X-ray CT apparatus, control method, and control program

Abstract

To execute control with high safety.SOLUTION: An X-ray CT apparatus includes a scanner part, a support part, a selection part, and a control part. The scanner unit includes an imaging system. The support unit includes a moving mechanism of the scanner unit and supports the scanner unit. The selection part selects a unit for moving the scanner part according to an imaging mode based on the state of the subject. The control unit controls the unit in accordance with a driving condition for each imaging mode.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] In most X-ray CT scanners (X-ray computed tomography scanners), the subject is in a supine position on a bed, but upright X-ray CT scanners that can take images of subjects in an upright position are also in practical use. In addition, there are also upright / supine X-ray CT scanners that can switch between a mode for taking images of subjects in an upright position (upright imaging mode) and a mode for taking images of subjects in a supine position (supine imaging mode). In upright / supine X-ray CT scanners, the angle of the scanner can be changed to switch between taking images in a supine position and an upright position.

[0003] In X-ray CT systems that can be used in both upright and prone positions, the scanner unit has more axes of motion than general X-ray CT systems that are designed specifically for prone positions, so there is a risk of interference between the scanner unit and other components (such as the bed, ceiling, or floor). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-130378 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 be able to execute highly safe control. 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] An X-ray CT apparatus according to an embodiment includes a scanner unit, a support unit, a selection unit, and a control unit. The scanner unit has an imaging system. The support unit has a movement mechanism for the scanner unit and supports the scanner unit. The selection unit selects a unit for moving the scanner unit according to an imaging mode based on the state of a subject. The control unit controls the unit according to drive conditions for each of the imaging modes. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus according to this embodiment. [Figure 2] FIG. 2 is a conceptual diagram showing the state of the scanner unit in the standing position photographing mode according to this embodiment. [Figure 3] FIG. 3 is a conceptual diagram showing the state of the scanner unit in the sitting position imaging mode according to this embodiment. [Figure 4] FIG. 4 is a conceptual diagram showing the state of the scanner unit in the supine position imaging mode according to this embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of the operation of the X-ray CT apparatus according to this embodiment. [Figure 6] FIG. 6 is a table showing the relationship between the shooting modes and the units to be controlled. [Figure 7] FIG. 7 is a diagram showing an example of a restricted movement range for tilting the scanner unit in the standing position imaging mode and the sitting position imaging mode. [Figure 8] FIG. 8 is a diagram showing an example of a restricted movement range for the up-and-down movement of the scanner unit in the standing position photographing mode. [Figure 9] FIG. 9 is a diagram showing an example of a restricted movement range for raising and lowering the scanner unit in the sitting position imaging mode. [Figure 10] FIG. 10 is a diagram showing an example of a limited movement range for tilting the scanner unit in the supine position imaging mode. [Figure 11]FIG. 11 is a diagram showing a first example of a method for switching between shooting modes. [Figure 12] FIG. 12 is a diagram showing a second example of a method for switching between shooting modes. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of an X-ray CT apparatus (X-ray computed tomography apparatus), a control method, and a control program will be described in detail with reference to the drawings. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate. Hereinafter, one embodiment will be described with reference to the drawings.

[0009] FIG. 1 is a diagram showing an example of the configuration of an X-ray CT apparatus 1 according to this embodiment. As shown in FIG. 1, the X-ray CT apparatus 1 includes a scanner unit 10, a bed 30, and a console 40. Although FIG. 1 illustrates multiple scanner units 10 for ease of explanation, the apparatus may actually include one or multiple scanner units. The scanner unit 10 is a scanning device configured to perform X-ray CT imaging of a subject P. The bed 30 is a transport device on which the subject P to be subjected to X-ray CT imaging is placed and which positions the subject P. The console 40 is a computer that controls the scanner unit 10. For example, the scanner unit 10 and the bed 30 are installed in a CT examination room, and the console 40 is installed in a control room adjacent to the CT examination room. The scanner unit 10, the bed 30, and the console 40 are connected to each other by wire or wirelessly so that they can communicate with each other. The console 40 does not necessarily have to be installed in the control room. For example, the console 40 may be installed in the same room as the scanner unit 10 and the bed 30. The console 40 may also be incorporated into the scanner unit 10 .

[0010] As shown in FIG. 1, the scanner unit 10 includes an X-ray tube 11, an X-ray detector 12, a rotating frame 13, an X-ray high voltage device 14, a control device 15, a wedge 16, a collimator 17, and a data acquisition system (DAS) 18.

[0011] The X-ray tube 11 irradiates the subject P with X-rays. Specifically, the X-ray tube 11 includes a cathode that generates thermoelectrons, an anode that generates X-rays upon receiving thermoelectrons flying from the cathode, and a vacuum tube that holds the cathode and anode. The X-ray tube 11 is connected to the X-ray high voltage device 14 via a high-voltage cable. A tube voltage is applied between the cathode and the anode by the X-ray high voltage device 14. The application of the tube voltage causes thermoelectrons to fly from the cathode toward the anode. A tube current flows as the thermoelectrons fly from the cathode toward the anode. X-rays are generated when the thermoelectrons collide with the anode.

[0012] The X-ray detector 12 detects X-rays emitted from the X-ray tube 11 and passing through the subject P, and outputs an electrical signal corresponding to the detected X-ray dose to the DAS 18. The X-ray detector 12 has a structure in which multiple X-ray detection element rows, each having multiple X-ray detection elements arranged in the channel direction, are arranged in the slice direction (row direction). The X-ray detector 12 is, for example, an indirect conversion type detector having a grid, a scintillator array, and a photosensor array. The scintillator array has multiple scintillators. The scintillator outputs light with an amount of light corresponding to the amount of incident X-rays. The grid is arranged on the X-ray incidence surface side of the scintillator array and has an X-ray shielding plate that absorbs scattered X-rays. The grid is sometimes called a collimator (one-dimensional collimator or two-dimensional collimator). The photosensor array converts the light into an electrical signal corresponding to the amount of light from the scintillator. For example, a photodiode is used as the photosensor.

[0013] The X-ray detector 12 may be a photon-counting detector.

[0014] In the case of a photon-counting detector, the scintillator converts incident X-rays into photons, the number of which corresponds to the intensity of the incident X-rays. The photosensor array amplifies the light received from the scintillator, converts it into an electrical signal, and generates an output signal (energy signal) having a peak value corresponding to the energy of the incident X-rays.

[0015] Furthermore, the X-ray detector 12 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electrical signal.

[0016] The rotating frame 13 is an annular frame that supports the X-ray tube 11 and the X-ray detector 12 rotatably around a rotation axis (Z-axis). Specifically, the rotating frame 13 supports the X-ray tube 11 and the X-ray detector 12 so that they face each other. In addition to the X-ray tube 11 and the X-ray detector 12, the rotating frame 13 also supports the X-ray high-voltage generator 14 and the DAS 18. The rotating frame 13 is supported on a fixed frame (not shown) so that it can rotate around the rotation axis. The rotation mechanism includes, for example, a motor that generates a rotational driving force and a bearing that transmits the rotational driving force to the rotating frame 13 to rotate it. The motor is provided on the fixed frame, and the bearing is physically connected to the rotating frame 13 and the motor, so that the rotating frame 13 rotates in response to the rotational force of the motor. The rotation of the rotating frame 13 around the rotation axis causes the X-ray tube 11 and the X-ray detector 12 to rotate around the rotation axis. The rotating frame 13 is an example of a rotating unit.

[0017] The X-ray high voltage device 14 has a high voltage generator and an X-ray control device. The high voltage generator has electrical circuits such as a transformer and a rectifier, and generates a high voltage to be applied to the X-ray tube 11 and a filament current to be supplied to the X-ray tube 11. The X-ray control device controls the output voltage according to the X-rays emitted by the X-ray tube 11. The high voltage generator may be of a transformer type or an inverter type. The X-ray high voltage device 14 may be provided on the rotating frame 13 within the scanner unit 10, or on a fixed frame (not shown) within the scanner unit 10.

[0018] The wedge 16 adjusts the dose of X-rays irradiated onto the subject P. Specifically, the wedge 16 attenuates the X-rays so that the dose of X-rays irradiated from the X-ray tube 11 onto the subject P has a predetermined distribution. For example, the wedge 16 is made of a metal plate such as aluminum, such as a wedge filter or a bow-tie filter.

[0019] The collimator 17 limits the irradiation range of the X-rays that have passed through the wedge 16. The collimator 17 slidably supports multiple lead plates that shield the X-rays, and adjusts the shape of the slits formed by the multiple lead plates. The collimator 17 is sometimes called an X-ray aperture.

[0020] The DAS 18 reads out an electrical signal from the X-ray detector 12 corresponding to the X-ray dose detected by the X-ray detector 12. The DAS 18 amplifies the read-out electrical signal and integrates the electrical signal over a view period to collect detection data having a digital value corresponding to the X-ray dose over the view period. The detection data is also called projection data. The DAS 18 is realized, for example, by an application specific integrated circuit (ASIC) equipped with circuit elements capable of generating projection data. The projection data is transmitted to the console 40 via a non-contact data transmission device or the like.

[0021] In this embodiment, an integral type X-ray detector 12 and an X-ray CT device 1 equipped with an integral type X-ray detector 12 are described as examples, but the technology according to this embodiment can also be applied to a photon counting type X-ray detector.

[0022] The rotating frame 13 and the fixed frame are each provided with a non-contact or contact communication circuit, and these communication circuits enable communication between the unit supported on the rotating frame 13 and an external device of the fixed frame or the scanner unit 10. For example, if optical communication is used as the non-contact communication method, the detection data generated by the DAS 18 is transmitted by optical communication from a transmitter having a light-emitting diode (LED) provided on the rotating frame 13 to a receiver having a photodiode provided on the fixed frame of the scanner unit 10, and the data is then transferred from the fixed frame to the console 40 by the transmitter. Note that, other communication methods may also be used, such as non-contact data transmission methods such as capacitive coupling and radio wave methods, as well as contact data transmission methods using a slip ring and electrode brushes.

[0023] The control device 15 controls the X-ray high-voltage generator 14 and the DAS 18 to perform X-ray CT imaging in accordance with the imaging control function 442 of the processing circuit 44 of the console 40. The control device 15 includes a processing circuit having a central processing unit (CPU) or a micro processing unit (MPU), and a drive mechanism such as a motor and an actuator. The processing circuit includes, as hardware resources, a processor such as a CPU and memory such as a read-only memory (ROM) or a random access memory (RAM). The control device 15 executes various functions using a processor that executes programs loaded in the memory. Note that various functions are not limited to being implemented by a single processing circuit. A processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to implement each function. The control device 15 may also be implemented using an ASIC or a field programmable gate array (FPGA). Additionally, the control device 15 may be realized by other Complex Programmable Logic Devices (CPLDs) or Simple Programmable Logic Devices (SPLDs).

[0024] The control device 15 has a function of controlling the operation of the scanner unit 10 and the bed 30 in response to input signals from an input interface 43 (described later) attached to the console 40 or the scanner unit 10, or in response to control signals from the processing circuit 44. For example, the control device 15 receives input signals to control the rotation of the rotating frame 13, control the tilt of the scanner unit 10, and control the operation of the bed 30 and the tabletop 33. Note that the control of tilting the scanner unit 10 is realized by the control device 15 rotating the rotating frame 13 around an axis parallel to the X-axis direction based on inclination angle (tilt angle) information input via an input interface attached to the scanner unit 10. Note that the control device 15 may be provided in the scanner unit 10 or in the console 40.

[0025] The bed 30 includes a base 31, a support frame 32, a top plate 33, and a bed driving device 34. The base 31 is placed on the floor. The base 31 is a housing that supports the support frame 32 so that it can move vertically (in the Y-axis direction) relative to the floor. The support frame 32 is a frame provided on top of the base 31. The support frame 32 supports the top plate 33 so that it can slide along the rotation axis (Z-axis). The top plate 33 is a flexible plate on which the subject P is placed.

[0026] The bed driving device 34 is housed in the housing of the bed 30. The bed driving device 34 is a motor or actuator that generates power to move the support frame 32 on which the subject P is placed and the tabletop 33. The bed driving device 34 operates under the control of the processing circuitry 44, the console 40, etc.

[0027] The console 40 has a memory 41, a display 42, an input interface 43, and a processing circuit 44. Data communication between the memory 41, the display 42, the input interface 43, and the processing circuit 44 is performed via a bus (BUS). Note that although the console 40 will be described as being separate from the scanner unit 10, the scanner unit 10 may include the console 40 or some of the components of the console 40.

[0028] The memory 41 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. In addition to an HDD or SSD, the memory 41 may be a portable storage medium such as a compact disc (CD), a digital versatile disc (DVD), a Blu-ray (registered trademark) disc (BD), or a flash memory. The memory 41 may also be a drive device that reads and writes various information from and to semiconductor memory elements such as flash memory and RAM. The storage area of ​​the memory 41 may be located within the X-ray CT apparatus 1 or may be located in an external storage device connected via a network.

[0029] The display 42 displays various types of information. Any of a variety of displays can be used as the display 42, as appropriate. For example, a liquid crystal display (LCD), a cathode ray tube (CRT) display, an organic electroluminescence display (OLED), or a plasma display can be used as the display 42. The display 42 may be provided anywhere in the control room. The display 42 may also be provided in the scanner unit 10. The display 42 may be a desktop type, or may be configured as a tablet terminal or the like capable of wireless communication with the main body of the console 40. The display 42 may also be one or more projectors.

[0030] The input interface 43 accepts various input operations from the operator, converts the accepted input operations into electrical signals, and outputs the electrical signals to the processing circuit 44. Examples of the input interface 43 that can be used include a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display, as appropriate. In this embodiment, the input interface 43 is not limited to a device equipped with physical operating components such as a mouse, keyboard, trackball, switch, button, joystick, touchpad, and touch panel display. For example, an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the device and outputs the electrical signals to the processing circuit 44 is also included as an example of the input interface 43. The input interface 43 may also be provided in the scanner unit 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 40 main body.

[0031] The processing circuitry 44 controls the overall operation of the X-ray CT apparatus 1 in response to electrical signals of input operations output from the input interface 43. The processing circuitry 44 generates image data based on electrical signals output from the X-ray detector 12. For example, the processing circuitry 44 has, as hardware resources, a processor such as a CPU, MPU, or GPU, and memory such as a ROM or RAM. The processing circuitry 44 executes a system control function 441, an imaging control function 442, an acquisition function 443, a determination function 444, a selection function 445, a unit control function 446, an image generation function 447, and a display control function 448 using a processor that executes a program loaded in the memory.

[0032] Note that each function is not limited to being realized by a single processing circuit, but may be realized by combining multiple independent processors to form a processing circuit, and each processor may execute a program to realize each function.

[0033] In the system control function 441, the processing circuitry 44 controls each part of the X-ray CT apparatus 1 according to the deployed control program. Also, in the system control function 441, the processing circuitry 44 controls the driving of the bed 30 via the control device 15.

[0034] In the imaging control function 442, the processing circuitry 44 controls the X-ray high voltage generator 14, the control device 15, and the DAS 18 in accordance with imaging conditions to perform X-ray CT imaging. In an acquisition function 443, the processing circuitry 44 acquires the test order. In the determination function 444, the processing circuitry 44 determines the imaging mode based on the examination order. In the selection function 445, the processing circuitry 44 selects a unit for moving the scanner unit 10 in accordance with an imaging mode based on the state of the subject. In the unit control function 446, the processing circuit 44 controls the units in accordance with the drive conditions for each shooting mode.

[0035] In the image generation function 447, the processing circuitry 44 performs reconstruction processing on projection data related to the subject P to generate a CT image. The reconstruction processing may be performed using a filtered back projection method or an iterative reconstruction method. Alternatively, the reconstruction processing may be performed by incorporating denoising processing using machine learning into these methods. The processing circuitry 44 converts the CT image into a cross-sectional image of an arbitrary cross section or a rendering image of an arbitrary viewpoint. The conversion is performed based on an input operation received from an operator via the input interface 43. For example, the processing circuitry 44 performs three-dimensional image processing such as volume rendering, surface volume rendering, pixel value projection processing, MPR (Multi-Planer Reconstruction) processing, and CPR (Curved MPR) processing on the reconstructed image data to generate a rendering image of an arbitrary viewpoint.

[0036] In display control function 448, processing circuitry 44 displays the generated CT images and rendering images, for example, on display 42.

[0037] Although the console 40 has been described as a single console that executes multiple functions, multiple functions may be executed by separate consoles. The processing circuitry 44 is not limited to being included in the console 40, but may also be included in an integrated server that collectively processes projection data acquired by multiple medical image diagnostic devices. Post-processing may be performed by either the console 40 or an external workstation. Furthermore, processing may be performed simultaneously by both the console 40 and the workstation.

[0038] There are various types of X-ray CT apparatus 1, such as third-generation CT and fourth-generation CT, and any of these types can be applied to this embodiment. Here, the third-generation CT is a rotate / rotate-type in which the X-ray tube and detector rotate together around the subject. The fourth-generation CT is a stationary / rotate-type in which a large number of X-ray detection elements arranged in a ring shape are fixed, and only the X-ray tube rotates around the subject.

[0039] Although not shown, the X-ray CT apparatus 1 may include a communication interface. The communication interface is an interface that connects the X-ray CT apparatus 1 to a workstation, a PACS (Picture Archiving and Communication System), an HIS (Hospital Information System), a RIS (Radiology Information System), etc. via a LAN (Local Area Network) or the like. The communication interface transmits and receives various types of information to and from the connected workstation, PACS, HIS, and RIS.

[0040] Next, the state of the scanner unit for each imaging mode according to this embodiment will be described with reference to the conceptual diagrams of FIGS. FIG. 2 is a conceptual diagram showing the state of the scanner unit 10 in an imaging mode (hereinafter also referred to as an upright imaging mode) for imaging a subject P in a standing position. In this embodiment, an X-ray CT apparatus compatible with both recumbent and upright positions is assumed. That is, in the upright imaging mode, the scanner unit 10 is fixed in a position where the opening OP faces vertically and is connected to a support unit 20 that stands upright in the vertical direction. The support unit 20 has a movement mechanism. The movement mechanism includes a tilt mechanism and an elevation mechanism. The scanner unit 10 and the support unit 20 are connected via the tilt mechanism and the elevation mechanism. The tilt mechanism rotates the scanner unit 10. For example, a general rotation mechanism using a gear, a conveyor, or the like may be used. The elevation mechanism moves the scanner unit 10 up and down in the vertical direction. For example, a general linear motion mechanism such as a rack and pinion mechanism may be used. The subject P is positioned in an upright position within the opening OP, and the subject P is imaged by moving the scanner unit 10 up and down using the elevation mechanism.

[0041] 3 is a conceptual diagram showing the state of the scanner unit 10 in an imaging mode for imaging a subject P in a seated position (hereinafter also referred to as a seated position imaging mode). In this embodiment, the seated position imaging mode includes both a case where the subject is seated in a chair and a case where the subject is seated in a wheelchair. As in the standing position imaging mode, the opening OP of the scanner unit 10 faces vertically. The subject P is positioned in the opening OP while seated in a wheelchair or chair, and the scanner unit 10 is moved up and down by the lifting mechanism to image the subject P.

[0042] Next, FIG. 4 is a conceptual diagram showing the state of the scanner unit 10 in an imaging mode for imaging the subject P in a supine position (hereinafter also referred to as a supine position imaging mode). 4, the scanner unit 10 is rotated 90 degrees from the orientation in the upright position imaging mode, and the opening OP faces horizontally. The subject P is in a supine position on the tabletop 33, and the tabletop 33 is moved so as to enter the opening OP, thereby imaging the subject P. That is, in the upright position imaging mode and the supine position imaging mode, the body axis direction of the subject is approximately perpendicular to each other.

[0043] The scanner unit 10 may be movable in the horizontal direction. For example, the support unit 20 itself has a drive mechanism that drives the scanner unit 10 along the longitudinal direction of the bed 30, and the scanner unit 10 moves together with the support unit 20 in the horizontal direction. Furthermore, although an example in which there is one support unit 20 is shown, another support unit 20 may be arranged at a position opposite to the scanner unit 10, so that two support units 20 are arranged.

[0044] Next, an example of the operation of the X-ray CT apparatus according to this embodiment will be described with reference to the flowchart of FIG.

[0045] In step SA1, the processing circuitry 44 acquires an examination order from, for example, the HIS using the acquisition function 443. The examination order includes, for example, patient information (such as name, age, and sex), an area to be imaged, and imaging mode information. Note that the processing circuitry 44 may also acquire the examination order from the RIS using the acquisition function 443.

[0046] In step SA2, the processing circuitry 44 determines the imaging mode using the determination function 444. For example, the processing circuitry 44 determines the imaging mode, such as the standing position imaging mode, the sitting position imaging mode, or the supine position imaging mode, based on the imaging mode information included in the examination order using the determination function 444. Note that the user may set the imaging mode using the console 40 or the like. Information regarding the imaging mode may be input to the X-ray CT apparatus 1, and the processing circuitry 44 may determine the imaging mode based on the input information using the determination function 444.

[0047] In step SA3, the selection function 445 causes the processing circuitry 44 to select at least one of the scanner unit and the bed as a unit to be controlled in accordance with the imaging mode based on the state of the subject P. Specifically, the selection function 445 selects a unit to be controlled associated with each imaging mode, such as the standing position imaging mode, the sitting position imaging mode, or the lying position imaging mode, and a drive mechanism related to moving the scanner unit 10 or the bed 30.

[0048] In step SA4, the processing circuitry 44 controls the control target unit based on the drive conditions for each imaging mode using the unit control function 446. Specifically, the control target unit is driven within the movement direction and movement range of the control target unit limited according to the imaging mode, and the imaging control function 442 causes the processing circuitry 44 to perform imaging (scanning) of the subject P. The movement range is set based on the layout of the room, such as an examination room. For example, the movement range may be set to a range in which the moving control target unit will not interfere with other units, depending on the layout, such as the height of the ceiling, the placement of the ceiling-hanging monitor and injector installed around the X-ray CT device 1, and the distances of the scanner unit 10 and support unit 20 from the wall.

[0049] Next, an example of the relationship between the shooting mode and the unit to be controlled will be described with reference to FIG. 6 is a table 60 showing combinations of imaging modes and units to be controlled. Here, the sitting imaging modes are classified into chair and wheelchair cases. Table 60 shows three imaging modes (standing, sitting (chair, wheelchair), lying down) and seven units to be controlled (lifting mechanism, tilt mechanism, horizontal movement mechanism, bed, safety sensor, ceiling camera, mechanical stopper).

[0050] The horizontal movement mechanism is a mechanism that moves the support unit 20 of the scanner unit 10. The horizontal movement mechanism moves the support unit 20, for example, along the longitudinal direction of the bed 30. The safety sensor is, for example, a distance sensor or a pressure sensor, and is a sensor that determines whether or not the subject P is present at the opening OP of the scanner unit 10. The ceiling camera is an imaging device that determines whether or not the subject P is present at the opening OP of the scanner unit 10. The mechanical stopper is a physical fixing mechanism that limits the tilt of the scanner unit 10 or the horizontal movement of the support unit 20 within a predetermined movement range.

[0051] The selection function 445 allows the processing circuit 44 to refer to the table 60 and determine which mechanism to select as the unit to be controlled in which shooting mode. In Fig. 6, "◯" indicates a unit to be controlled, and "X" indicates a unit that is not to be controlled. The unit control function 446 allows the processing circuit 44 to turn off the power or disable a unit that is not to be controlled so that the function will not be activated or started.

[0052] Specifically, for example, if the shooting mode is "standing position shooting mode," the lifting mechanism, tilting mechanism, upper safety camera, ceiling camera, and mechanical stopper are selected as units to be controlled. Note that, although not shown here, information such as the driving range and installation location of each mechanism selected as a unit to be controlled may also be stored in table 60 in association with the shooting mode. That is, in the case of a lifting mechanism, information such as the height range in which it operates, in the case of a mechanical stopper, where the mechanical stopper is located to function, and in the case of a safety sensor, which safety sensor is to be used and which safety line is not to be used, i.e., turned off, may also be stored.

[0053] Next, an example of the restricted movement range regarding the tilt of the scanner unit 10 in the standing position imaging mode and the sitting position imaging mode will be described with reference to FIG. 7 shows the standing position imaging mode and the sitting position imaging mode, so the opening OP of the scanner unit 10 faces vertically. In FIG. 7, the limited movement range of the scanner unit 10 is represented as a tilt range 70. A tilt mechanism 71 for tilting the scanner unit 10 is also shown by a dashed line. The tilt range 70 defines the angle at which the scanner unit 10 can be tilted without coming into contact with the subject P when the subject P is positioned within the opening OP of the scanner unit 10.

[0054] Furthermore, as a controlled unit for defining tilt range 70, for example, mechanical stopper 72 is designed to protrude from support portion 22 and physically stop the rotation of scanner unit 10. The tilt range up to when scanner unit 10, rotated by tilt mechanism 71, collides with mechanical stopper 72 becomes tilt range 70.

[0055] Also included in the controlled units in the standing position imaging mode and the sitting position imaging mode is a safety sensor 73 for detecting the subject P or other indoor equipment from tipping over. The safety sensor 73 is, for example, a laser distance measuring sensor that detects wobbling or tipping over when the round-trip time (distance) of the laser changes. For example, if wobbling or tipping over occurs, the tilt of the scanner unit 10 can be stopped. Alternatively, a pressure sensor can be embedded in the floor of the scanner unit 10, and the processing circuit 44 can determine using the determination function 444 that a load equal to or greater than a threshold is applied, and stop the tilt of the scanner unit.

[0056] Next, an example of a limited range of movement regarding the elevation of the scanner unit 10 in the standing position photographing mode will be described with reference to FIG. 8, an elevator mechanism 81 raises and lowers the scanner unit 10, and the limited range of movement of the scanner unit 10 regarding the elevation (up and down movement) is represented as an elevator range 80. Here, since a standing position imaging mode is assumed, when the subject P is standing without collapsing, the elevator range 80 may be the maximum driving range of the elevator mechanism 81.

[0057] Next, an example of a limited range of movement regarding the elevation of the scanner unit 10 in the sitting position imaging mode will be described with reference to FIG. Compared to the standing position imaging mode of FIG. 8 , in the sitting position imaging mode of FIG. 9 , the subject P is seated or in a wheelchair. If the scanner unit 10 were allowed to descend to its maximum driving range, there is a possibility that the subject P's knees would be pinched when the scanner unit 10 descends. Therefore, to prevent the scanner unit 10 from descending below a certain height, a lifting range 90 of the scanner unit 10 is set, for example, by a mechanical stopper 91 installed in the lifting direction of the scanner unit 10. As in the standing position imaging mode, the processing circuit 44 selects the safety sensor 73 as the unit to be controlled using the selection function 445, and the processing circuit 44 detects the subject P's swaying or falling over using the unit control function 446, and stops the driving of the scanner unit 10. Furthermore, the safety sensor may be installed on the bottom side of the scanner unit 10 in the standing position imaging mode and the sitting position imaging mode, and the scanner unit 10 may stop when the distance between the subject P's thigh and the bottom side of the scanner unit 10 reaches a predetermined value.

[0058] Next, an example of a limited movement range for tilting the scanner unit in the supine position imaging mode will be described with reference to FIG. In the supine position imaging mode, the opening OP of the scanner unit 10 faces horizontally. At this time, the limited tilt movement range of the scanner unit 10 is represented as a tilt range 100. The tilt range 100 is defined as the angle at which the scanner unit 10 can be tilted without coming into contact with the subject P and the top board 33 of the bed 30 when the subject P is inserted into the opening of the scanner unit 10.

[0059] When the imaging mode of the X-ray CT apparatus 1 is set to the supine position imaging mode, for example, a mechanical stopper 101 is designed as a unit to be controlled to define the tilt range 100, protruding from the support part 22 to physically stop the tilt of the scanner part 10. The tilt range 100 is the range of tilt until the scanner part 10, rotated by the tilt mechanism 71, hits the mechanical stopper 101. In the supine position imaging mode, the lifting mechanism is disabled to prevent the scanner part 10 from moving up and down.

[0060] In the supine position imaging mode, the support unit 20 may be designed to be movable horizontally by a horizontal movement mechanism. In this case, the movement range of the support unit 20 may be limited to define a horizontal movement range 102. The horizontal movement range 102 may be set, for example, within a range in which the scanner unit 10 or the support unit 20 does not collide with the bed 30.

[0061] Next, a first example of a method for switching between shooting modes will be described with reference to FIG. FIG. 11 illustrates a transition from the supine position imaging mode to the upright position imaging mode. For example, if the imaging mode determined in step SA2 of FIG. 5 does not match the current state of the scanner unit 10 and the bed 30, the imaging mode is switched to the determined imaging mode. Even if the posture of the scanner unit 10 changes during this imaging mode switch, the processing circuit 44 selects a unit to be controlled and limits its movement range using the selection function 445. Specifically, the processing circuit 44 controls the drive related to the transition of the imaging mode using the unit control function 446 when the scanner unit 10 is within a specific range. Starting from the supine position imaging mode in FIG. 11(a), in FIG. 11(b), the top plate 33 of the bed 30, which is the unit to be controlled, moves to a position as far away from the scanner unit 10 as possible to avoid interference when the scanner unit 10 is tilted. In FIG. 11(c), the tilt mechanism tilts the scanner unit 10 so that the scanner unit 10 is in the upright photographing mode, and after the opening OP faces vertically, the lifting mechanism moves the scanner unit 10 vertically upward.

[0062] In addition, in the imaging mode switching operation, the processing circuitry 44 may detect whether the subject P and instruments are present around the scanner unit using the unit control function 446 based on information from the ceiling camera, safety sensors, etc., and may execute an interlock mechanism to prevent interference with the subject P and instruments. For example, the tilt mechanism and lift mechanism of the bed 30 and scanner unit 10 may be disabled until it is detected that the subject P and instruments are not present in the image captured by the ceiling camera.

[0063] 11 assumes that the scanner unit 10 is raised after tilting. However, the tilt mechanism and the lifting mechanism may be controlled to operate simultaneously and cooperatively. For example, when changing from the lying-down imaging mode to the upright imaging mode, the tilt mechanism may rotate the scanner unit 10 so that the opening faces vertically for the upright imaging mode, while the lifting mechanism may lift the scanner unit 10. In this case, the lifting mechanism may lift the scanner unit 10 at a slow first speed until the tilt mechanism completes the tilt to the upright imaging mode. After the tilt of the scanner unit 10 is complete, the lifting mechanism may lift the scanner unit 10 at a second speed faster than the first speed. This shortens the time required to switch imaging modes and improves workflow.

[0064] Next, a second example of a method for switching between shooting modes will be described with reference to FIG. Figure 12 shows a transition of the imaging mode from the upright imaging mode to the lying-down imaging mode. Similarly, starting from the upright imaging mode in Figure 12(a), in Figure 12(b), the scanner unit 10, which is the unit to be controlled, is lowered by the lifting mechanism from its maximum height in the upright imaging mode to a position where it will not interfere with the ceiling when tilted. Then, in Figure 12(c), the tilting mechanism tilts the scanner unit 10 so that it enters the lying-down imaging mode, i.e., so that the opening OP faces horizontally.

[0065] As an interlock mechanism, the tilt mechanism may be disabled when the scanner unit 10 has not been lowered from the maximum height to a predetermined height.

[0066] 11, in the method of switching the imaging mode shown in Fig. 12, the tilt mechanism and the lifting mechanism may be controlled to be driven together and controlled in cooperation with each other. Until the lifting mechanism has completed the descent of the scanner unit 10 to the supine position imaging mode, the tilt mechanism may tilt the scanner unit 10 to the supine position imaging mode at a slow first speed to avoid interference with the ceiling, and after the descent of the scanner unit 10 has completed, the tilt mechanism may tilt the scanner unit 10 at a second speed faster than the first speed.

[0067] In this embodiment, the upright position imaging mode, the sitting position imaging mode, and the supine position imaging mode are assumed, but similar processing can be performed even if a state in which the subject P is tilted is included as one type of imaging mode. Also, in this embodiment, an example of the X-ray CT apparatus 1 is shown, but in driving a bed in other medical image diagnostic apparatuses such as a magnetic resonance imaging apparatus, the control target unit can be set in a similar manner and the movement range can be limited.

[0068] Furthermore, virtual reality (VR) and augmented reality (AR) technologies may be used to set up a virtual interlock space and restrict the movement range of the controlled unit. For example, a contact area where the controlled unit may come into contact may be calculated based on images captured by cameras installed on the ceiling and walls of the room, and the movement range may be restricted if there is a risk of contact.

[0069] According to the present embodiment described above, a control target unit for moving the scanner unit is selected according to the imaging mode, such as standing position imaging mode, sitting position imaging mode, or lying position imaging mode, and the control target unit is driven according to the driving conditions for each imaging mode. This allows the units to be driven while avoiding interference when imaging in the imaging mode or when switching between imaging modes. Furthermore, because only the units necessary according to the imaging mode are set as control target units, highly safe control can be performed without erroneous detection or malfunction.

[0070] The term "processor" used in the above description refers to a circuit such as a CPU, a GPU, an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)). A processor realizes its functions by reading and executing a program stored in a memory circuit. Note that instead of storing a program in a memory circuit, the processor may be configured so that the program is directly embedded in the circuit. In this case, the processor realizes its functions by reading and executing the program embedded in the circuit. Furthermore, instead of executing a program, the function corresponding to the program may be realized by combining logic circuits. Note that each processor in this embodiment is not limited to being configured as a single circuit, but may be configured as a single processor by combining multiple independent circuits to realize its function. Furthermore, multiple components may be integrated into a single processor to realize its function.

[0071] 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]

[0072] 1 X-ray CT device 10 Scanner unit 11 X-ray tube 12 X-ray detector 13 Rotating Frame 14 X-ray high voltage device 15 Control device 16 Wedge 17 Collimator 18 Data Collection Circuit 20 Support part 22 Support part 30 berths 31 Foundation 32 Support frame 33 Top plate 34 Bed drive unit 40 Console 41 memory 42 Display 43 Input Interface 44 Processing circuit 60 tables 70,100 tilt range 71 Tilt mechanism 72,91,101 Mechanical Stopper 73 Safety Sensor 80,90 Lifting range 81 Lifting mechanism 102 Horizontal movement range 441 System Control Functions 442 Shooting control function 443 Retrieval Function 444 Judgment Function 445 Selection Function 446 Unit Control Function 447 Image generation function 448 Display Control Function OP opening

Claims

1. a scanner unit having an imaging system; a support unit having a movement mechanism for the scanner unit and supporting the scanner unit; a selection unit that selects a unit for moving the scanner unit in accordance with an imaging mode based on a state of a subject; a control unit that controls the unit in accordance with a driving condition for each of the photographing modes; An X-ray CT device comprising:

2. the unit includes the movement mechanism, the movement mechanism includes a lifting mechanism that lifts and lowers the scanner unit and a tilting mechanism that tilts the scanner unit, 2. The X-ray CT apparatus according to claim 1, wherein the control unit controls the lifting mechanism and the tilting mechanism so as to limit the movement direction and movement range thereof in accordance with a driving condition for each of the imaging modes.

3. The X-ray CT apparatus according to claim 2 , wherein the movement range is determined based on a layout of a room in which the scanner unit is placed.

4. the unit includes an interlock mechanism and a safety sensor; the selection unit selects whether or not to use the interlock mechanism and the safety sensor for each of the photographing modes, 2. The X-ray CT apparatus according to claim 1, wherein the control unit controls the interlock mechanism and the safety sensor selected to be used by the selection unit in accordance with a driving condition for each of the imaging modes.

5. the unit includes a bed on which the subject is placed, The X-ray CT apparatus according to claim 1 , wherein the control unit controls movement of the bed in accordance with a driving condition for each of the imaging modes.

6. the unit includes a horizontal movement mechanism that moves the support part along the longitudinal direction of the bed, 6. The X-ray CT apparatus according to claim 5, wherein the control unit restricts the movement range of the horizontal movement mechanism in a direction in which the support unit moves away from the bed when the imaging mode is a supine imaging mode in which an image of the subject in a supine position is captured.

7. The X-ray CT apparatus according to claim 2 , wherein the control unit controls driving related to the transition of the imaging mode when the scanner unit is present within a specific range.

8. The X-ray CT apparatus according to claim 7 , wherein the control unit drives the lifting mechanism and the tilting mechanism simultaneously.

9. When the control unit shifts from a standing position imaging mode, which is an imaging mode for imaging the subject in an upright position, to a lying position imaging mode, which is an imaging mode for imaging the subject in a lying position, 3. The X-ray CT apparatus according to claim 2, wherein the tilt mechanism is controlled so as to tilt the scanner unit at a first speed while the scanner unit is descending, and to tilt the scanner unit at a second speed faster than the first speed after the scanner unit has completed descending.

10. When the control unit shifts from a supine position imaging mode, which is an imaging mode for imaging the subject in a supine position, to a standing position imaging mode, which is an imaging mode for imaging the subject in a standing position, 3. The X-ray CT apparatus according to claim 2, wherein the lifting mechanism is controlled so as to lift the scanner unit at a first speed while the scanner unit is tilted, and to lift the scanner unit at a second speed faster than the first speed after the tilt of the scanner unit is completed.

11. the state of the subject includes two different states; The X-ray CT apparatus according to claim 1 , wherein the body axis directions of the subject in the two different states are substantially perpendicular to each other.

12. 1. A control method for an X-ray CT apparatus including a scanner unit having an imaging system and a support unit having a movement mechanism for the scanner unit and supporting the scanner unit, comprising: selecting a unit for moving the scanner unit in accordance with an imaging mode based on the state of the subject; controlling the unit in accordance with the driving conditions for each of the photographing modes; Control method.

13. A control program for an X-ray CT apparatus including a scanner unit having an imaging system and a support unit having a movement mechanism for the scanner unit and supporting the scanner unit, the program comprising: On the computer, a selection function for selecting a unit for moving the scanner unit in accordance with an imaging mode based on the state of the subject; a control function for controlling the unit in accordance with the driving conditions for each of the photographing modes; Control program.

Images