Cranial motion artifact phantom and method for computed tomography technology

Abstract

The invention relates to a cranial motion artifact phantom and method for a computed tomography technology, and belongs to the field of quality control of medical imaging systems. The phantom comprises an upper die body, a moving part, a guide rail, a piezoelectric driving device and a base, the upper die body is arranged above the moving part through the groove; the moving part is connected to the upper surface of the guide rail through a screw; the guide rail is connected to the upper surface of the base through screws. And the piezoelectric driving device is connected to the upper surface of the base through a screw. The driving method comprises the steps that when continuous zigzag voltage is applied to the piezoelectric stack, based on the stick-slip driving principle, the guide rail conducts linear stepping type movement, the moving part moves along with the guide rail, and therefore the upper die body is driven to achieve three-axis movement. The device has the advantages that the size is small, multi-axis movement can be achieved through a single-layer structure, cranial movement artifacts generated in the computed tomography examination process can be simulated, and the device has good application prospects in the field of medical imaging systems.

Description

Technical Field

[0001] The present invention relates to the field of quality control of medical imaging systems, and particularly to a cranial motion artifact phantom and method for computed tomography technology, which can simulate the cranial motion artifacts generated by involuntary movements of patients during computed tomography examinations. It has the characteristics of small size and multi-axis movement with single-layer drive, and can be used in fields such as biomedical engineering and medical imaging. Background Art

[0002] A phantom in medicine refers to a physical model used to simulate the characteristics of human tissues or organs, and it has extensive applications in medical device calibration, clinical optimization of radiotherapy plans, and testing the performance of imaging technologies. However, the functions of existing phantoms are limited to imaging quality detection and control of medical imaging devices, such as testing and calibrating magnetic resonance imaging and other devices, and there is a lack of phantoms that can truly simulate the human state under physiological or pathological conditions. In addition, existing phantoms can be divided into static phantoms and dynamic phantoms. Among them, dynamic phantoms add a dynamic movement function on the basis of realizing the imaging quality detection and control function to achieve dynamic adjustment and conversion of measurement parameters, but they cannot simulate the tissue morphology and changes when the human body is in a moving state, such as the physiological state during breathing movement and involuntary movement of patients, thus directly reducing the application range and the accuracy and authenticity of the results of existing phantoms. At the same time, during contrast imaging of patients, motion artifacts often appear in the imaging results due to normal physiological movements or involuntary movements. The existence of motion artifacts will affect the quality of the imaging and directly interfere with the accuracy of doctors' diagnoses. Therefore, it is crucial to find methods to reduce motion artifacts. However, existing methods for eliminating motion artifacts require direct testing by patients during the process of testing feasibility, which will cause additional radiation damage to patients. Therefore, it is crucial to develop a phantom that can simulate motion artifacts generated by involuntary movements of patients. Summary of the Invention

[0003] The purpose of the present invention is to provide a cranial motion artifact phantom and method for computed tomography technology to solve the above problems existing in the prior art.

[0004] The technical solutions adopted by the present invention to achieve the above purpose are as follows.

[0005] A cranial motion artifact phantom for computed tomography technology, characterized in that it comprises an upper phantom (1), a motion component (2), guide rails (3-1), guide rails (3-2), a piezoelectric driving device (4), and a base (5); the motion component (2) comprises a two-degree-of-freedom motion component (2-1) and a single-degree-of-freedom motion component (2-2); the piezoelectric driving device (4) comprises a displacement amplification hinge (4-1), a piezoelectric stack (4-2), a piezoelectric stack (4-3), an X-axis driving foot (4-4), and a Y-axis driving foot (4-5); the upper phantom (1) is placed above the motion component (2) through a groove; the motion component (2) is connected to the upper surfaces of the guide rails (3-1) and the guide rails (3-2) by screws; the guide rails (3-1) and the guide rails (3-2) are connected to the upper surface of the base (5) by screws; the piezoelectric driving device (4) is connected to the upper surface of the base (5) by screws; the two-degree-of-freedom motion component (2-1) is connected to the upper surface of the guide rail (3-1) by screws; the single-degree-of-freedom motion component (2-2) is connected to the upper surfaces of the guide rail (3-2) and the guide rail (3-3) by screws; the two-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2) are mutually engaged through grooves; the displacement amplification hinge (4-1) is connected to the upper surface of the base (5) by screws and is pre-tightened and installed at the corresponding position of the base (5); the piezoelectric stacks (4-2) and the piezoelectric stack (4-3) are pre-tightened and installed in the grooves of the displacement amplification hinge (4-1).

[0006] The present invention provides a driving method capable of realizing a cranial motion artifact phantom for computed tomography technology, comprising the following steps.

[0007] (a) Due to the existence of the pre-tightening force, a static friction force is generated between the X-axis driving foot (4-4) and the guide rail (3-1), and its direction is perpendicular to the plane of the guide rail (3-1) and points to the outside of the guide rail (3-1). A static friction force is generated between the Y-axis driving foot (4-5) and the guide rail (3-2), and its direction is perpendicular to the plane of the guide rail (3-2) and points to the outside of the guide rail (3-2). A continuous sawtooth driving voltage is applied to the piezoelectric stack (4-2) and the piezoelectric stack (4-3). When the voltage rises slowly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) slowly elongate, causing the flexible part in the displacement amplification mechanism (4-1) to undergo elastic deformation. As the degree of elastic deformation gradually increases, the component of the friction force generated between the X-axis driving foot (4-4) and the guide rail (3-1) in the plane parallel to the guide rail (3-1) gradually increases, and the component of the friction force generated between the Y-axis driving foot (4-5) and the guide rail (3-2) in the plane parallel to the guide rail (3-2) gradually increases. When the magnitude of the component of the friction force exceeds the maximum static friction force between the guide rail (3-1), the guide rail (3-2) and the X-axis driving foot (4-4) and the Y-axis driving foot (4-5), the guide rail (3-1) and the guide rail (3-2) slide along the direction of the component of the friction force, and the guide rail (3-3) also moves accordingly. When the driving voltage drops rapidly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) quickly shorten, and the displacement amplification hinge (4-1) quickly returns to the initial state. During this process, the guide rail (3-1), the guide rail (3-2), and the guide rail (3-3) remain relatively stationary, and the piezoelectric driving device (4) returns to the initial state. Repeating this process can achieve the continuous linear stepping motion of the guide rail (3-1), the guide rail (3-2), and the guide rail (3-3). Further, the guide rail (3-1) drives the two-degree-of-freedom moving part (2-1) to move in the X direction, and the guide rail (3-2) and the guide rail (3-3) drive the one-degree-of-freedom moving part (2-2) to move in the Y direction, realizing the continuous stepping motion of the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2). Furthermore, the upper die body (1) connected to the two through the grooves is driven by the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) to move on the X-axis and the Y-axis. Further, since the contact surfaces between the upper die body (1) and the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) are slopes, when the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) approach each other, they can drive the upper die body (1) to move vertically upward, and then the upper die body (1) moves linearly along the Z-axis. In summary, the X, Y, and Z-axis movements of the upper die body can be achieved. The involuntary movement of the patient's head during a computed tomography scan can be decomposed into component movements in the X, Y, and Z directions. Therefore, the movement of the upper die body can fully simulate the involuntary movement of the patient's head. (b) By adjusting the driving voltage amplitude and frequency of the piezoelectric stacks (4-2) and (4-3), the regulation of their movement speed can be achieved; (c) By applying a reverse sawtooth driving voltage to the piezoelectric stacks (4-2) and (4-3), reverse movement can be achieved.

[0008] The advantages of the present invention are as follows: The structure is simple, easy to process and assemble, can simulate the cranial motion artifacts generated by the involuntary movement of patients, and has good application prospects in the research of eliminating motion artifacts and in the field of quality control of medical imaging systems. Description of the Drawings

[0009] The drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic examples and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0010] Figure 1 It is an exploded perspective view of the overall structure of the present invention;

[0011] Figure 2 It is a top view of the displacement amplification hinge of the present invention;

[0012] Figure 3 It is a schematic perspective view of the upper mold body of the present invention;

[0013] Figure 4 It is a timing diagram of the driving voltage of the present invention;

[0014] In the figure: 1, upper mold body; 2, moving part; 2-1, double-degree-of-freedom moving part; 2-2, single-degree-of-freedom moving part; 3, guide rail; 4, piezoelectric driving device; 4-1, displacement amplification hinge; 4-2, piezoelectric stack; 4-3, piezoelectric stack; 4-4, X-axis driving foot; 4-5, Y-axis driving foot; 5, base. Specific Implementation Method

[0015] The following further describes the detailed content and specific implementation manner of the present invention in conjunction with the drawings.

[0016] See Figure 1As shown in the figure, the cranial motion artifact phantom for computer tomography technology of the present invention is characterized in that it includes an upper mold body (1), a moving part (2), guide rails (3-1), guide rails (3-2), a piezoelectric driving device (4), and a base (5); the moving part (2) includes a two-degree-of-freedom moving part (2-1) and a single-degree-of-freedom moving part (2-2); the piezoelectric driving device (4) includes a displacement amplification hinge (4-1), a piezoelectric stack (4-2), a piezoelectric stack (4-3), an X-axis driving foot (4-4), and a Y-axis driving foot (4-5); the upper mold body (1) is placed above the moving part (2) through a groove; the moving part (2) is connected to the upper surfaces of the guide rails (3-1) and guide rails (3-2) by screws; the guide rails (3-1) and guide rails (3-2) are connected to the upper surface of the base (5) by screws; the piezoelectric driving device (4) is connected to the upper surface of the base (5) by screws; the two-degree-of-freedom moving part (2-1) is connected to the upper surface of the guide rail (3-1) by screws; the single-degree-of-freedom moving part (2-2) is connected to the upper surfaces of the guide rail (3-2) and guide rail (3-3) by screws; the two-degree-of-freedom moving part (2-1) and the single-degree-of-freedom moving part (2-2) are mutually engaged through a groove; the displacement amplification hinge (4-1) is connected to the upper surface of the base (5) by screws and is pre-tightened and installed at the corresponding position on the base (5); the piezoelectric stacks (4-2) and piezoelectric stack (4-3) are pre-tightened and installed in the groove of the displacement amplification hinge (4-1).

[0017] See Figures 1 to 4 As shown in the figure, specifically describe the driving method of the cranial motion artifact phantom for computer tomography technology, including.

[0018] (a) Due to the existence of the pre-tightening force, a static friction force is generated between the X-axis driving foot (4-4) and the guide rail (3-1), and its direction is perpendicular to the plane of the guide rail (3-1) and points to the outside of the guide rail (3-1). A static friction force is generated between the Y-axis driving foot (4-5) and the guide rail (3-2), and its direction is perpendicular to the plane of the guide rail (3-2) and points to the outside of the guide rail (3-2). A continuous sawtooth driving voltage is applied to the piezoelectric stack (4-2) and the piezoelectric stack (4-3). When the voltage rises slowly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) slowly elongate, causing the flexible part in the displacement amplification mechanism (4-1) to undergo elastic deformation. As the degree of elastic deformation gradually increases, the component of the friction force generated between the X-axis driving foot (4-4) and the guide rail (3-1) in the plane parallel to the guide rail (3-1) gradually increases, and the component of the friction force generated between the Y-axis driving foot (4-5) and the guide rail (3-2) in the plane parallel to the guide rail (3-2) gradually increases. When the magnitude of the component of the friction force exceeds the maximum static friction force between the guide rail (3-1), the guide rail (3-2) and the X-axis driving foot (4-4) and the Y-axis driving foot (4-5), the guide rail (3-1) and the guide rail (3-2) slide along the direction of the component of the friction force, and the guide rail (3-3) also moves accordingly. When the driving voltage drops rapidly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) quickly shorten, and the displacement amplification hinge (4-1) quickly returns to the initial state. During this process, the guide rail (3-1), the guide rail (3-2), and the guide rail (3-3) remain relatively stationary, and the piezoelectric driving device (4) returns to the initial state. Repeating this process can achieve the continuous linear stepping motion of the guide rail (3-1), the guide rail (3-2), and the guide rail (3-3). Further, the guide rail (3-1) drives the two-degree-of-freedom moving part (2-1) to move in the X direction, and the guide rail (3-2) and the guide rail (3-3) drive the one-degree-of-freedom moving part (2-2) to move in the Y direction, realizing the continuous stepping motion of the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2). Furthermore, the upper die body (1) connected to the two through the grooves is driven by the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) to move on the X-axis and the Y-axis. Further, since the contact surfaces between the upper die body (1) and the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) are slopes, when the two-degree-of-freedom moving part (2-1) and the one-degree-of-freedom moving part (2-2) approach each other, they can drive the upper die body (1) to move vertically upward, and then the upper die body (1) moves linearly along the Z-axis. In summary, the X, Y, and Z-axis movements of the upper die body can be realized. The involuntary movement of the patient's head during a computed tomography scan can be decomposed into component movements in the X, Y, and Z directions. Therefore, the movement of the upper die body can fully simulate the involuntary movement of the patient's head; (b) By adjusting the driving voltage amplitude and frequency of the piezoelectric stacks (4-2) and (4-3), the regulation of their movement speed can be achieved; (c) By applying a reverse sawtooth driving voltage to the piezoelectric stacks (4-2) and (4-3), reverse movement can be achieved.

[0019] The above are only the preferred examples of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. to the present invention should be included within the protection scope of the present invention.

Claims

1. A cranial motion artifact phantom for use in computed tomography, characterized in that: The invention comprises an upper mold body (1), a moving part (2), a guide rail (3-1), a guide rail (3-2), a piezoelectric drive device (4), and a base (5); the moving part (2) comprises a two-degree-of-freedom moving part (2-1) and a single-degree-of-freedom moving part (2-2); the piezoelectric drive device (4) comprises a displacement amplification hinge (4-1), a piezoelectric stack (4-2), a piezoelectric stack (4-3), an X-axis drive foot (4-4), and a Y-axis drive foot (4-5); the upper mold body (1) is placed above the moving part (2) through a groove; the moving part (2) is connected to the upper surface of the guide rail (3-1) and the guide rail (3-2) through screws; the guide rail (3-1) and the guide rail (3-2) are connected to the bottom by screws. The piezoelectric drive device (4) is connected to the upper surface of the base (5) by screws; the dual-degree-of-freedom motion component (2-1) is connected to the upper surface of the guide rail (3-1) by screws; the single-degree-of-freedom motion component (2-2) is connected to the upper surfaces of the guide rail (3-2) and the guide rail (3-3) by screws; the dual-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2) are interlocked with each other through grooves; the displacement amplification hinge (4-1) is connected to the upper surface of the base (5) by screws and is pre-tightened and installed at a corresponding position of the base (5); the piezoelectric stack (4-2) and the piezoelectric stack (4-3) are pre-tightened and installed in the grooves of the displacement amplification hinge (4-1).

2. The method for driving a cranial motion artifact phantom for computer tomography according to claim 1, characterized in that it comprises the following steps: (a) Due to the presence of the preload, a static friction force is generated between the X-axis driving foot (4-4) and the guide rail (3-1), and its direction is perpendicular to the plane of the guide rail (3-1) and points to the outside of the guide rail (3-1); a static friction force is generated between the Y-axis driving foot (4-5) and the guide rail (3-2), and its direction is perpendicular to the plane of the guide rail (3-2) and points to the outside of the guide rail (3-2); a continuous sawtooth driving voltage is applied to the piezoelectric stack (4-2) and the piezoelectric stack (4-3); when the voltage rises slowly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) slowly extend, causing the flexible part in the displacement amplification mechanism (4-1) to undergo elastic deformation; as the degree of elastic deformation gradually increases, the X-axis driving foot (4-4) and the guide rail are The friction force generated by (3-1) gradually increases in the component force parallel to the plane where the guide rail (3-1) is located, and the friction force generated by the Y-axis driving foot (4-5) and the guide rail (3-2) gradually increases in the component force parallel to the plane where the guide rail (3-2) is located. When the magnitude of the component force of the friction force exceeds the maximum static friction between the guide rail (3-1), the guide rail (3-2) and the X-axis driving foot (4-4) and the Y-axis driving foot (4-5), the guide rails (3-1) and (3-2) slide along the direction of the component force of the friction force, and the guide rail (3-3) also moves accordingly; when the driving voltage drops rapidly, the piezoelectric stack (4-2) and the piezoelectric stack (4-3) shorten rapidly, and the displacement amplification hinge (4-1) quickly returns to its initial state. , and during this process, the guide rails (3-1), (3-2), and (3-3) remain relatively still, and the piezoelectric drive device (4) returns to the initial state; repeating this process can realize continuous linear stepping motion of the guide rails (3-1), (3-2), and (3-3); further, the guide rail (3-1) drives the double-degree-of-freedom motion component (2-1) to move in the X direction, and the guide rails (3-2) and (3-3) drive the single-degree-of-freedom motion component (2-2) to move in the Y direction, thereby realizing continuous stepping motion of the double-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2), thereby making the upper mold body (1) connected to the two through the groove move in the double-degree-of-freedom motion component The upper mold body (1) can move vertically upward under the traction of the double-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2); further, since the contact surface between the upper mold body (1) and the double-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2) is a slope, when the double-degree-of-freedom motion component (2-1) and the single-degree-of-freedom motion component (2-2) are close to each other, the upper mold body (1) can be pulled to move vertically upward, thereby causing the upper mold body (1) to move linearly along the Z axis; in summary, the upper mold body can achieve X, Y, and Z three-axis movement; the involuntary movement of the patient's head during computer tomography can be decomposed into sub-movements in the three directions of X, Y, and Z, so the movement of the upper mold body can fully simulate the involuntary movement of the patient's head; (b) adjusting the driving voltage amplitude and frequency of the piezoelectric stack (4-2) and the piezoelectric stack (4-3) to achieve control of their movement speed; (c) Reverse motion can be achieved by applying a reverse sawtooth wave driving voltage to the piezoelectric stack (4-2) and the piezoelectric stack (4-3).

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