Method and system for adjusting the z-direction position of a rotating detector module based on a steel ball phantom

Abstract

The present invention discloses a method and system for adjusting the z-direction position of a rotating detector module based on a steel ball phantom, comprising: a scanning base, a transfer mechanism, a ray tube, a ray detector and a steel ball phantom; the scanning base can be driven to rotate and be equipped with a transfer mechanism, one side of the transfer mechanism is fixedly equipped with a ray tube capable of emitting X-rays, and the transfer mechanism is fixedly equipped with a ray detector capable of receiving X-rays on the opposite side of the ray tube; the steel ball phantom is positioned on the scanning base, and the steel ball phantom corresponds to the ray transmission path between the ray tube and the ray detector. The method solves the technical problem that when the static exposure calculation adjustment is used for the detector module position in the prior art, there is a difference between the calculation adjustment result of the actual rotation exposure of the transfer mechanism, and the adjustment effect is not good.

Description

Technical Field

[0001] The present invention relates to the technical field of CT system module calibration, and in particular to a method and system for adjusting the position of a rotating detector module in the z direction based on a steel ball phantom. Background Art

[0002] At present, in CT systems, in order to ensure a clearer image, when installing the detector modules, it is required that the positions of all detector modules in the z direction be as consistent as possible, that is, the z direction position difference of each detector module is required to be very small. Therefore, after the detector modules are installed, it is usually necessary to calculate the position of the module in the z direction, and then adjust the z direction position according to the calculation results to meet the production requirements.

[0003] In the prior art, static exposure is generally used for calculation of module position, that is, slits are used to image the detector module through collimating blades, and then adjustments are made based on the collected module data. However, since this method is performed in a static state, the CT system is actually used for rotational exposure through a transfer mechanism. In other words, due to the dynamic influence of the rotational exposure of the transfer mechanism, the result of the static exposure calculation adjustment may be inconsistent with that during rotation, resulting in poor static adjustment of the module position. Summary of the invention

[0004] To this end, the present invention provides a method and system for adjusting the z-direction position of a rotating detector module based on a steel ball phantom, so as to solve the problem in the prior art that when static exposure calculation adjustment is used for the position of the detector module, there is a difference between the calculated adjustment result of the actual rotation exposure of the transfer mechanism, resulting in poor adjustment effect.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for adjusting the position of a rotating detector module in the z direction based on a steel ball phantom comprises the following steps:

[0007] The steel ball phantom is placed in place based on a specific scanning position of the scanning base, and the indexing mechanism located on the scanning base is started to rotate and scan to acquire the steel ball group data;

[0008] Exit the steel ball phantom, and use the same scanning conditions as those for scanning the steel ball phantom to scan and obtain the air group data;

[0009] Pre-process the steel ball group data and the air group data, and compare them to obtain the steel ball attenuation data;

[0010] Select the view data of the steel ball projected on the center of the detector module in the x direction, calculate the position of the steel ball corresponding to the detector module, and finally calculate the steel ball positions corresponding to several groups of detector modules;

[0011] Perform polynomial fitting operation according to the index values ​​of several groups of detector modules and their corresponding steel ball positions, and subtract the fitted positions from the actual positions of several groups of detector modules to obtain the position differences of several groups of detector modules;

[0012] According to the position difference values ​​of the plurality of groups of detector modules, the position of each group of detector modules corresponding to the z direction is adjusted respectively until the difference values ​​of each group are within the required threshold range.

[0013] On the basis of the above technical solution, the present invention is further described as follows:

[0014] As a further solution of the present invention, placing the steel ball phantom in place based on a specific scanning position of the scanning base, and starting the indexing mechanism located on the scanning base to rotate and scan and collect the steel ball group data specifically include:

[0015] The steel ball phantom is suspended in the air on a positioning mechanism, and based on the positioning mechanism, the steel ball phantom is assembled to the predetermined exposure scanning position of the scanning base and kept positioned and stationary. Then, the transfer mechanism located on the scanning base is controlled to perform rotational exposure scanning on the steel ball phantom that remains positioned and stationary according to the set driving parameters, thereby collecting the rotational exposure scanning data of the steel ball phantom, that is, the steel ball group data.

[0016] As a further solution of the present invention, the step of exiting the steel ball phantom and scanning the air group data using the same scanning conditions as those for scanning the steel ball phantom specifically includes:

[0017] The steel ball phantom is exited, and the indexing mechanism located on the scanning base is continuously controlled to perform exposure rotation tomography on the air according to the driving parameters set for exposing the steel ball phantom in the above process, so as to obtain the air group data.

[0018] As a further solution of the present invention, the view data of the steel ball projected on the center of the detector module in the x direction is selected to calculate the position of the steel ball corresponding to the detector module, and finally calculate the steel ball positions corresponding to several groups of detector modules, specifically including:

[0019] Select the view data corresponding to the steel ball attenuation data projected on the center of the detector module in the x direction, and then calculate the z direction position of the steel ball in the view data. The z direction position of the steel ball is the centroid of the steel ball attenuation data curve in the z direction of the detector module. The conversion formula is as follows:

[0020]

[0021] Wherein, P represents the position of the steel ball in the z direction of the detector module, D represents the attenuation data value of the steel ball, and S is the slice index value corresponding to the detector module;

[0022] Finally, the positions of the steel balls corresponding to several groups of detector modules in the z direction are calculated.

[0023] As a further solution of the present invention, the polynomial fitting operation is performed according to the index values ​​of the plurality of detector modules and their corresponding steel ball positions, and the position differences of the plurality of detector modules are obtained by subtracting the fitted positions from the actual positions of the plurality of detector modules, which specifically includes:

[0024] After calculating the steel ball positions corresponding to each group of detector modules in the z direction, a polynomial fitting operation is performed based on the index values ​​of several groups of detector modules and their corresponding steel ball positions to obtain smooth fitting position curves of several groups of detector modules, and further a difference operation is performed between the smooth fitting position curves and the actual positions of several groups of detector modules to obtain the position differences of several groups of detector modules.

[0025] As a further solution of the present invention, the position of each group of detector modules corresponding to the z direction is adjusted according to the position difference values ​​of the plurality of groups of detector modules, until the difference values ​​of each group are within the required threshold range, specifically including:

[0026] According to the position difference values ​​of several groups of detector modules, the positions of the detector modules whose difference values ​​exceed the threshold range are adjusted along the z direction until the position difference values ​​of several groups of detector modules are all within the threshold range, that is, the position adjustment of several groups of detector modules in the z direction is completed.

[0027] A system for executing the method for adjusting the position of a rotating detector module in the z direction based on a steel ball phantom, the system comprising:

[0028] Scanning base, indexing mechanism, X-ray tube, X-ray detector and steel ball phantom;

[0029] The scanning base can be driven to rotate and be equipped with a transfer mechanism, one side of the transfer mechanism is fixedly equipped with the radiation tube capable of emitting X-rays, and the opposite side of the transfer mechanism corresponding to the radiation tube is fixedly equipped with the radiation detector capable of receiving X-rays, when the scanning base controls the rotation of the transfer mechanism, the rotation of the transfer mechanism drives the radiation tube and the radiation detector to rotate synchronously for exposure scanning;

[0030] The steel ball phantom is positioned on the scanning base, and the steel ball phantom corresponds to the ray transmission path between the ray tube and the ray detector. When the ray tube rotates based on the indexing mechanism, X-rays are synchronously and continuously emitted. After passing through the steel ball phantom, the X-rays form attenuated rays that are emitted to the ray detector. The ray detector continuously receives the attenuated rays formed by passing through the steel ball phantom at a specific frequency, and stores the continuously received attenuated ray data in a specific format.

[0031] As a further solution of the present invention, the steel ball phantom is suspended on a positioning mechanism, the positioning mechanism is configured as a scanning bed mechanism, and the steel ball phantom is located in a radiation transmission path between the radiation tube and the radiation detector based on the scanning bed mechanism.

[0032] As a further solution of the present invention, the steel ball mold body is configured as a mold body base extending in a direction and steel balls movably arranged on the mold body base, and the mold body base is arranged along the z direction as a whole, and the z direction is the rotation axis of the transfer mechanism.

[0033] As a further solution of the present invention, it also includes: a detector module;

[0034] The detector modules are provided in a plurality of groups, and the plurality of groups of the detector modules are respectively arranged along the x-direction and located at positions of the transfer mechanism corresponding to the radiation detectors;

[0035] The x-direction is a direction that is synchronously perpendicular to the z-direction and the radial direction of the circle corresponding to the indexing mechanism.

[0036] The present invention has the following beneficial effects:

[0037] The system and method use a steel ball as a phantom, and utilize a transfer mechanism to perform rotational exposure scanning on the steel ball phantom to collect data, thereby calculating the z-direction position of the detector module and making targeted position adjustments to the detector module, thereby achieving greater consistency with actual usage scenarios and achieving higher image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the implementation mode of the present invention or the technical solution in the prior art, the drawings required for the implementation mode or the description of the prior art will be briefly introduced below. The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0039] Figure 1Schematic diagram of the overall structure of the z-direction positioning system of the rotary detector module based on the steel ball phantom provided in an embodiment of the present invention.

[0040] Figure 2 A schematic diagram of the arrangement of detector modules in a z-direction positioning system of a rotating detector module based on a steel ball phantom provided in an embodiment of the present invention.

[0041] Figure 3 A schematic diagram of the overall process of a method for adjusting the z-direction position of a rotary detector module based on a steel ball phantom provided in an embodiment of the present invention.

[0042] Figure 4 A schematic diagram of the position difference value of the detector module in the z-direction adjustment method of the rotating detector module based on the steel ball phantom provided in an embodiment of the present invention.

[0043] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0044] Scanning base 1; transfer mechanism 2; X-ray tube 3; X-ray detector 4; scanning hole 5; steel ball phantom 6; detector module 7. DETAILED DESCRIPTION

[0045] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The terms such as "upper", "lower", "left", "right", and "middle" used in this specification are only for the convenience of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships should be regarded as within the scope of the invention without substantially changing the technical content.

[0047] like Figure 1 to Figure 2 As shown, the embodiment of the present invention provides a rotating detector module z-direction adjustment system based on a steel ball phantom, including a scanning base 1, a transfer mechanism 2, a X-ray tube 3, a X-ray detector 4, a scanning hole 5, a steel ball phantom 6 and a detector module 7, which is used to collect data by using the steel ball phantom 6 and performing a rotation exposure scan of the steel ball phantom 6 using the transfer mechanism 2, thereby calculating the z-direction position of the detector module 7, and making targeted position adjustments to the detector module 7, thereby achieving a more consistent with the actual use scenario, thereby achieving higher image quality. The specific settings are as follows:

[0048] Please refer to Figure 1and Figure 2 The scanning base 1 can be driven to rotate and is equipped with a transfer mechanism 2. A ray tube 3 capable of emitting X-rays is fixedly installed on one side of the transfer mechanism 2, and a ray detector 4 capable of receiving X-rays is fixedly installed on the opposite side of the transfer mechanism 2 corresponding to the ray tube 3. When the scanning base 1 controls the transfer mechanism 2 to rotate, the rotation of the transfer mechanism 2 can drive the ray tube 3 and the ray detector 4 to rotate synchronously for exposure scanning.

[0049] The steel ball phantom 6 is suspended on a positioning mechanism, and the positioning mechanism is configured as a scanning bed mechanism. The steel ball phantom 6 is synchronously arranged at the scanning hole 5 of the scanning base 1 based on the scanning bed mechanism, and the steel ball phantom 6 corresponds to the ray transmission path between the ray tube 3 and the ray detector 4, so as to realize that when the ray tube 3 rotates based on the indexing mechanism 2, the X-ray can be synchronously and continuously emitted. After passing through the steel ball phantom 6, the X-ray forms an attenuated ray which is further emitted to the ray detector 4. The ray detector 4 can continuously receive the attenuated ray formed by passing through the steel ball phantom 6 at a specific frequency, and store the continuously received attenuated ray data in a specific format.

[0050] For details, please refer to Figure 1 and Figure 2 The steel ball mold body 6 is configured as a mold body base extending in a direction and steel balls movably arranged on the mold body base, and the mold body base is arranged along the z direction as a whole.

[0051] Please continue to refer to Figure 1 and Figure 2 The detector modules 7 are provided in a plurality of groups, and the plurality of groups of the detector modules 7 are respectively arranged along the x-direction and located at positions of the transfer mechanism 2 corresponding to the radiation detectors 4 .

[0052] Please refer to Figure 3 and Figure 4 The embodiment of the present invention also provides a method for adjusting the position of a rotating detector module in the z direction based on a steel ball phantom, which specifically includes the following steps:

[0053] S1: placing the steel ball phantom 6 in place based on a specific scanning position of the scanning base 1, and starting the indexing mechanism 2 located on the scanning base 1 to rotate and scan and collect the steel ball group data;

[0054] The specific process is as follows: the steel ball phantom 6 is suspended on a positioning mechanism, and based on the positioning mechanism, the steel ball phantom 6 is assembled to the exposure scanning predetermined position of the scanning base 1 and kept positioned and stationary, and then the indexing mechanism 2 located on the scanning base 1 is controlled to perform rotational exposure scanning on the steel ball phantom 6 that is kept positioned and stationary according to the set driving parameters, thereby acquiring the rotational exposure scanning data of the steel ball phantom 6, that is, the steel ball group data;

[0055] S2: exit the steel ball phantom 6, and scan the air group data using the same scanning conditions as those for scanning the steel ball phantom 6;

[0056] The specific process is: exit the steel ball phantom 6, continue to control the indexing mechanism 2 located on the scanning base 1 to perform exposure rotation tomography on the air according to the driving parameters set in the above process for exposing the steel ball phantom 6, and obtain the air group data;

[0057] S3: pre-process the steel ball group data and the air group data, and compare them to obtain the steel ball attenuation data;

[0058] S4: Select the view data of the steel ball projected on the center of the detector module 7 in the x direction, calculate the position of the steel ball corresponding to the detector module 7, and finally calculate the positions of the steel balls corresponding to several groups of detector modules 7;

[0059] The specific process is: select the view data corresponding to the steel ball attenuation data projected on the x-direction center of the detector module 7, and then calculate the z-direction position of the steel ball in the view data. The z-direction position of the steel ball is the centroid of the steel ball attenuation data curve in the z-direction distribution of the detector module 7. The conversion formula is as follows:

[0060]

[0061] Wherein, P represents the position of the steel ball in the z direction of the detector module 7, D represents the attenuation data value of the steel ball, and S is the slice index value corresponding to the detector module 7;

[0062] Finally, the positions of the steel balls corresponding to the several groups of detector modules 7 in the z direction are calculated;

[0063] S5: performing a polynomial fitting operation according to the index values ​​of the plurality of detector modules 7 and their corresponding steel ball positions, and subtracting the fitted positions from the actual positions of the plurality of detector modules 7 to obtain position differences of the plurality of detector modules 7;

[0064] The specific process is as follows: after calculating the steel ball positions corresponding to each group of detector modules 7 in the z direction, a polynomial fitting operation is performed according to the index values ​​of the plurality of detector modules 7 and their corresponding steel ball positions to obtain the smooth fitting position curves of the plurality of detector modules 7, and further a difference operation is performed between the smooth fitting position curves and the actual positions of the plurality of detector modules 7 to obtain the position differences of the plurality of detector modules 7;

[0065] S6: According to the position difference values ​​of the plurality of groups of detector modules 7, the position of each group of detector modules 7 corresponding to the z direction is adjusted respectively until the difference values ​​of each group are within the required threshold range;

[0066] The specific process is: according to the position difference values ​​of several groups of detector modules 7, the positions of the detector modules 7 whose difference values ​​exceed the threshold range are adjusted along the z direction until the position difference values ​​of several groups of detector modules 7 are all within the threshold range, that is, the position adjustment of several groups of detector modules 7 in the z direction is completed.

[0067] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for adjusting the position of a rotating detector module in the z direction based on a steel ball phantom, characterized in that: The steps include: The steel ball phantom is placed in place based on a specific scanning position of the scanning base, and the indexing mechanism located on the scanning base is started to rotate and scan to acquire the steel ball group data; Exit the steel ball phantom, and use the same scanning conditions as those for scanning the steel ball phantom to scan and obtain the air group data; Pre-process the steel ball group data and the air group data, and compare them to obtain the steel ball attenuation data; Select the view data of the steel ball projected on the center of the detector module in the x direction, calculate the position of the steel ball corresponding to the detector module, and finally calculate the steel ball positions corresponding to several groups of detector modules; Perform polynomial fitting operation according to the index values ​​of several groups of detector modules and their corresponding steel ball positions, and subtract the fitted positions from the actual positions of several groups of detector modules to obtain the position differences of several groups of detector modules; According to the position difference values ​​of the plurality of groups of detector modules, respectively adjusting the position of each group of detector modules corresponding to the z direction until the difference values ​​of each group are within the required threshold range; The steel ball phantom is placed in place based on a specific scanning position of the scanning base, and a rotation scanning mechanism located on the scanning base is started to collect the steel ball group data, specifically including: The steel ball phantom is suspended in the air on a positioning mechanism, and based on the positioning mechanism, the steel ball phantom is assembled to the predetermined exposure scanning position of the scanning base and kept positioned and stationary. Then, the transfer mechanism located on the scanning base is controlled to perform rotational exposure scanning on the steel ball phantom that remains positioned and stationary according to the set driving parameters, thereby collecting the rotational exposure scanning data of the steel ball phantom, that is, the steel ball group data.

2. The method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 1, characterized in that: The step of exiting the steel ball phantom and scanning the air group data using the same scanning conditions as those for scanning the steel ball phantom specifically includes: The steel ball phantom is exited, and the indexing mechanism located on the scanning base is continuously controlled to perform exposure rotation tomography on the air according to the driving parameters set for exposing the steel ball phantom in the above process, so as to obtain the air group data.

3. The method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 2, characterized in that: The selecting of the view data of the steel ball projected on the center of the detector module in the x direction, calculating the position of the steel ball corresponding to the detector module, and finally calculating the positions of the steel balls corresponding to several groups of detector modules, specifically includes: Select the view data corresponding to the projection of the steel ball attenuation data on the center of the detector module in the x direction, and then calculate the z direction position of the steel ball in the view data. The z direction position of the steel ball is the centroid of the steel ball attenuation data curve in the z direction of the detector module. The conversion formula is as follows: in, P Indicates the position of the steel ball in the z direction of the detector module. D Indicates the steel ball attenuation data value, s It is the slice index value corresponding to the detector module; Finally, the positions of the steel balls corresponding to several groups of detector modules in the z direction are calculated.

4. The method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 3 is characterized in that: The polynomial fitting operation is performed according to the index values ​​of the plurality of detector modules and the steel ball positions corresponding thereto, and the position differences of the plurality of detector modules are obtained by subtracting the fitted positions from the actual positions of the plurality of detector modules, specifically including: After calculating the steel ball positions corresponding to each group of detector modules in the z direction, a polynomial fitting operation is performed based on the index values ​​of several groups of detector modules and their corresponding steel ball positions to obtain smooth fitting position curves of several groups of detector modules, and further a difference operation is performed between the smooth fitting position curves and the actual positions of several groups of detector modules to obtain the position differences of several groups of detector modules.

5. The method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 4, characterized in that: The method of adjusting the position of each group of detector modules corresponding to the z direction according to the position difference values ​​of the plurality of groups of detector modules respectively until the difference values ​​of each group are within the required threshold range specifically includes: According to the position difference values ​​of several groups of detector modules, the positions of the detector modules whose difference values ​​exceed the threshold range are adjusted along the z direction until the position difference values ​​of several groups of detector modules are all within the threshold range, that is, the position adjustment of several groups of detector modules in the z direction is completed.

6. A system for executing the method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom as claimed in claim 5, characterized in that: The system comprises: Scanning base, indexing mechanism, X-ray tube, X-ray detector and steel ball phantom; The scanning base can be driven to rotate and be equipped with a transfer mechanism, one side of the transfer mechanism is fixedly equipped with the radiation tube capable of emitting X-rays, and the opposite side of the transfer mechanism corresponding to the radiation tube is fixedly equipped with the radiation detector capable of receiving X-rays, when the scanning base controls the rotation of the transfer mechanism, the rotation of the transfer mechanism drives the radiation tube and the radiation detector to rotate synchronously for exposure scanning; The steel ball phantom is positioned on the scanning base, and the steel ball phantom corresponds to the ray transmission path between the ray tube and the ray detector. When the ray tube rotates based on the indexing mechanism, X-rays are synchronously and continuously emitted. After passing through the steel ball phantom, the X-rays form attenuated rays that are emitted to the ray detector. The ray detector continuously receives the attenuated rays formed by passing through the steel ball phantom at a specific frequency, and stores the continuously received attenuated ray data in a specific format.

7. The system for executing the method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 6, characterized in that: The steel ball phantom is suspended on a positioning mechanism, and the positioning mechanism is configured as a scanning bed mechanism. The steel ball phantom is located on a ray transmission path between the ray tube and the ray detector based on the scanning bed mechanism.

8. The system for executing the method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 7, characterized in that: The steel ball mold body is configured as a mold body base extending in a direction and a steel ball movably arranged on the mold body base. The mold body base is arranged along the z direction as a whole, and the z direction is the rotation axis of the indexing mechanism.

9. The system for executing the method for adjusting the z-direction position of a rotating detector module based on a steel ball phantom according to claim 8, characterized in that: Also includes: Detector module; The detector modules are provided in a plurality of groups, and the plurality of groups of the detector modules are respectively arranged along the x-direction and located at positions of the transfer mechanism corresponding to the radiation detectors; The x-direction is a direction that is synchronously perpendicular to the z-direction and the radial direction of the circle corresponding to the indexing mechanism.

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