JP2022041842A - Ct cradle data radio communication system, ct cradle, and x-ray ct apparatus - Google Patents

Abstract

To provide a CT cradle data radio communication system for executing radio communication between a rotation part and a stationary part of a CT cradle that can achieve low cost and stable signal transmission, which is small in volume and can be conveniently attached.SOLUTION: A CT cradle data radio communication system includes: a first communication instrument, which is radio equipment attached to a rotation part of a CT cradle; a second communication instrument, which is radio equipment attached to a stationary part of the CT cradle; and a plurality of extension antennas which is electrically connected to one of the first communication instrument and the second communication instrument, and executes radio communication with the other. The plurality of extension antennas is attached onto a peripheral surface of the rotation part or the stationary part.SELECTED DRAWING: Figure 2

Description

The embodiments disclosed in the present specification and the drawings relate to a CT pedestal data wireless communication system, a CT pedestal, and an X-ray CT apparatus.

The X-ray CT (Computed Tomography) device has, for example, a gantry main body and a front cover that is openably and closably attached to the front surface of the gantry main body. Here, the pedestal body of the X-ray CT apparatus is described as a CT pedestal or simply a pedestal. The CT mount is also called a gantry. The CT pedestal has an annular rotating portion and a fixed portion provided in the center of the CT pedestal, an opening into which a sleeper can be inserted is provided in the central portion of the rotating portion, and an X is provided in the rotating portion. A wire tube and an X-ray detector are provided. When detecting X-rays, the X-ray detector detects the X-rays emitted from the X-ray tube and transmitted from the subject, and the X-ray CT apparatus reconstructs the image based on the detected results. Thereby, an X-ray tomographic image can be obtained.

The X-ray CT apparatus is always divided into three levels, high level, medium level, and low level, depending on the position. Here, the data transmission between the rotating part and the fixed part of the CT mount in the medium-level and low-level CT devices is realized by the optical transmission method (MUDAT), but in this case, the rotating part and the fixed part are fixed. There are problems that the number of boards required for mounting the parts is as high as several, the structure is complicated, the man-hours required for assembly are large, the accuracy required for mounting the boards is high, the occupied space is large, and the cost is high. On the other hand, the data transmission between the rotating part and the fixed part of the CT pedestal in the high-level CT device is realized by the capacity induction transmission method (SURCOM), but in this case, the occupied space is large and the cost is high. There is a problem that it is expensive.

Therefore, in the method of transmitting data between the rotating portion and the fixed portion of the CT pedestal, it is desired that the mounting is easy, the occupied space is small, and the cost is low.

For example, Patent Document 1 discloses a device that exchanges data between a rotating portion and a fixed portion of a CT mount by a wireless transmission method, and specifically, multi-input and multi-output in order to improve the bandwidth. An antenna configuration using the (MIMO) method is described. The MIMO system uses a plurality of transmitting antennas and a plurality of receiving antennas to simultaneously transmit signals on a plurality of channels. In Patent Document 1, the bandwidth is improved by providing a plurality of signal transmitting antennas and signal receiving antennas. However, when wireless communication is performed between the rotating part and the fixed part of the CT frame, the signal transmission is affected by the Doppler effect due to the relative motion of the rotating part, causing a frequency shift, and a plurality of channels are simultaneously used. When transmission is performed, some channels may have a phenomenon that the transmission rate and stability are lowered and the signal is interrupted. The frequency shift caused by the Doppler effect is also called a Doppler shift. In addition, when the gantry rotates, electromagnetic wave reflection may occur due to the presence of obstacles, or electromagnetic wave interference may occur when approaching a motor or the like.

Therefore, when wireless communication is performed between the rotating portion and the fixed portion of the CT frame, it is desired that stable signal transmission is possible.

Special Table 2009-510557 Gazette

One of the problems to be solved by the embodiments disclosed in the present specification and the drawings is that it is convenient to install in a CT pedestal data wireless communication system in which wireless communication is performed between a rotating portion and a fixed portion of the CT pedestal. The volume is small, the cost is low, and stable signal transmission is realized. However, the problems solved by the embodiments disclosed in the present specification and the drawings are not limited to the above problems. The problem corresponding to each effect by each configuration shown in the embodiment described later can be positioned as another problem.

The CT pedestal data wireless communication system according to the present embodiment is a first communication device that is a wireless device attached to a rotating portion of the CT pedestal and a second wireless device that is a wireless device attached to the fixed portion of the CT pedestal. The communication device is provided with a plurality of extended antennas that are electrically connected to one of the first communication device and the second communication device and perform wireless communication with the other, and the plurality of expansion antennas are the said. It is attached to the peripheral surface of the rotating portion or the fixed portion.

FIG. 1A is a diagram showing an example of the configuration of an X-ray CT apparatus to which the CT gantry data wireless communication system according to the first embodiment is applied. FIG. 1B is a diagram showing an example of the configuration of an X-ray CT apparatus to which the CT gantry data wireless communication system according to the first embodiment is applied. FIG. 2 is a diagram showing an example of the configuration of the CT mount data wireless communication system according to the first embodiment. FIG. 3A is a diagram showing a change in the amount of frequency deviation when an extended antenna is not used as an example of a comparative example. FIG. 3B is a diagram showing a change in the amount of frequency deviation when an extended antenna is not used as an example of a comparative example. FIG. 3C is a diagram showing a change in the amount of frequency deviation when an extended antenna is not used as an example of a comparative example. FIG. 3D is a diagram showing a change in the amount of frequency deviation when an extended antenna is not used as an example of a comparative example. FIG. 4A is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT gantry data wireless communication system according to the first embodiment. FIG. 4B is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT gantry data wireless communication system according to the first embodiment. FIG. 4C is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT gantry data wireless communication system according to the first embodiment. FIG. 4D is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT pedestal data wireless communication system according to the first embodiment. FIG. 4E is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT gantry data wireless communication system according to the first embodiment. FIG. 4F is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT pedestal data wireless communication system according to the first embodiment. FIG. 4G is a diagram showing a change in the amount of frequency deviation when an extended antenna is used in the CT pedestal data wireless communication system according to the first embodiment. FIG. 5 is a table showing a situation in which the selected extended antenna is switched according to the rotation of the CT pedestal when a plurality of extended antennas are on the fixed portion side of the CT pedestal in the CT pedestal data wireless communication system according to the first embodiment. It is a figure shown in the form of. FIG. 6A is a diagram for explaining a method of deriving a formula for calculating the number of extended antennas. FIG. 6B is a diagram for explaining a method of deriving a formula for calculating the number of extended antennas. FIG. 6C is a diagram for explaining a method of deriving a formula for calculating the number of extended antennas. FIG. 7A is a diagram for explaining the range of use of the extended antenna. FIG. 7B is a diagram for explaining the range of use of the extended antenna.

Hereinafter, embodiments of the CT pedestal data wireless communication system, the CT pedestal, and the X-ray CT apparatus will be described in detail with reference to the drawings. The CT pedestal data wireless communication system, the CT pedestal, and the X-ray CT apparatus according to the present application are not limited to the embodiments shown below.

(First Embodiment)
1A and 1B are diagrams showing an example of the configuration of an X-ray CT apparatus to which a CT pedestal data wireless communication system is applied. In FIG. 1, the X-ray CT device 1 includes a gantry device 10 (hereinafter referred to as a CT gantry 10), a sleeper device 30, and a console device 40.

Here, in FIG. 1A, the longitudinal direction of the rotation axis of the rotation frame in the non-tilt state or the top plate 33 of the sleeper device 30 is the Z-axis direction. Further, the axial direction orthogonal to the Z-axis direction and horizontal to the floor surface is defined as the X-axis direction. Further, the axial direction orthogonal to the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction. Note that FIG. 1A is a drawing of the CT pedestal 10 from a plurality of directions for the sake of explanation, and shows a case where the X-ray CT apparatus 1 has one CT pedestal 10.

As shown in FIG. 1A, the CT mount 10 includes an X-ray tube 11, an X-ray detector 12, a rotating frame 110 (hereinafter referred to as a rotating unit 110), an X-ray high voltage device 14, and a control device. It has 15, a wedge 16, a collimator 17, a DAS (Data Acquisition System) 18, and a switching circuit 19. Further, as shown in FIG. 1B, the CT mount 10 further has a fixed frame 120 (hereinafter, referred to as a fixed portion 120).

The X-ray tube 11 is a vacuum tube having a cathode (filament) that generates thermions and an anode (target) that receives the collision of thermions and generates X-rays. The X-ray tube 11 generates X-rays to irradiate the subject P by irradiating thermions from the cathode toward the anode by applying a high voltage from the X-ray high voltage device 14. For example, the X-ray tube 11 includes a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermions.

The X-ray detector 12 has a plurality of detection elements for detecting X-rays. Each detection element in the X-ray detector 12 detects X-rays 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 DAS18. The X-ray detector 12 has, for example, a plurality of detection element trains in which a plurality of detection elements are arranged in a channel direction (channel direction) along one 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 sequences in which a plurality of detection elements are arranged in the channel direction are arranged in a row direction (slice direction, row direction).

The rotating unit 110 is a rotating body that is driven to rotate. Specifically, the rotating unit 110 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 so as to face each other and rotates the X-ray tube 11 and the X-ray detector 12 by the control device 15. For example, the rotating portion 110 is a casting made of aluminum. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating unit 110 can further support the X-ray high voltage device 14, the wedge 16, the collimator 17, the DAS 18, and the like. Further, the rotating portion 110 can further support various configurations (not shown in FIGS. 1A and 1B). The central portion of the rotating portion 110 is open, and the subject P placed on the top plate of the sleeper device 30 is inserted into the opening provided in the central portion of the rotating portion 110.

The X-ray high-voltage device 14 has an electric circuit such as a transformer and a rectifier, and has a high-voltage generator that generates a high voltage applied to the X-ray tube 11 and an X-ray that is generated by the X-ray tube 11. It has an X-ray control device that controls the output voltage according to the above. The high voltage generator may be a transformer type or an inverter type. The X-ray high voltage device 14 may be provided in the rotating portion 110 or may be provided in a fixed frame (not shown).

The control device 15 has a processing circuit having a CPU (Central Processing Unit) and the like, and a drive mechanism such as a motor and an actuator. The control device 15 receives an input signal from the input interface 43 and controls the operation of the CT pedestal 10 and the sleeper device 30. For example, the control device 15 controls the rotation of the rotating portion 110, the tilt of the CT pedestal 10, the operation of the sleeper device 30, and the top plate 33, and the like. As an example, the control device 15 rotates the rotating portion 110 about an axis parallel to the X-axis direction based on the input tilt angle (tilt angle) information as a control for tilting the CT pedestal 10. The control device 15 may be provided on the CT frame 10 or the console device 40.

The wedge 16 is a filter for adjusting the X-ray dose emitted from the X-ray tube 11. Specifically, the wedge 16 transmits and attenuates the X-rays emitted from the X-ray tube 11 so that the X-rays emitted from the X-ray tube 11 to the subject P have a predetermined distribution. It is a filter to do. For example, the wedge 16 is a wedge filter or a bow-tie filter, which is a filter obtained by processing aluminum or the like so as to have a predetermined target angle and a predetermined thickness.

The collimator 17 is a lead plate or the like for narrowing the irradiation range of X-rays transmitted through the wedge 16, and a slit is formed by a combination of a plurality of lead plates or the like. The collimator 17 may be called an X-ray diaphragm. Further, in FIG. 1, a case where the wedge 16 is arranged between the X-ray tube 11 and the collimator 17 is shown, but there is a case where the collimator 17 is arranged between the X-ray tube 11 and the wedge 16. May be good. In this case, the wedge 16 is irradiated from the X-ray tube 11 and transmits and attenuates the X-ray whose irradiation range is limited by the collimator 17.

The DAS 18 collects X-ray signals detected by each detection element included in the X-ray detector 12, and generates the collected signals as data detected by the X-ray detector 12. The DAS 18 has a first communication device that transmits data detected by the X-ray detector 12 by a wireless signal, and the data detected by the X-ray detector 12 is a CT mount from the first communication device by a wireless signal. It is transferred to the fixed portion 120 which is a non-rotating portion of 10.

The fixed portion 120 is, for example, a fixed frame or the like that rotatably supports the rotating portion 110. A plurality of extended antennas 103 are arranged at equal intervals on the peripheral surface of the fixed portion 120 of the CT frame 10.

The switching circuit 19 selects and switches the extended antenna 103 to be received from the plurality of extended antennas 103. For example, the switching circuit 19 has a second communication device that receives a radio signal transmitted from the first communication device by the switched expansion antenna 103. The second communication device converts the received radio signal into a digital signal, and the data converted into the digital signal is transferred to the console device 40.

The details of the CT pedestal data wireless communication system having the first communication device, the second communication device, the plurality of extended antennas 103, and the switching circuit 19 will be described later.

The sleeper device 30 is a device for placing and moving the subject P to be imaged, and has a base 31, a sleeper drive device 32, a top plate 33, and a support frame 34. The base 31 is a housing that supports the support frame 34 so as to be movable in the vertical direction. The sleeper drive device 32 is a drive mechanism for moving the top plate 33 on which the subject P is placed in the long axis direction of the top plate 33, and includes a motor, an actuator, and the like. The top plate 33 provided on the upper surface of the support frame 34 is a plate on which the subject P is placed. In addition to the top plate 33, the sleeper drive device 32 may move the support frame 34 in the long axis direction of the top plate 33.

The console device 40 includes a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as a separate body from the CT stand 10, the CT stand 10 may include a part of each component of the console device 40 or the console device 40.

The memory 41 is realized by, for example, a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, or the like. The memory 41 stores, for example, projection data and CT image data. Further, for example, the memory 41 stores a program for the circuit included in the X-ray CT apparatus 1 to realize its function. The memory 41 may be realized by a server group (cloud) connected to the X-ray CT device 1 via a network.

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

The input interface 43 receives various input operations from the operator, converts the received input operations into electric signals, and outputs the received input operations to the processing circuit 44. For example, the input interface 43 receives from the operator input operations such as reconstruction conditions for reconstructing CT image data and image processing conditions for generating post-processed images from CT image data.

For example, the input interface 43 includes a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touch pad for performing an input operation by touching an operation surface, a touch screen in which a display screen and a touch pad are integrated, and an optical sensor. It is realized by the non-contact input circuit, voice input circuit, etc. used. The input interface 43 may be provided on the CT frame 10. Further, the input interface 43 may be composed of a tablet terminal or the like capable of wireless communication with the console device 40 main body. Further, the input interface 43 is not limited to the one provided with physical operation parts such as a mouse and a keyboard. For example, an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the console device 40 and outputs the electric signal to the processing circuit 44 is also an example of the input interface 43. included.

The processing circuit 44 controls the operation of the entire X-ray CT apparatus 1. For example, the processing circuit 44 executes the system control function 440, the scan control function 441, the preprocessing function 442, the reconstruction processing function 443, and the display control function 444.

The system control function 440 controls various functions of the processing circuit 44 based on the input operation received from the operator via the input interface 43.

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 the input operation received from the operator via the input interface 43. Specifically, the scan control function 441 controls the output voltage from the high voltage generator by transmitting a control signal to the X-ray high voltage device 14 based on the input operation. Further, the scan control function 441 controls data collection by the DAS 18 by transmitting a control signal to the DAS 18.

The pre-processing function 442 generates pre-processed data by performing pre-processing on the data transmitted from DAS 18 via the switching circuit 19. Specifically, the preprocessing function 442 generates preprocessed data by performing correction processing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction. Further, the preprocessing function 442 stores the generated data in the memory 41.

The reconstruction processing function 443 reconstructs the projection data after the preprocessing generated by the preprocessing function 442 by various reconstruction methods (for example, a back projection method such as FBP (Filtered Back Projection), a successive approximation method, etc.). By configuring it, CT image data is generated. Further, the reconstruction processing function 443 stores the generated CT image data in the memory 41.

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

In the X-ray CT apparatus 1 shown in FIG. 1A, each processing function is stored in the memory 41 in the form of a program that can be executed by a computer. The processing circuit 44 is a processor that realizes a function corresponding to each program by reading a program from the memory 41 and executing the program. In other words, the processing circuit 44 in the state where each program is read has a function corresponding to the read program.

The word "processor" used in the above description means, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), or a programmable logic device (for example, a programmable logic device). It means a circuit such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). When the processor is, for example, a CPU, the processor realizes the function by reading and executing the program stored in the memory 41. On the other hand, when the processor is, for example, an ASIC, the program is directly incorporated in the circuit of the processor instead of storing the program in the memory 41. It should be noted that each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits may be combined to form one processor to realize its function. good. Further, a plurality of components in FIG. 1 may be integrated into one processor to realize the function.

The overall configuration of the X-ray CT apparatus 1 to which the CT gantry data wireless communication system according to the present embodiment is applied has been described above.

Here, the data indicating the X-ray monitoring result or the like acquired by the rotating unit 110 is transmitted to the fixed unit 120 by a transmission method such as an optical transmission method (MUDAT), a capacitance induction transmission method (SURCOM), or a wireless communication method. be able to. However, the former two transmission methods are not preferable because they are inconvenient to install, have a large occupied space, and have high costs. Therefore, in the present embodiment, a wireless communication system that performs wireless communication between the rotating unit 110 and the fixed unit 120 of the CT pedestal 10 is provided, and between the rotating unit 110 and the fixed unit 120 in the transmission method of the wireless communication. We are focusing on solving the problem of data exchange.

In the wireless communication transmission method, when wireless communication is performed between the rotating portion 110 and the fixed portion 120 of the CT pedestal 10, the wireless signal is transmitted during the rotation of the CT pedestal 10 due to the relative movement of the rotating portion 110. Signal transmission may not be stable due to frequency shift caused by the influence of the Doppler effect. The formula for calculating the frequency shift caused by the Doppler effect is shown in the following formula.
f = (V × fc) / c × cos θ

However, c is the optical speed, which is 3.0 × ¹⁰⁸ m / s, V is the moving speed of the wireless device on the signal receiving side with respect to the wireless device on the signal transmitting side, and this moving speed V is a fixed value. , Obtained from the rotational speed of the CT mount 10, fc is the frequency of the signal electromagnetic wave of the wireless device on the signal transmission side, and this fc is a fixed value, which is determined by the performance of the device itself. , Θ are the angles formed by the transmission direction of the wireless signal and the motion direction of the wireless device on the signal transmitting side that transmits the wireless signal to the wireless device on the signal receiving side, and f is the frequency deviation amount of the wireless device corresponding to the angle θ. Is.

Each wireless device has a value of the rated frequency deviation amount after shipment, and in order to guarantee the stability of data transmission, the received signal satisfies the requirement of the rated frequency deviation amount, so that the maximum frequency deviation amount is reached. It is desirable that it is smaller than the value. Further, it is desirable to reduce the amount of frequency deviation by reducing the influence of the Doppler effect received.

Therefore, the CT pedestal data wireless communication system according to the present embodiment is convenient to install and has a small volume in the CT pedestal data wireless communication system that performs wireless communication between the rotating portion 110 and the fixed portion 120 of the CT pedestal 10. In order to realize stable signal transmission at low cost, it is configured as follows. The CT pedestal data wireless communication system according to the present embodiment is a first communication device which is a wireless device attached to the rotating portion 110 of the CT pedestal 10 and a wireless device attached to the fixed portion 120 of the CT pedestal 10. It includes a second communicator and a plurality of extended antennas that are electrically connected to one of the first communicator and the second communicator and perform wireless communication with the other. When the first communication device transmits the data acquired by the rotating unit 110 as a wireless signal, when the second communication device uses a plurality of extended antennas as the receiving side antennas, the plurality of extended antennas are the fixed unit 120. It is preferable that the fixing portion 120 is attached to the peripheral surface of the fixing portion 120 so as to equally divide the peripheral length of the inner peripheral surface of the fixed portion 120. On the other hand, when the first communication device uses a plurality of extended antennas as the antennas on the transmitting side, the plurality of extended antennas are placed on the peripheral surface of the rotating portion 110 so as to equally divide the peripheral surface of the rotating portion 110. It is preferable to be attached.

Further, the CT gantry data wireless communication system further includes a switching circuit 19 that realizes the function of the switching unit (or also referred to as a selection unit). The switching circuit 19 selects and switches the expansion antenna having a small influence of the Doppler effect from the plurality of expansion antennas as the rotating portion 110 of the CT mount 10 rotates. Specifically, for example, when the first communication device transmits the data acquired by the rotating unit 110 as a wireless signal, when the second communication device uses a plurality of extended antennas as the antennas on the receiving side, the switching is performed. The circuit 19 selects the expansion antenna having the closest angle between the direction from the first communication device toward the expansion antenna and the movement direction of the first communication device among the plurality of expansion antennas. On the other hand, when the first communication device transmits the data acquired by the rotating unit 110 as a wireless signal, when the first communication device uses a plurality of extended antennas as the transmitting side antennas, the switching circuits 19 are plural. Among the extended antennas in the above, the extended antenna in which the angle between the direction from the second communication device toward the extended antenna and the moving direction of the extended antenna is the closest to the right angle is selected.

FIG. 2 is a diagram showing an example of the configuration of the CT mount data wireless communication system according to the first embodiment. The CT gantry data wireless communication system of the present embodiment includes a first communication device 101, a second communication device 102, and expansion antennas 103-1 to 103-4 as a plurality of expansion antennas 103. FIG. 2 illustrates the case where there are four expansion antennas 103, but the number of expansion antennas 103 is not limited to this, and a method for determining the number of expansion antennas 103 will be described in detail later. do.

As shown in FIG. 2, the first communication device 101 is provided on the rotating portion 110 of the CT pedestal 10, and the second communication device 102 is provided on the fixed portion 120 of the CT gantry 10. The extended antennas 103-1 to 103-4 of the above are provided on the peripheral surface of the fixed portion 120 of the CT pedestal 10 so as to be evenly spaced, and the second extended antennas 103-1 to 103-4 are also provided on the fixed portion 120 via a cable. It is electrically connected to the communication device 102 of. In the example shown in FIG. 2, the CT pedestal 10 has a hollow bore formed in a substantially cylindrical shape, and when considering a polar coordinate system with the center of the bore as the origin, the circumference of the extended antenna 103-1 Assuming that the position in the direction is π [rad], the position of the expansion antenna 103-2 is π / 2, the position of the expansion antenna 103-3 is 0, and the position of the expansion antenna 103-4 is 3π / 2 (-π / 2). It is placed in the position of. The plurality of extended antennas 103-1 to 103-4 are provided at positions that are easy to attach / detach and do not interfere with other members, for example, in the frame of the fixed portion 120 of the CT mount 10.

Further, as shown in FIG. 2, it is preferable that the first communication device 101 is provided on the outer diameter of the rotating portion 110 of the CT pedestal 10 and the antenna direction is directed to the fixed portion 120 side. By providing it on the outer diameter of the rotating portion 110, obstacles between the first communication device 101 and the expansion antenna 103 provided on the fixed portion 120 of the CT pedestal 10 can be reduced, and the reflection of electromagnetic waves can be reduced. It can improve the stability of signal transmission.

Further, in order to avoid electromagnetic radiation, the second communication device 102 may be mounted at a position away from the motor.

In the present embodiment, the plurality of extended antennas 103-1 to 103-4 are provided independently of the first communication device 101 and the second communication device 102, and are provided according to the rotation angle of the rotating portion 110. One of the plurality of extended antennas 103-1 to 103-4 is used as an antenna connected to the first communication device 101 to receive a radio signal. By using the extended antenna 103, the fluctuation range of the frequency deviation is reduced as compared with the case where the extended antenna 103 is not used, and the maximum value of the frequency deviation amount is made smaller than the rated frequency deviation amount of the wireless device used. It has the effect of improving communication stability and ensuring the transmission rate.

Further, in the present embodiment, the plurality of extended antennas 103-1 to 103-4 are provided by the second communication device 102 when the first communication device 101 transmits the data acquired by the rotating unit 110 as a wireless signal. It is used as an antenna on the receiving side. Specifically, the first communication device 101 and the second communication device 102 transmit and receive radio signals as follows. For example, when scanning is performed, a control signal is transmitted from the processing circuit 44 to the second communication device 102 provided in the fixed portion 120 of the CT pedestal 10, and in the CT gantry 10, the second communication device 102 receives the second communication device 102. The control signal is transmitted by a wireless signal from the expansion antenna 103 selected by the switching circuit 19 among the plurality of expansion antennas 103-1 to 103-4 to the first communication device 101 provided in the rotating unit 110. .. By performing the scan on the CT mount 10, data such as projection data is acquired by the X-ray detector 12 of the rotating unit 110. The first communication device 101 transmits the data acquired by the rotating unit 110 by a wireless signal, and the second communication device 102 of the fixed unit 120 is a switching circuit among the plurality of extended antennas 103-1 to 103-4. The radio signal is received by the extended antenna 103 selected by 19. Then, the data received by the second communication device 102 as a wireless signal is transmitted to the processing circuit 44. Here, in the first embodiment, when the first communication device 101 provided in the rotating unit 110 transmits a wireless signal to the second communication device 102 provided in the fixed unit 120, the second communication device 101 is second. The case where the communication device 102 of the above uses the extended antenna 103 as the antenna on the receiving side will be described as an example. In this case, the switching circuit 19 selects one of the plurality of extended antennas 103-1 to 103-4 by the antenna switching method described later.

Here, as a comparative example, the amount of frequency deviation when the extended antenna 103 is not used will be described below with reference to FIGS. 3A to 3B. In each figure, the solid circle indicates the fixed portion 120 of the CT pedestal 10, the broken line circle indicates the rotating portion 110 of the CT pedestal 10, and the first communication device 101 is attached to the rotating portion 110 of the CT pedestal 10. The second communication device 102 is attached to the fixed portion 120 of the CT frame 10. The solid arrow indicates the motion direction Dm of the first communication device 101, and the alternate long and short dash arrow indicates the radio signal transmission direction Ds. Although the same reference numerals are used in FIGS. 4A to 4G to omit overlapping description, the expansion antennas 103 are further spaced at equal intervals in FIGS. 4A to 4G as compared with FIGS. 3A to 3D. The case where it is attached to the inner peripheral surface of the fixing portion 120 is exemplified.

When the expansion antenna 103 is not used and the rotating portion 110 rotates once, the range of change in the angle θ between the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101 is 0 ° to 180 °. It is known that the value of cos θ varies between -1 and 1.

Specifically, FIGS. 3A to 3D show four states in which the first communication device 101 rotates with respect to the second communication device 102. In FIG. 3A, the first communication device 101 is located at a far end position facing the second communication device 102 along the axial direction, and at this time, the transmission direction Ds of the radio signal and the first communication device 101. The angle θ formed by the motion direction Dm of is 90 °, and cos θ is 0. FIG. 3B shows immediately after the first communication device 101 reaches the vicinity of the second communication device 102, and at this time, the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101. The angle θ formed by the eggplant was close to 0, the θ angle changed from 90 ° to 0 °, and the cos θ changed from 0 to 1, as compared with FIG. 3A. During the process of FIGS. 3A to 3B, the amount of frequency shift is positive.

FIG. 3C shows the timing immediately before the first communication device 101 leaves the vicinity of the second communication device 102, and at this time, the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101 are shown. The angle θ formed was close to 180 °, the θ angle changed from 0 ° to 180 °, and cos θ changed from 1 to -1 as compared with FIG. 3B. In FIG. 3D, the first communicator 101 returns to the same position as in FIG. 3A, at which time the angle θ changes to 90 °, the θ angle changes from 180 ° to 90 °, and cos θ, as compared to FIG. 3C. Changed from -1 to 0. During the process of FIGS. 3C to 3D, the amount of frequency shift is negative.

As a result, according to the calculation formula of the frequency deviation caused by the above-mentioned Doppler effect, the frequency deviation amount f changes between −V × fc / c and + V × fc / c when the extended antenna 103 is not used. I understand.

Hereinafter, the antenna switching method in the present embodiment will be described with reference to FIGS. 4 and 5. First, with reference to FIGS. 4A to 4G, the principle of switching the extended antenna 103 having a good communication effect according to the change in the amount of frequency deviation when the extended antenna 103 is used and the rotation angle will be described.

In the following description, it is assumed that the expansion antenna 103 is used and the number of expansion antennas 103 is 4, but the number of expansion antennas 103 exemplified here is only an example, and stable transmission of signals is performed. In order to guarantee, the number of extended antennas 103 must be equal to or greater than the number of antennas obtained by the calculation formula described later.

When the extended antennas 103-1 to 103-4 are used as the four extended antennas 103, when the rotating portion 110 is rotated by 90 °, the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101 The range of change of the angle θ is 90 ° to 67.5 ° and 112.5 ° to 90 °, and the value of cosθ always changes between 0 to 0.383 and −0.383 to 0.

Specifically, FIGS. 4A to 4D show a case where the first communication device 101 is rotated by 90 ° with respect to the second communication device 102. In FIGS. 4A to 4D, when a plurality of expansion antennas 103-1 to 103-4 are provided, the first communication device 101, the second communication device 102, and the expansion antennas 103-1 to 103-4 are provided. Although the relative positional relationship of is illustrated, the installation position of each member is not limited to the position shown in the figure. In FIG. 4A, in the four extended antennas 103-1 to 103-4, the angle θ formed by the motion direction Dm of the first communication device 101 and the extended antenna 103-3 is 90 °, cos θ is 0, and the frequency deviation amount is shown. Is 0, and at this time, the communication effect between the expansion antenna 103-3 and the first communication device 101 is the best.

If the rotating portion 110 is rotated 45 ° clockwise and the first communication device 101 is about to reach the position shown in FIG. 4B, the first communication is performed by the four extended antennas 103-1 to 103-4. The angle θ between the motion direction Dm of the machine 101 and the extended antenna 103-3 is 67.5 °, the cos θ is 0.383, and the frequency deviation amount is 0.383 × V × fc / c. At this time, the extended antenna The communication effect between 103-3 and the first communication device 101 is the best.

If the rotating portion 110 continues to rotate clockwise and immediately after leaving the position shown in FIG. 4B, the state shown in FIG. 4C is reached. In this case, in the four extended antennas 103-1 to 103-4, the angle θ formed by the motion direction Dm of the first communication device 101 and the extended antenna 103-4 is 112.5 °, and the cos θ is −0.383. The amount of frequency deviation is −0.383 × V × fc / c, and the communication effect between the extended antenna 103-4 and the first communication device 101 is the best. When the rotating portion 110 continues to rotate clockwise and reaches the position shown in FIG. 4D, in the four expansion antennas 103-1 to 103-4, the movement direction Dm of the first communication device 101 and the expansion antenna 103- The angle θ formed with 4 is 90 °, cos θ is 0, and the amount of frequency deviation is 0. At this time, the communication effect between the extended antenna 103-4 and the first communication device 101 is the best.

As a result, between FIGS. 4A and 4D, the expansion antenna 103 having the best communication effect is switched from the expansion antenna 103-3 to the expansion antenna 103-4.

Further, FIGS. 4E to 4G show that the rotation continues clockwise with respect to the position shown in FIG. 4D. If the rotating portion 110 rotates 45 ° clockwise from the position shown in FIG. 4D and is just before reaching the position shown in FIG. 4E, the first communication device is used in the four extended antennas 103-1 to 103-4. The angle θ formed by the motion direction Dm of 101 and the extended antenna 103-4 is 67.5 °, the cos θ is 0.383, and the frequency deviation amount is 0.383 × V × fc / c. At this time, the extended antenna 103 The communication effect between -4 and the first communication device 101 is the best.

If the rotating portion 110 continues to rotate clockwise and immediately after leaving the position shown in FIG. 4E, the state shown in FIG. 4F is reached. In this case, in the four extended antennas 103-1 to 103-4, the angle θ formed by the motion direction Dm of the first communication device 101 and the extended antenna 103-1 is 112.5 °, and the cos θ is −0.383. The amount of frequency deviation is −0.383 × V × fc / c, and the communication effect between the extended antenna 103-1 and the first communication device 101 is the best.

When the rotating portion 110 continues to rotate clockwise and reaches the position shown in FIG. 4G, the moving direction Dm of the first communication device 101 and the extended antenna 103-1 in the four extended antennas 103-1 to 103-4. The angle θ between the antenna and the antenna is 90 °, the cos θ is 0, and the amount of frequency deviation is 0. At this time, the communication effect between the extended antenna 103-1 and the first communication device 101 is the best.

As a result, during the period of FIGS. 4E to 4G, the expansion antenna 103 having the best communication effect is switched from the expansion antenna 103-4 to the expansion antenna 103-1.

When four extended antennas 103-1 to 103-4 are used, the frequency shift amount f changes between −0.383 × V × fc / c to +0.383 × V × fc / c, and the extended antenna 103 Compared with −V × fc / c to + V × fc / c when is not used, the frequency deviation amount f is reduced and the communication effect is improved.

FIG. 5 shows the extended antenna 103 selected when a plurality of extended antennas 103-1 to 103-4 are on the fixed portion 120 side of the CT pedestal 10 in the CT pedestal data wireless communication system according to the first embodiment. Shows in the form of a table the situation in which is switched according to the rotation of the CT mount 10.

In FIG. 5, the expansion antenna 103-1, the expansion antenna 103-2, the expansion antenna 103-3, and the expansion antenna 103-4 are arranged on the inner circumference of the fixed portion 120 at 90 ° intervals, and the first communication device 101 The angle position closest to the extended antenna 103-2 is 0 [rad]. It is assumed that the distance from the rotation center to the reception position of each extended antenna 103 is equal to r2, and the distance from the rotation center to the transmission position of the first communication device 101 is always r1. In actual use, the distance from the center of rotation to each expansion antenna 103 is generally almost the same as the distance from the center of rotation to the first communication device 101, that is, the first communication device 101. When the expansion antenna 103 is at the same angle position, the distance between the two is close and the gap between the two is negligible. Therefore, in FIG. 5, it is further described as r1≈r2. Even if the difference between the distance r1 and the distance r2 cannot be ignored with respect to the magnitudes of the distances r1 and r2, the angular position Φ of the first communication device 101 to which the extended antenna 103 to be communicated is switched is nπ /. It is the same as 4 (0 ≦ n, n ∈ Z), but the influence of the Doppler effect on the radio signal depends on the distance r1 and the distance r2. In this case, the above-mentioned cosθ indicating the influence of the Doppler effect is sinξ satisfying approximately sin (π / 4-ξ) / sinξ = r1 / r2.

Further, in the table shown in FIG. 5, the direction from the first communication device 101 toward the expansion antenna 103 (radio signal transmission direction Ds) and the first communication device 101 according to the change in the position of the first communication device 101. It shows the change of the angle with the moving direction Dm of the above, and also shows the extended antenna 103 selected when the first communication device 101 is located at a different position on the circumference.

Specifically, in the table shown in FIG. 5, the angular position Φ of the first communication device 101 is 0, π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4. It is shown that the expansion antenna 103 is switched at the position of 2π, and the shaded portion in FIG. 5 indicates that the angle is closest to the right angle. As can be seen from FIG. 5, at each angle position Φ of the first communication device 101, the direction from the first communication device 101 toward the diffusion antenna 103 itself among the plurality of extended antennas 103-1 to 103-4. The extended antenna 103 whose angle formed by the movement direction Dm of the first communication device 101 is closest to a right angle is selected.

For example, when the angle position Φ of the first communication device 101 is 0, the angle formed by the direction from the first communication device 101 toward the expansion antenna 103-3 and the motion direction Dm of the first communication device 101 is shown in FIG. As shown by the shaded area of 5, it is π / 2, and the extended antenna 103-3 is selected. Details are as shown in FIGS. 4A to 4G described above.

When the extended antenna 103 is switched, the antenna is switched depending only on the magnitude relationship of the Doppler effect, but the first communication device 101 is rotated from 0 to π / 4, for example, as the angular position. In this case, the effect of the instantaneous Doppler effect is the same for the extended antenna 103-3 and the extended antenna 103-4. In this case, as shown in FIGS. 4B and 4C, the expansion antenna 103 depends on the timing immediately after the angular position Φ of the first communication device 101 reaches π / 4 and the timing immediately before leaving π / 4. -3 and the extended antenna 103-4 are switched.

That is, as shown in FIG. 4B, at the timing immediately after the angular position Φ of the first communication device 101 reaches π / 4, the direction from the first communication device 101 toward the expansion antenna 103-3 and the first communication. The angle formed by the moving direction Dm of the machine 101 is 3π / 8, as shown by the shaded area in FIG. 5, and the extended antenna 103-3 is selected. Further, as shown in FIG. 4C, at the timing immediately before the angular position Φ of the first communication device 101 departs from π / 4, the direction from the first communication device 101 toward the expansion antenna 103-4 and the first communication device The angle formed by the motion direction Dm of 101 is 5π / 8, as shown by the shaded portion in FIG. 5, and the extended antenna 103-4 is selected.

According to the above description, when a plurality of extended antennas 103 are used, the extended antenna 103 having the optimum communication effect is switched according to the angle formed by the motion direction Dm of the first communication device 101 and the transmission direction Ds of the radio signal. And the amount of frequency shift can be reduced.

Further, the maximum frequency deviation amount fd of each wireless device is determined by a parameter unique to itself, and each wireless device has a rated frequency deviation value after shipment. In order to guarantee the stability of data transmission, it is desirable that the signal received by the wireless device satisfies the requirement of the frequency deviation amount of the wireless device, that is, it is smaller than the maximum value of the frequency deviation amount.

It is also known that the larger the number of extended antennas 103 used, the smaller the amount of frequency deviation.

Therefore, the minimum number of extended antennas 103 can be obtained by using the maximum value fd of the frequency deviation amount of each wireless device.

Hereinafter, a method of deriving the calculation formula for the number of the extended antennas 103 will be described with reference to FIGS. 6A to 6C.

As shown in FIG. 6A, when the rotating portion 110 rotates clockwise, the first communication device 101 fixed to the rotating portion 110 rotates clockwise, and accordingly, the transmission direction Ds of the radio signal is increased. The angle formed by the movement direction Dm of the first communication device 101 changes. In the example shown in FIG. 6A, when the angle θ ₁ formed by the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101 is 90 °, the rotating portion 110 rotates clockwise at about 30 ° and 60. When rotated by °, the angles formed by the transmission direction Ds of the radio signal and the motion direction Dm of the first communication device 101 are set to θ ₂ and θ ₃ , respectively. In this case, the relationship between the angles θ ₁ , θ ₂ and θ ₃ is θ ₁ > θ ₂ > θ ₃ .

Here, in the calculation formula of the frequency deviation caused by the Doppler effect, according to f = V × fc × cos θ / c, the signal gradually increases as cos θ increases in response to the conversion of the angles θ ₁ to θ ₃ . The frequency deviation amount f gradually increases. Assuming that the frequency deviation amount f corresponding to the angle θ ₃ is the maximum frequency variation range that can be received by the second communication device 102, the angle θ ₃ is the transmission direction Ds of the radio signal and the first communication device 101. It is considered that the critical value θ _Limit (hereinafter, abbreviated as θ _L ) of the angle formed with the motion direction Dm. Assuming that the central angle formed by the angle θ ₃ , that is, the position of the angle θ _L and the initial position of the first communication device 101 is α, as shown in FIG. 6B, α = 2 × (90 ° −θ _L ). It becomes.

As shown in FIG. 6C, the effective reception range of the second communication device 102 is α degrees in each of the clockwise and counterclockwise directions from the position on the circumference facing the second communication device 102. It is a rotating range, and any signal transmitted in this range can be effectively received by the second communication device 102. As a result, the effective reception range of each extended antenna 103 becomes 2α.

In order for the receivable range of the second communication device 102 to cover the entire area, it is necessary to increase the number of antennas of the second communication device 102, and the maximum frequency deviation amount fd of the wireless device is required. In order to satisfy the condition, the actual frequency deviation amount must be equal to or less than the maximum frequency deviation amount fd while the rotating portion 110 is moving.

In response to the above requirement, the required number N of the expansion antenna 103 can be obtained by the following equations (1) and (2).
cosθ _L = fd / (V × fc / c) (1)
N = 360 ° / 2α = 360 ° / [4 × (90 ° −θ _L )]
= 90 ° / (90 ° -θ _L ) (2)

However, c is the speed of light, which is 3.0 × ¹⁰⁸ m / s, V is the moving speed of the second communication device 102 with respect to the first communication device 101, and fc is the movement speed of the first communication device 101. Signal The frequency of electromagnetic waves. θ _L is a critical value of the angle formed by the transmission direction Ds of the radio signal transmitted from the signal transmission unit and the motion direction Dm of the signal transmission unit, and the plurality of extended antennas 103-1 to 103-4 are antennas on the receiving side. When used as, the signal transmission unit is the first communication device 101 itself. On the other hand, when a plurality of extended antennas 103-1 to 103-4 are used as transmission side antennas as in the second embodiment described later, the signal transmitting unit has a plurality of extended antennas 103-1 to 103-. It is one of 4. fd is the maximum frequency deviation amount allowed by the second communication device 102.

The case where a plurality of extended antennas 103-1 to 103-4 are used in the CT mount 10 has been described above. By using a plurality of extended antennas 103-1 to 103-4, it is possible to reduce the fluctuation range of the frequency deviation of the wireless device. The range in which the frequency changes is related to the number of extended antennas 103 used, and the larger the number of extended antennas 103, the smaller the fluctuation amount of the frequency deviation.

The present embodiment provides a method for calculating the minimum number of extended antennas 103. The minimum of the extended antenna 103 is obtained by obtaining the critical value of the angle formed by the transmission direction Ds of the radio signal and the motion direction Dm of the signal generator based on the maximum frequency variation range that can be received by the second communication device 102. The number of can be calculated.

By adopting this embodiment, a sufficient amount of antennas can be provided, the actual frequency deviation amount can be kept within the maximum allowable value of the frequency deviation amount of the wireless device to be used, and communication can be performed. It has the effect of improving stability and ensuring the transmission rate.

According to the above description, the CT pedestal data wireless communication system according to the first embodiment has the first communication device 101, which is a wireless device attached to the rotating portion 110 of the CT pedestal 10, and the fixed portion 120 of the CT pedestal 10. A plurality of extended antennas that are electrically connected to the second communication device 102, which is a wireless device attached to the device, and one of the first communication device 101 and the second communication device 102, and perform wireless communication with the other. 103-1 to 103-4 are provided, and a plurality of expansion antennas 103-1 to 103-4 are attached to the peripheral surface of the fixed portion 120.

As a result, in the CT pedestal data wireless communication system according to the first embodiment, effects such as convenient installation, small volume, and low cost can be realized as compared with the optical transmission method and the capacity induction transmission method. Further, according to the CT pedestal data wireless communication system according to the first embodiment, a plurality of extended antennas 103-1 to 103-4 are provided on the peripheral surface of the fixed portion 120, and the rotating portion 110 is rotated. The expansion antenna 103 having the optimum communication effect is freely switched between the plurality of expansion antennas 103-1 to 103-4, and the first communication device 101, which is a wireless device on the signal transmitting side for transmitting a wireless signal, and the wireless signal. Since data can be transmitted to and from the second communication device 102, which is a wireless device on the signal receiving side, stable signal transmission can be realized.

Further, in the CT frame data wireless communication system according to the first embodiment, the plurality of extended antennas 103-1 to 103-4 are attached to the fixed portion 120 and electrically connected to the second communication device 102. The CT gantry data wireless communication system receives a radio signal from the first communication device 101 on any of the plurality of extended antennas 103-1 to 103-4 according to the rotation angle of the CT gantry 10. It also has a switching unit that switches as an antenna on the receiving side.

Further, in the CT frame data wireless communication system according to the first embodiment, the plurality of extended antennas 103-1 to 103-4 are attached to the fixed portion 120 and electrically connected to the second communication device 102. The CT gantry data wireless communication system has a direction from the first communication device 101 toward the expansion antenna 103 and a movement direction of the first communication device 101 among a plurality of expansion antennas 103-1 to 103-4. Further, it has a selection unit for selecting the extended antenna 103 whose angle formed by Dm is closest to 90 °. As described above, in the CT mount data wireless communication system according to the first embodiment, the switching circuit 19 that realizes the functions of the selection unit and the switching unit has a plurality of extended antennas as the rotating unit 110 of the CT frame 10 rotates. The extended antenna 103, which is less affected by the Doppler effect, is selected from 103-1 to 103-4 and switched.

As a result, in the CT mount data wireless communication system according to the first embodiment, a plurality of extended antennas 103-1 to 103-4 are attached to the second communication device 102 side, and the antennas on the second communication device 102 side. By switching the extended antenna 103 at the optimum communication position according to the rotation angle of the rotating unit 110, stable signal transmission can be realized.

Further, in the CT pedestal data wireless communication system according to the first embodiment, the plurality of extended antennas 103-1 to 103-4 are attached at positions that substantially divide the peripheral length on the peripheral surface of the fixed portion 120. .. As a result, in the CT mount data wireless communication system according to the first embodiment, when the influence of the Doppler effect is avoided, the positions of the plurality of extended antennas 103-1 to 103-4 are substantially equally divided on the peripheral surface. It should be attached to. In this case, the installation position of the expansion antenna 103 can be determined by a simple method.

Further, in the CT gantry data wireless communication system according to the first embodiment, the transmission direction Ds of the wireless signal transmitted from the signal transmission unit and the said are based on the maximum frequency variation range that can be received by the second communication device 102. The critical value of the angle formed by the motion direction Dm of the signal transmission unit is obtained. As a result, the minimum number of the expansion antennas 103 is calculated, and the minimum number of the plurality of expansion antennas 103-1 to 103-4 are provided on the inner peripheral surface of the fixed portion 120 at equal intervals, and the number N of the expansion antennas 103 is , It is obtained by calculation by the above-mentioned calculation formulas (1) and (2). As described above, in the CT pedestal data wireless communication system according to the first embodiment, the minimum number of antennas satisfying the maximum frequency variation that can be received by the second communication device 102 is calculated, and stable signal transmission is possible. Become.

Further, in the CT frame data wireless communication system according to the first embodiment, the first communication device 101 is attached to the outer diameter of the rotating portion 110. As a result, in the CT frame data wireless communication system according to the first embodiment, there is no obstacle between the first communication device 101 and the fixed portion 120, the signals are interfered with, and the communication efficiency is lowered. Can be avoided.

Further, in the CT frame data wireless communication system according to the first embodiment, the plurality of extended antennas 103-1 to 103-4 are provided in the frame of the fixed portion 120. As a result, in the CT mount data wireless communication system according to the first embodiment, the plurality of extended antennas 103-1 to 103-4 are provided at positions that are easy to attach / detach and do not interfere with other members. ..

Further, in the CT frame data wireless communication system according to the first embodiment, the second communication device 102 is provided at a position away from the motor. As a result, in the CT frame data wireless communication system according to the first embodiment, the second communication device 102 is less likely to receive electromagnetic wave interference from the motor.

Further, the CT pedestal data wireless communication system according to the first embodiment relates to the CT pedestal 10 and the X-ray CT device 1, and has the above-mentioned CT pedestal data wireless communication system. Thereby, in the first embodiment, the CT pedestal 10 and the X-ray CT device 1 in which the signal transmission is stable can be realized.

In the first embodiment, when the first communication device 101 provided in the rotating unit 110 transmits a radio signal to the second communication device 102 provided in the fixed unit 120, the second communication device 101 is used. When the communication device 102 uses the extended antenna 103 as the antenna on the receiving side, the switching circuit 19 selects one of a plurality of extended antennas 103-1 to 103-4 by the above-mentioned antenna switching method. Not limited to. For example, in the first embodiment, when the second communication device 102 provided in the fixed unit 120 transmits a radio signal to the first communication device 101 provided in the rotating unit 110, the second communication device 102 is used. Even when the communication device 102 uses the extended antenna 103 as the antenna on the transmitting side, the switching circuit 19 selects one of the plurality of extended antennas 103-1 to 103-4 by the above-mentioned antenna switching method.

(Second embodiment)
In the first embodiment, the CT gantry data wireless communication system includes a first communication device 101, a second communication device 102, and a plurality of extended antennas 103-1 to 103-4, and the first communication. The machine 101 is provided on the outer diameter of the rotating portion 110, and the plurality of extended antennas 103-1 to 103-4 and the second communication device 102 are both provided on the fixed portion 120 and electrically connected to each other. The plurality of extended antennas 103-1 to 103-4 are provided on the inner peripheral surface of the fixed portion 120 at equal intervals, function as antennas on the signal receiving side, and are the first communication device by a wireless method. Receive a radio signal from 101.

Also in the CT gantry data wireless communication system of the second embodiment, as in the first embodiment, the first communication device 101, the second communication device 102, and the plurality of extended antennas 103-1 to 103- The first communication device 101 is provided in the rotating portion 110, and the plurality of expansion antennas 103-1 to 103-4 are provided at equal intervals.

Here, in the second embodiment, as compared with the first embodiment, the plurality of extended antennas 103-1 to 103-4 and the first communication device 101 are both provided in the rotating portion 110 and are electrically connected to each other. The difference is that they are connected to each other. Further, in the second embodiment, as compared with the first embodiment, in the plurality of extended antennas 103-1 to 103-4, the first communication device 101 transmits the data acquired by the rotating unit 110 as a wireless signal. It differs in that it is used as an antenna on the transmitting side by the first communication device 101. Specifically, the first communication device 101 and the second communication device 102 transmit and receive radio signals as follows. For example, when scanning is performed, a control signal is transmitted from the processing circuit 44 to the second communication device 102 provided in the fixed portion 120 of the CT pedestal 10, and in the CT gantry 10, the second communication device 102 receives the second communication device 102. The control signal is transmitted by a wireless signal, and the first communication device 101 provided in the rotating unit 110 is the expansion antenna 103 selected by the switching circuit 19 among the plurality of expansion antennas 103-1 to 103-4. , Receive the radio signal. By performing the scan on the CT mount 10, data such as projection data is acquired by the X-ray detector 12 of the rotating unit 110. The first communication device 101 uses a wireless signal to transmit the data acquired by the rotating unit 110 from the extended antenna 103 selected by the switching circuit 19 among the plurality of extended antennas 103-1 to 103-4 to the fixed unit 120. It is transmitted to the second communication device 102. Then, the data received by the second communication device 102 as a wireless signal is transmitted to the processing circuit 44. Here, in the second embodiment, when the first communication device 101 provided in the rotating unit 110 transmits a radio signal to the second communication device 102 provided in the fixed unit 120, the first communication device 101 is used. The case where the communication device 101 of the above uses the extended antenna 103 as the antenna on the transmitting side will be described as an example. In this case, the switching circuit 19 selects one of the plurality of extended antennas 103-1 to 103-4 by the antenna switching method described above.

Specifically, the plurality of extended antennas 103-1 to 103-4 are signal transmitters, and the radio signal is a second communication device from the extended antenna 103 of one of the plurality of extended antennas 103-1 to 103-4. The critical value θ _L transmitted to 102 and at cos θ _L = fd / (V × fc / c) is the transmission direction Ds of the radio signal transmitted from one extended antenna 103 and the motion direction Dm of the one extended antenna 103. It is calculated based on.

In the present embodiment, a plurality of extended antennas 103-1 to 103-4 are provided in the rotating unit 110 together with the first communication device 101 as signal transmitting side antennas, and in this case, the first communication in the rotating unit 110. The position of the machine 101 is not limited, but in order to reduce obstacles and obtain a good transmission effect, a plurality of extended antennas 103-1 to 103-4 are placed on the outer diameter of the rotating portion 110, that is, on the outer peripheral surface. It is preferable to be attached.

Also in the second embodiment, a sufficient amount of antennas can be provided, the actual frequency deviation amount can be kept within the maximum allowable value of the frequency deviation amount of the wireless device to be used, and the communication stability is improved. And it has the effect of securing the transmission rate.

In the above embodiment, the N extended antennas 103-i (i = 1, 2, ... N) are positioned at positions that equally divide the outer circumference of the rotating portion 110 / the inner circumference (perimeter) of the fixed portion 120. When arranging, the position where each extended antenna 103 is arranged is 2π × (i-1) / N in the polar coordinate system with the center of the bore of the CT gantry 10 as the origin.

According to the above description, the CT pedestal data wireless communication system according to the second embodiment has the first communication device 101, which is a wireless device attached to the rotating portion 110 of the CT pedestal 10, and the fixed portion 120 of the CT pedestal 10. A plurality of extended antennas that are electrically connected to the second communication device 102, which is a wireless device attached to the device, and one of the first communication device 101 and the second communication device 102, and perform wireless communication with the other. 103-1 to 103-4 are provided, and a plurality of expansion antennas 103-1 to 103-4 are attached to the peripheral surface of the rotating portion 110.

As a result, in the CT pedestal data wireless communication system according to the second embodiment, effects such as convenient installation, small volume, and low cost can be realized as compared with the optical transmission method and the capacity induction transmission method. Further, according to the CT pedestal data wireless communication system according to the first embodiment, a plurality of extended antennas 103-1 to 103-4 are provided on the peripheral surface of the rotating portion 110, and the rotating portion 110 is rotated. The expansion antenna 103 having the optimum communication effect is freely switched between the plurality of expansion antennas 103-1 to 103-4, and the first communication device 101, which is a wireless device on the signal transmitting side for transmitting a wireless signal, and the wireless signal. Data can be transmitted to and from the second communication device 102, which is a wireless device on the signal receiving side, and stable signal transmission can be realized.

Further, in the CT frame data wireless communication system according to the second embodiment, a plurality of extended antennas 103-1 to 103-4 are attached to the rotating portion 110 and are electrically connected to the first communication device 101. , The CT gantry data wireless communication system transmits a radio signal to the second communication device 102 by any one of a plurality of extended antennas 103-1 to 103-4 according to the rotation angle of the CT gantry 10. It also has a switching unit that switches as a side antenna.

Further, in the CT frame data wireless communication system according to the second embodiment, the plurality of extended antennas 103-1 to 103-4 are attached to the rotating portion 110 and are electrically connected to the first communication device 101. In the CT mount data wireless communication system, the angle formed by the direction from the second communication device 102 toward the extended antenna 103 and the motion direction Dm of the extended antenna 103 among the plurality of extended antennas 103-1 to 103-4. Further has a selection unit that selects the extended antenna 103 that is closest to 90 °. As described above, in the CT mount data wireless communication system according to the second embodiment, the switching circuit 19 that realizes the functions of the selection unit and the switching unit has a plurality of extended antennas as the rotating unit 110 of the CT frame 10 rotates. The extended antenna 103, which is less affected by the Doppler effect, is selected from 103-1 to 103-4 and switched.

As a result, in the CT mount data wireless communication system according to the second embodiment, a plurality of extended antennas 103-1 to 103-4 are attached to the first communication device 101 side, and the antennas on the first communication device 101 side. By switching the extended antenna 103 at the optimum communication position according to the rotation angle of the rotating unit 110, stable signal transmission can be realized.

Further, in the CT pedestal data wireless communication system according to the second embodiment, the plurality of extended antennas 103-1 to 103-4 are attached at positions that substantially divide the peripheral length on the peripheral surface of the rotating portion 110. .. As a result, in the CT mount data wireless communication system according to the first embodiment, when the influence of the Doppler effect is avoided, the positions of the plurality of extended antennas 103-1 to 103-4 are substantially equally divided on the peripheral surface. It should be attached to. In this case, the installation position of the expansion antenna 103 can be determined by a simple method.

Further, in the CT gantry data wireless communication system according to the second embodiment, the transmission direction Ds of the wireless signal transmitted from the signal transmission unit and the said are based on the maximum frequency variation range that can be received by the second communication device 102. The critical value of the angle formed by the motion direction Dm of the signal transmission unit is obtained. As a result, the minimum number of the expansion antennas 103 is calculated, and the minimum number of the plurality of expansion antennas 103-1 to 103-4 are provided on the inner peripheral surface of the rotating portion 110 at equal intervals, and the number N of the expansion antennas 103 is N. Is calculated by the above-mentioned calculation formulas (1) and (2). As described above, in the CT gantry data wireless communication system according to the second embodiment, the minimum number of antennas satisfying the maximum frequency variation that can be received by the second communication device 102 is calculated, and stable signal transmission is possible. Become.

Further, in the CT frame data wireless communication system according to the second embodiment, the plurality of extended antennas 103-1 to 103-4 are attached to the outer diameter of the rotating portion 110. As a result, in the CT frame data wireless communication system according to the second embodiment, there is no obstacle between the plurality of extended antennas 103-1 to 103-4 and the fixed portion 120, and the signals are interfered with each other to improve the communication efficiency. It is possible to avoid a decrease.

In the second embodiment, when the first communication device 101 provided in the rotating unit 110 transmits a radio signal to the second communication device 102 provided in the fixed unit 120, the first communication device 101 is used. When the communication device 101 uses the extended antenna 103 as the antenna on the transmitting side, the switching circuit 19 selects one of a plurality of extended antennas 103-1 to 103-4 by the above-mentioned antenna switching method. Not limited to. For example, in the second embodiment, when the second communication device 102 provided in the fixed unit 120 transmits a radio signal to the first communication device 101 provided in the rotating unit 110, the first communication device 102 is used. Even when the communication device 101 uses the extended antenna 103 as the antenna on the receiving side, the switching circuit 19 selects one of the plurality of extended antennas 103-1 to 103-4 by the above-mentioned antenna switching method.

(Third embodiment)
In the first embodiment and the second embodiment, a plurality of extended antennas 103-1 to 103-4 are set so as to equally divide the outer circumference of the rotating portion 110 / the inner circumference (perimeter) of the fixed portion 120. The case was explained.

However, due to the influence of interference sources and obstacles, it is not guaranteed that the plurality of extended antennas 103-1 to 103-4 calculated by the above equations (1) and (2) are evenly distributed on the circumference. In some cases. Therefore, in order to avoid the influence of the Doppler effect, a plurality of extended antennas 103-1 to 103-4 can be set non-equally.

The difference between the third embodiment and the first embodiment / the second embodiment is that the plurality of extended antennas 103 are unequally divided into the outer circumference of the rotating portion 110 / the inner circumference (perimeter) of the fixed portion 120. It is to be provided as a target.

As an example, according to the influence of the Doppler effect, assuming that the maximum usage range of each extended antenna 103 is 90 ° as shown in FIG. 7A, each extended antenna is via at least four extended antennas 103-1 to 103-4. Stable transmission of data is guaranteed only when the effective range of 103 is set to 90 °. Therefore, depending on the actual situation, if a certain expansion antenna 103 cannot be arranged at a position where there is a difference of 90 ° from the adjacent expansion antenna 103, the number of expansion antennas 103 can be increased. For example, as shown in FIG. 7B, it is sufficient to guarantee that the angle between the two adjacent expansion antennas 103 among the six expansion antennas 103-1 to 103-6 is 90 ° or less. The angles formed by the adjacent extended antennas 103 do not have to be equal.

In the above-described embodiment, an example of selecting the expansion antenna 103 to be communicated in consideration of only the influence of the Doppler effect caused by the rotation of the rotating portion 110 has been shown, but the example of the embodiment is not limited to this. Factors that affect the quality of wireless communication are affected by other factors such as noise sources, transmission-reception distance, etc., in addition to Doppler. When considering effects other than the Doppler effect, the effect of the Doppler effect is only one factor and is judged comprehensively. For example, in consideration of communication obstruction due to a subject having a flat elliptical shape placed on a bed, the expansion antenna 103 is changed from the expansion antenna 103-3 to the expansion antenna 103 before reaching the angular position Φ = π / 4. You may switch to -4. Alternatively, if a device or the like embedded in the subject itself is the noise source, it is embedded in the subject itself as the noise source in the path from the first communication device 101 to each extended antenna 103. If there is such a device, the extended antenna 103 may be excluded from the selection target, and the extended antenna 103 may be selected from the remaining extended antenna 103 in consideration of the influence of the Doppler effect.

In the above-described embodiment, the switching circuit 19 is provided on the CT mount 10, but the switching circuit 19 is not limited to this, and for example, the function of the switching circuit 19 as a selection unit or a switching unit is provided on the console device 40. May be done. For example, in the console device 40, the processing circuit 44 further executes a switching function which is a function of the selection unit and the switching unit. Specifically, the processing circuit 44 reads a program from the memory 41 and executes the switching function. The switching function selects and switches the expansion antenna 103, which is less affected by the Doppler effect, from the plurality of expansion antennas 103 as the rotating portion 110 of the CT mount 10 rotates.

According to at least one embodiment described above, the mounting is convenient, the volume is small, the cost is low, and stable signal transmission can be realized.

Although some embodiments have been described, these embodiments are merely exemplary and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

10 Mount device (CT mount)
101 First communication device 102 Second communication device 103 Expansion antenna 110 Rotating frame (rotating part)
120 Fixed frame (fixed part)

Claims (13)

The first communication device, which is a wireless device attached to the rotating part of the CT frame,
A second communication device, which is a wireless device attached to the fixed portion of the CT frame, and
It is provided with a plurality of extended antennas that are electrically connected to one of the first communication device and the second communication device and that perform wireless communication with the other.
The plurality of extended antennas are a CT pedestal data wireless communication system attached to the peripheral surface of the rotating portion or the fixed portion. The plurality of extended antennas are attached to the fixed portion and electrically connected to the second communication device.
The first aspect of claim 1, further comprising a switching unit that switches any of the plurality of extended antennas as a receiving side antenna for receiving a radio signal from the first communication device according to the rotation angle of the CT frame. CT mount data wireless communication system. The plurality of extended antennas are attached to the fixed portion and electrically connected to the second communication device.
Among the plurality of expansion antennas, a selection unit for selecting an expansion antenna whose angle between the direction from the first communication device toward the expansion antenna and the movement direction of the first communication device is the closest to a right angle is further selected. The CT mount data wireless communication system according to claim 1. The plurality of extended antennas are attached to the rotating portion and electrically connected to the first communication device.
The first aspect of claim 1, further comprising a switching unit that switches any of the plurality of extended antennas as a transmitting side antenna for transmitting a radio signal to the second communication device according to the rotation angle of the CT frame. CT mount data wireless communication system. The plurality of extended antennas are attached to the rotating portion and electrically connected to the first communication device.
A claim further comprising a selection unit for selecting an expansion antenna having an angle formed by the direction from the second communication device toward the expansion antenna and the movement direction of the expansion antenna closest to a right angle among the plurality of expansion antennas. The CT mount data wireless communication system according to 1. The CT mount data communication system according to claim 1, wherein the plurality of extended antennas are attached at positions where the peripheral lengths of the rotating portion or the fixed portion are substantially equally divided. Based on the maximum frequency variation range that can be received by the second communication device, the critical value of the angle between the transmission direction of the radio signal transmitted from the signal transmission unit and the motion direction of the signal transmission unit is obtained. , The minimum number of the expansion antennas is calculated, and the minimum number of the plurality of expansion antennas are provided at equal intervals on the inner peripheral surface of the fixed portion or the rotating portion.
The number N of the extended antennas is calculated and obtained by the following calculation formulas (1) and (2).
cosθ _L = fd / (V × fc / c) (1)
N = 90 ° / (90 ° -θ _L ) (2)
However, c is the optical speed, which is 3.0 × ¹⁰⁸ m / s, V is the moving speed of the second communication device with respect to the first communication device, and fc is the moving speed of the first communication device. It is the frequency of the signal electromagnetic wave, θ _L is a critical value of the angle formed by the transmission direction of the radio signal transmitted from the signal transmission unit and the motion direction of the signal transmission unit, and the plurality of extended antennas are antennas on the transmission side. When the signal transmitting unit is one of a plurality of extended antennas and the plurality of extended antennas are used as receiving antennas, the signal transmitting unit is the first communication device. The CT pedestal data wireless communication system according to any one of claims 1 to 6, wherein fd is the maximum frequency deviation amount allowed by the second communication device. The CT mount data wireless communication system according to claim 2 or 3, wherein the first communication device is attached to the outer diameter of the rotating portion. The CT mount data wireless communication system according to claim 2 or 3, wherein the plurality of extended antennas are provided in a frame of the fixed portion. The CT mount data wireless communication system according to claim 4 or 5, wherein the plurality of extended antennas are attached to the outer diameter of the rotating portion. The CT frame data wireless communication system according to claim 1, wherein the second communication device is provided at a position away from the motor. The CT pedestal having the CT pedestal data wireless communication system according to any one of claims 1 to 11. An X-ray CT apparatus having the CT mount data wireless communication system according to any one of claims 1 to 11.

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