JP6804218B2 - X-ray computed tomography equipment and sleeper equipment - Google Patents

Description

Embodiments of the present invention relate to an X-ray computed tomography apparatus and a sleeper apparatus.

In order to obtain a high-quality CT image, it is required to reduce the bending and vibration of the top plate. In order to realize this, it is conceivable to bring the sleeper frame that slidably supports the top plate as close as possible to the gantry. However, the closer the sleeper frame is to the mount, the higher the risk that the tilted mount will interfere with the sleeper frame. Interference can be avoided by setting restrictions on the tilt angle, the position of the sleeper frame, and the like, but the ability of the X-ray computed tomography apparatus provided with the sleeper cannot be maximized.

Japanese Unexamined Patent Publication No. 2013-123595 Japanese Unexamined Patent Publication No. 7-16221 Jikkenhei 6-48606 Jikkai Sho 61-103104

An object of the embodiment is to provide an X-ray computed tomography device and a bed device capable of increasing the degree of freedom in positioning the pedestal and the bed while reducing the bending and vibration of the top plate.

The X-ray computed tomography apparatus according to the present embodiment has a pedestal equipped with an X-ray tube and an X-ray detector, a top plate on which a subject is placed, and the top plate can be moved along a long axis. It is provided with a sleeper having a first support portion for supporting the top plate, and a control unit for moving the top plate and the first support portion so as to fix the position of the top plate with respect to the pedestal.

FIG. 1 is a diagram showing a configuration of an X-ray computed tomography apparatus according to the present embodiment. FIG. 2 is a diagram schematically showing the appearance of the pedestal and the bed according to the present embodiment. FIG. 3 is a diagram schematically showing a side surface of the bed according to the present embodiment. FIG. 4 is a perspective view of the lower frame, the X-link, and the base of the bed according to the present embodiment. FIG. 5 is a diagram showing the protrusion of the bed according to the present embodiment. FIG. 6 is a side view schematically showing the inside of the gantry according to the present embodiment. FIG. 7 is a diagram for explaining the interference between the pedestal and the bed according to the present embodiment, and is a diagram schematically showing a vertical cross section of the pedestal main body, the top plate, and the upper frame of the pedestal. FIG. 8 is a diagram showing a configuration example of the gantry / sleeper drive system and the gantry control circuit according to the present embodiment. FIG. 9 is a diagram for explaining the interference determination function of the gantry control circuit of FIG. FIG. 10 is another diagram for explaining the interference determination function of the gantry control circuit of FIG. FIG. 11 is a diagram showing the operation of the top plate and the top plate support frame in the extended mode, and is a diagram showing the pedestal body and the bed before and after the interference avoidance operation. FIG. 12 is a diagram showing a typical flow of tilt operation control performed under the control of the gantry control circuit according to the first embodiment. FIG. 13 is a diagram schematically showing the operation of the bed and the pedestal body according to the first embodiment. FIG. 14 is a diagram showing a typical flow of tilt operation control performed under the control of the gantry control circuit according to the second embodiment. FIG. 15 is a diagram schematically showing the operation of the bed and the pedestal body according to the second embodiment. FIG. 16 is a diagram schematically showing the operation of the bed and the pedestal body according to the modified example 8.

Hereinafter, the X-ray computed tomography apparatus and the sleeper apparatus according to the present embodiment will be described with reference to the drawings.

The sleeper device according to the present embodiment is for medical imaging used in medical image diagnostic devices such as an X-ray computed tomography device, an X-ray diagnostic device, a PET (positron emission tomography) device, and a SPECT (single photon emission computed tomography) device. It is a sleeper device. The sleeper device according to the present embodiment is not limited to the single modality device as described above, and may be used for a multi-modality device such as a PET / CT device, a SPECT / CT device, and an IVR (interventional radiology) / CT. Hereinafter, the sleeper device according to the present embodiment shall be provided in the X-ray computed tomography device.

FIG. 1 is a diagram showing a configuration of an X-ray computed tomography apparatus according to the present embodiment. As shown in FIG. 1, as shown in FIG. 1, the X-ray computed tomography apparatus according to the present embodiment has a gantry 10 and a console 100. For example, the gantry 10 is installed in the CT examination room, and the console 100 is installed in the control room adjacent to the CT examination room. The gantry 10 and the console 100 are connected so as to be able to communicate with each other. The gantry 10 is equipped with a scanning mechanism for performing an X-ray CT scan of the subject O. The console 100 is a computer that controls the gantry 10.

As shown in FIG. 1, the gantry 10 has a substantially cylindrical rotating frame 11 in which an opening forming a field of view is formed. As shown in FIG. 1, the rotating frame 11 is provided with an X-ray tube 13 and an X-ray detector 15 arranged so as to face each other with an opening in between. The rotating frame 11 is a metal frame formed in a ring shape by a metal such as aluminum. As will be described later, the gantry 10 has a main frame made of a metal such as aluminum. The rotary frame 11 is rotatably supported by the main frame around the central axis AR via bearings and the like. An annular electrode (not shown) is provided at a contact portion of the main frame with the rotating frame 11. A conductive slider (not shown) is attached to the contact portion so as to make sliding contact with the annular electrode. Various devices such as an X-ray detector 15 and a high voltage generator 17 mounted on the rotating frame 11 with electric power from a power supply device (not shown) housed in the gantry 10 via the annular electrode and the slider. Is supplied to.

The X-ray tube 13 is connected to the high voltage generator 17. The high voltage generator 17 is attached to, for example, a rotating frame 11. The high voltage generator 17 generates a high voltage to be applied to the X-ray tube 13 under the control of the gantry control circuit 33 from the electric power supplied from the gantry power supply device (not shown) via the annular electrode and the slider. The filament heating current is supplied. The high voltage generator 17 and the X-ray tube 13 are connected via a high voltage cable (not shown). The high voltage generated by the high voltage generator 17 is applied to the X-ray tube 13 via the high voltage cable. Further, the filament heating current generated by the high voltage generator 17 is applied to the X-ray tube 13 via the high voltage cable.

The rotating frame 11 receives power from the rotation driving device 21 and rotates around the central axis AR at a constant angular velocity. Any motor such as a direct drive motor or a servo motor is used as the rotation drive device 21. The rotation drive device 21 is housed in, for example, a gantry 10. The rotation drive device 21 receives a drive signal from the gantry control circuit 33 and generates power for rotating the rotation frame 11.

A FOV (field of view) is set in the opening (bore) of the rotating frame 11. A top plate supported by the sleeper 23 is inserted into the opening of the rotating frame 11. Subject O is placed on the top plate. The sleeper 23 is, for example, a two-stage slide type. The sleeper 23 freely moves the top plate by receiving power from the pedestal / sleeper drive system 25. Details of the sleeper 23 and the gantry / sleeper drive system 25 will be described later. The top plate is positioned so that the imaging site of the placed subject O is included in the FOV.

The gantry / sleeper drive system 25 includes a drive device for moving the gantry 10 such as tilting and slew of the gantry 10 and a drive device for moving the sleeper 23. The gantry / sleeper drive system 25 receives a drive signal from the gantry control circuit 33 to generate power. Details of the gantry / sleeper drive system 25 will be described later.

The X-ray detector 15 detects the X-rays generated from the X-ray tube 13. Specifically, the X-ray detector 15 has a plurality of detector elements arranged on a two-dimensional curved surface. Each detector element has a scintillator and a photoelectric conversion element. A scintillator is a substance that converts X-rays into fluorescence. The scintillator converts the incident X-rays into a number of fluorescent photons according to the intensity of the incident X-rays. A photoelectric conversion element is a circuit element that amplifies fluorescence and converts it into an electric signal. As the photoelectric conversion element, for example, a photomultiplier tube, a photodiode, or the like is used. The detector element may be an indirect detection type that detects after converting X-rays into light as described above, or a direct conversion type that directly converts X-rays into an electric signal. As the direct detection type detector pixel, for example, a type including a semiconductor diode in which electrodes are attached to both ends of the semiconductor can be applied.

A data acquisition circuit 27 is connected to the X-ray detector 15. The data collection circuit 27 collects data (hereinafter, referred to as raw data) corresponding to the intensity of X-rays detected by the X-ray detector 15 from the X-ray detector 15 for each view. Specifically, the data acquisition circuit 27 has, for example, an integrator circuit (not shown) and an A / D converter (not shown) for each detector element. The integrator circuit integrates the electrical signal from the detector element for each view. The A / D converter converts the integrated electrical signal from an analog signal to a digital signal (raw data). This collects raw data for each view. Raw data is a set of digital values indicating the intensity of X-rays identified by the channel number, column number, and view number indicating the collected view of the detector element from which it was generated. The raw data is supplied to the console 100 via, for example, a non-contact data transmission device (not shown) housed in the gantry 10. In addition, other circuit elements such as a preamplifier and an IV converter may be mounted on the data acquisition circuit 27. The data acquisition circuit 27 has a semiconductor integrated circuit such as an ASIC (Application Specific Integrated Circuit), and a circuit element such as the integrator circuit or the A / D converter is mounted on the semiconductor integrated circuit.

The display circuit 29 displays various information such as the geometric arrangement of the sleeper 23 and the gantry 10 and scanning conditions. Specifically, the display circuit 29 includes a display interface circuit and a display device. The display interface circuit converts data representing a display target into a video signal. The display signal is supplied to the display device. The display device is provided on the surface of the gantry 10. The display device displays a video signal representing the display target. As the display device, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used.

The input circuit 31 inputs various commands from the user regarding the movement of the sleeper 23 and the gantry 10. Specifically, the input circuit 31 has an input device and an input interface circuit. The input device receives various commands from the user. As an input device, an operation panel, various switches, and the like can be used. The input interface circuit supplies the output signal from the input device to the gantry control circuit 33 via the bus.

The gantry control circuit 33 includes a high voltage generator 17, a rotation drive device 21, a gantry / sleeper drive system 25, and a data acquisition circuit 27 in order to execute an X-ray CT scan according to the imaging conditions from the system control circuit 113 of the console 100. Control synchronously. Further, the gantry control circuit 33 controls the gantry / sleeper drive system 25, and moves the gantry 10 and the berth 23 in conjunction with each other in order to realize positioning of the gantry 10 and the berth 23 with less bending and vibration of the top plate. Let me. As hardware resources, the gantry control circuit 33 includes a processing unit (processor) such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit) and a storage device (a storage device) such as a ROM (Read Only Memory) and a RAM (Random Access Memory). Memory) and. Further, the gantry control circuit 33 includes an ASIC, a field programmable logic device (FPGA), another complex programmable logic device (CPLD), and a simple programmable logic device (Simple Programmable Logic Device). : SPLD) may be realized. The details of the gantry control circuit 33 will be described later.

As shown in FIG. 1, the console 100 includes a preprocessing circuit 101, a reconstruction circuit 103, an image processing circuit 105, a display circuit 107, an input circuit 109, a main memory circuit 111, and a system control circuit 113. Data communication between the preprocessing circuit 101, the reconstruction circuit 103, the image processing circuit 105, the display circuit 107, the input circuit 109, the main memory circuit 111, and the system control circuit 113 is performed via a bus.

The preprocessing circuit 101 has a processor such as a GPU (Graphics Processing Unit) and a storage device such as a ROM or RAM as hardware resources. The preprocessing circuit 101 performs preprocessing such as logarithmic conversion on the raw data transmitted from the gantry 10. The raw data after preprocessing is also called projection data.

The reconstruction circuit 103 has a processor such as a CPU, MPU, or GPU, and a memory such as a ROM or RAM as hardware resources. The reconstruction circuit 103 generates a CT image representing the spatial distribution of CT values for subject O based on the raw data after preprocessing. Image reconstruction algorithms include analytical image reconstruction methods such as the FBP (filtered back projection) method and CBP (convolution back projection) method, the ML-EM (maximum likelihood expectation maximization) method, and the OS-EM (ordered subset). An existing image reconstruction algorithm such as a statistical image reconstruction method such as the expectation maximization method may be used.

The preprocessing circuit 101 and the reconstruction circuit 103 may be incorporated into a single hardware resource.

The image processing circuit 105 performs various image processing on the CT image reconstructed by the reconstructing circuit 103. For example, the image processing circuit 105 performs three-dimensional image processing such as volume rendering, surface volume rendering, image value projection processing, MPR (Multi-Planer Reconstruction) processing, and CPR (Curved MPR) processing on the CT image for display. Generate an image. The image processing circuit 105 has a processor such as a CPU, MPU, and GPU and a memory such as a ROM and RAM as hardware resources. Further, the image processing circuit 105 may be realized by an ASIC, FPGA, CPLD, or SPLD.

The display circuit 107 displays various data such as a two-dimensional CT image and a display image. Specifically, the display circuit 107 includes a display interface circuit and a display device. The display interface circuit converts data representing a display target into a video signal. The display signal is supplied to the display device. The display device displays a video signal representing the display target. As the display device, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used.

The input circuit 109 inputs various commands from the user. Specifically, the input circuit 109 has an input device and an input interface circuit. The input device receives various commands from the user. As an input device, a keyboard, a mouse, various switches and the like can be used. The input interface circuit supplies the output signal from the input device to the system control circuit 113 via the bus.

The main storage circuit 111 is a storage device such as an HDD, an SSD, or an integrated circuit storage device that stores various information. Further, the main storage circuit 111 may be a drive device or the like that reads and writes various information to and from a portable storage medium such as a CD-ROM drive, a DVD drive, and a flash memory. For example, the main storage circuit 111 stores data of a CT image or a display image. Further, the main storage circuit 111 stores a control program and the like related to the X-ray CT scan according to the present embodiment.

The system control circuit 113 has a processor such as a CPU or MPU and a memory such as a ROM or RAM as hardware resources. Further, the system control circuit 113 may be realized by an ASIC, an FPGA, a CPLD, or a SPLD. The system control circuit 113 functions as the center of the X-ray computed tomography apparatus according to the present embodiment. Specifically, the system control circuit 113 reads out the control program stored in the main storage circuit 111, expands it on the memory, and controls each part of the X-ray computed tomography apparatus according to the expanded control program.

Next, the positional relationship between the gantry 10 and the sleeper 23 according to the present embodiment will be described with reference to FIG. FIG. 2 is a diagram schematically showing the appearance of the gantry 10 and the sleeper 23 according to the present embodiment. As shown in FIG. 2, the gantry 10 has a housing 43 in which a substantially cylindrical opening 41 is formed. The housing 43 houses a rotating frame 11 provided with an X-ray tube 13 and an X-ray detector 15 with an opening 41 interposed therebetween.

A sleeper 23 is installed in front of the gantry 10. The sleeper 23 is equipped with a top plate 51, a top plate support frame 53, and a support base 55. The top plate 51 is arranged so that the long axis A1 of the top plate 51 is parallel to the central axis AR of the opening 41. The top plate support frame 53 slidably supports the top plate 51 along the long axis A1 of the top plate 51. The support base 55 supports the top plate support frame 53 so as to be slidable along an axis parallel to the long axis A1 and to be raised and lowered along a vertical axis A2 vertically orthogonal to the long axis A1. The support base 55 has a cantilever support structure. That is, the support base 55 supports the top plate 51 and the top plate support frame 53 from only one side with respect to the long axis A1 direction. Here, the axis parallel to the long axis A1 is defined as the Z axis, and the axis parallel to the vertical axis A2 is defined as the Y axis. An axis orthogonal to the Z-axis and the Y-axis is defined as the X-axis. The XYZ coordinate system forms a Cartesian coordinate system. Hereinafter, the direction parallel to the long axis A1 of the top plate 51 will be referred to as the long axis direction or the Z direction, and the direction parallel to the vertical axis A2 will be referred to as the vertical direction or the Y direction. Further, the direction in which the sleeper 23 approaches the pedestal 10 is the + Z direction, the direction in which the sleeper 23 is away from the pedestal 10 is the −Z direction, the direction in which the sleeper 23 rises is the + Y direction, and the direction in which the sleeper 23 descends is the −Y direction. ..

Next, the structure of the bed 23 will be described. FIG. 3 is a diagram schematically showing a side surface of the sleeper 23 according to the present embodiment. The housing of the sleeper 23 is not shown in FIG. As shown in FIG. 3, the bed 23 is installed in front of the pedestal 10 (in the −Z direction). As shown in FIG. 3, the bed 23 has a top plate 51, a top plate support frame 53, and a support base 55. The subject is placed on the top plate 51. The top plate 51 is a flexible plate-like structure. The top plate 51 is made of a material having a relatively high X-ray transmittance, such as urethane foam or carbon.

The top plate 51 is slidably supported in the Z direction by the top plate support frame 53. The top plate support frame 53 has an upper frame 61 and a lower frame 63. The upper frame 61 supports the top plate 51 from below. The upper frame 61 may have any structure as long as the top plate 51 can be slid. For example, the upper frame 61 includes a sturdy frame-shaped frame (not shown) that supports the top plate 51, and a guide rail (not shown) that is provided on the frame-shaped frame and guides the top plate 51 in the Z direction. have. The upper frame 61 is provided with a drive device (hereinafter, referred to as an upper drive device) 253 that generates power for sliding the top plate 51 in the Z direction. The upper drive device 253 is realized by an existing motor such as a servo motor. The upper drive device 253 is driven by the control of the gantry control circuit 33.

The lower frame 63 supports the upper frame 61 from below. The lower frame 63 slidably supports the upper frame 61 in the Z direction. The lower frame 63 may have any structure as long as the upper frame 61 can be slid. For example, the lower frame 63 is realized by a ball screw. The lower frame 63 is provided with a drive device (hereinafter, referred to as a lower drive device) 255 that generates power for sliding the upper frame 61 in the Z direction. The lower drive device 255 is realized by an existing motor such as a servo motor. The lower drive device 255 is driven by the control of the gantry control circuit 33.

The support base 55 is installed on the floor surface. The support base 55 has a support structure capable of approaching or separating from the base 10 while raising or lowering the lower frame 63 in the Y direction. For example, the support base 55 has an X-link 65 and a base 67. The X link 65 is connected to the lower frame 63 and the base 67. The base 67 is provided with a drive device (hereinafter, referred to as an elevating drive device) 73 for generating power for raising and lowering the lower frame 63 in the Y direction by the X link 65. The elevating drive device 257 is realized by an existing motor such as a servo motor. The elevating drive device 257 is driven by the control of the gantry control circuit 33.

FIG. 4 is a perspective view of the lower frame 63, the X-link 65, and the base 67. As shown in FIG. 4, the lower frame 63 has a frame-shaped frame 631. The frame-shaped frame 631 is a metal frame having a rectangular shape extending in the Z direction. The frame-shaped frame 631 is provided with a ball screw 632. The ball screw 632 has a screw shaft 6321 and a slider 6323. A groove is formed in the ball screw 632 so that a plurality of hard balls for reducing friction can circulate between the screw shaft 6321 and the slider 6323. The screw shaft 6321 is provided on the frame-shaped frame 631 so as to extend in the Z direction. A slider 6323 is screwed onto the screw shaft 6321. The slider 6323 has a through hole through which the screw shaft 6321 penetrates, and the through hole is formed with a screw groove that meshes with a thread formed on the screw shaft 6321. An upper frame 61 (not shown in FIG. 4) is attached to the slider 6323. The frame-shaped frame 631 is provided with a guide rail 633 for guiding the slide of the slider 6323 in the Z direction. One end of the screw shaft 6321 is provided on the frame-shaped frame 631 so as to be rotatable around the axis. The screw shaft 6321 rotates about the axis in conjunction with the rotation of the drive shaft of the lower drive device 255. The slider 6323 slides along the axial direction (that is, the Z direction) of the screw shaft 6321 in conjunction with the rotation of the screw shaft 6321. The screw shaft 6321 may be provided with a stopper 636 that mechanically limits the movable range of the slider 6323.

The X link 65 has a pair of links 651 and links 652 that are pivotally supported in an X shape. The link 651 and the link 652 are provided so as to be rotatable around the fulcrum 75. Each of the link 651 and the link 652 is formed of, for example, a pair of metal plates having substantially the same length and having a plate-like shape. The end 656 of one link 652 on the base 67 side is fixed to the base 67. The end portion 656 may be fixed by, for example, a fastener. The other end 655 of the link 652 is fixed to the frame frame 631. More specifically, the end portion 655 is fixed to a trochanter 634 provided on a pair of frames relating to the long sides of the frame-shaped frame 631. The trochanter 634 is fixed to the guide rail 633 with fasteners or the like. As a result, the end portion 655 can be fixed to the frame-shaped frame 631.

The end 654 of the other link 651 on the base 67 side is slidably supported by the base 67 in the Z direction. Specifically, a lead screw 76 is inserted through the end portion 654. One end of the lead screw 76 is connected to the elevating drive device 257. The elevating drive device 257 is arranged on the base 67. A braking device 77 is attached to the other end of the lead screw 76. A nut 78 is attached to the lead screw 76 between the end 654 and the braking device 77. The nut 78 is a structure having a through hole formed with a thread groove to be screwed into the thread of the lead screw 76. The other end 653 of the link 651 is slidably supported by the frame-shaped frame 631 in the Z direction. Specifically, the other end 653 is fixed to a trochanter 635 provided on a pair of frames relating to the long sides of the frame-shaped frame 631. The trochanter 635 is slidably attached to the guide rail 633 in the Z direction. That is, the guide rail 633 provided on the frame-shaped frame 631 guides both the slide of the slider 6323 (that is, the upper frame 61) in the Z direction and the slide of the link 651 in the Z direction with one rail.

The lead screw 76 rotates around the axis in conjunction with the rotation of the elevating drive device 257 around the drive shaft. The nut 78 slides along the axis of the reed screw 76 in conjunction with the rotation of the reed screw 76, that is, in the Z direction. For example, when the lead screw 76 rotates in the forward direction, the nut 78 slides in the + Z direction, and when the lead screw 76 rotates in the opposite direction, the nut 78 slides in the −Z direction. The nut 78 slides in the + Z direction to press the link 651 in the + Z direction, and the frame-shaped frame 631 is raised in the + Y direction by narrowing the distance between the link 651 and the link 652 in the Z direction. The link 651 is released from the pressure in the + Z direction by sliding the nut 78 in the −Z direction, and the frame-shaped frame 631 is lowered in the −Y direction by increasing the distance between the link 651 and the link 652 in the Z direction.

Next, the protrusion of the two-stage slide type bed 23 according to the present embodiment will be described. FIG. 5 is a diagram showing the protrusion of the sleeper 23. In FIG. 5, the bed 23 arranged at the lower limit height is shown by a dotted line, and the bed 23 after ascending is shown by a solid line.

As shown in FIG. 5, the end portion of the lower frame 63 in the Z direction at the lower limit height, more specifically, the end portion of the frame-shaped frame 631 of the lower frame 63 in the Z direction is arranged at the position PE1 in the Z direction. It is assumed that As described above, the end 653 of the link 651 is slidably provided on the lower frame 63 in the Z direction, and the end 654 is slidably provided on the base 67 in the Z direction. The end 655 of the link 652 is fixed to the lower frame 63, and the end 656 is fixed to the base 67. Therefore, by pressing the link 651 with the nut 78, the end portion 655 moves along an arc PR having the end portion 656 as a fulcrum and a straight line connecting the end portion 655 and the end portion 656 as a radius. Before and after the movement, the position of the end portion 655 on the lower frame 63 and the position of the end portion 656 on the base 67 are immovable. Therefore, the end portion of the lower frame 63 in the Z direction protrudes in the + Z direction, that is, toward the gantry 10. For example, when the top plate rises to the target height, the end portion of the lower frame 63 in the Z direction protrudes to PE2, which is closer to the gantry 10 side than the position PE1 at the lower limit height. By pushing the lower frame 63 toward the gantry 10 in this way, the lower frame 63 supported by the upper frame 61 can be brought close to the gantry body 81 until just before it comes into contact with the gantry body 81. Therefore, it is possible to reduce the bending and vibration of the top plate 51 when the top plate 51 is inserted into the opening 41.

Next, the structure of the gantry 10 will be described. FIG. 6 is a side view schematically showing the inside of the gantry 10. As shown in FIG. 6, the gantry 10 has a gantry main body 81 and a gantry base portion 83. The gantry main body 81 has a rotating frame 11, a main frame 85, and a gantry arm 87. The main frame 85 is a metal frame that rotatably supports the rotating frame 11 around the central axis AR. The main frame 85 is a metal frame having an opening formed in the center. The main frame 85 is made of a metal such as aluminum. The gantry arm 87 is a metal frame made of a metal such as aluminum. The gantry arm 87 connects the main frame 85 and the gantry base portion 83. The gantry base portion 83 supports the gantry main body 81. Specifically, the gantry base portion 83 specifically has a base stand 89. The base stand 89 is a metal frame installed on the floor surface of the examination room. The base stand 89 is made of a metal such as aluminum. The base stand 89 supports the gantry main body 81 apart from the floor surface. The base stand 89 is connected to the gantry arm 87 so as to be tiltable around the tilt axis AT, and is connected to the main frame 85 via the gantry arm 87. That is, the base stand 89 supports the gantry main body 81 so as to be tiltable around the tilt axis AT. The tilt axis AT is defined as an axis horizontally orthogonal to the central axis AR.

The gantry main body 81 and the gantry base portion 83 are covered with a gantry housing (not shown in FIG. 6) 43. The gantry housing 43 has an upper housing 431 and a lower housing 432 that can be separated from each other. The upper housing 431 covers the rotating frame 11, the main frame 85, and the gantry arm 87. The lower housing 432 covers the lower part of the main frame 85. When the rotating frame 11 and the main frame 85 are tilted, the lower housing 432 is fixed to the floor surface, and the upper housing 431 is separated from the lower housing 432 and tilted.

Next, the interference between the gantry 10 and the sleeper 23 will be described. FIG. 7 is a diagram for explaining the interference between the gantry 10 and the sleeper 23, and is a diagram schematically showing a vertical cross section of the gantry main body 81, the top plate 51, and the upper frame 61 of the gantry 10. As shown in FIG. 7, the top plate 51 is inserted into the opening 41 of the gantry 10 for CT imaging. In the two-stage slide type bed 23 according to the present embodiment, in order to reduce the bending and vibration of the top plate 51, the upper frame 61 supporting the top plate 51 approaches the pedestal body 81 until just before contact. ..

The gantry body 81 may be tilted while the top plate 51 is inserted into the opening 41. However, when the lower part of the gantry body 81 (the portion below the tilt axis AT) is tilted so as to approach the upper frame 61 when the top plate 51 is inserted into the opening 41, the upper frame 61 is tilted from the gantry body 81. Specifically, it may interfere with the upper housing 431. In other words, if the upper frame 61 is present in the movement path PT of the gantry body 81 when tilting around the tilt axis AT, the gantry body 81 may interfere with the upper frame 61. If the tilt angle is limited to avoid interference, the degree of freedom in positioning the gantry main body 81 and the sleeper 23 is reduced. Further, when the approach of the upper frame 61 to the upper housing 431 is restricted in order to avoid interference, the ability of the two-stage slide type bed 23 to reduce the bending and vibration of the top plate 51 shall be fully exhibited. Can't be done.

Hereinafter, in order to solve the above problems, the operations of the gantry 10 and the berth 23 performed by the control of the gantry control circuit 33 according to the present embodiment will be described in detail.

First, the configuration of the gantry / sleeper drive system 25 and the gantry control circuit 33 according to the present embodiment will be described. FIG. 8 is a diagram showing a configuration example of the gantry / sleeper drive system 25 and the gantry control circuit 33 according to the present embodiment. As shown in FIG. 8, the gantry / sleeper drive system 25 includes a tilt drive device 251, an upper stage drive device 253, a lower stage drive device 255, and an elevating drive device 257.

The tilt drive device 251 is provided on the gantry base portion 83. The tilt drive device 251 receives a drive signal from the gantry control circuit 33 and drives the gantry main body 81 to tilt the gantry main body 81. A tilt detector 252 is connected to the drive shaft of the tilt drive device 251. The tilt detector 252 includes a rotary encoder that outputs a pulse signal each time the drive shaft of the tilt drive device 251 rotates by a predetermined angle, and an arithmetic circuit that detects the tilt angle of the gantry based on the pulse signal. The data regarding the tilt angle is supplied to the gantry control circuit 33.

The upper drive device 253 is provided on the upper frame 61. The upper drive device 253 receives a drive signal from the gantry control circuit 33 to drive the device, and slides the top plate 51. The upper detector 254 is connected to the drive shaft of the upper drive device 253. The upper detector 254 is a rotary encoder that outputs a pulse signal each time the drive shaft of the upper drive device 253 rotates by a predetermined angle, and a position with respect to the Z axis of the top plate 51 based on the pulse signal (hereinafter, referred to as a Z position). ) Is included in the calculation circuit. The data regarding the Z position of the top plate is supplied to the gantry control circuit 33.

The lower drive device 255 is provided on the lower frame 63. The lower drive device 255 receives a drive signal from the gantry control circuit 33 and drives the device, and slides the upper frame 61. The lower detector 256 is connected to the drive shaft of the lower drive device 255. The lower detector 256 includes a rotary encoder that outputs a pulse signal each time the drive shaft of the lower drive device 255 rotates by a predetermined angle, and an arithmetic circuit that detects the Z position of the upper frame 61 based on the pulse signal. The data regarding the Z position of the upper frame 61 is supplied to the gantry control circuit 33.

The elevating drive device 257 is provided on the support base 55. The elevating drive device 257 receives a drive signal from the gantry control circuit 33 and drives the elevating drive device 257 to ascend the lower frame 63 and the upper frame 61 and the top plate 51 supported by the lower frame 63. An elevating detector 258 is connected to the drive shaft of the elevating drive device 257. The elevating detector 258 is a rotary encoder that outputs a pulse signal each time the drive shaft of the elevating drive device 257 rotates by a predetermined angle, and a position (hereinafter, referred to as a Y position) of the top plate 51 with respect to the Y axis based on the pulse signal. ) Is included in the calculation circuit. The data regarding the Y position of the top plate 51 is supplied to the gantry control circuit 33.

The gantry control circuit 33 controls the gantry / sleeper drive system 25 based on the outputs from the input circuit 31, the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258. The gantry control circuit 33 according to the present embodiment holds the top plate 51 and the top plate support frame 53 so as to fix the position (absolute position) of the top plate 51 with respect to the gantry 10 before or when the gantry 10 is tilted. Move. For example, the gantry control circuit 33 according to the present embodiment performs an operation (hereinafter, referred to as an interference avoidance operation) for avoiding interference between the gantry 10 and the top plate support frame 53 before or when the gantry 10 is tilted. When the gantry 10 is tilted, the gantry control circuit 33 specifically executes the interference determination function 331, the tilt function 333, and the interference avoidance operation function 335.

In the interference determination function 331, the gantry control circuit 33 determines the distance between the gantry 10 and the top plate support frame 53 based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258. It is determined whether or not the pedestal sleeper distance (hereinafter referred to as the pedestal distance) is closer than the predetermined distance (hereinafter referred to as the interference distance). The pedestal sleeper distance is defined by the shortest distance between the gantry 10 and the top plate support frame 53. The interference determination function 331 is performed in parallel with the execution of the tilt function 333. When the tilt function 333 is executed, the gantry control circuit 33 continues to execute the tilt function 333 when the pedestal sleeper distance is longer than the interference distance. When the tilt function 333 is executed, the gantry control circuit 33 stops the tilt function 333 and executes the interference avoidance operation function 335 when the pedestal sleeper distance is shorter than the interference distance. When the interference avoidance operation function 335 is executed, the gantry control circuit 33 executes the tilt function 333 again.

In other words, the gantry control circuit 33 switches the operation mode between the normal mode and the extended mode based on the comparison between the gantry sleeper distance and the interference distance. The normal mode is a mode in which the top plate support frame 53 is brought close to the gantry main body 81 having a tilt angle of zero degrees until just before contact, and the gantry main body 81 is tilted within a range that does not interfere with the top plate support frame 53. Hereinafter, the range in which the gantry main body 81 can be tilted without interfering with the top plate support frame 53 will be referred to as a tiltable range. In the normal mode, both the top plate 51 and the top plate support frame 53 are stationary, that is, the interference avoidance operation is not performed through before and after tilting the gantry main body 81. The tilt angle range of the gantry main body 81 in the extended mode is expanded as compared with the normal mode. That is, in the extended mode, the gantry 10 is tilted after the tilt angle range is expanded by the interference avoidance operation according to the present embodiment.

9 and 10 are diagrams for explaining the interference determination function 331 of the gantry control circuit 33. As shown in FIG. 9, when the pedestal sleeper distance Dgb is longer than the interference distance Dth, the gantry 10 and the top plate support frame 53 are relatively separated, and the probability of interference is low. When the interference determination function 331 determines that the pedestal sleep distance Dgb is longer than the interference distance Dth, the mode is not switched. That is, it is set to the normal mode. As shown in FIG. 10, when the pedestal sleeper distance Dgb is shorter than the interference distance Dth, the gantry 10 and the top plate support frame 53 are close to each other, and the probability of interference is high. When it is determined by the interference determination function 331 that the pedestal sleep distance Dgb is shorter than the interference distance Dth, the normal mode is switched to the extended mode. As a result, the upper limit of the tilt angle of the gantry main body 81 can be extended while avoiding interference between the gantry main body 81 and the top plate support frame 53. The set value of the interference distance Dth can be arbitrarily set by the user via the input circuit 31 and the input circuit 109 and the like.

In the tilt function 333, the gantry control circuit 33 supplies a drive signal to the tilt drive device 251 to operate the gantry base portion 83 when a tilt instruction is given via the input circuit 31 or the like. As a result, the gantry main body 81 is tilted. At this time, since the gantry control circuit 33 does not operate the top plate 51 and the top plate support frame 53, the drive signal is not supplied to the upper drive device 253 and the lower drive device 255. In the normal mode, the gantry control circuit 33 tilts the gantry 10 within the tiltable range in the normal mode. In the extended mode, the gantry control circuit 33 tilts the gantry 10 within the tiltable range in the extended mode.

In the interference avoidance operation function 335, the gantry control circuit 33 fixes the position of the top plate 51 with respect to the gantry 10 and simultaneously holds the top plate 51 and the top plate support frame 53 so that the top plate support frame 53 is separated from the gantry 10. Move it. After the interference avoidance operation, the gantry control circuit 33 executes the tilt function 333 and tilts the gantry 10 following the interlocking movement of the top plate 51 and the top plate support frame 53. That is, in the extended mode, the gantry control circuit 33 tilts the gantry 10 in the tiltable range in the extended mode after the interference avoidance operation. Since the top plate support frame 53 is separated from the gantry main body 81 by the interference avoidance operation, the tiltable range in the extended mode is wider than the tiltable range in the normal mode. In other words, the gantry control circuit 33 can switch the tiltable range of the gantry main body 81 according to the pedestal sleeper distance. More specifically, the gantry control circuit 33 changes the tiltable range of the gantry main body 81 from the tiltable range related to the normal mode to the tiltable range related to the extended mode when the pedestal sleeper distance becomes smaller than the interference distance. Switch to.

FIG. 11 is a diagram showing the operation of the top plate 51 and the top plate support frame 53 in the extended mode, and is a diagram showing the gantry main body 81 and the sleeper 23 before and after the interference avoidance operation. As shown in the upper part of FIG. 11, before the interference avoidance operation, the lower part of the gantry main body 81 is tilted in the direction approaching the upper frame 61, and the pedestal sleeper distance is shorter than the interference distance. At this point, it is assumed that the tip of the top plate 51 in the Z direction is located at Ztop_bf and the tip of the upper frame 61 in the Z direction is located at Zfra_bf. If the pedestal distance is shorter than the interference distance, the operating mode is switched to extended mode. The gantry control circuit 33 is driven in the upper stage so that the top plate 51 with respect to the upper frame 61 and the upper frame 61 with respect to the lower frame 63 move in opposite directions when a tilt instruction is given via the input circuit 31 or the like in the extended mode. The device 253 and the lower drive device 255 are driven substantially at the same time. Specifically, the gantry control circuit 33 interlocksly controls the upper drive device 253 and the lower drive device 255 according to a predetermined moving speed time change curve (hereinafter, referred to as a speed curve). The speed curve shows the transition of the speed of the driven object with the elapsed time from the start of driving. Specifically, the speed curve of the upper drive device 253 shows the temporal transition of the moving speed of the top plate 51 with respect to the upper frame 61, and the speed curve of the lower drive device 255 shows the upper frame with respect to the lower frame 63. The temporal transition of the relative movement speed of 61 is shown. It is preferable that the speed curve of the upper drive device 253 and the speed curve of the lower drive device 255 are set in opposite directions and at the same speed at each time point.

By interlocking control according to the speed curve, the top plate support frame 53 is slid in the −Z direction and the top plate 51 is slid in the opposite + Z direction, and the absolute position of the top plate 51 (position in XYZ space, that is, apparent appearance). The top plate support frame 53 can be retracted without moving the position). As shown in the lower part of FIG. 11, after the interference avoidance operation, the position Ztop_af of the tip of the top plate 51 in the Z direction is the same as the position Ztop_bf before the movement, and the position Zfra_af of the tip of the upper frame 61 in the Z direction is , It will be located behind (-Z direction) the position Zfra_bf before the movement. Since the upper frame 61 has a predetermined thickness in the Z direction, even if the absolute position of the top plate 51 does not change, the tiltable range of the gantry main body 81 is expanded by retracting the upper frame 61. By the interference avoidance operation according to the present embodiment, only the upper frame 61 can be retracted while fixing the absolute position of the top plate 51, so that the upper frame is compared with the case where both the top plate 51 and the upper frame 61 are retracted. It is possible to prevent the top plate 51 from being repositioned after the 61 is retracted.

Next, the tilt operation control by the gantry control circuit 33 according to the present embodiment will be described separately for the first embodiment and the second embodiment.

FIG. 12 is a diagram showing a typical flow of tilt operation control performed under the control of the gantry control circuit 33 according to the first embodiment. FIG. 13 is a diagram schematically showing the operation of the sleeper 23 and the gantry main body 81 according to the first embodiment. It is assumed that the top plate 51 is inserted into the opening 41 of the gantry main body 81 at the start of the tilt operation control in FIG.

As shown in FIG. 12, the gantry control circuit 33 waits for the tilt button provided on the input circuit 31 to be pressed (step SA1). For example, in order to avoid irradiation of the eyes (more specifically, the crystalline lens) of the subject O placed on the top plate with X-rays, an anatomical reference line such as an OM (orbito-meatal baseline) line is used. The gantry body 81 is tilted by a desired angle so that the scanning surface is tilted. When a user such as a radiologist determines that tilting is necessary, he / she presses the tilt button.

When step SA1 is performed (step SA1: YES), the gantry control circuit 33 executes the tilt function 333 (step SA2). In step SA2, the gantry control circuit 33 repeatedly supplies a drive signal to the tilt drive device 251 while the tilt button is pressed, and tilts the gantry main body 81 at a predetermined angular velocity. It is assumed that the tilt direction of the gantry main body 81 in this embodiment is the direction in which the lower portion of the gantry main body 81 approaches the upper frame 61. When the tilt button is released, the gantry control circuit 33 stops the supply of the drive signal to the tilt drive device 251 and stops the tilt operation of the gantry main body 81. That is, the tilt button is assumed to be a deadman switch for safety.

While the gantry body 81 is tilting, the gantry control circuit 33 executes the interference determination function 351 (step SA3). In step SA3, the gantry control circuit 33 determines whether or not the gantry main body 81 is close to the top plate support frame 53 to a predetermined distance (interference distance). In other words, the gantry control circuit 33 confirms whether or not a sufficient space (clearance) is secured between the gantry main body 81 and the top plate support frame 53. Specifically, in step SA3, the gantry control circuit 33 calculates the pedestal berth distance based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258, and the pedestal berth distance is determined. It is repeatedly determined whether or not the distance is closer than the predetermined interference distance. In this determination, it is not always necessary to calculate the pedestal sleeper distance based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258. A table in which the output from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258 is associated with the pedestal distance is created in advance, and the tilt detector 252, the upper detector 254, and the lower detector 256 are created. And the table may be applied to the output from the elevating detector 258 to determine the pedestal distance. Alternatively, a table is created in advance in which the output from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258 is associated with the determination result of whether or not the pedestal distance is closer than the interference distance. May be done. In this case, the gantry control circuit 33 applies the table to the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258 to perform the above determination.

When it is determined that the pedestal sleeper distance is longer than the interference distance, that is, the gantry main body 81 is not closer to the upper frame 61 than the interference distance (step SA3: NO), the gantry control circuit 33 is the tilt drive device 251. The drive signal is repeatedly supplied to the frame, and the gantry main body 81 is continuously tilted at a predetermined angular velocity.

On the other hand, when the pedestal sleeper distance reaches the interference distance, that is, when it is determined that the gantry main body 81 is closer to the upper frame 61 than the interference distance (step SA3: YES), the gantry control circuit 33 is a tilt drive device. The 251 is interlocked and the tilt operation of the gantry main body 81 is stopped (interlock stopped) (step SA4). The interlock stop is also activated when the tilt button is pressed. When the interlock stop is performed, the gantry control circuit 33 causes the display circuit 29 to display a warning. Examples of the warning display mode include blinking and warning messages. Further, the gantry control circuit 33 may, for example, blink an LED lamp or the like embedded in the tilt button, or may emit a warning sound via a speaker provided in the gantry main body 81 or the like.

After the interlock is stopped, the gantry control circuit 33 waits for the tilt button to be pressed again. For example, when the user determines that the X-ray CT scan is performed at the tilt angle of the current gantry main body 81, the scan button is pressed. In this case, the gantry control circuit 33 determines that the tilt button is not pressed again (step SA5: NO), and the tilt operation control according to the present embodiment ends.

On the other hand, when the user gives priority to further tilt, the tilt button is pressed again. When the tilt button is pressed again (step SA5: YES), the gantry control circuit 33 executes the mode switching function 353 (step SA6). In step SA6, the gantry control circuit 33 executes the interference avoidance operation function 335 (step SA6). In step SA6, the gantry control circuit 33 performs an interference avoidance operation. That is, the gantry control circuit 33 slides the top plate 51 and the upper frame 61 in opposite directions, and slides the upper frame 61 to the retracted position Ps while fixing the absolute position of the top plate 51. The retracted position Ps is set to an arbitrary position on the pedestal closest approach position Pc side rather than a position where the gantry main body 81 does not interfere with the upper frame 61 even when the gantry main body 81 is closest to the top plate 51. The distance from the gantry closest position Pc to the retracted position Ps can be set to an arbitrary value via the input circuit 31 or the like. In the first embodiment, the upper frame 61 is slid at once from the pedestal closest position Pc to the retracted position Ps.

When step SA6 is performed, the gantry control circuit 33 executes the tilt function 333 (step SA7). In step SA7, the gantry control circuit 33 controls the tilt drive device 251 to tilt the gantry main body 81 to a tilt angle desired by the user. Specifically, the user presses the tilt button until the gantry main body 81 is located at a desired tilt angle, and releases the tilt button when the gantry main body 81 is located at a desired tilt angle. While the tilt button is pressed, the gantry control circuit 33 repeatedly supplies a drive signal to the tilt drive device 251 to tilt the gantry main body 81 at a predetermined angular velocity. When the tilt button is released, the gantry control circuit 33 supplies a stop signal to the tilt drive device 251 to stop the tilt operation of the gantry main body 81.

In step SA7, the gantry control circuit 33 may execute the interference determination function 351. In this case, the gantry control circuit 33 calculates the pedestal berth distance based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258, and the pedestal berth distance is greater than the predetermined interference distance. Is repeatedly determined whether or not they are approaching. When it is determined that the pedestal berth distance is longer than the interference distance, the gantry control circuit 33 supplies a drive signal to the tilt drive device 251 to tilt the gantry main body 81, and the gantry sleeper distance is shorter than the interference distance. If it is determined, the tilt drive device 251 is interlocked and controlled to stop the tilt operation of the gantry main body 81.

When the tilt operation of the gantry main body 81 is stopped, the X-ray CT scan is performed under the control of the gantry control circuit 33.

This completes the description of the tilt operation control according to the first embodiment.

Next, the tilt operation control according to the second embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 is a diagram showing a typical flow of tilt operation control performed under the control of the gantry control circuit 33 according to the second embodiment. FIG. 15 is a diagram schematically showing the operation of the sleeper 23 and the gantry main body 81 according to the second embodiment. Since steps SB1 to SB5 in FIGS. 14 and 15 are the same steps as steps SA1 to SA5 in FIGS. 12 and 13, respectively, the description thereof will be omitted.

When the tilt button is pressed in step SB5, the gantry control circuit 33 executes the interference avoidance operation function 335 according to the second embodiment (step SB6). In step SB6, the gantry control circuit 33 slides the top plate 51 and the upper frame 61 in opposite directions, and retracts the upper frame 61 toward the retracted position Ps by a predetermined distance Dm while fixing the absolute position of the top plate 51. .. The predetermined distance Dm is preferably a distance shorter than 1/2 of the distance from the gantry closest position Pc to the retracted position Ps. Specifically, the predetermined distance Dm is preset to a relatively short distance such as 1 cm or 5 cm. The upper frame is located at the position Ps'between the pedestal closest approach position Pc and the retracted position Ps by sliding the predetermined distance Dm.

When step SB6 is performed, the gantry control circuit 33 executes the tilt function 333 (step SB7). In step SB7, the gantry control circuit 33 supplies a drive signal to the tilt drive device 251 and tilts the gantry main body 81 by a predetermined angle. Specifically, the predetermined angle is set to the tilt angle corresponding to the predetermined distance Dm in step SB6. That is, the predetermined angle is set to the angle from the current angle until the pedestal sleeper distance reaches the predetermined interference distance. When the gantry main body 81 is tilted by a predetermined angle, the gantry control circuit 33 interlocks the tilt drive device 251 to stop the tilt operation of the gantry main body 81. The gantry control circuit 33 may execute the interference determination function 351 in order to bring the gantry sleeper distance closer to a predetermined interference distance.

After the interlock is stopped, the gantry control circuit 33 determines whether or not to end the tilt (step SB8). In step SB8, the gantry control circuit 33 determines whether or not the upper frame 61 has been retracted to the retracted position Ps based on the outputs from, for example, the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258. judge. If the evacuation position Ps has not been retracted, the gantry control circuit 33 determines that the tilt is not completed (step SB8: NO). In this case, the gantry control circuit 33 again retracts the upper frame 61 by a predetermined distance Dm (step SB6) and tilts the gantry main body 81 by a predetermined angle (step SB7). The predetermined distance Dm may be the same value or different values in each interference avoidance operation.

Then, when the user determines that the gantry main body 81 is positioned at a desired tilt angle, the user releases the tilt button. When the user releases the tilt button, the gantry control circuit 33 determines that the tilt is finished (step SB8: YES).

When the tilt operation of the gantry main body 81 is stopped, the X-ray CT scan is performed under the control of the gantry control circuit 33.

The gantry control circuit 33 may determine that the tilt is completed even when it is determined that the upper frame 61 has been retracted to the retracted position Ps. As a result, it is possible to avoid interference between the gantry main body 81 and the upper frame 61. Further, in the above description, it is assumed that the interlock is stopped every time the gantry main body 81 approaches the upper frame 61 in the extended mode. However, this embodiment is not limited to this. When the gantry control circuit 33 determines that the gantry main body 81 has approached the upper frame 61, the gantry control circuit 33 may perform an interference avoidance operation between the top plate 51 and the upper frame 61. As a result, the gantry main body 81 can be positioned without pressing the tilt button many times.

Further, in step SB6 and step SB7, the interference avoidance operation and the tilt are alternately performed. However, this embodiment is not limited to this. That is, the gantry control circuit 33 may simultaneously control the tilt drive device 251 and the upper drive device 253 and the lower drive device 255 to simultaneously perform the interference avoidance operation and the tilt of the gantry main body 81. By performing the interference avoidance operation and the tilt at the same time, the positioning of the gantry main body 81 can be performed in a shorter time than in the case where the interference avoidance operation and the tilt are alternately performed.

This completes the description of the tilt operation control according to the second embodiment.

As described above, in the first embodiment, the upper frame 61 is slid all at once to the non-interfering position, and in the second embodiment, the upper frame 61 is intermittently slid to the retracted position Ps. The interference avoidance operation of the first embodiment and the interference avoidance operation of the second embodiment can be arbitrarily selected by the user via the input circuit 31 or the input circuit 109 or the like. The interference avoidance operation of the first embodiment is easy to control because the upper frame 61 retracts to the retracted position Ps at once. In the interference avoidance operation of the second embodiment, since it is not necessary to retract the upper frame 61 to the retracted position Ps at once, the time efficiency related to positioning is improved, and the throughput of CT inspection is improved. Further, in the interference avoidance operation of the second embodiment, the gantry main body 81 follows the intermittent evacuation of the upper frame 61 and tilts. Therefore, in order to bring the upper frame 61 closer to just before the gantry main body 81, the upper frame 61 It is not necessary to bring the upper frame 61 closer to the gantry main body 81 again after the evacuation.

In the above embodiment, the gantry control circuit 33 calculates the gantry sleeper distance based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258. However, this embodiment is not limited to this. For example, the gantry control circuit 33 calculates the pedestal sleeper distance based on the position detection signal from the position detector attached to the surface of the berth 23 and the position detection signal from the position detector attached to the surface of the gantry 10. You may. As the position detector, a detector based on any existing principle such as an electric principle, a magnetic principle, and an optical principle can be used.

In the above embodiment, the interference avoidance operation has been described by taking as an example the interference between the gantry main body 81 and the top plate support frame 53 at the time of tilting. However, this embodiment is not limited to this. Hereinafter, other interference avoidance operations will be briefly described.

(Modification example 1)
The gantry control circuit 33 according to the first modification performs an interference avoidance operation related to the sleeper 23 in order to avoid interference between the gantry main body 81 and the top plate support frame 53 at the time of slewing of the gantry main body 81. Hereinafter, the first modification will be described. In the following description, components having substantially the same functions as those of the present embodiment are designated by the same reference numerals and will be described in duplicate only when necessary.

In the gantry / sleeper drive system 25 according to the first modification, the gantry main body 81 is swiveled around a swivel axis. The swivel axis is a vertical axis parallel to the Y axis, and is set so as to penetrate a substantially central portion of the gantry body 81 with respect to the X axis. The gantry / sleeper drive system 25 has a drive device for a slew (hereinafter, referred to as a slew drive device) (hereinafter, referred to as a slew drive device), which is not shown. The gantry control circuit 33 controls the slew drive device of the gantry / sleeper drive system 25, and slews the gantry main body 81 around the turning axis.

Even when the gantry main body 81 is slung while the top plate 51 is arranged in the opening 41 of the gantry main body 81, the upper frame 61 and the gantry main body 81, more specifically, the upper housing 431 may interfere with each other. In order to avoid this interference, the gantry control circuit 33 executes the interference determination function 331, the tilt function 333, and the interference avoidance operation function 335 even at the time of slew, as in the case of tilting. The tilt function 333 according to the first modification is replaced with the slew function. In the slew function, the gantry control circuit 33 supplies a drive signal to the slew drive device to slew the gantry main body 81. Specifically, the gantry control circuit 33 executes the interference determination function 331 at the time of slewing the gantry main body 81, and determines whether or not the gantry sleeper distance between the gantry main body 81 and the upper frame 61 is within the interference distance. judge. When it is determined that the pedestal sleeper distance is not within the interference distance, the gantry control circuit 33 maintains the slew function. In this case, the gantry control circuit 33 controls the slew drive device according to an instruction from the user via the input circuit 31 or the like, and slews the gantry main body 81 around the turning axis. On the other hand, when it is determined that the pedestal sleeper distance is within the interference distance, the gantry control circuit 33 executes the interference avoidance operation function 335. In the interference avoidance operation function 335, the gantry control circuit 33 slides the top plate 51 and the upper frame 61 so that the upper frame 61 is separated from the gantry main body 81 while fixing the position of the top plate 51 with respect to the gantry main body 81. After retracting the upper frame 61, the gantry control circuit 33 slides the gantry body 81 in the tilt angle range related to the extended mode.

As described above, the X-ray computed tomography apparatus according to the first modification can retract the upper frame 61 without changing the absolute position of the top plate 51 even when the gantry main body 81 is slewed.

(Modification 2)
The gantry control circuit 33 according to the second modification performs an interference avoidance operation related to the sleeper 23 in order to avoid interference between the gantry main body 81 and the top plate support frame 53 when the top plate moves in the minor axis direction. Hereinafter, the second modification will be described. In the following description, components having substantially the same functions as those of the present embodiment are designated by the same reference numerals and will be described in duplicate only when necessary.

The lower frame 63 of the sleeper 23 according to the second modification further slidably supports the top plate 51 and the upper frame 61 in a direction parallel to the short axis of the top plate 51, that is, in the X direction. The gantry / sleeper drive system 25 slides the top plate 51 in the X direction. The gantry / sleeper drive system 25 has a drive device (hereinafter, referred to as a short axis slide drive device) for sliding in the X direction (hereinafter referred to as a short axis slide drive device), which is not shown. The gantry control circuit 33 controls the short-axis slide drive device of the gantry / sleeper drive system 25, and slides the top plate 51 and the upper frame 61 integrally in the X direction.

Even when the top plate 51 and the upper frame 61 slide in the X direction in a state where the top plate 51 is arranged in the opening 41 of the gantry main body 81, the upper frame 61 and the gantry main body 81, more specifically, the upper casing Can interfere with body 431. In order to avoid this interference, the gantry control circuit 33 executes the interference determination function 331, the tilt function 333, and the interference avoidance operation function 335 even when the top plate 51 and the upper frame 61 in the X direction slide, as in the case of tilting. To do. The tilt function 333 according to the second modification is replaced with the short axis slide function. In the short-axis slide function, the gantry control circuit 33 supplies a drive signal to the short-axis slide drive device, and slides the top plate 51 and the upper frame 61 integrally in the X direction. Specifically, the gantry control circuit 33 executes the interference determination function 331 when the top plate 51 and the upper frame 61 in the X direction slide, and the pedestal sleeper distance between the gantry main body 81 and the upper frame 61 interferes. Determine if it is within the distance. When it is determined that the pedestal sleeper distance is not within the interference distance, the gantry control circuit 33 maintains the short axis slide function 333. In this case, the gantry control circuit 33 controls the short-axis slide drive device according to an instruction from the user via the input circuit 31 or the like, and slides the top plate 51 and the upper frame 61 in the X direction. On the other hand, when it is determined that the pedestal sleeper distance is within the interference distance, the gantry control circuit 33 executes the interference avoidance operation function 335. In the interference avoidance operation function 335, the gantry control circuit 33 slides the top plate 51 and the upper frame 61 so that the upper frame 61 is separated from the gantry main body 81 while fixing the position of the top plate 51 with respect to the gantry main body 81. After retracting the upper frame 61, the gantry control circuit 33 can further slide the top plate 51 and the upper frame 61 toward the upper housing 431 in the X direction.

As described above, the X-ray computed tomography apparatus according to the second modification retracts the upper frame 61 without changing the absolute position of the top plate 51 even when the top plate 51 and the upper frame 61 slide in the X direction. Can be made to.

(Modification 3)
The gantry control circuit 33 according to the third modification performs an interference avoidance operation related to the sleeper 23 in order to avoid interference between the gantry main body 81 and the top plate support frame 53 when the top plate 51 is lowered. Hereinafter, the third modification will be described. In the following description, components having substantially the same functions as those of the present embodiment are designated by the same reference numerals and will be described in duplicate only when necessary.

Even when the top plate 51 and the upper frame 61 descend in the Y direction in a state where the top plate 51 is arranged in the opening 41 of the gantry main body 81, the upper frame 61 and the gantry main body 81, more specifically, the upper casing Can interfere with body 431. In order to avoid this interference, the gantry control circuit 33 executes the interference determination function 331, the tilt function 333, and the interference avoidance operation function 335 even when the top plate 51 and the upper frame 61 are lowered, as in the case of tilting. The tilt function 333 according to the third modification is replaced with the top plate elevating function. In the top plate elevating function, the gantry control circuit 33 supplies a drive signal to the elevating drive device 257 and raises or lowers the top plate 51 and the upper frame 61. Specifically, the gantry control circuit 33 executes the interference determination function 331 when the top plate 51 and the upper frame 61 in the X direction descend, and the pedestal sleeper distance between the gantry main body 81 and the upper frame 61 interferes. Determine if it is within the distance. When it is determined that the pedestal sleeper distance is not within the interference distance, the gantry control circuit 33 maintains the top plate elevating function 333. In this case, the gantry control circuit 33 controls the elevating drive device 257 according to an instruction from the user via the input circuit 31 and the like, and lowers the top plate 51 and the upper frame 61 in the Y direction. On the other hand, when it is determined that the pedestal sleeper distance is within the interference distance, the gantry control circuit 33 switches to the interference avoidance operation function 335. In the interference avoidance operation function 335, the gantry control circuit 33 slides the top plate 51 and the upper frame 61 so that the upper frame 61 is separated from the gantry main body 81 while fixing the position of the top plate 51 with respect to the gantry main body 81. After retracting the upper frame 61, the gantry control circuit 33 can further lower the top plate 51 and the upper frame 61 in the Y direction.

As described above, the X-ray computed tomography apparatus according to the third modification retracts the upper frame 61 without changing the absolute position of the top plate 51 even when the top plate 51 and the upper frame 61 descend in the Y direction. Can be made to.

(Modification example 4)
In the above embodiment, the gantry control circuit 33 moves the top plate 51 with respect to the three axes of the Z axis, the X axis, and the Y axis. However, this embodiment is not limited to this. For example, the sleeper 23 may be equipped with a mechanism capable of rotating the top plate 51 around an arbitrary rotation axis set in the XYZ space. In this case, the gantry control circuit 33 can rotate the top plate 51 around the rotation axis. With the above configuration, for example, the top plate 51 can be inserted diagonally with respect to the gantry opening 41, and the degree of freedom in positioning the top plate 51 can be further improved. In this case as well, the gantry control circuit 33 can perform an interference avoidance operation in order to avoid interference between the gantry main body 81 and the top plate support frame 53, as in the above embodiment.

(Modification 5)
In the above embodiment, the top plate support frame 53 such as the upper frame 61 is retracted in the interference avoidance operation. However, this embodiment is not limited to this. For example, when the support base 55 has a mechanism that can move in the Z direction, the support base 55 may be retracted. For example, a rail along the Z axis may be provided on the floor surface of the CT examination room, and a pulley for traveling the rail may be provided on the bottom of the support base 55 or the like. The support base 55 is provided with a pulley drive device for driving the pulley as a pedestal / sleeper drive system 25. The gantry control circuit 33 controls the pulley drive device and can move the support pedestal 55 in the Z direction.

In the interference avoidance operation, the gantry control circuit 33 moves the top plate 51 and the pedestal 55 in an interlocking manner so that the pedestal 55 is separated from the pedestal 10 while fixing the position of the top plate 51 with respect to the gantry 10. At this time, it is not necessary to drive the lower drive device 255 for sliding the upper frame 61. The gantry control circuit 33 is a predetermined speed for moving the upper drive device 253 and the pulley drive device in the opposite directions and at the same speed at each time point in the same manner as in the above embodiment. Control in conjunction with the curve. After the interference avoidance operation, the gantry control circuit 33 tilts the gantry 10 following the interlocking movement of the top plate 51 and the support base 55.

As described above, according to the modified example 5, even if the bed is not a two-stage slide type bed, the interference avoidance operation can be performed if the bed is equipped with the moving mechanism of the support base 55.

(Modification 6)
In the above embodiment, the upper drive device 253, the lower drive device 255, and the elevating drive device 257 are controlled by the gantry control circuit 33, and the gantry control circuit 33 is provided on the gantry 10. However, this embodiment is not limited to this. The upper drive device 253, the lower drive device 255, and the elevating drive device 257 may be controlled not by the gantry control circuit 33 provided on the gantry 10 but by another control circuit provided on the berth 23. This makes it possible to perform the interference avoidance operation only with the configuration of the sleeper 23.

(Modification 7)
In the above embodiment, the sleeper 23 has a structure that mechanically moves in the Z direction as the lower frame 63 moves up and down. However, the present embodiment is not limited to this, and the sleeper 23 has a structure in which the lower frame 63 does not mechanically move in the Z direction as the lower frame 63 moves up and down, that is, a structure in which the lower frame 63 moves up and down in the vertical direction. You may.

(Modification 8)
In the above embodiment, when the distance between the gantry 10 and the top plate support frame 53 (the pedestal sleeper distance) is within a predetermined distance, the gantry control circuit 33 supports the top plate while fixing the position of the top plate 51 with respect to the gantry 10. The top plate 51 and the top plate support frame 53 are moved so that the frame 53 is separated from the gantry 10. However, this embodiment is not limited to this. The gantry control circuit 33 according to the modified example 8 supports the top plate while fixing the position of the top plate 51 with respect to the gantry 10 when the distance between the gantry 10 and the top plate support frame 53 (the pedestal sleeper distance) is outside the predetermined distance. The top plate 51 and the top plate support frame 53 are moved so that the frame 53 approaches the gantry 10. Hereinafter, the X-ray computed tomography apparatus according to the modified example 8 will be described. In the following description, components having substantially the same functions as those in the above-described embodiment will be designated by the same reference numerals and will be described in duplicate only when necessary.

FIG. 16 is a diagram schematically showing the operation of the sleeper 23 and the gantry main body 81 according to the modified example 8. It is assumed that the gantry main body 81 is tilted at a predetermined angle at the start of the tilt operation control of FIG. 16, and the top plate 51 is inserted into the opening 41 of the gantry main body 81.

As shown in FIG. 16, the gantry control circuit 33 waits for pressing the −tilt button for tilting the lower portion of the gantry main body 81 in a direction away from the upper frame 61 (hereinafter, minus direction). For example, a user such as a radiologist presses the-tilt button to position the patient or the like.

-While the tilt button is pressed, the gantry control circuit 33 repeatedly supplies a drive signal to the tilt drive device 251 to tilt the gantry main body 81 in the negative direction at a predetermined angular velocity. The user releases the-tilt button when the gantry body 81 reaches a predetermined tilt angle. -When the tilt button is released, the gantry control circuit 33 stops the supply of the drive signal to the tilt drive device 251 and stops the tilt operation of the gantry main body 81.

When the tilt operation of the gantry main body 81 is stopped, the gantry control circuit 33 determines whether or not the gantry main body 81 is separated from the top plate support frame 53 by a predetermined distance (hereinafter referred to as a following distance). Specifically, the gantry control circuit 33 calculates the pedestal sleeper distance based on the outputs from the tilt detector 252, the upper detector 254, the lower detector 256, and the elevating detector 258, and the pedestal sleeper distance is calculated from the tracking distance. It is repeatedly determined whether or not they are separated from each other.

When it is determined that the pedestal sleeper distance is shorter than the following distance, that is, the pedestal main body 81 is not separated from the upper frame 61 by the following distance, the pedestal control circuit 33 stops the operation.

On the other hand, when it is determined that the pedestal sleeper distance is longer than the following distance, that is, the pedestal main body 81 is separated from the upper frame 61 by the following distance, the pedestal control circuit 33 executes the following operation function. In the follow-up operation function, the gantry control circuit 33 synchronously controls the upper drive device 253 and the lower drive device 255, slides the top plate 51 and the upper frame 61 in the same speed and in opposite directions, and makes the top plate 51 absolute. The upper frame 61 is brought closer to the gantry main body 81 while the position is fixed. During the approach, the pedestal control circuit 33 calculates the pedestal sleeper distance, repeatedly determines whether or not the pedestal sleeper distance is closer than the interference distance, and if the pedestal sleeper distance is shorter than the interference distance, the upper drive device 253. And the lower drive device 255 are interlocked to stop the top plate 51 and the upper frame 61. With the follow-up operation function, the upper frame 61 can be brought closer to the gantry main body 81 by following the tilt operation of the gantry main body 81 while fixing the absolute position of the top plate 51. Since the upper frame 61 can be brought as close as possible to the gantry main body 81, the bending of the top plate 51 in the opening 41 can be reduced.

In the above operation example, the top plate 51 and the upper frame 61 perform the follow-up operation after the gantry main body 81 finishes reaching the desired tilt angle. However, the gantry control circuit 33 may intermittently alternately perform the tilt operation of the gantry main body 81 and the following operation of the top plate 51 and the upper frame 61 until the gantry main body 81 reaches a desired tilt angle. .. Further, the gantry control circuit 33 may simultaneously tilt the gantry main body 81 and follow the top plate 51 and the upper frame 61. As a result, the positioning of the gantry main body 81 can be performed in a short time as compared with the case where the interference avoidance operation and the tilt are alternately performed.

(Summary)
As described above, the X-ray computed tomography apparatus according to the present embodiment includes a gantry 10, a sleeper 23, and a gantry control circuit 33. The gantry 10 has an X-ray tube 13 and an X-ray detector 15. The sleeper 23 has a top plate 51 on which the subject O is placed, and a top plate support frame 53 that movably supports the top plate 51 along the long axis. The gantry control circuit 33 moves the top plate 51 and the top plate support frame 53 so as to fix the position of the top plate 51 with respect to the gantry 10.

With the above configuration, the top plate support frame 53 can be retracted or brought closer to the gantry main body 81 while fixing the absolute position of the top plate 51. Therefore, the X-ray computed tomography apparatus according to the present embodiment adjusts the clearance between the top plate support frame 53 and the gantry main body 81 without burdening the patient, as compared with the case where the absolute position of the top plate 51 changes. Can be done. Further, since the absolute position of the top plate 51 does not change before and after the interference avoidance operation or the gantry following operation, it is not necessary to position the top plate 51 again after the interference avoidance operation or the like. Therefore, the positioning efficiency is improved as compared with the conventional case where the tilt angle and the position of the top plate support frame 53 are limited.

More specifically, the X-ray computed tomography apparatus according to the present embodiment is a gantry when the top plate support frame 53 is brought as close as possible to the gantry 10 in order to reduce bending and vibration of the top plate 51. When tilting the main body 81 or the like, the top plate support frame 53 can be retracted from the gantry 10 while fixing the absolute position of the top plate 51. Therefore, according to the present embodiment, interference can be avoided only by driving the sleeper 23 without setting restrictions on the tilt angle, the position of the top plate support frame 53, and the like. Therefore, the ability of the X-ray computed tomography apparatus provided with the two-stage slide type bed 23 can be maximized.

Thus, according to the present embodiment, it is possible to increase the degree of freedom in positioning the pedestal and the bed while reducing the bending and vibration of the top plate.

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 included in the scope of the invention described in the claims and the equivalent scope thereof.

10 ... gantry, 11 ... rotating frame, 13 ... X-ray tube, 15 ... X-ray detector, 17 ... high voltage generator, 21 ... rotary drive, 23 ... sleeper, 25 ... gantry / sleeper drive system, 27 ... data Collection circuit, 29 ... Display circuit, 31 ... Input circuit, 33 ... Stand control circuit, 41 ... Opening, 43 ... Stand housing, 51 ... Top plate, 53 ... Top plate support frame, 55 ... Support base, 61 ... Upper frame , 63 ... lower frame, 65 ... X-link, 67 ... base, 75 ... fulcrum, 76 ... lead screw, 77 ... braking device, 78 ... nut, 81 ... gantry body, 83 ... gantry base, 85 ... main frame , 87 ... gantry arm, 89 ... base stand, 100 ... console, 101 ... preprocessing circuit, 103 ... reconstruction circuit, 105 ... image processing circuit, 107 ... display circuit, 109 ... input circuit, 111 ... main memory circuit, 113 ... system control circuit, 251 ... tilt drive device, 252 ... tilt detector, 253 ... upper drive device, 254 ... upper detector, 255 ... lower drive device, 256 ... lower detector, 257 ... lift drive device, 258 ... lift Detector, 331 ... Interference judgment function, 333 ... Tilt function, 335 ... Interference avoidance operation function.

Claims (12)

A pedestal equipped with an X-ray tube and an X-ray detector,
A top plate on which a subject is placed, a first support portion that movably supports the top plate along the long axis, and a second support portion that movably supports the first support portion along the long axis. A sleeper with a support and
A first sleeper drive unit for moving the top plate along the long axis, and
A second sleeper drive unit for moving the first support unit along the long axis, and
A gantry drive unit for moving the gantry and
An operation unit for instructing the movement of the gantry in a predetermined direction, and
A control unit for moving the top plate and the first support portion is provided so as to fix the position of the top plate with respect to the gantry.
When the distance between the gantry and the first support portion is outside the predetermined distance, the control unit secures the position of the top plate with respect to the gantry so that the first support portion approaches the gantry. By moving the top plate and the first support portion ,
When the distance between the gantry and the first support portion is within a predetermined distance, the control unit interlocks the first berth drive unit and the second berth drive unit to position the top plate with respect to the gantry. away from the first support portion is the frame while fixing a, and is moved in front Symbol the first support portion relative to the second support portion in a first direction away from said frame along said major axis The top plate is moved with respect to the first support portion in a second direction approaching the gantry.
The control unit controls the gantry drive unit when instructed via the operation unit to move the gantry in the predetermined direction, and the distance that changes with the operation of the gantry is determined. When the distance is reached, the gantry drive unit, the first sleeper drive unit, and the second sleeper drive unit are interlocked with each other, and the first support unit is moved by a predetermined short distance toward a position that does not interfere with the gantry. The gantry is further intermittently moved in the predetermined direction while being intermittently moved, and in the intermittent movement of the first support portion, the first support portion is moved with respect to the second support portion on the long axis. The top plate is moved in the first direction and the top plate is moved in the second direction with respect to the first support portion.
X-ray computed tomography equipment. Wherein, when the distance is not within said predetermined distance, controls the gantry driving unit for moving the gantry, X-rays computed tomography apparatus according to claim 1. An operation unit for instructing the movement of the gantry in a predetermined direction is further provided.
The control unit moves the gantry in the predetermined direction when instructed via the operation unit, and when the distance reaches the predetermined distance, the first position does not interfere with the gantry. After moving the support portion, the gantry is further moved in the predetermined direction.
The X-ray computed tomography apparatus according to claim 1 . The gantry has a gantry body that houses the X-ray tube and the X-ray detector, and a base that supports the gantry body so as to be tiltable around a tilt axis that is horizontally orthogonal to the rotation axis.
The gantry drive unit tilts the gantry body around the tilt axis.
The X-ray computed tomography apparatus according to claim 1 . The gantry drive unit tilts the gantry body around the tilt axis so that the lower part of the gantry body approaches the first support portion.
When the distance between the lower portion of the gantry main body and the first support portion is within the predetermined distance, the control unit fixes the position of the top plate with respect to the gantry and causes the first support portion from the gantry. The first sleeper drive unit and the second sleeper drive unit are interlocked and controlled so as to be separated from each other.
The X-ray computed tomography apparatus according to claim 4 . The gantry driving unit pivots the frame around a vertical axis, X-rays computed tomography apparatus according to claim 1. The second support portion further supports the top plate and the first support portion so as to be movable in a direction parallel to the minor axis of the top plate.
When the distance that changes with the movement of the first support portion by the second support portion is within the predetermined distance, the control unit sets the first support portion with respect to the second support portion. And the top plate is moved in the second direction with respect to the first support portion.
The X-ray computed tomography apparatus according to claim 1 . The sleeper further has a third support portion that movably supports the top plate and the first support portion in the vertical direction.
When the distance that changes with the movement of the first support portion by the third support portion is within the predetermined distance, the control unit sets the first support portion with respect to the second support portion. And the top plate is moved in the second direction with respect to the first support portion.
The X-ray computed tomography apparatus according to claim 1 . The X-ray computed tomography apparatus according to claim 1, wherein the control unit switches the movable range of the gantry according to a distance between the gantry and the first support portion. The control unit has a first mode capable of tilting in a first tilt angle range and a second tilt angle wider than the first tilt angle range, depending on the distance between the gantry and the first support unit. The X-ray computed tomography apparatus according to claim 9 , which switches between a second mode that can be tilted in a range. The X-ray computed tomography apparatus according to claim 1, wherein the control unit simultaneously moves the top plate and the first support unit. The top plate on which the subject is placed and
A first support portion that movably supports the top plate along the long axis,
A second support portion that movably supports the first support portion along the long axis, and a second support portion.
An operation unit for instructing the movement of the gantry in a predetermined direction, and
It is provided with a moving portion for moving the top plate and the first support portion so as to fix the position of the top plate with respect to a frame having an imaging mechanism.
When the distance between the gantry and the first support portion is outside the predetermined distance, the moving portion is such that the first support portion approaches the gantry while fixing the position of the top plate with respect to the gantry. By moving the top plate and the first support portion ,
The mobile unit, when the distance between the frame and the first support portion is within a predetermined distance, such that the first supporting portion while fixing the position of the top plate relative to the frame away from said pedestal, before Symbol A second support that moves the first support along the long axis in a first direction away from the gantry and approaches the top plate to the gantry with respect to the first support. Move in the direction of
The moving unit moves the gantry in the predetermined direction when instructed via the operation unit, and when the distance that changes with the operation of the gantry reaches the predetermined distance, the gantry While intermittently moving the first support portion by a predetermined short distance toward a position that does not interfere with the above, the gantry is further intermittently moved in the predetermined direction, and in the intermittent movement of the first support portion, The first support portion is moved in the first direction along the long axis with respect to the second support portion, and the top plate is moved in the second direction with respect to the first support portion. ,
Sleeper device.