X-ray computed tomography apparatus and movement control method

Abstract

To provide a compact X-ray CT apparatus capable of performing standing position imaging and lying position imaging.SOLUTION: An X-ray CT apparatus includes a gantry, a support, a top plate, a top plate moving mechanism, and a movement control unit. The gantry has an imaging system for imaging a subject and an opening into which the subject can be inserted. The support supports the gantry such that the gantry is movable in a vertical direction and such that a direction of the opening is changeable between the vertical direction and a horizontal direction. The top plate can place the subject thereon and can be inserted into the opening. The top plate moving mechanism is provided in the opening of the gantry and moves the top plate. When the direction of the opening is the vertical direction, the movement control unit controls the top plate moving mechanism so as to move the top plate in a direction opposite a moving direction of the gantry in accordance with the movement of the gantry along the vertical direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to an X-ray computed tomography apparatus and a movement control method. [Background technology]

[0002] Conventionally, there has been known an X-ray computed tomography (CT) apparatus capable of imaging a subject in either a supine or upright position. The X-ray CT apparatus has a mechanism for rotating a gantry body equipped with an imaging system between imaging a subject in a supine position (hereinafter referred to as supine imaging) and imaging a subject in an upright position (hereinafter referred to as upright imaging). X-ray CT apparatuses capable of performing both supine and upright imaging include, for example, a movable bed-based type in which the top plate can be used only during supine imaging, and a movable gantry-based type in which the gantry moves during both upright and supine imaging, but the top plate is fixed.

[0003] In either type, a mobile base is required to move the bed or gantry, which results in a problem of increased size for the X-ray CT system. As the size of the X-ray CT system increases, a larger installation space is also required, making it impossible to install the system in a conventional CT examination room. For this reason, one method of miniaturizing an X-ray CT system capable of performing both supine and upright position imaging is to install a tabletop on the gantry. However, in this case, the tabletop also moves up and down as the gantry moves during upright position imaging, causing the tabletop to come into contact with the ceiling or floor of the CT examination room, resulting in an obstruction. Therefore, there is a problem that the tabletop must be removed from the gantry when performing upright position imaging. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-77322 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to realize a compact X-ray CT device that can perform upright and supine position imaging. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0006] The X-ray computed tomography apparatus according to this embodiment includes a gantry, a support column, a top, a top movement mechanism, and a movement control unit. The gantry includes an imaging system for imaging a subject and an opening through which the subject can be inserted. The support column supports the gantry so that the gantry can be moved along the vertical direction and the orientation of the opening can be changed between the vertical direction and the horizontal direction. The top is capable of placing the subject and being inserted into the opening. The top movement mechanism is provided in the opening of the gantry and moves the top. The movement control unit controls the top movement mechanism to move the top in a direction opposite to the movement direction of the gantry in response to movement of the gantry along the vertical direction when the orientation of the opening is in the vertical direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the arrangement of an X-ray CT apparatus according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing a state of the gantry device in a standing mode according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing a state of the gantry device in a supine position mode according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the YZ cross section of the gantry as viewed from the X axis in the supine position mode according to the embodiment. [Figure 5]FIG. 5 is a cross-sectional view of the YZ cross section of the gantry as viewed from the X axis in the supine position mode according to the embodiment. [Figure 6] FIG. 6 is a perspective view showing a state of the gantry device in a supine position mode according to the embodiment. [Figure 7] FIG. 7 is a flowchart showing an example of a procedure of a movement control process according to the embodiment. [Figure 8] FIG. 8 is a cross-sectional view of the YZ cross section of the gantry as viewed from the X axis in the standing mode according to the embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a procedure for a movement control process according to a modified example of the embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a top plate moved to a predetermined position according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of an X-ray computed tomography apparatus (hereinafter referred to as an X-ray CT (computed tomography) apparatus) and a movement control method will be described with reference to the drawings. The X-ray CT apparatus according to this embodiment has a structure that can change the posture of the gantry between an upright position imaging state in which a subject can be imaged in an upright position and a prone position imaging state in which a subject can be imaged in a prone position. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate.

[0009] (Embodiment) FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus 1 according to an embodiment. As shown in FIG. 1, the X-ray CT apparatus 1 includes a gantry device 10 and a console device 100. For example, the gantry device 10 is installed in a CT examination room, and the console device 100 is installed in a control room adjacent to the CT examination room. The gantry device 10 and the console device 100 are connected to each other by wire or wirelessly so that they can communicate with each other. In this embodiment, an axial direction perpendicular to the floor surface, i.e., the vertical direction, is defined as the Z-axis direction, and two directions perpendicular to the Z-axis direction and perpendicular to each other are defined as the X-axis direction and the Y-axis direction, respectively.

[0010] The gantry 10 is a scanning device configured to perform X-ray CT imaging on a subject in an upright or recumbent position. The console device 100 is a computer that controls the gantry 10. The gantry 10 includes a gantry (also referred to as a gantry) 11, a support 13, a rotation drive device 23, and a gantry control device 25. The gantry 11 has an imaging system for imaging the subject and an opening 15 through which the subject can be inserted. The support 13 supports the gantry 11 so that the orientation of the opening 15 can be changed between the vertical and horizontal directions and so that the gantry 11 can move along the vertical direction. Note that in FIG. 1 , the gantry 11 is supported by the support 13 as a cantilever beam, but this is not limiting. For example, the gantry 11 may be supported by multiple support columns (e.g., two support columns). The support column 13 may be referred to as a support section.

[0011] The gantry 11 has an opening 15 that forms an imaging space for imaging the subject. The gantry 11 is a substantially cylindrical structure with the opening 15 formed therein. As shown in FIG. 1 , the gantry 11 houses an X-ray tube 17 and an X-ray detector 19 that are arranged to face each other across the opening 15. The X-ray tube 17 and the X-ray detector 19 are included in an imaging system for imaging the subject in this embodiment. The imaging system may further include a data acquisition circuit (hereinafter referred to as a DAS (Data Acquisition System)) 33, a high-voltage generator 31, a collimator, a wedge, and the like. In other words, the gantry 11 has an imaging system for imaging the subject. The gantry 11 is supported by the support 13 so as to be movable in the vertical direction along the support 13. The gantry 11 is also supported by the support 13 so as to change the orientation of the opening 15 between the vertical and horizontal directions. The orientation of the opening 15 corresponds to, for example, the direction in which the top board 30 is inserted into the opening 15, in other words, the direction along the rotation axis A1.

[0012] The base 11 has a main frame (not shown) made of metal such as aluminum, and a rotating frame 21 rotatably supported by the main frame via bearings or the like around a rotation axis A1. A ring-shaped electrode (not shown) is provided at the contact point between the main frame and the rotating frame 21. A conductive slider (not shown) is attached to the contact point of the main frame so as to make sliding contact with the ring-shaped electrode.

[0013] The support pillar 13 is a base that supports the gantry 11 at a distance from the floor surface. The support pillar 13 has a columnar shape such as a cylindrical or rectangular pillar shape. The support pillar 13 is formed of any material such as plastic or metal. The support pillar 13 is attached to the side of the gantry 11, for example. The support pillar 13 supports the gantry 11 so that the rotation axis A1 of the opening 15 is oriented approximately perpendicular to the floor surface and can slide in the vertical direction in order to perform X-ray CT imaging of a subject in a sitting or standing position.

[0014] Typically, the support pillar 13 is provided on one side of the gantry 11. However, this embodiment is not limited to this. For example, two support pillars 13 may be connected to both sides of the gantry 11. That is, at least one support pillar 13 supports the gantry 11 so that it can move in the vertical direction. Furthermore, although the support pillar 13 has been described as having a columnar shape, this embodiment is not limited to this. For example, the support pillar 13 may have any shape, such as a U-shape, as long as it can support at least one side of the gantry 11.

[0015] The support 13 supports the gantry 11 so that the rotation axis A1 can rotate between the vertical and horizontal directions around a horizontal axis (hereinafter referred to as the tilt axis) parallel to the floor surface. The support 13 and the gantry 11 are connected via, for example, a swivel bearing or the like so that the gantry 11 can rotate around the tilt axis. Specifically, a linear guide is provided on the support 13 along the vertical direction. A swivel bearing is provided on a block that can move along the linear guide. The block moves along the linear guide by driving a motor under the control of a movement control circuit 27. Furthermore, a gear that engages with a gear (internal teeth) on the swivel bearing is connected to the rotating shaft of the motor via various gears that generate a predetermined torque. The internal teeth on the swivel bearing rotate by driving a motor under the control of the movement control circuit 27. As a result, the gantry 11 can rotate around the X-axis in FIG. 1 as a rotation axis and move along the vertical direction. The linear guide and the swivel bearing correspond to a gantry movement mechanism 131 for moving the gantry 11. That is, the gantry movement mechanism 131 is mounted on the support 13.

[0016] The gantry movement mechanism 131 moves the gantry 11 by moving a block along a linear guide arranged in the vertical direction under the control of the movement control circuit 27. This allows the gantry 11 to move up and down in the vertical direction. Note that the mechanism for moving the gantry 11 in the vertical direction is not limited to a linear guide, and may be realized by a known mechanism such as a rack and pinion. Also, under the control of the movement control circuit 27, the gantry movement mechanism 131 rotates the gantry 11 between the horizontal and vertical directions by rotating internal teeth in a swivel bearing. Note that the rotation mechanism for rotating the gantry 11 is not limited to a swivel bearing, and may be realized by a known mechanism. Rotation of the gantry 11 by the rotation mechanism enables switching between an upright position imaging state (which may be referred to as the upright mode) and a supine position imaging state (which may be referred to as the supine mode), i.e., switching between the upright mode and the supine mode.

[0017] For example, when performing imaging of a subject in a supine position, the gantry movement mechanism 131 rotates the gantry 11 under the control of the movement control circuit 27 so that the opening 15 is vertical. After the subject lies on the top board 30, the top board 30 is moved horizontally by the top board movement mechanism 35 described below, thereby enabling imaging of the subject in a supine position, as with a normal X-ray CT device. When performing imaging of a subject in an upright position, the rotation mechanism in the gantry movement mechanism 131 rotates the gantry 11 under the control of the movement control circuit 27 so that the opening 15 is horizontal. The subject stands with their back against the top board 30, and the gantry 11 moves up and down to perform imaging in the upright position.

[0018] 2 is a perspective view showing the state of the gantry device 10 in the standing mode. As shown in FIG. 2, in the standing mode, the tabletop 30 is supported by the gantry 11 via the tabletop moving mechanism 35 in an upright state passing through the opening 15.

[0019] 3 is a perspective view showing the state of the gantry device 10 in the supine mode. As shown in Fig. 3, in the supine mode, the tabletop 30 is supported in a horizontal position by the gantry 11 via the tabletop movement mechanism 35. At this time, the tabletop 30 is freely movable along the longitudinal direction of the tabletop 30 under the control of the movement control circuit 27.

[0020] Fig. 4 is a cross-sectional view of the YZ cross section of the gantry 11 in the supine mode, as viewed from the X axis. The double-headed arrow HLM shown in Fig. 4 indicates the movement direction of the top 30 along the longitudinal axis of the top 30. As shown in Fig. 4, the top 30 on which the subject P is placed can be moved horizontally along the Y axis by driving the top movement mechanism 35 under the control of the movement control circuit 27, in accordance with the imaging protocol for imaging the subject P in the supine position.

[0021] The X-ray tube 17 is a vacuum tube that generates X-rays by irradiating thermions from a cathode (filament) toward an anode (target) when a high voltage is applied from a high voltage generator 31 and a filament current is supplied. X-rays are generated when thermions collide with the target. The X-rays generated at the tube focus of the X-ray tube 17 are shaped into a cone beam via, for example, a collimator and irradiated onto the subject P. For example, the X-ray tube 17 may be a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermions. Note that this embodiment can be applied to both a single-tube X-ray CT apparatus and a so-called multi-tube X-ray CT apparatus in which multiple pairs of X-ray tubes 17 and X-ray detectors 19 are mounted on a rotating frame 21.

[0022] The X-ray detector 19 detects X-rays emitted from the X-ray tube 17 and passing through the subject P, and outputs an electrical signal corresponding to the X-ray dose to the DAS 33. The X-ray detector 19 has, for example, multiple detector element rows, in which multiple detector elements are arranged in the channel direction along an arc centered on the focal point of the X-ray tube 17. The X-ray detector 19 has, for example, a structure in which multiple detector element rows are arranged in the slice direction (row direction). Note that the X-ray CT apparatus 1 includes a rotate / rotate type (third generation CT) in which the X-ray tube 17 and the X-ray detector 19 rotate together around the subject P, and a stationary / rotate type (fourth generation CT) in which a large number of X-ray detector elements arranged in a ring shape are fixed and only the X-ray tube 17 rotates around the subject P, and either type is applicable to this embodiment. For the sake of specificity, the X-ray CT apparatus 1 of this embodiment will be described below using a third generation CT as an example.

[0023] The X-ray detector 19 is an indirect conversion detector having, for example, a grid, a scintillator array, and a photosensor array. The scintillator array has multiple scintillators, and the scintillators have scintillator crystals that output light with a photon amount corresponding to the amount of incident X-rays. The grid is arranged on the X-ray incident side of the scintillator array and has an X-ray shielding plate that has the function of absorbing scattered X-rays. The grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The photosensor array has the function of converting light from the scintillator into an electrical signal corresponding to the amount of light, and has a photosensor such as a photomultiplier tube (PMT). The X-ray detector 19 may be a direct conversion detector having a semiconductor element that converts incident X-rays into an electrical signal. The X-ray detector 19 may also be a photon counting X-ray detector. The X-ray detector 19 is an example of an X-ray detection unit.

[0024] The rotating frame 21 has an opening 15, and an X-ray tube 17 that generates X-rays is attached to the rotating frame 21. Specifically, the rotating frame 21 is an annular frame that supports the X-ray tube 17 and the X-ray detector 19 so that they face each other, and rotates the X-ray tube 17 and the X-ray detector 19 using a gantry control device 25, which will be described later. The rotating frame 21 is rotatably supported on the main frame via support bearings. The rotating frame 21 receives power from a rotation drive device 23 under the control of the gantry control device 25, and rotates around a rotation axis A1 at a constant angular velocity.

[0025] The rotating frame 21 is equipped with and supports a high-voltage generator 31 and a DAS 33 in addition to the X-ray tube 17 and the X-ray detector 19. The rotating frame 21 is housed in a substantially cylindrical housing having an opening 15 that forms an imaging space. The central axis of the opening 15 coincides with the rotation axis A1 of the rotating frame 21. The detection data generated by the DAS 33 is transmitted by optical communication from a transmitter having, for example, a light-emitting diode (LED) to a receiver having a photodiode provided in a non-rotating part (e.g., the main frame) of the gantry 10, and then transferred to the console device 100. The method of transmitting the detection data from the rotating frame 21 to the non-rotating part of the gantry 10 is not limited to the optical communication described above, and any method of non-contact data transmission may be used.

[0026] The rotation drive device 23 generates power for rotating the rotating frame 21 under control of the gantry control device 25. The rotation drive device 23 generates power by driving at a rotation speed according to the duty ratio, etc., of a drive signal from the gantry control device 25. The rotation drive device 23 is realized by a motor such as a direct drive motor or a servo motor. The rotation drive device 23 is housed in the gantry 11, for example.

[0027] The gantry control device 25 controls the high-voltage generator 31, the rotation drive device 23, the movement control circuit 27, and the DAS 33 in accordance with commands from the console device 100. The gantry control device 25 has a function of receiving input signals from input interfaces attached to the console device 100 or the gantry device 10 and controlling the operation of the gantry device 10. For example, the gantry control device 25 receives input signals and controls the rotation of the rotating frame 21 or the tilt of the gantry device 10. The gantry control device 25 may be provided on the support 13 of the gantry device 10 or on the console device 100. The function realized by the gantry control device 25 may be implemented as a gantry control function in the processing circuit 107 of the console device 100.

[0028] The gantry control device 25 includes, as hardware resources, a processing device (processor) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) and a storage device (memory) such as a ROM (Read Only Memory) or RAM (Random Access Memory).The gantry control device 25 may also be realized by an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), another complex programmable logic device (CPLD), or a simple programmable logic device (SPLD).

[0029] The processing device realizes the above functions by reading and executing a program stored in the storage device. Note that instead of storing a program in the storage device, the processing device may be configured so that the program is directly embedded in the circuitry. In this case, the processing device realizes the above functions by reading and executing the program embedded in the circuitry.

[0030] The top 30, on which the subject P can be placed in the supine mode, can be inserted into the opening 15. The top 30 is supported by the gantry 11 via a top movement mechanism 35. Specifically, the top 30 is held by the top movement mechanisms 35 provided at both ends of the opening 15 of the gantry 11. That is, as shown in FIGS. 1 and 4 , the gantry 11 supports the top 30 via the top movement mechanism 35 at the inner wall portion that forms the opening 15. The top 30 can be moved by the top movement mechanism 35 along the direction in which the opening 15 penetrates. In other words, the top 30 and the gantry 11 are fixed via the top movement mechanism 35 so as to be slidable relative to the gantry 11 along the rotation axis A1 of the rotating frame 21 in the imaging system.

[0031] The tabletop moving mechanism 35 is provided in the opening 15 in the gantry 11. For example, the tabletop moving mechanism 35 is provided at both ends of the opening 15 as shown in FIG. 1. The tabletop moving mechanism 35 moves the tabletop 30 under the control of the movement control circuit 27. The tabletop moving mechanism 35 is configured, for example, by a roller guide or the like. The tabletop moving mechanism 35 can be realized by a configuration such as a friction drive or belt mechanism. Note that the tabletop moving mechanism 35 is not limited to a roller guide, friction drive, belt mechanism, or the like, and can be realized as appropriate by a known mechanism.

[0032] The top moving mechanism 35 may be mounted on a vertical movement mechanism. The vertical movement mechanism is, for example, mounted on the top moving mechanism 35 and provided on the gantry 11. The vertical movement mechanism is capable of moving the top 30 in a direction perpendicular to the surface of the top 30 on which the subject P is placed. For example, the vertical movement mechanism is realized by an actuator (for example, a piston type) that can move (push up) the rotation axis of a roller guide along the Y-axis direction. Note that the means for realizing the vertical movement mechanism is not limited to an actuator.

[0033] 5 is a cross-sectional view of the YZ cross section of the gantry 11 in the supine mode, viewed from the X axis. The double-headed arrow VLM in FIG. 5 indicates the movement direction of the tabletop 30 and the tabletop moving mechanism 35 along the vertical direction. As shown in FIG. 5, the up-down movement mechanism 34 may be realized by a hydraulic jack or the like that moves a partial exterior 36 of the gantry 11, on which the tabletop moving mechanism 35 is mounted, along the Z axis direction. The up-down movement mechanism 34 operates under the control of the movement control circuit 27 in accordance with instructions from the user, and moves the tabletop 30 up and down.

[0034] A left-right movement mechanism may also be provided between the top plate moving mechanism 35 and the top plate 30. For example, a top plate support member covering the bottom surface and side surfaces of the top plate 30 is provided on the underside and side surfaces of the top plate 30. The left-right movement mechanism includes a block, a ball screw, a motor, and a belt. The ball screw extends along the minor axis direction of the top plate 30. A block is attached to the ball screw. A top plate support member is connected to the block. The rotational force of the motor is transmitted to the Boyle screw via the belt. When the motor rotates below under the control of the movement control circuit 27, the rotational force of the motor is transmitted to the ball screw, which rotates the ball screw. As the ball screw rotates, the block moves along the minor axis direction of the top plate 30.

[0035] Fig. 6 is a perspective view showing the state of the gantry device 10 in the supine mode. The double-headed arrow LRM shown in Fig. 6 indicates the movement direction of the tabletop 30 along the short axis direction of the tabletop 30. The left-right movement mechanism supports the tabletop 30 so that it can move along the short axis direction LRM of the tabletop 30. The left-right movement mechanism operates under the control of the movement control circuit 27 in accordance with instructions from the user, and moves the tabletop 30 left and right.

[0036] When the orientation of the opening 15 is vertical (hereinafter referred to as upright position radiography), the movement control circuit 27 controls the top moving mechanism 35 to move the top 30 in the direction opposite to the moving direction of the gantry 11 in accordance with the movement of the gantry 11 along the vertical direction. Furthermore, during upright position radiography, the movement control circuit 27 controls the top moving mechanism 35 to move the top 30 in the direction opposite to the moving direction of the gantry 11 when the gantry 11 moves to the radiography position of the subject P. Furthermore, during upright position radiography, when a helical scan or a scanogram is performed as radiography for the subject P, the movement control circuit 27 controls the top moving mechanism 35 to move the top 30 in the direction opposite to the moving direction of the gantry 11. When moving the top 30 in the direction opposite to the moving direction of the gantry 11, the movement control circuit 27 controls the top moving mechanism 35 to move the top 30 in the opposite direction at the same moving speed as the moving speed of the gantry 11.

[0037] During upright position imaging, when a volume scan is performed as the imaging, the movement control circuit 27 stops the movement of the gantry 11 and the top 30. Furthermore, when the orientation of the opening 15 is horizontal, the movement control circuit 27 controls the top moving mechanism 35 to move the top 30 horizontally for imaging of the subject P. That is, when the gantry device 10 is in the supine position mode, the movement control circuit 27 controls the top moving mechanism 35 to move only the top 30 in response to a user instruction via the operation panel 29 or the like.

[0038] The movement control circuit 27 controls the gantry movement mechanism 131 and the top movement mechanism 35 for moving the gantry 11 so that the relative positional relationship between the support column 13, the gantry 11, and the top 30 becomes a predetermined positional relationship. The predetermined positional relationship is, for example, a position of the top 30 where the center position of the connection between the gantry 11 and the support column 13 is at the reference position BP shown in FIG. 2 and the two partial regions of the top 30 that protrude from both ends of the opening 15 of the gantry 11 to the outside of the opening 15 (hereinafter referred to as "both end protruding regions") are equal. In other words, the predetermined positional relationship corresponds to a positional relationship between the support column 13, the gantry 11, and the top 30 such that when the gantry 11 is rotated about the X-axis, the top 30 does not come into contact with the floor of the examination room. When the relative positional relationship reaches the predetermined positional relationship, the movement control circuit 27 controls the gantry movement mechanism 131 to rotate the orientation of the opening 15 between the horizontal and vertical directions.

[0039] The movement control circuit 27 is realized by the above-mentioned processor or the like. The processor that realizes the various movement control processes executed by the movement control circuit 27 corresponds to a movement control unit. In FIG. 1, the movement control circuit 27 is mounted on the support 13, but it may be mounted on the gantry 11 or the console device 100. Furthermore, the function realized by the movement control circuit 27 may be mounted on the processing circuit 107 or the gantry control device 25 as a movement control function.

[0040] The operation panel 29 is realized by switch buttons, a touchpad for performing input operations by touching the operation surface, a touch panel display in which a display screen and a touchpad are integrated, etc. The operation panel 29 converts input operations received from the user into electrical signals and outputs them to the gantry control device 25. The operation panel 29 accepts a selection operation for selecting, for example, a standing mode for imaging a subject P in an upright position, or a supine mode for imaging a subject P in a supine position. The operation panel 29 is provided, for example, on the support 13.

[0041] The high voltage generator 31 has electrical circuits such as a transformer and a rectifier, and generates a high voltage to be applied to the X-ray tube 17 and a filament current to be supplied to the X-ray tube 17. The high voltage generator 31 also controls the output voltage according to the X-rays emitted by the X-ray tube 17. The high voltage generator 31 may be of a transformer type or an inverter type. The high voltage generator 31 may be provided on the rotating frame 21 or on the main frame side of the gantry 11.

[0042] The wedge (not shown) is a filter for adjusting the amount of X-rays irradiated from the X-ray tube 17. Specifically, the wedge is a filter that transmits and attenuates the X-rays irradiated from the X-ray tube 17 so that the X-rays irradiated from the X-ray tube 17 to the subject P have a predetermined distribution. The wedge is, for example, a wedge filter or a bow-tie filter, and is a filter made of processed aluminum so as to have a predetermined target angle and a predetermined thickness.

[0043] The collimator (not shown) is a lead plate or the like for concentrating the X-rays transmitted through the wedge into an X-ray irradiation range, and a slit is formed by combining a plurality of lead plates or the like.

[0044] The DAS 33 has an amplifier that amplifies the electrical signals output from each X-ray detection element of the X-ray detector 19 and an A / D converter that converts the electrical signals into digital signals, and generates detection data. The detection data generated by the DAS 33 is transferred to the console device 100.

[0045] The console device 100 includes a memory 101, a display 103, an input interface 105, and a processing circuit 107. Data communication between the memory 101, the display 103, the input interface 105, and the processing circuit 107 is performed, for example, via a bus (BUS).

[0046] The memory 101 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit storage device that stores various types of information. The memory 101 stores, for example, projection data and reconstructed image data. In addition to an HDD or an SSD, the memory 101 may be a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc), or a flash memory, or a drive device that reads and writes various types of information from and to a semiconductor memory element such as a RAM (Random Access Memory). The storage area of ​​the memory 101 may be located within the console device 100 or in an external storage device connected via a network. The memory 101 also stores a control program according to this embodiment. The memory 101 stores volume data generated by a pre-scan or a main scan.

[0047] The display 103 displays various types of information. For example, the display 103 outputs medical images (CT images) generated by the processing circuitry 107, a GUI (Graphical User Interface) for receiving various operations from a user, and the like. For example, the display 103 may be a liquid crystal display (LCD), a cathode ray tube (CRT), an organic electroluminescence display (OLED), a plasma display, or any other display, as appropriate. The display 103 may also be provided on the gantry device 10. The display 103 may also be a desktop type, or may be configured as a tablet terminal or the like capable of wireless communication with the console device 100 main body. The display 103 corresponds to a display unit.

[0048] The input interface 105 accepts various input operations from a user, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuitry 107. For example, the input interface 105 accepts from the user acquisition conditions for acquiring projection data, reconstruction conditions for reconstructing CT images, image processing conditions for generating post-processed images from CT images, etc. As the input interface 105, for example, a mouse, keyboard, trackball, switch, button, joystick, touchpad, touch panel display, etc. can be used as appropriate.

[0049] In this embodiment, the input interface 105 is not limited to one having physical operation components such as a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display. For example, an example of the input interface 105 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs the electrical signal to the processing circuit 44. The input interface 105 is also an example of an input unit. The input interface 105 may also be provided in the gantry device 10. The input interface 43 may also be configured as a tablet terminal or the like that is capable of wireless communication with the console device 100 main body. The input interface 105 corresponds to the input unit.

[0050] The processing circuitry 107 controls the overall operation of the X-ray CT apparatus 1 in response to electrical signals of input operations output from the input interface 105. For example, the processing circuitry 107 has, as hardware resources, a processor such as a CPU, MPU, or GPU (Graphics Processing Unit) and memories such as ROM and RAM. The processing circuitry 107 executes a system control function 111, a pre-processing function 113, a reconstruction function 115, and an image processing function 117 using a processor that executes a program loaded in memory. The processing circuitry 107, which executes the system control function 111, the pre-processing function 113, the reconstruction function 115, and the image processing function 117, respectively, corresponds to a system control unit, a pre-processing unit, an image generation unit, and an image processing unit. Note that the system control function 111, the pre-processing function 113, the reconstruction function 115, and the image processing function 117 are not limited to being realized by a single processing circuit. A processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to realize the system control function 111, preprocessing function 113, reconstruction function 115, and image processing function 117, respectively.

[0051] The processing circuitry 107 controls each function of the processing circuitry 107 based on an input operation received from a user via the input interface 105 using the system control function 111. Specifically, the system control function 111 reads out a control program stored in the memory 101, expands it on the memory within the processing circuitry 107, and controls each unit of the X-ray CT apparatus 1 in accordance with the expanded control program. For example, the processing circuitry 107 controls each function of the processing circuitry 107 based on an input operation received from a user via the input interface 105.

[0052] The processing circuitry 107 generates data by using a preprocessing function 113, which performs preprocessing such as logarithmic conversion, offset correction, inter-channel sensitivity correction, and beam hardening correction on the detection data output from the DAS 33. Note that data before preprocessing is referred to as raw data, and data after preprocessing is referred to as projection data.

[0053] The processing circuitry 107 generates CT image data by using a reconstruction function 115 to perform reconstruction processing using a filtered back projection (FBP) method, an iterative reconstruction method, or the like on the projection data generated by the preprocessing function 113. That is, the reconstruction function 115 generates an image based on the output from the imaging system. The reconstruction function 115 stores the data of the reconstructed CT image in the memory 101.

[0054] The processing circuitry 107 uses an image processing function 117 to perform various image processing on the CT image reconstructed by the reconstruction function 115. For example, the image processing function 117 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 to generate a display image.

[0055] The movement control process executed by the X-ray CT apparatus 1 of this embodiment configured as described above will be described with reference to Fig. 7. The movement control process is to control the movement of various members related to the change in the posture of the gantry 11 between the standing mode and the lying mode, and the movement of the tabletop 30 accompanying the movement of the gantry 11 in the standing mode. Fig. 7 is a flowchart showing an example of the procedure of the movement control process according to this embodiment. For the sake of concreteness, the following description will be given assuming that an imaging protocol in the standing mode is set as a scan for the subject P.

[0056] (Movement control processing) (Step S701) If the state of the gantry 11 is not the upright position imaging state (upright position mode) (No in step S701), that is, if the state of the gantry 11 is the lying position imaging state (lying position mode), the process of step S702 is executed. If the state of the gantry 11 is the upright position imaging state (upright position mode) (Yes in step S701), that is, if the state of the gantry 11 is not the lying position imaging state (lying position mode), the process of step S704 is executed.

[0057] (Step S702) The movement control circuit 27 controls the gantry movement mechanism 131 and the top movement mechanism 35 so that the relative positional relationship between the support column 13, the gantry 11, and the top 30 becomes a predetermined positional relationship. That is, the processing in this step is repeated until the relative positional relationship reaches the predetermined positional relationship. Specifically, the movement control circuit 27 controls the gantry movement mechanism 131 until the center position of the connection between the gantry 11 and the support column 13 reaches the reference position BP. As a result, the gantry 11 moves to the reference position BP along the vertical direction of the support column 13. In addition, the movement control circuit 27 controls the top movement mechanism 35 until the protrusion areas at both ends become equal. As a result, the top 30 protrudes by the same amount from both ends of the opening 15 of the gantry 11.

[0058] (Step S703) The movement control circuit 27 rotates the gantry 11 so that it assumes an upright shooting state. Specifically, the movement control circuit 27 controls the gantry movement mechanism 131 so that the orientation of the opening 15 is horizontal, i.e., the rotation axis A1 is horizontal. As a result, the posture of the gantry 11 assumes an upright shooting state.

[0059] (Step S704) The movement control circuit 27 controls the gantry movement mechanism 131 to move the gantry 11 to the imaging position according to the set imaging protocol. In addition, the movement control circuit 27 controls the top movement mechanism 35 to move the top 30 in the direction opposite to the movement direction of the gantry 11 as the gantry 11 moves to the imaging position. Specifically, the movement control circuit 27 controls the top movement mechanism 35 to move the top 30 in the opposite direction at the same speed as the movement speed of the gantry 11, i.e., so that the top 30 does not move together with the gantry 11. In the processing of this step, the movement control circuit 27 controls the gantry movement mechanism 131 and the top movement mechanism 35 until the gantry 11 reaches the imaging position. Through the above processing, the gantry 11 reaches the imaging position.

[0060] Fig. 8 is a cross-sectional view of the YZ cross section of the gantry 11 as viewed from the X axis in the standing mode. As shown in Fig. 8, when the gantry 11 moves in the vertical downward direction GM, the tabletop 30 moves in the vertical upward direction TM at the same speed as the moving speed of the gantry 11. As shown in Fig. 8, since the tabletop 30 moves in the opposite direction to the moving direction of the gantry 11 at the same speed as the moving speed of the gantry 11, the tabletop 30 appears to be stationary from the viewpoint of the subject P who is in a standing position with his / her back leaning against the tabletop 30.

[0061] (Step S705) In response to a user instruction via the input interface 105, a scan of the subject P is started.

[0062] (Step S706) If the started scan is a helical scan (Yes in step S706), the process proceeds to step S707. If the started scan is a scanogram imaging, the process proceeds to step S707. If the started scan is not a helical scan (No in step S706), for example, if the started scan is a volume scan, the process proceeds to step S708.

[0063] (Step S707) The movement control circuit 27 controls the gantry movement mechanism 131 to move the gantry 11 in accordance with the set imaging protocol. In addition, the movement control circuit 27 controls the top movement mechanism 35 to move the top 30 in the direction opposite to the movement direction of the gantry 11 as the gantry 11 moves. As a result, when helical scan or scanogram imaging is performed, the movement control circuit 27 controls the top movement mechanism 35 to move the top 30 in the opposite direction at the same speed as the movement speed of the gantry 11. The control of the movement of the gantry 11 and the top 30 in this step is substantially similar to that in step S704, and therefore will not be described again.

[0064] (Step S708) The movement control circuit 27 stops the movement of the gantry 11 and the top 30. For example, when a volume scan is performed on the subject P, the movement control circuit 27 controls the gantry movement mechanism 131 to fix the gantry 11 at the imaging position, and controls the top movement mechanism 35 to fix the top 30 to the gantry 11. In other words, when a volume scan is performed, the gantry 11 is fixed to the support 13, and the top 30 is fixed to the gantry 11.

[0065] (Step S709) If the scan for the subject P is completed (Yes in step S709), the movement control process ends. If the scan for the subject P is not completed (No in step S709), the process from step S706 onwards is repeated.

[0066] The X-ray CT apparatus 1 according to the embodiment described above moves the gantry 11, which has an imaging system for imaging the subject P and an opening 15 through which the subject P can be inserted, in the vertical direction to the imaging position of the subject P in an upright imaging state where the subject P can be imaged in an upright position, and moves the top board 30, which is inserted into the opening 15 and attached to the gantry 11, in the direction opposite to the moving direction of the gantry 11 in accordance with the movement of the gantry 11. Furthermore, the X-ray CT apparatus 1 according to this embodiment moves the top board 30 at the same moving speed as the moving speed of the gantry 11. Furthermore, when the opening 15 is oriented horizontally, the X-ray CT apparatus 1 according to this embodiment moves the top board 30 in the horizontal direction for imaging the subject P in the supine position mode. Furthermore, the gantry 11 in the X-ray CT apparatus 1 according to this embodiment supports the top board 30 at inner wall portions that form the opening 15 (for example, at both ends of the opening 15 in the gantry 11). In addition, in the X-ray CT device 1 of the embodiment, the top plate 30 and the gantry 11 are fixed via a top plate moving mechanism 35 so as to be slidably movable relative to the gantry 11 along the direction of the rotation axis A1 of the rotating frame 21 in the imaging system of the gantry 11.

[0067] Furthermore, when the orientation of the opening 15 is vertical, the X-ray CT apparatus 1 according to the embodiment moves the top 30 in the direction opposite to the direction of movement of the gantry 11 when the gantry 11 moves to the imaging position of the subject P, and when the orientation of the opening 15 is vertical and a helical scan or scanogram imaging is performed as the imaging, moves the top 30 in the direction opposite to the direction of movement of the gantry 11, and when the orientation of the opening 15 is vertical and a volume scan is performed as the imaging, stops the movements of the gantry 11 and the top 30. Furthermore, the X-ray CT apparatus 1 according to the embodiment controls the gantry movement mechanism 131 and the top movement mechanism 32 related to the movement of the gantry 11 so that the relative positional relationship between the support column 13, the gantry 11, and the top 30 becomes a predetermined positional relationship, and when the relative positional relationship reaches the predetermined positional relationship, controls the gantry movement mechanism 131 to rotate the orientation of the opening 15 between the horizontal and vertical directions.

[0068] Furthermore, the X-ray CT apparatus 1 according to the embodiment may have a vertical movement mechanism 34 that can move the top 30 in a direction perpendicular to the surface of the top 30 on which the subject P is placed, and the vertical movement mechanism 34 is equipped with a top movement mechanism 35 and is provided on the gantry 11. Furthermore, the X-ray CT apparatus 1 according to the embodiment may be provided with a left-right movement mechanism between the top 30 and the top movement mechanism 35, for example, that supports the top 30 movably in the minor axis direction of the top 30.

[0069] For these reasons, in the past, when trying to move only the gantry 11 up and down, it was necessary to provide a mechanism for moving the gantry 11 up and down and a mechanism for fixing the top plate / bed to prevent the movement of the top plate 30 from following the up and down movement of the gantry 11. However, with the X-ray CT device 1 of this embodiment, instead of providing such a fixing mechanism, a mechanism for moving the top plate 30 relative to the gantry 11 is provided, thereby simplifying the structure related to the movement of the top plate 30 relative to the gantry 11.

[0070] That is, in the X-ray CT apparatus 1 capable of imaging the subject P in both the standing mode and the lying mode, imaging of the subject P in the standing position is possible without removing the tabletop 30 from the gantry 11, and imaging of the subject P in the lying position is possible with the tabletop 30 attached to the gantry 11. This allows the X-ray CT apparatus 1 to be made compact (small) without increasing its size, and the standing and lying position combined X-ray CT apparatus 1 can be installed in a room the same size as a normal CT examination room. Furthermore, with the X-ray CT apparatus 1, a bed moving base and a gantry moving base are not required, and the multifunctional X-ray CT apparatus 1 capable of realizing both the lying mode and the standing mode can be realized at low cost.

[0071] (Variation) The difference between this modified example and the embodiment is that one end of the top 30 has a support plate on which the soles of the feet of the subject P can be placed. That is, when the opening 15 is oriented vertically, a support plate capable of supporting the soles of the feet of the subject P is provided at one end of the top 30. In this modified example, when the opening 15 is oriented vertically, the movement control circuit 27 moves the top 30 vertically upward relative to the gantry 11 in accordance with the selection of an imaging protocol for the feet of the subject P, and then controls the top movement mechanism 35 to move the top 30 in the direction opposite to the movement direction of the gantry 11 when moving the gantry 11 to an imaging position for the feet of the subject P.

[0072] The movement control process in the modified example will be described below with reference to Fig. 9. Fig. 9 is a flowchart showing an example of the procedure of the movement control process according to the modified example of the embodiment.

[0073] (Movement control processing) (Step S901) An imaging protocol is selected for an examination on the subject P. The selection of the imaging protocol may be set by a user's instruction via the input interface 105 or the operation panel 29, or may be automatically selected based on an examination order output from a Radiology Information System (RIS) to the console device 100.

[0074] The processing in steps S902 to S904 is similar to the processing in steps S701 to S703, and therefore a description thereof will be omitted.

[0075] (Step S905) If the imaging region in the imaging protocol is the foot of the subject P (Yes in step S905), the process of step S906 is executed. If the imaging region in the imaging protocol is not the foot of the subject P (No in step S905), the process from step S704 onwards is executed.

[0076] (Step S906) After the soles of the subject P are placed on the support plate, the movement control circuit 27 moves the top board 30 vertically upward relative to the gantry 11 to a predetermined position. The predetermined position is, for example, a position where the imaging region can be scanned by the gantry 11 in the selected imaging protocol. The processing from step S906 onwards is similar to the processing from step S704 onwards, and therefore a description thereof will be omitted.

[0077] FIG. 10 is a diagram showing an example of the tabletop 30 that has been moved to a predetermined position PP. The tabletop 30 in FIG. 10 has moved slightly upward in the vertical direction compared to FIG. 2 to the predetermined position PP and then stopped. The gantry 11 shown in FIG. 10 has also been lowered to the imaging region SP. As described in step S704, the movement control circuit 27 controls the tabletop movement mechanism 35 to move the tabletop 30 in the direction opposite to the movement direction of the gantry 11 as the tabletop 11 moves to the imaging position SP, thereby enabling upright position imaging to be performed at the feet of the subject P, which is the imaging position SP.

[0078] The X-ray CT apparatus 1 according to the modified embodiment has a support plate 37 at one end of the tabletop 30 that can support the soles of the feet of the subject P when the opening 15 is oriented vertically. When the opening 15 is oriented vertically, the X-ray CT apparatus 1 according to the modified embodiment moves the tabletop 30 vertically upward relative to the gantry 11 in accordance with the selection of an imaging protocol for the feet of the subject P, and then moves the tabletop 30 in the opposite direction when the gantry 11 moves to an imaging position SP for the feet of the subject P.

[0079] For these reasons, according to the X-ray CT apparatus 1 of the modified embodiment, when imaging the feet of the subject P in a standing position, the top board 30 is raised slightly relative to the gantry 11 until the feet of the subject P are within the imaging range and then stopped, and then the top board 30 is moved in the opposite direction to the up and down speed of the gantry 11, thereby making it possible to image the feet of the subject P in a standing position. As a result, the present X-ray CT apparatus 1, which is a combined standing and lying position type and can be installed in a room of the same size as a normal CT examination room, can image the feet of the subject P while maintaining the same compactness as the embodiment.

[0080] Furthermore, the X-ray CT apparatus 1 according to the modified example of this embodiment can switch between the standing mode and the lying mode while the subject P is in contact with the support surface of the tabletop 30, thereby improving the throughput of the examination of the subject P and reducing the burden on the subject P and the user. Other effects are the same as those of the embodiment, and therefore will not be described.

[0081] When the technical ideas of the embodiments and the like are realized by a movement control method, the movement control method moves a gantry 11, which has an imaging system for imaging the subject P and an opening 15 into which the subject P can be inserted, in the vertical direction to an imaging position for the subject P in an upright imaging state, and moves a top board 30, which is inserted into the opening 15 and provided on the gantry 11, in the direction opposite to the moving direction of the gantry 11 in accordance with the movement of the gantry 11. The procedure and effects of the movement control process in the movement control method are similar to those of the embodiments and the like, and therefore will not be described again.

[0082] According to at least one of the embodiments and modifications described above, it is possible to realize a compact X-ray CT apparatus 1 that is capable of performing imaging in both upright and supine positions.

[0083] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0084] 1 X-ray CT device 10 Mounting device 11 Gantry 13 Posts 15 Aperture 17 X-ray tube 19 X-ray detector 21 Rotating Frame 23 Rotational drive unit 25 Mounting control device 27 Movement control circuit 29 Operation Panel 31 High voltage generator 33 DAS (Data Acquisition System) 34 Vertical movement mechanism 35 Top plate movement mechanism 36 Exterior 37 Support plate 100 Console device 101 Memory 103 Display 105 Input Interface 107 Processing Circuit 111 System Control Functions 113 Pre-processing function 115 Reconfiguration function 117 Image Processing Functions 131 Platform movement mechanism

Claims

1. a gantry having an imaging system for imaging a subject and an opening through which the subject can be inserted; a support column supporting the pedestal so that the pedestal can be moved along a vertical direction and the orientation of the opening can be changed between the vertical direction and a horizontal direction; a top plate on which the subject can be placed and which can be inserted into the opening; a top moving mechanism provided in the opening of the gantry and configured to move the top; a movement control unit that controls the top moving mechanism to move the top upward in the vertical direction in a direction opposite to the movement direction of the gantry in response to movement of the gantry along the downward vertical direction when the orientation of the opening is the vertical direction, and controls the top moving mechanism to move the top downward in the vertical direction in response to movement of the gantry along the upward vertical direction; An X-ray computed tomography apparatus comprising:

2. the movement control unit controls the tabletop movement mechanism to move the tabletop along the horizontal direction during the imaging when the orientation of the opening is in the horizontal direction.

2. The X-ray computed tomography apparatus according to claim 1.

3. the pedestal supports the tabletop via the tabletop moving mechanism at an inner wall portion that forms the opening.

3. An X-ray computed tomography apparatus according to claim 1.

4. a support plate that can support the soles of the subjects when the opening is oriented in the vertical direction is provided at one end of the tabletop; 4. An X-ray computed tomography apparatus according to claim 1.

5. When the orientation of the opening is the vertical direction, when the gantry is moved to an imaging position of the subject, the movement control unit: controlling the tabletop moving mechanism to move the tabletop upward in the vertical direction in response to movement of the gantry downward in the vertical direction; controlling the tabletop moving mechanism to move the tabletop downward in the vertical direction in response to movement of the gantry upward in the vertical direction; When the orientation of the opening is the vertical direction and helical scan or scanogram imaging is performed as the imaging, the movement control unit: controlling the tabletop moving mechanism to move the tabletop upward in the vertical direction in response to movement of the gantry downward in the vertical direction; controlling the tabletop moving mechanism to move the tabletop downward in the vertical direction in response to movement of the gantry upward in the vertical direction; When the orientation of the opening is the vertical direction and a volume scan is performed as the imaging, the movement control unit stops the movement of the gantry and the movement of the top plate.

5. An X-ray computed tomography apparatus according to claim 1.

6. When the orientation of the opening is the vertical direction, the movement control unit moves the top relative to the gantry in an upward direction in the vertical direction in accordance with a selection of an imaging protocol for the foot of the subject, and then controls the top movement mechanism to move the top upward in the vertical direction in accordance with the movement of the gantry along the downward direction in the vertical direction, in moving the gantry to an imaging position for the foot of the subject, and controls the top movement mechanism to move the top downward in the vertical direction in accordance with the movement of the gantry along the upward direction in the vertical direction.

5. The X-ray computed tomography apparatus according to claim 4.

7. The movement control unit controlling a gantry movement mechanism and a tabletop movement mechanism for moving the gantry so that the relative positional relationship between the support column, the gantry, and the tabletop is a predetermined positional relationship; When the relative positional relationship reaches the predetermined positional relationship, the gantry movement mechanism is controlled to rotate the orientation of the opening between the horizontal direction and the vertical direction.

7. An X-ray computed tomography apparatus according to claim 1.

8. the top plate and the gantry are fixed via the top plate moving mechanism so as to be slidable relative to the gantry along the direction of a rotation axis of a rotating frame in the imaging system; 8. An X-ray computed tomography apparatus according to claim 1.

9. a vertical movement mechanism that can move the top plate in a direction perpendicular to a surface of the top plate on which the subject is placed, The up-down movement mechanism is provided on the pedestal and includes the top plate movement mechanism.

9. An X-ray computed tomography apparatus according to claim 1.

10. a left-right movement mechanism that supports the tabletop movably in the minor axis direction of the tabletop is provided between the tabletop and the tabletop movement mechanism; 10. An X-ray computed tomography apparatus according to claim 1.

11. the movement control unit controls the tabletop movement mechanism so as to move the tabletop at the same movement speed as the movement speed of the gantry.

11. An X-ray computed tomography apparatus according to any one of claims 1 to 10.

12. In a standing position imaging state in which the subject can be imaged in an upright position, a gantry having an imaging system for imaging the subject and an opening into which the subject can be inserted is moved vertically downward to an imaging position of the subject; a top plate inserted into the opening and provided on the pedestal is moved upward in the vertical direction in accordance with the movement of the pedestal; A movement control method comprising:

Images