X-ray CT apparatus and communication system

Abstract

To suppress deterioration in communication quality between a rotating part and a fixed part of a gantry device.SOLUTION: An X-ray CT apparatus includes a rotating part, a fixed part, a first transmission line, a first coupler, a second transmission line, and a second coupler. The rotating part rotates. The fixed part is communicably connected to the rotating part. The first transmission line is disposed on one of the fixed part and the rotating part, is divided into a plurality of segments, and transmits a first communication signal. The first coupler is disposed to face the first transmission line and receives a first communication signal from the first transmission line by electromagnetic field coupling. The second transmission line is disposed on one of the fixed art and the rotating part, is divided into a plurality of segments, and transmits a second communication signal. The second coupler receives a second communication signal from the second transmission line by electromagnetic field coupling. A timing at which the gap of the first transmission line faces the first coupler is different from a timing at which the gap of the second transmission line faces the second coupler.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to an X-ray CT apparatus and a communication system.

[0002] Conventionally, the gantry device of an X-ray CT scanner has a hollow space into which a subject is inserted. The gantry device has a rotating unit that scans the subject while rotating around the subject inserted in the hollow space. Data collected by the rotating unit is transmitted to a fixed unit.

[0003] The rotating section has a long coupler formed into a substantially circular shape by arranging two arc-shaped antennas formed into a substantially semicircular shape so as to face each other. Meanwhile, the fixed section has a short coupler that receives data transmitted from the long coupler. The short coupler is arranged to face the long coupler. Because the long coupler is formed into a substantially circular shape, the short coupler can maintain its facing position even when the long coupler is rotating. The short coupler transmits and receives data to and from the facing long coupler through electromagnetic coupling.

[0004] Here, the size of the short coupler is determined according to the data transmission frequency. Therefore, as the transmission speed increases and the transmission frequency increases, the short coupler becomes smaller. In the future, it is expected that in a long coupler formed into a substantially circular shape by arranging two arc-shaped antennas formed into a substantially semicircular shape so that the short coupler will be smaller than the gap between the two arc-shaped antennas formed into a substantially semicircular shape.

[0005] However, if the short coupler is smaller than the gap, the short coupler will not face the long coupler during the period when the short coupler faces the gap, resulting in a deterioration in communication quality between the short coupler and the long coupler. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-161314 Summary of the Invention [Problem to be solved by the invention]

[0007] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to suppress deterioration of communication quality between the rotating part and the fixed part of the gantry. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0008] An X-ray CT apparatus according to an embodiment includes a rotating unit, a fixed unit, a first transmission line, a first coupler, a second transmission line, and a second coupler. The rotating unit rotates and includes an X-ray tube, an X-ray detector that detects X-rays emitted from the X-ray tube, and a data acquisition unit that collects X-ray signals detected by the X-ray detector. The fixed unit is communicatively connected to the rotating unit. The first transmission line is disposed on one of the fixed unit and the rotating unit, is divided into multiple segments, and transmits a first communication signal. The first coupler is disposed on the other of the fixed unit and the rotating unit where the first transmission line is not disposed, facing the first transmission line, and receives the first communication signal from the first transmission line by electromagnetic coupling. The second transmission line is disposed on one of the fixed unit and the rotating unit, is divided into multiple segments, and transmits a second communication signal. The second coupler is disposed on the side of the fixed portion or the rotating portion where the second transmission line is not disposed so as to face the second transmission line, and receives the second communication signal from the second transmission line by electromagnetic coupling. The timing at which the first coupler faces the gaps provided at the division positions of the plurality of segments of the first transmission line is different from the timing at which the second coupler faces the gaps provided at the division positions of the plurality of segments of the second transmission line. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of an X-ray CT apparatus according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a communication system according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing an example of each rotation angle at which the subject is scanned. [Figure 4] FIG. 4 is a diagram showing the correspondence between a conventional short coupler and a long coupler. [Figure 5] FIG. 5 is a diagram showing an example of the correspondence relationship between the short coupler and the long coupler according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of a rotary communication unit according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing an example of the correspondence relationship between the short coupler and the long coupler according to the first modification. [Figure 8] FIG. 8 is a diagram illustrating an example of the configuration of a rotary communication unit according to the first modification. [Figure 9] FIG. 9 is a diagram showing an example of the arrangement of short couplers and long couplers according to the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an X-ray CT apparatus and a communication system according to the present embodiment will be described with reference to the drawings. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant description will be omitted as appropriate.

[0011] (First embodiment) 1 is a block diagram showing an example of the configuration of an X-ray CT apparatus 1 according to the first embodiment. As shown in FIG. 1, the X-ray CT apparatus 1 according to the first embodiment includes a gantry device 10, a bed device 30, and a console device 40.

[0012] In this embodiment, the rotation axis of the rotating frame 13 in a non-tilted state or the longitudinal direction of the tabletop 33 of the bed device 30 is defined as the Z-axis direction. The axis direction that is perpendicular to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction. The axis direction that is perpendicular to the Z-axis direction and vertical to the floor surface is defined as the Y-axis direction. For the sake of explanation, FIG. 1 depicts the gantry device 10 from multiple directions, and shows a case where the X-ray CT device 1 has one gantry device 10.

[0013] The gantry 10 includes an X-ray tube 11, an X-ray detector 12, a rotating frame 13, an X-ray high voltage device 14, a control device 15, a wedge 16, a collimator 17, a DAS (Data Acquisition System) 18, and a fixed frame 19. The DAS 18 is an example of a data acquisition unit that acquires X-ray signals detected by the X-ray detector 12.

[0014] The X-ray tube 11 is a vacuum tube having a cathode (filament) that generates thermoelectrons and an anode (target) that generates X-rays upon impact of the thermoelectrons. The X-ray tube 11 generates X-rays to be irradiated onto the subject P by irradiating thermoelectrons from the cathode to the anode when a high voltage is applied from the X-ray high voltage device 14. For example, the X-ray tube 11 may be a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermoelectrons.

[0015] The wedge 16 is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 11. Specifically, the wedge 16 is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 11 so that the X-rays irradiated from the X-ray tube 11 to the subject P have a predetermined distribution. For example, the wedge 16 is a wedge filter or a bow-tie filter, which is a filter made of processed aluminum or the like so as to have a predetermined target angle and a predetermined thickness.

[0016] The collimator 17 is a lead plate or the like for narrowing the irradiation range of the X-rays that have passed through the wedge 16, and a slit is formed by combining a plurality of lead plates or the like. The collimator 17 is also sometimes called an X-ray aperture. Although FIG. 1 shows a case where the wedge 16 is disposed between the X-ray tube 11 and the collimator 17, the collimator 17 may also be disposed between the X-ray tube 11 and the wedge 16. In this case, the wedge 16 transmits and attenuates the X-rays that are irradiated from the X-ray tube 11 and whose irradiation range has been limited by the collimator 17.

[0017] The X-ray detector 12 has a plurality of detection elements that detect X-rays. Each detection element in the X-ray detector 12 detects X-rays that have been irradiated from the X-ray tube 11 and passed through the subject P, and outputs a signal corresponding to the detected X-ray dose to the DAS 18. The X-ray detector 12 has, for example, a plurality of detection element rows in which a plurality of detection elements are arranged in a channel direction (channel direction) along an arc centered on the focal point of the X-ray tube 11. The X-ray detector 12 has, for example, a structure in which a plurality of detection element rows in which a plurality of detection elements are arranged in the channel direction are arranged in a row direction (slice direction, row direction).

[0018] For example, the X-ray detector 12 is an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The scintillator array has multiple scintillators. The scintillator has scintillator crystals that output light with a photon amount corresponding to the amount of incident X-rays. The grid is arranged on the X-ray incident side of the scintillator array and has an X-ray shielding plate that absorbs scattered X-rays. The grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The photosensor array has a function of converting the amount of light from the scintillator into an electrical signal corresponding to the amount of light, and has a photosensor such as a photodiode. The X-ray detector 12 may also be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electrical signal.

[0019] X-ray high voltage device 14 has electrical circuits such as a transformer and a rectifier, and includes a high-voltage generator that generates a high voltage to be applied to X-ray tube 11, and an X-ray control device that controls the output voltage according to the X-rays generated by X-ray tube 11. The high-voltage generator may be of a transformer type or an inverter type. X-ray high voltage device 14 may be provided on rotating frame 13 or fixed frame 19. Here, fixed frame 19 is a frame that rotatably supports rotating frame 13, and has a rotation mechanism for rotating rotating frame 13.

[0020] The DAS 18 collects X-ray signals detected by each detection element of the X-ray detector 12. For example, the DAS 18 has an amplifier that amplifies the electrical signals output from each detection element and an A / D converter that converts the electrical signals into digital signals, and generates detection data. The DAS 18 is realized by, for example, a processor. The DAS 18 is an example of a data collection device.

[0021] The rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 facing each other and rotates the X-ray tube 11 and the X-ray detector 12 using a control device 15. For example, the rotating frame 13 is an aluminum casting. Note that the rotating frame 13 can further support an X-ray high voltage device 14, a wedge 16, a collimator 17, a DAS 18, etc. in addition to the X-ray tube 11 and the X-ray detector 12. Furthermore, the rotating frame 13 can further support various components not shown in FIG. 1 .

[0022] A communication system 100 is provided on the rotating frame 13 and the fixed frame 19. The communication system 100 performs communication between the devices arranged on the rotating frame 13 side and the devices arranged on the fixed frame 19 side. The devices arranged on the rotating frame 13 side are collectively referred to as a rotating unit. The devices arranged on the fixed frame 19 side are collectively referred to as a fixed unit. For example, the rotating unit includes the X-ray tube 11, the X-ray detector 12, the DAS 18, etc. The fixed unit includes the console device 40, devices connected to the console device 40, etc. The fixed unit is connected to the rotating unit so that they can communicate with each other.

[0023] The control device 15 includes a processing circuit having a CPU (Central Processing Unit) and the like, and a driving mechanism such as a motor and an actuator. The control device 15 receives input signals from the input interface 43 and controls the operation of the gantry 10 and the bed 30. For example, the control device 15 controls the rotation of the rotating frame 13, the tilt of the gantry 10, and the operation of the bed 30 and the tabletop 33. As an example, to control the tilt of the gantry 10, the control device 15 rotates the rotating frame 13 around an axis parallel to the X-axis direction based on input inclination angle (tilt angle) information. The control device 15 may be provided in the gantry 10 or in the console device 40.

[0024] The bed device 30 is a device on which the subject P to be imaged is placed and moved, and includes a base 31, a bed driving device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so that it can move in the vertical direction. The bed driving device 32 is a drive mechanism that moves the top plate 33, on which the subject P is placed, in the longitudinal direction of the top plate 33, and includes a motor, an actuator, etc. The top plate 33, which is provided on the upper surface of the support frame 34, is a plate on which the subject P is placed. Note that the bed driving device 32 may move the support frame 34 in addition to the top plate 33 in the longitudinal direction of the top plate 33.

[0025] The console device 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as being separate from the gantry device 10, the gantry device 10 may include the console device 40 or some of the components of the console device 40.

[0026] The memory 41 is realized by, for example, a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, an optical disk, etc. The memory 41 stores, for example, projection data and CT image data. Furthermore, for example, the memory 41 stores programs that enable circuits included in the X-ray CT apparatus 1 to realize their functions. The memory 41 may also be realized by a group of servers (cloud) connected to the X-ray CT apparatus 1 via a network.

[0027] The display 42 displays various types of information. For example, the display 42 displays various images generated by the processing circuitry 44, or displays a GUI (Graphical User Interface) for receiving various operations from an operator. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 42 may be provided on the gantry device 10. The display 42 may be a desktop type, or may be configured as a tablet terminal or the like capable of wireless communication with the console device 40 main body.

[0028] The input interface 43 accepts various input operations from the operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuitry 44. For example, the input interface 43 accepts input operations from the operator, such as reconstruction conditions for reconstructing CT image data and image processing conditions for generating post-processed images from the CT image data. For example, the input interface 43 may be implemented by a mouse, keyboard, trackball, switch, button, joystick, a touchpad for performing input operations by touching the operation surface, a touchscreen integrating a display screen and a touchpad, a non-contact input circuit using an optical sensor, a voice input circuit, or the like. The input interface 43 may also be provided in the gantry 10. The input interface 43 may also be implemented by a tablet terminal or the like capable of wireless communication with the console device 40 main body. The input interface 43 is not limited to those having physical operation components such as a mouse and keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the console device 40 and outputs the electrical signal to the processing circuitry 44 is also included as an example of the input interface 43.

[0029] The processing circuitry 44 controls the overall operation of the X-ray CT apparatus 1. The processing circuitry 44 has, for example, a system control function 440, a scan control function 441, a pre-processing function 442, a reconstruction processing function 443, and a display control function 444. In the embodiment, each processing function performed by the system control function 440, the scan control function 441, the pre-processing function 442, the reconstruction processing function 443, and the display control function 444 is stored in the memory 41 in the form of a program executable by a computer. The processing circuitry 44 is a processor that realizes a function corresponding to each program by reading and executing the program from the memory 41. In other words, the processing circuitry 44 in a state in which each program has been read has each function shown in the processing circuitry 44 in FIG. 1.

[0030] 1 has been described as realizing the system control function 440, scan control function 441, preprocessing function 442, reconstruction processing function 443, and display control function 444 by a single processor, but it is also possible to combine multiple independent processors to configure the processing circuit 44 and have each processor execute a program to realize the function. Also, in FIG. 1, it has been described as realizing the program corresponding to each processing function by a single storage circuit such as memory 41, but it is also possible to have a configuration in which multiple storage circuits are distributed and the processing circuit 44 reads out the corresponding program from each storage circuit.

[0031] The term "processor" used in the above description refers to circuits such as a CPU (Central Processing Unit), a GPU (Graphical Processing Unit), an Application Specific Integrated Circuit (ASIC), a programmable logic device (e.g., a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). The processor realizes its functions by reading and executing a program stored in memory 41. Note that instead of storing a program in memory 41, the processor may be configured so that the program is directly embedded in its circuitry. In this case, the processor realizes its functions by reading and executing the program embedded in its circuitry.

[0032] The system control function 440 controls various functions of the processing circuit 44 based on input operations received from an operator via the input interface 43 .

[0033] The scan control function 441 executes a scan using X-rays on the subject P. For example, the scan control function 441 controls the scan based on an input operation received from an operator via the input interface 43. Specifically, the scan control function 441 controls the output voltage from the high-voltage generator by sending a control signal to the X-ray high-voltage device 14 based on the input operation. The scan control function 441 also controls data collection by the DAS 18 by sending a control signal to the DAS 18.

[0034] The preprocessing function 442 generates preprocessed data by performing preprocessing on the X-ray detection data transmitted from the DAS 18. Specifically, the preprocessing function 442 generates preprocessed data by performing logarithmic conversion processing and correction processing such as offset correction, sensitivity correction, and beam hardening correction. Note that the data before preprocessing (X-ray detection data) and the data after preprocessing may be collectively referred to as projection data.

[0035] The reconstruction processing function 443 generates CT image data by reconstructing the projection data generated by the preprocessing function 442 using various reconstruction methods (for example, back projection methods such as FBP (Filtered Back Projection), iterative approximation, etc.). The reconstruction processing function 443 also stores the generated CT image data in the memory 41.

[0036] The display control function 444 causes the display 42 to display various images generated by the processing circuitry 44. For example, the display control function 444 causes the display 42 to display CT image data generated by the reconstruction processing function 443.

[0037] Next, the communication system 100 included in the gantry 10 will be described.

[0038] 2 is a diagram showing an example of the configuration of a communication system 100 according to the first embodiment. The communication system 100 performs communication between a rotating unit arranged on the rotating frame 13 side and a fixed unit arranged on the fixed frame 19 side.

[0039] The communication system 100 has a rotary communication unit 110, a signal input / output unit 120, a long coupler 130, and a signal termination unit 140 on the rotating unit side. It is arbitrary which device the rotary communication unit 110, the signal input / output unit 120, the long coupler 130, and the signal termination unit 140 are included in. All or part of the rotary communication unit 110, the signal input / output unit 120, the long coupler 130, and the signal termination unit 140 may be included in the rotating unit.

[0040] The rotary communication unit 110, the signal input / output unit 120, the long coupler 130, and the signal termination unit 140 rotate in the directions of the arrows shown in FIG.

[0041] The rotary communication unit 110 controls communication on the rotating unit side. For example, the rotary communication unit 110 converts data generated by the rotating unit into a predetermined transfer format. For example, the rotary communication unit 110 converts the data into a high-speed serial transfer format such as 8b / 10b. Then, the rotary communication unit 110 outputs the data converted into the predetermined transfer format to the signal input / output unit 120.

[0042] Furthermore, when data in a predetermined transfer format is input from signal input / output unit 120, rotary communication unit 110 decodes the data in the predetermined transfer format. Then, rotary communication unit 110 outputs the decoded data to the rotation unit.

[0043] When transmitting data to the fixed unit, the signal input / output unit 120 receives input of the data from the rotary communication unit 110. The signal input / output unit 120 also holds the input data. The signal input / output unit 120 then applies a communication signal corresponding to the data to the long coupler 130, thereby transmitting the data.

[0044] The signal input / output unit 120 may also have various equalizers, a clock recovery function, etc. The signal input / output unit 120 may also have a function to adjust the output level. The signal input / output unit 120 may also have a waveform shaping function such as emphasis.

[0045] Furthermore, when receiving data from the fixed communication unit 150, the signal input / output unit 120 acquires a communication signal from the long coupler 130. Then, the signal input / output unit 120 outputs data corresponding to the communication signal to the rotary communication unit 110.

[0046] For example, the signal input / output unit 120 is configured by a differential buffer. However, the signal input / output unit 120 may be configured by a single-ended RF (Radio Frequency) amplifier, or may be configured by a combination of a distributor, a fan-out, an attenuator, an amplifier, a switch, etc.

[0047] The long coupler 130 is formed in a substantially annular shape by opposing a first segment 131 having an arc shape formed in a substantially semicircle to a second segment 132 having an arc shape formed in a substantially semicircle. One end of the long coupler 130 is connected to the signal input / output unit 120, and the other end is connected to the signal termination unit 140.

[0048] For example, the long coupler 130 is formed of a conductive material such as a general printed circuit board material or a flexible board. The long coupler 130 is preferably formed using a differential transmission line, but may also be formed using, for example, a microstrip line, a line with a coaxial structure, or single-ended transmission.

[0049] When transmitting data from the rotating part to the fixed part, the long coupler 130 receives a communication signal from the signal input / output unit 120. When the signal is applied, the long coupler 130 generates an electric field. At this time, the long coupler 130 also generates an electric field in the short coupler 160 through electromagnetic field coupling. That is, a voltage corresponding to the time-varying communication signal is applied to the long coupler 130, causing the short coupler 160 to generate an electric field corresponding to the communication signal. In this way, the long coupler 130 transmits data from the rotating part to the fixed part.

[0050] When receiving data from the fixed part, the long coupler 130 generates an electric field due to electromagnetic field coupling in response to the communication signal applied to the short coupler 160. This allows the long coupler 130 to receive data from the fixed part.

[0051] Here, the long coupler 130 is formed in a substantially circular ring shape by a first segment 131 and a second segment 132. By dividing the long coupler 130 into the first segment 131 and the second segment 132, the time required to generate an electric field from one end to the other end of the long coupler 130 is shortened compared to when the long coupler 130 is not divided. In other words, by dividing the long coupler 130 into the first segment 131 and the second segment 132, the time required to generate an electric field from one end to the other end of the long coupler 130 can be kept within an allowable range.

[0052] The long coupler 130 has two gaps because it is formed into a substantially circular shape by opposing the first segment 131 and the second segment 132. More specifically, the long coupler 130 has a first gap 133 between the first segment 131 and the second segment 132 on the signal input / output section 120 side, and a second gap 134 between the first segment 131 and the second segment 132 on the signal termination section 140 side. The first gap 133 is the gap on the signal input / output section 120 side where the first segment 131 and the second segment 132 are closest when the first segment 131, which is formed in a substantially semicircular shape, and the second segment 132, which is also formed in a substantially semicircular shape, are opposed to each other. The second gap 134 is a gap on the signal termination portion 140 side where the first segment 131 and the second segment 132 are closest to each other when the first segment 131, which is formed in an approximately semicircular shape, and the second segment 132, which is also formed in an approximately semicircular shape, are placed opposite each other.

[0053] Two long couplers 130 are arranged side by side in the Z-axis direction. In other words, two long couplers 130 are arranged side by side in the direction of the rotation axis of the long coupler 130. That is, the long coupler 130 transmits data through two channels: 1ch, which is a first channel formed in an annular shape with a central axis in the same direction, and 2ch, which is a second channel formed in an annular shape with a central axis in the same direction. That is, the long coupler 130 is arranged on a rotating part, is divided into multiple segments, and has 1ch for transmitting a first communication signal. 1ch of the long coupler 130 is an example of a first transmission line. Also, the long coupler 130 is arranged on a rotating part, is divided into multiple segments, and has 2ch for transmitting a second communication signal. 2ch of the long coupler 130 is an example of a second transmission line.

[0054] The signal termination unit 140 is connected to the end of the long length coupler 130 opposite to the signal input / output unit 120. The signal termination unit 140 suppresses reflection of the electrical signal. For example, the signal termination unit 140 is realized by connecting a resistor that is approximately equal to the characteristic impedance of the long length coupler 130 to ground. Note that the signal termination unit 140 may be realized by connecting a resistor that is approximately equal to the differential characteristic impedance between the differential transmission lines, or may use a termination structure with a topology such as Thevenin termination, T-type, or Π-type termination.

[0055] The communication system 100 has a fixed communication unit 150 and a short coupler 160 on the fixed unit side. It is arbitrary which device the fixed communication unit 150 and the short coupler 160 are included in. All or part of the fixed communication unit 150 and the short coupler 160 may be included in the fixed unit.

[0056] The fixed communication unit 150 controls communication on the fixed unit side. When receiving data from the rotating unit, the fixed communication unit 150 converts a communication signal generated by electromagnetic coupling between the short coupler 160 and the long coupler 130 into a digital signal. Then, the fixed communication unit 150 outputs the data converted into a digital signal to the fixed unit.

[0057] When transmitting data to the rotary communication unit 110, the fixed communication unit 150 converts the data generated by the fixed unit into a predetermined transfer format. For example, the fixed communication unit 150 converts the data into a high-speed serial transfer format such as 8b / 10b. The fixed communication unit 150 also applies a communication signal corresponding to the converted data to the short coupler 160, thereby generating an electric field in the short coupler 160.

[0058] The short coupler 160 is disposed opposite the long coupler 130 in the Z-axis direction. Like the long coupler 130, the short coupler 160 has two channels: a first channel, ch1, and a second channel, ch2. That is, the short coupler 160 is disposed at the fixed portion opposite the first channel of the long coupler 130, and has the first channel that receives a communication signal from the long coupler 130 by electromagnetic coupling. The first channel of the short coupler 160 is an example of a first coupler. The short coupler 160 is also disposed at the fixed portion opposite the second channel of the long coupler 130, and has the second channel that receives a communication signal from the long coupler 130 by electromagnetic coupling. The second channel of the short coupler 160 is an example of a second coupler.

[0059] The short coupler 160 is formed of a conductive material such as a general printed circuit board material or a flexible board. The short coupler 160 is preferably formed using a differential transmission line, but the form is not particularly limited, and it may be, for example, a microstrip line, a line with a coaxial structure, or single-ended transmission.

[0060] When the short coupler 160 receives data from the rotating part, an electric field corresponding to the communication signal applied to the long coupler 130 is generated by electromagnetic field coupling, allowing the short coupler 160 to receive data from the fixed part.

[0061] When transmitting data to the rotating part, a communication signal is applied to the short coupler 160 by the fixed communication unit 150. When the signal is applied, the short coupler 160 generates an electric field. At this time, the short coupler 160 also generates an electric field in the long coupler 130 due to electromagnetic field coupling. That is, a voltage corresponding to the time-varying communication signal is applied to the short coupler 160, causing the long coupler 130 to generate an electric field corresponding to the communication signal. In this way, the short coupler 160 transmits data to the rotating part.

[0062] Here, the circumferential length of the long coupler 130 in the short coupler 160 is determined according to the data transmission speed. For example, when transmitting at 1 Gbps (bits per second), the theoretical period per bit is 30 cm, based on the period and speed of the electrical signal. If the short coupler 160 is longer than 30 cm, there is a possibility that the value of the bit that is actually desired to be acquired and the value of the adjacent bit will become congested. Therefore, the length of the short coupler 160 is less than 30 cm. In practice, the length of the short coupler 160 is approximately half that, at 15 cm, due to the time required to transmit the electrical signal.

[0063] In recent years, there has been a demand for faster transmission between the fixed part and the rotating part. For example, when transmitting at 10 Gbps, the theoretical period per bit is 3 cm based on the period and speed of the electrical signal. Furthermore, because it takes time to transmit the electrical signal, the length of the short coupler 160 is roughly half that, at about 1.5 cm.

[0064] In this case, the length of the short coupler 160 in the circumferential direction of the long coupler 130 is shorter than the width between the first gap 133 and the second gap 134. While the short coupler 160 faces the first gap 133 or the second gap 134, the short coupler 160 is no longer facing the long coupler 130, which deteriorates communication quality. For example, while the short coupler 160 faces the first gap 133 or the second gap 134, there is an increased possibility that an error will occur in communication between the short coupler 160 and the long coupler 130.

[0065] When an error occurs, if rotary communication unit 110 or fixed communication unit 150 retransmits the data in which the error occurred, a delay will occur.

[0066] 3 is a diagram showing an example of each rotation angle at which the subject P is scanned. The X-ray CT device 1 acquires X-ray detection data by scanning the subject P at each rotation angle indicated by each triangle in FIG. 3. The X-ray CT device 1 then generates projection data by performing preprocessing on the X-ray detection data, and generates CT image data by performing reconstruction processing on the projection data.

[0067] The fixed communication unit 150 transmits a timing signal indicating the timing to scan the subject P to the rotary communication unit 110. That is, the 1st and 2nd channels of the short coupler 160 transmit timing signals indicating the timing to scan the subject P.

[0068] Furthermore, the rotary communication unit 110 notifies the rotating unit that it has received a timing signal. The timing signal is a signal that indicates the timing to scan the subject P. Therefore, when the rotating unit receives the timing signal, it scans the subject P. In this way, the rotating unit scans the subject P at each rotation angle.

[0069] Figure 4 shows the correspondence between a conventional short coupler and a long coupler. In Figure 4, T1 indicates a timing signal transmitted from the fixed part to the rotating part. That is, the short coupler 160 transmits timing signals from both ch1 and ch2. Furthermore, A1 to A4 indicate data transmitted from the fixed part to the rotating part on ch1. Furthermore, B1 to B4 indicate data transmitted from the fixed part to the rotating part on ch2.

[0070] As shown in Figure 4, when the first or second gap of the long coupler faces the short coupler, the long coupler may receive an erroneous timing signal. If the timing signal is retransmitted in this case, the X-ray detection data will be data scanned at a rotation angle different from the original rotation angle. As a result, the image quality of the CT image data will be degraded.

[0071] Therefore, the long coupler 130 has a first gap 133 and a second gap 134 at different positions in the circumferential direction for each channel. FIG. 5 is a diagram showing an example of the correspondence between the short coupler 160 and the long coupler 130 according to the first embodiment. The arrangement shown in FIG. 5 results in the timing at which a gap provided at a division position of the multiple segments of one channel of the long coupler 130 faces the first channel of the short coupler 160, differing from the timing at which a gap provided at a division position of the multiple segments of two channels of the long coupler 130 faces the second channel of the short coupler 160. More specifically, the gap between the first channel of the long coupler 130 and the gap between the second channels of the long coupler 130 are arranged with a circumferential offset from each other. Specifically, the positions of the first gap 133 and the second gap 134 are shifted in the circumferential direction of the long coupler 130 by at least the length of the timing signal between channels 1 and 2. In other words, the first gap 133 and the second gap 134 are provided so as not to overlap in the direction of the rotation axis of the long coupler 130.

[0072] As a result, at least one of ch1 and ch2 of the long coupler 130 faces the short coupler 160. Therefore, at least one of ch1 and ch2 of the long coupler 130 can receive a timing signal. In the case of FIG. 5, ch1 of the short coupler 160 faces either the first gap 133 or the second gap 134 of ch1 of the long coupler 130, and therefore fails to transmit a timing signal. On the other hand, ch2 of the short coupler 160 does not face either the first gap 133 or the second gap 134 of ch2 of the long coupler 130, and therefore can transmit a timing signal.

[0073] 6 is a diagram showing an example of the configuration of the rotary communication unit 110 according to the first embodiment. The rotary communication unit 110 is connected to the long coupler 130 via the signal input / output unit 120. That is, the rotary communication unit 110 is connected to channel 1 of the long coupler 130 and channel 2 of the long coupler 130 via the signal input / output unit 120. The rotary communication unit 110 includes an abnormality detection unit 111 and a timing extraction unit 112 for each channel of the long coupler 130. The rotary communication unit 110 also includes an extraction determination unit 113 connected to the timing extraction unit 112 for each channel.

[0074] The abnormality detection unit 111 detects an error in the communication signal from the long coupler 130. More specifically, the abnormality detection unit 111 acquires the communication signal from the long coupler 130. The abnormality detection unit 111 determines whether or not the acquired communication signal contains an error. That is, the abnormality detection unit 111 determines whether or not the communication signal received by channel 1 of the long coupler 130 and the communication signal received by channel 2 of the long coupler 130 contain an error.

[0075] If an error is contained in the acquired communication signal, the abnormality detection unit 111 does not output the acquired communication signal to the timing extraction unit 112. On the other hand, if an error is not contained in the acquired communication signal, the abnormality detection unit 111 outputs the acquired communication signal to the timing extraction unit 112.

[0076] The timing extraction unit 112 extracts a timing signal from the communication signal acquired from the abnormality detection unit 111. In other words, the timing extraction unit 112 outputs a signal indicating whether or not the timing signal has been extracted to the extraction determination unit 113.

[0077] The extraction determination unit 113 outputs the logical sum of the signals input from each timing extraction unit 112 to the rotation unit. More specifically, when at least one of the signals input from each timing extraction unit 112 indicates that a timing signal has been extracted, the extraction determination unit 113 outputs a signal indicating that the timing signal has been received to the rotation unit. That is, the extraction determination unit 113 outputs either the communication signal received by channel 1 of the long coupler 130 or the communication signal received by channel 2 of the long coupler 130. The extraction determination unit 113 outputs the communication signal received by channel 1 of the long coupler 130 or the communication signal received by channel 2 of the long coupler 130 that does not contain an error.

[0078] With this configuration, when at least one of ch1 and ch2 of the long coupler 130 receives a timing signal, the rotary communication unit 110 can notify the rotary unit.

[0079] As described above, the X-ray CT apparatus 1 according to the first embodiment includes an X-ray tube 11, an X-ray detector 12 that detects X-rays emitted from the X-ray tube 11, a DAS 18 that collects X-ray signals detected by the X-ray detector 12, and a rotating unit that rotates. The X-ray CT apparatus 1 also includes a fixed unit that is communicatively connected to the rotating unit. The X-ray CT apparatus 1 includes a long coupler 130 that is divided into multiple segments and has multiple channels for communication between the fixed unit and the rotating unit, and a short coupler 160 that is provided for each channel of the long coupler 130 and is arranged to face the long coupler 130. The X-ray CT apparatus 1 is configured such that the timing at which the gaps between the segments of the long coupler 130 face the short couplers 160 provided for each channel of the long coupler 130 differs for each channel. This allows the X-ray CT apparatus 1 to transmit communication signals through either channel 1 or channel 2 of the long coupler 130. Therefore, the X-ray CT apparatus 1 can suppress deterioration of the communication quality between the rotating part and the fixed part of the gantry device 10.

[0080] (Variation 1) The long coupler 130 and the short coupler 160 may have three or more channels. Fig. 7 is a diagram showing an example of the correspondence between the short coupler 160 and the long coupler 130 according to Modification 1. As shown in Fig. 7, the long coupler 130 and the short coupler 160 each have n channels.

[0081] 7, the gaps of the long coupler 130 are provided at different positions in the circumferential direction for each channel. In other words, the gaps of the long coupler 130 are provided so as not to overlap in the direction of the rotation axis of the long coupler 130. For example, the gaps are provided offset in the circumferential direction of the long coupler 130 by at least the length of the timing signal. This allows the long coupler 130 to receive the timing signal on another channel even if it fails to receive the timing signal on one channel.

[0082] For example, the long coupler 130 may be disposed on the rotating section, divided into multiple segments, and have three channels for transmitting a third communication signal. The three channels of the long coupler 130 are an example of a third transmission line. The short coupler 160 may be disposed on the fixed section so as to face the three channels of the long coupler 130, and have three channels for receiving a communication signal from the long coupler 130 by electromagnetic coupling. The three channels of the short coupler 160 are an example of a third coupler. As a result, the timing at which a gap formed at a division position of the multiple segments of one channel of the long coupler 130 faces the one channel of the short coupler 160 is different from the timing at which a gap formed at a division position of the multiple segments of two channels of the long coupler 130 faces the two channels of the short coupler 160, and the timing at which a gap formed at a division position of the multiple segments of three channels of the long coupler 130 faces the three channels of the short coupler 160. That is, the gap of the long coupler 130 is formed so that it faces the short coupler 160 at different timings for each channel.

[0083] Fig. 8 is a diagram showing an example of the configuration of a rotary communication unit 110a according to Modification 1. As shown in Fig. 8, the rotary communication unit 110 has an abnormality detection unit 111 and a timing extraction unit 112 for each channel of the long coupler 130. The rotary communication unit 110 also has an extraction determination unit 113a connected to the timing extraction unit 112 for each channel. With this configuration, when the rotary communication unit 110 receives a timing signal from at least one of the three or more channels of the long coupler 130, it can notify each unit related to the scan of the subject P.

[0084] (Variation 2) The first gap 133 and the second gap 134 of the long coupler 130 according to the first embodiment are provided so as to be offset in the circumferential direction of the long coupler 130. The short coupler 160 according to the second modification example is provided so as to be offset in the circumferential direction of the long coupler 130.

[0085] 9 is a diagram showing an example of the arrangement of the short coupler 160 and the long coupler 130 according to Modification 2. As shown in FIG. 9, channel 1 of the short coupler 160 and channel 2 of the short coupler 160 are arranged with a shift in the circumferential direction of the long coupler 130. More specifically, the short couplers 160 of each channel are arranged with a shift in the circumferential direction of the long coupler 130 by at least the length of the timing signal. In other words, the short couplers 160 of each channel are arranged so as not to overlap in the direction of the rotation axis of the long coupler 130. In this case, channel 1 or channel 2 of the long coupler 130 faces channel 1 or channel 2 of the short coupler 160, and therefore can receive the timing signal.

[0086] (Variation 3) Even when the short couplers 160 of each channel are shifted in the circumferential direction of the long coupler 130 as in the second modification, the long couplers 130 and short couplers 160 may have three or more channels, as in the first modification.

[0087] (Variation 4) The X-ray CT device 1 may be a PC (Photon Counting) CT device that performs imaging by counting the number of X-ray photons. In the case of a PCCT device, the DAS 18 counts the number of X-ray photons incident on each X-ray detection element using a signal output from the X-ray detector 12. More specifically, the DAS 18 allocates the calculated energy values ​​to a plurality of energy discrimination ranges (energy bins) using a comparator. The DAS 18 then counts the number of pulses allocated to each energy discrimination range as the number of X-ray photons. Each channel of the long coupler 130 and the short coupler 160 may transmit data of the corresponding energy bin. Furthermore, the timing signal may include information indicating the number of views, which indicates how many scans are performed.

[0088] (Variation 5) 2 is provided in the rotating section, and the short coupler 160 is provided in the fixed section. However, the long coupler 130 may be provided in the fixed section, and the short coupler 160 may be provided in the rotating section.

[0089] (Variation 6) In the above-described embodiment and modified examples, the communication signal is explained as a timing signal indicating the timing of scanning the subject P, but it may be any signal communicated between the fixed unit and the rotating unit. The communication signal may be, for example, a signal including at least one of a timing signal, a signal including status information, a signal including error information, and image data.

[0090] The status information is, for example, information indicating the status of a unit provided in the fixed part, and is transmitted from the fixed part to the rotating part. Here, the unit provided in the fixed part is, for example, a device in which system software that controls all or part of the fixed part is installed. Note that the unit provided in the fixed part may be any device provided that it is provided in the fixed part. Also, the status information is, for example, information indicating the status of a unit provided in the rotating part, and may be transmitted from the rotating part to the fixed part. Here, the unit provided in the rotating part is, for example, X-ray tube 11 that generates X-rays. Note that the unit provided in the rotating part may be any device provided that it is provided in the rotating part. Also, the status information may be transmitted, for example, from the rotating part to a device provided in the fixed part in which system software is installed.

[0091] The error information is information indicating that a serious error has occurred in, for example, a unit provided in the fixed part or a unit provided in the rotating part, which requires the X-ray exposure to be stopped. For example, error information regarding a unit provided in the rotating part is immediately transmitted from the rotating part to the fixed part. Based on the error information transmitted from the rotating part, the scan control function 441 generates a signal to urgently stop the generation of X-rays by the X-ray tube 11. Then, the scan control function 441 transmits a signal to the X-ray tube 11 to urgently stop the generation of X-rays by the X-ray tube 11. In this way, the scan control function 441 can immediately stop the generation of X-rays when a serious error occurs.

[0092] The image data is, for example, X-ray detection data collected by the DAS 18. The image data is then transmitted from the rotating part to the fixed part.

[0093] According to at least one of the embodiments described above, deterioration of the communication quality between the rotating part and the fixed part of the gantry device 10 can be suppressed.

[0094] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0095] 1 X-ray CT device 11 X-ray tube 12 X-ray detector 13 Rotating Frame 18 DAS(Data Acquisition System) 19 Fixed Frame 30 Bed Device 40 Console device 100 Communication Systems 110, 110a Rotating communication unit 111 Abnormality detection unit 112 Timing Extraction Unit 113, 113a Extraction judgment part 120 Signal input / output section 130 Long Coupler 140 Signal Termination Unit 150 Fixed Communications Department 131 First Segment 132 Second Segment 160 Short Coupler 133 First Gap 134 Second Gap

Claims

1. a rotating unit that has an X-ray tube, an X-ray detector that detects X-rays irradiated from the X-ray tube, and a data acquisition unit that collects X-ray signals detected by the X-ray detector, and that rotates; a fixed part communicably connected to the rotating part; a first transmission line that is arranged on one of the fixed portion and the rotating portion, that is divided into a plurality of segments, and that transmits a first communication signal; a first coupler that is disposed on one of the fixed portion and the rotating portion on which the first transmission line is not disposed so as to face the first transmission line and that receives the first communication signal from the first transmission line by electromagnetic coupling; a second transmission line that is arranged on one of the fixed portion and the rotating portion, that is divided into a plurality of segments, and that transmits a second communication signal; a second coupler that is disposed on one of the fixed portion and the rotating portion on which the second transmission line is not disposed so as to face the second transmission line and that receives the second communication signal from the second transmission line by electromagnetic coupling; Equipped with a timing at which the gaps provided at the division positions of the plurality of segments of the first transmission line and the first coupler face each other is different from a timing at which the gaps provided at the division positions of the plurality of segments of the second transmission line and the second coupler face each other. X-ray CT device.

2. the first transmission line and the second transmission line are formed in an annular shape having a central axis in the same direction, the gaps of the first transmission line and the gaps of the second transmission line are arranged so as to be shifted in a circumferential direction of the first transmission line and the second transmission line. The X-ray CT apparatus according to claim 1.

3. a third transmission line that is arranged on one of the fixed portion and the rotating portion, that is divided into a plurality of segments, and that transmits a third communication signal; a third coupler that is disposed on one of the fixed portion and the rotating portion on which the second transmission line is not disposed so as to face the third transmission line and that transmits the third communication signal from the third transmission line by electromagnetic coupling; Further provided with a timing at which the gap provided at the dividing position of the plurality of segments of the first transmission line faces the first coupler, a timing at which the gap provided at the dividing position of the plurality of segments of the second transmission line faces the second coupler, and a timing at which the gap provided at the dividing position of the plurality of segments of the third transmission line faces the third coupler are different from each other; The X-ray CT apparatus according to claim 1.

4. the first transmission line and the second transmission line are formed in an annular shape having a central axis in the same direction, the first coupler and the second coupler are arranged so as to be shifted in a circumferential direction of the first transmission line and the second transmission line; The X-ray CT apparatus according to claim 1.

5. a communication unit connected to the first transmission line and the second transmission line, the communication unit outputs either the first communication signal received via the first transmission line or the first communication signal received via the second transmission line. The X-ray CT apparatus according to claim 1.

6. the communication unit determines whether or not an error is included in the first communication signal and the second communication signal; the communication unit outputs one of the first communication signal and the second communication signal that does not include the error. The X-ray CT apparatus according to claim 5.

7. the first coupler transmits the first communication signal indicating a timing to scan the subject; the second coupler transmits the second communication signal indicating a timing to scan the subject; the communication unit determines whether or not an error is included in the first communication signal and the second communication signal; the communication unit outputs the first communication signal and the second communication signal that does not include the error to the fixed unit. The X-ray CT apparatus according to claim 6.

8. A rotating part that rotates; a fixed part communicably connected to the rotating part; a first transmission line that is arranged on one of the fixed portion and the rotating portion, that is divided into a plurality of segments, and that transmits a first communication signal; a first coupler that is disposed on one of the fixed portion and the rotating portion on which the first transmission line is not disposed so as to face the first transmission line and that receives the first communication signal from the first transmission line by electromagnetic coupling; a second transmission line that is arranged on one of the fixed portion and the rotating portion, that is divided into a plurality of segments, and that transmits a second communication signal; a second coupler that is disposed on one of the fixed portion and the rotating portion on which the second transmission line is not disposed so as to face the second transmission line and that receives the second communication signal from the second transmission line by electromagnetic coupling; Equipped with a timing at which the gaps provided at the division positions of the plurality of segments of the first transmission line and the first coupler face each other is different from a timing at which the gaps provided at the division positions of the plurality of segments of the second transmission line and the second coupler face each other. Communication system.

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