JP6883963B2 - X-ray computed tomography equipment - Google Patents

Description

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

Traditionally, X-ray computed tomography is usually performed in a lying position with the patient lying on the bed. On the other hand, X-ray computed tomography of a standing subject is desired.

At this time, the computed tomography (CT) apparatus used conventionally is executed in a state of being tilted by 90 °. At this time, if the subject is out of the imaging range, the collected image cannot be used for diagnosis, and there is a problem that unnecessary exposure occurs.

For this reason, in order to confirm in advance that there is no interference between the subject, the chair-type sleeper, etc. and the gantry body when the gantry body is lowered from the ceiling side in the horizontally mounted X-ray CT device. In addition, there is a technique of providing an interference prevention device that irradiates an interference inspection light beam having a circumferential irradiation area having a predetermined radius smaller than the radius of an inspection hole (opening of a gantry) into which a subject is inserted downward.

At this time, when trying to prevent unnecessary exposure by setting a predetermined radius to the same radius as the shooting range using the above-mentioned interference prevention device, shooting is stopped even if a part other than the shooting area goes out of the shooting range. There is a problem that it becomes necessary to take measures such as, and the shooting time becomes long.

Japanese Unexamined Patent Publication No. 10-277023

An object of the embodiment is to provide an X-ray computed tomography apparatus capable of reducing unnecessary exposure to a subject without causing interference between the subject and the gantry.

The X-ray computed tomography apparatus according to the present embodiment includes a gantry, a storage circuit, and a control circuit. The gantry has an X-ray tube and an X-ray detector across the opening and moves relative to the floor of the laboratory to image the subject by the X-rays emitted from the X-ray tube. It is possible. Inside the opening, the storage circuit interferes with the information relating to the first boundary indicating the outer edge of the imaging field of view and the interference between the subject and the gantry between the first boundary and the inner surface of the opening. The information related to the second boundary for preventing the above is stored. The control circuit controls the X-ray tube so as to stop the irradiation of X-rays based on the relative positional relationship between the scan target area of the subject and the first boundary, or the non-existence of the subject. The gantry is controlled so as to stop the movement of the gantry based on the relative positional relationship between the scan target area and the second boundary.

FIG. 1 is a diagram showing a configuration of an X-ray computed tomography apparatus according to the first embodiment. FIG. 2 is a diagram showing an example of the detection range of the subject by the upper subject detector provided on the horizontal member of the first embodiment. FIG. 3 is a perspective view showing a gantry main body, a first boundary, and a second boundary according to the first embodiment. FIG. 4 is a diagram showing an example of a subject detection range by an open subject detector provided in the vicinity of the gantry main body according to the first embodiment. FIG. 5 is a detailed view for explaining FIG. 4 in more detail according to the first embodiment. FIG. 6A is a flowchart showing a processing procedure of the gantry control processing according to the first embodiment. FIG. 6B is a flowchart showing a processing procedure of the gantry control processing according to the first embodiment. FIG. 7 is a diagram showing a configuration of an X-ray computed tomography apparatus according to a second embodiment. FIG. 8 is a perspective view showing a scan range according to the second embodiment. FIG. 9A is a flowchart showing a processing procedure of a gantry control process for scanning scanno image collection according to the second embodiment. FIG. 9B is a flowchart showing a processing procedure of a gantry control process for collecting a scanno image according to the second embodiment. FIG. 10 is a flowchart showing a gantry control process in a scan performed after scanning scanning according to the second embodiment. FIG. 11 is a diagram relating to an explanation of a control mode relating to the movement of the gantry body according to a modified example of the first embodiment. FIG. 12 is a flowchart showing an example of a control mode setting procedure relating to the movement of the gantry body according to a modified example of the first embodiment. FIG. 13 is a diagram showing a configuration of an X-ray computed tomography apparatus according to a third embodiment.

(First Embodiment)
Hereinafter, the X-ray computed tomography apparatus according to the present embodiment will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an X-ray computed tomography apparatus 1 according to the present embodiment. As shown in FIG. 1, the X-ray computed tomography apparatus 1 according to the present embodiment includes a gantry device 10, a mounting table 43, and a console 50. For example, the gantry device 10 and the mounting table 43 are installed in a CT examination room. Further, the console 50 is installed in a control room adjacent to the CT examination room. The gantry device 10 and the console 50 are connected by wire or wirelessly so as to be able to communicate with each other. The gantry device 10 is a scanning device having a configuration for performing X-ray computed tomography of a subject in a standing or sitting state. The console 50 is a computer that controls the gantry device 10.

The gantry device 10 has a gantry main body 11 and a support column 13. Hereinafter, the vertical direction is defined as the Y direction. The direction perpendicular to the central axis R1 of the opening 15 and parallel to the horizontal axis R2 is defined as the X direction. The direction orthogonal to the Y direction and the X direction is defined as the Z direction.

As shown in FIG. 1, the gantry main body 11 is a substantially cylindrical structure in which an opening 15 having an imaging field of view (FOV) is formed. As shown in FIG. 1, the gantry main body 11 accommodates an X-ray tube 17 and an X-ray detector 19 arranged so as to face each other with the opening 15 interposed therebetween. The gantry body 11 performs X-ray computed tomography on a subject in a standing or sitting position. At this time, the X-ray computed tomography may be a helical scan or a conventional scan. Hereinafter, X-ray computed tomography is simply referred to as scanning. The gantry main body 11 is movable relative to the floor surface of the examination room in order to photograph the subject by the X-rays emitted from the X-ray tube 17. Hereinafter, the movement of the gantry main body 11 will be described, but the mounting pedestal 43 may be moved.

More specifically, the gantry main body 11 includes a main frame (not shown) formed of a metal such as aluminum, and a rotating frame 21 rotatably supported by the main frame around the central axis R1 via bearings or the like. Further has. An annular electrode (not shown) is provided at a contact portion of the main frame with the rotating frame 21. A conductive slider (not shown) is attached to the contact portion of the main frame so as to make sliding contact with the annular electrode.

The rotating frame 21 is a metal frame formed in a ring shape by a metal such as aluminum, and for example, an X-ray tube 17 and an X-ray detector 19 are attached. The X-ray tube 17 and the X-ray detector 19 may be fitted into a recess formed in the rotating frame 21, or may be fastened with a fastener such as a screw.

The rotating frame 21 receives power from the rotation driving device 23 and rotates around the central axis R1 at a constant angular velocity. The rotation drive device 23 generates power for rotating the rotation frame 21 according to the control from the gantry control circuit 25. The rotation drive device 23 generates power by driving at a rotation speed corresponding to the duty ratio and the like of the drive signal from the gantry control circuit 25. The rotation drive device 23 is realized by, for example, a motor such as a direct drive motor or a servo motor. The rotation drive device 23 is housed in, for example, the gantry main body 11.

As shown in FIG. 1, the support column 13 is a base that supports the gantry main body 11 away from the floor surface. The support column 13 is installed on the floor surface. The support column 13 is a structure that slidably supports the gantry main body 11 in the longitudinal direction of the support column 13. The support column 13 has a columnar shape such as a columnar shape or a prismatic shape. The strut 13 is formed of any substance such as plastic or metal. The support column 13 is attached to the side surface portion of the gantry main body 11. The strut 13 has a structure capable of supporting the gantry main body 11 so that the central axis R1 of the opening 15 faces the vertical Y direction in order to scan the subject in the standing or sitting state. The support column 13 has a robust structure for supporting the gantry body 11.

The support column 13 is not limited to the above structure. For example, although the support column 13 has a columnar shape, the present embodiment is not limited to this. For example, the support column 13 may have any shape such as a U shape as long as it can support at least one side portion of the gantry body. The support column 13 does not need to fix the gantry body 11 so that the central axis R1 faces the vertical Y direction. That is, the support column 13 may be configured to support the gantry main body 11 so as to be rotatable around the horizontal axis R2. Specifically, the support column 13 and the gantry main body 11 are connected to each other via bearings or the like so that the gantry main body 11 can rotate around the horizontal axis R2.

Further, the support column 13 is not limited to being able to support the gantry body 11 so that the central axis R1 maintains the Y direction or the central axis R1 maintains the Z direction, and the central axis R1 is around the horizontal axis R2. It may be stationary so as to face any angle.

As shown in FIG. 1, a gantry driving device 31 for sliding the gantry main body 11 in the Y direction is connected to the support column 13. The gantry drive device 31 generates power for sliding the gantry main body 11 in the longitudinal direction D according to the control from the gantry control circuit 25. Specifically, the gantry drive device 31 generates power by driving at a rotation speed corresponding to the duty ratio of the drive signal from the gantry control circuit 25 and the like.

The support column 13 receives power from the frame drive device 31 and slides the frame body 11 with respect to the support column 13 along the longitudinal direction D. The support column 13 receives power from the gantry drive device 31 and lowers the gantry main body 11 from the ceiling side of the CT examination room toward the gantry 43 before starting scanning of the subject. In the support column 13, the gantry driving device 31 raises the gantry main body 11 from the scanning position toward the ceiling of the CT examination room after the scanning of the subject is completed.

A drive device for tilting the gantry main body 11 (hereinafter, referred to as a tilt drive device) may be connected to the support column 13. The tilt drive device generates power for rotating the gantry main body 11 around the horizontal axis R2 according to the drive signal from the gantry control circuit 25. Specifically, the tilt drive device generates power by driving at a rotation speed corresponding to the duty ratio and the like of the drive signal from the gantry control circuit 25. The support column 13 receives power from the tilt drive device and rotates the gantry main body 11 around the horizontal axis R2. The gantry drive device 31 and the tilt drive device are realized by, for example, a motor such as a servo motor.

As shown in FIG. 1, a horizontal member (beam) 14 for hanging the two columns 13 is provided at the upper ends of the two columns 13 that slidably support the gantry body 11 along the vertical Y direction. That is, the horizontal member 14 hangs the two columns 13. The horizontal member 14 mounts the upper subject detector 16 at a position directly above the opening 15, for example.

The upper subject detector 16 is preferably provided at a position on the central axis R1 of the horizontal member 14. That is, the upper subject detector 16 is provided on the upper side of the opening 15. The upper subject detector 16 is a device capable of detecting a subject from directly above the subject along the vertical Y direction. The upper subject detector 16 may detect the ends of the subject (top of head, shoulders, ends of limbs, elbows, knees), or may detect the contour of the entire body of the subject. The upper subject detector 16 is, for example, a camera (movie camera (movie camera), video camera (video camera), etc.).

The upper subject detector 16 includes various distance sensors (optical (infrared, visible light) sensor, magnetic field (magnetic) sensor, sound wave sensor, ultrasonic sensor, etc.) for determining the distance between itself and the subject. ) May have. The upper subject detector 16 may be composed of various circuits and an optical system related to motion capture (motion sensor) for detecting the position of the subject.

The upper subject detector 16 outputs to the console 50 whether or not the subject is detected, the relative positional relationship of the subject with respect to the opening 15, the upper image of the subject, and the like. At this time, the relative positional relationship between the position of the subject in the upper image and the gantry main body 11 is specified. The upper subject detector 16 may output the presence / absence of detection of the subject, the relative positional relationship, the upper image, and the like to the gantry control circuit 25.

As shown in FIG. 1, the upper subject detector 16 has a detection range A1 capable of detecting the position of the subject. The upper subject detector 16 may have a detection range A1 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject. The reference position or the reference scale is, for example, an object that becomes immobile when the gantry main body 11 is moved, and is provided on, for example, a mounting table 43 or the like. The upper subject detector 16 may measure the distance to the subject by detecting the reference scale.

Further, when the horizontal member 14 is not provided in the gantry device 10, the upper subject detector 16 may be provided directly above the opening 15 and on the ceiling of the CT examination room. At this time, the upper subject detector 16 is preferably provided at a position on the central axis R1 on the ceiling of the CT examination room. A plurality of upper subject detectors 16 may be provided on the horizontal member 14 or the ceiling of the CT examination room.

FIG. 2 is a diagram showing an example of the detection range of the subject S by the upper subject detector 16. The alternate long and short dash line 151 in FIG. 2 indicates the boundary (hereinafter, referred to as the first boundary) between the imaging range and the non-imaging range of the subject S in the region (opening region) of the opening 15 of the gantry main body 11. .. The inside of the alternate long and short dash line 151 corresponds to the FOV (first region). That is, the inside of the alternate long and short dash line 151 corresponds to the range that can be reconstructed by the image reconstructing device 51 described later.

The broken line 153 in FIG. 2 indicates a boundary (second boundary: hereinafter referred to as an interference line) between the first boundary 151 and the outer edge of the opening region 15 to prevent interference between the subject S and the gantry main body 11. ing. The outside of the interference line 153 indicates an area that may interfere with the gantry body 11. The inside of the interference line 153 indicates a region that does not interfere with the gantry main body 11 (hereinafter, referred to as a non-interference region (second region)).

The region between the first boundary 151 and the second boundary 153 is a region where the projection data necessary for the reconstruction may not be aligned in the scan (CT scan) for the subject S, for example, in the reconstruction of the volume data. Or correspond to the non-reconstructed area. The volume data corresponding to the region between the first boundary 151 and the second boundary 153 is referred to as, for example, a mask region or the like.

FIG. 3 is a perspective view showing the gantry main body 11, the first boundary 151, and the second boundary 153. Range 155 in FIG. 3 indicates the diameter of the first boundary 151. The diameter 155 of the first boundary 151 is approximately equal to the diameter of the FOV. Range 157 in FIG. 3 indicates the diameter of the second boundary 153. The diameter 157 of the second boundary 153 is smaller than the diameter of the opening 15. The width Rw in FIG. 3, which is larger than the diameter 155 of the first boundary 151, corresponds to the width of the X-ray detector 19, that is, the number of columns.

As shown in FIG. 1, the X-ray tube 17 generates X-rays by receiving a high voltage applied from the high voltage generator 39. The high voltage generator 39 is attached to, for example, the rotating frame 21. The high voltage generator 39 generates a high voltage to be applied to the X-ray tube 17 under the control of the gantry control circuit 25 from the electric power supplied from the power supply device (not shown) of the gantry main body 11 via the annular electrode. The high voltage generator 39 and the X-ray tube 17 are connected via a high voltage cable (not shown). The high voltage generated by the high voltage generator 39 is applied to the X-ray tube 17 via the high voltage cable.

The X-ray detector 19 detects X-rays generated from the X-ray tube 17 and transmitted through the subject S. The X-ray detector 19 is equipped with a plurality of X-ray detection elements (not shown) arranged on a two-dimensional curved surface. Each X-ray detection element detects X-rays from the X-ray tube 17. Each X-ray detection element converts an electric signal having a peak value according to the intensity of the detected X-ray. Each X-ray detector has, for example, a scintillator and a photoelectric converter. The scintillator receives X-rays and emits fluorescence. The photoelectric converter converts the generated fluorescence into charge pulses. The charge pulse has a peak value according to the intensity of X-rays.

Specifically, as the photoelectric converter, a device such as a photomultiplier tube or a photodiode (Photo Diode) that converts a photon into an electric signal is used. The X-ray detector 19 according to the present embodiment is not limited to an indirect detection type detector that temporarily converts X-rays into fluorescence and then converts them into an electric signal, and directly converts X-rays into an electric signal. It may be a direct detection type detector.

The data acquisition circuit (Data Aquisition System: DAS) 41 collects digital data indicating the intensity of X-rays attenuated by the subject S for each view. The data acquisition circuit 41 is realized, for example, by a semiconductor integrated circuit in which an integrator circuit provided for each of a plurality of X-ray detection elements and an A / D converter are mounted in parallel. The data acquisition circuit 41 is connected to the X-ray detector 19 in the gantry main body 11.

The integrator circuit integrates the electrical signal from the X-ray detector over a predetermined view period to generate an integrator signal. The A / D converter A / D-converts the generated integrated signal to generate digital data having a data value corresponding to the peak value of the integrated signal. The converted digital data is called raw data. Raw data is a set of digital values of X-ray intensity identified by the channel number, column number, and view number indicating the collected view of the source X-ray detector. The raw data is supplied to the console 50 via, for example, a non-contact data transmission device (not shown) housed in the gantry body 11.

The gantry main body 11 includes not only the above-mentioned X-ray tube 17, X-ray detector 19, rotating frame 21, main frame, power supply device, high voltage generator 39, and data acquisition circuit 41, but also necessary for scanning. Various other devices may be accommodated. For example, a cooling device for cooling the X-ray tube may be attached to the rotating frame 21. Further, a fan for air conditioning may be attached to the gantry main body 11.

In the exterior of the gantry main body 11, an opening subject detector 42 is provided on the outer edge of the opening 15. The opening subject detector 42 is a device capable of detecting a part of the subject S located in the opening 15. The open subject detector 42 may detect the ends of the subject S (top of head, shoulders, ends of limbs, elbows, knees), or may detect the contour of the entire body of the subject. The aperture subject detector 42 is, for example, a camera (movie camera (movie camera), video camera (video camera), etc.).

The aperture subject detector 42 uses various distance sensors (optical (infrared, visible light) sensor, magnetic field sensor, sound wave sensor, ultrasonic sensor, etc.) for determining the distance between itself and the subject S. You may have. The aperture subject detector 42 may be composed of various circuits and an optical system related to motion capture for detecting the position of the subject S.

The opening subject detector 42 outputs to the console 50 whether or not the subject S is detected in the opening 15, the relative positional relationship of the subject S with respect to the opening 15, the opening image obtained by photographing the subject S, and the like. To do. At this time, the relative positional relationship between the position of the subject S in the aperture image and the gantry main body 11 is specified. The aperture subject detector 42 may output the presence / absence of detection of the subject S, the relative positional relationship, the aperture image, and the like to the gantry control circuit 25.

As shown in FIG. 1, the opening subject detector 42 has a detection range A2 capable of detecting the position of the subject S in the opening 15. The aperture subject detector 42 may have a detection range A2 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject S. The reference position or the reference scale is, for example, an object that becomes immobile when the gantry main body 11 is moved, and is provided on, for example, a mounting table 43 or the like. The aperture subject detector 42 may measure the distance from the subject S by detecting the reference scale. A plurality of opening subject detectors 42 may be provided on the outer edge of the gantry main body 11 and on the outer edge of the opening 15.

FIG. 4 is a diagram showing an example of the detection range of the subject S by the aperture subject detector 42. The range B in FIG. 4 indicates a range (hereinafter, referred to as a non-scan target area) that is not subject to imaging (undetectable by the aperture subject detector 42) in scanning the subject S. In scanning the subject S, the non-scanned area is required not to exit the interference line (second boundary) 153. The range C in FIG. 4 indicates the range to be photographed (hereinafter referred to as the scan target area) in the scan for the subject S. The scan target area is required not to exit the area defined by the first boundary 151, that is, the FOV.

FIG. 5 is a detailed view for explaining FIG. 4 in more detail. As shown in FIG. 5, the non-scanning area is included in the non-interfering area defined by the interference line 153. Further, as shown in FIG. 5, the scan target area is included in the imaging field of view (FOV). At this time, the scan is executed.

The gantry control circuit 25 controls the high voltage generator 39, the rotation drive device 23, and the gantry drive device 31 according to the control from the system control circuit 57 of the console 50. For example, the gantry control circuit 25 controls the gantry main body 11, various devices mounted on the gantry device 10, and the like according to the determination result determined by the determination circuit 63 described later. The specific control of the gantry device 10 by the gantry control circuit 25 will be described in detail later.

As hardware resources, the gantry control circuit 25 includes various processing devices (processors) such as a CPU (Central Processing Unit) and MPU (Micro Processing Unit), and various types such as a ROM (Read Only Memory) and a RAM (Random Access Memory). It has a storage device (memory, etc.).

Further, the gantry control circuit 25 includes an integrated circuit for a specific application (Application Special Integrated Circuit: ASIC), a field programmable gate array (Field Programmable Logical Device: FPGA), and another composite programmable logic device (FPGA). CPLD), may be realized by a simple programmable logic device (SPLD).

The processing device realizes the above function by reading and executing the program stored in the storage device. Instead of storing the program in the storage device, the program may be directly incorporated in the circuit of the processing device. In this case, the processing device realizes the above function by reading and executing the program incorporated in the circuit.

The gantry control circuit 25 may be provided on the support column 13 or the gantry main body 11, or may be provided on the console 50. The gantry control circuit 25 controls various circuits and various units mounted on the gantry device 10 according to various commands and information inputs input via the input device 59 provided on the exterior of the gantry main body 11. May be good.

The mounting table 43 is provided on the floor surface of the CT examination room. The mounting table 43 is a structure that supports the subject S in a standing or sitting state. That is, the subject S in the standing or sitting state is placed on the mounting table 43. The mounting table 43 has a robust structure for supporting the subject S in a standing or sitting position. The mounting table 43 is formed of any substance such as plastic or metal.

The upper end portion of the mounting table 43 may be composed of an artifact-free substance, that is, a substance having a small X-ray attenuation coefficient. The mounting table 43 has a size corresponding to the diameter of the opening 15 directly below the opening 15. As a result, when the gantry main body 11 is lowered to the lowermost end of the movable range that can be slidably moved along the longitudinal direction D of the support column 13, scanning is performed up to the lowermost end portion of the subject S placed on the mounting base 43. Can be executed.

A lower subject detector 45 is provided on the outer edge of the mounting table 43. That is, the lower subject detector 45 is provided on the lower side of the opening 15. The lower subject detector 45 is a device capable of detecting a part of the subject S located in the opening 15. The lower subject detector 45 prevents the subject S from being pinched by the lowering of the gantry main body 11, and makes the blind spots of the detection range A1 of the upper subject detector 16 and the detection range A2 of the open subject detector 42. It is provided on the mounting table 43 in order to eliminate it.

The lower subject detector 45 may detect the ends of the subject S (top of head, shoulders, ends of limbs, elbows, knees), or may detect the contour of the entire body of the subject. For example, the lower subject detector 45 is, for example, a camera (movie camera (movie camera), video camera (video camera), etc.). When the mounting table 43 is not installed, the lower subject detector 45 is installed on the floor surface of the CT examination room, for example, in the vicinity immediately below the opening 15.

The lower subject detector 45 uses various distance sensors (optical (infrared, visible light) sensor, magnetic field sensor, sound wave sensor, ultrasonic sensor, etc.) for determining the distance between itself and the subject S. You may have. Further, the lower subject detector 45 may be configured by various circuits and an optical system related to motion capture for detecting the position of the subject S.

The lower subject detector 45 outputs to the console 50 whether or not the subject S is detected in the opening 15, the relative positional relationship of the subject S with respect to the opening 15, the lower image obtained by photographing the subject S, and the like. To do. At this time, the relative positional relationship between the position of the subject S in the lower image and the gantry main body 11 is specified. The lower subject detector 45 may output the presence / absence of detection of the subject S, the relative positional relationship, the lower image, and the like to the gantry control circuit 25.

As shown in FIG. 1, the lower subject detector 45 has a detection range A3 capable of detecting the position of the subject S in the opening 15. The lower subject detector 45 may have a detection range A3 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject S. The reference position or reference scale is, for example, an object that becomes immobile when the gantry main body 11 is moved, and is provided on, for example, the ceiling of a CT examination room, a horizontal member 14, or the like. The lower subject detector 45 may measure the distance to the subject S by detecting the reference scale. Further, a plurality of lower subject detectors 45 may be provided on the outer edge of the mounting table 43 or the like.

As shown in FIG. 1, the console 50 includes an image reconstruction device 51, an image processing device 53, a main memory circuit 55, a system control circuit 57, and an input device 59 connected via a bus. The display device 61 and the determination circuit 63 are provided. Data communication between the image reconstruction device 51, the image processing device 53, the main memory circuit 55, the system control circuit 57, the input device 59, the display device 61, and the determination circuit 63 is performed via a bus. Will be done.

The image reconstructing device 51 reconstructs a CT image relating to the subject S based on the raw data from the console 50. Specifically, the image reconstruction device 51 includes a preprocessing unit 511, a projection data storage unit 513, and a reconstruction calculation unit 515. The image reconstruction device 51 is controlled by, for example, the system control circuit 57.

The pre-processing unit 511 preprocesses the raw data from the console 50. The preprocessing includes various correction processes such as logarithmic transformation, X-ray intensity correction, and offset correction. The raw data after preprocessing is called projection data. The projection data storage unit 513 is a storage device such as an HDD, SSD, or integrated circuit storage device that stores the projection data generated by the preprocessing unit 511.

The reconstruction calculation unit 515 generates a CT image expressing the spatial distribution of CT values with respect to the subject S based on the projection data. Examples of the image reconstruction algorithm include analytical image reconstruction methods such as the FBP (fixed back projection) method and the CBP (convolution back projection) method, and the ML-EM (maximum likelihood exposure exposure extraction) method and OS-EM (maximum likelihood exposure extraction) method. An existing image reconstruction algorithm such as a statistical image reconstruction method such as the projection maximization method may be used.

The image reconstruction device 51 has a processing device (processor) such as a CPU, MPU, and GPU (Graphics Processing Unit) and a storage device (memory) such as ROM and RAM as hardware resources. Further, the image reconstruction device 51 may be realized by an ASIC, an FPGA, a CPLD, or a SPLD. The processing device realizes the functions of the preprocessing unit 511 and the reconstruction calculation unit 515 by reading and executing the program stored in the storage device.

Instead of storing the program in the storage device, the program may be directly incorporated in the circuit of the processing device. In this case, the processing device realizes the functions of the preprocessing unit 511 and the reconstruction calculation unit 515 by reading and executing the program incorporated in the circuit. Further, a dedicated hardware circuit that functions as the preprocessing unit 511 and a dedicated hardware circuit that functions as the reconstruction calculation unit 515 may be mounted on the image reconstruction device.

The image processing device 53 performs various image processing on the CT image reconstructed by the image reconstructing device 51. For example, when the CT image is volume data, the image processing device 53 performs volume rendering, surface volume rendering, image value projection processing, MPR (Multi-Planer Reconnection) processing, CPR (Curved MPR) processing, and MIP on the CT image. A display image is generated by performing three-dimensional image processing such as (Maximum Intelligence Projection) processing. The image processing device 53 outputs the generated display image to the display device 61.

The image processing device 53 is a three-dimensional subject image (subject) based on outputs from a plurality of subject detectors (upper subject detector 16, open subject detector 42, lower subject detector 45). Specimen coordinate data) may be generated. Further, the image processing device 53 may extract the end portion of the subject S by using the outputs (images) from the plurality of subject detectors, or may extract the contour of the whole body of the subject S. Good.

The image processing device 53 has a processing device (processor) such as a CPU, MPU, and GPU and a storage device (memory) such as a ROM or RAM as hardware resources. Further, the image processing device 53 may be realized by an ASIC, an FPGA, a CPLD, or a SPLD. The image processing device 53 and the image reconstruction device 51 may be integrated on a single substrate in the console 50.

The image reconstruction device 51, the image processing device 53, and the system control circuit 57 may be integrated on a single board in the console 50, or may be distributed and mounted on a plurality of boards.

The main storage circuit 55 is a storage device such as an HDD, an SSD, or an integrated circuit storage device that stores various information. Further, the main storage circuit 55 may be a drive device or the like that reads and writes various information to and from a portable storage medium such as a CD-ROM drive, a DVD drive, or a flash memory. The main storage circuit 55 stores the reconstructed image (volume data) reconstructed by the image reconstructing device 51 and the medical image processed by the image processing device 53.

Further, the main storage circuit 55 stores the upper image generated by the upper subject detector 16, the aperture image generated by the aperture subject detector 42, and the lower image generated by the lower subject detector 45. The main memory circuit 55 stores a scan plan transmitted from the Radiological Information System (RIS) via an interface and network (not shown).

The main memory circuit 55 sets the gantry device 10 based on the program related to the scan according to the present embodiment, the outputs from the plurality of subject detectors, and the preset first boundary 151 and the second boundary (interference line) 153. Stores the gantry control program to be controlled. The main storage circuit 55 stores programs and determination conditions related to various determinations executed by the determination circuit 63.

The main storage circuit 55 stores the coordinate system (hereinafter referred to as the gantry coordinate system) related to the gantry device 10. In the gantry coordinate system, the main memory circuit 55 includes coordinate data relating to the first boundary 151 (hereinafter referred to as first boundary data) and coordinate data relating to the second boundary (interference line) 153 (hereinafter referred to as second boundary data). ) Is memorized. The main storage circuit 55 may store a coordinate identification program that specifies (extracts) coordinate data (hereinafter referred to as subject coordinate data) of a part of the subject S in each of the upper image, the opening image, and the lower image. .. Here, the part of the subject S is a region that may be an end in the contour of the subject S such as the crown, shoulders, ends of limbs, elbows, and knees.

The main storage circuit 55 stores the positional relationship between the first boundary 151 and the second boundary 153 and the gantry device 10. For example, in the main memory circuit 55, the information relating to the first boundary indicating the outer edge of the imaging field of view inside the opening 15 and the subject S and the gantry main body 11 between the first boundary and the inner surface of the opening 15 The information related to the second boundary for preventing interference with the second boundary is stored. The first boundary 151 and the second boundary (interference line) 153 can be appropriately changed via the input device 59. The main storage circuit 55 stores the scan shooting position input by the operator's instruction via the input device 59 and the shooting range along the vertical Y direction. Further, the main storage circuit 55 stores a predetermined warning according to the determination result determined by the determination circuit 63. The predetermined warning may be, for example, the determination result itself, or a display mode for alerting the operator.

The system control circuit 57 has a processing device (processor) such as a CPU, MPU, and GPU and a storage device (memory) such as a ROM or RAM as hardware resources. The system control circuit 57 functions as the center of the X-ray computed tomography apparatus 1 according to the present embodiment. Specifically, the system control circuit 57 reads out various programs stored in the main storage circuit 55, expands them on the memory, and sets each part and each circuit of the X-ray computed tomography apparatus 1 according to the expanded control program. Control.

Further, the system control circuit 57 controls various devices and various circuits according to various commands and information inputs input via the input device 59. The system control circuit 57 may execute the function related to the determination circuit 63. The system control circuit 57 reads a warning according to the determination result from the main storage circuit 55. The system control circuit 57 outputs the read warning to the display device 61.

The input device 59 has an input interface circuit that receives various commands, information inputs, and the like from the operator. As the input device 59, a keyboard, a mouse, various switches, and the like can be used. The input device 59 outputs various commands and information inputs input by the operator to the system control circuit 57. The input device 59 may be provided on the console 50 or the gantry device 10. The input device provided in the gantry device 10 outputs various commands, information inputs, and the like input by the operator to the gantry control circuit 25. For example, the input device 59 inputs changes, resetting, and the like regarding the first boundary 151 and the second boundary (interference line) 153. Further, the input device 59 inputs instructions such as start of scanning and restart of scanning. The input device 59 may input settings and changes of a specified part of the subject S in each of the upper image, the aperture image, and the lower image.

The display device 61 has a display circuit that displays various information such as a two-dimensional CT image and a display image. As the display device 61, for example, a CRT display, a liquid crystal display, an organic EL display, an LED display, a plasma display, or any other display known in the art can be appropriately used. The display device 61 displays a predetermined warning corresponding to the determination result. Further, the display device 61 may display that there is a problem in scanning accuracy when the non-scanning target area exceeds the interference line at the time of scanning.

The determination circuit 63 determines whether or not the subject S is mounted on the mounting table 43 by using the upper image and the lower image before moving (descending) the gantry main body 11 to the scan photographing position. In the determination circuit 63, the subject S is placed on the mounting table 43, and while the gantry main body 11 is moving (descending) to the scan imaging position, the position of the subject S and the second boundary in each of the upper image and the lower image Based on the positional relationship with the (interference line) 153, it is determined whether or not the subject S is located in the second region, that is, the non-interference region. The aperture image may be further used in the above determination.

Specifically, the determination circuit 63 extracts (identifies) the subject coordinate data in each of the upper image, the aperture image, and the lower image. At this time, the extracted subject coordinate data is associated with the region of the subject S (scan target region, non-scan target region). More specifically, the scan target area corresponds to the subject coordinate data (hereinafter, referred to as scan target coordinate data) included in the image capture range in the aperture image when the gantry main body 11 reaches the scan image capture position.

Further, the non-scan target area corresponds to the subject coordinate data (hereinafter referred to as non-scan coordinate data) that is not included in the imaging range in the upper image and the lower image when the gantry main body 11 reaches the scan imaging position. .. As a result, the scan target area and the non-scan target area are separated in the subject S. The extracted subject coordinate data is data indicating coordinates with respect to the gantry coordinate system.

Next, the determination circuit 63 determines whether or not the scan target region is located in the first region (FOV) by comparing the scan target coordinate data with the first boundary data. Further, the determination circuit 63 compares the non-scan coordinate data for each of the upper image and the lower image with the second boundary data to determine whether or not the non-scan target region is located in the second region (non-interference region). Is determined. That is, the determination circuit 63 executes the determination using the coordinates (boundary position information) of the first boundary 151 and the second boundary 153 in the gantry coordinate system and the subject coordinate data (subject position information). Hereinafter, the determination by the determination circuit 63 will be described in more detail.

In the determination circuit 63, the scan target region is the first region (FOV) based on the positional relationship between the position of the subject S in the aperture image and the first boundary 151, triggered by the arrival of the gantry main body 11 at the scan imaging position. Determine if it is located inside. That is, the determination circuit 63 determines whether or not the scan target coordinate data is located in the FOV based on the scan target coordinate data and the first boundary data.

In the determination circuit 63, during scanning of the subject S with respect to the scan target area by the gantry main body 11, the scan target area is determined based on the positional relationship (coordinate relationship) between the position of the scan target area in the aperture image and the first boundary 151. Determine if it is located in the FOV. That is, the determination circuit 63 is based on the relative positional relationship (coordinate relationship) between the scan target coordinate data and the first boundary data during the arrival of the gantry main body 11 at the scan shooting position and the scan with respect to the scan target area. It is determined whether or not the scan target area is located in the FOV.

The determination circuit 63 is a non-scanning target based on the positional relationship (coordinate relationship) between the position of the non-scanning target area and the second boundary (interference line) 153 in each of the upper image and the lower image during scanning with respect to the scanning target area. Determine if the region is located within the non-interfering region. That is, the determination circuit 63 positions the non-scan target area within the non-interference region based on the relative positional relationship (coordinate relationship) between the non-scan coordinate data and the second boundary data during scanning with respect to the scan target area. Judge whether or not it is done.

The determination circuit 63 outputs the determination result to the gantry control circuit 25. The determination circuit 63 may output the determination result to the system control circuit 57. The determination circuit 63 has a processing device (processor) such as a CPU or MPU and a storage device (memory) such as a ROM or RAM as hardware resources. Further, the determination circuit 63 may be realized by an ASIC, an FPGA, a CPLD, or a SPLD. The determination circuit 63 may be incorporated in the system control circuit 57, the gantry control circuit 25, and the like.

(Mount control function)
The gantry control function is a function of controlling the gantry device 10 in order to control the movement and scanning of the gantry main body 11 related to scanning based on the determination result output from the determination circuit 63. The process related to the gantry control function is called the gantry control process. Hereinafter, the function of the gantry control circuit 25 related to the gantry control process will be described in detail.

The gantry control circuit 25 controls the gantry device 10 based on the determination result by the determination circuit 63. In the scan of the subject S by the gantry main body 11, the gantry control circuit 25 stops the scan and the movement of the gantry main body 11 based on the positional relationship between the position of the subject S and the first boundary 151. Control the device 10. That is, the gantry control circuit 25 controls the gantry device 10 in order to stop the scan and the movement of the gantry main body 11 based on the comparison determination result between the scan target coordinate data and the first boundary data in the scan for the scan target area. To do.

In other words, the gantry control circuit 25 controls the X-ray tube 17 so as to stop the irradiation of X-rays based on the relative positional relationship between the scan target area of the subject S and the first boundary. Further, the gantry control circuit 25 controls the gantry 11 so as to stop the movement of the gantry 11 based on the relative positional relationship between the non-scanned area of the subject S and the second boundary. For example, the gantry control circuit 25 controls the X-ray tube 17 so as to stop the X-ray irradiation by the X-ray tube 17 when a part of the scan target area exceeds the first boundary. Further, the gantry control circuit 25 controls the gantry 11 so as to stop the movement of the gantry 11 when a part of the non-scanned area exceeds the second boundary.

Specifically, when it is determined that the subject S mounted on the mounting table 43 is located in the non-interference region before the frame main body 11 is lowered to the scan photographing position, the frame control circuit 25 determines. In response to the input of the instruction to move the gantry main body 11 to the scan shooting position, the gantry driving device 31 is controlled in order to lower the gantry main body 11 to the scan shooting position. Under the control of the gantry control circuit 25 with respect to the gantry drive device 31, the gantry main body 11 starts descending toward the scan photographing position.

While the gantry main body 11 is moving (descending) to the scan shooting position, the non-scan target area is located in the non-interference area, that is, the non-interference coordinate data is defined by the second boundary data in the non-interference area. When it is determined that the gantry control circuit 25 is located inside, the gantry control circuit 25 controls the gantry drive device 31 and the like in order to continue the descent of the gantry main body 11. By the control of the gantry control circuit 25 with respect to the gantry drive device 31, the lowering of the gantry main body 11 is continued toward the scan photographing position.

During the movement (descending) of the gantry main body 11 to the scan imaging position, a part of the subject S is located outside the non-interference region, that is, the non-interference region where the non-scan coordinate data is defined by the second boundary data. When it is determined that the gantry control circuit 25 is located outside the gantry, the gantry control circuit 25 controls the gantry drive device 31 in order to stop the movement of the gantry main body 11. The descent of the gantry main body 11 is stopped by the control of the gantry control circuit 25 with respect to the gantry drive device 31.

It is determined that the non-scanning target area is located in the non-interfering region, that is, the non-scanning coordinate data is located inside the non-interfering region defined by the second boundary data even after the descent of the gantry main body 11 is stopped. If so, the gantry control circuit 25 controls the gantry drive device 31 in order to move the gantry main body 11 to the scan shooting position again, triggered by an instruction to resume movement via the input device 59. Under the control of the gantry control circuit 25 with respect to the gantry drive device 31, the gantry main body 11 resumes descending toward the scan photographing position.

When it is determined that the scan target area is located in the FOV after the gantry main body 11 reaches the scan shooting position, that is, the scan target coordinate data is located inside the FOV defined by the first boundary data. The gantry control circuit 25 controls the gantry device 10 in order to start scanning the scan target area in response to an operator's scan start instruction via the input device 59.

Specifically, the scan is started by the control of the gantry control circuit 25 for the high voltage generator 39, the rotation drive device 23, and the like. When the scan to be started is a conventional scan, the gantry main body 11 does not move. When the scan to be started is a helical scan, the gantry control circuit 25 further controls the gantry drive device 31 in order to move (or reciprocate) the gantry body 11 within a preset imaging range.

When it is determined that the scan target area is located in the FOV during the scan for the scan target area, the gantry control circuit 25 controls the gantry device 10 to continue the scan. During scanning, the non-scanned area is outside the detection range of the aperture subject detector 42, and may be at any position. That is, since the non-scan target area does not need to be located in the FOV during scanning, the scan continues regardless of the position of the non-scan target area.

When it is determined that a part of the scan target area is located outside the FOV during scanning for the scan target area, that is, the scan target coordinate data is located outside the FOV defined by the first boundary data. The gantry control circuit 25 controls the gantry device 10 so as to stop scanning. Specifically, the gantry control circuit 25 controls the high voltage generator 39 in order to stop the exposure of X-rays to the scan target area of the subject S. The scan is stopped by the control of the gantry control circuit 25 with respect to the high voltage generator 39. At this time, the gantry control circuit 25 may control the rotation drive device 23 in order to stop the rotation of the rotation frame 21.

When the scan being executed is a helical scan, the gantry control circuit 25 controls the gantry drive device 31 in order to stop the movement of the gantry main body 11. The movement of the gantry main body 11 during scanning is stopped by the control of the gantry control circuit 25 with respect to the gantry drive device 31.

When it is determined that the scan target area is located in the FOV after the scan is stopped, the gantry control circuit 25 restarts the scan with the instruction to restart the scan via the input device 59. It controls the high voltage generator 39, the rotation drive device 23, and the like. The scan is restarted in the scan target area by the control of the gantry control circuit 25 for the high voltage generator 39, the rotation drive device 23, and the like.

6A and 6B are flowcharts showing an example of the processing procedure of the gantry control processing.
The first boundary 151 and the second boundary 153 are set (step Sa1). At this time, the first boundary data and the second boundary data are output from the main storage circuit 55 to the determination circuit 63. The subject S is detected by the upper subject detector 16, the open subject detector 42, and the lower subject detector 45 (step Sa2). If the subject S is not detected by these subject detectors, the subsequent processing is not executed. After the process of step Sa2, the upper subject detector 16 generates an upper image. Further, an aperture image is generated by the aperture subject detector 42 (step Sa3). In addition, the lower subject detector 45 generates a lower image.

At this time, non-scan coordinate data is extracted from the upper image and the lower image. The extracted non-scan coordinate data is associated with the non-scan target area of the subject S. As a result, the non-scanned area is specified. In addition, the scan target coordinate data is extracted from the aperture image. The extracted scan target coordinate data is associated with the scan target region of the subject S. As a result, the scan target area is specified.

The unscanned coordinate data for the upper and lower images are compared with the second boundary data. As a result, if the subject S is included in the non-interference region, the gantry main body 11 is lowered toward the scan imaging position, triggered by the operator's gantry lowering instruction via the input device 59 (step). Sa4).

If there is a non-scanning target area outside the non-interfering region in the upper image (step Sa5), that is, if there is non-scanning coordinate data outside the closed curve defined by the boundary data of the second boundary 153, the gantry body 11 descends. Is stopped (step Sa6). At this time, a predetermined warning is displayed on the display device 61. The predetermined warning may be any warning as long as it can notify the operator that "the subject has come out of the interference line". When the non-scan coordinate data is included in the closed curve defined by the boundary data of the second boundary 153 and the operator inputs an instruction to restart the descent via the input device 59, the descent of the gantry main body 11 is restarted. (Step Sa7).

If there is no non-scanning target area outside the non-interfering region in the upper image (step Sa5), the gantry main body 11 is lowered to the scanning shooting position (step Sa8). If the scan target area is included in the FOV in the aperture image (step Sa9), that is, if the scan target coordinate data is included in the closed curve (FOV) defined by the boundary data of the first boundary 151. Scanning is started by the operator's scanning start instruction via the input device 59 (step Sa10).

If there is a scan target area outside the FOV in the aperture image (step Sa11), that is, if there is scan target coordinate data outside the closed curve defined by the boundary data of the first boundary 151, scanning (exposure) is stopped. (Step Sa12). At this time, if the scan is a helical scan, the movement of the gantry main body 11 is also stopped. In addition, a predetermined warning is displayed on the display device 61. The predetermined warning may be any warning as long as it can notify the operator that "the scan target area has come out of the FOV".

The scan target area is included in the FOV in the aperture image (step Sa13), that is, the scan target coordinate data is included in the closed curve (FOV) defined by the boundary data of the first boundary 151, and the scan target coordinate data is included via the input device 59. When the scan restart instruction is input by the operator (step Sa14), the scan is restarted. If the scan does not resume, the scan ends.

If there is no scan target area outside the FOV in the aperture image (step Sa11), that is, if the scan target coordinate data is included inside the closed curve (FOV) defined by the boundary data of the first boundary 151, the scan is performed. The scan is executed until the end instruction is given (step Sa15).

According to the configuration described above, the following effects are obtained.
According to the X-ray computed tomography apparatus 1 according to the present embodiment, there is a sensor (subject detector) for detecting the subject S, and boundary position information related to the gantry main body 11 of the X-ray computed tomography apparatus 1. Based on the subject position information and the subject position information, it is determined whether or not the scan target coordinate data is included in the FOV, and if the scan target area extends outside the FOV, the scan is stopped and the scan target area is the FOV. You can resume scanning by returning inside. In addition, a predetermined warning can be displayed when the gantry main body 11 is stopped and the scan is stopped.

Further, according to the X-ray computed tomography apparatus 1 according to the present embodiment, it is determined whether or not the non-scan target area is out of the interference line in order to avoid interference with the gantry main body 11, and the non-scan target area is set. When leaving the interference line, the vertical movement of the gantry main body 11 can be stopped, and when the non-scanned area returns within the interference line, the vertical movement of the gantry main body 11 can be restarted.

That is, according to the X-ray computed tomography apparatus 1 according to the present embodiment, the apparatus itself recognizes at what height the gantry main body 11 is located with respect to the subject S, and the region goes out of the FOV. By determining whether or not is the scan target area, the scan can be stopped or a predetermined warning can be displayed. As a result, according to the X-ray computed tomography apparatus 1 according to the present embodiment, the scan time is not long, and the safety of the subject S is ensured while suppressing the occurrence of unnecessary exposure to the subject S. At the same time, it is possible to observe the area to be scanned.

From the above, according to the present embodiment, it is possible to provide the X-ray computed tomography apparatus 1 capable of reducing unnecessary exposure to the subject S without interfering with the subject S and the gantry main body 11. ..

(Modification example)
An example of this modification is to select a control mode for controlling the movement of the gantry main body 11 and execute the gantry control function in response to a change in the imaging field of view.

The main storage circuit 55 stores a program related to the first control mode and a program related to the second control mode. In the first control mode, when a part of the scan target area exceeds the first boundary, the X-ray tube 17 is controlled so as to stop the X-ray irradiation by the X-ray tube 17, and one of the non-scan target areas. This is a control mode in which the gantry main body 11 is controlled so as to stop the movement of the gantry main body 11 when the unit exceeds the second boundary. The second control mode is a control mode in which the gantry main body 11 is controlled so as to stop the movement of the gantry main body 11 when the contour of the subject S exceeds the second boundary. The main storage circuit 55 may store a correspondence table of the size of the imaging field of view with respect to the tilt angle.

The input device 59 inputs an instruction to change the size of the imaging field of view. The change in the size of the imaging field of view is executed, for example, by setting the scan range for the scanno image on the screen at the time of scanning planning displayed on the display device 61. The input device 59 inputs the changed imaging field of view determination instruction. The input device 59 outputs the determined size of the imaging field of view to the determination circuit 63.

The input device 59 inputs an instruction to tilt the gantry main body 11 with respect to the floor surface of the examination room. The tilt instruction may be input by pressing a switch provided on the exterior of the gantry main body 11, or by setting the tilt of the scan range with respect to the scanno image on the screen at the time of scanning planning displayed on the display device 61. It may be entered. The input device 59 outputs the size of the imaging field of view according to the tilt angle instructed by the tilt to the determination circuit 63. The size of the imaging field of view according to the tilt angle may be determined by the system control circuit 57 using the correspondence table stored in the main storage circuit 55. For example, when the imaging field of view on the rotation axis of the rotating frame 21 and the plane parallel to the vertical direction is rectangular, the shape (size) of the imaging field of view by tilting the gantry body 11 rotates this rectangle according to the tilt angle. A straight line that passes through each of the two vertices closest to the axis of rotation and is parallel to the axis of rotation, and is a parallelogram obtained by cutting this rotated rectangle.

The determination circuit 63 compares the contour of the subject S in the upper image and the aperture image with the size of the imaging field of view. By this comparison, the determination circuit 63 determines whether or not the contour of the subject S is included in the imaging field of view. That is, the determination circuit 63 executes the determination using the position information of the first boundary 151 and the subject position information regarding the change of the imaging field of view after the change. The determination circuit 63 outputs the determination result to the gantry control circuit 25. The determination circuit 63 may output the determination result to the system control circuit 57.

FIG. 11 is a view of the positional relationship between the imaging field of view and the contour of the subject S as viewed from the Y direction. The LL shown in FIG. 11 shows the maximum imaging field of view. The maximum imaging field of view LL includes the contour of the subject S. L shown in FIG. 11 indicates an imaging field of view narrower than the maximum imaging field of view LL. The imaging field of view L includes the contour of the subject S as well as the maximum imaging field of view LL. In the imaging field of view LL and the imaging field of view L, the determination circuit 63 determines that the contour of the subject S is included in the imaging field of view. M shown in FIG. 11 shows an imaging field of view narrower than the imaging field of view L. The imaging field of view M does not include the contour of the subject S. In the imaging field of view M, the determination circuit 63 determines that the contour of the subject S is not included in the imaging field of view.

The gantry control circuit 25 reads out the second control mode from the main memory circuit 55 when the determined imaging field of view, that is, the imaging field of view changed by the setting by the operator is narrower than the contour of the subject S. Next, the gantry control circuit 25 executes the movement of the gantry main body 11 in the second control mode. Further, the gantry control circuit 25 reads out the first control mode from the main memory circuit 55 when the determined imaging field of view, that is, the imaging field of view changed by the setting by the operator is wider than the contour of the subject S. Next, the gantry control circuit 25 executes the movement of the gantry main body 11 in the first control mode. The movement of the gantry main body 11 in the first control mode or the second control mode may be controlled by the system control circuit 57.

(Mount control function)
The gantry control function according to this modification is a function of controlling the gantry device 10 in order to control the movement and scanning of the gantry main body 11 based on the determination result according to the change in the imaging field of view. FIG. 12 is a flowchart showing an example of a control mode setting procedure related to the movement of the gantry main body 11 according to the present modification.

A contour image (upper image, aperture image, etc.) of the subject S is acquired in advance by the subject detector (step Sd1). The contour information of the subject S is output to the determination circuit 63. An input for changing the imaging field of view or a tilt of the gantry main body 11 is input via the input device 59 (step Sd2). When the tilt of the gantry main body 11 is input, the imaging field of view is set according to the tilt angle (step Sd3). After setting the imaging field of view according to the tilt angle or after inputting the imaging field of view, it is determined whether or not the contour of the subject S is included in the imaging field of view using the contour image (step Sd4).

When the contour of the subject S is included in the imaging field of view (Yes in step Sd4), the system control circuit 57 uses the input of the inclusion determination from the determination circuit 63 as a trigger to store the program related to the first control mode in the main memory circuit. Read from 55. As a result, the control of the movement of the gantry main body 11 is set as the first control mode (step Sd5). When the contour of the subject S is not included in the imaging field of view (No in step Sd4), the system control circuit 57 uses the input of the non-inclusion determination from the determination circuit 63 as a trigger to store the program related to the second control mode in the main memory circuit. Read from 55. As a result, the control of the movement of the gantry main body 11 is set as the second control mode (step Sd6). The movement of the gantry main body 11 is started in the set control mode (step Sd7).

According to the configuration described above, the following effects are obtained.
According to the X-ray computed tomography apparatus 1 according to the present embodiment, the control mode related to the control of the movement of the gantry main body 11 can be selected and set according to the change of the imaging field of view. That is, according to the X-ray computed tomography apparatus 1, the size of the imaging field of view and the subject are changed according to the change of the imaging field of view according to the instruction of the operator or the change of the imaging field of view due to the tilt of the gantry main body 11. By comparing with the contour of S, it is possible to determine whether or not the contour of the subject S is included in the imaging field of view, and determine (switch) the control mode in the movement of the gantry main body 11. As a result, according to the X-ray computer tomographic device 1, the subject S and the gantry do not interfere with each other and are unnecessary for the subject S, depending on the inclusion relationship between the size of the imaging field of view and the contour of the subject S. It is possible to control the movement of the gantry main body 11 with reduced exposure.

(Second Embodiment)
The difference from the first embodiment is that the aperture subject detector 42 is not mounted, and the non-scan target area and the scan target area are specified based on the imaging range set by the scanno image, and the first scan target area is specified. The purpose is to carry out the determination in the embodiment.

FIG. 7 is a diagram showing a configuration of an X-ray computed tomography apparatus 2 according to the present embodiment. In the following description, components having substantially the same function and configuration are designated by the same reference numerals, and duplicate explanations will be given when necessary.

A first upper subject detector 161 and a second upper subject detector 163 are mounted on the horizontal member 141. Specifically, the first upper subject detector 161 and the second upper subject detector 163 are located on the horizontal member 141 at symmetrical positions (line-symmetrical positions) with the central axis R1 in between. Will be installed. When the horizontal member 141 is not provided on the gantry device 101, the first upper subject detector 161 and the second upper subject detector 163 are axisymmetric positions with the central axis R1 in between. It may be provided on the ceiling of the CT examination room. The number of subject detectors provided on the horizontal member 141 is not limited to two.

The first upper subject detector 161 outputs to the console 50 whether or not the subject is detected, the relative positional relationship of the subject with respect to the opening 15, the first upper image of the subject, and the like. At this time, the relative positional relationship between the position of the subject (non-scan coordinate data) in the first upper image and the gantry main body 11 (gantry coordinate system) is specified. The first upper subject detector 161 may output the presence / absence of detection of the subject, the relative positional relationship, the first upper image, and the like to the gantry control circuit 25 or the like.

The second upper subject detector 163 outputs to the console 50 whether or not the subject is detected, the relative positional relationship of the subject with respect to the opening 15, the second upper image of the subject, and the like. At this time, the relative positional relationship between the position of the subject (non-scan coordinate data) in the second upper image and the gantry main body 11 (gantry coordinate system) is specified. The second upper subject detector 163 may output the presence / absence of detection of the subject, the relative positional relationship, the second upper image, and the like to the gantry control circuit 25 or the like.

As shown in FIG. 7, the first upper subject detector 161 has a detection range B1 capable of detecting the position of the subject. The first upper subject detector 161 may have a detection range B1 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject.

As shown in FIG. 7, the second upper subject detector 163 has a detection range B2 capable of detecting the position of the subject. The second upper subject detector 163 may have a detection range B2 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject. The detection range B1 and the detection range B2 are defined by, for example, substantially the same angle.

On the outer edge of the mounting table 43, a first lower subject detector 451 and a second lower subject detector 453 are provided at symmetrical positions (line-symmetrical positions) with the central axis R1 in between. When the mounting table 43 is not provided on the gantry device 101, the first lower subject detector 451 and the second lower subject detector 453 are axisymmetric positions with the central axis R1 in between. It may be provided on the floor surface of the CT examination room. The number of subject detectors provided on the mounting table 43 is not limited to two.

The first lower subject detector 451 outputs to the console 50 whether or not the subject is detected, the relative positional relationship of the subject with respect to the opening 15, the first lower image of the subject, and the like. At this time, the relative positional relationship between the position of the subject S (non-scan coordinate data) in the first lower image and the gantry main body 11 is specified. The first lower subject detector 451 may output the presence / absence of detection of the subject, the relative positional relationship, the first lower image, and the like to the gantry control circuit 25.

The second upper subject detector 163 outputs to the console 50 whether or not the subject is detected, the relative positional relationship of the subject with respect to the opening 15, the second lower image of the subject, and the like. At this time, the relative positional relationship between the position of the subject (non-scan coordinate data) in the second lower image and the gantry main body 11 is specified. The second lower subject detector 453 may output the presence / absence of detection of the subject, the relative positional relationship, the second lower image, and the like to the gantry control circuit 25.

As shown in FIG. 7, the first lower subject detector 451 has a detection range B3 capable of detecting the position of the subject. The first lower subject detector 451 may have a detection range B3 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject.

As shown in FIG. 7, the second lower subject detector 453 has a detection range B4 capable of detecting the position of the subject. The second lower subject detector 453 may have a detection range B4 capable of photographing a reference position or a reference scale that serves as a reference for the distance between itself and the subject. The detection range B3 and the detection range B4 are defined by, for example, substantially the same angle.

The image processing device 53 generates a scanno image based on the data output from the data acquisition circuit 41 in the scanno photographing. The generated scanno image is output to the display device 61.

The display device 61 displays a scanno image. At this time, the display device 61 superimposes and displays two boundary lines for setting the boundary of the scan range on the scanno image.

The input device 59 inputs an instruction for scanning the subject. The input device 59 inputs the scan range to the displayed scano image according to the instruction of the operator. For example, the input device 59 determines the scan range by moving the two boundary lines according to an instruction from the operator. The scan range may be determined by providing a predetermined margin with respect to the scan target area.

FIG. 8 is a perspective view showing an example of the scan range. As shown in FIG. 8, the scan range SR has a margin M with respect to the width Sob of the scan target area. The margin M corresponds to the difference between the scan range SR and the width Sub of the scan target area.

The system control circuit 57 controls each part, each circuit, each device, and the like related to the X-ray computed tomography apparatus 2 in order to execute the scanno imaging triggered by the input of the scanno imaging instruction. The system control circuit 57 controls each part, each circuit, each device, and the like related to the X-ray computed tomography apparatus 2 in order to execute a scan on the scan range set in the scanno image.

The system control circuit 57 associates the set scan range with the gantry coordinate system by aligning the positions. As a result, the system control circuit 57 can grasp the relative position of the gantry main body 11 at the time of scanning with respect to the subject S. The system control circuit 57 determines the scan target area (scan target coordinate data) based on the scan range and the first upper image, the second upper image, the first lower image, and the second lower image collected at the time of scanning. Identify. The system control circuit 57 outputs information (scan target coordinate data) regarding the specified scan target area to the determination circuit 63.

The system control circuit 57 is acquired by a subject detector (first upper subject detector 161, second upper subject detector 163, first lower subject detector 451 and second lower subject detector 453). The subject coordinate data in which the position information (subject coordinate data) of the subject S and the position information of the scan range set using the scanno image do not match (mismatch) are referred to as non-scan coordinate data (non-scan target area). ). The system control circuit 57 outputs information (scan target coordinate data) regarding the specified scan target area to the determination circuit 63. The scan target area and the non-scan target area may be determined (specified) by the determination circuit 63 or the gantry control circuit 25.

In the determination circuit 63, the subject S is placed on the mounting table by using the first upper image, the second upper image, the first lower image, and the second lower image before the gantry main body 11 is moved (descended) to the scanno imaging position. It is determined whether or not it is placed on 43. In the determination circuit 63, the first upper image, the second upper image, the first lower image, and the first upper image, the first lower image, and the first upper image, the first lower image, and the first lower image, while the subject S is placed on the mounting table 43 and the gantry main body 11 is moving (lowering) to the scanno imaging position 2 It is determined whether or not the subject S is located in the second region (non-interference region) based on the positional relationship between the position of the subject S and the second boundary (interference line) 153 in each of the lower images. ..

Specifically, the determination circuit 63 extracts (identifies) the subject coordinate data in each of the first upper image, the second upper image, the first lower image, and the second lower image. The determination circuit 63 determines whether or not the non-scan coordinate data exists outside the second region (non-interference region) by comparing the subject coordinate data with the second boundary data. That is, the determination circuit 63 executes the determination using the coordinates (boundary position information) of the second boundary 153 in the gantry coordinate system and the subject coordinate data (subject position information).

The determination circuit 63 compares the subject coordinate data with the second boundary data during the arrival of the gantry main body 11 at the scanno imaging position and during the scanno imaging, so that the subject is outside the second region (non-interference region). Determine if the coordinate data exists.

The determination circuit 63 is a scan target based on the positional relationship between the position of the scan target area specified by the scanno image and the first boundary 151 during the arrival of the gantry main body 11 at the scan shooting position and the scan with respect to the scan target area. Determine if the region is located within the first region (FOV).

Further, it was set using the position information (subject coordinate data) of the subject S acquired by the subject detector and the scanno image during the arrival of the gantry main body 11 to the scan imaging position and the scanning of the scan target area. If the position information in the scan range does not match, that is, if the gantry body 11 has not reached the scan range, the determination circuit 63 determines whether the non-scan coordinate data is located within the second boundary (inside the non-interference region). Judge whether or not.

When it is determined that the subject S placed on the mounting table 43 is located in the non-interference region before the gantry main body 11 is lowered to the scanno imaging position, the gantry control circuit 25 mounts the gantry at the scanning position. In response to the input of the instruction to move the main body 11, the gantry drive device 31 is controlled in order to lower the gantry main body 11 to the scanno photographing position. Under the control of the gantry control circuit 25 with respect to the gantry drive device 31, the gantry main body 11 starts descending toward the scanno photographing position.

While the gantry main body 11 is moving (descending) to the scanno shooting position, the non-scanning target area is located in the non-interfering area, that is, the non-interfering coordinate data is inside the non-interfering area defined by the second boundary data. When it is determined that the position is located in, the gantry control circuit 25 controls the gantry drive device 31 and the like in order to continue the descent of the gantry main body 11. By the control of the gantry control circuit 25 with respect to the gantry drive device 31, the lowering of the gantry main body 11 is continued toward the scanno photographing position.

During the movement (descending) of the gantry main body 11 to the scanno imaging position, a part of the subject S is located outside the non-interference region, that is, the non-interference region where the non-scan coordinate data is defined by the second boundary data. When it is determined that the gantry control circuit 25 is located outside the gantry, the gantry control circuit 25 controls the gantry drive device 31 in order to stop the movement of the gantry main body 11. The descent of the gantry main body 11 is stopped by the control of the gantry control circuit 25 with respect to the gantry drive device 31.

It is determined that the non-scanning target area is located in the non-interfering region, that is, the non-scan coordinate data is located inside the non-interfering region defined by the second boundary data even after the descent of the gantry main body 11 is stopped. If so, the gantry control circuit 25 controls the gantry drive device 31 in order to move the gantry main body 11 to the scanno photographing position again in response to the input of the movement restart instruction via the input device 59. Under the control of the gantry control circuit 25 with respect to the gantry drive device 31, the gantry main body 11 resumes descending toward the scanno photographing position.

When it is determined that the subject S is located in the FOV after the gantry main body 11 reaches the scanno imaging position, that is, the subject coordinate data is determined to be located inside the FOV defined by the first boundary data. The gantry control circuit 25 controls the gantry device 101 in order to start scanning scanning in response to an operator's scanno start instruction via the input device 59. Specifically, the scanno imaging is started by the control of the gantry control circuit 25 for the high voltage generator 39, the rotation drive device 23, and the like.

After the scanno shooting, while the gantry main body 11 is moving to the scan shooting position, the non-scan target area is located in the non-interference area, that is, the non-interference area where the non-scan coordinate data is defined by the second boundary data. When it is determined that the gantry control circuit 25 is located inside the gantry control circuit 25, the gantry control circuit 25 controls the gantry drive device 31 and the like in order to continue the movement of the gantry main body 11. By the control of the gantry control circuit 25 with respect to the gantry drive device 31, the lowering of the gantry main body 11 is continued toward the scan photographing position.

While the gantry body 11 is moving to the scan imaging position, a part of the subject S is located outside the non-interference region, that is, the non-scan coordinate data is outside the non-interference region defined by the second boundary data. When the position is determined, the gantry control circuit 25 controls the gantry drive device 31 in order to stop the movement of the gantry main body 11. The movement of the gantry main body 11 is stopped by the control of the gantry control circuit 25 with respect to the gantry drive device 31.

After the movement of the gantry main body 11 to the scan shooting position is stopped, the non-scan target area is located in the non-interference area, that is, the non-interference coordinate data is defined by the second boundary data in the non-interference area. When it is determined that the gantry control circuit 25 is located inside, the gantry control circuit 25 controls the gantry drive device 31 in order to move the gantry main body 11 to the scan shooting position again, triggered by an instruction to restart the movement via the input device 59. .. Under the control of the gantry control circuit 25 with respect to the gantry drive device 31, the gantry main body 11 resumes movement toward the scan photographing position.

(Mount control function)
9A and 9B are flowcharts showing an example of a processing procedure of a gantry control process relating to the collection of scanno images.
The first boundary 151 and the second boundary 153 are set (step Sb1). The subject S is detected by the first upper subject detector 161, the second upper subject detector 163, the first lower subject detector 451 and the second lower subject detector 453 (step Sb2). ). If the subject S is not detected by these subject detectors, the subsequent processing is not executed.

After the process of step Sb2, the first upper subject detector 161 generates the first upper image, and the second upper subject detector 163 generates the second upper image. In addition, the first lower subject detector 451 generates the first lower image, and the second lower subject detector 453 generates the second lower image (step Sb3). The generation of the first upper image, the second upper image, the first lower image, and the second lower image is appropriately generated and updated in real time.

At this time, the subject coordinate data is extracted in the upper image and the lower image. The subject coordinate data relating to the first and second upper images (hereinafter referred to as upper images) and the first and second lower images (hereinafter referred to as lower images) are compared with the second boundary data. As a result, if the subject coordinate data is included in the non-interference region, the gantry main body 11 is lowered toward the scanno imaging position, triggered by the operator's gantry lowering instruction via the input device 59 ( Step Sb4).

If the subject coordinate data is outside the non-interference region in the upper image and the lower image (step Sb5), that is, if the subject coordinate data is outside the closed curve defined by the boundary data of the second boundary 153, the gantry main body 11 Is stopped (step Sb6). When the subject coordinate data is included in the closed curve defined by the boundary data of the second boundary 153 and the operator inputs an instruction to restart the descent via the input device 59, the descent of the gantry main body 11 is restarted. (Step Sb7).

If there is no subject coordinate data outside the non-interfering region in the upper and lower images (step Sb5), the gantry body 11 is lowered to the scanno imaging position (step Sb8). The scanno shooting is started by the operator's instruction to start the scanno shooting via the input device 59 (step Sb9).

If the subject coordinate data is outside the non-interference region (step Sb10), that is, if the subject coordinate data is outside the closed curve defined by the boundary data of the second boundary 153, the scanno imaging is stopped (step). Sb11). The subject coordinate data is included in the non-interference region, that is, the subject coordinate data is included in the closed curve defined by the boundary data of the second boundary 153, and the instruction to resume scanning scanning is instructed via the input device 59. If input by the operator, scanno photography is resumed (step Sb12).

If there is no subject coordinate data outside the non-interference region (step Sb10), that is, if the subject coordinate data is included inside the closed curve defined by the boundary data of the second boundary 153, the scanno imaging is completed. Scannographing is executed until instructed (step Sb13).

When the scanno imaging is completed, a scanno image is generated (step Sb14). The scan range is set using the scanno image according to the instruction of the operator via the input device 59 (step Sb15). At this time, the position information of the gantry main body 11 corresponding to the scan range is output to the system control circuit 57. Further, by setting the scan range, a non-scan target area (non-scan coordinate data) and a scan target area (scan target coordinate data) are set by the upper image and the lower image relating to the scan range.

FIG. 10 is a flowchart showing an example of a gantry control process in a scan performed after scanning.

If the subject coordinate data is not included outside the non-interference region, the gantry main body 11 is moved toward the scan range start position (step Sc1). During the movement of the gantry main body 11, if the scan target area is located outside the non-interference area (step Sc2), the movement of the gantry main body 11 is stopped (step Sc3).

The subject coordinate data is included in the non-interference region, that is, the subject coordinate data is included in the closed curve defined by the boundary data of the second boundary 153, and the movement of the gantry main body 11 via the input device 59. If the instruction is input by the operator, the movement of the gantry main body 11 is restarted (step Sc4).

If the gantry main body 11 has not moved to the scan start position, the processes of steps Sc2 to 4 are repeated (step Sc5). If the gantry main body 11 moves to the scan start position and the scan target area is included in the FOV, that is, the scan target coordinate data is inside the closed curve (FOV) defined by the boundary data of the first boundary 151. If it is included, scanning is started by an operator's scanning start instruction via the input device 59 (step Sc6).

If there is a scan target area outside the FOV (step Sc7), that is, if there is scan target coordinate data outside the closed curve defined by the boundary data of the first boundary 151, the scan is stopped (step Sc8). At this time, if the scan is a helical scan, the movement of the gantry main body 11 is also stopped.

The scan target area is included in the FOV (step Sc9), that is, the scan target coordinate data is included in the closed curve (FOV) defined by the boundary data of the first boundary 151, and the scan is restarted via the input device 59. When the instruction of is input by the operator, the scanning is restarted (step Sc10). If the scan does not resume, the scan ends.

If there is no scan target area outside the FOV (step Sc7), that is, if the scan target coordinate data is included inside the closed curve (FOV) defined by the boundary data of the first boundary 151, an instruction to end the scan is instructed. The scan is executed until there is (step Sc11).

According to the configuration described above, the following effects are obtained.
According to the X-ray computed tomography apparatus 2 according to the present embodiment, a plurality of sensors (subject detectors) are installed in a place other than the gantry main body 11, and the scanno image generated by the scanno imaging is used as a scan target area. The non-scan target area is separated, and based on the boundary position information related to the gantry main body 11 and the subject position information, it is determined whether or not the scan target coordinate data is included in the FOV, and the scan target area is determined. If it extends outside the FOV, the scan can be stopped, and when the scan target area returns to the inside of the FOV, the scan can be restarted according to the instruction of the operator. That is, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the relative positional relationship between the gantry main body 11 and the subject S is determined based on the scanno image and the output of the subject detector. be able to.

Further, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the subject detector is not mounted in the vicinity of the opening 15 of the gantry main body 11, and a non-scanning target is used to avoid interference with the gantry main body 11. It is determined whether or not the area is out of the interference line, and if the non-scan target area is out of the interference line, the vertical movement of the gantry main body 11 is stopped, and if the non-scan target area returns to the interference line, the non-scan target area is returned. The vertical movement of the gantry main body 11 can be restarted.

That is, according to the X-ray computed tomography apparatus 2 according to the present embodiment, at what height the gantry main body 11 is located with respect to the subject S based on the scanno image and the output from the subject detector. By determining whether or not the area outside the FOV is the scan target area, the scan can be stopped or a predetermined warning can be displayed. As a result, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the safety of the subject S is ensured, the scanning time is not long, and unnecessary exposure to the subject S is generated. It is possible to observe the scan target area while suppressing it.

From the above, according to the present embodiment, it is possible to provide the X-ray computed tomography apparatus 1 capable of reducing unnecessary exposure to the subject S without interfering with the subject S and the gantry main body 11. ..

(Third Embodiment)
The difference between the first embodiment and the second embodiment is that the above-mentioned gantry control function is executed in the X-ray computed tomography apparatus capable of scanning the subject in the lying position. In the following description, components having substantially the same function and configuration are designated by the same reference numerals, and duplicate explanations will be given when necessary. FIG. 13 is a diagram showing an example of the configuration of the X-ray computed tomography apparatus 3 according to the present embodiment.

As shown in FIG. 13, the gantry main body 11 in the X-ray computed tomography apparatus 3 is placed on the floor surface 69 of the examination room. The X-ray computed tomography apparatus 3 has a top plate 70 on which the subject S is placed, and a sleeper 71 that supports the top plate 70 so as to be inserted into the opening 15. The top plate 70 on which the subject S is placed is inserted into the opening 15 under the control of the system control circuit 57 when placed during scan imaging or scanno imaging. The gantry main body 11 may move along the Z direction so that the top plate 70 on which the subject S is placed is inserted into the opening 15.

Instead of the upper subject detector 16, the rear subject detector 73 is provided on the rear (rear surface) side of the gantry main body 11 at a position on a substantially extension line of the rotation axis R3 when not tilted, via the support column 75. Be done. The rear subject detector 73 may be provided on the wall surface of the examination room at a position on a substantially extension line of the rotation axis R3 when not tilted. Instead of the lower subject detector 45, the front subject detector 77 is provided on the front (front) side of the gantry main body 11 at a position on a substantially extension line of the rotation axis R3 when not tilted, via the support column 79. Be done. The front subject detector 77 may be provided on the wall surface of the examination room at a position on a substantially extension line of the rotation axis R3 when not tilted. Further, the installation position of the rear subject detector 73 and the front subject detector 77 is not limited to the position on the extension line of the rotation axis R3 when not tilted.

The rear subject detector 73 and the front subject detector 77 are devices capable of detecting the subject S from the Z direction parallel to the rotation axis R3 when not tilted. The posterior subject detector 73 and the anterior subject detector 77 may detect the end portion of the subject S or may detect the contour of the whole body of the subject S. The rear subject detector 73 and the front subject detector 77 are, for example, cameras (movie camera (movie camera), video camera (video camera), etc.). The rear subject detector 73 and the front subject detector 77 may have various distance sensors for determining the distance between themselves and the subject S, and the position of the subject S may be determined. It may be composed of various circuits and optical systems related to motion capture (motion sensor) to be detected.

The rear subject detector 73 and the front subject detector 77 output to the console 50 whether or not the subject S is detected, the relative positional relationship of the subject S with respect to the opening 15, and the like. The rear subject detector 73 and the front subject detector 77 output the rear image and the front image of the subject S to the console 50, respectively. At this time, the relative positional relationship between the position of the subject S in the rear image and the front image and the gantry main body 11 is specified.

As shown in FIG. 13, the rear subject detector 73 and the front subject detector 77 each have a detection range D1 and a detection range D2 capable of detecting the position of the subject S. The rear subject detector 73 and the front subject detector 77 have a detection range D1 and a detection range D2 that can capture a reference position or a reference scale that serves as a reference for the distance between themselves and the subject S, respectively. You may have. The reference position or the reference scale is, for example, an object that becomes immobile when the gantry main body 11 and the top plate 70 are relatively moved. The rear subject detector 73 and the front subject detector 77 may measure the distance to the subject S by detecting the reference scale.

(Mount control function)
In the first embodiment and the modified example, the gantry control function in the present embodiment moves the upper subject detector 16 to the rear subject detector 73, the lower subject detector 45 to the front subject detector 77, and the upper subject detector 77. Since it can be understood by reading the image as a rear image and the lower image as a front image, the description thereof will be omitted. That is, the gantry control mechanism in the present embodiment is the same as that described with the X-ray computed tomography devices 1 and 2 in FIGS. 1 and 7 placed horizontally.

In this embodiment, the movement of the top plate 70 may be controlled by the system control circuit 57 or the like instead of the movement of the gantry main body 11. At this time, the control target is the movement control of the top plate 70 instead of the movement control of the gantry main body 11 in the first embodiment and the modified example. The main storage circuit 55 may store a control mode in which the movement control of the gantry main body 11 in the first control mode and the second control mode is replaced with the movement control of the top plate 70. The description of the movement control of the top plate 70 is omitted because it corresponds to the explanation in which the movement control of the gantry main body 11 is simply replaced with the movement control of the top plate 70.

According to the configuration described above, in addition to the effects described in the other embodiments and modifications described above, the following effects are obtained.
According to the X-ray computed tomography apparatus 3 according to the present embodiment, it is determined whether or not the non-scan target area is out of the interference line in order to avoid interference with the gantry main body 11, and the non-scan target area is the interference line. When the number is out, the movement of the top plate 70 can be stopped, and when the non-scanned area returns within the interference line, the movement of the top plate 70 can be restarted. From the above, according to the present embodiment, there is provided an X-ray computed tomography apparatus 3 capable of reducing unnecessary exposure to the subject S without interfering with the subject S in the lying position and the gantry main body 11. can do.

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

1, 2 ... X-ray computer tomography device, 10, 101 ... gantry device, 11 ... gantry body, 13 ... support, 14, 141 ... horizontal material, 15 ... opening, 16 ... upper subject detector, 17 ... X Wire tube, 19 ... X-ray detector, 21 ... Rotating frame, 23 ... Rotating drive, 25 ... Stand control circuit, 31 ... Stand drive, 39 ... High voltage generator, 41 ... Data acquisition circuit (DAS), 42 ... Open subject detector, 43 ... Mounting table, 45 ... Lower subject detector, 50 ... Console, 51 ... Image reconstruction device, 53 ... Image processing device, 55 ... Main storage circuit, 57 ... System control circuit, 59 ... Input device, 61 ... Display device, 63 ... Judgment circuit, 69 ... Laboratory floor, 70 ... Top plate, 71 ... Sleeper, 73 ... Rear subject detector, 75 ... Support, 77 ... Front subject detector , 79 ... Support, 151 ... First boundary, 153 ... Second boundary (interference line), 155 ... First boundary diameter, 157 ... Second boundary diameter, 161 ... First upper sample detector, 163 ... First 2 Upper subject detector, 451 ... 1st lower subject detector, 453 ... 2nd lower subject detector, 511 ... preprocessing unit, 513 ... projection data storage unit, 515 ... reconstruction calculation unit, A1 ... upper Subject detector detection range, A2 ... Open subject detector detection range, A3 ... Lower subject detector detection range, B1 ... First upper subject detector detection range, B2 ... Second upper subject detector Detector detection range, B3 ... First lower subject detector detection range, B4 ... Second lower subject detector detection range, D1 ... Rear subject detector detection range, D2 ... Front subject detector Detection range, R1 ... central axis, R2 ... horizontal axis, R3 ... rotation axis.

Claims (10)

A gantry that has an X-ray tube and an X-ray detector across the opening and is movable relative to the floor of the examination room in order to photograph the subject by the X-rays emitted from the X-ray tube. When,
The information relating to the first boundary indicating the outer edge of the imaging field of view inside the opening, and the first for preventing interference between the subject and the gantry between the first boundary and the inner surface of the opening. A storage circuit that stores information related to two boundaries,
The X-ray tube is controlled so as to stop the irradiation of X-rays based on the relative positional relationship between the scan target area of the subject and the first boundary, or the non-scan target area of the subject. A control circuit that controls the gantry so as to stop the movement of the gantry based on the relative positional relationship with the second boundary.
A plurality of subject detectors for detecting the subject, and
Based on the output from the subject detector, it is determined whether or not a part of the scan target area is located outside the first region defined by the first boundary, and defined by the second boundary. A determination circuit for determining whether or not a part of the non-scanned area is located outside the second area to be scanned, and a determination circuit.
Equipped with
The control circuit controls the gantry based on the determination result by the determination circuit.
The gantry is a gantry capable of scanning the subject in a standing or sitting position.
The subject detector is provided at least on one of the upper side and the lower side of the opening and on the outer edge of the exterior of the gantry.
The non-scanning target area is a region where the subject cannot be detected by the subject detector provided on the outer edge.
X- ray computed tomography equipment. A gantry that has an X-ray tube and an X-ray detector across the opening and is movable relative to the floor of the examination room in order to photograph the subject by the X-rays emitted from the X-ray tube. When,
The information relating to the first boundary indicating the outer edge of the imaging field of view inside the opening, and the first for preventing interference between the subject and the gantry between the first boundary and the inner surface of the opening. A storage circuit that stores information related to two boundaries,
The X-ray tube is controlled so as to stop the irradiation of X-rays based on the relative positional relationship between the scan target area of the subject and the first boundary, or the non-scan target area of the subject. A control circuit that controls the gantry so as to stop the movement of the gantry based on the relative positional relationship with the second boundary.
A plurality of subject detectors for detecting the subject, and
Based on the output from the subject detector, it is determined whether or not a part of the scan target area is located outside the first region defined by the first boundary, and defined by the second boundary. A determination circuit for determining whether or not a part of the non-scanned area is located outside the second area to be scanned, and a determination circuit.
Equipped with
The control circuit controls the gantry based on the determination result by the determination circuit.
The gantry is a gantry capable of scanning the subject in a standing or sitting state, and scano imaging is performed on the subject.
The subject detector is an X-ray computed tomography apparatus provided on the upper side and the lower side of the opening. The imaging field of view is set using the scanno image obtained by the scanno imaging.
The non-scanning target area is a region in which the scanno image and the subject detected by the subject detector do not match.
The X-ray computed tomography apparatus according to claim 2. A gantry that has an X-ray tube and an X-ray detector across the opening and is movable relative to the floor of the examination room in order to photograph the subject by the X-rays emitted from the X-ray tube. When,
The information relating to the first boundary indicating the outer edge of the imaging field of view inside the opening, and the first for preventing interference between the subject and the gantry between the first boundary and the inner surface of the opening. A storage circuit that stores information related to two boundaries,
The X-ray tube is controlled so as to stop the irradiation of X-rays based on the relative positional relationship between the scan target area of the subject and the first boundary, or the non-scan target area of the subject. A control circuit that controls the gantry so as to stop the movement of the gantry based on the relative positional relationship with the second boundary.
Equipped with
The storage circuit controls the X-ray tube so as to stop the irradiation of X-rays by the X-ray tube when a part of the scan target area exceeds the first boundary, or the non-scan target area. The first control mode for controlling the gantry so as to stop the movement of the gantry when a part of the pedestal exceeds the second boundary, and the gantry when the contour of the subject exceeds the second boundary. The second control mode that controls the gantry so as to stop the movement of the
When the imaging field of view changed by the setting by the operator or the inclination of the gantry with respect to the floor surface is narrower than the contour, the control circuit controls the gantry in the second control mode and is set by the operator or said. When the imaging field of view changed by the inclination of the gantry with respect to the floor surface is wider than the contour, the gantry is controlled in the first control mode.
X-ray computed tomography equipment. The control circuit controls the X-ray tube so as to stop the irradiation of X-rays by the X-ray tube when a part of the scan target area exceeds the first boundary, or the non-scan target area. When a part of the above crosses the second boundary, the gantry is controlled so as to stop the movement of the gantry.
The X-ray computed tomography apparatus according to any one of claims 1 to 4. A plurality of subject detectors for detecting the subject, and
Based on the output from the subject detector, it is determined whether or not a part of the scan target area is located outside the first region defined by the first boundary, and defined by the second boundary. A determination circuit for determining whether or not a part of the non-scanned area is located outside the second area to be scanned, and a determination circuit.
Further equipped,
The control circuit controls the gantry based on the determination result by the determination circuit.
The X-ray computed tomography apparatus according to claim 4 or 5. When the control circuit determines that a part of the scan target area is located outside the first region in the scan for the subject, or the non-scan target area outside the second region. If it is determined that a part of the gantry is located, the gantry is controlled to stop the scan and the movement of the gantry.
The X-ray computed tomography apparatus according to any one of claims 1 to 3 and 6. After the scan is stopped, the control circuit performs the scan in response to the fact that the scan target area is included in the area defined by the first boundary and the input of the scan restart instruction. Control the gantry to resume,
The X-ray computed tomography apparatus according to claim 7. The subject detector is at least one of a camera, a detector using sound waves, a detector using infrared rays, and a detector using a magnetic field.
The X-ray computed tomography apparatus according to any one of claims 1 to 3 and 6 to 8. The subject detector detects the edge of the subject or the contour of the subject.
The X-ray computed tomography apparatus according to any one of claims 1 to 3 and 6 to 9.

Images