CT (Computed Tomography) device and control method of CT device

Abstract

The invention provides a CT device and a control method of the CT device, which can improve the stability of data transmission based on a capacitive coupling method. A CT device is provided with: an X-ray source; a detector that detects the X-rays and outputs detection data; a rotation unit that supports the X-ray source and the detector and rotates about a rotation axis; a stationary part that rotatably holds the rotating part; a transmission antenna which is provided to the rotation unit and transmits the detection data; a reception antenna disposed at a position facing a part of the transmission antenna; a rotation position detection unit that detects the rotation position of the rotation unit and outputs a detection value; a measurement unit that measures the relative relationship between the transmission antenna and the reception antenna and outputs a measurement value; a displacement mechanism that displaces at least one of the reception antenna and the transmission antenna; and a processor that creates control data on the basis of the detected value and the measured value, and controls the displacement mechanism on the basis of the control data during transmission and reception of the detected data, thereby performing displacement control that suppresses a change in the relative relationship.

Description

Technical Field

[0001] This invention relates to a CT device and a control method for the CT device. Background Technology

[0002] A CT (Computed Tomography) device irradiates a patient with X-rays while rotating a rotating section positioned opposite the X-ray source and detector. The detector detects the X-rays transmitted through the patient. The detection data is transmitted from the rotating section to a stationary section that holds the rotating section in a rotatable position, where image processing, such as reconstruction, is performed by a control console connected to the stationary section.

[0003] In order to transmit detection data from the rotating part to the stationary part, a non-contact data transmission device is used (for example, see Patent Document 1). As a non-contact transmission method, capacitive coupling using capacitive coupling and optical transmission using light are known.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-244148

[0005] In recent years, the data capacity transmitted from the rotating section to the stationary section has tended to increase. For example, in PCCT (Photon Counting Computed Tomography) devices that use photon counting detectors that count photons of incident X-rays, a large amount of data needs to be transmitted from the rotating section to the stationary section at high speed due to the large amount of data being detected.

[0006] In CT scanners using capacitively coupled data transmission devices, a transmitting antenna is provided in the rotating section and a receiving antenna is provided in the stationary section. In this case, it is necessary to configure the transmitting and receiving antennas to reliably capacitively couple. For example, the transmitting antenna is configured to extend along the outer or inner periphery of the rotating section, and the receiving antenna is configured to be opposite a portion of the transmitting antenna.

[0007] In capacitive coupling, the transmission bandwidth is proportional to the coupling capacity of the transmitting and receiving antennas. The coupling capacitance depends on the distance between the transmitting and receiving antennas and the area of ​​their overlap. For stable data transmission in capacitive coupling, the positional relationship between the transmitting and receiving antennas must be maintained constant while the rotating part is rotating.

[0008] However, the rotating part may sometimes deform due to deterioration over time. If the rotating part deforms, the relative relationship between the transmitting and receiving antennas changes as the rotating part rotates, thereby changing the coupling capacitance and reducing the stability of data transmission. In particular, deformation of the rotating part has a significant impact when the distance between the transmitting and receiving antennas is reduced to improve transmission speed.

[0009] For example, to improve data transmission stability, one could measure the distance between the transmitting and receiving antennas and adjust the position of the receiving antenna based on the measurement. However, measuring this distance while the rotating part is rotating and then adjusting the receiving antenna accordingly is not easy. For instance, one could consider the possibility that the receiving antenna's displacement would take time to keep up with the rotation of the rotating part, thus reducing data transmission stability. Summary of the Invention

[0010] Therefore, the objective of the present invention is to provide a CT device and a control method for the CT device that can improve the stability of data transmission based on capacitive coupling.

[0011] The CT apparatus of the present invention comprises: an X-ray source for emitting X-rays onto a subject; a detector for detecting the X-rays transmitted through the subject and outputting detection data; a rotating unit for supporting the X-ray source and the detector and rotating about a rotation axis; a stationary unit for holding the rotating unit in a rotatable position; a transmitting antenna disposed on the rotating unit for transmitting detection data; a receiving antenna disposed at a position opposite to a portion of the transmitting antenna; a rotation position detection unit for detecting the rotation position of the rotating unit and outputting a detection value; a measuring unit for measuring the relative relationship between the transmitting antenna and the receiving antenna and outputting a measurement value; a displacement mechanism for displacing at least one of the receiving antenna and the transmitting antenna; and a processor for creating control data based on the detection value and the measurement value, and controlling the displacement mechanism based on the control data during the transmission and reception of detection data, thereby performing displacement control to suppress changes in the relative relationship.

[0012] The preferred processor performs the following processing: based on the detected and measured values ​​of one cycle of rotation of the rotating part, it creates relative relationship data representing the relationship between the relative relationship of one cycle and the rotation position, and creates control data based on the relative relationship data.

[0013] The preferred control data represents the relationship between the displacement and rotational position of at least one of the receiving and transmitting antennas for one cycle.

[0014] Preferably, the transmitting antenna is configured along the outer or inner periphery of the rotating part.

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

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

[0017] The relative relationship can be the overlap ratio of the transmitting antenna and the receiving antenna, and the displacement mechanism can make the receiving antenna displace around an axis parallel to the direction orthogonal to the rotation axis.

[0018] Preferably, it has a receiver that receives detection data via a receiving antenna.

[0019] The displacement mechanism moves the receiving antenna by moving the receiver.

[0020] The processor can correct the control data based on the measured values ​​during the execution of displacement control.

[0021] The processor can correct the control data based on the difference between the measured value one cycle ago, a certain time ago, or a certain rotation angle ago and the acquired measured value.

[0022] The control method for a CT apparatus according to the present invention comprises: an X-ray source that radiates X-rays onto a subject; a detector that detects the X-rays transmitted through the subject and outputs detection data; a rotating unit that supports the X-ray source and the detector and rotates about a rotation axis; a stationary unit that holds the rotating unit in a position capable of rotation; a transmitting antenna disposed on the rotating unit for transmitting detection data; a receiving antenna disposed at a position opposite to a portion of the transmitting antenna; a rotation position detection unit that detects the rotation position of the rotating unit and outputs a detection value; a measuring 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 this control method, a processor creates control data based on the detection value and the measurement value, and controls the displacement mechanism based on the control data during the transmission and reception of the detection data, thereby performing displacement control to suppress changes in the relative relationship.

[0023] Invention Effects

[0024] According to the technology of the present invention, a CT device and a control method for the CT device can be provided that can improve the stability of data transmission based on capacitive coupling. Attached Figure Description

[0025] Figure 1 It is a diagram that roughly represents the structure of a CT scanner.

[0026] Figure 2 It is a diagram that roughly represents the structure of the frame.

[0027] Figure 3 This is a diagram showing the structure of a data transmission device.

[0028] Figure 4 This is a diagram that roughly illustrates the structure of the transmitting and receiving antennas.

[0029] Figure 5 This is a diagram that roughly illustrates the structure of the transmitting and receiving antennas.

[0030] Figure 6 This is a diagram showing an example of the structure of the displacement control unit.

[0031] Figure 7 This is a diagram illustrating an example of the process of controlling data creation and processing.

[0032] Figure 8 This is a diagram representing an example of relative relational data.

[0033] Figure 9 This is a diagram representing an example of control data.

[0034] Figure 10 This is a diagram illustrating an example of the displacement control process.

[0035] Figure 11 This is a diagram showing the structure of the measuring unit and displacement mechanism involved in the first modified example.

[0036] Figure 12 This is a diagram illustrating parallelism.

[0037] Figure 13 This is a graph illustrating the overlap rate.

[0038] Figure 14 This is a diagram illustrating an example of the displacement control process involved in the second variation.

[0039] Figure 15 This is a diagram that roughly illustrates the structural example of the transmitting antenna and receiving antenna involved in the third variation.

[0040] Symbol Explanation

[0041] 1-CT apparatus, 2-gantry, 2A-opening, 2B-rotating section, 2C-stationary section, 2D-outer peripheral section, 2E-inner peripheral section, 3-bed, 3A-sit plate, 3B-base, 3C-drive section, 4-control console, 5-data transmission device, 6-high voltage generating section, 7-aperture drive section, 8-gantry drive section, 10-X-ray source, 11-X-ray tube, 12-aperture, 20-detector, 21-data collection section, 40-processor, 41-display, 42-input device, 50-first memory, 51-transmitter, 52-transmission device 53-Receiving antenna, 54-Receiver, 54a-Surface, 55-Second memory, 56-Transmission control unit, 60-Rotation position detection unit, 61-Measuring unit, 61A-First measuring unit, 61B-Second measuring unit, 61C-Third measuring unit, 62-Displacement mechanism, 62A-First displacement mechanism, 62B-Second displacement mechanism, 62C-Third displacement mechanism, 63-Displacement control unit, 63A-Processor, 63B-Storage device, 63C-Memory, 64-Program, 65-Control data, C-Rotation axis, H-Subject. Detailed Implementation

[0042] Figure 1 The structure of the CT apparatus 1 is shown in general. The CT apparatus 1 consists of a gantry 2, a bed 3, and a control console 4. In addition, the CT apparatus 1 is not limited to a CT apparatus with a charge integrating detector, but may also be a PCCT apparatus with a photon counting detector that counts the photons of the incident X-rays.

[0043] The frame 2 has a central opening 2A through which a portion of the bed 3 is inserted. Inside the frame 2 are an X-ray source 10 that emits X-rays to the subject H and a detector 20 that detects the X-rays transmitted through the subject H to generate a radiographic image. The X-ray source 10 and the detector 20 are configured to rotate along the annular shape of the frame 2 while maintaining their opposing positional relationship.

[0044] The bed 3 has a reclining plate 3A for placing the subject H, a base 3B for supporting the reclining plate 3A, and a drive unit 3C for reciprocating the reclining plate 3A in the direction of arrow A, and is configured to move the subject H. The reclining plate 3A can slide relative to the base 3B in the direction of arrow A via the drive unit 3C. When photographing the subject H, the reclining plate 3A is slid and inserted into the opening 2A of the frame 2. Thus, the subject H is transported into the opening 2A.

[0045] The console 4 is a computer consisting of a processor 40, such as a CPU (Central Processing Unit), a display 41, such as an LCD, and input devices 42, such as a keyboard and mouse.

[0046] Figure 2 The structure of the gantry 2 is shown in general. The gantry 2 is a device for irradiating a subject H with X-rays and collecting detection data of the X-rays transmitted through the subject H. The gantry 2 has a rotating part 2B and a stationary part 2C. A data transmission device 5 is provided between the rotating part 2B and the stationary part 2C for transmitting data from the rotating part 2B to the stationary part 2C in a non-contact manner.

[0047] The rotating part 2B supports the X-ray source 10, the detector 20, and the data collection part 21. The rotating part 2B is a disk-shaped rotating body that supports the X-ray source 10 and the detector 20 in a state of mutual opposition and can rotate about the rotation axis C. The aforementioned opening 2A is formed in the center of the rotating part 2B. The data collection part 21 is mounted on the detector 20. The rotating part 2B rotates on a circular track centered on the rotation axis C. The subject H is arranged with its body axis approximately aligned with the rotation axis C.

[0048] 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 subject H with the generated X-rays. The aperture 12 shapes the X-rays generated by the X-ray tube 11 into a cone-shaped beam with a specified fan angle and cone angle.

[0049] The detector 20 is configured to include multiple X-ray detection elements. The detector 20 uses these multiple X-ray detection elements to detect data (hereinafter referred to as "detection data") representing the intensity distribution of X-rays transmitted through the subject H, and outputs this detection data. For example, the detector 20 is a two-dimensional X-ray detector with multiple X-ray detection elements arranged in two mutually orthogonal directions (i.e., the slicing direction and the channel direction). The detector 20 is capable of capturing a three-dimensional imaging region with width in the slicing direction through a single rotational scan. Furthermore, the slicing direction is parallel to the rotation axis C, and the channel direction is a rotational direction centered on the rotation axis C.

[0050] The data collection unit 21 is a DAS (Data Acquisition System) that collects the detection data output from the detector 20. Furthermore, the data collection unit 21 converts the collected detection data into digital data and sends it to the data transmission device 5.

[0051] The stationary part 2C is a holding member that keeps the rotating part 2B in a rotatable state. The stationary part 2C includes a high voltage generating part 6, an aperture driving part 7, and a frame driving part 8.

[0052] The high-voltage generating unit 6 causes the X-ray tube 11 to generate X-rays by applying a high voltage to the X-ray tube 11. The aperture driving unit 7 drives the aperture 12 to make the X-rays generated by the X-ray tube 11 form a predetermined shape. The frame driving unit 8 drives the rotating unit 2B to rotate.

[0053] The high-voltage generating unit 6, the aperture driving unit 7, and the frame driving unit 8 are controlled by the control console 4. Furthermore, the control console 4 controls the driving unit 3C of the bed 3.

[0054] Figure 3 The structure of the data transmission device 5 is shown. The data transmission device 5 includes 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 located in the rotating part 2B. The receiving antenna 53, the receiver 54, the second memory 55, and the transmission control unit 56 are located in the stationary part 2C.

[0055] 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 the transmitting antenna 52. Specifically, the transmitter 51 generates a high-frequency electrical signal by modulating the amplitude, phase, frequency, etc. of the carrier wave according to the detection data and supplies it to the transmitting antenna 52. The transmitting antenna 52 transmits the electrical signal supplied by the transmitter 51 as a radio wave.

[0056] Receiver 54 is a receiving circuit that receives detection data transmitted from transmitter 51 via transmitting antenna 52 via receiving antenna 53 and stores it in the second memory 55. Specifically, receiving antenna 53 detects radio waves emitted from transmitting antenna 52 and generates an electrical signal, which is then supplied to receiver 54. Receiver 54 demodulates the electrical signal supplied from receiving antenna 53 to convert it into detection data and stores it in the second memory 55.

[0057] The transmission control unit 56 transmits and receives detection data (hereinafter also referred to as data transmission) by controlling the first memory 50, transmitter 51, transmitting antenna 52, receiving antenna 53, receiver 54, and second memory 55 respectively. Furthermore, the transmission control unit 56 transmits detection data from the second memory 55 to the control console 4.

[0058] Furthermore, the data transmission device 5 includes a rotational position detection unit 60, a measuring 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 part 2B, and the measuring unit 61, the displacement mechanism 62, and the displacement control unit 63 are provided in the stationary part 2C.

[0059] 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 the rotation angle from a reference angle. The detected value of the rotational position by the rotational position detection unit 60 is transmitted to the displacement control unit 63 via wired or wireless means.

[0060] The measuring unit 61 is a measuring sensor that measures the relative relationship between the transmitting antenna 52 and the receiving antenna 53 and supplies the measured value to the displacement control unit 63. In this embodiment, the measuring unit 61 measures the distance L (reference distance) between the transmitting antenna 52 and the receiving antenna 53. Figure 4 For example, the measuring unit 61 is a laser displacement meter, fixed near the receiving antenna 53. The measuring 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.

[0061] The measuring unit 61 only needs to be able to measure the relative relationship between the transmitting antenna 52 and the receiving antenna 53, and can be constructed from optical devices such as a dial gauge or a camera. Furthermore, the measuring unit 61 can also be a gyroscope sensor installed inside the rotating unit 2B. Moreover, the distance L between the transmitting antenna 52 and the receiving antenna 53 can be measured based on the detection intensity of the radio waves emitted from the transmitting antenna 52 by the receiving antenna 53.

[0062] The displacement mechanism 62 is a mechanism for changing 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 the receiving antenna 53 is displaced relative to the transmitting antenna 52 by displacing the receiver 54. In this invention, displacement includes not only translational movement of the object, but also rotational movement.

[0063] In this embodiment, the displacement mechanism 62 displaces (i.e., translates) the receiving antenna 53, thereby changing the distance L between the transmitting antenna 52 and the receiving antenna 53. For example, the displacement mechanism 62 is an actuator including a piezoelectric motor, a stepper motor, a servo motor, etc.

[0064] The displacement control unit 63 controls the displacement mechanism 62 while the rotating part 2B is rotating 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 move the receiving antenna 53 radially ( Figure 3 The displacement in the Z direction (as shown) suppresses the change in the distance L between the transmitting antenna 52 and the receiving antenna 53 during rotation.

[0065] Furthermore, before performing displacement control, the displacement control unit 63 acquires the detected value of the rotational position by the rotational position detection unit 60 and the measured value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 by the measuring unit 61 while the rotating unit 2B is rotating. Based on the data representing the relationship between the acquired rotational position and the relative relationship, the displacement control unit 63 creates control data to eliminate changes in the relative relationship between the transmitting antenna 52 and the receiving antenna 53. Then, the displacement control unit 63 uses the created control data to perform displacement control.

[0066] Figure 4 The following is a schematic representation of the structure 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 portion 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 patterned shape such as a ring, an arc, or a zigzag shape arranged along the outer periphery 2D centered on the rotation axis C. The outer periphery 2D refers to the outer part of the rotating portion 2B. In this embodiment, the outer periphery 2D is the outer peripheral surface centered on the rotation axis C, and the transmitting antenna 52 is exposed on the outer peripheral surface.

[0067] The receiving antenna 53 is positioned opposite a portion of the transmitting antenna 52, which is arranged along the outer periphery 2D of the rotating portion 2B. Furthermore, the receiving antenna 53 is composed of a conductive component disposed on the surface 54A of the receiver 54. Figure 5 As shown, the receiving antenna 53 is part of the receiving circuit (not shown) and has a straight line, arc, zigzag, or other patterned shape that is opposite to and parallel to a part of the transmitting antenna 52.

[0068] exist Figure 4 and Figure 5 In this configuration, the direction parallel to the rotation axis C is defined as the Y direction; the direction orthogonal to the Y direction, in which the transmitting antenna 52 and the receiving antenna 53 are positioned opposite each other, is defined as the Z direction; and the direction orthogonal to both the Y and Z directions is defined as the X direction. The receiving antenna 53 is parallel to the X direction. Furthermore, the tangent line in the portion of the transmitting antenna 52 opposite the receiving antenna 53, in the direction orthogonal to the rotation axis C, is approximately parallel to the X direction.

[0069] Figure 6 This illustrates a structural example of the displacement control unit 63. The displacement control unit 63 includes a processor 63A (such as a CPU, Central Processing Unit), a non-volatile storage device 63B, and a memory 63C serving as a temporary storage area. The non-volatile storage device 63B stores a program 64 and control data 65.

[0070] The displacement control unit 63 performs control data creation processing for creating control data 65 and the aforementioned displacement control by executing processing according to the program 64 read from the processor 63A into the memory 63C.

[0071] Figure 7 This illustrates an example of the control data creation process. In the control data creation process, firstly, the displacement control unit 63 rotates the rotation unit 2B via the control console 4 (step S10). Next, the displacement control unit 63 obtains the detected value of the rotation position from the rotation position detection unit 60 (step S11). Furthermore, the displacement control unit 63 obtains the measured value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 from the measuring unit 61 (step S12).

[0072] Alternatively, steps S11 and S12 can be executed in parallel.

[0073] Next, the displacement control unit 63 determines whether the rotation of the rotating unit 2B has completed one cycle (step S13). If the rotation of the rotating unit 2B has not completed one cycle (step S13: no), the displacement control unit 63 returns to step S11. That is, the displacement control unit 63 executes steps S11 and S12 at predetermined time intervals during the period until the rotation of the rotating unit 2B has completed one cycle.

[0074] When the rotation of the rotating unit 2B has completed one cycle (step S13: Yes), the displacement control unit 63 creates relative relationship data representing the relationship between the relative relationship of one cycle and the rotation position based on the detected value of the rotation position and the measured value of the relative relationship for one cycle (step S14). Then, the displacement control unit 63 creates control data 65 for eliminating changes in the relative relationship based on the relative relationship data (step S15), and records the created control data 65 in the storage device 63B (step S16). At this point, the control data creation process is complete.

[0075] In addition, the displacement control unit 63 can also create relative relationship data by averaging the data of the detected values ​​of rotational positions and the measured values ​​of relative relationships over two or more cycles.

[0076] Furthermore, it is preferable that the displacement control unit 63 performs control data creation processing when the subject H is not positioned on the bed 3. For example, the displacement control unit 63 can perform control data creation processing during the warm-up period after the CT device 1 is started, or during imaging preparation. Alternatively, control data creation processing can also be performed when the subject H is positioned on the bed 3. For example, the displacement control unit 63 can perform control data creation processing at more than one time during the imaging of the subject H by the CT device 1.

[0077] Figure 8An example of data representing relative relationships. Figure 8 The relative data shown represents 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 at which data transmission becomes stable. Because the rotating part 2B deforms due to time-related deterioration, the distance L between the transmitting antenna 52 and the receiving antenna 53 changes relative to the ideal distance L0.

[0078] Figure 9 This represents an example of control data 65. Figure 9 The control data 65 shown represents the relationship between the displacement D of the receiving antenna 53, which is displaced by the displacement mechanism 62, and its rotational position. The displacement D is the amount of drive required in the Z direction of the receiving antenna 53 to suppress changes in the distance L between the transmitting antenna 52 and the receiving antenna 53 and to set this distance L to the ideal distance L0.

[0079] Figure 10 This illustrates an example of a displacement control process. In displacement control, firstly, the displacement control unit 63 reads control data 65 from the storage device 63B into the memory 63C (step S20). Next, the displacement control unit 63 determines whether the transmission of detection data has started by the data transmission device 5 (step S21). If data transmission has not started (step S21: No), the displacement control unit 63 repeatedly performs this determination.

[0080] When data transmission has started (step S21: Yes), the displacement control unit 63 obtains the detected value of the rotational position from the rotational position detection unit 60 (step S22). Furthermore, the displacement control unit 63 calculates 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).

[0081] 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 to step S22. That is, the displacement control unit 63 executes steps S22 and S23 at predetermined time intervals during the period until the data transmission ends. If the data transmission has ended (step S24: Yes), the displacement control unit 63 terminates the displacement control.

[0082] As described above, in this embodiment, the receiving antenna 53 is displaced according to pre-created control data 65 to suppress changes in the distance L between the transmitting antenna 52 and the receiving antenna 53, thus stabilizing the coupling capacitance between the transmitting antenna 52 and the receiving antenna 53. In this embodiment, since pre-created control data 65 is used, there is no need to perform calculations to determine the displacement D during rotation, improving the tracking accuracy of the receiving antenna 53's displacement relative to the rotation of the rotating part 2B. Therefore, according to this embodiment, the stability of data transmission based on capacitive coupling can be improved.

[0083] The following describes various variations of the above-described embodiments.

[0084] [First Variation]

[0085] 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 can also measure relative relationships other than the distance L. Furthermore, in the above embodiment, the displacement mechanism 62 displaces the receiving antenna 53 radially (i.e., in the Z direction) along the rotating part 2B, but it can also displace it in a direction other than the Z direction.

[0086] Figure 11 This section illustrates the structure of the measuring unit 61 and the displacement mechanism 62 involved in the first modification. In this modification, the measuring unit 61 is configured to include a first measuring unit 61A, a second measuring unit 61B, and a third measuring unit 61C. Furthermore, the displacement mechanism 62 is configured to include a first displacement mechanism 62A, a second displacement mechanism 62B, and a third displacement mechanism 62C.

[0087] The first measuring unit 61A has the same structure as the measuring unit 61 in the above embodiment, and measures the distance L between the transmitting antenna 52 and the receiving antenna 53.

[0088] The second measuring unit 61B measures the parallelism between the transmitting antenna 52 and the receiving antenna 53. For example... Figure 12 As shown, the portion of the transmitting antenna 52 opposite the receiving antenna 53 is approximately flat. Specifically, the tilt angle α of the transmitting antenna 52 at the portion opposite the receiving antenna 53 is measured. The tilt angle α is the angle about an axis parallel to the Y direction. The smaller the tilt angle α, the higher the parallelism and the more stable the data transmission.

[0089] For example, the second measuring unit 61B is a plurality of laser displacement gauges disposed in the X direction. The second measuring unit 61B measures the tilt angle α by measuring the distance between the transmitting antenna 52 and the receiving antenna 53 at multiple positions in the X direction. Alternatively, the second measuring unit 61B can also be a camera that captures images of the transmitting antenna 52 and the receiving antenna 53 from the Y direction, and measures the tilt angle α based on the captured images.

[0090] The third measurement unit 61C measures the overlap rate between the transmitting antenna 52 and the receiving antenna 53. For example... Figure 13 As shown, when viewed from the Z direction, the transmitting antenna 52 and the receiving antenna 53 approximately overlap. However, if the transmitting antenna 52 is tilted in the XY plane, the overlap rate decreases. The third measuring unit 61C measures the tilt angle β of the portion of the transmitting antenna 52 opposite to the receiving antenna 53 relative to the transmitting antenna 52. The tilt angle β is the angle about 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.

[0091] For example, the third measurement unit 61C is a camera that captures images of the transmitting antenna 52 from the Z direction. The third measurement unit 61C measures the tilt angle β based on the captured image.

[0092] The first displacement mechanism 62A has the same structure as the displacement mechanism 62 in the above embodiment, which causes the receiving antenna 53 to be displaced along the Z direction, so that the distance L between the transmitting antenna 52 and the receiving antenna 53 changes.

[0093] The second displacement mechanism 62B causes the receiving antenna 53 to displace (i.e., rotate) about an axis parallel to the Y-axis, thereby changing 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 the receiving antenna 53 is displaced by displacing the receiver 54.

[0094] The third displacement mechanism 62C displaces (i.e., rotates) the receiving antenna 53 about an axis parallel to the Z-axis, thereby changing 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.

[0095] In this modified example, 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 in the above embodiment, which controls the first displacement mechanism 62A based on the detected value of the rotational position detected by the rotational position detection unit 60 and the measured value measured by the first measuring unit 61A.

[0096] The second displacement control controls the displacement of the second displacement mechanism 62B based on the detected value of the rotational position detected by the rotational position detection unit 60 and the measured value measured by the second measuring unit 61B. The third displacement control controls the displacement of the third displacement mechanism 62C based on the detected value of the rotational position detected by the rotational position detection unit 60 and the measured value measured by the third measuring unit 61C.

[0097] Similar to the above embodiment, before executing the first displacement control, the second displacement control, and the third displacement control, the displacement control unit 63 creates first relative relationship data, second relative relationship data, and third relative relationship data. The first relative relationship data is the same relative relationship data as in the above embodiment, representing the relationship between the distance L between the transmitting antenna 52 and the receiving antenna 53 and the rotational position.

[0098] The second relative relationship data represents the relationship between parallelism (i.e., tilt angle α) and rotational position. The third relative relationship data represents the relationship between overlap rate (i.e., tilt angle β) and rotational position.

[0099] Furthermore, the displacement control unit 63 performs control data creation processing to create first control data, second control data, and third control data based on the first relative relationship data, the second relative relationship data, and the third relative relationship data. Similar to the above embodiment, the first control data represents the relationship between the displacement amount D of the receiving antenna 53 in the Z direction displaced by the first displacement mechanism 62A and the rotational position.

[0100] The second control data represents the relationship between the displacement (i.e., rotation) of the receiving antenna 53 about an axis parallel to the Y-axis, displaced by the second displacement mechanism 62B, and its rotational position. The third control data represents the relationship between the displacement (i.e., rotation) of the receiving antenna 53 about an axis parallel to the Z-axis, displaced by the third displacement mechanism 62C, and its rotational position.

[0101] The first control data, the second control data, and the third control data respectively represent the relationship between the rotational position and the displacement of the rotating unit 2B in one cycle. In addition, the displacement control unit 63 can also create the first relative relationship data, the second relative relationship data, and the third relative relationship data by performing averaging processing on the data of the detected values ​​of the rotational position and the measured values ​​of the relative relationship of two or more cycles.

[0102] The execution time of the control data creation process in this variation is the same as that in the above-described implementation.

[0103] Furthermore, the technology of the present invention only requires the execution of one or more of the first displacement control, the second displacement control, and the third displacement control.

[0104] [Second Variation]

[0105] In the above embodiment, the displacement control unit 63 performs displacement control based on pre-created control data 65. However, the control data 65 can also be corrected during the execution of displacement control based on the measurement values ​​measured by the measurement unit 61. After the control data 65 is created, changes in environmental conditions such as temperature, humidity, and air pressure, the rotational speed of the rotating unit 2B, the scanning time, and the years of use of the device can cause the control data 65 to deviate from its optimal value. As a result, the stability of data transmission may decrease. As in this modified example, by correcting the control data 65 based on the measurement values ​​during the execution of displacement control, the effects caused by changes in the aforementioned environmental conditions or device conditions can be suppressed, and the stability of data transmission can be improved.

[0106] Figure 14 This illustrates an example of the displacement control process involved in the second variation. The only difference between the displacement control process involved in this variation and the displacement control process involved in the above-described embodiment is that steps S30 and S31 are added between steps S22 and S23.

[0107] In this modified example, after the displacement control unit 63 obtains the detected value of the rotational position from the rotational position detection unit 60 in step S22, it obtains the measured value of the relative relationship between the transmitting antenna 52 and the receiving antenna 53 from the measuring unit 61 (step S30). Next, the displacement control unit 63 corrects the control data 65 based on the obtained measured value (step S31). Specifically, the displacement control unit 63 corrects the displacement amount corresponding to the rotational position obtained in step S22 based on the difference between the measured value one cycle ago, a certain time ago, or a certain rotational angle ago and the measured value obtained in step S30. For example, the displacement control unit 63 uses the displacement amount (i.e., the control quantity) calculated by PID (Proportional-Integral-Differential) control, moving average, feedback control, feedforward control, etc., for correction.

[0108] Then, the displacement control unit 63 controls the displacement mechanism 62 according to the displacement amount corrected in step S31 (step S23).

[0109] Alternatively, the second variation can also be applied to the first displacement control, the second displacement control, and the third displacement control described in the first variation above.

[0110] In the technology of this invention, the relative relationship between the transmitting antenna 52 and the receiving antenna 53 is set to a constant value through the above-described displacement control. This constant value includes an allowable error. This allowable error preferably varies, for example, according to the transmission frequency band 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 predetermined value with high precision, and therefore it is preferable to reduce the allowable error compared to the case of slow transmission speed.

[0111] [3rd Variation]

[0112] In the above embodiment, the transmitting antenna 52 is configured to be exposed outside the rotating part 2B, but the transmitting antenna 52 may also be configured inside the rotating part 2B.

[0113] Figure 15 The following is a simplified representation of the structure of the transmitting antenna 52 and receiving antenna 53 according to the third modification. In this modification, the transmitting antenna 52 is part of a transmitting circuit (not shown) and has a patterned shape such as a ring, an arc, or a zigzag shape arranged along an inner periphery 2E centered on the rotation axis C. The inner periphery 2E refers to the portion further inward than the outer periphery surface of the rotating portion 2B. In this modification, the inner periphery 2E is the region near the outer periphery surface centered on the rotation axis C, and the transmitting antenna 52 is not exposed from the outer periphery surface. The structure of the receiving antenna 53 is the same as in the above embodiment.

[0114] [Other variations]

[0115] In the above embodiment, the displacement mechanism 62 is configured to displace the receiving antenna 53, but it can also be configured to displace the transmitting antenna 52. Furthermore, the displacement mechanism 62 can 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 representing the relationship between the displacement of at least one of the receiving antenna 53 and the transmitting antenna 52 over one cycle and their rotational position.

[0116] Furthermore, in the above embodiment, the displacement control unit 63 is disposed within the stationary part 2C, but the displacement control unit 63 may also be disposed outside the stationary part 2C, such as within the console 4. Moreover, as the hardware structure of the displacement control unit 63, various processors as shown below can be used. As described above, among the various processors, in addition to general-purpose processors (CPUs) that execute software (programs) and function as various processing units, there are also processors such as FPGAs (Field Programmable Gate Arrays) whose circuit structure can be modified after manufacturing (PLDs), and processors such as ASICs (Application Specific Integrated Circuits) with circuit structures specifically designed for performing specific processes (dedicated circuits).

[0117] The displacement control unit 63 can be composed of one of these various processors, or it can be composed of a combination of two or more processors of the same or different types (e.g., a combination of multiple FPGAs or a combination of CPU and FPGA).

[0118] The techniques described in the following notes can be understood from the above records.

[0119] [Note 1]

[0120] A CT device comprising:

[0121] An X-ray source that emits X-rays onto the subject of examination.

[0122] The detector detects X-rays that have been transmitted through the subject and outputs detection data.

[0123] The rotating part supports the X-ray source and the detector, and rotates about the rotation axis.

[0124] The stationary part keeps the rotating part able to rotate;

[0125] A transmitting antenna, disposed on the rotating part, is used to transmit the detection data;

[0126] A receiving antenna is positioned opposite a portion of the transmitting antenna;

[0127] A rotational position detection unit detects the rotational position of the rotating part and outputs a detection value.

[0128] The measurement unit measures the relative relationship between the transmitting antenna and the receiving antenna and outputs the measurement value.

[0129] A displacement mechanism is used to displace at least one of the receiving antenna and the transmitting antenna; and

[0130] The processor creates control data based on the detected value and the measured value, and controls the displacement mechanism based on the control data during the transmission and reception of the detected data, thereby performing displacement control to suppress changes in the relative relationship.

[0131] [Note 2]

[0132] According to the CT device described in Appendix 1, wherein,

[0133] The processor performs the following processing:

[0134] Relative relationship data is created based on the detected value and the measured value of one cycle of rotation of the rotating part, representing the relationship between the relative relationship of one cycle and the rotation position, and the control data is created based on the relative relationship data.

[0135] [Note 3]

[0136] According to the CT device described in Appendix 2, wherein,

[0137] The control data represents the relationship between the displacement of at least one of the receiving antenna and the transmitting antenna over a period of time and the rotational position.

[0138] [Note 4]

[0139] The CT apparatus according to any one of appendices 1 to 3, wherein,

[0140] The transmitting antenna is configured along the outer or inner periphery of the rotating part.

[0141] [Note 5]

[0142] According to the CT device described in Appendix 4, wherein...

[0143] The relative relationship refers to the distance between the transmitting antenna and the receiving antenna.

[0144] The displacement mechanism causes the receiving antenna to move in a direction parallel to the rotation axis.

[0145] [Note 6]

[0146] According to the CT device described in Appendix 4, wherein...

[0147] The relative relationship refers to the parallelism between the transmitting antenna and the receiving antenna.

[0148] The displacement mechanism causes the receiving antenna to shift about an axis parallel to the rotation axis.

[0149] [Note 7]

[0150] According to the CT device described in Appendix 4, wherein...

[0151] The relative relationship refers to the overlap rate between the transmitting antenna and the receiving antenna.

[0152] The displacement mechanism causes the receiving antenna to displace about an axis parallel to the direction orthogonal to the rotation axis.

[0153] [Note 8]

[0154] The CT apparatus according to any one of appendices 5 to 7 includes a receiver that receives the detection data via the receiving antenna.

[0155] The displacement mechanism displaces the receiving antenna by displacing the receiver.

[0156] [Note 9]

[0157] The CT apparatus according to any one of appendices 1 to 8, wherein,

[0158] The processor corrects the control data based on the measured values ​​during the execution of the displacement control.

[0159] [Note 10]

[0160] According to the CT device described in Appendix 9, wherein...

[0161] The processor corrects the control data based on the difference between the measured value one cycle ago, a certain time ago, or a certain rotation angle ago and the acquired measured value.

Claims

1. A CT device comprising: An X-ray source that emits X-rays onto the subject of the examination. The detector detects X-rays that have been transmitted through the subject and outputs detection data. The rotating part supports the X-ray source and the detector, and rotates about the rotation axis. The stationary part keeps the rotating part able to rotate; A transmitting antenna, disposed on the rotating part, is used to transmit the detection data; A receiving antenna is positioned opposite a portion of the transmitting antenna; A rotational position detection unit detects the rotational position of the rotating part and outputs a detection value. The measurement unit measures the relative relationship between the transmitting antenna and the receiving antenna and outputs the measurement value. A displacement mechanism that displaces at least one of the receiving antenna and the transmitting antenna; and The processor creates control data based on the detected value and the measured value, and controls the displacement mechanism based on the control data during the transmission and reception of the detected data, thereby performing displacement control to suppress changes in the relative relationship.

2. The CT device according to claim 1, wherein, The processor performs the following processing: Relative relationship data is created based on the detected value and the measured value of one cycle of rotation of the rotating part, representing the relationship between the relative relationship of one cycle and the rotation position, and the control data is created based on the relative relationship data.

3. The CT device according to claim 2, wherein, The control data represents the relationship between the displacement of at least one of the receiving antenna and the transmitting antenna over a period of time and the rotational position.

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

5. The CT device according to claim 4, wherein, The relative relationship refers to the distance between the transmitting antenna and the receiving antenna. The displacement mechanism causes the receiving antenna to move in a direction parallel to the rotation axis.

6. The CT apparatus according to claim 4, wherein, The relative relationship refers to the parallelism between the transmitting antenna and the receiving antenna. The displacement mechanism causes the receiving antenna to shift about an axis parallel to the rotation axis.

7. The CT device according to claim 4, wherein, The relative relationship refers to the overlap rate between the transmitting antenna and the receiving antenna. The displacement mechanism causes the receiving antenna to displace about an axis parallel to the direction orthogonal to the rotation axis.

8. The CT apparatus according to any one of claims 5 to 7, further comprising a receiver that receives the detection data via the receiving antenna. The displacement mechanism displaces the receiving antenna by displacing the receiver.

9. The CT apparatus according to claim 1, wherein, The processor corrects the control data based on the measured values ​​during the execution of the displacement control.

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

11. A control method for a CT device, the CT device comprising: An X-ray source that emits X-rays onto the subject of the examination. The detector detects X-rays that have been transmitted through the subject and outputs detection data. The rotating part supports the X-ray source and the detector, and rotates about the rotation axis. The stationary part keeps the rotating part able to rotate; A transmitting antenna, disposed on the rotating part, is used to transmit the detection data; A receiving antenna is positioned opposite a portion of the transmitting antenna; A rotational position detection unit detects the rotational position of the rotating part and outputs a detection value. The measurement unit measures the relative relationship between the transmitting antenna and the receiving antenna and outputs the measurement value. and A displacement mechanism is used to displace at least one of the receiving antenna and the transmitting antenna in the control method. The processor creates control data based on the detected value and the measured value, and controls the displacement mechanism based on the control data during the transmission and reception of the detected data, thereby performing displacement control to suppress changes in the relative relationship.

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