Methods, apparatus, and collimator assemblies to determine target positions of single-slit collimating plates

Abstract

A method (100), device (800) and collimator assembly (20, 30) for determining a target position of a single-slit collimator plate (23). The method (100) comprises: acquiring a first measurement signal (101) based on a first air scan when the single-slit collimator plate (23) is moved a predetermined distance in a first direction along a Z-axis from a starting position to a first position; acquiring a second measurement signal (102) based on a second air scan when the single-slit collimator plate (23) is moved a predetermined distance in a reverse direction of the first direction from the starting position to a second position; determining a combined measurement signal and a combined air calibration signal (103) based on the first measurement signal and the second measurement signal; calibrating the combined measurement signal with the combined air calibration signal (104); and determining the target position of the single-slit collimator plate (23) based on the calibrated combined measurement signal (105). The target position of the single-slit collimator plate (23) is determined by two air scans, which is simple and convenient.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a method, apparatus and collimator assembly for determining the target position of a single-slot collimator, as well as a control host and computer-readable storage medium for a CT system. Background Technology

[0002] In computed tomography (CT), precisely collimated X-rays, along with highly sensitive detectors, scan a specific part of the body section by section. A collimator is a device that limits the orientation of X-ray exposure and determines the size of the radiation field, significantly reducing interference from scattered radiation and confining X-rays to the desired area. Therefore, collimators improve image quality and reduce the radiation dose received by the patient. Collimators in a CT scanner typically include an X-ray source-side collimator and a detector-side collimator. The placement of the X-ray source-side collimator has a significant impact on image quality.

[0003] Currently, X-ray source-side collimators generally adopt a multi-slot structure. During the factory tuning phase, multiple air scans are required to determine the arrangement of the multi-slots, and the tuning method is both time-consuming and complex.

[0004] The industry has been committed to developing simple and convenient collimators and adjustment schemes. For example, Chinese invention patent application No. 201110081593.5 discloses a Z collimator, which includes two rotatable collimating plates in the Z direction. Each collimating plate includes a plurality of collimating feet of different lengths. By rotating, the collimating feet of the same length in the two collimating plates are made to form a collimating foot pair for collimation. Summary of the Invention

[0005] The main objective of this invention is to provide a method, apparatus, and collimator assembly for determining the target position of a single-slot collimator. This invention also aims to provide a control host for a CT system and a computer-readable storage medium.

[0006] The technical solution of the embodiments of the present invention is implemented as follows:

[0007] A method for determining the target position of a single-slot collimator includes:

[0008] Acquire the first measurement signal based on the first air scan when the single-slot collimator moves a predetermined distance from the starting position along the first direction of the Z-axis to the first position;

[0009] Acquire a second measurement signal based on a second air scan when the single-slot collimator moves a predetermined distance from the starting position in the opposite direction of the first direction to the second position;

[0010] Based on the first and second measurement signals, the synthesized measurement signal and the synthesized air calibration signal are determined;

[0011] The synthetic measurement signal is calibrated using the synthetic air calibration signal;

[0012] The target position of the single-slot collimator is determined based on the calibrated synthetic measurement signal.

[0013] As can be seen, the embodiment of the present invention uses a single-slot collimator, which only requires air scanning at two slot positions to obtain the calibrated synthetic measurement signal, and the target position of the single-slot collimator can be quickly calculated based on the calibrated synthetic measurement signal. Compared with the shortcomings of existing collimators with multi-slot structures that require multiple air scans, the embodiment of the present invention reduces the number of air scans and has the advantages of being more efficient, simple, and convenient.

[0014] In one embodiment, determining the synthetic measurement signal and the synthetic air calibration signal based on the first measurement signal and the second measurement signal includes:

[0015] Determine the boundary point between the first measurement signal and the second measurement signal;

[0016] The first signal segment of the second measurement signal, which extends from the dividing point along the first direction of the Z-axis, is combined with the second signal segment of the first measurement signal, which extends from the dividing point along the opposite direction, to form the composite measurement signal.

[0017] The third signal region in the first measurement signal, which extends from the dividing point along the first direction of the Z-axis, is combined with the fourth signal segment in the second measurement signal, which extends from the dividing point along the opposite direction, to form the synthetic air calibration signal.

[0018] Therefore, the embodiments of the present invention can conveniently combine the first measurement signal and the second measurement signal to generate a synthetic measurement signal and a synthetic air calibration signal.

[0019] In one embodiment, determining the target position of the single-slot collimator based on the calibrated synthetic measurement signal includes:

[0020] Determine the centroid of the calibrated synthetic measurement signal;

[0021] The target position of the single-slot collimator is determined based on the center of gravity.

[0022] As can be seen, by determining the centroid of the calibrated synthetic measurement signal, the target position of the single-slot collimator can be quickly determined in the embodiments of the present invention.

[0023] In one implementation, determining the centroid of the calibrated synthetic measurement signal includes:

[0024] The left channel group, the right channel group, and the middle channel group located between the left channel group and the right channel group are determined based on the channel numbering order.

[0025] Determine the first average signal of the calibrated synthetic measurement signal for each channel in the intermediate channel group;

[0026] Determine the centroid of the first average signal;

[0027] The determination of the target position of the single-slot collimator based on the center of gravity includes: determining the Z position offset of the single-slot collimator based on the center of gravity of the first average signal.

[0028] Therefore, the embodiments of the present invention can calculate the precise optimal Z position offset based on the centroid of the first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group, which facilitates the subsequent precise adjustment of the Z position of the single-slot collimator.

[0029] In one embodiment, determining the centroid of the calibrated synthetic measurement signal further includes:

[0030] Determine the second average signal of the calibrated synthetic measurement signal for each channel in the left channel group;

[0031] Determine the centroid of the second average signal;

[0032] Determine the third average signal of the calibrated composite measurement signal for each channel in the right channel group;

[0033] Determine the centroid of the third average signal;

[0034] The method of determining the target position of the single-slot collimator based on the center of gravity further includes: determining the parallelism of the single-slot collimator based on the center of gravity of the second average signal and the center of gravity of the third average signal.

[0035] Therefore, the embodiments of the present invention can calculate the precise optimal parallelism based on the centroids of the second and third average signals, facilitating subsequent precise adjustment of the parallelism of the single-slot collimator. In one embodiment, the method further includes:

[0036] The curvature of the single-slot collimator is determined based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal.

[0037] When the curvature exceeds a predetermined curvature threshold, an alarm message is issued prompting the replacement of the single-slot collimator.

[0038] Therefore, the embodiments of the present invention can calculate the curvature of the single-slot collimator based on the centroid of the second average signal and the centroid of the third average signal, and issue an alarm message to remind the user to replace the single-slot collimator when the calculated curvature exceeds the standard.

[0039] An apparatus for determining the target position of a single-slot collimator, comprising:

[0040] The first acquisition module is used to acquire the first measurement signal based on the first air scan when the single slot collimator moves a predetermined distance from the starting position along the first direction of the Z-axis to the first position.

[0041] The second acquisition module is used to acquire a second measurement signal based on the second air scan when the single-slot collimator moves a predetermined distance from the starting position in the opposite direction of the first direction to the second position.

[0042] The first determining module is used to determine the synthesized measurement signal and the synthesized air calibration signal based on the first measurement signal and the second measurement signal;

[0043] A calibration module is used to calibrate the synthetic measurement signal using the synthetic air calibration signal;

[0044] The second determining module is used to determine the target position of the single-slot collimator based on the calibrated synthetic measurement signal.

[0045] As can be seen, the embodiment of the present invention uses a single-slot collimator, which only requires air scanning at two slot positions to obtain the calibrated synthetic measurement signal, and the target position of the single-slot collimator can be quickly calculated based on the calibrated synthetic measurement signal. Compared with the shortcomings of existing collimators with multi-slot structures that require multiple air scans, the embodiment of the present invention reduces the number of air scans and has the advantages of being more efficient, simple, and convenient.

[0046] In one embodiment, a first determining module is configured to determine the boundary point between a first measurement signal and a second measurement signal; combine a first signal segment of the second measurement signal extending from the boundary point along a first direction of the Z-axis with a second signal segment of the first measurement signal extending from the boundary point along the opposite direction to form the composite measurement signal; and combine a third signal region of the first measurement signal extending from the boundary point along the first direction of the Z-axis with a fourth signal segment of the second measurement signal extending from the boundary point along the opposite direction to form the composite air calibration signal.

[0047] Therefore, the embodiments of the present invention can conveniently combine the first measurement signal and the second measurement signal to generate a synthetic measurement signal and a synthetic air calibration signal.

[0048] In one embodiment, the second determining module is used to determine the centroid of the calibrated synthetic measurement signal and determine the target position of the single-slot collimator based on the centroid.

[0049] As can be seen, by determining the centroid of the calibrated synthetic measurement signal, the target position of the single-slot collimator can be quickly determined in the embodiments of the present invention.

[0050] In one embodiment, the second determining module is configured to determine a left channel group, a right channel group, and an intermediate channel group located between the left and right channel groups based on the channel numbering order; determine a first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group; determine the centroid of the first average signal; and determine the Z position offset of the single-slot collimator based on the centroid of the first average signal.

[0051] Therefore, the embodiments of the present invention can calculate the precise optimal Z position offset based on the centroid of the first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group, which facilitates the subsequent precise adjustment of the Z position of the single-slot collimator.

[0052] In one embodiment, the second determining module is further configured to determine a second average signal of the calibrated synthetic measurement signal of each channel in the left channel group; determine the centroid of the second average signal; determine a third average signal of the calibrated synthetic measurement signal of each channel in the right channel group; determine the centroid of the third average signal; and determine the parallelism of the single-slot collimator based on the centroids of the second and third average signals.

[0053] Therefore, the embodiments of the present invention can calculate the precise optimal parallelism based on the centroid of the second average signal and the centroid of the third average signal, which facilitates the subsequent precise adjustment of the parallelism of the single-slot collimator.

[0054] In one embodiment, the second determining module is further configured to determine the curvature of the single-slot collimator based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal; the device further includes:

[0055] An alarm module is used to issue an alarm message prompting the replacement of the single-slot collimator when the curvature exceeds a predetermined curvature threshold.

[0056] Therefore, the embodiments of the present invention can calculate the curvature of the single-slot collimator based on the centroid of the second average signal and the centroid of the third average signal, and issue an alarm message to remind the user to replace the single-slot collimator when the calculated curvature exceeds the standard.

[0057] A collimator assembly, comprising:

[0058] The frame is adapted to be placed on a rotating carrier;

[0059] A single-slot collimator is arranged in the frame;

[0060] The pivot point is fixed at the first end of the frame.

[0061] A spring is arranged between the opposite end of the first end of the frame and the rotating carrier;

[0062] The single-slot collimator includes a groove, and the frame has rotational freedom about the pivot point;

[0063] The single-groove aligning plate is adapted to be moved to a target position during the rotation of the frame about the pivot point or during the filling of a shim in the groove, wherein the target position is determined as described in any of the preceding methods.

[0064] As can be seen, the embodiments of the present invention also propose a collimator assembly whose position can be easily adjusted. By rotating the frame about the pivot point, the parallelism of the single-slot collimator plate can be easily adjusted; by filling the groove with a shim, the Z position of the single-slot collimator plate can be easily adjusted.

[0065] A collimator assembly, comprising:

[0066] A frame adapted to be arranged on a rotating carrier, wherein a first groove and a second groove are arranged parallel to each other along the Z-axis.

[0067] A single-slot collimator is arranged in the frame;

[0068] A first spring, the first end of which is fixed to the frame, and the second end of which is in contact with the side wall of the single-slot collimator;

[0069] The second spring has its first end fixed to the frame and its second end in contact with the side wall.

[0070] The first end of the single-slot collimator has a degree of freedom of movement along the first slot, and the opposite end of the first end of the single-slot collimator has a degree of freedom of movement along the second slot; the single-slot collimator is adapted to be adjusted to a target position based on a combination of movement of the first end of the single-slot collimator along the first slot and movement of the opposite end of the first end of the single-slot collimator along the second slot, movement of the first end of the single-slot collimator along the first slot, or movement of the opposite end of the first end of the single-slot collimator along the second slot; wherein the target position is determined by the method described in any of the preceding claims.

[0071] As can be seen, the embodiments of the present invention also provide a collimator assembly with convenient position adjustment. The target position of the single-slot collimator can be conveniently adjusted by moving the first end of the single-slot collimator individually, moving the second end of the single-slot collimator individually, or moving the first and second ends of the single-slot collimator in combination.

[0072] A control host for a CT system includes: a memory; a processor; wherein the memory stores an application program executable by the processor, for causing the processor to perform the method described in any of the preceding methods.

[0073] Therefore, this invention also proposes a control host that can quickly determine the target position of a single-slot collimator.

[0074] A computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the method as described in any of the preceding claims.

[0075] Therefore, embodiments of the present invention also propose a computer-readable storage medium that can quickly determine the target position of a single-slot collimator. Attached Figure Description

[0076] Figure 1 A flowchart illustrating a method for determining the target position of a single-slot collimator according to an embodiment of the present invention.

[0077] Figure 2 This is a schematic cross-sectional view of an air scan of a CT scanner along the Z-axis direction according to an embodiment of the present invention.

[0078] Figure 3 This is a schematic diagram illustrating the combination of signals to obtain a synthetic measurement signal according to an embodiment of the present invention.

[0079] Figure 4 This is a schematic diagram illustrating the synthesis of an air calibration signal according to an embodiment of the present invention.

[0080] Figure 5 This is a schematic diagram of the synthesized measurement signal after calibration according to an embodiment of the present invention.

[0081] Figure 6 This is a first schematic diagram illustrating the adjustment of the target position of the single-slot collimator plate in the collimator assembly according to an embodiment of the present invention.

[0082] Figure 7 This is a first schematic diagram illustrating the adjustment of the target position of the single-slot collimator plate in the collimator assembly according to an embodiment of the present invention.

[0083] Figure 8 A structural diagram of an apparatus for determining the target position of a single-slot collimator according to an embodiment of the present invention.

[0084] Figure 9 This is a structural diagram of the control host of a CT system according to an embodiment of the present invention.

[0085] The accompanying figure is labeled as follows:

[0086] Reference signs Meaning 100 Method for determining target position of single-slot collimator plate 101～105 Steps 10 Slot plate located at initial - shift position in Z-axis direction 11 Slot plate located at initial + shift position in Z-axis direction 12～15 X-ray 16 Second signal segment 17 First signal segment

[0087] 18 Fourth signal segment 19 Third signal segment 40 Focus 50 Detector array 70 First signal 80 Second signal 90 Calibrated combined measurement signal 20 Collimator assembly 21 Frame 22 Rotating carrier 23 Single-slot collimator plate 24 Rotational pivot point 25 Spring 26 Groove 27 Handle 28 Positioning pin 29 Fixing bolt 40 Screw micrometer 30 Collimator assembly 31 Frame 33 First slot 34 Second slot 35 First spring 36 Second spring 37 Single-slot collimator plate 41 First screw micrometer 42 Second screw micrometer 800 Device for determining target position of single-slot collimator plate 801 First acquisition module 802 Second acquisition module 803 First determination module 804 Calibration module 805 Second determination module 806 Alarm module

[0088] 900 Control host of CT system 901 Memory 902 Processor Detailed Implementation

[0089] To make the technical solutions and advantages of the present invention clearer, the present invention 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 merely illustrative of the present invention and are not intended to limit the scope of protection of the present invention.

[0090] For the sake of brevity and intuitiveness, the following description uses several representative embodiments to illustrate the solution of the present invention. Numerous details in the embodiments are only used to aid in understanding the solution of the present invention. However, it is obvious that the technical solution of the present invention can be implemented without being limited to these details. To avoid unnecessarily obscuring the solution of the present invention, some embodiments are not described in detail, but only a framework is given. In the following text, "comprising" means "including but not limited to," and "according to..." means "at least according to..., but not limited to only according to...". Due to Chinese language habits, unless the quantity of a component is specifically indicated below, it means that the component can be one or more, or can be understood as at least one.

[0091] The applicant found that in the prior art, X-ray source-side collimators typically employ a multi-slot structure, thus requiring multiple (e.g., at least seven) air scans during the factory adjustment phase to determine the slot placement, making the adjustment process time-consuming and complex. Furthermore, the prior art requires additional mechanical motors or control components to assist in slot adjustment, further increasing complexity and leading to cost issues.

[0092] Considering the adjustment complexity of multi-slot structures, this embodiment of the invention replaces the multi-slot collimator with a single-slot collimator containing a single-slot collimator plate, thereby reducing the complexity of the adjustment process. Furthermore, this embodiment of the invention determines the target position based on signal centroid calculation, ensuring adjustment accuracy. Additionally, this embodiment of the invention can save costs associated with mechanical motors or control components.

[0093] Figure 1 This is a flowchart illustrating a method for determining the target position of a single-slot collimator according to an embodiment of the present invention. A single-slot collimator, including the single-slot collimator, is arranged on the X-ray source side.Figure 1 The method shown is preferably executed by the control host of the CT system.

[0094] like Figure 1 As shown, the method includes:

[0095] Step 101: Obtain the first measurement signal based on the first air scan when the single-slot collimator moves a predetermined distance along the first direction of the Z-axis from the starting position to the first position.

[0096] Here, the Z-axis represents the row (ROW) arrangement direction of the detector array.

[0097] When the single-slot collimator moves a predetermined distance along the first direction of the Z-axis from its starting position to a first position, the CT system performs the first air scan. The detector array of the CT system detects the measurement signal of the first air scan (referred to as the first measurement signal). The first measurement signal is determined by the X-ray intensities detected by each row on the Z-axis during the first air scan. For example, the first measurement signal can be described using the X-ray intensity or the logarithm of the X-ray intensity. Furthermore, the detector array transmits the first measurement signal to the control host via a transmission link such as a cable.

[0098] Step 102: Obtain the second measurement signal based on the second air scan when the single-slot collimator moves the predetermined distance from the starting position in the opposite direction of the first direction to the second position.

[0099] Here, the single-slot collimator is returned from the first position to the starting position. Furthermore, when the single-slot collimator moves a predetermined distance from the starting position in the opposite direction of the first direction of the Z-axis to the second position, the CT system performs a second air scan. The detector array detects the measurement signal of the second air scan (referred to as the second measurement signal). The second measurement signal is determined by the X-ray intensities detected in each row of X-rays along the Z-axis during the second air scan. For example, the second measurement signal can be described using the X-ray intensity, or using the logarithm of the X-ray intensity. Moreover, the detector array transmits this second measurement signal to the control host via a transmission link such as a cable.

[0100] Figure 2 This is a schematic cross-sectional view of an air scan of a CT scanner along the Z-axis direction according to an embodiment of the present invention.

[0101] The single-slot collimator starts from the initial position and moves along... Figure 2 The Z-axis is reversed (i.e.) Figure 2(In the opposite direction of the arrow marked Z), the system moves a predetermined distance (shift) to the current position (initial-shift). Then, the CT system performs the first air scan. Specifically, the X-rays emitted from the focal spot 40 are confined by the single-slot collimator 10 at the moved current position (initial-shift), forming a transmission range defined by X-rays 12 and 13. When the detector array 50 has a sufficient number of rows in the Z-axis direction, the detector array 50 can detect the measurement signal identified by the complete solid line curve 70. However, since the detector array 50 typically has only a limited number of rows, it may not actually be able to completely detect the solid line curve 70. For example, as... Figure 2 As shown, the detector array 50, comprising the first row R1, the second row R2, ... the nth row Rn, detects the measurement signal, identified by the solid curve BE, within this transmission range. Point B is the intersection of the line connecting the end of the first row R1 in the reverse Z-axis direction with the focal point 40 and the solid curve 70; point E is the intersection of X-ray 13 and the detector array 50. It is evident that the solid curve BE is a portion of the solid curve 70. The solid curve BE represents the measurement signal (first measurement signal) detected by the detector array 50 for the first air scan, determined by the intensity of the X-rays detected by each row in the Z-axis direction during the first air scan.

[0102] Then, the single-slot collimator returns from its current position (initial-shift) to its initial position (initial), and from the initial position (initial), it moves along... Figure 2 The positive Z-axis shown (i.e. Figure 2 (In the direction of the arrow marked Z), move the same predetermined distance (shift) to the current position (initial+shift). Then, the CT system performs a second air scan. Specifically, the X-rays emitted from focal spot 40 are confined by the single-slot collimator 11 at the moved current position (initial+shift), forming a transmission range defined by X-rays 14 and 15. When detector array 50 has a sufficient number of rows, it can detect the measurement signal identified by the complete dashed curve 80. However, since detector array 50 typically has only a limited number of rows, it may not actually be able to completely detect the dashed curve 80. For example, as... Figure 2As shown, the detector array 50, comprising the first row R1, the second row R2... the nth row Rn, detects the measurement signal, marked by the dashed curve DC, within this transmission range. Point C is the intersection of the line connecting the end of the nth row Rn in the positive Z-axis direction with the focal point 40 and the dashed curve 80; point D is the intersection of X-ray 14 and the detector array 50. It is evident that the dashed curve DC is a portion of the dashed curve 80. The dashed curve DC represents the measurement signal (second measurement signal) detected by the detector array 50 for the second air scan, determined by the intensity of the X-rays detected by each row in the Z-axis direction during the second air scan.

[0103] Step 103: Based on the first measurement signal and the second measurement signal, determine the synthesized measurement signal and the synthesized air calibration signal.

[0104] Here, the control host determines the synthetic measurement signal and the synthetic air calibration signal based on the first measurement signal and the second measurement signal.

[0105] In one embodiment, step 103, determining the synthesized measurement signal and the synthesized air calibration signal based on the first and second measurement signals, includes: determining the boundary point between the first and second measurement signals; combining a first signal segment in the second measurement signal extending from the boundary point along a first direction of the Z-axis with a second signal segment in the first measurement signal extending from the boundary point in the opposite direction to form a synthesized measurement signal; and combining a third signal region in the first measurement signal extending from the boundary point along the first direction of the Z-axis with a fourth signal segment in the second measurement signal extending from the boundary point in the opposite direction to form a synthesized air calibration signal. The boundary point can be the intersection of the first and second measurement signals, or a point surrounding the intersection of the first and second measurement signals.

[0106] Accept Figure 2 For example, point A is the intersection of the first measurement signal and the second measurement signal. Point A is taken as the boundary point between the first measurement signal and the second measurement signal.

[0107] The solid line AE contained within the solid curve BE is the second signal segment 17, and the dashed line DA contained within the dashed curve DC is the first signal segment 16. Combining the first signal segment 16 and the second signal segment 17 yields the synthesized measurement signal.

[0108] Figure 3 This is a schematic diagram illustrating the combination of signals to obtain a synthetic measurement signal according to an embodiment of the present invention. Figure 3 In the figure, the curve formed by the combination of the first signal segment 16 and the second signal segment 17 through point A is the composite measurement signal.

[0109] The solid line BA contained within the solid curve BE is the third signal segment 19, and the dashed line AC contained within the dashed curve DC is the fourth signal segment 18. Combining the third signal segment 19 and the fourth signal segment 18 yields the synthesized air calibration signal.

[0110] Figure 4 This is a schematic diagram illustrating the synthesis of an air calibration signal according to an embodiment of the present invention. Figure 4 In the middle, the third signal segment 19 and the fourth signal segment 18 are combined through point A to form a whole curve, which is the synthetic air calibration signal.

[0111] Step 104: Calibrate the synthetic measurement signal using the synthetic air calibration signal.

[0112] Here, the control host uses the synthetic measurement signal to calibrate the synthetic air calibration signal, thus obtaining the calibrated synthetic measurement signal.

[0113] Specifically, when both the first and second measurement signals are described by the logarithm of the X-ray intensities detected in their respective air scans (i.e., the X-ray intensities detected in their respective air scans for both the first and second measurement signals are logarithmically calculated), a calibrated synthetic air calibration signal can be obtained by subtracting the synthetic air calibration signal from the synthetic measurement signal. Alternatively, when both the first and second measurement signals are described by the X-ray intensities detected in their respective air scans (i.e., the X-ray intensities detected in their respective air scans for both the first and second measurement signals are not logarithmically calculated), a calibrated synthetic air calibration signal can be obtained by dividing the synthetic measurement signal by the synthetic air calibration signal.

[0114] Figure 5 This is a schematic diagram of the synthesized measurement signal after calibration according to an embodiment of the present invention. Figure 5 In the center, the calibrated synthetic measurement signal 90 is displayed in a coordinate system with the row number as the horizontal axis and the signal strength as the vertical axis.

[0115] Step 105: Determine the target position of the single-slot collimator based on the calibrated synthetic measurement signal.

[0116] Here, the control host can first determine the centroid of the calibrated synthetic measurement signal, and then determine the target position of the single-slot collimator based on the centroid. The specific method by which the control host determines the centroid of the calibrated synthetic measurement signal can refer to various centroid (Center of Gravity, COG) algorithms, and this embodiment of the invention is not limited in this regard.

[0117] Each detector in a detector array has multiple channels in the channel direction, where the channel direction refers to the arrangement of the channels in the detector array. Detector arrays are typically curved, therefore the channel direction is usually curved. For example, ... Figure 2 As shown in the lower right corner, in the three-dimensional rectangular coordinate system (XYZ), the Z-axis direction is the arrangement direction of the rows in the detector array, the channel direction Φ is located in the XY plane perpendicular to the Z-axis, and the channel direction Φ has an arc shape corresponding to the arc detector array.

[0118] The left channel group, the right channel group, and the middle channel group located between the left and right channel groups can be predetermined along the channel direction.

[0119] For example, the left channel group, right channel group, and middle channel group can be determined based on the numbering order of the channels arranged in the channel direction. For instance, assuming the detector array has 768 channels in the channel direction, channels 1 to 50 can be determined as the left channel group, channels 411 to 460 as the middle channel group, and channels 719 to 768 as the right channel group.

[0120] The above exemplary descriptions illustrate typical examples of determining channel groups. Those skilled in the art will recognize that such descriptions are merely exemplary and are not intended to limit the scope of protection of the embodiments of the present invention.

[0121] In one implementation, the centroid of the average signal of each calibrated synthetic measurement signal detected by the intermediate channel group is determined, and the Z-position offset of the single-slot collimator is determined based on this centroid. Specifically, a first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group is determined; the centroid of the first average signal is determined; and the Z-position offset of the single-slot collimator is determined based on the centroid of the first average signal. The centroid of the first average signal lies in a coordinate system with the row number as the horizontal axis and the X-ray signal intensity as the vertical axis.

[0122] For example, suppose the intermediate channel group includes channels 411 to 460. Then, each of channels 411 to 460 can obtain its own... Figure 5 The calibrated synthetic measurement signal 90 is shown (in a coordinate system with row number as the horizontal axis and signal strength as the vertical axis). That is, the intermediate channel group can acquire a total of 50 signals, such as... Figure 5 The calibrated synthetic measurement signal 90 is shown (acquired from channels 411 to 460, respectively). These 50 are as follows... Figure 5The average value of the calibrated synthetic measurement signal 90 shown is the first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group. Based on the centroid of the first average signal and the fixed parameters of the CT system (such as the distance between the focal spot and the single-slot collimator, the distance between the focal spot and the rotation center (ISO), the actual slice width of the detector array, etc.), the Z position offset of the single-slot collimator can be determined.

[0123] As can be seen, the Z position offset of the single-slot collimator can be conveniently determined by the centroid of the first average signal formed by the intermediate channel group in the embodiment of the present invention.

[0124] In one implementation, the centroid of the average signal of the synthesized measurement signal detected by the left channel group and the centroid of the average signal of the synthesized measurement signal detected by the right channel group are determined, and the parallelism of the single-slot collimator is determined based on these two centroids. The parallelism of the single-slot collimator reflects the degree of parallelism between the outgoing light from the collimator and the mechanical axis of the collimator.

[0125] In one implementation, a second average signal of the calibrated composite measurement signal for each channel in the left channel group is determined; the centroid of the second average signal is determined; a third average signal of the calibrated composite measurement signal for each channel in the right channel group is determined; the centroid of the third average signal is determined; and the parallelism of the single-slot collimator is determined based on the centroids of the second and third average signals. The centroids of both the second and third average signals lie in a coordinate system with the row number as the horizontal axis and the X-ray signal intensity as the vertical axis.

[0126] For example, suppose the left channel group includes channels 1 to 50, and the right channel group includes channels 719 to 768. Then, each of channels 1 to 50 and channels 411 to 460 can obtain their respective... Figure 5 The calibrated synthetic measurement signal 90 is shown (in a coordinate system with row number as the horizontal axis and signal strength as the vertical axis). Specifically, the left channel group can acquire a total of 50 signals, such as... Figure 5 The calibrated synthetic measurement signal 90 shown is acquired from channels 1 to 50 respectively. The right-hand channel group can acquire a total of 50 signals, as shown below. Figure 5The calibrated synthetic measurement signals 90 shown are acquired from channels 719 to 768 respectively. The average value of the 50 synthetic measurement signals 90 acquired from the left channel group is the second average signal of the calibrated synthetic measurement signals for each channel in the left channel group. The average value of the 50 synthetic measurement signals 90 acquired from the right channel group is the third average signal of the calibrated synthetic measurement signals for each channel in the right channel group. Based on the centroid of the second average signal, the centroid of the third average signal, and the fixed parameters of the CT system (such as the total number of channels, the maximum channel number in the left channel group, and the maximum channel number in the right channel group, etc.), the parallelism of the single-slot collimator can be determined.

[0127] As can be seen, the parallelism of the single-slot collimator can be conveniently determined by the centroid of the second average signal formed by the left channel group and the centroid of the third average signal formed by the right channel group in the embodiment of the present invention.

[0128] In one implementation, the curvature of the single-slot collimator is determined based on the centroids of the second, third, and first average signals. When the curvature exceeds a predetermined curvature threshold, an alarm message prompting the replacement of the single-slot collimator is issued. The centroids of the first, second, and third average signals are all located in a coordinate system with the row number as the horizontal axis and the X-ray signal intensity as the vertical axis.

[0129] For example, suppose the middle channel group includes channels 411 to 460, the left channel group includes channels 1 to 50, and the right channel group includes channels 719 to 768. Then, each channel in the middle, left, and right channel groups can obtain its own... Figure 5 The calibrated synthetic measurement signal 90 is shown (in a coordinate system with row number as the horizontal axis and signal strength as the vertical axis).

[0130] The middle channel group can obtain a total of 50 such items. Figure 5 The calibrated synthetic measurement signal 90 shown is acquired from channels 411 to 460 respectively. The intermediate channel group acquired 50 signals as shown... Figure 5 The average value of the calibrated synthetic measurement signal 90 shown is the first average signal of the calibrated synthetic measurement signal of each channel in the middle channel group. The left channel group can acquire a total of 50 signals, such as... Figure 5 The calibrated synthetic measurement signal 90 shown is obtained from channels 1 to 50 respectively. The average value of the 50 synthetic measurement signals 90 obtained from the left channel group is the second average signal of the calibrated synthetic measurement signals of each channel in the left channel group. The right channel group can obtain a total of 50 signals as shown. Figure 5The calibrated synthetic measurement signal 90 shown is acquired from channels 719 to 768 respectively. The average value of the 50 synthetic measurement signals 90 acquired from the right channel group is the third average signal of the calibrated synthetic measurement signals of each channel in the right channel group.

[0131] Based on the centroids of the first average signal, the second average signal, the third average signal, and the fixed parameters of the CT system (such as the distance between the focal spot and the single-slot collimator, the distance between the focal spot and the ISO, the actual slice width of the detector array, the total number of channels, the maximum channel number in the left channel group and the maximum channel number in the right channel group, etc.), the curvature of the single-slot collimator can be determined.

[0132] As can be seen, the embodiments of the present invention can conveniently determine the curvature of a single-slot collimator based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal, and issue an alarm when the curvature exceeds the standard.

[0133] The implementation of this invention is described below with reference to specific algorithms.

[0134] In the channel direction, determine the left channel group L, the right channel group R, and the intermediate channel group M located between the left channel group L and the right channel group R. For example, L = 719:768; M = 411:460; R = 1:50. That is, the left channel group L includes channels 719 to 778, the right channel group R includes channels 1 to 50, and the intermediate channel group M includes channels 411 to 460.

[0135] First, the single-slot collimator moves a predetermined distance shift in one direction (e.g., the opposite direction of the Z-axis) from its initial position z-initial on the Z-axis, reaching the position initial–shift. At position initial–shift, the first air scan is performed, and the detector array acquires measurement data S. - (m, q, n), where m is the channel number, q is the row number, and n is the reading.

[0136] Then, the single-slot collimator returns from the initial-shift position to the initial position z-initial, and moves the same predetermined distance shift in the opposite direction of the Z-axis (e.g., the positive Z-axis), reaching the position initial+shift. At the position initial+shift, a second air scan is performed, and the detector array acquires measurement data S. + (m, q, n). Wherein, before the second air scan, the measurement data S acquired in the first air scan can be used... -(m, q, n) is pre-checked to ensure that the starting position z-initial is acceptable.

[0137] Next, merge S + (m, q, n) and S - (m, q, n) are used to obtain the synthesized measurement signal data. combine (m, q, n) and the synthetic air calibration signal aircal comibine (m, q, n). Where:

[0138]

[0139]

[0140] Where q' is the dividing point between the measurement data acquired in the first air scan and the measurement data acquired in the second air scan, and q' satisfies the following relationship:

[0141]

[0142]

[0143] Where N r N is the number of readings. M It is the number of channels contained in the intermediate group M.

[0144] Then, using the synthetic air calibration signal aircal combine (m, q, n) represents the synthesized measurement signal data combine The data (m, q, n) are calibrated, and the average value is taken over the reading n to obtain the calibrated synthetic measurement signal S′. comb (m, q). Where, when S + (m, q, n) and S - When (m, q, n) are represented by the logarithms of the X-ray intensities detected in their respective air scans, S′ comb (m, q) represents data. combine (m, q, n)-aircal combine (m, q, n) is the average value of (m, q, n) over the reading n; when S + (m, q, n) and S - When (m, q, n) are represented by the X-ray intensities detected in their respective air scans, S′ comb (m, q) represents data. combine (m, q, n) / aircal combine (m, q, n) is the average value of (m, q, n) over the reading n.

[0145] Next, S′ is matched according to the number of channels in each channel group. combThe average signal S of the left channel group L, the right channel group R, and the middle channel group M are calculated by averaging (m, q). L，M，R q ,in:

[0146]

[0147] Where N L，M，R These represent the number of channels in the left channel group L, the right channel group R, and the middle channel group M, respectively.

[0148] Then, the COG algorithm is used to calculate the centroids of the left channel group L, the right channel group R, and the middle channel group M, respectively. in:

[0149]

[0150] Q C Numbering is done around the center.

[0151] Then, the optimal Z position offset Z can be calculated. optimal ,in:

[0152]

[0153]

[0154] Where w is the actual layer width of the detector array, dFc is the distance between the focal spot and the single-slot collimator, dF is the distance between the focal spot and the rotation center (ISO), and z-initial is the starting position on the Z-axis.

[0155] Furthermore, parallelism can also be calculated. in:

[0156]

[0157]

[0158] Where M′ is the total number of channels, It is the largest channel number in the left channel group L. It is the largest channel number in the right channel group R.

[0159] and, The following conditions must be met:

[0160]

[0161] Where ΔZ Parallel It is the parallelism threshold value of a single-slot collimator.

[0162] Finally, the curvature can be calculated.

[0163] Furthermore, the calculated curvature should satisfy the following condition:

[0164]

[0165] Where ΔZ Curv is the threshold value for curvature.

[0166] As can be seen, compared with existing technologies that require at least multiple air measurements to adjust the tank position, the embodiments of the present invention can complete the tank adjustment through signal combination with only two air measurements, which is more efficient, simple, and convenient. In addition, due to the significant reduction in the number of air scans, the embodiments of the present invention can also save costs such as mechanical motors or control components.

[0167] Based on the above description, embodiments of the present invention also propose a collimator assembly adapted to the adjusted position. Figure 6 This is a first schematic diagram illustrating the adjustment of the target position of a single-slot collimator plate in a collimator assembly according to an embodiment of the present invention. The position of the collimator plate can be conveniently adjusted without the need for a mechanical motor or control components.

[0168] exist Figure 6 In the collimator assembly 20, the components include:

[0169] Frame 21, adapted to be arranged on rotating carrier 22;

[0170] A single-slot collimating plate 23 is arranged in the frame 21;

[0171] Rotation fulcrum 24 is fixed at the first end of frame 21;

[0172] Spring 25 is arranged between the opposite end of the first end of frame 21 and rotating carrier 22;

[0173] The single-slot collimator 23 includes a groove 26, and the frame 21 has rotational freedom about the pivot point 24. The single-slot collimator 23 is adapted to be moved to a target position based on the rotation process of the frame 21 about the pivot point 24 or the process of filling the shim in the groove 26, wherein the target position is determined by the method described above for determining the target position of the single-slot collimator.

[0174] The rotating carrier 22 can be implemented as a flange-like structure to provide fixed support for rotating components such as the X-ray tube, collimator assembly, and detector. The single-slot collimator 23 is preferably made of an X-ray shielding material of a high-density metal such as tungsten alloy.

[0175] When the control host is based on Figure 1After determining the target values ​​of the Z-position offset and parallelism of the single-slot collimator 23 using the method shown for determining the target position of the single-slot collimator 23, the rotation of the frame 21 around the pivot point 24 can be adjusted using the micrometer 40 coupled to the first end of the frame 21 so that the parallelism of the single-slot collimator 23 meets the target value. Once the parallelism of the single-slot collimator 23 reaches the target value, a shim of appropriate size is filled into the groove 26 so that the Z-position of the single-slot collimator 23 meets the Z-position offset. After adjusting the position of the single-slot collimator 23, the frame 21 can be fixed to the rotating carrier 22 using the four fixing bolts 29 on the frame 21. Preferably, a locating pin 28 is arranged on the frame 21 at the position aligned with the groove opening to fix the shim in the groove 26.

[0176] Preferably, in the frame 21, two parallel handles 27 are arranged at both ends of the single-slot collimator 23 along the Z-axis. The user can easily move the frame 21 using these two handles 27.

[0177] Based on the above description, embodiments of the present invention also propose another collimator assembly adapted to the adjusted position. Figure 7 This is a second schematic diagram illustrating the adjustment of the target position of a single-slot collimator plate in the collimator assembly according to an embodiment of the present invention. The position of the slot can be adjusted without the need for a mechanical motor or control components.

[0178] like Figure 7 As shown, the collimator assembly 30 includes:

[0179] The frame 31 is adapted to be arranged on a rotating carrier, and the frame 31 has a first groove 33 and a second groove 34 arranged parallel to each other along the Z-axis.

[0180] A single-slot collimating plate 37 is arranged in the frame 31;

[0181] The first spring 35, wherein the first end of the first spring 35 is fixed to the frame 31, and the second end of the first spring 35 is in contact with the side wall of the single-slot collimator 37.

[0182] The second spring 36, wherein the first end of the second spring 36 is fixed to the frame 31, and the second end of the second spring 36 is in contact with the side wall;

[0183] The first end of the single-slot collimator 37 has a degree of freedom of movement along the first slot 33, and the opposite end of the first end of the single-slot collimator 37 has a degree of freedom of movement along the second slot 34. The single-slot collimator 37 is adapted to be adjusted to a target position based on the combined movement of the first end of the single-slot collimator 37 along the first slot 33 and the opposite end of the first end of the single-slot collimator 37 along the second slot 34, the movement of the first end of the single-slot collimator 37 along the first slot 33, or the movement of the opposite end of the first end of the single-slot collimator 37 along the second slot 34. The target position is determined by the method described above for determining the target position of the single-slot collimator.

[0184] Frame 31 can be arranged on a rotating carrier. The rotating carrier can be implemented as a flange-like structure to provide fixed support for rotating components such as X-ray tubes, collimator assemblies, and detectors.

[0185] Example 1: When the control host is based on Figure 1 The method shown for determining the target position of the single-slot collimator determines the target values ​​of the Z position offset and parallelism of the single-slot collimator 37. When the user finds that the current parallelism of the single-slot collimator is equal to the target value, the user simultaneously adjusts the first micrometer 41 coupled to the first end of the single-slot collimator 37 and the second micrometer 42 coupled to the second end of the single-slot collimator 37 so that the single-slot collimator 37 maintains the parallelism and moves in the Z direction, and the Z position to which the single-slot collimator 37 moves conforms to the Z position offset.

[0186] Example 2: When the control host is based on Figure 1 The method shown for determining the target position of a single-slot collimator determines the target values ​​of the Z-position offset and parallelism of the single-slot collimator 37. If the user finds that the current parallelism of the single-slot collimator is not equal to the target value, the user can simultaneously adjust the first micrometer 41 coupled to the first end of the single-slot collimator 37 and the second micrometer 42 coupled to the second end of the single-slot collimator 37 so that the single-slot collimator 37 achieves the parallelism and moves in the Z direction, and the Z position to which the single-slot collimator 37 moves conforms to the Z-position offset.

[0187] Example 3: When the control host is based on Figure 1 The method shown for determining the target position of the single-slot collimator 37 determines the target values ​​of the Z position offset and parallelism of the single-slot collimator 37. If the user finds that the current parallelism of the single-slot collimator is not equal to the target value, the user can adjust the first micrometer 41 coupled to the first end of the single-slot collimator 37, or adjust the second micrometer 42 coupled to the second end of the single-slot collimator 37, so that the single-slot collimator 37 achieves the parallelism and moves in the Z direction, and the Z position to which the single-slot collimator 37 moves conforms to the Z position offset.

[0188] The above description illustrates a typical structure of a single-slot collimator assembly. Those skilled in the art will recognize that this description is merely illustrative and is not intended to limit the scope of protection of the embodiments of the present invention.

[0189] Based on the above description, the present invention also proposes a device for determining the target position of a single-slot collimator.

[0190] Figure 8 A structural diagram of an apparatus for determining the target position of a single-slot collimator according to an embodiment of the present invention.

[0191] like Figure 8 As shown, the device 800 includes:

[0192] The first acquisition module 801 is used to acquire the first measurement signal based on the first air scan when the single slot collimator moves a predetermined distance from the starting position along the first direction of the Z-axis to the first position.

[0193] The second acquisition module 802 is used to acquire a second measurement signal based on the second air scan when the single-slot collimator moves a predetermined distance from the starting position in the opposite direction of the first direction to the second position.

[0194] The first determining module 803 is used to determine the synthesized measurement signal and the synthesized air calibration signal based on the first measurement signal and the second measurement signal;

[0195] Calibration module 804 is used to calibrate the synthetic measurement signal using a synthetic air calibration signal;

[0196] The second determining module 805 is used to determine the target position of the single-slot collimator based on the calibrated synthetic measurement signal.

[0197] In one embodiment, the first determining module 803 is used to determine the boundary point between the first measurement signal and the second measurement signal; combine a first signal segment in the second measurement signal that extends from the boundary point along a first direction of the Z-axis and a second signal segment in the first measurement signal that extends from the boundary point in the opposite direction to form a composite measurement signal; and combine a third signal region in the first measurement signal that extends from the boundary point along the first direction of the Z-axis and a fourth signal segment in the second measurement signal that extends from the boundary point in the opposite direction to form a composite air calibration signal.

[0198] In one embodiment, the second determining module 805 is used to determine the centroid of the calibrated synthetic measurement signal and determine the target position of the single-slot collimator based on the centroid.

[0199] In one embodiment, the second determining module 805 is configured to determine the left channel group, the right channel group, and the intermediate channel group located between the left and right channel groups based on the channel numbering order; determine the first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group; determine the centroid of the first average signal; and determine the Z position offset of the single-slot collimator based on the centroid of the first average signal.

[0200] In one embodiment, the second determining module 805 is further configured to determine the second average signal of the calibrated synthetic measurement signal of each channel in the left channel group; determine the centroid of the second average signal; determine the third average signal of the calibrated synthetic measurement signal of each channel in the right channel group; determine the centroid of the third average signal; and determine the parallelism of the single-slot collimator based on the centroids of the second and third average signals.

[0201] In one embodiment, the second determining module 805 is further configured to determine the curvature of the single-slot collimator based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal.

[0202] In one embodiment, the device 800 further includes an alarm module 806, which issues an alarm message prompting the replacement of the single-slot collimator when the curvature exceeds a predetermined curvature threshold.

[0203] Based on the above description, the present invention also proposes a control host for a CT system.

[0204] Figure 9 This is a structural diagram of the control host of a CT system according to an embodiment of the present invention.

[0205] like Figure 9 As shown, the control host 900 includes a memory 901 and a processor 902, wherein the memory 901 stores an application program that can be executed by the processor 902, which is used to cause the processor 902 to execute the method described above for determining the target position of the single-slot collimator.

[0206] Specifically, the memory 901 can be implemented as various storage media such as electrically erasable programmable read-only memory (EEPROM), flash memory, and programmable programmable read-only memory (PROM). The processor 902 can be implemented as including one or more central processing units (CPUs) or one or more field-programmable gate arrays (FPGAs), wherein the FPGA integrates one or more CPU cores. Specifically, the CPU or CPU core can be implemented as a CPU, MCU, DSP, etc.

[0207] It should be noted that not all steps and modules in the above processes and structural diagrams are mandatory; some steps or modules can be omitted as needed. The execution order of the steps is not fixed and can be adjusted as required. The division of modules is merely for the convenience of description and functional division. In actual implementation, a module can be implemented by multiple modules, and the functions of multiple modules can also be implemented by the same module. These modules can be located in the same device or in different devices.

[0208] The hardware modules in each embodiment can be implemented mechanically or electronically. For example, a hardware module may include specially designed permanent circuitry or logic devices (such as dedicated processors, such as FPGAs or ASICs) to perform specific operations. A hardware module may also include programmable logic devices or circuitry (such as general-purpose processors or other programmable processors) temporarily configured by software to perform specific operations. The choice between mechanical implementation, dedicated permanent circuitry, or temporarily configured circuitry (such as software-configured circuitry) can be made based on cost and time considerations.

[0209] The present invention also provides a machine-readable storage medium storing instructions for causing a machine to perform the methods described herein. Specifically, a system or apparatus equipped with a storage medium storing software program code that implements the functions of any of the embodiments described above can be provided, and the computer (or CPU or MPU) of the system or apparatus can read and execute the program code stored in the storage medium. Furthermore, the operating system or the like operating on the computer can perform some or all of the actual operations through instructions based on the program code. The program code read from the storage medium can also be written to a memory located in an expansion board inserted into the computer or to a memory located in an expansion unit connected to the computer, and then the CPU or the like installed on the expansion board or expansion unit can execute some or all of the actual operations based on the instructions of the program code, thereby implementing the functions of any of the embodiments described above.

[0210] Storage media implementations for providing program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0211] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method (100) for determining the target position of a single-slot collimator, characterized in that, include: Acquire the first measurement signal (101) based on the first air scan when the single slot collimator moves a predetermined distance from the starting position along the first direction of the Z axis to the first position. Acquire a second measurement signal (102) based on the second air scan when the single-slot collimator moves a predetermined distance from the starting position in the opposite direction of the first direction to the second position. Based on the first and second measurement signals, the synthetic measurement signal and the synthetic air calibration signal are determined (103). The synthetic measurement signal (104) is calibrated using the synthetic air calibration signal. The target position (105) of the single-slot collimator is determined based on the calibrated synthetic measurement signal. The determination of the synthetic measurement signal and the synthetic air calibration signal (103) based on the first measurement signal and the second measurement signal includes: Determine the boundary point between the first measurement signal and the second measurement signal; The first signal segment of the second measurement signal, which extends from the dividing point along the first direction of the Z-axis, is combined with the second signal segment of the first measurement signal, which extends from the dividing point along the opposite direction, to form the composite measurement signal. The third signal region in the first measurement signal, which extends from the dividing point along the first direction of the Z-axis, is combined with the fourth signal segment in the second measurement signal, which extends from the dividing point along the opposite direction, to form the synthetic air calibration signal. The calibration of the synthetic measurement signal (104) using the synthetic air calibration signal includes: When both the first and second measurement signals are described by the logarithm of the X-ray intensities detected in their respective air scans, the composite air calibration signal is obtained by subtracting the composite air calibration signal from the composite measurement signal; or, When both the first and second measurement signals are described by the X-ray intensities detected in their respective air scans, the composite measurement signal is divided by the composite air calibration signal to obtain the calibrated composite air calibration signal.

2. The method (100) according to claim 1, characterized in that, The determination of the target position (105) of the single-slot collimator based on the calibrated synthetic measurement signal includes: Determine the centroid of the calibrated synthetic measurement signal; The target position of the single-slot collimator is determined based on the center of gravity.

3. The method (100) according to claim 2, characterized in that, The determination of the centroid of the calibrated synthetic measurement signal includes: The left channel group, the right channel group, and the middle channel group located between the left channel group and the right channel group are determined based on the channel numbering order. Determine the first average signal of the calibrated synthetic measurement signal for each channel in the intermediate channel group; Determine the centroid of the first average signal; The determination of the target position of the single-slot collimator based on the center of gravity includes: determining the Z position offset of the single-slot collimator based on the center of gravity of the first average signal.

4. The method (100) according to claim 3, characterized in that, The determination of the centroid of the calibrated synthetic measurement signal also includes: Determine the second average signal of the calibrated synthetic measurement signal for each channel in the left channel group; Determine the centroid of the second average signal; Determine the third average signal of the calibrated composite measurement signal for each channel in the right channel group; Determine the centroid of the third average signal; The method of determining the target position of the single-slot collimator based on the center of gravity further includes: determining the parallelism of the single-slot collimator based on the center of gravity of the second average signal and the center of gravity of the third average signal.

5. The method (100) according to claim 4, characterized in that, The method also includes: The curvature of the single-slot collimator is determined based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal. When the curvature exceeds a predetermined curvature threshold, an alarm message is issued prompting the replacement of the single-slot collimator.

6. A device (800) for determining the target position of a single-slot collimator, characterized in that, include: The first acquisition module (801) is used to acquire the first measurement signal based on the first air scan when the single slot collimator moves a predetermined distance from the starting position along the first direction of the Z axis to the first position. The second acquisition module (802) is used to acquire the second measurement signal based on the second air scan when the single slot collimator moves the predetermined distance from the starting position in the opposite direction of the first direction to the second position. The first determining module (803) is used to determine the synthesized measurement signal and the synthesized air calibration signal based on the first measurement signal and the second measurement signal; The calibration module (804) is used to calibrate the synthetic measurement signal using the synthetic air calibration signal; The second determining module (805) is used to determine the target position of the single-slot collimator based on the calibrated synthetic measurement signal. The first determining module (803) is further configured to: determine the boundary point between the first measurement signal and the second measurement signal; and combine the first signal segment in the second measurement signal that extends from the boundary point along the first direction of the Z-axis and the second signal segment in the first measurement signal that extends from the boundary point along the opposite direction to form the composite measurement signal; The third signal region in the first measurement signal, which extends from the dividing point along the first direction of the Z-axis, is combined with the fourth signal segment in the second measurement signal, which extends from the dividing point along the opposite direction, to form the synthetic air calibration signal. The calibration module (804) is further configured to: when both the first measurement signal and the second measurement signal are described by the logarithm of the X-ray intensity detected in their respective air scans, subtract the synthetic air calibration signal from the synthetic measurement signal to obtain a calibrated synthetic air calibration signal; or, When both the first and second measurement signals are described by the X-ray intensities detected in their respective air scans, the composite measurement signal is divided by the composite air calibration signal to obtain the calibrated composite air calibration signal.

7. The apparatus (800) according to claim 6, characterized in that, The second determining module (805) is used to determine the centroid of the calibrated synthetic measurement signal and determine the target position of the single-slot collimator based on the centroid.

8. The apparatus (800) according to claim 7, characterized in that, The second determining module (805) is used to determine the left channel group, the right channel group, and the intermediate channel group located between the left channel group and the right channel group based on the channel numbering order; and to determine the first average signal of the calibrated synthetic measurement signal of each channel in the intermediate channel group. Determine the centroid of the first average signal; determine the Z position offset of the single-slot collimator based on the centroid of the first average signal.

9. The apparatus (800) according to claim 8, characterized in that, The second determining module (805) is also used to determine the second average signal of the calibrated synthetic measurement signal of each channel in the left channel group; and to determine the centroid of the second average signal. Determine the third average signal of the calibrated composite measurement signal for each channel in the right channel group; Determine the centroid of the third average signal; The parallelism of the single-slot collimator is determined based on the centroids of the second and third average signals.

10. The apparatus (800) according to claim 9, characterized in that, The second determining module (805) is further configured to determine the curvature of the single-slot collimator based on the centroid of the second average signal, the centroid of the third average signal, and the centroid of the first average signal. The device (800) also includes: The alarm module (806) is used to issue an alarm message prompting the replacement of the single-slot collimator when the curvature is greater than a predetermined curvature threshold.

11. A collimator assembly (20, 30), characterized in that, include: The frame (21, 31) is adapted to be arranged on the rotating carrier (22); A single-slot collimating plate (23, 37) is arranged in the frame (21, 31); The pivot point (24) is fixed at the first end of the frame (21, 31); A spring (25) is arranged between the opposite ends of the first end of the frame (21, 31) and the rotating carrier (22); The single-slot collimator (23, 37) includes a groove (26), and the frame (21, 31) has rotational freedom about the pivot point (24); The single-groove aligning plate (23, 37) is adapted to be moved to a target position by a rotation process based on the frame (21, 31) about the pivot point (24) or by a process of filling a shim in the groove (26), wherein the target position is determined by the method as described in any one of claims 1 to 5.

12. A collimator assembly (20, 30), characterized in that, include: A frame (21, 31) is provided with a first groove (33) and a second groove (34) arranged parallel to each other along the Z-axis. A single-slot collimating plate (23, 37) is arranged in the frame (21, 31); The first spring (35) has its first end fixed to the frame (21, 31) and its second end in contact with the side wall of the single-slot collimator (23, 37). The second spring (36) has its first end fixed to the frame (21, 31) and its second end in contact with the side wall. The first end of the single-slot collimator (23, 37) has a degree of freedom of movement along the first slot (33), and the opposite end of the first end of the single-slot collimator (23, 37) has a degree of freedom of movement along the second slot (34); the single-slot collimator (23, 37) is adapted to be adjusted to a target position based on a combination of movement of the first end of the single-slot collimator (23, 37) along the first slot (33) and movement of the opposite end of the first end of the single-slot collimator (23, 37) along the second slot (34), movement of the first end of the single-slot collimator (23, 37) along the first slot (33), or movement of the opposite end of the first end of the single-slot collimator (23, 37) along the second slot (34); wherein the target position is determined by the method as described in any one of claims 1 to 5.

13. A control host (900) for a CT system, characterized in that, include: Memory (901); processor (902); wherein the memory (901) stores an application program that can be executed by the processor (902) for causing the processor (902) to perform a method (100) for determining the target position of a single-slot collimator as claimed in any one of claims 1 to 5.

14. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the method (100) for determining the target position of a single-slot collimator as described in any one of claims 1 to 5.

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