difference between the expected detection position and the actual detection position; and according to the first position difference corresponding to each first expected pose deviation, determining the actual pose deviation between the expected pose and the current pose of the system probe.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nuclear medicine, and in particular to a method and device for acquiring a deviation of a single-photon emission computed tomography (SPECT) system, a computer device, a storage medium, and a computer program product. BACKGROUND

[0002] Single-photon emission computed tomography (SPECT) technology is a mature imaging technology in the field of nuclear medicine today and has been widely used in clinical detection. A probe is provided in a SPECT system. In order to obtain reliable detection results, the position, direction, and transformation of the probe during scanning need to be accurately known. However, due to various factors, the probe often deviates from the expected position, affecting the reliability of the detection results.

[0003] In the related art, the deviation between the actual position and the expected position of the probe can be estimated and corrected by measuring the radioactive source. However, the accuracy of the system deviation obtained by the above method still needs to be improved. SUMMARY

[0004] Therefore, it is necessary to provide a method and device for acquiring a deviation of a single-photon emission computed tomography (SPECT) system, a computer device, a computer readable storage medium, and a computer program product, which can improve the accuracy of system deviation estimation.

[0005] In a first aspect, the present application provides a method for acquiring a deviation of a single-photon emission computed tomography (SPECT) system, comprising:

[0006] controlling a target object to move to a first target position by a translation stage, and determining an actual detection position of the target object recognized by a system probe in a current pose;

[0007] acquiring a first expected pose deviation; the first expected pose deviation represents a deviation between an expected pose and the current pose of the system probe;

[0008] determining an expected detection position of the target object according to the first target position and the first expected pose deviation, and acquiring a first position difference between the expected detection position and the actual detection position;

[0009] determining an actual pose deviation between the expected pose and the current pose of the system probe according to the first position difference corresponding to each of the first expected pose deviations.

[0010] In one embodiment, the determination of the actual detection position of the target object recognized by the system probe in the current pose comprises:

[0011] determining a projection of the target object on a detection surface corresponding to the system probe when the target object is at the first target position; the probe plane is the detection surface corresponding to the system probe at the current pose;

[0012] determining an actual detection position of the target object recognized by the system probe according to a projection center of the projection on the detection surface.

[0013] In one of the embodiments, after the actual pose difference between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each of the first expected pose deviations, the method further comprises:

[0014] adjusting the current pose of the system probe, and re-determining the actual pose difference between the expected pose and the current pose of the system probe after the pose adjustment, to obtain the actual pose difference of the system probe at each pose.

[0015] In one of the embodiments, after the actual pose difference of the system probe at each pose is obtained, the method further comprises:

[0016] moving the target object to a second target position by the translation table;

[0017] determining an actual position of the target object in the system coordinate system according to the actual pose difference of the system probe at each pose and the scan data collected by the system probe for the target object;

[0018] obtaining a second expected pose deviation; the second expected pose deviation represents a deviation between the system coordinate system and the translation table coordinate system;

[0019] determining a predicted position of the target object in the system coordinate system according to the second target position and the second expected pose deviation, and obtaining a second position difference between the predicted position and the actual position;

[0020] determining an actual pose deviation between the system coordinate system and the translation table coordinate according to the second position difference corresponding to each of the second expected pose deviations.

[0021] In one of the embodiments, the determining of the actual position of the target object in the system coordinate system according to the actual pose difference of the system probe at each pose and the scan data collected by the system probe for the target object comprises:

[0022] obtaining the scan data collected by the system probe for the target object;

[0023] According to the actual position difference of the system probe at each pose, the scanning data is corrected, and the corrected scanning data is used for image reconstruction to obtain a reconstructed image.

[0024] According to the projection center of the target object on the reconstructed image, an actual position of the target object in a system coordinate system is determined.

[0025] In one of the embodiments, the actual detection position and the expected detection position include actual detection positions and expected detection positions respectively acquired when the target object is at a plurality of first target positions.

[0026] The first position difference between the expected detection position and the actual detection position is obtained.

[0027] For each first target position, a distance between the corresponding expected detection position and the actual detection position is determined.

[0028] According to the distance of the target object at each first target position, a first position difference between the expected detection position and the actual detection position is determined.

[0029] In one of the embodiments, the target object includes a radioactive source arranged on a mechanical arm of a translation table.

[0030] The target object is moved to the first target position by the translation table, including:

[0031] The translation table is sent a radioactive source movement instruction, and the radioactive source movement instruction is used to instruct the translation table to control the movement of the mechanical arm according to displacement control information carried by the radioactive source movement instruction, so that the radioactive source moves to the corresponding first target position.

[0032] In a second aspect, the application further provides a deviation acquisition device of a single photon emission computed tomography system, including:

[0033] An actual detection position determination module is configured to determine an actual detection position of the target object recognized by the system probe at a current pose by moving the target object to a first target position by a translation table.

[0034] A first deviation prediction module is configured to obtain a first expected pose deviation; the first expected pose deviation represents a deviation between an expected pose and a current pose of the system probe.

[0035] An expected detection position determination module is configured to determine an expected detection position of the target object according to the first target position and the first expected pose deviation, and obtain a first position difference between the expected detection position and the actual detection position.

[0036] The probe pose deviation determination module is configured to determine an actual pose deviation between the expected pose and the current pose of the system probe according to the first position difference corresponding to each of the first expected pose deviations.

[0037] In a third aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0038] The actual detection position of the target object is determined by moving the target object to the first target position through the translation table and by the system probe in the current pose;

[0039] An expected pose deviation of the system probe is obtained, wherein the expected pose deviation represents a deviation between an expected pose and a current pose of the system probe;

[0040] An expected detection position of the target object is determined according to the first target position and the expected pose deviation, and a first position difference between the expected detection position and the actual detection position is obtained;

[0041] An actual pose deviation between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each of the first expected pose deviations.

[0042] In a fourth aspect, the present application provides a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to implement the following steps:

[0043] The actual detection position of the target object is determined by moving the target object to the first target position through the translation table and by the system probe in the current pose;

[0044] An expected pose deviation of the system probe is obtained, wherein the expected pose deviation represents a deviation between an expected pose and a current pose of the system probe;

[0045] An expected detection position of the target object is determined according to the first target position and the expected pose deviation, and a first position difference between the expected detection position and the actual detection position is obtained;

[0046] An actual pose deviation between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each of the first expected pose deviations.

[0047] In a fifth aspect, the present application provides a computer program product, comprising a computer program, wherein the computer program is executed by a processor to implement the following steps:

[0048] determine an actual detection position of the target object recognized by the system probe in the current pose by controlling the target object to move to a first target position through a translation table;

[0049] obtain a first expected pose deviation; the first expected pose deviation represents a deviation between an expected pose and the current pose of the system probe;

[0050] determine an expected detection position of the target object according to the first target position and the first expected pose deviation, and obtain a first position difference between the expected detection position and the actual detection position;

[0051] determine an actual pose deviation between the expected pose and the current pose of the system probe according to the first position difference corresponding to each of the first expected pose deviations.

[0052] The deviation obtaining method, device, computer device, storage medium and computer program product of the single photon emission computed tomography system can first control the target object to move to a first target position through a translation table, and then determine an actual detection position of the target object recognized by the system probe in the current pose. Moreover, a first expected pose deviation can be obtained, the first expected pose deviation representing a deviation between an expected pose and the current pose of the system probe. An expected detection position of the target object is determined according to the first target position and the first expected pose deviation, and then a first position difference between the expected detection position and the actual detection position can be obtained. An actual pose deviation between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each of the first expected pose deviations. In this embodiment, the translation table can be used to accurately control the position of the target object, so that the first target position accurately corresponds to the actual position of the target object. Therefore, the difference between the expected detection position and the actual detection position calculated based on the first target position and the first expected pose deviation can accurately represent the deviation between the expected pose and the current pose of the system probe, and the accuracy of deviation estimation and correction is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed in the embodiment or related art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0054] Figure 1 A flowchart of a deviation obtaining method of a single photon emission computed tomography system in one embodiment;

[0055] Figure 2Fig. 1 is a schematic diagram of actual and expected positions of a system probe in an embodiment;

[0056] Figure 3 Fig. 2 is a schematic diagram of a process for determining actual position deviation between a system coordinate system and a translation table coordinate system in an embodiment;

[0057] Figure 4 Fig. 3 is a position diagram of a single photon emission computed tomography system and a translation table system in an embodiment;

[0058] Figure 5 Fig. 4 is a schematic diagram of a process for deviation acquisition of another single photon emission computed tomography system in an embodiment;

[0059] Figure 6 Fig. 5 is a structural block diagram of a deviation acquisition device of a single photon emission computed tomography system in an embodiment;

[0060] Figure 7 Fig. 6 is an internal structure diagram of a computer device in an embodiment;

[0061] Figure 8 Fig. 7 is an internal structure diagram of another computer device in an embodiment. DETAILED DESCRIPTION

[0062] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0063] In order to make those skilled in the art better understand the present application, the related art will be introduced first.

[0064] Single photon emission computed tomography technology, as a mature imaging technology in the field of nuclear medicine today, has been widely used in clinical detection. A probe is provided in a single photon emission computed tomography system (hereinafter referred to as a SPECT system). During detection, the probe will perform different movements to complete scanning of a patient, for example, rotating the probe around the patient. In order to reconstruct the distribution and changes of a radioactive tracer in the patient's body from the scanning data, it is necessary to accurately determine the position, direction and corresponding changes of the probe during scanning. However, in actual application, due to factors such as errors in gantry installation, errors in motion control or the weight of the probe itself, the probe often deviates from the expected position, resulting in a decrease in the quality of the reconstructed image, the appearance of artifacts in the reconstructed image and other situations, which seriously affect the quality of the detection result.

[0065] In the related art, the deviation between the actual position and the expected position of the probe can be estimated and corrected through measurement of the radioactive source. However, due to the geometric accuracy of the radioactive source itself (such as distance or direction error between radioactive sources), it is difficult to obtain an accurate deviation estimation result. In addition, the actual motion state of the probe can also be obtained through external equipment (such as an optical capture method). However, due to the mechanical accuracy and installation error of the probe, there is still an error between the probe shell and the actual detection plane.

[0066] Based on this, the present application provides a deviation acquisition method and device of a single photon emission computed tomography system, a computer device, a storage medium and a computer program product, to at least solve the problem of low accuracy of the SPECT system deviation acquired in the related art.

[0067] In one embodiment, as shown in Figure 1 A deviation acquisition method of a single photon emission computed tomography system is provided. This embodiment is exemplified by the method applied to a SPECT system. It can be understood that the method can also be applied to a server, and can also be applied to a system including a terminal and a server, and can be realized through the interaction of the terminal and the server. In this embodiment, the following steps S101 to S104 are included.

[0068] S101, moving the target object to a first target position through a translation stage to determine the actual detection position of the target object recognized by the system probe in the current pose.

[0069] The translation stage can be understood as a high-precision execution device. In some embodiments, the translation stage can be driven by a stepping motor therein, and can move in at least one of the x-axis direction, the y-axis direction and the z-axis direction, so as to translate the object to a specified position, and realize high-precision micro-movement in any direction (such as movement of nanometers and above).

[0070] The target object can be a radioactive source carrying a radioactive tracer.

[0071] In specific implementations, a translation stage can be provided, which can control the target object to move in at least one of the x-axis direction, the y-axis direction and the z-axis direction. For example, in one embodiment, if the translation stage is a three-dimensional translation stage, the target object can be controlled to move arbitrarily in a three-dimensional space, and if the translation stage is a two-dimensional translation stage, the target object can be controlled to move arbitrarily on a two-dimensional plane.

[0072] In this step, the target object can be moved to a specified position by the translation table, which can be any position in the scanning area of the SPECT system. For the sake of distinction from other positions, this position is also referred to as a first target position. The first target position can be understood as the movement control result of the translation table on the target object, that is, the first target position can be obtained based on the position control information input during the movement control process, and corresponds to the position of the target object in the real world, which can identify the actual position of the target object. By controlling the movement of the target object by the translation table, accurate control of the position of the target object can be achieved, and accurate and reliable position information of the target object can be obtained.

[0073] After the target object is moved to the first target position by the translation table, the system probe can be controlled to detect the target object located at the first target position in the current pose, and the actual detection position of the target object is identified.

[0074] The actual detection position can be understood as the position of the target object in the real world identified by the system probe after independent detection of the translation table, in other words, the actual detection position can be the identification result obtained by the system probe after position identification of the target object located at the first target position.

[0075] In S102, a first expected pose deviation is obtained; the first expected pose deviation represents the deviation between the expected pose of the system probe and the current pose.

[0076] The expected pose of the system probe can also be referred to as an ideal pose, which can be understood as the pose that the user hopes the system probe to reach, for example, the pose of the system probe input by the user in the SPECT system can be taken as the expected pose of the system probe. The current pose of the system probe can also be referred to as the actual pose of the system probe, that is, the pose currently maintained by the system probe in the real world.

[0077] In actual application, the expected pose of the system probe and the current position can have a certain deviation, Figure 2 A schematic diagram of the pose deviation in a two-dimensional plane is shown, for the sake of simplicity, Figure 2 The pose deviation is shown in two-dimensional form, and in actual situation, it is three-dimensional. From Figure 2 It can be seen that the expected pose of the system probe has a certain position deviation and rotation angle deviation relative to the actual pose.

[0078] To this end, in this step, a pose deviation between the expected pose and the current pose of the system probe can be predicted, that is, a difference between the expected pose and the current pose of the system probe is estimated in advance, and one or more expected pose deviations are determined, which can include a translation deviation between the expected pose and the current pose, and a rotation angle deviation between the expected pose and the current pose; for the sake of distinction, the pose deviation can also be referred to as a first expected pose deviation, which can reflect the displacement and / or angular rotation of the expected pose relative to the current pose.

[0079] In S103, an expected detection position of the target object is determined according to the first target position and the first expected pose deviation, and a first position difference between the expected detection position and the actual detection position is obtained.

[0080] Specifically, after the target object is moved to the first target position, a position of the target object recognized by the system probe when the system probe is in the expected pose can be predicted based on the coordinate transformation of the first target position. For example, if the first target position is a position determined with respect to the translational table coordinate system as the reference system, the first target position can be transformed by the conversion relationship between the translational table coordinate system and the system coordinate system corresponding to the SPECT system, and the position conversion result is taken as the position of the target object recognized by the system probe when the system probe is in the current pose. Then, the position of the target object detected by the system probe when the expected pose deviation is considered can be predicted by combining the coordinate conversion result and the first expected pose deviation, which is also referred to as the expected detection position or the predicted position.

[0081] In other words, in this step, the position of the target object recognized by the system probe when the system probe reaches the current pose can be predicted according to the first target position, and then the expected detection position of the target object when the system probe is in the expected pose is obtained by further combining the first expected pose deviation.

[0082] It can be understood that the actual detection position obtained in advance is a position determined according to the detection data of the system probe itself, and the expected detection position is a position calculated according to the first target position and the first expected pose deviation. The actual detection position and the expected detection position are obtained by identifying the same object (i.e., the position of the target object detected by the system probe in the current pose) in different ways. Ideally, the actual detection position and the expected detection position are the same, but in specific implementations, due to different estimation conditions of the first expected pose deviation, the actual detection position and the expected detection position can be different. By comparing the difference between the actual detection position and the expected detection position, whether the first expected pose deviation is accurate can be determined.

[0083] Based on this, after the expected detection position of the target object is determined, the position difference between the expected detection position and the actual detection position can be determined, which is also referred to as the first position difference for the sake of distinction.

[0084] In S104, the actual pose deviation between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each first expected pose deviation.

[0085] Specifically, when the first expected pose deviation is obtained, at least one first expected pose deviation can be obtained, and for each first expected pose deviation, the corresponding first position difference under the first expected pose deviation can be obtained based on step S103. It can be understood that the first position difference is related to the first expected pose deviation, the higher the accuracy of the first expected pose deviation, the smaller the first position difference, and based on this, the actual pose deviation between the expected pose and the current pose of the system probe can be determined according to the first position difference corresponding to each first expected pose deviation.

[0086] In one embodiment, if a plurality of first expected pose deviations Γ1 are obtained in advance, after the first position difference F(Γ1) corresponding to each first expected pose deviation Γ1 is determined, the first position differences F(Γ1) can be compared to determine the first expected pose deviation Γ1 corresponding to the minimum value of F(Γ1), and the first expected pose deviation Γ1 is determined as the actual pose deviation between the expected pose and the current pose of the system probe. For example, the actual pose deviation between the expected pose and the current pose can be determined according to the formula as follows:

[0087]

[0088] wherein Γ + is the estimated actual pose deviation between the expected pose and the current pose, and Γ is the pose deviation, which can be the first expected pose deviation Γ1 or the second expected pose deviation Γ2.

[0089] The deviation acquisition method of the single-photon emission computed tomography system can first control the target object to move to a first target position through the translation table, and then can determine an actual detection position of the target object recognized by the system probe in the current pose. Moreover, a first expected pose deviation can be acquired, the first expected pose deviation representing a deviation between the expected pose and the current pose of the system probe. According to the first target position and the first expected pose deviation, an expected detection position of the target object is determined, and then a first position difference between the expected detection position and the actual detection position can be acquired. According to the first position difference corresponding to each first expected pose deviation, an actual pose deviation between the expected pose and the current pose of the system probe is determined. In this embodiment, the translation table can be used to accurately control the position of the target object, so that the first target position accurately corresponds to the actual position of the target object. Therefore, the difference between the expected detection position and the actual detection position calculated based on the first target position and the first expected pose deviation can accurately represent the deviation between the expected pose and the current pose of the system probe, and the accuracy of deviation estimation and correction is effectively improved.

[0090] In one embodiment, in step S101, determining the actual detection position of the target object recognized by the system probe in the current pose can include the following steps:

[0091] Determining a projection of the target object on a detection surface corresponding to the system probe when the target object is at the first target position; and determining the actual detection position of the target object recognized by the system probe according to a projection center of the projection on the detection surface.

[0092] In this embodiment, the detection surface is the detection surface corresponding to the system probe in the current pose. For example, the detection surface corresponding to the system probe can be a plane, such as a planar probe, or a curved surface, such as a curved surface probe.

[0093] In a specific implementation, when the rays emitted by the target object irradiate on the detection surface of the system probe, a corresponding projection is formed on the detection surface. In this embodiment, when the target object moves to the first target position, the system probe in the current pose can be used to collect scanning data of the target object, and the projection of the target object on the detection surface of the system probe in the current pose is obtained.

[0094] After obtaining the projection of the target object on the detection surface, the projection center can be determined. In one embodiment, for the projection on the detection surface, Gaussian fitting can be performed on the projection in two mutually perpendicular directions, for example, Gaussian fitting can be performed on the projection in the x-axis direction and the y-axis direction corresponding to the detection surface, respectively. According to the peak values of the Gaussian fitting in the two directions, the projection center is determined.

[0095] Then, the actual detection position of the target object recognized by the system probe can be determined according to the projection center, for example, the projection center position corresponding to the projection center can be obtained, and the projection center position is determined as the actual detection position of the target object.

[0096] In this embodiment, the detection surface corresponding to the system probe changes with the change of the system probe pose, and by obtaining the projection center of the target object on the detection surface, the actual detection position recognized by the system probe at the current pose can be quickly and accurately obtained with the detection surface as the reference system.

[0097] In one embodiment, after the actual pose deviation between the expected pose and the current pose of the system probe is determined according to the first position difference corresponding to each first expected pose deviation in step S104, the method can further include the following steps:

[0098] Adjusting the current pose of the system probe, and re-determining the actual pose deviation between the expected pose and the current pose of the system probe after the pose adjustment, to obtain the actual pose deviation of the system probe at each pose.

[0099] In a specific implementation, after the actual pose deviation of the system probe corresponding to the current pose is determined, the current pose of the system probe can be adjusted, for example, the SPECT system can adjust the system probe pose according to the pose adjustment parameter, and rotate the system probe to a new angle. In some embodiments, the pose adjustment of the system probe can be determined according to the pose used by the system probe in the actual detection process, that is, the pose of the system probe can be adjusted to each pose used in the actual detection process.

[0100] After obtaining the new current pose, the actual pose deviation between the expected pose and the current pose of the system probe after the pose adjustment can be re-determined according to steps S101 to S104, so as to obtain the actual pose deviation of the system probe at each pose.

[0101] In this embodiment, by adjusting the pose of the system probe and determining the actual pose deviation again, the actual pose deviation of the system probe at each pose can be obtained, and the data collected by the system probe at different poses can be corrected.

[0102] In one embodiment, as shown in Figure 3 After obtaining the actual pose deviation of the system probe at each pose, the method can further include the following steps:

[0103] S301, moving the target object to a second target position by the translation table.

[0104] In actual application, the target object can be moved to a specific position by the translation table, which can be any position in the scanning area of the SPECT system. For the sake of distinction, the position can be referred to as a second target position. The second target position can be understood as the movement control result of the translation table on the target object, that is, the second target position can be obtained based on the position control information input in the movement control process, and corresponds to the position of the target object in the real world, which can identify the actual position of the target object.

[0105] S302, determining the actual position of the target object in the system coordinate system according to the actual pose difference of the system probe at each pose and the scanning data obtained by the system probe for the target object.

[0106] After the target object is moved to the second target position, the system probe can be used to collect data of the target object at the corresponding pose to obtain scanning data, and then the actual position of the target object in the system coordinate system can be determined according to the actual pose difference of the system probe at each pose and the scanning data.

[0107] S303, obtaining a second expected pose deviation; the second expected pose deviation represents the deviation between the system coordinate system and the translation table coordinate system.

[0108] The system coordinate system is the coordinate system corresponding to the SPECT system, and the translation table coordinate system is the coordinate system corresponding to the translation table. There is a pose deviation between the system coordinate system (X-Y-Z_sys) and the translation table coordinate system (X-Y-Z_pht), for example, Figure 4 A SPECT system and a three-dimensional translation table are shown for the sake of simplicity, Figure 4 which is two-dimensional, but in actual situations, it is three-dimensional.

[0109] In this step, the pose deviation between the system coordinate system and the translation table coordinate system can be predicted, that is, the difference between the system coordinate system and the translation table coordinate system is estimated in advance to determine one or more expected pose deviations. The pose deviation can include the translation deviation between the system coordinate system and the translation table coordinate system, and the rotation angle deviation between the system coordinate system and the translation table coordinate system. For the sake of distinction, the pose deviation can also be referred to as a second expected pose deviation, which can reflect the displacement and / or angular rotation of the system coordinate system relative to the translation table coordinate system.

[0110] S304, determining a predicted position of the target object in the system coordinate system according to the second target position and the second expected pose deviation, and obtaining a second position difference between the expected position and the actual position.

[0111] Specifically, after the target object is moved to the second target position, the second target position can be a position determined with the translational table coordinate system as a reference system, and then the second target position can be coordinate-converted based on the second target position and the second expected pose deviation to calculate a position of the target object in the system coordinate, obtaining the predicted position.

[0112] It can be understood that the actual pose is a position determined according to the scan data collected by the system probe, and the predicted position is a position calculated according to the second target position and the second expected pose deviation. The actual position and the predicted position are two different ways of identifying the same object (i.e., the position of the target object in the system coordinate system). Ideally, the actual position and the predicted position are the same. However, in specific implementations, due to different estimation conditions of the second expected pose deviation, the actual position and the predicted position can be different. By comparing the difference between the actual position and the predicted position, it can be determined whether the second expected pose deviation is accurate.

[0113] Based on this, after the predicted position of the target object is determined, the position difference between the predicted position and the actual position can be determined. For convenience of distinction, the position difference is also referred to as the second position difference.

[0114] S305, determining the actual pose deviation between the system coordinate system and the translational table coordinate according to the second position difference corresponding to each second expected pose deviation.

[0115] Specifically, when the second expected pose deviation is obtained, at least one second expected pose deviation can be obtained. For each second expected pose deviation, the corresponding second position difference under the second expected pose deviation can be obtained based on step S304. It can be understood that the second position difference is related to the second expected pose deviation. The higher the accuracy of the second expected pose deviation, the smaller the second position difference. Based on this, the actual pose deviation between the system coordinate system and the translational table coordinate can be determined according to the second position difference corresponding to each second expected pose deviation.

[0116] In one embodiment, if a plurality of second expected pose deviations Γ2 are obtained in advance, after the second position difference F(Γ2) corresponding to each second expected pose deviation Γ2 is determined, the second position differences F(Γ2) can be compared to determine the second expected pose deviation Γ2 corresponding to the minimum value of F(Γ2), and the second expected pose deviation Γ2 is determined as the actual pose deviation between the system coordinate system and the translational table coordinate.

[0117] In this embodiment, on the one hand, the actual position of the target object in the system coordinate system can be determined based on the actual posture difference of the system probe in each posture, thereby improving the accuracy of the actual position identified by the system; on the other hand, the position of the target object is precisely controlled by the translation stage, so that the second target position accurately corresponds to the actual position of the target object. Therefore, the difference between the predicted position calculated based on the deviation between the second target position and the second expected posture and the actual position can accurately characterize the deviation between the system coordinate system and the translation stage coordinates, thereby improving the accuracy of deviation estimation and correction.

[0118] In one embodiment, step S302, determining the actual position of the target object in the system coordinate system based on the actual position difference of the system probe at each position and the scan data collected by the system probe for the target object, may include the following steps:

[0119] Obtain the scanning data collected by the system probe for the target object; correct the scanning data according to the actual posture difference of the system probe in each posture, and reconstruct the image using the corrected scanning data to obtain a reconstructed image; determine the actual position of the target object in the system coordinate system based on the projection center of the target object on the reconstructed image.

[0120] In a specific implementation, scanning data for a target object can be acquired through a system probe in multiple postures. Since the actual posture of the system probe may differ from the expected posture, after obtaining the scanning data, the scanning data can be corrected according to the actual posture difference of the system probe in each posture to obtain the corrected scanning data. The corrected scanning data can then be used to perform image reconstruction to obtain a reconstructed image corresponding to the target object.

[0121] After acquiring the reconstructed object, the projection center of the target object on the reconstructed image can be determined. In one embodiment, Gaussian fitting can be performed on the projection in three directions perpendicular to each other in the reconstructed image. The three directions perpendicular to each other can be the system coordinate system. Gaussian fitting can be performed on the projection in each direction respectively, and the projection center is determined based on the peak values ​​of the Gaussian fitting in the three directions.

[0122] Then, the actual position of the target object in the system coordinate system can be determined based on the projection center of the target object on the reconstructed image. For example, the projection center position corresponding to the projection center can be obtained, and the projection center position can be determined as the actual position of the target object in the system coordinate system.

[0123] In this embodiment, the reconstructed image of the target object corresponds to the system coordinate system. Based on the projection center of the target object in the reconstructed image, the actual position of the target object in the system coordinate system can be quickly and accurately acquired.

[0124] In one embodiment, the actual detection position and the expected detection position include an actual detection position and an expected detection position respectively acquired when the target object is at a plurality of first target positions, in other words, the target object can be controlled to move to a plurality of different first target positions by the translation stage, and for each first target position, an actual detection position and an expected detection position corresponding to the target object at the first target position are respectively acquired.

[0125] Correspondingly, the step S103 of acquiring the first position difference between the expected detection position and the actual detection position can include the following steps:

[0126] For each first target position, a distance between the corresponding expected detection position and the actual detection position is determined; and the first position difference between the expected detection position and the actual detection position is determined according to the distances of the target object at the first target positions.

[0127] In actual application, after the corresponding expected detection position and the actual detection position of the target object at each first target position are acquired, the distance between the expected detection position and the actual detection position can be determined. Then the distances of the target object at the first target positions can be comprehensively determined to determine the first position difference between the expected detection position and the actual detection position. For example, the first position difference can be determined according to the following formula:

[0128]

[0129] Wherein, when Γ takes the value of Γ1, p i (Γ1) is the expected detection position corresponding to the i-th first target position under the first expected pose deviation Γ1, c i is the actual detection position corresponding to the i-th first target position, f i (Γ1) is the distance between the expected detection position and the actual detection position, and there are m first target positions.

[0130] In this embodiment, the first position difference can be determined in combination with the distances between the expected detection position and the actual detection position of the target object at different first target positions, so as to reduce the deviation in the estimation process and improve the estimation accuracy of the actual pose deviation between the expected pose and the current pose.

[0131] It can be understood that when determining the actual pose deviation between the system coordinate system and the translation stage coordinate, the second position difference can also be determined in the above-mentioned manner, that is, the target object is moved to a plurality of different second target positions, and for each second target position, the distance between the corresponding expected position and the actual position is determined; and the second position difference between the expected position and the actual position is determined according to the distances of the target object at the second target positions. The specific processing can refer to the above-mentioned embodiments, which will not be described here.

[0132] In one embodiment, the target object includes a radioactive source arranged on the mechanical arm of the translation table, as shown in the figure. The radioactive source can be a point source, which can be fixed on the mechanical arm of the translation table. Accordingly, in step S101, moving the target object to the first target position by the translation table control can include the following steps: Figure 4

[0133] sending a radioactive source movement instruction to the translation table, the radioactive source movement instruction being used to instruct the translation table to control the movement of the mechanical arm according to the displacement control information carried by the radioactive source movement instruction, so as to move the radioactive source to the corresponding first target position.

[0134] Specifically, the radioactive source movement instruction can be sent to the translation table to trigger the movement of the radioactive source. After receiving the radioactive source movement instruction, the translation table can obtain the displacement control information carried by the radioactive source movement instruction, and the displacement control information can indicate the movement direction and movement amplitude of the mechanical arm of the translation table. Then, the translation table can control the movement of the mechanical arm according to the displacement control information, so that the radioactive source can move to the corresponding first target position.

[0135] In this embodiment, by arranging the radioactive source on the mechanical arm, the precise control of the position of the radioactive source can be realized by controlling the displacement of the mechanical arm.

[0136] In order for those skilled in the art to better understand the above steps, the embodiments of the present application are exemplarily described by an example below, but it should be understood that the embodiments of the present application are not limited thereto.

[0137] In a specific implementation, the SPECT system and the translation table have corresponding coordinate systems, respectively represented as X-Y-Z_sys and X-Y-Z_pht; the coordinate systems of the system probe in the expected pose and the current pose also have differences, respectively represented as X-Y-Z_det_ide and X-Y-Z_det_rea.

[0138] Wherein, X-Y-Z_sys and X-Y-Z_pht have the following transformation relationship:

[0139] {Xpht} = {RRsys, pht} {Xsys} + {Tsys, pht}

[0140] {Rsys, pht, Tsys, pht}

[0141] ​Where {Xsys} and {Xpht} are three-row, one-column vectors representing the coordinates of any point in the system coordinate system XY-Z_sys and the translation stage coordinate system XY-Z_pht, respectively. {Tsys,pht} is a three-row, one-column vector representing the translation of the origin between the two coordinate systems. {Rsys,pht} is a three-row, three-column matrix representing the rotation between the two coordinate systems. Γsys,pht are the parameters to be estimated.

[0142] Under a certain posture (such as a certain rotation angle θ), XY-Z_det_ide and XY-Z_det_rea have the following transformation relationship:

[0143] {X det_ide}={R ide，rea}{X det_rea}+{T ide，rea}

[0144] Γ ide，rea ={R ide，rea , T ide，rea}

[0145] Among them, {X det_rea} and {X det_rea} is a vector with three rows and one column, which represents the coordinates of any point in the coordinate system XY-Z_det_rea and the coordinates of any point in the coordinate system XY-Z_det_ide, {T ide，rea} is a vector with three rows and one column, which represents the translation of the origin of the two coordinate systems mentioned above, {R ide，rea} is a three-row and three-column matrix that represents the rotation between the two coordinate systems mentioned above. ide，rea is the parameter to be estimated.

[0146] To facilitate the distinction in the following text, Γ ide，rea is called geometric parameter 1, and Γ sys，pht It is called geometric parameter 2.

[0147] like Figure 5 As shown, the geometric parameters 1 and 2 can be initialized to 0 first, and then the system probe can be rotated to a certain angle, and the translation stage can be triggered to control the radioactive point source to move to m positions and perform data acquisition to determine the corresponding expected detection position and actual detection position. When the geometric parameter 2 is fixed, the expected detection position and actual detection position are determined according to the point source at different positions, and the geometric parameter 1 at the current angle is obtained.

[0148] After obtaining the geometric parameter 1 at the current angle, it can be determined whether all angles have been traversed. If not, the process can return to the step of rotating the system probe to the next angle until the geometric parameter 1 at each angle is obtained.

[0149] Then, the translation table control can be continued to trigger the radioactive point source to move to n positions, data acquisition is performed at multiple angles by the system probe, scan data is obtained, and then the point source image is reconstructed according to the geometric parameter 1 and the scan data, the actual position of the point source in the system coordinate system is determined, and the geometric parameter 2 is updated according to the corresponding predicted position. If the current satisfies the stopping condition, the process can be ended, otherwise, the step of rotating the system probe to the next angle is returned to execute, the geometric parameter 2 is fixed, and the geometric parameter 1 is updated again.

[0150] It should be understood that, although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, there is no strict order limitation for the execution of these steps, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be alternately executed with at least part of other steps or steps or stages in other steps.

[0151] Based on the same inventive concept, the embodiments of the present application also provide a single photon emission computed tomography system deviation acquisition device for implementing the single photon emission computed tomography system deviation acquisition method described above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more single photon emission computed tomography system deviation acquisition device embodiments provided below can refer to the limitations of the single photon emission computed tomography system deviation acquisition method in the above text, and will not be repeated here.

[0152] In one exemplary embodiment, as shown in FIG. 6, a single photon emission computed tomography system deviation acquisition device is provided, comprising: Figure 6

[0153] The actual detection position determination module 601 is configured to determine the actual detection position of the target object recognized by the system probe at the current pose by controlling the target object to move to the first target position by the translation table.

[0154] The first deviation prediction module 602 is configured to acquire a first expected pose deviation; the first expected pose deviation represents the deviation between the expected pose and the current pose of the system probe.

[0155] ​The expected detection position determination module 603 is configured to determine an expected detection position of the target object according to the first target position and the first expected pose deviation, and obtain a first position difference between the expected detection position and the actual detection position.

[0156] The probe pose deviation determination module 604 is configured to determine an actual pose deviation between the expected pose and the current pose of the system probe according to the first position difference corresponding to each of the first expected pose deviations.

[0157] In an embodiment, the actual detection position determination module 601 is configured to:

[0158] determine a projection of the target object on a detection surface of the system probe when the target object is at the first target position; the probe plane is the detection surface corresponding to the system probe in the current pose;

[0159] determine the actual detection position of the target object recognized by the system probe according to a projection center of the projection on the detection surface.

[0160] In an embodiment, the apparatus is further configured to:

[0161] adjust the current pose of the system probe, and redetermine an actual pose difference between the expected pose and the current pose of the system probe after the pose adjustment to obtain the actual pose difference of the system probe in each pose.

[0162] In an embodiment, the apparatus further comprises:

[0163] The second target position moving module is configured to control the target object to move to a second target position through the translation table;

[0164] The actual position determination module is configured to determine an actual position of the target object in the system coordinate system according to the actual pose difference of the system probe in each pose and scanning data collected by the system probe for the target object;

[0165] The second deviation prediction module is configured to obtain a second expected pose deviation; the second expected pose deviation represents a deviation between the system coordinate system and the translation table coordinate system;

[0166] The predicted position determination module is configured to determine a predicted position of the target object in the system coordinate system according to the second target position and the second expected pose deviation, and obtain a second position difference between the predicted position and the actual position.

[0167] The coordinate system pose deviation determination module is configured to determine an actual pose deviation between the system coordinate system and the translation table coordinate according to the second position difference corresponding to each of the second expected pose deviations.

[0168] In one embodiment, the actual position determination module is configured to:

[0169] acquire scan data collected by the system probe for the target object;

[0170] correct the scan data according to the actual pose difference of the system probe at each pose, perform image reconstruction using the corrected scan data, and obtain a reconstructed image;

[0171] determine an actual position of the target object in the system coordinate system according to the projection center of the target object on the reconstructed image.

[0172] In one embodiment, the actual detection position and the expected detection position include actual detection positions and expected detection positions respectively acquired when the target object is at a plurality of first target positions;

[0173] The expected detection position determination module 603 is configured to:

[0174] determine a distance between the corresponding expected detection position and the actual detection position for each first target position;

[0175] determine a first position difference between the expected detection position and the actual detection position according to the distance of the target object at each first target position.

[0176] In one embodiment, the target object includes a radioactive source arranged on a mechanical arm of a translation table;

[0177] The actual detection position determination module 601 is configured to:

[0178] send a radioactive source movement instruction to the translation table, the radioactive source movement instruction being used to instruct the translation table to control movement of the mechanical arm according to displacement control information carried by the radioactive source movement instruction, so as to move the radioactive source to the corresponding first target position.

[0179] Each module in the deviation acquisition device of the single-photon emission computed tomography system described above can be realized by software, hardware, and a combination thereof, in whole or in part. Each module described above can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in a computer device in software form, so as to be called and executed by a processor to perform operations corresponding to each module.

[0180] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store posture data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a deviation acquisition method for a single-photon emission computed tomography imaging system is implemented.

[0181] In an exemplary embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as shown in FIG. Figure 8 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a deviation acquisition method for a single photon emission computed tomography imaging system is implemented. The display unit of the computer device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0182] Those skilled in the art will understand that Figure 7and Figure 8 The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0183] In an embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program, and the processor implementing the steps in the above method embodiments when executing the computer program.

[0184] In an embodiment, a computer readable storage medium is provided, storing a computer program, and the computer program implementing the steps in the above method embodiments when executed by a processor.

[0185] In an embodiment, a computer program product is provided, including a computer program, and the computer program implementing the steps in the above method embodiments when executed by a processor.

[0186] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of related data need to comply with relevant regulations.

[0187] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (Read-Only Memory, ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (Magnetoresistive Random Access Memory, MRAM), ferroelectric memory (Ferroelectric Random Access Memory, FRAM), phase change memory (Phase Change Memory, PCM), graphene memory, etc. Volatile memory can include random access memory (Random Access Memory, RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (Static Random Access Memory, SRAM) or dynamic random access memory (Dynamic Random Access Memory, DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0188] Any combination of the technical features of the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0189] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for obtaining a deviation of a single photon emission computed tomography system, characterized in that: The method comprises: Controlling the target object to move to a first target position by a translation stage, and determining an actual detection position of the target object identified by the system probe in the current posture; Obtaining a first expected posture deviation; the first expected posture deviation represents a deviation between an expected posture and a current posture of the system probe; Determining an expected detection position of the target object according to the first target position and the first expected posture deviation, and obtaining a first position difference between the expected detection position and the actual detection position; An actual posture deviation between the expected posture of the system probe and the current posture is determined according to the first position difference corresponding to each of the first expected posture deviations.

2. The method according to claim 1, characterized in that The determining of the actual detection position of the target object identified by the system probe in the current posture includes: Determine a projection of the target object on a detection surface corresponding to the system probe when the target object is at the first target position; the probe plane is the detection surface corresponding to the system probe in the current posture; An actual detection position of the target object identified by the system probe is determined according to a projection center of the projection on the detection surface.

3. The method according to claim 1, characterized in that After determining the actual posture deviation between the expected posture and the current posture of the system probe according to the first position difference corresponding to each of the first expected posture deviations, the method further includes: The current posture of the system probe is adjusted, and the actual posture difference between the expected posture of the system probe after the posture adjustment and the current posture is re-determined to obtain the actual posture difference of the system probe in each posture.

4. The method according to claim 3, characterized in that After obtaining the actual posture difference of the system probe in each posture, the method further includes: Controlling the target object to move to a second target position by the translation stage; Determining the actual position of the target object in the system coordinate system according to the actual posture difference of the system probe at each posture and the scanning data collected by the system probe for the target object; Obtaining a second expected posture deviation; the second expected posture deviation represents a deviation between the system coordinate system and the translation stage coordinate system; Determining a predicted position of the target object in the system coordinate system according to the second target position and the second expected posture deviation, and obtaining a second position difference between the predicted position and the actual position; The actual posture deviation between the system coordinate system and the translation stage coordinates is determined according to the second position difference corresponding to each of the second expected posture deviations.

5. The method according to claim 4, characterized in that Determining the actual position of the target object in the system coordinate system according to the actual posture difference of the system probe in each posture and the scanning data collected by the system probe for the target object includes: Acquiring scanning data collected by the system probe on the target object; Correcting the scan data according to actual posture differences of the system probe at various postures, and reconstructing an image using the corrected scan data to obtain a reconstructed image; The actual position of the target object in the system coordinate system is determined according to the projection center of the target object on the reconstructed image.

6. The method according to any one of claims 1 to 5, characterized in that The actual detection position and the expected detection position include actual detection positions and expected detection positions respectively obtained when the target object is at a plurality of first target positions; The obtaining of a first position difference between the expected detection position and the actual detection position includes: For each first target position, determining a distance between the corresponding expected detection position and the actual detection position; A first position difference between the expected detection position and the actual detection position is determined according to the distance of the target object at each first target position.

7. The method according to any one of claims 1 to 5, characterized in that The target object includes a radiation source disposed on a mechanical arm of a translation stage; The step of controlling the target object to move to the first target position by using the translation stage includes: A radiation source movement instruction is sent to the translation stage, where the radiation source movement instruction is used to instruct the translation stage to control the movement of the robotic arm according to displacement control information carried by the radiation source movement instruction, so that the radiation source moves to the corresponding first target position.

8. A deviation acquisition device for a single photon emission computed tomography system, characterized in that: The device comprises: An actual detection position determination module is used to control the target object to move to a first target position through a translation stage, and determine the actual detection position of the target object identified by the system probe in the current posture; A first deviation prediction module is configured to obtain a first expected posture deviation; the first expected posture deviation represents a deviation between an expected posture and a current posture of the system probe; an expected detection position determining module, configured to determine an expected detection position of the target object based on the first target position and the first expected posture deviation, and obtain a first position difference between the expected detection position and the actual detection position; The probe posture deviation determination module is used to determine the actual posture deviation between the expected posture and the current posture of the system probe according to the first position difference corresponding to each of the first expected posture deviations.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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