JP2024110038A - X-ray computed tomography equipment - Google Patents

Abstract

To secure accuracy of an imaging position, and prevent interference between a trestle body and a floor surface.SOLUTION: An X-ray CT apparatus includes: a stationary part having a stationary opening where a subject can be disposed for rotationally supporting a rotation part mounted with an X-ray tube; a stand having a movable part for supporting the stationary part movably in a vertical direction, and supporting the stationary part rotatably around a tilt shaft perpendicular to a vertical direction, which is provided on the floor surface; a first annular frame having a first opening opposed to the stationary part opening, which is connected to the stationary part and the movable part; a second annular frame having a second opening opposed to the first opening through the stationary part opening, which is connected to the movable part; a peripheral frame for connecting an outer periphery of the first annular frame and an outer periphery of the second annular frame; and an arm-shaped frame connected to the movable part for supporting the side face outside the peripheral frame on a stand side of the side face outside the peripheral frame at a plurality of connection points.SELECTED DRAWING: Figure 3

Description

The embodiments disclosed in this specification and the drawings relate to an X-ray computed tomography apparatus.

Conventionally, there is known an X-ray computed tomography (CT) apparatus capable of imaging a subject in a supine or upright position. Between imaging a subject in a supine position (hereinafter referred to as supine imaging) and imaging a subject in a standing position (hereinafter referred to as upright imaging), the X-ray CT apparatus has a mechanism for rotating a gantry body equipped with an imaging system. To perform upright imaging and supine imaging, the gantry body may be supported by a stand (also referred to as a stand) in a cantilevered manner.

At this time, it is important to suppress deformation of the fixed part that supports the rotating frame of the gantry body in order to ensure the accuracy of the shooting position and to prevent the lower end of the gantry body and the stand from interfering with the floor surface during upright shooting. In other words, unlike X-ray CT devices that support both sides of the gantry body or X-ray CT devices that can only perform upright or supine shooting, X-ray CT devices that support the gantry body with one arm require a structure that suppresses deformation of the fixed part while also suppressing deformation of the fixed part in both upright and supine shooting positions.

Figure 8 is a diagram showing an example of the inclination of the support surface (rotation support surface) RSS of the rotating part at the fixed part and the deflection of the opposite side of the stand ST (free end side FE of the rotating part support surface RSS) of the rotating part support surface RSS in a conventional mechanism that supports the pedestal body by a cantilever. In Figure 8, the vertical direction is shown as the Z axis direction, the horizontal direction is shown as the X direction, and the direction perpendicular to the Z direction and the X direction is shown as the Y axis direction. As shown in Figure 8, in the conventional mechanism that supports the pedestal body by a cantilever, it is assumed that the rotation support surface RSS will be tilted TL and the free end side FE of the rotating part support surface RSS will be deflected BD due to the weight of the pedestal body. Due to the inclination TL of the rotating part support surface RSS, an image that is intended to be taken horizontally with respect to the ground (floor surface) will be taken that is tilted with respect to the ground, and it is considered that the accuracy of the shooting position will deteriorate. Also, even when the rotating part support surface RSS remains horizontal and the free end FE bends BD, as the base body approaches the floor, the clearance between the base body and the floor, or between the base body and surrounding components, may decrease. This reduction in clearance may cause interference between the base body and the floor, or between the base body and several components.

Conventionally, in X-ray CT scanners having a mechanism for supporting the gantry body on a cantilever, reinforcing ribs are sometimes added to the bottom surface of the rotating support surface RSS in order to reduce the inclination of the rotating support surface RSS and the deflection (sagging) BD of the free end side FE of the rotating support surface RSS. In this case, a rib is required in the direction in which gravity is applied during both upright and prone position imaging, and this leads to an increase in the size of the gantry and ultimately a reduction in the imaging stroke (range of movement of the gantry body) during upright imaging.

US Patent Application Publication No. 2018/17747

One of the problems that the embodiments disclosed in this specification and the drawings attempt to solve is to realize an X-ray CT device that can prevent interference between the gantry body and the floor surface while ensuring the accuracy of the imaging position. However, the problems that the embodiments disclosed in this specification and the drawings attempt to solve are not limited to the above problem. Problems that correspond to the effects of each configuration shown in the embodiments described below can also be positioned as other problems.

The X-ray computed tomography apparatus according to this embodiment has a fixed section, a stand, a first annular frame, a second annular frame, an outer peripheral frame, and an arm-shaped frame. The fixed section has a fixed section opening in which a subject can be placed. The fixed section rotatably supports a rotating section on which an X-ray tube is mounted. The stand has a movable section that supports the fixed section movably in the vertical direction and supports the fixed section rotatably around a tilt axis perpendicular to the vertical direction. The stand is provided on a floor surface. The first annular frame has a first opening that faces the fixed section opening. The first annular frame is connected to the fixed section and the movable section. The second annular frame has a second opening that faces the first opening via the fixed section opening. The second annular frame is connected to the movable section. The outer peripheral frame connects the outer periphery of the first annular frame and the outer periphery of the second annular frame. The arm-shaped frame supports the outer side of the outer peripheral frame, the outer side of the outer peripheral frame that is on the stand side, at multiple connection points. The arm-shaped frame is connected to the movable part.

FIG. 1 is a diagram showing an example of the arrangement of an X-ray CT apparatus according to an embodiment. FIG. 2 is a perspective view showing an example of the positional relationship between the stand, a ring-shaped frame supporting a fixed portion, and an arm-shaped frame in a standing position shooting state in the embodiment. FIG. 3 is a perspective view showing an example in which a stand and a fixing portion are removed from FIG. 2 according to the embodiment. FIG. 4 is a perspective view showing an example of the positional relationship between the stand, a ring-shaped frame supporting a fixed portion, and an arm-shaped frame in a lying-down position imaging state according to the embodiment. FIG. 5 is a perspective view showing an example in which a stand and a fixing portion are removed from FIG. 4 in the embodiment. FIG. 6 is a perspective view showing an example of the positional relationship between the ring-shaped frame, the arm-shaped frame, and the hollowed-out portion in a standing position shooting state according to a modified example of the embodiment. FIG. 7 is a perspective view showing an example of the positional relationship between the ring-shaped frame, the arm-shaped frame, and the hollowed-out portion in a supine position imaging state according to a modified example of the embodiment. FIG. 8 is a diagram showing an example of the inclination of the support surface of the rotating part in the fixed part and the deflection of the support surface of the rotating part on the side opposite to the stand in a conventional mechanism that supports the pedestal body by cantilevering.

Below, an embodiment of an X-ray computed tomography apparatus (hereinafter referred to as an X-ray CT (computed tomography) apparatus) will be described with reference to the drawings. The X-ray CT apparatus according to this embodiment has a structure that allows the posture of the gantry to be changed between an upright imaging state in which the subject can be imaged in an upright position and a lying-down imaging state in which the subject can be imaged in a lying-down position, and further has a structure that supports the gantry body with a cantilever. In the following embodiments, parts with the same reference numbers perform similar operations, and duplicated descriptions will be omitted as appropriate.

(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 10, a bed 40, and a console 100. For example, the gantry 10 and the bed 40 are installed in a CT examination room, and the console 100 is installed in a control room adjacent to the CT examination room. The gantry 10, the bed 40, and the console 100 are connected to each other by wire or wirelessly so as to be able to communicate with each other. The gantry 10 and the bed 40 operate based on a user's operation via the console 100, or a user's operation via an operation unit provided on the gantry 10 or the bed 40. In this embodiment, an axial direction perpendicular to the floor surface, i.e., a vertical direction, and two directions perpendicular to the Z-axis direction and perpendicular to each other are defined as an X-axis direction and a Y-axis direction, respectively.

The gantry device 10 is a scanning device configured to perform X-ray CT imaging on a subject P in an upright or lying position. The console device 100 is a computer that controls the gantry device 10. The gantry device 10 includes a gantry (also called a gantry body or a gantry) 11, a stand (also called 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 P and an opening 15 into which the subject P can be inserted. The stand 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 be moved along the vertical direction. The stand 13 may also be called a stand unit.

The gantry 11 has an opening 15 that forms an imaging space for imaging the subject P. The gantry 11 is a substantially cylindrical structure in which the opening 15 is formed. As shown in FIG. 1, the gantry 11 houses an X-ray tube 17 and an X-ray detector 19 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 P 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. That is, the gantry 11 has an imaging system for imaging the subject P. The gantry 11 is supported by the stand 13 so as to be movable in the vertical direction along the stand 13. The gantry 11 is also supported by the stand 13 so as to be able to change the orientation of the opening 15 between the vertical direction and the horizontal direction. The orientation of the opening 15 corresponds to the direction along the rotation axis A1, for example, when the camera is in an upright shooting position. The rotation axis A1 is, for example, vertical when the camera is in an upright shooting position, and horizontal when the camera is in a lying down shooting position.

The gantry 11 has a fixed part 12 made of metal such as aluminum, a rotating part 21 rotatably supported by the fixed part 12 around a rotation axis A1 via bearings or the like when in a standing position imaging state, a ring-shaped frame (which may also be called a cylindrical frame) 14 supporting the fixed part 12, and an arm-shaped frame (not shown in FIG. 1) supporting the ring-shaped frame 14. The fixed part 12 has a fixed part opening in which the subject P can be placed, and rotatably supports the rotating part 21 carrying the X-ray tube 17. The fixed part opening corresponds to an opening 15 provided in the fixed part 12. Hereinafter, when focusing on the opening provided in the fixed part 12 with respect to the opening 15, the opening 15 will be referred to as the fixed part opening as necessary. The fixed part 12 is also referred to as, for example, a main frame or a fixed frame. The rotating part 21 is also referred to as a rotating frame 21. A ring-shaped electrode (not shown) is provided at the contact part between the main frame 12 and the rotating frame 21. A conductive slider (not shown) is attached to the contact portion of the main frame so that it makes sliding contact with the ring electrode. The ring-shaped frame 14 and the arm-shaped frame will be explained later.

The stand 13 is a base that supports the gantry 11 away from the floor surface. The stand 13 has a columnar shape, such as a cylindrical shape or a rectangular column shape. The stand 13 is attached, for example, to the side of the gantry 11. The stand 13 supports the gantry 11 in a vertically slidable manner with the rotation axis A1 of the opening 15 facing approximately perpendicular to the floor surface in order to perform X-ray CT imaging of the subject P in a seated or standing position. Specifically, the stand 13 is provided, for example, on the floor surface of an examination room in which the subject P is examined. The stand 13 also has a movable part 133 that supports the fixed part 12 so that it can move in the vertical direction and supports the fixed part 12 so that it can rotate around a tilt axis perpendicular to the vertical direction. The movable part 133 will be described later.

Typically, the stand 13 is provided on one side of the pedestal 11. Although the stand 13 has been described as having a columnar shape, this embodiment is not limited to this. For example, the stand 13 may have any shape, such as a U-shape, as long as it can support at least one side of the pedestal 11. Note that the stand 13 is not limited to being installed on the floor of the examination room, and one end of the stand 13 may be fixed to the floor of the examination room and the other end of the stand 13 may be fixed to the ceiling of the examination room.

The stand 13 supports the platform 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 stand 13 and the platform 11 are connected, for example, via a swivel bearing, so that the platform 11 can rotate around the tilt axis. Specifically, the stand 13 is provided with a linear guide 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 the movement control circuit 27. In addition, a gear that engages with a gear (internal teeth) in the swivel bearing is connected to the rotating shaft of the motor via various gears that generate a predetermined torque. The internal teeth in the swivel bearing rotate by driving a motor under the control of the movement control circuit 27. As a result, the platform 11 can rotate around the X-axis in FIG. 1 as the rotation axis and can move along the vertical direction. The linear guide and the swivel bearing correspond to the movable part 133 related to the movement of the base 11. In other words, the movable part 133 is mounted on the stand 13.

Under the control of the movement control circuit 27, the gantry movement mechanism 131 moves the block along a linear guide arranged along the vertical direction to move the gantry 11. This allows the gantry 11 to move up and down along the vertical direction. Note that the mechanism for moving the gantry 11 along 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 the internal teeth of the 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. The rotation of the gantry 11 by the rotation mechanism allows switching between an upright shooting state and a lying down shooting state.

For example, when performing supine imaging of the subject P, 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 P lies on the top board 43, the bed drive device 32 moves the top board 43, making it possible to perform supine imaging of the subject P in the same manner as with a normal X-ray CT device. When performing upright imaging of the subject P, 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 P stands directly under the opening 15, and the gantry 11 moves up and down to perform upright imaging. The structure of the gantry 11 in the upright imaging state and the supine imaging state will be explained later.

The X-ray tube 17 is a vacuum tube that generates X-rays by irradiating thermoelectrons from a cathode (filament) to an anode (target) by applying a high voltage from a high voltage generator 31 and supplying a filament current. X-rays are generated when the thermoelectrons collide with the target. The X-rays generated at the tube focus of the X-ray tube 17 are shaped into a cone beam, for example, via 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 thermoelectrons. Note that this embodiment can be applied to both a single-tube X-ray CT device and a so-called multi-tube X-ray CT device in which multiple pairs of X-ray tubes 17 and X-ray detectors 19 are mounted on a rotating frame 21.

The X-ray detector 19 detects the X-rays emitted from the X-ray tube 17 and passing through the subject P, and outputs an electrical signal corresponding to the amount of X-rays to the DAS 33. The X-ray detector 19 has, for example, a plurality of detector element rows in which a plurality of detector elements are arranged in the channel direction along one arc centered on the focal point of the X-ray tube 17. The X-ray detector 19 has, for example, a structure in which the detector element rows are arranged in a slice direction (row direction). The X-ray CT device 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 arrayed in a ring shape are fixed and only the X-ray tube 17 rotates around the subject P, and either type can be applied to this embodiment. For the sake of specificity, the following description will use a third-generation CT as an example of the X-ray CT device 1 of this embodiment.

The X-ray detector 19 is an indirect conversion type detector having, for example, a grid, a scintillator array, and an optical sensor array. The scintillator array has a plurality of scintillators, and the scintillator has a scintillator crystal that outputs 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 a function of absorbing scattered X-rays. The grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has a function of converting the amount of light from the scintillator into an electrical signal corresponding to the amount of light, and has an optical sensor such as a photomultiplier tube (PMT). The X-ray detector 19 may be a direct conversion type detector having a semiconductor element that converts the incident X-rays into an electrical signal. The X-ray detector 19 may also be a photon counting type X-ray detector. The X-ray detector 19 is an example of an X-ray detection unit.

The rotating frame 21 has an opening 15, and an X-ray tube 17 that generates X-rays is attached to it. Specifically, the rotating frame 21 is an annular frame that supports the X-ray tube 17 and the X-ray detector 19 facing each other and rotates the X-ray tube 17 and the X-ray detector 19 using a gantry control device 25 described below. The rotating frame 21 is rotatably supported on the main frame 12 via a support bearing. The rotating frame 21 receives power from a rotation drive device 23 under the control of the gantry control device 25 and rotates at a constant angular velocity around the rotation axis A1.

The rotating frame 21 further includes and supports the high voltage generator 31 and the 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 in which an opening 15 that forms the imaging space is formed. 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 a light-emitting diode (LED), for example, to a receiver having a photodiode provided in a non-rotating part of the gantry 10 (for example, the main frame 12), and is 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.

The rotation drive device 23 generates power to rotate 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 of the 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.

The gantry control device 25 controls the high voltage generator 31, the rotation drive device 23, the movement control circuit 27, the DAS 33, etc. according to commands from the console device 100. The gantry control device 25 has a function of receiving input signals from an input interface 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 an input signal 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 in the stand 13 of the gantry device 10 or in the console device 100. The function realized by the gantry control device 25 may be installed as a gantry control function in the processing circuit 107 in the console device 100.

The platform control device 25 has, as hardware resources, processing devices (processors) such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), and storage devices (memories) such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The platform control device 25 may also be implemented using an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), other complex programmable logic devices (CPLDs), or simple programmable logic devices (SPLDs).

The processing device realizes the above functions by reading and executing the program stored in the storage device. Note that instead of storing the program in the storage device, the processing device may be configured to directly incorporate the program into the circuitry. In this case, the processing device realizes the above functions by reading and executing the program embedded in the circuitry.

When a user instruction is input via the operation panel 29 or the like to realize an upright shooting state in which the orientation of the opening 15 is vertical, the movement control circuit 27 rotates the gantry 11 from the horizontal direction to the vertical direction by rotating the inner teeth of the swivel bearing of the gantry movement mechanism 131. When a user instruction is input via the operation panel 29 or the like to realize a lying-down shooting state in which the orientation of the opening 15 is horizontal, the movement control circuit 27 rotates the gantry 11 from the vertical direction to the horizontal direction by rotating the inner teeth of the swivel bearing of the gantry movement mechanism 131. When a tilt angle is input by the user via the operation panel 29 or the like, the movement control circuit 27 rotates the gantry 11 so as to realize the input tilt angle by rotating the inner teeth of the swivel bearing of the gantry movement mechanism 131.

When imaging in the supine position, if a command to move the gantry 11 is input by the user via the operation panel 29 or the like, the movement control circuit 27 moves the block of the gantry movement mechanism 131 to move the gantry 11 in the horizontal direction. When imaging in the upright position, if a command to move the gantry 11 is input by the user via the operation panel 29 or the like, the movement control circuit 27 moves the block of the gantry movement mechanism 131 to move the gantry 11 in the vertical direction.

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 the movement control unit. Note that in FIG. 1, the movement control circuit 27 is mounted on the stand 13, but it may be mounted on the platform 11 or the console device 100. In addition, the function realized by the movement control circuit 27 may be mounted on the processing circuit 107 or the platform control device 25 as a movement control function.

The operation panel 29 is realized by switch buttons, a touch pad for performing input operations by touching the operation surface, a touch panel display in which a display screen and a touch pad 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 to select, for example, an upright 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 stand 13.

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 12 side of the gantry 11.

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 bow-tie filter, and is a filter made of processed aluminum to have a predetermined target angle and a predetermined thickness.

The collimator (not shown) is a lead plate or the like that focuses the X-rays that have passed through the wedge into the X-ray irradiation range, and a slit is formed by combining multiple lead plates or the like.

The DAS 33 has an amplifier that performs an amplification process on 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.

The bed device 40 is a device for placing and moving the subject P to be scanned, and includes a base 41, a bed drive device 42, a top plate 43, and a top plate support frame 44. The base 41 is a housing that supports the top plate support frame 44 so that it can move in the vertical direction. The bed drive device 42 is a motor or actuator that moves the top plate 43 on which the subject P is placed in the longitudinal direction of the top plate 43. The bed drive device 42 moves the top plate 43 under the control of the console device 100. The top plate 43, which is provided on the upper surface of the top plate support frame 44, is a plate on which the subject P is placed. The bed drive device 42 may move the top plate support frame 44 in the longitudinal direction of the top plate 43 in addition to the top plate 43.

The console device 100 has 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).

The memory 101 is a storage device such as a hard disk drive (HDD), a solid state drive (SSD), or an integrated circuit storage device that stores various information. The memory 101 stores, for example, projection data and reconstructed image data. In addition to an HDD or SSD, the memory 101 may be a drive device that reads and writes various information between a portable storage medium such as a compact disc (CD), a digital versatile disc (DVD), or a flash memory, or a semiconductor memory element such as a random access memory (RAM). The storage area of the memory 101 may be in 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.

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

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

In this embodiment, the input interface 105 is not limited to having physical operation parts such as a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display. For example, an example of the input interface 105 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 107. The input interface 105 is also an example of an input unit. The input interface 105 may be provided in the pedestal device 10. The input interface 105 may be configured as a tablet terminal or the like that can wirelessly communicate with the console device 100 main body. The input interface 105 corresponds to an input unit.

The processing circuitry 107 controls the operation of the entire 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, processors such as a CPU, MPU, and GPU (Graphics Processing Unit), and memories such as ROM and RAM. The processing circuitry 107 executes a system control function 111, a preprocessing function 113, a reconstruction function 115, and an image processing function 117 by a processor that executes a program deployed in the memory.

The processing circuit 107 that executes the system control function 111, the preprocessing function 113, the reconstruction function 115, and the image processing function 117 corresponds to a system control unit, a preprocessing unit, an image generation unit, and an image processing unit. Note that the system control function 111, the preprocessing 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, the preprocessing function 113, the reconstruction function 115, and the image processing function 117.

The processing circuit 107 controls each function of the processing circuit 107 based on an input operation received from a user via the input interface 105 by 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 in the processing circuit 107, and controls each part of the X-ray CT device 1 according to the expanded control program. For example, the processing circuit 107 controls each function of the processing circuit 107 based on an input operation received from a user via the input interface 105.

The processing circuit 107 uses the preprocessing function 113 to generate data that has been subjected to 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.

The processing circuitry 107 generates CT image data by performing reconstruction processing using the filtered back projection method (FBP method) or the iterative reconstruction method, etc., on the projection data generated by the preprocessing function 113 using the reconstruction function 115. In other words, the reconstruction function 115 generates an image based on the output from the imaging system. The reconstruction function 115 stores the reconstructed CT image data in the memory 101.

The processing circuitry 107 uses the 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.

The structure of the ring-shaped frame 14 and the arm-shaped frame of the X-ray CT device 1 of this embodiment configured as above will be described with reference to Figs. 2 to 5. Fig. 2 is a perspective view showing an example of the positional relationship between the stand 13, the ring-shaped frame 14 supporting the fixed part 12, and the arm-shaped frame 16 in an upright position shooting state. Fig. 3 is a perspective view showing an example in which the stand 13 and the fixed part 12 have been removed from Fig. 2. Fig. 4 is a perspective view showing an example of the positional relationship between the stand 13, the ring-shaped frame 14 supporting the fixed part 12, and the arm-shaped frame 16 in a lying position shooting state. Fig. 5 is a perspective view showing an example in which the stand 13 and the fixed part 12 have been removed from Fig. 4.

As shown in Figures 2 and 4, the fixing portion 12 is fitted into a recess in the ring-shaped frame 14. At this time, the opening 15 faces an opening (hereinafter referred to as the first opening) 147 in the ring-shaped frame 14. As shown in Figures 3 and 5, the ring-shaped frame 14 has a first annular frame 141, a second annular frame 143, and an outer peripheral frame 145.

The first annular frame 141 has a first opening 147 facing the fixed part opening 15. As shown in Figs. 3 and 5, the size of the first opening 147 is larger than the fixed part opening 15, but is not limited to this. For example, the size of the first opening 147 may be approximately the same as the fixed part opening 15. The first annular frame 141 is connected to the fixed part 12 and the movable part 133. As a result, in the standing shooting state, the first annular frame 141 supports the lower surface of the fixed part 12 vertically upward as shown in Fig. 3.

The second annular frame 143 has a second opening that faces the first opening 147 through the fixing part opening 15, as shown in Figs. 2 to 5. The second opening corresponds to the inner space in the second annular frame 143. For example, when assembling the gantry 10, the fixing part 12 is fitted into the recess of the ring-shaped frame 14 through the second opening and connected to the first annular frame 141. The second annular frame 143 is connected to the movable part 133, as shown in Figs. 2 to 5. The second annular frame 143 corresponds to the other outer edge that faces the outer edge of the first annular frame 141.

As shown in Figures 2 to 5, the outer periphery frame 145 connects the outer periphery of the first annular frame 141 and the outer periphery of the second annular frame 143. The outer periphery frame 145 corresponds to a frame that forms the side of the ring-shaped frame 14. For convenience of explanation, the first annular frame 141, the second annular frame 143, and the outer periphery frame 145 are described as having different structures, but in manufacturing the ring-shaped frame 14, the first annular frame 141, the second annular frame 143, and the outer periphery frame 145 may be manufactured integrally.

As shown in Figs. 1 to 5, the stand 13 supports the fixed part 12 in a cantilevered state via the movable part 133, the first annular frame 141, the second annular frame 143, and the outer peripheral frame 145. Also, as shown in Figs. 2 to 5, the stand 13 rotates the orientation of the fixed part opening 15 between the vertical and horizontal directions via the movable part 133. Also, as shown in Figs. 2 and 4, when the fixed part opening 15 faces the floor surface and the second opening is located above the first opening 147, that is, in a standing shooting site, the second annular frame 143 supports the first annular frame 141 that supports the fixed part 12 by pulling the first annular frame 141 in the vertical direction via the outer peripheral frame 145.

As shown in Figs. 2 to 5, the arm-shaped frame 16 supports the outer side of the outer peripheral frame 145, the outer side of the outer peripheral frame 145 that is related to the stand 13, at multiple connection points. For example, the arm-shaped frame 16 continuously supports the outer side of the outer peripheral frame 145 that is related to the stand 13. The arm-shaped frame 16 is connected to the movable part 133. As shown in Figs. 2 to 5, the arm-shaped frame 16 supports the outer peripheral frame 145, which is connected to the first annular frame 141 that supports the fixed part 12, by sandwiching it at multiple connection points. For example, the arm-shaped frame 16 supports the outer peripheral frame 145 by sandwiching it symmetrically from the outside, centered on the connection point with the movable part 133.

The X-ray CT apparatus 1 according to the embodiment described above has a fixed part opening 15 in which a subject P can be placed, a fixed part 12 that rotatably supports a rotating part 21 on which an X-ray tube 17 is mounted, a movable part 133 that supports the fixed part 12 so that it can move in the vertical direction and rotatably supports the fixed part 12 around a tilt axis perpendicular to the vertical direction, a stand 13 that is provided on a floor surface, a first annular frame that has a first opening 147 facing the fixed part opening 15 and is connected to the fixed part 12 and the movable part 133, The arm 141 has a second annular frame 143 that has a second opening that faces the first opening 147 through the fixed part opening 15 and is connected to the movable part 133, a peripheral frame 145 that connects the outer periphery of the first annular frame 141 to the outer periphery of the second annular frame 143, and an arm-shaped frame 16 that supports the outer side of the peripheral frame 145 that is on the stand 13 side at multiple connection points and is connected to the movable part 133.

The stand 13 in the X-ray CT device 1 according to the embodiment supports the fixed part 12 in a cantilevered state via the movable part 133, the first annular frame 141, the second annular frame 143, and the outer peripheral frame 145, and the stand 13 rotates the orientation of the fixed part opening 15 between the vertical and horizontal directions via the movable part 133.

In the X-ray CT apparatus 1 according to the embodiment, when the fixed part opening 15 faces the floor of the examination room and the second opening is located above the first opening 147, the second annular frame 143 supports the first annular frame 141 that supports the fixed part 12 by pulling the first annular frame 141 vertically via the outer peripheral frame 145. In the X-ray CT apparatus 1 according to the embodiment, the arm-shaped frame 16 supports the outer peripheral frame 145 connected to the first annular frame 141 that supports the fixed part 12 by clamping it at multiple connection points.

For these reasons, according to the X-ray CT device 1 of the embodiment, the arm-shaped frame 16 can suppress tilting of the rotating part support surface in the fixed part 12. Also, according to the X-ray CT device 1 of the embodiment, as shown in Figs. 2 and 3, in the upright shooting state, the outer peripheral frame 145 can be supported at the midpoint between the stand 13 side of the fixed part 12 and the side opposite the stand 13 side of the fixed part 12. That is, according to the X-ray CT device 1 of the embodiment, in the upright shooting state, the ring-shaped frame 14 is supported at least at three points, the movable part 133 (tilt fixed surface) and the two support points of the arm-shaped frame 16, thereby suppressing tilting of the rotating part support surface in the fixed part 12.

In addition, with the X-ray CT device 1 according to the embodiment, as shown in Figs. 4 and 5, in the supine position imaging state, the lower side of the fixed part 12 is supported by the lower part (lower arm) of the arm-shaped frame 16, while the fixed part 12 is pulled up by the upper part (upper arm) of the arm-shaped frame 16, thereby preventing the fixed part 12 from being deformed by gravity.

In addition, according to the X-ray CT device 1 of the embodiment, the ring-shaped frame 14 allows the load that causes the deflection of the free end side of the rotation support surface to escape along the cylindrical surface (outer peripheral frame 145) of the ring-shaped frame 14, thereby suppressing the deflection of the fixed part 12. Furthermore, according to the X-ray CT device 1 of the embodiment, no structures are required on the free end side of the ring-shaped frame 14 or on the outside of the arm-shaped frame 16, and the rigidity of the cantilever-supported gantry 11 can be reinforced without changing the thickness of the gantry 11.

As described above, according to the X-ray CT device 1 of the embodiment, the frame structure using the ring-shaped frame 14 and the arm-shaped frame 16 can suppress deformation of the gantry 11 without changing the thickness of the gantry 11 along the direction perpendicular to the fixed part opening 15. In other words, according to the X-ray CT device 1 of the embodiment, the action of the ring-shaped frame 14 and the arm-shaped frame 16 ensures positional accuracy during imaging in both the upright imaging state and the lying-down imaging state, and suppresses bending and sagging that cause interference between the gantry 11 and the floor of the examination room.

As shown in FIG. 8, in the conventional method, a large displacement occurs due to the tilt of the rotating part support surface RSS. In contrast, in the X-ray CT device 1 according to the present embodiment, the tilt of the fixed part 12 can be suppressed by adding the arm-shaped frame 16. For example, with the X-ray CT device 1 according to the embodiment, the displacement of the fixed part 12 can be reduced to about 1.0% compared to the conventional method due to the action of the arm-shaped frame 16.

In addition, in the X-ray CT device 1 according to this embodiment, a ring-shaped frame 14 is further added, so that deflection on the free end side of the rotating part support surface can be suppressed. Furthermore, according to the X-ray CT device 1 according to this embodiment, it is possible to reinforce the rigidity of the gantry 11 without increasing the thickness of the gantry 11, making it possible to save space in the gantry 11 and ensure a stroke when shooting in a standing position (such as shooting at the feet of the subject P when standing).

(Modification)
This modification aims to reduce the weight of at least one of the first annular frame 141 and the outer peripheral frame 145. Specifically, at least one of the first annular frame 141 and the outer peripheral frame 145 has a plurality of lightening portions except for a plurality of connection points where the outer peripheral frame 145 and the arm-shaped frame 16 are connected. For example, the portion except for the plurality of connection points is located in an area opposite to the stand 13 side in at least one of the first annular frame 141 and the outer peripheral frame 145. In other words, the portion except for the plurality of connection points, i.e., the lightening portion, is located on the free end side of the ring-shaped frame 14.

The multiple cutout portions correspond to holes (also called cutout holes) provided in at least one of the first annular frame 141 and the outer peripheral frame 145, for example. The multiple cutout portions may be thinner than the thickness of the portions corresponding to the multiple connection points. In this case, the multiple cutout portions are realized by various cutout structures such as a rigid frame structure, a truss structure, a honeycomb structure, etc. The cutout structure is not limited to a rigid frame structure, a truss structure, a honeycomb structure, etc., and may be realized by other structures.

Figure 6 is a perspective view showing an example of the positional relationship between the ring-shaped frame 14, the arm-shaped frame 16, and the cutout portion 149 in an upright shooting state. Figure 7 is a perspective view showing an example of the positional relationship between the ring-shaped frame 14, the arm-shaped frame 16, and the cutout portion 149 in a lying-down shooting state. The cutout portion 149 shown in Figures 6 and 7 is shown as a hole provided on the free end side of the ring-shaped frame 14.

In the X-ray CT device 1 according to the modified embodiment described above, at least one of the first annular frame 141 and the outer peripheral frame 145 has a plurality of lightening portions 149 in a portion excluding the plurality of connection points. For example, the plurality of lightening portions 149 in the X-ray CT device 1 according to the modified embodiment are located in an area opposite the stand 13 side in at least one of the first annular frame 141 and the outer peripheral frame 145. The plurality of lightening portions 149 in the X-ray CT device 1 according to the modified embodiment correspond to holes provided in at least one of the first annular frame 141 and the outer peripheral frame 145. Note that the plurality of lightening portions 149 in the X-ray CT device 1 according to the modified embodiment may be thinner than the thickness of the portion corresponding to the plurality of connection points.

For these reasons, according to the X-ray CT device 1 of the modified embodiment, the first annular frame 141 and the second annular frame 143 corresponding to the surface to which the rotating part 21 is fixed are connected via the outer peripheral frame 145 along the thickness direction of the gantry 11, so that the load can be transmitted to the movable part 133 (tilt fixing surface) via members other than the multiple lightening portions 149 in the outer peripheral frame 145. For this reason, as shown in Figs. 6 and 7, by providing a lightening structure in the first annular frame 141 and the outer peripheral frame 145, the deflection of the free end caused by the weight of the arm-shaped frame 16 and the ring-shaped frame 14 in the structure (the free end side of the ring-shaped frame 14) beyond the multiple support points of the ring-shaped frame 14 by the arm-shaped frame 16 can be further reduced by the lightening caused by the lightening portion 149. Other effects of this modified embodiment are the same as those of the embodiment, so a description thereof will be omitted.

According to at least one of the embodiments and modified examples described above, it is possible to realize an X-ray CT device 1 that can prevent interference between the gantry body 11 and the floor surface while ensuring the accuracy of the imaging position.

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 within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

1 X-ray CT device 10 Mount device 11 Mount (gantry)
12 Fixed part (main frame, fixed frame)
13 Stand (support)
14 Ring-shaped frame 15 Opening (fixing part opening)
16 Arm-shaped frame 17 X-ray tube 19 X-ray detector 21 Rotating frame 23 Rotation drive device 25 Frame control device 27 Movement control circuit 29 Operation panel 31 High voltage generator 33 DAS (Data Acquisition System)
REFERENCE SIGNS LIST 100 Console device 101 Memory 103 Display 105 Input interface 107 Processing circuit 111 System control function 113 Pre-processing function 115 Reconstruction function 117 Image processing function 131 Frame moving mechanism 133 Movable part 141 First annular frame 143 Second annular frame 145 Peripheral frame 147 First opening 149 Hollowed-out portion

Claims (8)

a fixed part having an opening in which a subject can be placed and rotatably supporting a rotating part having an X-ray tube mounted thereon;
a stand provided on a floor surface, the stand having a movable part supporting the fixed part so as to be movable in a vertical direction and supporting the fixed part so as to be rotatable about a tilt axis perpendicular to the vertical direction;
a first annular frame having a first opening facing the fixed portion opening and connected to the fixed portion and the movable portion;
a second annular frame having a second opening facing the first opening with the fixed portion opening interposed therebetween and connected to the movable portion;
an outer periphery frame connecting an outer periphery of the first annular frame and an outer periphery of the second annular frame;
an arm-shaped frame that supports an outer side surface of the outer peripheral frame that is connected to a stand at a plurality of connection points and is connected to the movable part;
An X-ray computed tomography apparatus comprising: the stand supports the fixed portion in a cantilever state via the movable portion, the first annular frame, the second annular frame, and the outer peripheral frame,
The stand rotates the orientation of the fixed portion opening between the vertical direction and the horizontal direction via the movable portion.
2. The X-ray computed tomography apparatus according to claim 1. When the fixing portion opening faces the floor surface and the second opening is located above the first opening, the second annular frame supports the first annular frame that supports the fixing portion by pulling the first annular frame in the vertical direction via the outer circumferential frame.
3. An X-ray computed tomography apparatus according to claim 2. the arm-shaped frame supports the outer circumferential frame connected to the first annular frame supporting the fixed portion by sandwiching the outer circumferential frame at the plurality of connection points;
2. The X-ray computed tomography apparatus according to claim 1. At least one of the first annular frame and the outer peripheral frame has a plurality of hollowed-out portions except for the plurality of connection points.
5. An X-ray computed tomography apparatus according to claim 1. The plurality of hollowed-out portions are located in an area of at least one of the first annular frame and the outer peripheral frame opposite to the stand side.
6. An X-ray computed tomography apparatus according to claim 5. The plurality of hollowed-out portions correspond to holes provided in at least one of the first annular frame and the outer peripheral frame.
6. An X-ray computed tomography apparatus according to claim 5. The thickness of the plurality of hollowed-out portions is thinner than the thickness of the portions corresponding to the plurality of connection points.
6. An X-ray computed tomography apparatus according to claim 5.

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