Method, apparatus and device for current modulation of a ct scanning system

Abstract

The CT scanning system current modulation method, device and equipment provided by the embodiments of the present disclosure comprise the following steps: determining the long axis and the short axis of the scanning phantom section at different scanning positions and the average equivalent diameter of the scanning phantom according to scanning data; determining the first exposure current of the ball tube at different scanning angles at each same scanning position according to the long axis and the short axis of the scanning phantom section at different scanning positions, the average equivalent diameter of the scanning phantom and an initial modulation coefficient; determining the second exposure current of the ball tube at different scanning times at each same scanning position according to the correlation between the scanning angle and the scanning time and the first exposure current; determining the current change rate of the ball tube at different scanning times at each same scanning position according to the second exposure current; and adjusting the initial modulation coefficient of the first exposure current at each scanning position according to the relationship between the current change rate of the ball tube at different scanning times at each same scanning position and the preset dose change rate of the ball tube.

Description

Technical Field

[0001] This invention relates to the field of scanning technology and related technical fields, specifically to a current modulation method, apparatus, and device suitable for a CT scanning system. Background Technology

[0002] In CT scanning technology, balancing the radiation dose from the X-ray tube with image quality is a core challenge. Traditional methods modulate the tube current (mA) based on patient body shape information or image noise level in the localization image to achieve radiation dose control. However, in high-speed scanning scenarios (such as cardiac CT angiography), the X-ray tube's own dose adjustment capability cannot match the theoretically calculated current requirements in real time. This contradiction can lead to a significant deviation between the exposure current and the theoretical value. Without a matching algorithm, the phase difference can reach 90°, causing spatial misalignment between low-current and high-current exposure areas.

[0003] Existing technologies mostly rely on static or quasi-dynamic parameters (such as patient body size and localization image attenuation curves) for dose prediction, but do not mention the handling of high-speed scanning or the handling of certain patients with special body types.

[0004] Therefore, given the problems with existing technologies, there is an urgent need for a fast-response current modulation method to ensure that the modulation current can conform to the patient's body shape and, under extreme conditions, provide a reasonable theoretical current value within the dose adjustment capability of the X-ray tube. Summary of the Invention

[0005] The embodiments described herein provide a current modulation method, apparatus, and device for a CT scanning system, addressing problems existing in the prior art.

[0006] In a first aspect, according to the present disclosure, a current modulation method for a CT scanning system is provided, comprising:

[0007] Acquire scanning data of the scanning phantom, and based on the scanning data, determine the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom;

[0008] Based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at the same scanning positions is determined.

[0009] Based on the relationship between scanning angle and scanning time and the first exposure current, the second exposure current of the X-ray tube at different scanning times at the same scanning position is determined.

[0010] Based on the second exposure current, determine the rate of change of the X-ray tube current at different scanning times at the same scanning positions;

[0011] Based on the relationship between the rate of change of X-ray tube current and the rate of change of preset dose of X-ray tube at different scanning times at the same scanning positions, the initial modulation coefficient of the first exposure current at each scanning position is adjusted to obtain the target modulation coefficient of the first exposure current of X-ray tube at each scanning position.

[0012] In some embodiments of this disclosure, determining the major and minor axes of the scanned phantom cross-section at different scanning positions, and the average equivalent diameter of the scanned phantom, based on the scanned data, includes:

[0013] Based on the scan data, the first scan data of the scanning phantom at different scan positions under the first scan angle is determined, and the second scan data of the scanning phantom at different scan positions under the second scan angle is determined, wherein the first scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is perpendicular to the scanning bed, and the second scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is parallel to the scanning bed.

[0014] Based on the first scan data of the scanned model at different scan positions under the first scan angle, the minor axis of the scanned model cross section at different scan positions is determined;

[0015] Based on the second scanning data of the scanning model at different scanning positions under the second scanning angle, the major axis of the scanning model cross section at different scanning positions is determined;

[0016] The average equivalent diameter of the scanned phantom is determined by the major and minor axes of the cross-section of the scanned phantom at different scanning positions.

[0017] In some embodiments of this disclosure, determining the first exposure current of the X-ray tube at different scanning angles at the same scanning positions, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, includes:

[0018] Based on the major and minor axes of the scanned phantom cross section at different scanning positions, the path of X-rays passing through the scanned phantom cross section at different scanning angles at the same scanning positions is determined.

[0019] Based on the path of X-rays through the cross section of the scanning phantom at different scanning angles at the same scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at the same scanning positions is determined.

[0020] In some embodiments of this disclosure, the scanning angle at the z-scan position is At that time, the path of the X-rays passing through the cross-section of the scanning phantom satisfies:

[0021]

[0022] in, This indicates the major axis of the scanned phantom section at the z-scan position. This indicates the minor axis of the scanned phantom section at the z-scan position. The scanning angle;

[0023] The scanning angle at the z-scan position is... At that time, the first exposure current of the X-ray tube satisfies:

[0024]

[0025] in, As the reference current, The attenuation coefficient of the scanning phantom is... The average equivalent diameter of the scanning phantom. These are the initial modulation coefficients.

[0026] In some embodiments of this disclosure, determining the rate of change of X-ray tube current at different scan times at the same scan position based on the second exposure current includes:

[0027] Based on the second exposure current, the derivative of the second exposure current with respect to time is calculated to obtain the rate of change of the X-ray tube current at different scanning times at the same scanning positions.

[0028] In some embodiments of this disclosure, adjusting the initial modulation coefficient of the first exposure current at each scanning position based on the relationship between the rate of change of the X-ray tube current and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position, includes:

[0029] The actual dose change rate of the X-ray tube at different scanning times at different scanning positions is determined based on the rate of change of the X-ray tube current at different scanning times at different scanning positions.

[0030] Based on the relationship between the actual dose change rate of the X-ray tube and the preset dose change rate at different scan times at the same scan position, when the actual dose change rate of the X-ray tube at the target scan position is greater than the preset dose change rate for at least one target scan time, the initial modulation coefficient of the first exposure current corresponding to the target scan time at the target scan position is adjusted to obtain the target modulation coefficient of the first exposure current of the X-ray tube at the target scan position.

[0031] In some embodiments of this disclosure, the method further includes:

[0032] Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions Determine the scanning time interval corresponding to each scanning position;

[0033] When the major axis difference information corresponding to two adjacent scanning positions is greater than the preset difference information, and / or the minor axis difference information is greater than the preset difference information, the scanning time interval corresponding to the two adjacent scanning positions is divided into three sub-scanning time intervals according to the scanning time interval corresponding to the two adjacent scanning positions, and the third sub-scanning time interval corresponding to the previous scanning position and the first sub-scanning time interval corresponding to the next scanning position are used as transition time intervals.

[0034] Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval.

[0035] In some embodiments of this disclosure, the major axis of the transition time interval satisfies:

[0036]

[0037] The minor axis of the transition time interval satisfies:

[0038]

[0039] in, This is the major axis of the cross-section of the scanning phantom corresponding to the next scanning position. This is the minor axis of the cross-section of the scanning phantom corresponding to the next scanning position. , , g represents the values ​​of two adjacent scan positions. , This is the collimator aperture distance. For pitch, The rotational speed of the frame, The minimum interval time for calculating the first exposure current within the CT scanning system is a fixed value.

[0040] Secondly, according to the present disclosure, a current modulation device for a CT scanning system is provided, comprising:

[0041] The data determination module is used to acquire the scanning data of the scanning model and, based on the scanning data, determine the major and minor axes of the cross-section of the scanning model at different scanning positions, as well as the average equivalent diameter of the scanning model.

[0042] The first exposure current determination module is used to determine the first exposure current of the X-ray tube at different scanning angles at the same scanning positions based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient.

[0043] The second exposure current determination module is used to determine the second exposure current of the X-ray tube at different scanning times at the same scanning positions based on the correlation between the scanning angle and the scanning time and the first exposure current.

[0044] The current change rate determination module is used to determine the current change rate of the X-ray tube at different scanning times at the same scanning positions based on the second exposure current.

[0045] The correction module is used to adjust the initial modulation coefficient of the first exposure current at each scanning position based on the relationship between the rate of change of the X-ray tube current and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, so as to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position.

[0046] Thirdly, according to the present disclosure, a computer device is provided, comprising:

[0047] One or more processors;

[0048] Storage device for storing one or more programs.

[0049] When the one or more programs are executed by the one or more processors, the one or more processors perform the method as described in any of the first aspects.

[0050] The CT scanning system current modulation method, apparatus, and device provided in this disclosure first acquire scanning data of a scanning phantom, and determine the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom, based on the scanning data. Then, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, determine the first exposure current of the X-ray tube at different scanning angles at each same scanning position. Based on the correlation between the scanning angle and the scanning time and the first exposure current, determine the second exposure current of the X-ray tube at different scanning times at each same scanning position. Based on the second exposure current, determine the current change rate of the X-ray tube at different scanning times at each same scanning position. Finally, based on the relationship between the current change rate of the X-ray tube at different scanning times at each same scanning position and the preset dose change rate of the X-ray tube, adjust the initial modulation coefficient of the first exposure current at each scanning position to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position. By adjusting the initial modulation coefficient of the first exposure current at the scanning angle of the scanning position where the actual dose change rate is greater than the preset dose change rate, it is ensured that in actual scanning application scenarios, at different scanning angles at each scanning position, the actual dose change rate of the X-ray tube is less than the preset dose change rate, and the actual dose change rate of the X-ray tube and the theoretical dose change rate of the X-ray tube can be matched. According to the X-ray tube capability, current modulation is applied to scanning phantoms of different shapes, and there will be no unplanned current curve distribution, ensuring that the current change of the current modulation algorithm is within a controllable range.

[0051] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. It should be understood that the drawings described below only relate to some embodiments of this disclosure and are not intended to limit this disclosure, wherein:

[0053] Figure 1 This is a schematic flowchart of a current modulation method for a CT scanning system provided in an embodiment of this disclosure;

[0054] Figure 2 This is a schematic diagram of the structure of a current modulation device for a CT scanning system provided in an embodiment of this disclosure;

[0055] Figure 3 This is a schematic diagram of the structure of a computer device provided in an embodiment of this disclosure.

[0056] In the accompanying diagram, markers with the same last two digits correspond to the same elements. It should be noted that the elements in the diagram are schematic and not drawn to scale. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are also within the scope of protection of this disclosure.

[0058] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this subject matter pertains. It will be further understood that terms such as those defined in commonly used dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the specification and in the relevant art, and shall not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, the statement of “connecting” or “coupling” two or more parts together shall mean that these parts are directly joined together or joined through one or more intermediate components.

[0059] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0060] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists, A and B exist simultaneously, or B exists. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0061] Furthermore, in all embodiments of this disclosure, terms such as “first” and “second” are used only to distinguish one component (or part of a component) from another component (or another part of a component).

[0062] In the description of this application, unless otherwise stated, "multiple" means two or more (including two), and similarly, "multiple groups" means two or more (including two groups).

[0063] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0064] In view of the problems existing in the prior art, this disclosure provides a current modulation method for a CT scanning system. Figure 1 This is a schematic flowchart of a current modulation method for a CT scanning system provided in an embodiment of this disclosure, as shown below. Figure 1 As shown, the current modulation method of the CT scanning system includes:

[0065] S110. Obtain the scanning data of the scanning phantom, and based on the scanning data, determine the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom.

[0066] Specifically, the scanning data of the scanning phantom is first obtained. After obtaining the scanning data, the three-dimensional image information of the scanning phantom is obtained by modeling the scanning data. Then, based on the three-dimensional image information of the scanning phantom, the cross-sectional information of the scanning phantom at different scanning positions can be determined. According to the cross-sectional information of the scanning phantom at different scanning positions, the major axis and minor axis of the cross-section of the scanning phantom at different scanning positions can be determined.

[0067] In the specific implementation, based on the scanning data, the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom, are determined. This includes: determining the first scanning data of the scanning phantom at different scanning positions under a first scanning angle, and determining the first scanning data of the scanning phantom at different scanning positions under a second scanning angle, wherein the first scanning angle is the scanning angle corresponding to when the X-ray from the X-ray tube is perpendicular to the scanning bed, and the second scanning angle is the scanning angle corresponding to when the X-ray from the X-ray tube is parallel to the scanning bed; determining the minor axis of the scanning phantom cross-section at different scanning positions based on the first scanning data of the scanning phantom at the first scanning angle; determining the major axis of the scanning phantom cross-section at different scanning positions based on the second scanning data of the scanning phantom at the second scanning angle; and determining the average equivalent diameter of the scanning phantom based on the major and minor axes of the scanning phantom cross-section at different scanning positions.

[0068] Specifically, the cross-section of the scanning phantom at different scanning positions is elliptical. Along the scanning bed direction, first scanning data at different scanning positions under the first scanning angle and second scanning data at different scanning positions under the second scanning angle are acquired respectively. Then, based on the first scanning data at different scanning positions under the first scanning angle, the minor axis of the scanning phantom at different scanning positions can be determined. Based on the second scanning data at different scanning positions under the second scanning angle, the major axis of the scanning phantom at different scanning positions can be determined. Then, based on the relationship between the major axis and the scanning position, and the relationship between the minor axis and the scanning position, the major axis and minor axis of the cross-section of the scanning phantom at each scanning position are determined.

[0069] After obtaining the major and minor axes of the scanned phantom cross-section at each scanning position, the average equivalent diameter of the scanned phantom satisfies:

[0070]

[0071] in, To represent the major axis of the scanned phantom section at the z-scan position, This indicates the minor axis of the scanned phantom section at the z-scan position.

[0072] S120. Based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, determine the first exposure current of the X-ray tube at different scanning angles at the same scanning positions.

[0073] In a specific implementation, the first exposure current of the X-ray tube at different scanning angles at different scanning positions is determined based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient. This includes: determining the path of X-rays passing through the scanning phantom cross-section at different scanning angles at different scanning positions based on the major and minor axes of the scanning phantom cross-section at different scanning positions; and determining the first exposure current of the X-ray tube at different scanning angles at different scanning positions based on the path of X-rays passing through the scanning phantom cross-section at different scanning angles at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient.

[0074] Specifically, at the z-scan position and the scan angle is At that time, the path of the X-rays passing through the cross-section of the scanning phantom satisfies:

[0075]

[0076] in, This indicates the major axis of the scanned phantom section at the z-scan position. This indicates the minor axis of the scanned phantom section at the z-scan position. For scanning angle, 0≤ .

[0077] The scanning angle at the z-scan position is... At that time, the first exposure current of the X-ray tube satisfies:

[0078]

[0079] in, As the reference current, The attenuation coefficient of the scanning phantom is... The average equivalent diameter of the scanning phantom. This represents the initial modulation coefficient, which is 1 by default.

[0080] S130. Based on the relationship between scanning angle and scanning time and the first exposure current, determine the second exposure current of the X-ray tube at different scanning times at the same scanning positions.

[0081] Considering both axial scanning and helical scanning for a full revolution, the scanning angle in the first exposure current during one normal rotation is... Replacing it with the scan time t, that is, the relationship between the scan angle and the scan time satisfies:

[0082]

[0083] in, For scan time, The rotational speed of the frame.

[0084] That is, the scanning angle at the z-scan position is At that time, the second exposure current of the X-ray tube satisfies:

[0085]

[0086] S140. Based on the second exposure current, determine the rate of change of the X-ray tube current at different scanning times at the same scanning positions.

[0087] After obtaining the second exposure current, the derivative of the second exposure current with respect to time for one normal rotation is taken. The rate of change of X-ray tube current at different scanning times was obtained.

[0088] S150. Based on the relationship between the rate of change of X-ray tube current and the preset dose change rate of X-ray tube at different scanning times at the same scanning positions, the initial modulation coefficient of the first exposure current at each scanning position is adjusted to obtain the target modulation coefficient of the first exposure current of X-ray tube at each scanning position.

[0089] After obtaining the current change rate of the X-ray tube at different scanning times at each same scanning position in step S140, the current change rate of the X-ray tube at different scanning times at each same scanning position is converted into the actual dose change rate of the X-ray tube. Then, the actual dose change rate of the X-ray tube at different scanning times at the same scanning position is compared with the preset dose change rate of the X-ray tube. When the actual dose change rate of the X-ray tube at the target scanning position for at least one scanning time is greater than the preset dose change rate, the scanning angle is first determined based on the scanning time. Then, the initial modulation coefficient of the first exposure current in the scanning angle at the target scanning position is adjusted to ensure that the actual dose change rate of the X-ray tube for the target scanning time corresponding to the scanning angle is less than the preset dose change rate.

[0090] In the specific implementation, based on the relationship between the current change rate of the X-ray tube at different scanning times at each same scanning position and the preset dose change rate of the X-ray tube, the initial modulation coefficient of the first exposure current at each scanning position is adjusted to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position. This includes: determining the actual dose change rate of the X-ray tube at different scanning times at each same scanning position based on the current change rate of the X-ray tube at different scanning times at each same scanning position; and adjusting the initial modulation coefficient of the first exposure current corresponding to the target scanning time at the target scanning position when the actual dose change rate of the X-ray tube at at least one target scanning time at the target scanning position is greater than the preset dose change rate, based on the relationship between the actual dose change rate of the X-ray tube at different scanning times at each same scanning position and the preset dose change rate, to obtain the target modulation coefficient of the first exposure current of the X-ray tube at the target scanning position.

[0091] It should be noted that in the above implementation process, the preset dose change rate of the X-ray tube is different in different current ranges. Therefore, the preset dose change rate of the X-ray tube is different at different scanning times.

[0092] By adjusting the initial modulation coefficient of the first exposure current at the scanning angle of the scanning position where the actual dose change rate is greater than the preset dose change rate, it is ensured that in actual scanning application scenarios, at different scanning angles at each scanning position, the actual dose change rate of the X-ray tube is less than the preset dose change rate, and the actual dose change rate of the X-ray tube and the theoretical dose change rate of the X-ray tube can be matched. According to the X-ray tube capability, current modulation is applied to scanning phantoms of different shapes, and there will be no unplanned current curve distribution, ensuring that the current change of the current modulation algorithm is within a controllable range.

[0093] After determining the target modulation coefficient of the first exposure current of the X-ray tube at different scanning angles at each scanning position, the target modulation coefficient of the first exposure current of the X-ray tube at different scanning angles at each scanning position is sent to the control module. This enables the control module to control the first exposure current of the X-ray tube based on the target modulation coefficient of the first exposure current of the X-ray tube at different scanning angles at each scanning position when scanning the scanning module.

[0094] The CT scanning system current modulation method provided in this embodiment first acquires scanning data of a scanning phantom, and determines the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom, based on the scanning data. Then, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at each same scanning position is determined. Based on the correlation between the scanning angle and the scanning time and the first exposure current, the second exposure current of the X-ray tube at different scanning times at each same scanning position is determined. Based on the second exposure current, the current change rate of the X-ray tube at different scanning times at each same scanning position is determined. Finally, based on the relationship between the current change rate of the X-ray tube at different scanning times at each same scanning position and the preset dose change rate of the X-ray tube, the initial modulation coefficient of the first exposure current at each scanning position is adjusted to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position. By adjusting the initial modulation coefficient of the first exposure current at the scanning angle of the scanning position where the actual dose change rate is greater than the preset dose change rate, it is ensured that in actual scanning application scenarios, at different scanning angles at each scanning position, the actual dose change rate of the X-ray tube is less than the preset dose change rate, and the actual dose change rate of the X-ray tube and the theoretical dose change rate of the X-ray tube can be matched. According to the X-ray tube capability, current modulation is applied to scanning phantoms of different shapes, and there will be no unplanned current curve distribution, ensuring that the current change of the current modulation algorithm is within a controllable range.

[0095] Based on the above embodiments, the improved CT scanning system current modulation method of this disclosure further includes: based on the pitch, collimator opening distance, gantry rotation speed, and two adjacent scanning positions... The scanning time interval corresponding to each scanning position is determined. When the major axis difference information corresponding to two adjacent scanning positions is greater than the preset difference information, and / or the minor axis difference information is greater than the preset difference information, the scanning time interval corresponding to two adjacent scanning positions is divided into three sub-scanning time intervals according to the scanning time intervals corresponding to two adjacent scanning positions, and the third sub-scanning time interval corresponding to the previous scanning position and the first sub-scanning time interval corresponding to the next scanning position are used as transition time intervals. Based on the pitch, collimator opening distance, frame rotation speed, and the distance between two adjacent scanning positions... The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval.

[0096] Specifically, after the above steps S110, S120, S130, S140 and S150 are completed, and the target modulation coefficients corresponding to different scanning angles at each scanning position are determined, in the application scenario of helical scanning, it is necessary to determine whether the actual dose change rate of the X-ray tube during the process of switching from the previous scanning position to the next scanning position matches the theoretical dose change rate of the X-ray tube.

[0097] In practical applications, if the difference in the major axis of the scanning phantom cross-sections corresponding to two adjacent scanning positions is greater than a preset difference, and / or the difference in the minor axis is greater than a preset difference, the actual dose change rate of the X-ray tube during the transition from the previous scanning position to the next scanning position may not match the theoretical dose change rate of the X-ray tube. In this case, the actual dose change rate of the X-ray tube may not match the theoretical dose change rate of the X-ray tube, based first on the pitch, collimator opening distance, gantry rotation speed, and the difference in the major axis of the scanning phantom cross-sections corresponding to two adjacent scanning positions. First, determine the scanning time interval corresponding to each scanning position. Then, based on the scanning time intervals corresponding to two adjacent scanning positions, divide the scanning time intervals between two adjacent scanning positions into three sub-scanning time intervals. Use the third sub-scanning time interval corresponding to the previous scanning position and the first sub-scanning time interval corresponding to the next scanning position as a transition time interval. Finally, based on the pitch, collimator opening distance, frame rotation speed, and the time intervals between two adjacent scanning positions... The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval.

[0098] The scan time interval corresponding to the scan position satisfies:

[0099]

[0100] The major axis of the transition time interval satisfies:

[0101]

[0102] The minor axis of the transition time interval satisfies:

[0103]

[0104] in, This is the major axis of the cross-section of the scanning phantom corresponding to the next scanning position. This is the minor axis of the cross-section of the scanning phantom corresponding to the next scanning position. , , g represents the values ​​of two adjacent scan positions. , This is the collimator aperture distance. For pitch, The rotational speed of the frame, The minimum interval time for calculating the first exposure current within the CT scanning system is a fixed value.

[0105] That is, if the scanning positions include four positions: z-2, z-1, z, and z+1, the z-2 scanning position and the z-1 scanning position... The difference between the z-scan position and the minor axis is less than or equal to the preset difference information. The difference between the z-1 scan position and the z-scan position is less than or equal to the preset difference information. The differences are all greater than the preset difference. In practical applications, the actual dose change rate of the X-ray tube may not match the theoretical dose change rate during the switch from the z-1 scan position to the z scan position. In this case, it is necessary to adjust the dose change rate during the switch from the z-1 scan position to the z scan position. Adjust the short axis.

[0106] In the specific adjustment process, firstly, based on the pitch, collimator opening distance, frame rotation speed, and the area interval information of the z-1 scan position, the scanning time interval corresponding to the z-1 scan position and the z-scan position are determined. Then, based on the scanning time intervals corresponding to the z-1 and z-scan positions, these intervals are divided into three sub-scanning time intervals. The third sub-scanning time interval corresponding to the z-1 scan position and the first sub-scanning time interval corresponding to the z-scan position are used as transition time intervals. Furthermore, based on the pitch, collimator opening distance, frame rotation speed, and the area interval information of two adjacent scan positions... The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval. Finally, in the actual scanning scenario, the transition major and minor axes are used as the major and minor axes of the first exposure current of the X-ray tube in the transition time interval, and the calculated first exposure current is sent to the X-ray tube.

[0107] By proposing a transition time interval and changing the major and minor axes of the scanning phantom cross-section within the transition time interval, it is ensured that in practical applications, if the difference in the major axis of the scanning phantom cross-section corresponding to two adjacent scanning positions is greater than a preset difference, and / or the difference in the minor axis is greater than a preset difference, the actual dose change rate of the X-ray tube during the transition from the previous scanning position to the next scanning position will match the theoretical dose change rate of the X-ray tube.

[0108] Based on the above embodiments, this disclosure also provides a current modulation device for a CT scanning system. Figure 2 This is a schematic diagram of the structure of a current modulation device for a CT scanning system provided in an embodiment of this disclosure, as shown below. Figure 2 As shown, the current modulation device of the CT scanning system includes:

[0109] The data determination module 210 is used to acquire the scanning data of the scanning phantom and, based on the scanning data, determine the major axis and minor axis of the cross section of the scanning phantom at different scanning positions, as well as the average equivalent diameter of the scanning phantom.

[0110] The first exposure current determination module 220 is used to determine the first exposure current of the X-ray tube at different scanning angles at the same scanning positions based on the major and minor axes of the scanning model cross-section at different scanning positions, the average equivalent diameter of the scanning model, and the initial modulation coefficient.

[0111] The second exposure current determination module 230 is used to determine the second exposure current of the X-ray tube at different scanning times at the same scanning positions based on the correlation between the scanning angle and the scanning time and the first exposure current.

[0112] The current change rate determination module 240 is used to determine the current change rate of the X-ray tube at different scanning times at the same scanning positions based on the second exposure current.

[0113] The correction module 250 is used to adjust the initial modulation coefficient of the first exposure current at each scanning position according to the relationship between the current change rate of the X-ray tube and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, so as to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position.

[0114] The CT scanning system current modulation device provided in this embodiment first acquires scanning data of a scanning phantom, and determines the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom, based on the scanning data. Then, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, it determines the first exposure current of the X-ray tube at different scanning angles at the same scanning positions. Based on the correlation between the scanning angle and the scanning time and the first exposure current, it determines the second exposure current of the X-ray tube at different scanning times at the same scanning positions. Based on the second exposure current, it determines the current change rate of the X-ray tube at different scanning times at the same scanning positions. Finally, based on the relationship between the current change rate of the X-ray tube at different scanning times at the same scanning positions and the preset dose change rate of the X-ray tube, it adjusts the initial modulation coefficient of the first exposure current at each scanning position to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position. By adjusting the initial modulation coefficient of the first exposure current at the scanning angle of the scanning position where the actual dose change rate is greater than the preset dose change rate, it is ensured that in actual scanning application scenarios, at different scanning angles at each scanning position, the actual dose change rate of the X-ray tube is less than the preset dose change rate, and the actual dose change rate of the X-ray tube and the theoretical dose change rate of the X-ray tube can be matched. According to the X-ray tube capability, current modulation is applied to scanning phantoms of different shapes, and there will be no unplanned current curve distribution, ensuring that the current change of the current modulation algorithm is within a controllable range.

[0115] In some embodiments of this disclosure, determining the major and minor axes of the scanned phantom cross-section at different scanning positions, and the average equivalent diameter of the scanned phantom, based on the scanned data, includes:

[0116] Based on the scan data, the first scan data of the scanning phantom at different scan positions under the first scan angle is determined, and the second scan data of the scanning phantom at different scan positions under the second scan angle is determined, wherein the first scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is perpendicular to the scanning bed, and the second scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is parallel to the scanning bed.

[0117] Based on the first scan data of the scanned model at different scan positions under the first scan angle, the minor axis of the scanned model cross section at different scan positions is determined;

[0118] Based on the second scanning data of the scanning model at different scanning positions under the second scanning angle, the major axis of the scanning model cross section at different scanning positions is determined;

[0119] The average equivalent diameter of the scanned phantom is determined by the major and minor axes of the cross-section of the scanned phantom at different scanning positions.

[0120] In some embodiments of this disclosure, determining the first exposure current of the X-ray tube at different scanning angles at the same scanning positions, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, includes:

[0121] Based on the major and minor axes of the scanned phantom cross section at different scanning positions, the path of X-rays passing through the scanned phantom cross section at different scanning angles at the same scanning positions is determined.

[0122] Based on the path of X-rays through the cross section of the scanning phantom at different scanning angles at the same scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at the same scanning positions is determined.

[0123] In some embodiments of this disclosure, at the z-scan position and the scan angle is At that time, the path of the X-rays passing through the cross-section of the scanning phantom satisfies:

[0124]

[0125] in, This indicates the major axis of the scanned phantom section at the z-scan position. This indicates the minor axis of the scanned phantom section at the z-scan position. The scanning angle;

[0126] The scanning angle at the z-scan position is... At that time, the first exposure current of the X-ray tube satisfies:

[0127]

[0128] in, As the reference current, The attenuation coefficient of the scanning phantom is... The average equivalent diameter of the scanning phantom. These are the initial modulation coefficients.

[0129] In some embodiments of this disclosure, determining the rate of change of X-ray tube current at different scan times at the same scan position based on the second exposure current includes:

[0130] Based on the second exposure current, the derivative of the second exposure current with respect to time is calculated to obtain the rate of change of the X-ray tube current at different scanning times at the same scanning positions.

[0131] In some embodiments of this disclosure, adjusting the initial modulation coefficient of the first exposure current at each scanning position based on the relationship between the rate of change of the X-ray tube current and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position, includes:

[0132] The actual dose change rate of the X-ray tube at different scanning times at different scanning positions is determined based on the rate of change of the X-ray tube current at different scanning times at different scanning positions.

[0133] Based on the relationship between the actual dose change rate of the X-ray tube and the preset dose change rate at different scan times at the same scan position, when the actual dose change rate of the X-ray tube at the target scan position is greater than the preset dose change rate for at least one target scan time, the initial modulation coefficient of the first exposure current corresponding to the target scan time at the target scan position is adjusted to obtain the target modulation coefficient of the first exposure current of the X-ray tube at the target scan position.

[0134] In some embodiments of this disclosure, the method further includes:

[0135] Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions Determine the scanning time interval corresponding to each scanning position;

[0136] When the major axis difference information corresponding to two adjacent scanning positions is greater than the preset difference information, and / or the minor axis difference information is greater than the preset difference information, the scanning time interval corresponding to the two adjacent scanning positions is divided into three sub-scanning time intervals according to the scanning time interval corresponding to the two adjacent scanning positions, and the third sub-scanning time interval corresponding to the previous scanning position and the first sub-scanning time interval corresponding to the next scanning position are used as transition time intervals.

[0137] Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval.

[0138] In some embodiments of this disclosure, the major axis of the transition time interval satisfies:

[0139]

[0140] The minor axis of the transition time interval satisfies:

[0141]

[0142] in, This is the major axis of the cross-section of the scanning phantom corresponding to the next scanning position. This is the minor axis of the cross-section of the scanning phantom corresponding to the next scanning position. , , g represents the values ​​of two adjacent scan positions. , The distance between the collimation openings of the X-ray tube is denoted as . For pitch, The rotational speed of the X-ray tube. The minimum interval time for calculating the first exposure current within the CT scanning system is a fixed value.

[0143] This application also provides a computer device, please refer to the following for details. Figure 3 , Figure 3 This is a basic structural block diagram of the computer device in this embodiment.

[0144] The computer device includes a memory 510 and a processor 520 that are interconnected via a system bus. It should be noted that only a computer device with components 510-520 is shown in the figure; however, it should be understood that it is not required to implement all the shown components, and more or fewer components may be implemented alternatively. Those skilled in the art will understand that the computer device described herein is a device capable of automatically performing numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes, but is not limited to, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0145] Computer devices can include desktop computers, laptops, handheld computers, and cloud servers. These devices allow for human-computer interaction with users through keyboards, mice, remote controls, touchpads, or voice-activated devices.

[0146] The memory 510 includes at least one type of readable storage medium, including non-volatile memory or volatile memory, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, etc. RAM may include static RAM or dynamic RAM. In some embodiments, the memory 510 may be an internal storage unit of a computer device, such as the hard disk or memory of the computer device. In other embodiments, the memory 510 may also be an external storage device of the computer device, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, or flash card equipped on the computer device. Of course, the memory 510 may include both internal storage units and external storage devices of the computer device. In this embodiment, the memory 510 is typically used to store the operating system and various application software installed on the computer device, such as the program code of the method described above. In addition, the memory 510 may also be used to temporarily store various types of data that have been output or will be output.

[0147] The processor 520 is typically used to perform the overall operation of a computer device. In this embodiment, the memory 510 is used to store program code or instructions, including computer operation instructions. The processor 520 is used to execute the program code or instructions stored in the memory 510 or to process data, such as program code that runs the methods described above.

[0148] In this article, the bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. This bus system can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0149] Another embodiment of this application also provides a computer-readable medium, which may be a computer-readable signal medium or a computer-readable medium. A processor in a computer reads computer-readable program code stored in the computer-readable medium, enabling the processor to execute the functional actions specified in each step or combination of steps in the above method; and to generate means for implementing the functional actions specified in each block or combination of blocks in the block diagram.

[0150] Computer-readable media include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared memory or semiconductor systems, devices or apparatuses, or any suitable combination thereof, wherein the memory is used to store program code or instructions, the program code including computer operation instructions, and the processor is used to execute the program code or instructions of the above-described methods stored in the memory.

[0151] The definitions of memory and processor can be found in the description of the foregoing computer device embodiments, and will not be repeated here.

[0152] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0153] In the various embodiments of this application, the functional units or modules can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0154] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0155] Unless otherwise expressly indicated by the context, the singular form of words used herein and in the appended claims includes the plural form, and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the terms “comprising” and “including” shall be interpreted as including rather than exclusively. Likewise, the terms “including” and “or” shall be interpreted as including unless such interpretation is expressly prohibited herein. Where the term “example” is used herein, particularly when it follows a set of terms, the “example” is merely exemplary and illustrative and should not be considered exclusive or extensive.

[0156] Further aspects and scope of adaptation become apparent from the description provided herein. It should be understood that various aspects of this application may be implemented individually or in combination with one or more other aspects. It should also be understood that the descriptions and specific embodiments herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0157] Several embodiments of this disclosure have been described in detail above. However, it is obvious that those skilled in the art can make various modifications and variations to the embodiments of this disclosure without departing from the spirit and scope of this disclosure. The scope of protection of this disclosure is defined by the appended claims.

Claims

1. A current modulation method for a CT scanning system, characterized in that, include: Acquire scanning data of the scanning phantom, and based on the scanning data, determine the major and minor axes of the scanning phantom cross-section at different scanning positions, as well as the average equivalent diameter of the scanning phantom; Based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at the same scanning positions is determined. Based on the relationship between scanning angle and scanning time and the first exposure current, the second exposure current of the X-ray tube at different scanning times at the same scanning position is determined. Based on the second exposure current, determine the rate of change of the X-ray tube current at different scanning times at the same scanning positions; Based on the relationship between the rate of change of X-ray tube current and the rate of change of preset dose of X-ray tube at different scanning times at the same scanning positions, the initial modulation coefficient of the first exposure current at each scanning position is adjusted to obtain the target modulation coefficient of the first exposure current of X-ray tube at each scanning position.

2. The method according to claim 1, characterized in that, The step of determining the major and minor axes of the scanned phantom cross-section at different scanning positions, and the average equivalent diameter of the scanned phantom, based on the scanned data, includes: Based on the scan data, the first scan data of the scanning phantom at different scan positions under the first scan angle is determined, and the second scan data of the scanning phantom at different scan positions under the second scan angle is determined, wherein the first scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is perpendicular to the scanning bed, and the second scan angle is the scan angle corresponding to when the X-ray of the X-ray tube is parallel to the scanning bed. Based on the first scan data of the scanned model at different scan positions under the first scan angle, the minor axis of the scanned model cross section at different scan positions is determined; Based on the second scanning data of the scanning model at different scanning positions under the second scanning angle, the major axis of the scanning model cross section at different scanning positions is determined; The average equivalent diameter of the scanned phantom is determined by the major and minor axes of the cross-section of the scanned phantom at different scanning positions.

3. The method according to claim 1, characterized in that, The step of determining the first exposure current of the X-ray tube at different scanning angles at the same scanning positions, based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, includes: Based on the major and minor axes of the scanned phantom cross section at different scanning positions, the path of X-rays passing through the scanned phantom cross section at different scanning angles at the same scanning positions is determined. Based on the path of X-rays through the cross section of the scanning phantom at different scanning angles at the same scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient, the first exposure current of the X-ray tube at different scanning angles at the same scanning positions is determined.

4. The method according to claim 3, characterized in that, The scanning angle at the z-scan position is... At that time, the path of the X-rays passing through the cross-section of the scanning phantom satisfies: in, This indicates the major axis of the scanned phantom section at the z-scan position. This indicates the minor axis of the scanned phantom section at the z-scan position. The scanning angle; The scanning angle at the z-scan position is... At that time, the first exposure current of the X-ray tube satisfies: in, As the reference current, The attenuation coefficient of the scanning phantom is... The average equivalent diameter of the scanning phantom. These are the initial modulation coefficients.

5. The method according to claim 1, characterized in that, The step of determining the rate of change of X-ray tube current at different scanning times at the same scanning position based on the second exposure current includes: Based on the second exposure current, the derivative of the second exposure current with respect to time is calculated to obtain the rate of change of the X-ray tube current at different scanning times at the same scanning positions.

6. The method according to claim 1, characterized in that, The step of adjusting the initial modulation coefficient of the first exposure current at each scanning position based on the relationship between the rate of change of the X-ray tube current and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position, includes: The actual dose change rate of the X-ray tube at different scanning times at different scanning positions is determined based on the rate of change of the X-ray tube current at different scanning times at different scanning positions. Based on the relationship between the actual dose change rate of the X-ray tube and the preset dose change rate at different scan times at the same scan position, when the actual dose change rate of the X-ray tube at the target scan position is greater than the preset dose change rate for at least one target scan time, the initial modulation coefficient of the first exposure current corresponding to the target scan time at the target scan position is adjusted to obtain the target modulation coefficient of the first exposure current of the X-ray tube at the target scan position.

7. The method according to claim 1, characterized in that, The method further includes: Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions Determine the scanning time interval corresponding to each scanning position; When the major axis difference information corresponding to two adjacent scanning positions is greater than the preset difference information, and / or the minor axis difference information is greater than the preset difference information, the scanning time interval corresponding to the two adjacent scanning positions is divided into three sub-scanning time intervals according to the scanning time interval corresponding to the two adjacent scanning positions, and the third sub-scanning time interval corresponding to the previous scanning position and the first sub-scanning time interval corresponding to the next scanning position are used as transition time intervals. Based on the pitch, collimator opening distance, frame rotation speed, and two adjacent scanning positions The major and minor axes of the scanning phantom sections corresponding to two adjacent scanning positions are used to determine the transition major and minor axes of the transition time interval.

8. The method according to claim 7, characterized in that, The major axis of the transition time interval satisfies: The minor axis of the transition time interval satisfies: in, This is the major axis of the cross-section of the scanning phantom corresponding to the next scanning position. This is the minor axis of the cross-section of the scanning phantom corresponding to the next scanning position. , , g represents the values ​​of two adjacent scan positions. , This is the collimator aperture distance. For pitch, The rotational speed of the frame, The minimum interval time for calculating the first exposure current within the CT scanning system is a fixed value.

9. A current modulation device for a CT scanning system, characterized in that, include: The data determination module is used to acquire the scanning data of the scanning model and, based on the scanning data, determine the major and minor axes of the cross-section of the scanning model at different scanning positions, as well as the average equivalent diameter of the scanning model. The first exposure current determination module is used to determine the first exposure current of the X-ray tube at different scanning angles at the same scanning positions based on the major and minor axes of the scanning phantom cross-section at different scanning positions, the average equivalent diameter of the scanning phantom, and the initial modulation coefficient. The second exposure current determination module is used to determine the second exposure current of the X-ray tube at different scanning times at the same scanning positions based on the correlation between the scanning angle and the scanning time and the first exposure current. The current change rate determination module is used to determine the current change rate of the X-ray tube at different scanning times at the same scanning positions based on the second exposure current. The correction module is used to adjust the initial modulation coefficient of the first exposure current at each scanning position based on the relationship between the rate of change of the X-ray tube current and the preset dose change rate of the X-ray tube at different scanning times at the same scanning position, so as to obtain the target modulation coefficient of the first exposure current of the X-ray tube at each scanning position.

10. A computer device, comprising: One or more processors; Storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors perform the method as described in any one of 1-8.

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