A phantom for testing dynamic imaging performance of CT equipment

Abstract

The present invention discloses a phantom for testing the dynamic imaging performance of a CT device, and relates to the technical field of medical imaging and radiotherapy. The present invention includes a phantom, which is composed of a fixed phantom, a moving phantom and a driving part, wherein the driving part drives the moving phantom to perform linear motion in the fixed phantom; the moving phantom is composed of a hollow tube, a target, a head, and a connecting plate; the driving part is a connecting rod mechanism, which is driven by a motor controller to control a motor, and the turntable and the connecting plate are connected by a connecting rod for rotation, and a plurality of holes are distributed along the radial direction on the turntable, and the connection between the connecting rod and the turntable is realized by inserting a first pin shaft into different holes, and the turning radius of the first pin shaft is quickly changed, thereby changing the motion range and crank length of the moving phantom, and realizing the change of the motion stroke of the moving phantom. The present invention has the advantages of simple structure, and the motion speed, motion stroke and motion curve can be arbitrarily set.

Description

Technical Field

[0001] The invention belongs to the technical field of medical imaging and radiotherapy, and in particular relates to a dynamic imaging performance test phantom for CT equipment. Background Art

[0002] At present, CT scanning technology is widely used in the entire process of radiotherapy due to its excellent structural imaging performance. With the development of high-efficiency radiotherapy technologies such as protons and heavy ions, the requirements for the delineation and positioning accuracy of tumor targets have been greatly improved. However, during the imaging process of CT equipment, motion artifacts caused by organ movement seriously affect the delineation and positioning accuracy of tumor targets. Gating and dynamic scanning technologies for moving organs have emerged, and a phantom is needed to test and verify the imaging performance of gating and dynamic scanning CT equipment. Summary of the invention

[0003] The present invention provides a CT equipment dynamic imaging performance test phantom, which solves the above problems.

[0004] To solve the above technical problems, the present invention is achieved through the following technical solutions:

[0005] A dynamic imaging performance test phantom of a CT device of the present invention comprises a phantom, which is composed of a fixed phantom, a moving phantom and a driving part. The driving part drives the moving phantom to perform linear motion in the fixed phantom.

[0006] Furthermore, the moving phantom is composed of a hollow tube, a target arranged in the hollow tube, and a connecting plate installed on the front end cover outside the hollow tube; the hollow tube corresponds to the circular hole opened on the side of the fixed phantom and cooperates with each other in telescopic motion forward and backward.

[0007] Furthermore, the driving part is a connecting rod mechanism, which is driven by a motor controlled by a motor controller. A turntable is installed at the center position of the driving shaft end of the motor. The turntable and the connecting plate are rotatably connected by a connecting rod. A plurality of holes are distributed along the radial direction on the turntable. The connection between the connecting rod and the turntable is achieved by inserting the first pin shaft into different holes, and the rotation radius of the first pin shaft is quickly changed, thereby changing the motion range of the moving mold and the crank length, thereby achieving a change in the motion stroke of the moving mold.

[0008] Furthermore, the motor controller adopts a programmable controller to control the motor to rotate according to a predetermined speed curve, thereby driving the motion model to move according to different speed curves.

[0009] Furthermore, the fixed mold body and the hollow tube are made of a low-density material that is conducive to the penetration of X-rays.

[0010] Furthermore, the target is made of medium-low density material;

[0011] Furthermore, during gated or dynamic imaging, the target in the hollow tube is positioned within the scanning plane of the CT device, the stroke and motion curve of the moving phantom are set, and then the moving phantom is started. After the corresponding scan is completed, the imaging accuracy of the CT device is evaluated by measuring the cross-sectional shape or motion stroke of the target in the tomographic image.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The phantom of the present invention can test and verify the imaging performance of gated and dynamic scanning CT equipment. During gated or dynamic imaging, the target of the phantom is positioned in the scanning plane, the stroke and motion curve of the phantom are set, and then the phantom is started. After the corresponding scan is completed, the imaging accuracy of the CT equipment is evaluated by measuring the cross-sectional shape or motion stroke of the target in the tomographic image. The phantom has the advantages of simple structure, and the motion speed, motion stroke and motion curve can be arbitrarily set. Of course, any product implementing the present invention does not necessarily need to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0015] Figure 1 This is a schematic diagram of the overall structure of a dynamic imaging performance test phantom for a CT device according to the present invention;

[0016] Figure 2 for Figure 1 Schematic diagram of the structure of the mid-motion motif;

[0017] Figure 3 for Figure 2 Transverse cross-section of

[0018] Figure 4 This is a schematic diagram of the structure of the test phantom of the present invention in a driving state;

[0019] Figure 5 for Figure 1 Schematic diagram of the structure of the middle turntable and the principle of stroke switching;

[0020] Figure 6 A schematic diagram of a state in which the test phantom of the present invention is combined with a CT device to work;

[0021] In the accompanying drawings, the list of components represented by each reference numeral is as follows: 100-fixed mold, 200-moving mold, 300-driving part; 201-connecting plate, 202-head, 203-hollow tube, 204-target; 301-motor controller, 302 first pin shaft, 303-motor, 304-motor bracket, 305-bearing bracket, 306-power supply, 307-turntable, 308-connecting rod, 309-driver, 310-second pin shaft. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0023] In the description of the present invention, it should be understood that terms such as "outer front end", "side", "center position", "radial direction" and the like indicating orientation or positional relationship are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] See also Figure 1-6 As shown, a dynamic imaging performance test phantom of a CT device of the present invention includes a phantom 10, which is composed of a fixed phantom 100, a moving phantom 200 and a driving part 300. The driving part 300 drives the moving phantom 200 to perform linear motion in the fixed phantom 100.

[0025] Among them, the moving phantom 200 is composed of a hollow tube 203, a target 204 arranged in the hollow tube 203, and a connecting plate 201 installed on the front end head 202 outside the hollow tube 203; the hollow tube 203 corresponds to the circular hole opened on the side of the fixed phantom 100 and is telescopically coordinated forward and backward to perform linear motion; in this specific embodiment, the target 204 is spherical, that is, a target ball, and the target 204 is made of medium-low density material, and polyformaldehyde is used in this specific embodiment; the fixed phantom 100 and the hollow tube 203 are made of a low-density material that is conducive to the passage of X-rays, and PMMA material is used in this specific embodiment.

[0026] Among them, the driving part 300 is a connecting rod mechanism, which is driven by the motor controller 301 controlling the motor 303. A turntable 307 is installed at the center position of the driving shaft end of the motor 303. The turntable 307 is rotatably connected to the connecting plate 201 through a connecting rod 308. There are multiple holes distributed along the radial direction on the turntable. In this specific embodiment, five holes are used. The connection between the connecting rod 308 and the turntable 307 is achieved by inserting the first pin shaft 302 into different holes, and the rotation radius of the first pin shaft 302 is quickly changed, thereby changing the motion range and crank length of the moving mold 200, thereby changing the motion stroke of the moving mold 200; the other end of the connecting rod 308 is connected to the connecting plate 201 through the second pin shaft 310 for fixation.

[0027] The rotating disk 307 and the shaft of the motor 303 are fixedly connected, the rotating disk 307 and the connecting rod 308 are rotationally connected via the pin shaft 302 , and the connecting rod 308 and the connecting plate 201 of the moving mold body 200 are rotationally connected via the second pin shaft 310 .

[0028] like Figure 5 As shown, the turntable 307 shows an embodiment of changing the crank length; the turntable 307 is designed with five mounting holes A, B, C, D, and E, and the first pin 302 can be inserted into these five holes; when the connecting rod 308 is connected to the turntable 307 through the first pin 302, the pin is inserted into different holes, and the corresponding crank length can be rotated, thereby changing the stroke of the moving mold 200. The above embodiment of changing the crank length is one of many embodiments, not all. All embodiments that can change the crank length are within the protection scope of this application.

[0029] Among them, the motor controller 301 adopts a programmable controller to control the motor 303 to rotate according to a predetermined speed curve, thereby driving the moving model 200 to move according to different speed curves; the motor 303 is installed on a supporting bracket 305, and a power supply 306 for power supply is installed in the supporting bracket 305. The motor 303 is fixedly installed on the supporting bracket 305 through a motor bracket 304; the lower part of the supporting bracket 305 is also fixedly installed with a driver connected to the power supply 306, and a motor controller 301 connected to the motor 303.

[0030] The driving part 300 can quickly change the stroke of the moving model by changing the position of the connecting rod on the turntable.

[0031] like Figure 6 As shown, during gated or dynamic imaging, the target 204 of the moving phantom 200 is positioned within the scanning plane of the CT device, the travel and motion curve of the moving phantom 200 are set, and then the moving phantom is started. After the corresponding scan is completed, the imaging accuracy of the CT device is evaluated by measuring the cross-sectional shape or motion travel of the target 204 in the tomographic image.

[0032] The quality of dynamic imaging (cross-section, coronal, and sagittal images) is determined by the similarity between the target contour in the image and the corresponding target actual cross-section contour. For example, the cross-section of a spherical target is theoretically circular. The closer the target contour of the reconstructed cross-section image is to a circle (high similarity), the better the reconstruction quality. The farther it is from a circle (low similarity), the worse the reconstruction quality.

[0033] The axial dynamic positioning accuracy of the CT scanning equipment is evaluated based on the deviation between the axial position of the target center in the dynamic image at different phases and the actual position of the target in the phantom. The smaller the deviation, the higher the dynamic positioning accuracy, and the larger the deviation, the worse the dynamic positioning accuracy.

[0034] Beneficial effects:

[0035] The phantom of the present invention can test and verify the imaging performance of gated and dynamic scanning CT equipment. During gated or dynamic imaging, the target of the phantom is positioned in the scanning plane, the stroke and motion curve of the phantom are set, and then the phantom is started. After the corresponding scan is completed, the imaging accuracy of the CT equipment is evaluated by measuring the cross-sectional shape or motion stroke of the target in the tomographic image. The phantom has the advantages of simple structure and arbitrary setting of the motion speed, motion stroke and motion curve.

[0036] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A phantom for testing dynamic imaging performance of a CT device, comprising a phantom (10), wherein the phantom (10) is composed of a fixed phantom (100), a moving phantom (200) and a driving part (300), wherein the driving part (300) drives the moving phantom (200) to perform linear motion in the fixed phantom (100), and wherein: The moving mold (200) is composed of a hollow tube (203), a target (204) disposed in the hollow tube (203), and a connecting plate (201) mounted on a front end cover (202) outside the hollow tube (203); the hollow tube (203) corresponds to a circular hole opened on the side of the fixed mold (100) and is telescopically matched forward and backward; The driving part (300) is a connecting rod mechanism, which is driven by a motor controller (301) to control a motor (303). A rotating disk (307) is installed at the center of the driving shaft end of the motor (303). The rotating disk (307) is rotatably connected to the connecting plate (201) via a connecting rod (308). A plurality of holes are distributed along the radial direction on the rotating disk. The first pin shaft (302) is inserted into different holes to achieve connection between the connecting rod (308) and the rotating disk (307), so that the first pin shaft (302) can be quickly changed. The turning radius of the movable mold (302) is changed, thereby changing the moving range and crank length of the movable mold (200), thereby changing the moving stroke of the movable mold (200); the turntable (307) is designed with five mounting holes A, B, C, D, and E, and the first pin shaft (302) can be inserted into these five holes; when the connecting rod (308) is connected to the turntable (307) through the first pin shaft (302), the pin shaft is inserted into different holes, and the corresponding crank length can be rotated, thereby changing the stroke of the movable mold (200); During gated or dynamic imaging, the target (204) of the moving phantom (200) is positioned within the scanning plane of the CT device, the travel and motion curve of the moving phantom (200) are set, and then the moving phantom is started. After the corresponding scan is completed, the imaging accuracy of the CT device is evaluated by measuring the cross-sectional shape or motion travel of the target (204) in the tomographic image; The dynamic imaging quality is confirmed based on the similarity between the target contour in the image and the corresponding actual cross-sectional contour of the target; the higher the similarity, the better the reconstruction quality, and the lower the similarity, the worse the reconstruction quality; the axial dynamic positioning accuracy of the CT scanning equipment is evaluated based on the deviation between the axial position of the target center in the dynamic image at different phases and the actual position of the target in the phantom. The smaller the deviation, the higher the dynamic positioning accuracy, and the larger the deviation, the worse the dynamic positioning accuracy; The motor controller (301) is a programmable controller, which controls the motor (303) to rotate according to a predetermined speed curve, thereby driving the motion model (200) to move according to different speed curves; The fixed mold body (100) and the hollow tube (203) are made of a low-density material that is conducive to the penetration of X-rays; the low-density material is specifically PMMA material; The target (204) is made of a medium-low density material, and the medium-low density material is specifically polyoxymethylene.

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