CT apparatus and CT apparatus control method

Abstract

To provide a CT apparatus and a CT apparatus control method that make it possible to improve the stability of data transmission in a capacitive coupling scheme.SOLUTION: A CT apparatus comprises: an X-ray source; a detector that detects X-rays and outputs detection data; a rotary portion that supports the X-ray source and the detector and rotates about a rotation axis; a stationary portion that holds the rotary portion rotatably; a transmission antenna that is provided in the rotation portion for transmitting detection data; a reception antenna that is disposed at a position facing a part of the transmission antenna; a rotation position detection unit that detects a rotation position of the rotary portion and outputs a detection value; a measurement unit that measures a relative relation between the transmission antenna and the reception antenna and outputs a measurement value; a displacement mechanism that displaces at least one of the transmission antenna and the reception antenna; and a processor that creates control data based on the detection value and the measurement value and performs displacement control that suppresses change in the relative relation by controlling the displacement mechanism based on the control data during transmission and reception of detection data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a CT apparatus and a method for controlling a CT apparatus. [Background technology]

[0002] A CT (Computed Tomography) device irradiates an object with X-rays while rotating a rotating part, in which an X-ray source and a detector are positioned opposite each other, around the object, and detects the X-rays that pass through the object with the detector. The detected data by the detector is transmitted from the rotating part to a stationary part that rotatably holds the rotating part, and image processing such as reconstruction processing is performed by a console or the like connected to the stationary part.

[0003] A non-contact data transmission device is used to transmit the detected data from the rotating part to the stationary part (see, for example, Patent Document 1). Known non-contact transmission methods include a capacitive coupling method using capacitive coupling and an optical transmission method using light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-244148 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the amount of data transmitted from the rotating part to the stationary part has been increasing. For example, in a PCCT (Photon Counting Computed Tomography) device that uses a photon counting detector that counts incident X-ray photons, the amount of detected data is large, so it is necessary to transmit large amounts of data from the rotating part to the stationary part at high speed.

[0006] When a capacitively coupled data transmission device is applied to a CT scanner, the transmitting antenna is installed on the rotating part and the receiving antenna is installed on the stationary part. In this case, the transmitting antenna and the receiving antenna must be positioned to ensure capacitive coupling. For example, the transmitting antenna extends along the outer or inner circumference of the rotating part, and the receiving antenna is positioned so as to face a part of the transmitting antenna.

[0007] In the capacitive coupling method, the transmission bandwidth is proportional to the coupling capacitance between the transmitting antenna and the receiving antenna. The coupling capacitance depends on the distance between the transmitting antenna and the receiving antenna and the area where the transmitting antenna and the receiving antenna overlap. In order to achieve stable data transmission using the capacitive coupling method, it is necessary to maintain a constant positional relationship between the transmitting antenna and the receiving antenna while the rotating part is rotating.

[0008] However, the rotating part may deform due to deterioration over time, etc. When the rotating part deforms, the relative relationship between the transmitting antenna and the receiving antenna changes as the rotating part rotates, which changes the coupling capacitance and reduces the stability of data transmission. In particular, when the distance between the transmitting antenna and the receiving antenna is reduced to increase the transmission speed, the deformation of the rotating part has a significant impact.

[0009] For example, in order to improve the stability of data transmission, it is conceivable to measure the distance between the transmitting antenna and the receiving antenna and adjust the position of the receiving antenna based on the measured value. However, it is not easy to measure the distance and displace the receiving antenna based on the measured value while the rotating part is rotating. For example, it takes time for the receiving antenna to displace, and it is conceivable that the stability of data transmission will be reduced because it cannot follow the rotation of the rotating part.

[0010] Therefore, an object of the technology disclosed herein is to provide a CT device and a control method for a CT device that can improve the stability of data transmission using a capacitive coupling method. [Means for solving the problem]

[0011] The CT device according to the disclosed technique includes an X-ray source that radiates X-rays toward a subject, a detector that detects the X-rays that have passed through the subject and outputs detection data, a rotating unit that supports the X-ray source and the detector and rotates around a rotation axis, a stationary unit that rotatably holds the rotating unit, a transmitting antenna that is provided on the rotating unit and transmits the detection data, a receiving antenna that is positioned opposite a part of the transmitting antenna, a rotation position detection unit that detects the rotation position of the rotating unit and outputs a detection value, a measurement unit that measures the relative relationship between the transmitting antenna and the receiving antenna and outputs a measurement value, a displacement mechanism that displaces at least one of the receiving antenna and the transmitting antenna, and a processor that creates control data based on the detection value and the measurement value, and performs displacement control that suppresses changes in the relative relationship by controlling the displacement mechanism based on the control data during transmission and reception of the detection data.

[0012] It is preferable that the processor creates relative relationship data representing the relationship between the relative relationship and the rotational position for one cycle based on the detected values ​​and measured values ​​for one cycle of rotation of the rotating part, and creates control data based on the relative relationship data.

[0013] The control data preferably represents the relationship between the displacement and rotational position of at least one of the receiving antenna and the transmitting antenna for one period.

[0014] The transmitting antenna is preferably arranged along the outer or inner circumference of the rotating part.

[0015] The relative relationship is the distance between the transmitting antenna and the receiving antenna, and the displacement mechanism preferably displaces the receiving antenna in a direction parallel to the rotation axis.

[0016] The relative relationship may be the degree of parallelism between the transmitting antenna and the receiving antenna, and the displacement mechanism may displace the receiving antenna around an axis parallel to the rotation axis.

[0017] The relative relationship may be an overlapping ratio between the transmitting antenna and the receiving antenna, and the displacement mechanism may displace the receiving antenna around an axis parallel to a direction perpendicular to the rotation axis.

[0018] a receiver for receiving the detection data via a receiving antenna; Preferably, the displacement mechanism displaces the receiving antenna by displacing the receiver.

[0019] The processor may correct the control data based on the measurement values ​​during the execution of the displacement control.

[0020] The processor may correct the control data based on the difference between the acquired measurement value and the measurement value one cycle ago, a certain time ago, or a certain rotation angle ago.

[0021] A control method for a CT device according to the disclosed technology includes an X-ray source that radiates X-rays toward a subject, a detector that detects X-rays that have passed through the subject and output detection data, a rotating unit that supports the X-ray source and the detector and rotates around a rotation axis, a stationary unit that rotatably holds the rotating unit, a transmitting antenna provided on the rotating unit for transmitting the detection data, a receiving antenna positioned opposite a part of the transmitting antenna, a rotation position detection unit that detects the rotation position of the rotating unit and outputs a detection value, a measurement unit that measures the relative relationship between the transmitting antenna and the receiving antenna and outputs a measurement value, and a displacement mechanism that displaces at least one of the receiving antenna and the transmitting antenna, in which a processor creates control data based on the detection value and the measurement value, and performs displacement control that suppresses changes in the relative relationship by controlling the displacement mechanism based on the control data during transmission and reception of the detection data. [Effects of the Invention]

[0022] According to the technology of the present disclosure, it is possible to provide a CT device and a control method for a CT device that can improve the stability of data transmission using a capacitive coupling method. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a CT device. [Figure 2]FIG. 2 is a diagram illustrating a schematic configuration of a gantry. [Figure 3] FIG. 1 is a diagram illustrating a configuration of a data transmission device. [Figure 4] 1A and 1B are diagrams illustrating schematic configuration examples of a transmitting antenna and a receiving antenna. [Figure 5] 1A and 1B are diagrams illustrating schematic configuration examples of a transmitting antenna and a receiving antenna. [Figure 6] FIG. 2 is a diagram illustrating an example of the configuration of a displacement control unit. [Figure 7] FIG. 10 is a diagram illustrating an example of the flow of a control data creation process. [Figure 8] FIG. 10 is a diagram illustrating an example of relative relationship data. [Figure 9] FIG. 10 is a diagram illustrating an example of control data. [Figure 10] FIG. 10 is a diagram illustrating an example of a flow of displacement control. [Figure 11] FIG. 10 is a diagram showing the configuration of a measurement unit and a displacement mechanism according to a first modified example. [Figure 12] FIG. 10 is a diagram illustrating parallelism. [Figure 13] FIG. 10 is a diagram illustrating an overlap rate. [Figure 14] FIG. 10 is a diagram showing an example of the flow of displacement control according to the second modified example. [Figure 15] FIG. 10 is a diagram schematically illustrating an example of the configuration of a transmitting antenna and a receiving antenna according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 shows a schematic configuration of a CT device 1. The CT device 1 is composed of a gantry 2, a bed 3, and a console 4. Note that the CT device 1 is not limited to a CT device having a charge integration type detector, and may be a PCCT device having a photon counting type detector that counts incident X-ray photons.

[0025] The gantry 2 has an opening 2A in the center through which a part of the bed 3 is inserted. Inside the gantry 2, there are provided an X-ray source 10 that radiates X-rays to the subject H, and a detector 20 that detects the X-rays that have passed through the subject H to generate a radiological image. The X-ray source 10 and the detector 20 are configured to be rotatable along the annular shape of the gantry 2 while maintaining a mutually opposing positional relationship.

[0026] The bed 3 has a top plate 3A on which the subject H is placed, a base 3B that supports the top plate 3A, and a drive unit 3C that moves the top plate 3A back and forth in the direction of arrow A, and is configured to be able to move the subject H. The top plate 3A can be slid in the direction of arrow A relative to the base 3B by the drive unit 3C. When imaging the subject H, the top plate 3A slides and is inserted into the opening 2A of the gantry 2. This allows the subject H to be transported into the opening 2A.

[0027] The console 4 is a computer configured to include a processor 40 such as a CPU (Central Processing Unit), a display 41 such as a liquid crystal display, and an input device 42 such as a keyboard and a mouse.

[0028] 2 shows a schematic configuration of the gantry 2. The gantry 2 is a device that irradiates X-rays onto the subject H and collects detection data of the X-rays that have passed through the subject H. The gantry 2 has a rotating section 2B and a stationary section 2C. A data transmission device 5 is provided between the rotating section 2B and the stationary section 2C for transmitting data from the rotating section 2B to the stationary section 2C in a non-contact manner.

[0029] The rotating unit 2B supports the X-ray source 10, the detector 20, and the data collecting unit 21. The rotating unit 2B is a disk-shaped rotating body that supports the X-ray source 10 and the detector 20 so that they can rotate around the rotation axis C while facing each other. The opening 2A described above is formed in the center of the rotating unit 2B. The data collecting unit 21 is attached to the detector 20. The rotating unit 2B rotates in a circular orbit centered on the rotation axis C. The subject H is positioned so that the body axis is approximately aligned with the rotation axis C.

[0030] The X-ray source 10 includes an X-ray tube 11 and an aperture 12. The X-ray tube 11 generates X-rays and irradiates the generated X-rays onto the subject H. The aperture 12 shapes the X-rays generated by the X-ray tube 11 into a cone beam having a predetermined fan angle and cone angle.

[0031] The detector 20 is configured to include a plurality of X-ray detection elements. The detector 20 detects data (hereinafter referred to as "detection data") indicating the intensity distribution of X-rays transmitted through the subject H using the plurality of X-ray detection elements, and outputs the detection data. For example, the detector 20 is a two-dimensional X-ray detector in which a plurality of X-ray detection elements are arranged in two mutually orthogonal directions (i.e., slice direction and channel direction). The detector 20 can image a three-dimensional imaging region having a width in the slice direction in one scan rotation. The slice direction is a direction parallel to the rotation axis C, and the channel direction is a rotation direction around the rotation axis C.

[0032] The data collection unit 21 is a DAS (Data Acquisition System) that collects the detection data output from the detector 20. The data collection unit 21 also converts the collected detection data into digital data and transmits it to the data transmission device 5.

[0033] The stationary portion 2C is a holding member that rotatably holds the rotating portion 2B. The stationary portion 2C has a high voltage generating portion 6, an aperture driving portion 7, and a gantry driving portion 8.

[0034] The high voltage generation unit 6 applies a high voltage to the X-ray tube 11, causing the X-ray tube 11 to generate X-rays. The iris driver 7 drives the iris 12 so that the X-rays generated by the X-ray tube 11 have a predetermined shape. The gantry driver 8 drives the rotation unit 2B.

[0035] The high voltage generating unit 6, the aperture driving unit 7, and the gantry driving unit 8 are controlled by the console 4. The console 4 also controls the driving unit 3C of the bed 3.

[0036] 3 shows the configuration of the data transmission device 5. The data transmission device 5 has a first memory 50, a transmitter 51, a transmitting antenna 52, a receiving antenna 53, a receiver 54, a second memory 55, and a transmission control unit 56. The first memory 50, the transmitter 51, and the transmitting antenna 52 are provided on the rotating unit 2B. The receiving antenna 53, the receiver 54, the second memory 55, and the transmission control unit 56 are provided on the stationary unit 2C.

[0037] The first memory 50 stores the detection data collected by the data collection unit 21. The transmitter 51 is a transmission circuit that transmits the detection data stored in the first memory 50 via a transmission antenna 52. Specifically, the transmitter 51 generates a high-frequency electrical signal by modulating the amplitude, phase, frequency, etc. of a carrier wave based on the detection data, and supplies the generated signal to the transmission antenna 52. The transmission antenna 52 emits the electrical signal supplied from the transmitter 51 as a radio wave.

[0038] The receiver 54 is a receiving circuit that receives, via the receiving antenna 53, the detection data transmitted from the transmitter 51 via the transmitting antenna 52 and stores the data in the second memory 55. Specifically, the receiving antenna 53 detects the radio waves emitted from the transmitting antenna 52 to generate an electrical signal and supplies the generated electrical signal to the receiver 54. The receiver 54 demodulates the electrical signal supplied from the receiving antenna 53 to convert it into detection data and stores the data in the second memory 55.

[0039] The transmission control unit 56 controls the first memory 50, the transmitter 51, the transmitting antenna 52, the receiving antenna 53, the receiver 54, and the second memory 55 to transmit and receive the detected data (hereinafter also referred to as data transmission). The transmission control unit 56 also controls the second memory 55 to transmit the detected data to the console 4.

[0040] The data transmission device 5 also has a rotational position detection unit 60, a measurement unit 61, a displacement mechanism 62, and a displacement control unit 63. For example, the rotational position detection unit 60 is provided in the rotating unit 2B, and the measurement unit 61, the displacement mechanism 62, and the displacement control unit 63 are provided in the stationary unit 2C.

[0041] The rotational position detection unit 60 detects the rotational position of the rotating unit 2B. For example, the rotational position detection unit 60 is an optical, magnetic, or mechanical rotary encoder. The rotational position is a rotation angle from a reference angle. The detection value of the rotational position detected by the rotational position detection unit 60 is transmitted to the displacement control unit 63 via wire or wirelessly.

[0042] The measurement unit 61 is a measurement sensor that measures the relative relationship between the transmitting antenna 52 and the receiving antenna 53 and supplies the measurement value to the displacement control unit 63. In this embodiment, the measurement unit 61 measures the distance L (see FIG. 4) between the transmitting antenna 52 and the receiving antenna 53. For example, the measurement unit 61 is a laser displacement meter, and is fixed near the receiving antenna 53. The measurement unit 61 measures the distance L between the transmitting antenna 52 and the receiving antenna 53 by measuring the displacement of the transmitting antenna 52.

[0043] The measuring unit 61 may be any device capable of measuring the relative relationship between the transmitting antenna 52 and the receiving antenna 53, and may be configured with an optical device such as a dial gauge or a camera. The measuring unit 61 may also be a gyro sensor provided inside the rotating unit 2B. Furthermore, it is also possible to measure the distance L between the transmitting antenna 52 and the receiving antenna 53 based on the strength of the radio waves emitted from the transmitting antenna 52 detected by the receiving antenna 53.

[0044] The displacement mechanism 62 is a mechanism that changes the relative position of the receiving antenna 53 with respect to the transmitting antenna 52. The receiving antenna 53 is fixed to the receiver 54. Therefore, the displacement mechanism 62 is provided on the receiver 54, and displaces the receiving antenna 53 with respect to the transmitting antenna 52 by displacing the receiver 54. In the present disclosure, displacement includes not only translational movement of an object but also rotational movement.

[0045] In this embodiment, the displacement mechanism 62 displaces (i.e., translates) the receiving antenna 53 so as to change the distance L between the transmitting antenna 52 and the receiving antenna 53. For example, the displacement mechanism 62 is an actuator having a piezoelectric motor, a stepping motor, a servo motor, or the like.

[0046] The displacement control unit 63 controls the displacement mechanism 62 while the rotating unit 2B is rotating, thereby performing displacement control to suppress changes in the relative relationship between the transmitting antenna 52 and the receiving antenna 53. In this embodiment, the displacement control unit 63 controls the displacement mechanism 62 to displace the receiving antenna 53 in the radial direction of the rotating unit 2B (the Z direction shown in FIG. 3), thereby suppressing changes in the distance L between the transmitting antenna 52 and the receiving antenna 53 during rotation.

[0047] Furthermore, before performing displacement control, the displacement control unit 63 acquires the detection value of the rotational position detected by the rotational position detection unit 60 while the rotating unit 2B is rotating, and the measurement value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 measured by the measurement unit 61. Based on the acquired data representing the relationship between the rotational position and the relative relationship, the displacement control unit 63 creates control data for canceling out changes in the relative relationship between the transmitting antenna 52 and the receiving antenna 53. Then, the displacement control unit 63 performs displacement control using the created control data.

[0048] 4 shows a schematic configuration example of the transmitting antenna 52 and the receiving antenna 53. The transmitting antenna 52 is composed of a conductive member arranged along the outer periphery 2D of the rotating part 2B, and both ends of the conductive member are connected to the transmitter 51. That is, the transmitting antenna 52 is part of a transmitting circuit (not shown) and has a pattern shape such as a ring shape, an arc shape, or a serpentine shape arranged along the outer periphery 2D centered on the rotation axis C. The outer periphery 2D refers to the outer portion of the rotating part 2B. In this embodiment, the outer periphery 2D is the outer periphery surface centered on the rotation axis C, and the transmitting antenna 52 is arranged on the outer periphery surface and exposed.

[0049] The receiving antenna 53 is disposed at a position facing a part of the transmitting antenna 52 disposed along the outer circumferential portion 2D of the rotating portion 2B. The receiving antenna 53 is made of a conductive member disposed on the surface 54A of the receiver 54. As shown in Fig. 5, the receiving antenna 53 is part of a receiving circuit (not shown), and is disposed facing and parallel to a part of the transmitting antenna 52, and has a pattern shape such as a straight line, an arc, or a serpentine shape.

[0050] 4 and 5, the direction parallel to the rotation axis C is defined as the Y direction, the direction perpendicular to the Y direction in which the transmitting antenna 52 and the receiving antenna 53 face each other is defined as the Z direction, and the direction perpendicular to the Y direction and the Z direction is defined as the X direction. The receiving antenna 53 is parallel to the X direction. Furthermore, the tangent line of the transmitting antenna 52 in the direction perpendicular to the rotation axis C at the portion facing the receiving antenna 53 is approximately parallel to the X direction.

[0051] 6 shows an example of the configuration of the displacement control unit 63. The displacement control unit 63 has a processor 63A such as a CPU (Central Processing Unit), a non-volatile storage 63B, and a memory 63C as a temporary storage area. A program 64 and control data 65 are stored in the non-volatile storage 63B.

[0052] The displacement control section 63 executes processing based on the program 64 that the processor 63A reads into the memory 63C, thereby performing a control data creation process for creating control data 65 and the above-mentioned displacement control.

[0053] 7 shows an example of the flow of the control data creation process. In the control data creation process, first, the displacement control unit 63 rotates the rotation unit 2B via the console 4 (step S10). Next, the displacement control unit 63 acquires a detected value of the rotation position from the rotation position detection unit 60 (step S11). The displacement control unit 63 also acquires a measured value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 from the measurement unit 61 (step S12). Note that steps S11 and S12 may be executed in parallel.

[0054] Next, the displacement control unit 63 determines whether one rotation cycle of the rotating unit 2B has elapsed (step S13). If one rotation cycle of the rotating unit 2B has not elapsed (step S13: NO), the displacement control unit 63 returns the process to step S11. That is, the displacement control unit 63 executes steps S11 and S12 at predetermined time intervals until one rotation cycle of the rotating unit 2B has elapsed.

[0055] When one rotation cycle of the rotating unit 2B has elapsed (step S13: YES), the displacement control unit 63 creates relative relationship data representing the relationship between the relative relationship and the rotation position for one cycle based on the detected values ​​of the rotation position for one cycle and the measured values ​​of the relative relationship (step S14). Then, the displacement control unit 63 creates control data 65 for canceling out the change in the relative relationship based on the relative relationship data (step S15), and records the created control data 65 in storage 63B (step S16). This completes the control data creation process.

[0056] The displacement control section 63 may create the relative relationship data by performing an averaging process or the like on the data of the detected values ​​of the rotational position for two or more periods and the measured values ​​of the relative relationship.

[0057] Furthermore, it is preferable that the displacement control unit 63 perform the control data creation process when the subject H is not placed on the bed 3. For example, the displacement control unit 63 may perform the control data creation process during warm-up after the CT apparatus 1 is started up, during preparation for imaging, etc. Alternatively, the control data creation process may be performed when the subject H is placed on the bed 3. For example, the displacement control unit 63 may perform the control data creation process at one or more timings while the CT apparatus 1 is imaging the subject H.

[0058] Fig. 8 shows an example of relative relationship data. The relative relationship data shown in Fig. 8 indicates the relationship between the distance L between the transmitting antenna 52 and the receiving antenna 53 and the rotational position. L0 is the ideal distance for stable data transmission. When the rotating part 2B is deformed due to deterioration over time or the like, the distance L between the transmitting antenna 52 and the receiving antenna 53 changes from the ideal distance L0.

[0059] Fig. 9 shows an example of the control data 65. The control data 65 shown in Fig. 9 shows the relationship between the displacement amount D of the receiving antenna 53 displaced by the displacement mechanism 62 and the rotational position. The displacement amount D is the amount of drive of the receiving antenna 53 in the Z direction required to suppress changes in the distance L between the transmitting antenna 52 and the receiving antenna 53 and to set the distance L to the ideal distance L0.

[0060] 10 shows an example of the flow of displacement control. In displacement control, first, the displacement control unit 63 reads the control data 65 from the storage 63B to the memory 63C (step S20). Next, the displacement control unit 63 determines whether or not the data transmission device 5 has started transmitting the detected data (step S21). If the data transmission has not started (step S21: NO), the displacement control unit 63 repeats the determination.

[0061] When data transmission has started (step S21: YES), the displacement control unit 63 acquires the detected value of the rotational position from the rotational position detection unit 60 (step S22). Furthermore, the displacement control unit 63 determines the displacement amount D corresponding to the rotational position based on the control data 65, and controls the displacement mechanism 62 based on the displacement amount D (step S23).

[0062] The displacement control unit 63 determines whether the data transmission has ended (step S24). If the data transmission has not ended (step S24: NO), the displacement control unit 63 returns the process to step S22. That is, the displacement control unit 63 executes steps S22 and S23 at predetermined time intervals until the data transmission ends. If the data transmission has ended (step S24: YES), the displacement control unit 63 ends the displacement control.

[0063] As described above, in this embodiment, the receiving antenna 53 is displaced so as to suppress changes in the distance L between the transmitting antenna 52 and the receiving antenna 53 based on the control data 65 created in advance, thereby stabilizing the coupling capacitance between the transmitting antenna 52 and the receiving antenna 53. In this embodiment, the control data 65 created in advance is used, so there is no need to perform a calculation to determine the displacement amount D during rotation, and the ability of the receiving antenna 53 to follow the rotation of the rotating part 2B is improved. Therefore, according to this embodiment, the stability of data transmission using the capacitive coupling method can be improved.

[0064] Various modifications of the above embodiment will be described below.

[0065] [First Modification] In the above embodiment, the measuring unit 61 measures the distance L between the transmitting antenna 52 and the receiving antenna 53 as the relative relationship between the transmitting antenna 52 and the receiving antenna 53, but it may measure a relative relationship other than the distance L. Also, in the above embodiment, the displacement mechanism 62 displaces the receiving antenna 53 in the radial direction of the rotating unit 2B (i.e., the Z direction), but it may displace it in a direction other than the Z direction.

[0066] 11 shows the configuration of a measurement unit 61 and a displacement mechanism 62 according to a first modified example. In this modified example, the measurement unit 61 includes a first measurement unit 61A, a second measurement unit 61B, and a third measurement unit 61C. The displacement mechanism 62 includes a first displacement mechanism 62A, a second displacement mechanism 62B, and a third displacement mechanism 62C.

[0067] The first measuring unit 61A has the same configuration as the measuring unit 61 in the above embodiment, and measures the distance L between the transmitting antenna 52 and the receiving antenna 53.

[0068] The second measuring unit 61B measures the parallelism between the transmitting antenna 52 and the receiving antenna 53. As shown in FIG. 12, the portion of the transmitting antenna 52 that faces the receiving antenna 53 is almost flat. Specifically, the second measuring unit 61B measures the tilt angle α of the portion of the transmitting antenna 52 that faces the receiving antenna 53 with respect to the transmitting antenna 52. The tilt angle α is an angle around an axis parallel to the Y direction. The smaller the tilt angle α, the higher the parallelism and the more stable the data transmission.

[0069] For example, the second measurement unit 61B is a plurality of laser displacement meters arranged in the X direction. The second measurement unit 61B measures the distance between the transmitting antenna 52 and the receiving antenna 53 at a plurality of positions in the X direction to measure the tilt angle α. Note that the second measurement unit 61B may be a camera that captures images of the transmitting antenna 52 and the receiving antenna 53 from the Y direction, and may measure the tilt angle α based on the captured images.

[0070] The third measurement unit 61C measures the overlap rate between the transmitting antenna 52 and the receiving antenna 53. As shown in FIG. 13, the transmitting antenna 52 and the receiving antenna 53 almost overlap when viewed from the Z direction, but the overlap rate decreases when the transmitting antenna 52 is tilted in the XY plane. The third measurement unit 61C measures the tilt angle β of the portion of the transmitting antenna 52 that faces the receiving antenna 53 relative to the transmitting antenna 52. The tilt angle β is the angle around an axis parallel to the Z direction. The smaller the tilt angle β, the higher the overlap rate and the more stable the data transmission.

[0071] For example, the third measurement unit 61C is a camera that captures an image of the transmitting antenna 52 from the Z direction. The third measurement unit 61C measures the tilt angle β based on the captured image.

[0072] The first displacement mechanism 62A has the same configuration as the displacement mechanism 62 of the above embodiment, and displaces the receiving antenna 53 in the Z direction so that the distance L between the transmitting antenna 52 and the receiving antenna 53 changes.

[0073] The second displacement mechanism 62B displaces (i.e., rotates) the receiving antenna 53 around an axis parallel to the Y axis so as to change the tilt angle α. For example, the second displacement mechanism 62B is a rotary actuator. For example, the second displacement mechanism 62B is fixed to the receiver 54, and displaces the receiving antenna 53 by displacing the receiver 54.

[0074] The third displacement mechanism 62C displaces (i.e., rotates) the receiving antenna 53 around an axis parallel to the Z axis so as to change the tilt angle β. For example, the third displacement mechanism 62C is a rotary actuator. For example, the third displacement mechanism 62C is fixed to the receiver 54, and displaces the receiving antenna 53 by displacing the receiver 54.

[0075] In this modification, the displacement control unit 63 independently performs the first displacement control, the second displacement control, and the third displacement control while the rotating unit 2B is rotating. The first displacement control is the same as that in the above embodiment, in which the first displacement mechanism 62A is controlled based on the rotational position detected by the rotational position detection unit 60 and the measurement value measured by the first measurement unit 61A.

[0076] The second displacement control is a displacement control that controls the second displacement mechanism 62B based on the detection value of the rotational position detected by the rotational position detection unit 60 and the measurement value measured by the second measurement unit 61B. The third displacement control is a displacement control that controls the third displacement mechanism 62C based on the detection value of the rotational position detected by the rotational position detection unit 60 and the measurement value measured by the third measurement unit 61C.

[0077] As in the above embodiment, the displacement control unit 63 generates first relative relationship data, second relative relationship data, and third relative relationship data before executing the first displacement control, second displacement control, and third displacement control. The first relative relationship data is the same relative relationship data as in the above embodiment, which indicates the relationship between the distance L between the transmitting antenna 52 and the receiving antenna 53 and the rotational position.

[0078] The second relative relationship data is relative relationship data that indicates the relationship between the parallelism (i.e., tilt angle α) and the rotation position. The third relative relationship data is relative relationship data that indicates the relationship between the overlap rate (i.e., tilt angle β) and the rotation position.

[0079] The displacement control unit 63 also performs a control data creation process to create first control data, second control data, and third control data based on the first relative relationship data, second relative relationship data, and third relative relationship data. As in the above embodiment, the first control data indicates the relationship between the displacement amount D of the receiving antenna 53 in the Z direction caused by the first displacement mechanism 62A and the rotational position.

[0080] The second control data indicates the relationship between the amount of displacement (i.e., amount of rotation) of the receiving antenna 53 around an axis parallel to the Y axis, which is displaced by the second displacement mechanism 62B, and the rotation position. The third control data indicates the relationship between the amount of displacement (i.e., amount of rotation) of the receiving antenna 53 around an axis parallel to the Z axis, which is displaced by the third displacement mechanism 62C, and the rotation position.

[0081] The first control data, second control data, and third control data each represent the relationship between the rotational position and displacement amount for one cycle of the rotating part 2B. Note that the displacement control part 63 may create the first relative relationship data, second relative relationship data, and third relative relationship data by performing an averaging process or the like on data of the detected values ​​of the rotational position for two or more cycles and the measured values ​​of the relative relationship.

[0082] The timing of execution of the control data creation process in this modified example is the same as in the above embodiment.

[0083] The technology of the present disclosure may be configured to execute one or more of the first displacement control, the second displacement control, and the third displacement control.

[0084] [Second Modification] In the above embodiment, the displacement control unit 63 performs displacement control based on control data 65 created in advance. However, the control data 65 may be corrected based on measurement values ​​measured by the measurement unit 61 while displacement control is being performed. After the control data 65 is created, changes in environmental conditions such as temperature, humidity, and atmospheric pressure, or changes in device conditions such as the rotation speed of the rotating unit 2B, scan time, and age of the device, may cause the control data 65 to deviate from the optimal value. This may result in a decrease in the stability of data transmission. By correcting the control data 65 based on measurement values ​​while displacement control is being performed, as in this modification, the effects of changes in the environmental conditions or device conditions described above are suppressed, improving the stability of data transmission.

[0085] 14 shows an example of the flow of displacement control according to Modification 2. The flow of displacement control according to this modification differs from the flow of displacement control according to the above embodiment only in that steps S30 and S31 are added between steps S22 and S23.

[0086] In this modification, the displacement control unit 63 acquires a detected value of the rotational position from the rotational position detection unit 60 in step S22, and then acquires a measurement value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 from the measurement unit 61 (step S30). Next, the displacement control unit 63 corrects the control data 65 based on the acquired measurement value (step S31). Specifically, the displacement control unit 63 corrects the amount of displacement corresponding to the rotational position acquired in step S22 based on the difference between the measurement value acquired in step S30 and the measurement value acquired one cycle ago, a fixed time ago, or a fixed rotation angle ago. For example, the displacement control unit 63 performs the correction using an amount of displacement (i.e., a control amount) calculated by PID (Proportional-Integral-Differential) control, moving average, feedback control, feedforward control, or the like.

[0087] Thereafter, the displacement control unit 63 controls the displacement mechanism 62 based on the amount of displacement corrected in step S31 (step S23).

[0088] The second modification may be applied to each of the first displacement control, the second displacement control, and the third displacement control described in the first modification.

[0089] The technology disclosed herein uses the displacement control described above to maintain a constant relative relationship between the transmitting antenna 52 and the receiving antenna 53. This constant value includes a tolerance. It is preferable to change this tolerance depending on, for example, the transmission bandwidth of the data transmission. When the transmission speed is high, it is preferable to maintain the relative relationship between the transmitting antenna 52 and the receiving antenna 53 at a constant value with high precision, so it is preferable to make the tolerance smaller than when the transmission speed is low.

[0090] [Third Modification] In the above embodiment, the transmitting antenna 52 is arranged so as to be exposed to the outside of the rotating part 2B, but the transmitting antenna 52 may also be arranged inside the rotating part 2B.

[0091] FIG. 15 shows a schematic configuration example of a transmitting antenna 52 and a receiving antenna 53 according to a third modified example. In this modified example, the transmitting antenna 52 is part of a transmitting circuit (not shown) and has a pattern shape such as a ring shape, an arc shape, or a serpentine shape arranged along an inner circumferential portion 2E centered on the rotation axis C. The inner circumferential portion 2E refers to a portion inside the outer circumferential surface of the rotating portion 2B. In this modified example, the inner circumferential portion 2E is a region near the outer circumferential surface centered on the rotation axis C, and the transmitting antenna 52 is not exposed from the outer circumferential surface. The configuration of the receiving antenna 53 is the same as that of the above embodiment.

[0092] [Other variations] In the above embodiment, the displacement mechanism 62 is configured to displace the receiving antenna 53, but it may also be configured to displace the transmitting antenna 52. Furthermore, the displacement mechanism 62 may also be configured to displace both the receiving antenna 53 and the transmitting antenna 52. That is, the displacement mechanism 62 only needs to be configured to displace at least one of the receiving antenna 53 and the transmitting antenna 52. Furthermore, the control data 65 only needs to be data that represents the relationship between the amount of displacement and the rotational position of at least one of the receiving antenna 53 and the transmitting antenna 52 for one period.

[0093] Furthermore, in the above embodiment, the displacement control section 63 is provided inside the stationary section 2C, but the displacement control section 63 may also be provided outside the stationary section 2C, such as inside the console 4. The following various processors can be used as the hardware structure of the displacement control section 63. As described above, the various processors include a CPU, which is a general-purpose processor that executes software (programs) and functions as various processing sections, as well as dedicated electrical circuits, such as a PLD (Programmable Logic Device), which is a processor whose circuit configuration can be changed after manufacture, such as an FPGA (Field Programmable Gate Array), and an ASIC (Application Specific Integrated Circuit), which is a processor having a circuit configuration designed specifically for executing specific processing.

[0094] The displacement control unit 63 may be configured with one of these various processors, or may be configured with a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs or a combination of a CPU and an FPGA).

[0095] From the above description, the technology described in the following supplementary paragraphs can be understood. [Additional note 1] an X-ray source that emits X-rays toward the subject; a detector that detects the X-rays that have passed through the subject and outputs detection data; a rotating part that supports the X-ray source and the detector and rotates around a rotation axis; a stationary part that rotatably holds the rotating part; a transmitting antenna provided on the rotating part for transmitting the detection data; a receiving antenna disposed at a position opposite to a part of the transmitting antenna; a rotational position detection unit that detects the rotational position of the rotating unit and outputs a detection value; a measurement unit that measures the relative relationship between the transmitting antenna and the receiving antenna and outputs a measurement value; a displacement mechanism for displacing at least one of the receiving antenna and the transmitting antenna; a processor that creates control data based on the detected values ​​and the measured values, and executes displacement control to suppress changes in the relative relationship by controlling the displacement mechanism based on the control data during transmission and reception of the detected data; A CT device equipped with [Additional note 2] The processor: creating relative relationship data representing a relationship between the relative relationship and the rotation position for one rotation period based on the detected values ​​and the measured values ​​for one rotation period of the rotating part, and creating the control data based on the relative relationship data; 1. A CT device as described in appended item 1. [Additional note 3] the control data represents a relationship between a displacement amount of at least one of the receiving antenna and the transmitting antenna for one period and the rotational position; 1. A CT device as described in appended item 2. [Additional note 4] The transmitting antenna is arranged along the outer periphery or the inner periphery of the rotating part. 1. A CT apparatus according to claim 1, wherein the CT apparatus is a CT scanner. [Additional note 5] the relative relationship is a distance between the transmitting antenna and the receiving antenna, the displacement mechanism displaces the receiving antenna in a direction parallel to the rotation axis; CT device according to appended item 4. [Additional note 6] the relative relationship is the parallelism between the transmitting antenna and the receiving antenna, the displacement mechanism displaces the receiving antenna around an axis parallel to the rotation axis; CT device according to appended item 4. [Additional note 7] the relative relationship is an overlapping ratio between the transmitting antennas and the receiving antennas, the displacement mechanism displaces the receiving antenna around an axis parallel to a direction orthogonal to the rotation axis; CT device according to appended item 4. [Additional note 8] a receiver for receiving the detection data via the receiving antenna; the displacement mechanism displaces the receiving antenna by displacing the receiver; 10. The CT device according to claim 5, wherein the CT device is a CT scanner. [Additional note 9] the processor corrects the control data based on the measurement value during execution of the displacement control. 10. The CT device according to any one of claims 1 to 8. [Additional Note 10] the processor corrects the control data based on a difference value between the measurement value obtained one cycle ago, a certain time ago, or a certain rotation angle ago and the measurement value obtained. 10. The CT device according to claim 9. [Explanation of symbols]

[0096] 1 CT device 2 Gantry 2A aperture 2B Rotating part 2C Stationary part 2D outer periphery 2E Inner circumference 3 berths 3A Top plate 3B base 3C Drive Unit 4 Console 5 Data transmission equipment 6 High voltage generator 7 Aperture drive unit 8 Gantry drive unit 10 X-ray source 11 X-ray tube 12 apertures 20 detectors 21 Data Collection Department 40 processors 41 Display 42 Input Devices 50 memory 51 Transmitter 52 transmitting antenna 53 Receiving antenna 54 Receiver 54A surface 55 memory 56 Transmission control section 60 Rotational position detection unit 61 Measurement section 61A First Measurement Section 61B Second Measurement Section 61C 3rd Measurement Section 62 Displacement Mechanism 62A First displacement mechanism 62B Second displacement mechanism 62C Third displacement mechanism 63 Displacement control section 63A processor 63B Storage 63C Memory 64 Programs 65 Control Data C rotation axis H Subject

Claims

1. an X-ray source that emits X-rays toward the subject; a detector that detects X-rays transmitted through the subject and outputs detection data; a rotating part that supports the X-ray source and the detector and rotates around a rotation axis; a stationary part that rotatably holds the rotating part; a transmitting antenna provided on the rotating part for transmitting the detection data; a receiving antenna disposed at a position opposite to a part of the transmitting antenna; a rotational position detection unit that detects the rotational position of the rotating unit and outputs a detection value; a measurement unit that measures the relative relationship between the transmitting antenna and the receiving antenna and outputs a measurement value; a displacement mechanism for displacing at least one of the receiving antenna and the transmitting antenna; a processor that creates control data based on the detected value and the measured value, and executes displacement control to suppress changes in the relative relationship by controlling the displacement mechanism based on the control data during transmission and reception of the detected data; A CT device comprising:

2. The processor: creating relative relationship data representing a relationship between the relative relationship and the rotation position for one rotation period based on the detected values ​​and the measured values ​​for one rotation period of the rotating part, and creating the control data based on the relative relationship data; The CT device according to claim 1.

3. the control data represents a relationship between a displacement amount of at least one of the receiving antenna and the transmitting antenna for one period and the rotation position; The CT apparatus according to claim 2.

4. The transmitting antenna is arranged along the outer periphery or the inner periphery of the rotating part. The CT device according to claim 1.

5. the relative relationship is a distance between the transmitting antenna and the receiving antenna, the displacement mechanism displaces the receiving antenna in a direction parallel to the rotation axis; 5. The CT apparatus according to claim 4.

6. the relative relationship is the parallelism between the transmitting antenna and the receiving antenna, the displacement mechanism displaces the receiving antenna around an axis parallel to the rotation axis; 5. The CT apparatus according to claim 4.

7. the relative relationship is an overlapping ratio between the transmitting antennas and the receiving antennas, the displacement mechanism displaces the receiving antenna around an axis parallel to a direction orthogonal to the rotation axis; The CT apparatus according to claim 4.

8. a receiver for receiving the detection data via the receiving antenna; the displacement mechanism displaces the receiving antenna by displacing the receiver; 8. The CT apparatus according to claim 5, wherein the first and second electrodes are arranged parallel to each other.

9. the processor corrects the control data based on the measurement value during execution of the displacement control. The CT device according to claim 1.

10. the processor corrects the control data based on a difference value between the measurement value obtained one cycle ago, a certain time ago, or a certain rotation angle ago and the acquired measurement value. The CT apparatus according to claim 9.

11. an X-ray source that emits X-rays toward the subject; a detector that detects X-rays transmitted through the subject and outputs detection data; a rotating part that supports the X-ray source and the detector and rotates around a rotation axis; a stationary part that rotatably holds the rotating part; a transmitting antenna provided on the rotating part for transmitting the detection data; a receiving antenna disposed at a position opposite to a part of the transmitting antenna; a rotational position detection unit that detects the rotational position of the rotating unit and outputs a detection value; a measurement unit that measures the relative relationship between the transmitting antenna and the receiving antenna and outputs a measurement value; a displacement mechanism for displacing at least one of the receiving antenna and the transmitting antenna; A control method for a CT apparatus comprising: a processor creates control data based on the detected value and the measured value, and performs displacement control to suppress changes in the relative relationship by controlling the displacement mechanism based on the control data while transmitting and receiving the detected data. A method for controlling a CT device.

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