JP2019129939A - X-ray ct apparatus - Google Patents

Abstract

To provide an X-ray CT apparatus capable of reducing a burden of a contrast inspection on an operator.SOLUTION: The apparatus comprises: an X-ray tube 21 for applying an X-ray onto a subject P placed on a top plate 11; an X-ray detector 22 for detecting an X-ray applied by the X-ray tube 21 and transmitted through the subject P; and a top plate driving device 14 for moving the top plate 11. When acquiring information that preparation for a contrast radiography of applying X-rays from a plurality of angles onto the subject P having a contrast agent injected thereto by the contrast agent injector 200 is not yet completed, the top plate driving device 14 moves the top plate 11 to a preparation position p2 for preparing for the contrast radiography.SELECTED DRAWING: Figure 7

Description

  Embodiments described herein relate generally to an X-ray CT apparatus that performs contrast imaging.

  An X-ray CT apparatus includes a contrast examination in which a contrast medium is injected into a subject by a contrast medium injector and imaging is performed. When contrast examination is performed with an X-ray CT apparatus, it is performed in combination with simple imaging for positioning. In this contrast examination, preparation for contrast imaging such as securing a route for injecting a contrast medium between the subject and the contrast medium injector is often performed after simple imaging is completed.

  However, since the top plate is automatically moved to the position for performing contrast imaging after the completion of simple imaging, when preparing for contrast imaging, the top plate is moved to a position where preparation for contrast imaging is easy. Operation to move is necessary, and burdens a busy operator during inspection.

Japanese Patent Laying-Open No. 2015-165887

  The problem to be solved by the present invention is to provide an X-ray CT apparatus capable of reducing the burden on the operator for contrast examination.

  The X-ray CT apparatus according to the embodiment includes an X-ray tube that irradiates an object placed on a top plate with X-rays, and an X-ray that is irradiated by the X-ray tube and transmitted through the object. The preparation of the contrast imaging is obtained when the preparation of contrast imaging in which X-rays are irradiated from the X-ray tube from a plurality of directions to the subject into which the contrast medium is injected by the line detector and the contrast agent injector is acquired. A top plate driving unit that moves the top plate to a preparation position for performing the above.

1 is a block diagram showing a configuration of an X-ray CT apparatus according to an embodiment. The block diagram which shows an example of a structure of the contrast agent injector which concerns on embodiment. The flowchart which shows operation | movement of the X-ray CT system which concerns on embodiment. The figure which shows an example of the posture of the subject mounted on the top plate which concerns on embodiment. The figure which shows an example of the simple imaging | photography position of the top plate which concerns on embodiment. The figure for demonstrating an example of the calculation of the moving direction and distance of the top plate which concerns on embodiment. The figure which shows an example of the preparation position of the top plate which concerns on embodiment. The figure which shows an example of the contrast imaging position of the top plate which concerns on embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of an X-ray CT system according to the embodiment. This X-ray CT system includes an X-ray CT apparatus 100 and a contrast medium injector 200.

  The X-ray CT apparatus 100 includes a bed apparatus 10 on which the subject P is placed and moved, a gantry apparatus 20 on which the subject P is irradiated with X-rays, and a console apparatus 30 on which image data is generated. And. The X-ray CT apparatus 100 performs simple imaging for positioning in the case of contrast examination combining simple imaging and contrast imaging, and after the simple imaging is completed, the contrast agent is injected by the contrast agent injector 200. Contrast imaging is performed by irradiating the subject P with X-rays from a plurality of angles.

  The couch device 10 includes a top plate 11, a support frame 12, a base 13, and a top plate driving device 14. The top plate 11 is formed in a rectangular plate shape, on which the subject P is placed. The support frame 12 is a frame that supports the top plate 11 so as to be movable in the longitudinal direction. The base 13 is a housing that supports the support frame 12 so as to be movable in the vertical direction. The top plate driving device 14 includes a motor that moves the top plate 11 in the longitudinal direction and a motor that drives the support frame 12 and moves the top plate 11 in the vertical direction. In the following, the short direction of the top plate 11 is defined as the X-axis direction, the vertical direction perpendicular to the X-axis direction is defined as the Y-axis direction, and the longitudinal direction of the top plate 11 which is the direction orthogonal to the X-axis direction and the Y-axis direction is defined as The Z axis direction.

  In contrast examination, the top board driving device 14 moves the top board 11 on which the subject P is placed to a position where simple imaging is performed (simple imaging position). It moves to a position for preparing contrast imaging (preparation position) or a position for performing contrast imaging (contrast imaging position), such as the connection between the injector 200 and the subject P and the description of contrast imaging for the subject P. The top plate drive device 14 is an example of a top plate drive unit.

  The gantry device 20 is disposed in the Z-axis direction of the bed device 10, and includes an X-ray tube 21, an X-ray detector 22, a high voltage device 23, a rotating frame 24, a rotation driving device 25, and a data collecting device 26. It has.

  The X-ray tube 21 is rotatably disposed opposite the X-ray detector 22 and includes, for example, a vacuum tube that radiates thermal electrons from the cathode toward the anode when a high voltage is applied from the high voltage device 23. The X-ray tube 21 includes a plurality of X-rays irradiated from a certain direction and rotating around the subject P with respect to the subject P moved between the X-ray detector 22 by the bed apparatus 10. X-ray irradiation from the direction is performed.

  The X-ray detector 22 includes, for example, a plurality of X-ray detection elements arranged in a grid pattern in an arcuate channel direction indicated by an arrow centered on the focal point of the X-ray tube 21 and a slice direction parallel to the Z axis. It has. Then, the X-ray detector 22 detects X-rays irradiated from the X-ray tube 21 and transmitted through the subject P, and outputs an electrical signal corresponding to the X-ray dose to the data collection device 26.

  The high voltage device 23 is composed of an electric circuit such as a transformer and a rectifier, and has a function of generating a high voltage to be applied to the X-ray tube 21 and the X-ray irradiated by the X-ray tube 21. The X-ray control device controls the output voltage. The high voltage device 23 applies a high voltage for simple imaging or contrast imaging to the X-ray tube 21. The high voltage device 23 is an example of a high voltage unit.

  The rotating frame 24 is an annular frame that rotatably supports the X-ray tube 21, the X-ray detector 22, the high voltage device 23, and the data collection device 26. The rotation drive device 25 includes a motor that drives the rotation frame 24 to rotate. Then, the rotation drive device 25 has an X-ray tube 21, an X-ray detector 22, a high voltage device 23, and a data collection device supported by the rotation frame 24 around a virtual axis passing through an isocenter C parallel to the Z axis. 26 is rotated in one direction. The rotation drive device 25 is an example of a rotation drive unit.

  The data collection device 26 includes an amplifier that performs amplification processing on an electric signal output from each X-ray detection element of the X-ray detector 22, an A / D converter that converts the amplified electric signal into a digital signal, and the like. Is done. Then, the data collection device 26 generates projection data of one view for each predetermined angle (view angle) by the rotation of the rotation frame 24, and generates projection data of a plurality of views by rotation corresponding to one scan of the rotation frame 24. collect. The data collection device 26 is an example of a data collection unit.

  The console device 30 is disposed apart from the bed device 10 and the gantry device 20, and includes a processing circuit 31, a storage device 32, a display device 33, an input device 34, and a communication device 35. Then, the console device 30 generates tomographic image data of the subject P and image data such as volume data based on the projection data collected by the gantry device 20. The console device 30 is an example of a console unit.

  The processing circuit 31 includes a top panel control function 311, a scan control function 312, an image processing function 313, a display control function 316, and a system control function 317. The processing circuit 31 is an example of a processing unit.

  The top board control function 311 controls the top board driving device 14 of the bed apparatus 10. Then, the top board control function 311 acquires the position information of the top board 11 from the top board driving device 14 by moving the top board 11 in the vertical direction or the longitudinal direction. The top plate control function 311 is an example of a top plate control unit.

  The scan control function 312 controls various operations such as X-ray scanning, such as irradiating the X-ray tube 21 with X-rays while rotating the rotating frame 24 by the high-voltage device 23 or the rotation driving device 25. The scan control function 312 is an example of a scan control unit.

  The image processing function 313 includes a preprocessing function 314 and a reconstruction processing function 315. Then, the image processing function 313 generates image data based on the projection data of a plurality of views collected by the data collection device 26. The image processing function 313 is an example of an image processing unit.

  The preprocessing function 314 performs preprocessing such as offset correction, logarithmic conversion processing, and sensitivity correction on each projection data collected by the data collection device 26. The preprocessing function 314 is an example of a preprocessing unit.

  The reconstruction processing function 315 generates tomographic image data and volume data corresponding to the tomographic plane of the subject P from the preprocessed projection data of a plurality of views. The reconstruction processing function 315 generates contrast image data from projection data of a plurality of views generated by X-ray irradiation on the subject P into which a contrast agent has been injected and preprocessed. The reconstruction processing function 315 is an example of a reconstruction processing unit.

  The display control function 316 performs various controls related to image display. Then, control is performed to display each image data such as tomographic image data, volume data, and contrast image data generated by the image processing function 313 on the display device 33. The display control function 316 is an example of a display control unit.

  The system control function 317 controls the operations of the bed apparatus 10, the gantry apparatus 20, and the console apparatus 30, and controls the X-ray CT apparatus 100 as a whole. The system control function 317 is an example of a system control unit.

  The storage device 32 includes, for example, a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, and the like. The storage device 32 stores each projection data collected by the gantry device 20, each projection data preprocessed by the preprocessing function 314, tomographic image data and volume data generated by the image processing function 313, and the like. The storage device 32 is an example of a storage unit.

  The display device 33 includes a display circuit, a video memory, a CRT, a liquid crystal display, and the like. The display device 33 displays image data such as tomographic image data, volume data, and contrast image data generated by the image processing function 313. The display device 33 is an example of a display unit.

  The input device 34 includes, for example, a keyboard, a mouse, a trackball, a joystick, and the like. Then, in order to obtain each image data, the input device 34 includes a diagnosis target region (imaging region) of the subject P, a scan method, the number of sheets, a slice interval, a tube current and a tube voltage, an effective visual field region (FOV), and the like. Input to set various shooting conditions. Further, the input device 34 performs an input for moving the top 11 to a simple imaging position or the like where the subject P can be irradiated with X-rays. In addition, the input device 34 includes a switch, and inputs that the preparation for contrast imaging has not been completed or has been completed. The input device 34 is an example of an input unit. In addition, you may implement so that the switch which performs the preparation uncompleted or the preparation completion input of contrast imaging | photography may be arrange | positioned in the bed apparatus 10 or the gantry measure 20. FIG.

  The communication device 35 includes a transmission / reception circuit and the like, and communicates with the contrast medium injector 200 by serial communication or CAN (controller area network) communication. Then, the communication device 35 receives from the contrast agent injector 200 information that has not been prepared and that requires preparation for contrast imaging or information that indicates that preparation for contrast imaging has been completed and preparation for contrast imaging is possible.

  The processing functions of the top board control function 311, the scan control function 312, the image processing function 313, the display control function 316, and the system control function 317 performed by the processing circuit 31 are stored in the form of a program that can be realized by a computer in the storage device 32. Is saved. The processing circuit 31 is a processor that realizes a processing function corresponding to each program by reading each program from the storage device 32 and executing the program. In other words, the processing circuit 31 in a state where each program is read has each processing function shown in the processing circuit 31 of FIG.

  In FIG. 1, the processing functions of the top panel control function 311, the scan control function 312, the image processing function 313, the display control function 316, and the system control function 317 are realized by a single processing circuit 31. However, the processing functions may be realized by a plurality of processors realizing each program.

  FIG. 2 is a block diagram showing an example of the configuration of the contrast medium injector 200. The contrast agent injector 200 is a device that injects a contrast agent into the subject P placed on the top plate 11 of the bed apparatus 10, and includes an injection device 201, an input device 211, a communication device 221, and a control device. 231.

  The injection device 201 includes a puncture needle to be punctured by the subject P, a tube having one end connected to the puncture needle, a pump connected to the other end of the tube, and a power source for driving the pump. Motor.

  The input device 211 includes, for example, a switch. Then, the input device 211 performs an input indicating that preparation for contrast imaging has not been completed or has been completed by an operator's operation. In addition, you may implement so that the input device 211 may be arrange | positioned at the bed apparatus 10 or the gantry apparatus 20. FIG.

  The communication device 221 includes a transmission / reception circuit and the like, and performs communication with the communication device 35 of the X-ray CT apparatus 100 by, for example, serial communication or CAN (Controller Area Network) communication. Then, the communication device 221 transmits to the communication device 35 information indicating that the preparation has not been completed or has been completed, which is input from the input device 211.

  The control device 231 includes a CPU and a storage circuit, and controls the injection device 201, the input device 211, and the communication device 221.

  Note that the control device 231 recognizes positional information of the contrast medium injector 200 with respect to the bed apparatus 10 and the gantry apparatus 20, and contrasts together with unprepared information from the communication apparatus 221 in response to an unprepared input from the input apparatus 211. You may implement so that the communication apparatus 35 may transmit the positional information on the chemical | medical agent injector 200. FIG.

  Hereinafter, an example of the operation of the X-ray CT system in the contrast examination will be described with reference to FIGS. 1 to 8.

  FIG. 3 is a flowchart showing the operation of the X-ray CT system.

  Patient ID such as name and height for identifying the subject P, irradiation conditions such as tube voltage and tube current for performing simple imaging and contrast imaging, imaging region of the subject P, subject placed on the top 11 Input of various examination information related to the contrast examination such as the posture of the specimen P, position information in the Z-axis direction of the contrast medium injector 200 with respect to the bed apparatus 10 and the gantry apparatus 20, and the puncture position of the subject P that punctures the contrast medium injector 200 When performed from the input device 34, the X-ray CT system starts operation (step S1).

  The system control function 317 instructs a contrast examination to each unit of the bed apparatus 10, the gantry apparatus 20, and the console apparatus 30.

  FIG. 4 is a view showing an example of the posture of the subject P placed on the top board 11. The subject P is placed on the top plate 11 with his head facing toward the gantry device 20 and his upper arm assembled above the head. The imaging region of the subject P is the heart, and the puncture position of the subject P punctured by the contrast medium injector 200 is the upper arm in a state of being assembled over the head.

  In addition to the posture shown in FIG. 4, the posture to be placed on the back with the head facing the gantry device 20 side and the upper arm lowered on the top plate 11, the upper arm facing the gantry device 20 side. There are a plurality of postures such as a posture placed on the back in a state of being lowered on the plate 11. The puncture position of the contrast medium injector 200 includes an upper arm and a lower limb that are lowered on the top board 11 in addition to the upper arm that is assembled over the head.

  When the simple imaging position is input from the input device 34, the top board driving device 14 moves the top board 11 in the direction of the arrow L1 parallel to the Z axis, and the heart of the subject P is almost as shown in FIG. It stops at the simple photographing position p1 at which it becomes the isocenter C (step S2 in FIG. 3).

  When a simple imaging start input is performed from the input device 34, the gantry device 20 generates projection data by irradiating the subject P on the top 11 with X-rays. The image processing function 313 generates simple image data based on the projection data generated by the gantry device 20, and the display device 33 displays the simple image data generated by the image processing function 313 (step S3 in FIG. 3).

  Here, as simple imaging, the image processing function 313 generates scano image data as simple image data by irradiating the subject P from a certain direction with the X-ray tube 21 stopped at a certain angle, for example. Then, the display device 33 displays the scanogram data generated by the image processing function 313. The imaging position of the subject P is determined by an input for setting the contrast imaging position of the subject P on the scano image data from the input device 34.

  Before the X-ray irradiation is stopped or after the X-ray irradiation is stopped and the simple imaging is finished, the operator presses the switch of the input device 211 of the contrast agent injector 200, so that the preparation of contrast imaging is not performed from the input device 211. When the completion input is performed, the communication device 221 transmits information indicating that preparation for contrast imaging has not been completed to the communication device 35 of the console device 30. The system control function 317 obtains information indicating that preparation for contrast imaging has not been completed by reception of the communication device 35 (step S4 in FIG. 3). It should be noted that the input device 34 may be pressed so that an input indicating that preparation for contrast imaging has not been completed is performed by pressing a switch of the input device 34. In this case, the system control function 317 can acquire information indicating that preparation for contrast imaging has not been completed from the input device 34.

  Note that before the X-ray irradiation is stopped or after the X-ray irradiation is stopped and the simple imaging is completed, by pressing the switch of the input device 211, the input device 211 is ready for contrast imaging. In step S4, the system control function 317 acquires information about the completion of preparation for contrast imaging, and proceeds from step S4 to step S8. In step S4, when an input indicating completion of preparation for contrast imaging is performed from the input device 34, the system control function 317 acquires information on completion of preparation for contrast imaging, and the process proceeds to step S8.

  The top panel control function 311 shifts from the simple imaging position p1 to the preparation position based on the preset position information of the contrast medium injector 200, information on the simple imaging position of the top board 11, and examination information input from the input device 34. The moving direction and distance of the top plate 11 to be moved are calculated (step S5 in FIG. 3).

  FIG. 6 is a diagram for explaining an example of calculation of the moving direction and distance of the top plate 11.

  The storage device 32 stores in advance a table indicating the relationship between, for example, each height obtained statistically and the distance from the heart at this height to the upper arm built on the head at the puncture position. The top board control function 311 includes the height, body position and puncture position included in the examination information input from the input device 34, the position information of the contrast medium injector 200, the information on the simple imaging position of the top board 11, and the storage device 32. The preparation position is calculated from the information stored in the table.

  Here, the contrast agent injector 200 is located at a distance D1 in the L1 direction from the center axis indicated by the broken line passing through the isocenter C of the gantry device 20. Note that the contrast medium injector 200 may be located in a direction opposite to the L1 direction from the central axis indicated by a broken line passing through the isocenter C of the gantry device 20.

  Further, the distance from the table stored in the storage device 32 to the distance from the table stored in the storage device 32 is the distance from the heart, which is the imaging region of the subject P, to the upper arm assembled above the head that is the puncture position. The direction of movement of the top 11 from the simple imaging position p1 is a direction in which the puncture position of the subject P is away from the gantry device 20 and approaches the contrast agent injector 200 so that the subject P can be easily punctured with the contrast agent injector 200. It becomes the L1 direction which is. Further, the distance by which the top 11 is moved from the simple photographing position p1 is a distance D3 obtained by subtracting the distance D2 from the distance D1.

  After step S5 in FIG. 3, the top plate driving device 14 moves the top plate 11 at the simple photographing position p1 by the distance D3 in the L1 direction and stops it at the preparation position p2 as shown in FIG. 7 (step in FIG. 3). S6).

  As described above, the top plate 11 at the simple imaging position p1 is prepared in accordance with the position of the contrast medium injector 200, the puncture position and the body position of the subject P only by a simple operation of, for example, pressing a switch from the input device 211. It can be moved to p2. This can reduce the burden on a busy operator during the contrast examination.

  When preparation for contrast imaging such as puncture of the contrast medium injector 200 to the subject P and explanation of contrast imaging is completed and preparation completion of contrast imaging is input from the input device 211, the communication device 221 enters the communication device 35. Information on completion of preparation for contrast imaging is transmitted. The system control function 317 acquires information on completion of preparation for contrast imaging by reception of the communication device 35 (step S7 in FIG. 3).

  Note that the system control function 317 can also acquire information on the completion of preparation for contrast imaging by inputting the completion of preparation for contrast imaging from the input device 34.

  The top board control function 311 moves and moves the top board 11 to be moved from the preparation position p2 to the contrast imaging position based on the information on the contrast imaging position set in advance and the position information on the preparation position p2 calculated in step S3. Calculate As shown in FIG. 8, the top board driving device 14 moves the top board 11 at the preparation position p2 in the direction of the arrow L2 opposite to the L1 direction, and stops at the contrast imaging position p3 that is the imaging position of the subject P. (Step S8 in FIG. 3).

  When an input for starting contrast imaging is performed from the input device 34, the contrast agent injector 200 injects a contrast agent into the subject P in accordance with an instruction from the system control function 317 via the communication devices 35 and 221. The gantry device 20 generates projection data by, for example, irradiating the subject P on the top plate, which has passed a predetermined time after the injection of the contrast medium, with X-rays from a plurality of directions. The image processing function 313 generates contrast image data based on the projection data generated by the gantry device 20, and the display device 33 displays the contrast image data generated by the image processing function 313 (step S9 in FIG. 3).

  When X-ray irradiation of the gantry device 20 is stopped and contrast image data is displayed on the display device 33, the X-ray CT system ends its operation (step S10 in FIG. 3).

  It should be noted that the rotation drive device 25 is rotated in advance in preparation for contrast imaging until the preparation of contrast imaging is performed and the top plate 11 is moved to the contrast imaging position p3 after acquiring information that is not ready for contrast imaging. The frame 24 is set up and the high voltage device 23 is set up the X-ray tube 21, and further at least one of the X-ray detector 22 and the data acquisition device 26 is set up. Control of each unit for contrast imaging may be performed by the scan control function 312. As a result, it is possible to shorten the time from the completion of preparation for contrast imaging to the start of X-ray irradiation by contrast imaging.

  In addition, the rotation drive device 25 stops the rotation of the rotating frame 24 or the rotation of the rotating frame 24 from the time of contrast imaging until the contrast imaging is started after the information that the preparation for contrast imaging is not completed is started. Alternatively, the scan control function 312 may execute the control for decelerating. Thereby, since the operating sound of the gantry device 20 can be suppressed, it is possible to easily explain contrast imaging on the subject P when preparing for contrast imaging.

  Further, when the information about the completion of preparation for contrast imaging is acquired, the contrast agent is injected into the subject P by the contrast agent injector 200 in response to the input of the start of contrast imaging from the input device 34, and the injection of the contrast agent is started. When contrast imaging is started by starting X-ray irradiation on the subject P on the top plate 11 at the contrast imaging position p3 when a predetermined time has elapsed, the top 11 moves from the preparation position p2 to the contrast imaging position p3. If the time required for the imaging is shorter than the predetermined time, the movement of the top 11 at the preparation position p2 to the contrast imaging position p3 is started after the injection of the contrast medium is started, and the contrast imaging position is started by the start of X-ray irradiation. When the time required for moving the top 11 from the preparation position p2 to the contrast imaging position p3 is equal to or longer than a predetermined time, the top 11 is moved to p3 and before the injection of the contrast agent is started. Of the top plate 11 To start moving to the shadow imaging position p3, it may be performed so as to move the top plate 11 until the contrast imaging position p3 to the start of the X-ray irradiation. Thus, until the X-ray irradiation is started by contrast imaging, the subject P is stopped at a position where the eye reaches the operator or a position where the operator can easily drop it from the top plate 11 in an emergency such as a side effect. Thus, it is possible to quickly cope with an abnormality in the subject P such as an allergic reaction to the contrast medium.

  According to the embodiment described above, the top plate 11 at the simple imaging position p1 is moved to the position of the contrast medium injector 200, the puncture position and the body position of the subject P only by a simple operation of pressing the switch from the input device 211. Together, it can be moved to the preparation position p2. This can reduce the burden on a busy operator during the contrast examination.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

11 Top plate 14 Top plate drive device 21 X-ray tube 22 X-ray detector 313 Image processing function

Claims (9)

An X-ray tube that irradiates the subject placed on the top board with X-rays;
An X-ray detector for detecting X-rays irradiated by the X-ray tube and transmitted through the subject;
When information on unconfirmed preparation for contrast imaging for irradiating X-rays from the X-ray tube from a plurality of directions to the subject into which the contrast medium has been injected by the contrast agent injector is acquired, the preparation position for preparing the contrast imaging is obtained. An X-ray CT apparatus comprising: a top plate driving unit that moves the top plate.   The top plate driving unit moves from the simple imaging position where the simple imaging is performed to the preparation position after the X-ray irradiation by the simple imaging for determining the position of the subject to perform the contrast imaging is completed. The X-ray CT apparatus according to claim 1, wherein the X-ray CT apparatus moves on a plate. Position information of the contrast medium injector set in advance, information on the body position of the subject placed on the top board, information on the puncture position of the subject that punctures the contrast medium injector, and the simple imaging position Based on the information, having a top board control unit that calculates the moving direction and distance of the top board to be moved from the simple photographing position to the preparation position,
3. The top plate driving unit stops the top plate at the simple imaging position by moving the distance in a direction in which the puncture position moves away from the X-ray tube and approaches the contrast medium injector, and stops at the preparation position. X-ray CT apparatus described in 1.   4. The X-ray CT according to claim 1, wherein the top plate driving unit moves the top plate to a contrast imaging position where the contrast imaging is performed when the information on completion of preparation for the contrast imaging is acquired. apparatus. The top plate control unit calculates a moving direction and a distance of the top plate to be moved from the preparation position to the contrast imaging position based on information on the contrast imaging position set in advance,
The said top-plate drive part moves the said distance in the direction opposite to the moving direction from the said simple imaging position to the said preparation position, and stops the said top-plate of the said preparation position in the said contrast imaging position. The X-ray CT apparatus described. A high voltage section for generating a high voltage applied to the X-ray tube;
A rotation drive unit that rotates a rotating frame that supports the X-ray tube during the contrast imaging;
The high voltage unit is configured to cause the rotation driving unit to rotate the rotating frame to perform setup until the top plate moves to the contrast imaging position after acquiring information that is not ready for the contrast imaging. The X-ray CT apparatus according to claim 4, further comprising: a scan control unit that causes the X-ray tube to be set up. A data collection unit that collects signals detected by the X-ray detector and generates projection data; and the scan control unit acquires information that is not ready for contrast imaging, and then moves to the contrast imaging position. The X-ray CT apparatus according to claim 6, wherein at least one of setup of the X-ray detector or setup of the data acquisition unit is performed until the top plate moves. A rotation drive unit that rotates a rotating frame that supports the X-ray tube during the contrast imaging;
The rotation drive unit stops the rotation of the rotating frame or the rotation of the rotating frame during the contrast imaging from the acquisition of the information that is not ready for the contrast imaging to the start of the contrast imaging. The X-ray CT apparatus according to claim 4, further comprising a scan control unit that further decelerates the scan control unit. The X-ray tube starts X-ray irradiation when a predetermined time has elapsed since the injection of the contrast medium into the subject was started by the contrast medium injector,
The top plate drive unit is
When the time required for moving the top plate from the preparation position to the contrast imaging position is shorter than the predetermined time, the contrast imaging position of the top plate at the preparation position after the injection of the contrast agent is started Moving the top plate to the contrast imaging position by the start of X-ray irradiation by the X-ray tube,
When the time required for the top plate to move from the preparation position to the contrast imaging position is equal to or longer than the predetermined time, the contrast imaging of the top plate at the preparation position before the injection of the contrast agent is started. The X-ray CT apparatus according to claim 4, wherein the X-ray CT apparatus starts moving to a position and moves the top to the contrast imaging position before starting X-ray irradiation by the X-ray tube.