JP2017077457A - X-ray computed tomography apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray computed tomography apparatus capable of preventing interference between a subject and the gantry and at the same time reducing unnecessary exposure of the subject to radiation.SOLUTION: An X-ray computed tomography apparatus 1 according to the embodiment comprises: a gantry 11 having an X-ray tube and an X-ray detector disposed facing each other across an opening and movable relative to an examination room floor surface to image a subject with X-rays illuminated from the X-ray tube; a storage circuit 55 for storing information of a first boundary indicative of an outer rim of an imaging field inside the opening and information of a second boundary located between the first boundary and an inner surface of the opening to prevent interference between the subject and the gantry; and a control circuit for controlling the X-ray tube to stop illumination of X-rays based on a relative positional relationship between a scan target area of the subject and the first boundary or for controlling the gantry to stop movement of the gantry based on a relative positional relationship between a non-scan target area of the subject and the second boundary.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an X-ray computed tomography apparatus.

  Conventionally, X-ray computed tomography is usually performed in a prone position where a patient lies on a bed. On the other hand, X-ray computed tomography of a subject in a standing position is desired.

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

  Therefore, in order to confirm in advance that there is no interference between the subject or chair-type bed or the like and the gantry body when the gantry body is lowered from the ceiling side in the X-ray CT apparatus placed horizontally. 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 (aperture opening) into which a subject is inserted.

  At this time, using the interference prevention device, the predetermined radius is set to the same radius as the imaging range to prevent unnecessary exposure, and imaging is stopped even when a portion other than the imaging area is out of the imaging range. There is a problem that it is necessary to take measures such as, and the photographing time becomes long.

Japanese Patent Laid-Open 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 a gantry.

  The X-ray computed tomography apparatus according to this 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 examination room in order to image the subject by X-rays emitted from the X-ray tube. Is possible. The memory circuit includes information on a first boundary indicating an outer edge of the imaging field within the opening, and interference between the subject and the gantry between the first boundary and the inner surface of the opening. And information related to the second boundary for preventing. The control circuit controls the X-ray tube to stop X-ray irradiation based on a relative positional relationship between the scan target region of the subject and the first boundary, or controls the non-existence of the subject. Based on the relative positional relationship between the scan target area and the second boundary, the gantry is controlled to stop the movement of the gantry.

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 illustrating an example of a detection range of an object by an upper object detector provided on the horizontal member according to the first embodiment. FIG. 3 is a perspective view illustrating the gantry body, the first boundary, and the second boundary according to the first embodiment. FIG. 4 is a diagram illustrating an example of a detection range of a subject by an open subject detector provided in the vicinity of the gantry body according to the first embodiment. FIG. 5 is a detailed diagram for explaining FIG. 4 in more detail according to the first embodiment. FIG. 6A is a flowchart illustrating a processing procedure of a gantry control process according to the first embodiment. FIG. 6B is a flowchart illustrating the 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 the second embodiment. FIG. 8 is a perspective view showing a scan range according to the second embodiment. FIG. 9A is a flowchart illustrating a processing procedure of a gantry control process for scanogram collection according to the second embodiment. FIG. 9B is a flowchart illustrating a processing procedure of a gantry control process for scanogram collection according to the second embodiment. FIG. 10 is a flowchart illustrating a gantry control process in a scan performed after scano imaging according to the second embodiment. FIG. 11 relates to a modification of the first embodiment, and is a diagram relating to a description of a control mode relating to the movement of the gantry body. FIG. 12 is a flowchart illustrating an example of a procedure for setting a control mode related to the movement of the gantry body according to the modification of the first embodiment. FIG. 13 is a diagram showing a configuration of an X-ray computed tomography apparatus according to the third embodiment.

(First embodiment)
The X-ray computed tomography apparatus according to this embodiment will be described below 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 this 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. 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 to each other in a wired or wireless manner so that they can 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 state or a sitting state. The console 50 is a computer that controls the gantry device 10.

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

  As shown in FIG. 1, the gantry body 11 is a substantially cylindrical structure in which an opening 15 having a field of view (FOV) is formed. As shown in FIG. 1, the gantry 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 body 11 is movable relative to the floor surface of the examination room in order to image the subject with X-rays emitted from the X-ray tube 17. Hereinafter, although the movement of the gantry body 11 will be described, the mounting table 43 may be moved.

  More specifically, the gantry body 11 includes a main frame (not shown) formed of a metal such as aluminum, and a rotating frame 21 supported by the main frame so as to be rotatable around a central axis R1 via a bearing or the like. It has further. 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 be in sliding contact with the annular electrode.

  The rotating frame 21 is a metal frame formed in a ring shape with a metal such as aluminum, and, for example, an X-ray tube 17 and an X-ray detector 19 are attached thereto. For example, 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 by 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 driving device 23 generates power for rotating the rotating frame 21 in accordance with 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 of the drive signal from the gantry control circuit 25. The rotary drive device 23 is realized by a motor such as a direct drive motor or a servo motor, for example. The rotation drive device 23 is accommodated in the gantry body 11, for example.

  As shown in FIG. 1, the support column 13 is a base that supports the gantry body 11 away from the floor surface. The support | pillar 13 is installed in a floor surface. The column 13 is a structure that supports the gantry body 11 so as to be slidable in the longitudinal direction of the column 13. The support column 13 has, for example, a columnar shape such as a columnar shape or a prismatic shape. The support column 13 is formed of an arbitrary substance such as plastic or metal. The column 13 is attached to the side surface of the gantry body 11. The column 13 has a structure capable of supporting the gantry 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 state or the sitting state. The support column 13 has a robust structure for supporting the gantry body 11.

  In addition, the support | pillar 13 is not limited to the said structure. For example, the column 13 has a columnar shape, but the present embodiment is not limited to this. For example, the column 13 may have any shape such as a U shape as long as it can support at least one side of the gantry body. Note that the 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 column 13 may be configured to support the gantry body 11 so as to be rotatable about the horizontal axis R2. Specifically, the column 13 and the gantry body 11 are connected to each other through a bearing or the like so that the gantry body 11 can rotate about the horizontal axis R2.

  Further, the support column 13 is not limited 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 about the horizontal axis R2. It may be stationary to face any angle.

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

  The column 13 receives the power from the gantry driving device 31 and slides the gantry body 11 along the longitudinal direction D with respect to the column 13. The support column 13 receives power from the gantry driving device 31 and lowers the gantry body 11 from the ceiling side of the CT examination room toward the mounting table 43 before the start of scanning of the subject. The column 13 causes the gantry driving device 31 to raise the gantry body 11 from the scan position toward the ceiling of the CT examination room after the scan of the subject is completed.

  Note that a driving device for tilting the gantry body 11 (hereinafter referred to as a tilt driving device) may be connected to the column 13. The tilt driving device generates power for rotating the gantry body 11 about the horizontal axis R <b> 2 in accordance with a drive signal from the gantry control circuit 25. Specifically, the tilt drive device generates power by driving at a rotational speed corresponding to the duty ratio of the drive signal from the gantry control circuit 25. The column 13 receives power from the tilt driving device and rotates the gantry body 11 about the horizontal axis R2. The gantry driving device 31 and the tilt driving device are realized by a motor such as a servo motor, for example.

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

  The upper object detector 16 is preferably provided at a position on the central axis R <b> 1 in the horizontal member 14. That is, the upper analyte detector 16 is provided above the opening 15. The upper subject detector 16 is a device that can detect a subject from directly above the subject along the vertical Y direction. The upper subject detector 16 may detect the end of the subject (the top of the head, the shoulder, the end of the limb, the elbow, the knee), or may detect the contour of the whole subject. The upper object detector 16 is, for example, a camera (movie camera, video camera, etc.).

  The upper object 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 object. ). The upper object detector 16 may be configured by various circuits and an optical system related to motion capture (motion sensor) for detecting the position of the object.

  The upper object detector 16 outputs to the console 50 the presence / absence of detection of the object, the relative positional relationship of the object with respect to the opening 15, the upper image obtained by photographing the object, and the like. At this time, the relative positional relationship between the position of the subject in the upper image and the gantry body 11 is specified. The upper object detector 16 may output the presence / absence of the detection of the object, the relative positional relationship, the upper image, and the like to the gantry control circuit 25.

  As shown in FIG. 1, the upper object detector 16 has a detection range A1 in which the position of the object can be detected. Note that the upper object detector 16 may have a detection range A1 in which a reference position or a reference scale serving as a reference for the distance between itself and the object can be photographed. The reference position or the reference scale is, for example, an object that does not move when the gantry body 11 moves, and is provided on the mounting table 43, for example. The upper object detector 16 may measure the distance from the object by detecting a reference scale.

  When the horizontal member 14 is not provided on the gantry device 10, the upper object detector 16 may be provided directly above the opening 15 and on the ceiling of the CT examination room. At this time, the upper object 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 object detectors 16 may be provided on the horizontal member 14 or the ceiling of the CT examination room.

  FIG. 2 is a diagram illustrating an example of a detection range of the subject S by the upper subject detector 16. A dashed-dotted line 151 in FIG. 2 indicates a boundary between the imaging range and the non-imaging range of the subject S (hereinafter referred to as a first boundary) in the region (opening region) of the opening 15 of the gantry body 11. . The inside of the one-dot chain line 151 corresponds to FOV (first region). That is, the inside of the one-dot chain line 151 corresponds to a range that can be reconstructed by the image reconstruction device 51 described later.

  A 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 and preventing interference between the subject S and the gantry body 11. ing. The outside of the interference line 153 indicates a region 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 body 11 (hereinafter referred to as a non-interference region (second region)).

  An area between the first boundary 151 and the second boundary 153 is an area in which projection data necessary for reconstruction may not be prepared in reconstruction of volume data, for example, in a scan (CT scan) on the subject S Or it corresponds to a non-reconstruction area. The volume data corresponding to the area between the first boundary 151 and the second boundary 153 is referred to as a mask area, for example.

  FIG. 3 is a perspective view showing the gantry body 11, the first boundary 151, and the second boundary 153. A range 155 in FIG. 3 indicates the diameter of the first boundary 151. The diameter 155 of the first boundary 151 is substantially equal to the diameter of the FOV. A 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. A width Rw in FIG. 3 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 receives the application of a high voltage from the high voltage generator 39 and generates X-rays. The high voltage generator 39 is attached to the rotating frame 21, for example. 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 power supplied from the power supply device (not shown) of the gantry 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 a 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 it into an electrical signal having a peak value corresponding to the detected X-ray intensity. Each X-ray detection element has, for example, a scintillator and a photoelectric converter. The scintillator receives X-rays and generates fluorescence. The photoelectric converter converts the generated fluorescence into a charge pulse. The charge pulse has a peak value corresponding to the intensity of the X-ray.

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

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

  The integration circuit integrates the electric signal from the X-ray detection element over a predetermined view period to generate an integration signal. The A / D converter performs A / D conversion on the generated integration signal, and generates digital data having a data value corresponding to the peak value of the integration signal. The converted digital data is called raw data. The 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 detection element. The raw data is supplied to the console 50 via, for example, a non-contact data transmission device (not shown) accommodated in the gantry body 11.

  The gantry body 11 includes not only the X-ray tube 17, the X-ray detector 19, the rotating frame 21, the main frame, the power supply device, the high voltage generator 39, and the data collection 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. A fan for air conditioning may be attached to the gantry body 11.

  An opening analyte detector 42 is provided on the outer edge of the opening 15 in the exterior of the gantry body 11. The opening object detector 42 is a device that can detect a part of the object S located in the opening 15. The opening subject detector 42 may detect the end of the subject S (the top of the head, the shoulder, the end of the limb, the elbow, the knee), or may detect the contour of the whole body of the subject. The aperture object detector 42 is, for example, a camera (movie camera, video camera, etc.).

  The opening object detector 42 includes various distance sensors (optical (infrared ray, visible light) sensor, magnetic field sensor, sound wave sensor, ultrasonic sensor, etc.) for determining the distance between itself and the object S. You may have. Note that the aperture object detector 42 may be configured by various circuits and optical systems related to motion capture for detecting the position of the object S.

  The opening object detector 42 outputs to the console 50 the presence / absence of detection of the object S in the opening 15, the relative positional relationship of the object S with respect to the opening 15, the opening image obtained by photographing the object S, and the like. To do. At this time, the relative positional relationship between the position of the subject S and the gantry body 11 in the aperture image is specified. The opening object detector 42 may output the presence / absence of detection of the object S, the relative positional relationship, the opening image, and the like to the gantry control circuit 25.

  As shown in FIG. 1, the opening object detector 42 has a detection range A <b> 2 in which the position of the object S can be detected in the opening 15. Note that the aperture object detector 42 may have a detection range A2 in which a reference position or a reference scale that is a reference for the distance between itself and the object S can be photographed. The reference position or the reference scale is, for example, an object that does not move when the gantry body 11 moves, and is provided on the mounting table 43, for example. The opening object detector 42 may measure the distance from the object S by detecting a reference scale. A plurality of opening object detectors 42 may be provided on the outer edge of the opening 15 on the exterior of the gantry body 11.

  FIG. 4 is a diagram illustrating an example of a detection range of the subject S by the opening subject detector 42. A range B in FIG. 4 indicates a range (hereinafter referred to as a non-scan target region) that is outside the imaging target (undetectable by the aperture subject detector 42) in the scan of the subject S. In the scan of the subject S, it is required that the non-scan target area does not come out of the interference line (second boundary) 153. A range C in FIG. 4 indicates a range of an imaging target (hereinafter referred to as a scan target region) in scanning with respect to the subject S. The scan target area is required not to come out of 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-scan target area is included in the non-interference area defined by the interference line 153. In addition, 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 driving device 23, and the gantry driving device 31 in accordance with control from the system control circuit 57 of the console 50. For example, the gantry control circuit 25 controls various devices mounted on the gantry body 11 and the gantry device 10 according to the determination result determined by the determination circuit 63 described later. Specific control of the gantry device 10 by the gantry control circuit 25 will be described in detail later.

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

  In addition, the gantry control circuit 25 includes an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and other complex programmable logic devices (ComplexDevProG). CPLD) and a simple programmable logic device (SPLD).

  The processing device implements the above functions by reading and executing a 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 a program incorporated in the circuit.

  The gantry control circuit 25 may be provided on the column 13 or the gantry 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 input via the input device 59 provided on the exterior of the gantry body 11 and information input. Also 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 state or a sitting state. That is, the subject S in a standing state or a sitting state is placed on the placing table 43. The mounting table 43 has a robust structure in order to support the subject S in a standing or sitting position. The mounting table 43 is formed of an arbitrary substance such as plastic or metal.

  Note that the upper end portion of the mounting table 43 may be made of an artifact-free material, that is, a material having a small X-ray attenuation coefficient. The mounting table 43 has a size corresponding to the diameter of the opening 15 immediately below the opening 15. As a result, when the gantry body 11 is lowered to the lowermost end of the moving range that can be slid along the longitudinal direction D of the support column 13, the scan is performed up to the lowermost portion of the subject S placed on the mounting table 43. Can be executed.

  A lower object detector 45 is provided on the outer edge of the mounting table 43. That is, the lower object detector 45 is provided below the opening 15. The lower object detector 45 is an apparatus that can detect a part of the object S located in the opening 15. The lower object detector 45 detects the blind spots of the detection range A1 of the upper object detector 16 and the detection range A2 of the open object detector 42 in order to prevent the object S from being caught by the lowering of the gantry body 11. In order to eliminate, it is provided on the mounting table 43.

  The lower subject detector 45 may detect the end of the subject S (the top of the head, the shoulder, the end of the limb, the elbow, the knee), or may detect the contour of the whole subject. For example, the lower object detector 45 is a camera (movie camera, video camera, etc.), for example. When the mounting table 43 is not installed, the lower object 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 object detector 45 includes various distance sensors (such as an optical (infrared, visible light) sensor, a magnetic field sensor, a sound wave sensor, and an ultrasonic sensor) for determining the distance between itself and the object S. You may have. Further, the lower object detector 45 may be configured by various circuits and an optical system related to motion capture for detecting the position of the object S.

  The lower object detector 45 outputs to the console 50 the presence / absence of detection of the object S in the opening 15, the relative positional relationship of the object S with respect to the opening 15, the lower image obtained by photographing the object S, and the like. To do. At this time, the relative positional relationship between the position of the subject S and the gantry body 11 in the lower image is specified. The lower object detector 45 may output the presence / absence of the detection of the object S, the relative positional relationship, the lower image, and the like to the gantry control circuit 25.

  As shown in FIG. 1, the lower object detector 45 has a detection range A <b> 3 in which the position of the object S can be detected in the opening 15. The lower object detector 45 may have a detection range A3 in which a reference position or a reference scale serving as a reference for the distance between itself and the object S can be photographed. The reference position or reference scale is, for example, an object that does not move when the gantry body 11 is moved, and is provided, for example, on the ceiling of the CT examination room, the horizontal member 14 or the like. The lower object detector 45 may measure the distance from the object S by detecting a reference scale. A plurality of lower object 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 storage 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 included. Data communication among 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. Done.

  The image reconstruction device 51 reconstructs a CT image related 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 the system control circuit 57, for example.

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

  The reconstruction calculation unit 515 generates a CT image representing the spatial distribution of CT values related to the subject S based on the projection data. As an image reconstruction algorithm, an FBP (filtered back projection) method, an analytical image reconstruction method such as a CBP (convolution back projection) method, an ML-EM (maximum likelihood projection maximized) method, an OS-EM (erroneous) An existing image reconstruction algorithm such as a statistical image reconstruction method such as an extraction maximum method may be used.

  The image reconstruction device 51 includes, as hardware resources, a processing device (processor) such as a CPU, MPU, or GPU (Graphics Processing Unit) and a storage device (memory) such as a ROM or RAM. The image reconstruction device 51 may be realized by an ASIC, FPGA, CPLD, or SPLD. The processing device implements the functions of the preprocessing unit 511 and the reconstruction calculation unit 515 by reading and executing a 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 apparatus implements the functions of the preprocessing unit 511 and the reconstruction calculation unit 515 by reading and executing a program incorporated in the circuit. In addition, a dedicated hardware circuit that functions as the pre-processing 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 reconstruction 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 Reconstruction) processing, CPR (Curved MPR) processing, MIP on the CT image. A display image is generated by performing 3D image processing such as (Maximum Intensity Projection) processing. The image processing device 53 outputs the generated display image to the display device 61.

  The image processing device 53 receives a three-dimensional object image (object to be detected) from outputs from a plurality of object detectors (upper object detector 16, open object detector 42, lower object detector 45). Specimen coordinate data) may be generated. Further, the image processing apparatus 53 may extract the end of the subject S using the outputs (images) from the plurality of subject detectors, or may extract the outline of the whole body of the subject S. Good.

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

  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 unit that reads / writes various information from / to 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 subjected to image processing by the image processing device 53.

  The main memory circuit 55 stores the upper image generated by the upper object detector 16, the opening image generated by the opening object detector 42, and the lower image generated by the lower object detector 45. The main memory circuit 55 stores a scan plan transmitted from a radiology information system (RIS) via an interface (not shown) and a network.

  The main memory circuit 55 controls the gantry device 10 based on the scan-related program according to the present embodiment, the outputs from the plurality of object detectors, and the first boundary 151 and the second boundary (interference line) 153 set in advance. The gantry control program to be controlled is stored. The main memory circuit 55 stores programs and determination conditions related to various determinations executed by the determination circuit 63.

  The main memory circuit 55 stores a coordinate system related to the gantry device 10 (hereinafter referred to as a gantry coordinate system). In the gantry coordinate system, the main memory circuit 55 includes coordinate data (hereinafter referred to as first boundary data) regarding the first boundary 151 and coordinate data (hereinafter referred to as second boundary data) regarding the second boundary (interference line) 153. ) Is memorized. The main memory circuit 55 may store a coordinate specifying program that specifies (extracts) coordinate data of a part of the subject S (hereinafter referred to as subject coordinate data) in each of the upper image, the aperture 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 top of the head, the shoulder, the end of the limb, the elbow, and the knee.

  The main memory circuit 55 stores the positional relationship between the first boundary 151 and the second boundary 153 and the gantry device 10. For example, the main memory circuit 55 includes the subject S and the gantry body 11 between the first boundary and the inner surface of the opening 15 between the information related to the first boundary indicating the outer edge of the imaging field within the opening 15. And information related to the second boundary for preventing interference with the information. The first boundary 151 and the second boundary (interference line) 153 can be appropriately changed via the input device 59. The main memory 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. The main memory circuit 55 stores a predetermined warning corresponding 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 that alerts the operator.

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

  The system control circuit 57 controls various devices and various circuits in accordance with various commands input via the input device 59 and information input. The system control circuit 57 may execute a function related to the determination circuit 63. The system control circuit 57 reads out a warning corresponding to the determination result from the main memory 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 accepts various commands and information input 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 input by the operator and information input to the system control circuit 57. The input device 59 may be provided in the console 50 or may be provided in 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, resets, and the like regarding the first boundary 151 and the second boundary (interference line) 153. Further, the input device 59 inputs an instruction to start scanning, restart scanning, and the like. Note that the input device 59 may input the setting and change of a specified part of the subject S in each of the upper image, the opening image, and the lower image.

  The display device 61 includes 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 used as appropriate. 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 the accuracy of the scan when the non-scan 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 using the upper image and the lower image before the gantry body 11 is moved (lowered) to the scan imaging position. The determination circuit 63 determines the position of the subject S in each of the upper image and the lower image and the second boundary while the subject S is placed on the placement table 43 and the gantry body 11 moves (lowers) to the scan imaging position. 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. In the above determination, an aperture image may be further used.

  Specifically, the determination circuit 63 extracts (specifies) subject coordinate data in each of the upper image, the opening 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 object coordinate data (hereinafter referred to as scan target coordinate data) included in the imaging range in the aperture image when the gantry body 11 reaches the scan imaging position.

  Further, the non-scan target area corresponds to object 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 body 11 reaches the scan imaging position. . Thereby, in the subject S, the scan target area and the non-scan target area are separated. The extracted subject coordinate data is data indicating coordinates with respect to the gantry coordinate system.

  Next, the determination circuit 63 determines whether the scan target area is located in the first area (FOV) by comparing the scan target coordinate data with the first boundary data. Further, the determination circuit 63 compares the non-scan coordinate data and the second boundary data with respect to each of the upper image and the lower image, thereby determining whether or not the non-scan target area is located in the second area (non-interference area). Determine whether. That is, the determination circuit 63 performs determination using the coordinates (boundary position information) of the first boundary 151 and the second boundary 153 in the gantry coordinate system and the object coordinate data (object position information). Hereinafter, the determination by the determination circuit 63 will be described in more detail.

  Based on the positional relationship between the position of the subject S and the first boundary 151 in the aperture image, the determination circuit 63 uses the first region (FOV) as the scan target region when the gantry body 11 reaches the scan imaging position. It is determined whether it is located within. 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.

  The determination circuit 63 determines whether the scan target region is based on the positional relationship (coordinate relationship) between the position of the scan target region in the aperture image and the first boundary 151 during the scan of the scan target region of the subject S by the gantry body 11. It is determined whether or not 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 body 11 at the scan photographing position and the scan of the scan target region. It is determined whether the scan target area is located in the FOV.

  The determination circuit 63 determines whether the non-scan target is based on the positional relationship (coordinate relationship) between the position of the non-scan target region in each of the upper image and the lower image and the second boundary (interference line) 153 during the scan of the scan target region. It is determined whether or not the area is located within the non-interference area. That is, the determination circuit 63 determines that the non-scan target area is located in the non-interference area based on the relative positional relationship (coordinate relation) between the non-scan coordinate data and the second boundary data during the scan with respect to the scan target area. It is determined whether or not.

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

(Base control function)
The gantry control function is a function of controlling the gantry device 10 in order to control movement and scanning of the gantry body 11 related to scanning based on the determination result output from the determination circuit 63. Processing related to the gantry control function is called gantry control processing. Hereinafter, functions of the gantry control circuit 25 relating to the gantry control processing 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. The gantry control circuit 25 is configured to stop 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 in the scan performed on the subject S by the gantry main body 11. The apparatus 10 is controlled. In other words, the gantry control circuit 25 controls the gantry device 10 in order to stop the scan and the movement of the gantry body 11 in accordance with 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 to stop the X-ray irradiation based on the relative positional relationship between the scan target region of the subject S and the first boundary. The gantry control circuit 25 controls the gantry 11 to stop the movement of the gantry 11 based on the relative positional relationship between the non-scan target region of the subject S and the second boundary. For example, the gantry control circuit 25 controls the X-ray tube 17 to stop the X-ray irradiation by the X-ray tube 17 when a part of the scan target region exceeds the first boundary. The gantry control circuit 25 controls the gantry 11 to stop the movement of the gantry 11 when a part of the non-scan target region exceeds the second boundary.

  Specifically, when it is determined that the subject S placed on the placement table 43 is positioned in the non-interference area before the gantry body 11 is lowered to the scan imaging position, the gantry control circuit 25 In response to an input of an instruction to move the gantry body 11 to the scan imaging position, the gantry driving device 31 is controlled to lower the gantry body 11 to the scan imaging position. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the gantry body 11 starts to descend toward the scan imaging position.

  During the movement (lowering) of the gantry body 11 to the scan photographing position, the non-scan target area is located in the non-interference area, that is, the non-interference area in which the non-scan coordinate data is defined by the second boundary data. When it is determined that it is located inside, the gantry control circuit 25 controls the gantry driving device 31 and the like in order to continue the descent of the gantry body 11. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the descent of the gantry body 11 is continued toward the scan imaging position.

  During movement (lowering) of the gantry body 11 to the scan imaging position, a part of the subject S is located outside 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 position is located outside, the gantry control circuit 25 controls the gantry driving device 31 in order to stop the movement of the gantry body 11. The descent of the gantry body 11 is stopped by the control of the gantry control circuit 25 with respect to the gantry driving device 31.

  After stopping the descent of the gantry body 11, it is determined that the non-scan target area is located within the non-interference area, that is, the non-scan coordinate data is located within the non-interference area defined by the second boundary data. In such a case, the gantry control circuit 25 controls the gantry driving device 31 in order to move the gantry body 11 again to the scan photographing position in response to an instruction to resume movement via the input device 59. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the gantry body 11 resumes descent toward the scan imaging position.

  When it is determined that the scan target area is located within the FOV after the gantry body 11 reaches the scan shooting position, that is, the scan target coordinate data is located within 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 region 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 with respect to the high voltage generator 39 and the rotary drive device 23 and the like. When the scan to be started is a conventional scan, the gantry body 11 does not move. When the scan to be started is a helical scan, the gantry control circuit 25 further controls the gantry driving 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 of the scan target area, the gantry control circuit 25 controls the gantry device 10 to continue the scan. During the scan, the non-scan target area is outside the detection range of the aperture object 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 the scan, the scan is continued 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, that is, the scan target coordinate data is located outside the FOV defined by the first boundary data during the scan of the scan target area The gantry control circuit 25 controls the gantry device 10 to stop scanning. Specifically, the gantry control circuit 25 controls the high voltage generator 39 in order to stop the X-ray exposure to the scan target region 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 driving device 23 in order to stop the rotation of the rotating frame 21.

  When the scan being executed is a helical scan, the gantry control circuit 25 controls the gantry driving device 31 in order to stop the movement of the gantry body 11. The movement of the gantry body 11 during scanning is stopped by the control of the gantry control circuit 25 with respect to the gantry driving 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 in response to the scan restart instruction via the input device 59. The high voltage generator 39 and the rotary drive device 23 are controlled. The scan is resumed with respect to the scan target area by the control of the gantry control circuit 25 with respect to the high voltage generator 39, the rotary drive device 23, and the like.

6A and 6B are flowcharts illustrating an example of the processing procedure of the gantry control processing.
A first boundary 151 and a second boundary 153 are set (step Sa1). At this time, the first boundary data and the second boundary data are output from the main memory circuit 55 to the determination circuit 63. A 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 processing of step Sa2, the upper object detector 16 generates an upper image. In addition, an aperture image is generated by the aperture object detector 42 (step Sa3). Further, the lower object 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. Thereby, a non-scan target area is specified. Also, scan target coordinate data is extracted from the aperture image. The extracted scan target coordinate data is associated with the scan target area of the subject S. Thus, the scan target area is specified.

  Non-scanned coordinate data relating to the upper image and the lower image is compared with the second boundary data. Thus, if the subject S is included in the non-interference area, the gantry body 11 is lowered toward the scanning imaging position in response to the operator's gantry lowering instruction via the input device 59 (Step S1). Sa4).

  If there is a non-scan target area outside the non-interference area in the upper image (step Sa5), that is, if there is non-scan coordinate data outside the closed curve defined by the boundary data of the second boundary 153, the gantry body 11 is lowered. 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 instruction to resume the descent is input through the input device 59, the descent of the gantry body 11 is resumed. (Step Sa7).

  If there is no non-scan target area outside the non-interference area in the upper image (step Sa5), the gantry body 11 is lowered to the scan photographing 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, A scan is started by an operator's scan 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 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 the operator can be notified that “the scan target area has come out from 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 inside of the closed curve (FOV) defined by the boundary data of the first boundary 151, and via the input device 59. When a scan resumption instruction is input by the operator (step Sa14), the scan is resumed. If the scan is not resumed, 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 in the closed curve defined by the boundary data of the first boundary 151 (FOV), the scan The scan is executed until an end instruction is given (step Sa15).

According to the configuration described above, the following effects can be obtained.
According to the X-ray computed tomography apparatus 1 according to the present embodiment, boundary position information related to the gantry body 11 of the X-ray computed tomography apparatus 1 having a sensor (subject detector) for detecting the object S. And the object position information, it is determined whether the scan target coordinate data is included in the FOV. If the scan target area protrudes outside the FOV, the scan is stopped, and the scan target area is changed to the FOV. Scanning can be resumed when returning to the inside. In addition, a predetermined warning can be displayed when the gantry body 11 is stopped and scanning is stopped.

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

  That is, according to the X-ray computed tomography apparatus 1 according to the present embodiment, the apparatus itself recognizes the height of the gantry body 11 with respect to the subject S and goes out of the FOV. Can be stopped or a predetermined warning can be displayed. Thereby, according to the X-ray computed tomography apparatus 1 according to the present embodiment, the safety for the subject S is ensured while the scan time is not prolonged and the occurrence of unnecessary exposure to the subject S is suppressed. However, the scanning target area can be observed.

  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 causing the subject S and the gantry body 11 to interfere with each other. .

(Modification)
The present modification is to execute a gantry control function by selecting a control mode for controlling the movement of the gantry body 11 in accordance with a change in the imaging field of view.

  The main memory 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 is controlled. This is a control mode for controlling the gantry body 11 to stop the movement of the gantry body 11 when the section exceeds the second boundary. The second control mode is a control mode for controlling the gantry body 11 to stop the movement of the gantry body 11 when the contour of the subject S exceeds the second boundary. The main memory 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 size of the imaging field of view is changed by, for example, an operation for setting a scan range for a scanogram on the screen at the time of the scan plan displayed on the display device 61. The input device 59 inputs an instruction for determining the changed imaging field of view. The input device 59 outputs the determined imaging visual field size to the determination circuit 63.

  The input device 59 inputs an instruction to tilt the gantry 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 body 11, or by an operation for setting the scan range tilt with respect to the scanogram on the screen at the time of the scan plan displayed on the display device 61. It may be entered. The input device 59 outputs the size of the imaging visual field corresponding to the tilt angle according to the tilt instruction to the determination circuit 63. Note that the size of the imaging visual field according to the tilt angle may be determined by the system control circuit 57 using the correspondence table stored in the main memory circuit 55. For example, when the imaging field of view on the plane parallel to the rotation axis of the rotating frame 21 and the vertical direction is a rectangle, the shape (size) of the imaging field of view due to the tilt of the gantry body 11 is rotated according to the tilt angle. Of the four vertices of the rectangle, a straight line passing through each of the two vertices closest to the rotation axis and parallel to the rotation axis is a parallelogram obtained by cutting the rotated rectangle.

  The determination circuit 63 compares the contour of the subject S in the upper image and the opening 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 performs 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 seen from the Y direction. LL shown in FIG. 11 indicates the maximum imaging field of view. The maximum imaging visual field LL includes the contour of the subject S. L shown in FIG. 11 indicates an imaging field that is narrower than the maximum imaging field LL. The imaging visual field L includes the contour of the subject S in the same manner as the maximum imaging visual field LL. In the imaging field LL and the imaging field L, the determination circuit 63 determines that the contour of the subject S is included in the imaging field. 11 indicates an imaging field that is narrower than the imaging field L. The imaging field M does not include the contour of the subject S. In the imaging field M, the determination circuit 63 determines that the contour of the subject S is not included in the imaging field.

  The gantry control circuit 25 reads 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 body 11 in the second control mode. The gantry control circuit 25 reads 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 body 11 in the first control mode. The movement control of the gantry body 11 in the first control mode or the second control mode may be executed by the system control circuit 57.

(Base control function)
The gantry control function according to the present modification is a function for controlling the gantry device 10 to control the movement and scanning of the gantry body 11 based on the determination result according to the change in the imaging field of view. FIG. 12 is a flowchart illustrating an example of a procedure for setting a control mode related to the movement of the gantry 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). Information on the contour of the subject S is output to the determination circuit 63. An input for changing the imaging field of view or the tilt of the gantry body 11 is input via the input device 59 (step Sd2). When the tilt of the gantry body 11 is input, the imaging field of view is set according to the tilt angle (step Sd3). After setting the imaging field according to the tilt angle or inputting the imaging field, it is determined using the contour image whether or not the contour of the subject S is included in the imaging field (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 inclusion determination input from the determination circuit 63 as a trigger to store a program relating to the first control mode in the main memory circuit. Read from 55. Thereby, the movement control of the gantry 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 a program related to the second control mode in the main memory circuit Read from 55. Thereby, the movement control of the gantry body 11 is set as the second control mode (step Sd6). The movement of the gantry body 11 is started in the set control mode (step Sd7).

According to the configuration described above, the following effects can be obtained.
According to the X-ray computed tomography apparatus 1 according to the present embodiment, it is possible to select and set a control mode related to the movement control of the gantry body 11 in accordance with 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 changed according to the change of the imaging field of view according to the operator's instruction or the change of the imaging field of view accompanying the tilt of the gantry body 11 By comparing with the contour of S, it can be determined whether or not the contour of the subject S is included in the imaging field of view, and the control mode in the movement of the gantry body 11 can be determined (switched). Thereby, according to the X-ray computed tomography apparatus 1 according to the inclusion relationship between the size of the imaging field of view and the contour of the subject S, the subject S and the gantry are not interfered with each other and the subject S is unnecessary. The movement of the gantry body 11 with reduced exposure can be controlled.

(Second Embodiment)
The difference from the first embodiment is that the aperture object detector 42 is not mounted, the non-scan target region and the scan target region are specified based on the imaging range set by the scanogram, and the first embodiment The determination in the embodiment is to execute.

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

  A first upper object detector 161 and a second upper object detector 163 are mounted on the horizontal member 141. Specifically, the first upper object detector 161 and the second upper object detector 163 are on the horizontal member 141 and are symmetrically positioned (line symmetric positions) with the central axis R1 in between. Installed. When the horizontal member 141 is not provided on the gantry device 101, the first upper object detector 161 and the second upper object detector 163 are in a line-symmetric position with respect to the central axis R1. It may be provided on the ceiling of the CT examination room. Note that the number of analyte detectors provided on the horizontal member 141 is not limited to two.

  The first upper object detector 161 outputs to the console 50 the presence / absence of detection of the object, the relative positional relationship of the object with respect to the opening 15, the first upper image obtained by photographing the object, 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 body 11 (the gantry coordinate system) is specified. The first upper object detector 161 may output the presence / absence of detection of the object, the relative positional relationship, the first upper image, and the like to the gantry control circuit 25 and the like.

  The second upper object detector 163 outputs to the console 50 the presence / absence of detection of the object, the relative positional relationship of the object with respect to the opening 15, the second upper image obtained by photographing the object, 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 body 11 (the gantry coordinate system) is specified. The second upper object detector 163 may output the presence / absence of detection of the object, the relative positional relationship, the second upper image, and the like to the gantry control circuit 25 and the like.

  As shown in FIG. 7, the first upper object detector 161 has a detection range B1 in which the position of the object can be detected. The first upper object detector 161 may have a detection range B1 in which a reference position or a reference scale as a reference of the distance between itself and the object can be photographed.

  As shown in FIG. 7, the second upper object detector 163 has a detection range B2 in which the position of the object can be detected. The second upper object detector 163 may have a detection range B2 in which a reference position or a reference scale that is a reference for the distance between itself and the object can be photographed. 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 analyte detector 451 and a second lower analyte detector 453 are provided at symmetrical positions (axisymmetric positions) across the central axis R1. When the mounting table 43 is not provided in the gantry device 101, the first lower object detector 451 and the second lower object detector 453 are in a line-symmetric position with respect to the central axis R1, and It may be provided on the floor of the CT examination room. Note that the number of analyte detectors provided on the mounting table 43 is not limited to two.

  The first lower object detector 451 outputs to the console 50 the presence / absence of detection of the object, the relative positional relationship of the object with respect to the opening 15, the first lower image obtained by photographing the object, and the like. At this time, the relative positional relationship between the position of the subject S (non-scan coordinate data) and the gantry body 11 in the first lower image is specified. The first lower object detector 451 may output the presence / absence of the detection of the object, the relative positional relationship, the first lower image, and the like to the gantry control circuit 25.

  The second upper object detector 163 outputs to the console 50 the presence / absence of detection of the object, the relative positional relationship of the object with respect to the opening 15, the second lower image obtained by photographing the object, and the like. At this time, the relative positional relationship between the position of the subject (non-scan coordinate data) and the gantry body 11 in the second lower image is specified. The second lower object detector 453 may output the presence / absence of detection of the object, 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 object detector 451 has a detection range B3 in which the position of the object can be detected. The first lower object detector 451 may have a detection range B3 in which a reference position or a reference scale that is a reference for the distance between itself and the object can be photographed.

  As shown in FIG. 7, the second lower object detector 453 has a detection range B4 in which the position of the object can be detected. Note that the second lower object detector 453 may have a detection range B4 in which a reference position or a reference scale as a reference of the distance between itself and the object can be photographed. For example, the detection range B3 and the detection range B4 are defined by substantially the same angle.

  The image processing device 53 generates a scanogram based on the data output from the data collection circuit 41 in scanography. The generated scano image is output to the display device 61.

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

  The input device 59 inputs a scano imaging instruction for the subject. The input device 59 inputs a scan range for the displayed scanogram according to an instruction from the operator. For example, the input device 59 determines the scan range by moving two boundary lines according to an instruction to 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 illustrating an example of a 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 region. The margin M corresponds to the difference between the scan range SR and the width Sob 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 scano imaging in response to the input of the scano 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 perform a scan on the scan range set in the scanogram.

  The system control circuit 57 associates the scan range and the gantry coordinate system by aligning the positions with each other. Thereby, the system control circuit 57 can grasp the relative position of the gantry body 11 at the time of scanning with respect to the subject S. The system control circuit 57 determines a 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 an object detector (a first upper object detector 161, a second upper object detector 163, a first lower object detector 451, and a second lower object 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 scanogram do not match (non-match) are represented by non-scan coordinate data (non-scan target region). ). The system control circuit 57 outputs information (scan target coordinate data) regarding the specified scan target area to the determination circuit 63. Note that 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.

  The determination circuit 63 uses the first upper image, the second upper image, the first lower image, and the second lower image before the movement of the gantry body 11 to the scan imaging position (lowering). It is determined whether or not it is placed on 43. The determination circuit 63 includes the first upper image, the second upper image, the first lower image, and the first image while the subject S is placed on the placement table 43 and the gantry body 11 is moved (lowered) to the scano imaging position. Based on the positional relationship between the position of the subject S and the second boundary (interference line) 153 in each of the two lower images, it is determined whether or not the subject S is located in the second region (non-interference region). .

  Specifically, the determination circuit 63 extracts (specifies) 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 non-scan coordinate data exists outside the second region (non-interference region) by comparing the object coordinate data and the second boundary data. That is, the determination circuit 63 performs determination using the coordinates (boundary position information) of the second boundary 153 in the gantry coordinate system and the object coordinate data (object position information).

  The determination circuit 63 compares the object coordinate data and the second boundary data during the arrival of the gantry body 11 at the scano imaging position and during the scano imaging so that the object is outside the second area (non-interference area). It is determined whether or not coordinate data exists.

  Based on the positional relationship between the position of the scan target area specified by the scanogram and the first boundary 151 during the arrival of the gantry body 11 at the scan photographing position and the scan of the scan target area, the determination circuit 63 It is determined whether or not the area is located in the first area (FOV).

  Further, the position information of the subject S (subject coordinate data) acquired by the subject detector and the scanogram are set during the arrival of the gantry body 11 at the scan imaging position and the scan of the scan target region. When the position information of the scan range does not match, that is, when 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 (in the non-interference area). Determine whether or not.

  When it is determined that the subject S placed on the placement table 43 is located in the non-interference area before the gantry body 11 is lowered to the scan imaging position, the gantry control circuit 25 places the gantry at the scan imaging position. In response to an input of an instruction to move the main body 11, the gantry driving device 31 is controlled to lower the gantry main body 11 to the scano imaging position. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the gantry body 11 starts to descend toward the scano imaging position.

  During the movement (lowering) of the gantry body 11 to the scano imaging 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 position of the gantry main body 11 is determined, the gantry control circuit 25 controls the gantry driving device 31 and the like in order to continue the descent of the gantry body 11. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the descent of the gantry body 11 is continued toward the scano imaging position.

  During movement (lowering) of the gantry body 11 to the scan imaging position, a part of the subject S is located outside 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 position is located outside, the gantry control circuit 25 controls the gantry driving device 31 in order to stop the movement of the gantry body 11. The descent of the gantry body 11 is stopped by the control of the gantry control circuit 25 with respect to the gantry driving device 31.

  After stopping the descent of the gantry body 11, it is determined that the non-scan target area is located within the non-interference area, that is, the non-scan coordinate data is located within the non-interference area defined by the second boundary data. In this case, the gantry control circuit 25 controls the gantry driving device 31 in order to move the gantry body 11 to the scan imaging position again in response to the input of the movement resumption instruction via the input device 59. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the gantry body 11 resumes descent toward the scano imaging position.

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

  The non-scan target area is located in the non-interference area during the movement of the gantry body 11 to the scan shooting position after the scan imaging, that is, the non-interference area in which 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, the gantry control circuit 25 controls the gantry driving device 31 and the like in order to continue the movement of the gantry body 11. Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the descent of the gantry body 11 is continued toward the scan imaging position.

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

  After the movement of the gantry body 11 to the scan photographing position is stopped, the non-scan target area is located in the non-interference area, that is, the non-interference area in which the non-scan coordinate data is defined by the second boundary data. If it is determined that the position is located inside, the gantry control circuit 25 controls the gantry driving device 31 to move the gantry body 11 to the scan photographing position again in response to an instruction to resume movement via the input device 59. . Under the control of the gantry control circuit 25 with respect to the gantry driving device 31, the gantry body 11 resumes moving toward the scanning imaging position.

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

  After the processing in step Sb2, the first upper object detector 161 generates a first upper image, and the second upper object detector 163 generates a second upper image. In addition, a first lower image is generated by the first lower object detector 451, and a second lower image is generated by the second lower object detector 453 (step Sb3). 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, object coordinate data is extracted from the upper image and the lower image. Object 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 area, the gantry body 11 is lowered toward the scan imaging position in response to the cradle lowering instruction from the operator via the input device 59 ( Step Sb4).

  If there is subject coordinate data outside the non-interference area 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 body 11 Is stopped (step Sb6). When the object coordinate data is included in the closed curve defined by the boundary data of the second boundary 153 and the descent / restart instruction is input by the operator via the input device 59, the descent of the gantry body 11 is resumed. (Step Sb7).

  If there is no object coordinate data outside the non-interference area in the upper image and the lower image (step Sb5), the gantry body 11 is lowered to the scan imaging position (step Sb8). In response to an operator's scano imaging start instruction via the input device 59, scano imaging is started (step Sb9).

  If the object coordinate data exists outside the non-interference area (step Sb10), that is, if the object coordinate data exists outside the closed curve defined by the boundary data of the second boundary 153, the scan imaging is stopped (step Sb11). The object coordinate data is included in the non-interference area, that is, the object coordinate data is included in the closed curve defined by the boundary data of the second boundary 153, and an instruction to resume scan imaging is given via the input device 59. If input is performed by the operator, scano imaging is resumed (step Sb12).

  If there is no object coordinate data outside the non-interference area (step Sb10), that is, if the object coordinate data is included within the closed curve defined by the boundary data of the second boundary 153, the end of the scan imaging is completed. Scano imaging is performed until instructed (step Sb13).

  When scano shooting is completed, a scano image is generated (step Sb14). A scan range is set using a scanogram in accordance with an operator instruction via the input device 59 (step Sb15). At this time, the position information of the gantry 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 region (non-scan coordinate data) and a scan target region (scan target coordinate data) are set by the upper image and the lower image related to the scan range.

  FIG. 10 is a flowchart illustrating an example of a gantry control process in a scan performed after scano imaging.

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

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

  If the gantry body 11 has not moved to the scan start position, the processes of steps Sc2 to 4 are repeated (step Sc5). If the gantry 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 within the closed curve (FOV) defined by the boundary data of the first boundary 151. If included, scanning is started by an operator's scan 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 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 inside of the closed curve (FOV) defined by the boundary data of the first boundary 151, and scanning is resumed via the input device 59 Is input by the operator, scanning is resumed (step Sc10). If the scan is not resumed, 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 in the closed curve (FOV) defined by the boundary data of the first boundary 151, an instruction to end scanning The scan is executed until there is (step Sc11).

According to the configuration described above, the following effects can be obtained.
According to the X-ray computed tomography apparatus 2 according to the present embodiment, a plurality of sensors (subject detectors) are installed in places other than the gantry body 11, and a scan target region is detected using a scanogram generated by scanography. Based on the boundary position information related to the gantry body 11 and the subject position information, it is determined whether or not the scan target coordinate data is included in the FOV. Scanning can be stopped if the FOV protrudes outside the FOV, and scanning can be resumed by an operator's instruction when the scan target area returns to the FOV. That is, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the relative positional relationship between the gantry body 11 and the subject S is determined based on the scanogram and the output of the subject detector. be able to.

  In addition, according to the X-ray computed tomography apparatus 2 according to the present embodiment, a non-scan target is provided in order to avoid interference with the gantry body 11 without mounting an object detector near the opening 15 of the gantry body 11. When it is determined whether or not the area is out of the interference line, and the non-scan target area is out of the interference line, the vertical movement of the gantry body 11 is stopped, and the non-scan target area is returned in the interference line The vertical movement of the gantry body 11 can be resumed.

  That is, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the height of the gantry body 11 relative to the subject S is determined based on the scanogram and the output from the subject detector. By determining and determining whether or not the area outside the FOV is a scan target area, the scan can be stopped or a predetermined warning can be displayed. Thereby, according to the X-ray computed tomography apparatus 2 according to the present embodiment, the safety of the subject S is ensured, the scan time is not prolonged, and the unnecessary exposure to the subject S is prevented. The area to be scanned can be observed 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 causing the subject S and the gantry body 11 to interfere with each other. .

(Third embodiment)
The difference between the first embodiment and the second embodiment is that the above-described gantry control function is executed in an X-ray computed tomography apparatus that can scan a subject in a prone state. In the following description, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description will be given when necessary. FIG. 13 is a diagram illustrating 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 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 includes a top plate 70 on which the subject S is placed and a bed 71 that supports the top plate 70 so that the top plate 70 can be inserted into the opening 15. The top plate 70 on which the subject S is placed at the time of scanning imaging or scanning imaging is inserted into the opening 15 under the control of the system control circuit 57. The gantry body 11 may move along the Z direction so that the top board 70 on which the subject S is placed is inserted into the opening 15.

  Instead of the upper object detector 16, the rear object detector 73 is provided on the rear (back surface) side of the gantry body 11 via a support column 75 at a position on a substantially extension line of the rotation axis R <b> 3 during non-tilt. It is done. Note that the rear object detector 73 may be provided on the wall surface of the examination room at a position on a substantially extended line of the rotation axis R3 during non-tilt. Instead of the lower object detector 45, the front object detector 77 is provided on the front (front surface) side of the gantry body 11 at a position on a substantially extension line of the rotation axis R3 at the time of non-tilt via a support column 79. It is done. Note that the front object detector 77 may be provided on the wall surface of the examination room at a position on a substantially extended line of the rotation axis R3 during non-tilt. Further, the installation positions of the rear object detector 73 and the front object detector 77 are not limited to positions on the extension line of the rotation axis R3 at the time of non-tilt.

  The rear subject detector 73 and the front subject detector 77 are devices that can detect the subject S from the Z direction parallel to the rotation axis R3 during non-tilt. The rear subject detector 73 and the front subject detector 77 may detect the end of the subject S or may detect the whole body contour of the subject S. The rear object detector 73 and the front object detector 77 are, for example, cameras (movie cameras, video cameras, etc.). The rear subject detector 73 and the front subject detector 77 may have various distance sensors for determining the distance between the subject subject S and the subject S, and the position of the subject S may be determined. You may comprise by the various circuits and optical system regarding the motion capture (motion sensor) to detect.

  The rear subject detector 73 and the front subject detector 77 output to the console 50 the presence / absence of detection of the subject S, 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 a rear image and a front image obtained by photographing the subject S to the console 50, respectively. At this time, the relative positional relationship between the position of the subject S and the gantry body 11 in the rear image and the front image 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 in which the position of the subject S can be detected. Note that the rear object detector 73 and the front object detector 77 have a detection range D1 and a detection range D2 in which a reference position or a reference scale, which is a reference for the distance between the subject object S and the object S, can be photographed. You may have. The reference position or the reference scale is, for example, an object that does not move when the gantry body 11 and the top board 70 are moved relative to each other. The rear object detector 73 and the front object detector 77 may measure the distance from the object S by detecting a reference scale.

(Base control function)
The gantry control function in the present embodiment is the same as that of the first embodiment and the modified example, in that the upper object detector 16 is the rear object detector 73, the lower object detector 45 is the front object detector 77, Since it can be understood by replacing the image with the rear image and the lower image with the front image, the description is omitted. That is, the gantry control mechanism in this embodiment is the same as that described with the X-ray computed tomography apparatuses 1 and 2 in FIGS.

  In the present embodiment, the movement of the top board 70 may be controlled by the system control circuit 57 or the like instead of the movement of the gantry body 11. At this time, the control target is the movement control of the top board 70 instead of the movement control of the gantry body 11 in the first embodiment and the modification. The main memory circuit 55 may store a control mode in which the movement control of the gantry body 11 in the first control mode and the second control mode is replaced with the movement control of the top board 70. The control of the movement of the top plate 70 corresponds to the description in which the movement control of the gantry body 11 is simply replaced with the movement control of the top plate 70, and thus the description thereof is omitted.

According to the configuration described above, in addition to the effects described in the other embodiments and modifications described above, the following effects can be obtained.
According to the X-ray computed tomography apparatus 3 according to the present embodiment, in order to avoid interference with the gantry body 11, it is determined whether or not the non-scan target area is out of the interference line, and the non-scan target area is the interference line. The movement of the top plate 70 can be resumed when the movement of the top plate 70 is stopped and the non-scan target area returns within the interference line. As described above, according to the present embodiment, the X-ray computed tomography apparatus 3 that can reduce unnecessary exposure to the subject S without causing the subject S and the gantry main body 11 to interfere with each other is provided. can do.

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

DESCRIPTION OF SYMBOLS 1, 2 ... X-ray computed tomography apparatus 10, 101 ... Mount apparatus, 11 ... Mount body, 13 ... Support | pillar, 14, 141 ... Horizontal material, 15 ... Opening, 16 ... Upper object detector, 17 ... X X-ray detector, 19 ... X-ray detector, 21 ... rotating frame, 23 ... rotary drive, 25 ... gantry control circuit, 31 ... gantry drive, 39 ... high voltage generator, 41 ... data acquisition circuit (DAS), 42 ... Opening object detector, 43 ... Mounting table, 45 ... Lower object detector, 50 ... Console, 51 ... Image reconstruction device, 53 ... Image processing device, 55 ... Main memory circuit, 57 ... System control circuit, 59 ... Input device 61 ... Display device 63 ... Determining circuit 69 ... Laboratory floor surface 70 ... Top plate 71 ... Bed bed 73 ... Rear object detector 75 ... Post column 77 ... Front object detector 79 ... posts 151 ... first boundary 153 Second boundary (interference line), 155 ... diameter of the first boundary, 157 ... diameter of the second boundary, 161 ... first upper object detector, 163 ... second upper object detector, 451 ... first lower object Specimen detector, 453 ... second lower object detector, 511 ... pre-processing unit, 513 ... projection data storage unit, 515 ... reconstruction calculation unit, A1 ... detection range of upper object detector, A2 ... opening object Detection range of detector, A3... Detection range of lower object detector, B1... Detection range of first upper object detector, B2... Detection range of second upper object detector, B3. Detection range of detector, B4 ... detection range of second lower analyte detector, D1 ... detection range of rear analyte detector, D2 ... detection range of front analyte detector, R1 ... central axis, R2 ... horizontal axis , R3: rotating shaft.

Claims (10)

A gantry having an X-ray tube and an X-ray detector across the opening, and movable relative to the floor of the examination room in order to image the subject by X-rays emitted from the X-ray tube When,
The information for the first boundary indicating the outer edge of the imaging field within the opening and the first boundary between the first boundary and the inner surface of the opening to prevent interference between the subject and the gantry. A storage circuit for storing information relating to two boundaries;
Based on the relative positional relationship between the scan target area of the subject and the first boundary, the X-ray tube is controlled so as to stop X-ray irradiation, or the non-scan target area of the subject A control circuit for controlling the gantry to stop the movement of the gantry based on a relative positional relationship with the second boundary;
An X-ray computed tomography apparatus comprising: The control circuit controls the X-ray tube to stop the X-ray irradiation by the X-ray tube when a part of the scan target region exceeds the first boundary, or the non-scan target region When a part of the frame exceeds the second boundary, the frame is controlled to stop the movement of the frame;
The X-ray computed tomography apparatus according to claim 1. A plurality of analyte detectors for detecting the analyte;
Based on the output from the object detector, it is determined whether or not a part of the scan target area is located outside the first area defined by the first boundary, and is defined by the second boundary. A determination circuit for determining whether or not a part of the non-scan target area is located outside the second area to be
Further comprising
The control circuit controls the gantry based on a determination result by the determination circuit.
The X-ray computed tomography apparatus according to claim 1 or 2. When the control circuit determines that a part of the scan target area is located outside the first area in the scan of the subject, or the non-scan target area outside the second area 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 claim 3. The gantry is a gantry capable of scanning the subject in a standing or sitting position,
The analyte detector is provided on at least one of the upper side and the lower side of the opening and the outer edge of the exterior of the gantry,
The non-scan target region is a region where the subject cannot be detected by the subject detector provided on the outer edge.
The X-ray computed tomography apparatus according to claim 3 or 4. The gantry is a gantry capable of scanning the subject in a standing or sitting position, and performs scanography on the subject.
The analyte detector is provided on an upper side and a lower side of the opening,
The imaging field of view is set using a scanogram obtained by the scano shooting,
The non-scan target region is a region where the scanogram and the subject detected by the subject detector do not match.
The X-ray computed tomography apparatus according to claim 3 or 4. The control circuit performs the scan in response to the scan target area being included in an area defined by the first boundary after the scan is stopped and an input of the scan restart instruction. Control the cradle to resume,
The X-ray computed tomography apparatus according to claim 4. The analyte 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 3 to 7. The subject detector detects an end of the subject or a contour of the subject;
The X-ray computed tomography apparatus according to any one of claims 3 to 8. The memory circuit controls the X-ray tube to stop X-ray irradiation by the X-ray tube when a part of the scan target region exceeds the first boundary, or the non-scan target region A first control mode for controlling the gantry so as to stop the movement of the gantry when a part of the gantry exceeds the second boundary; and when the contour of the subject exceeds the second boundary, the gantry A second control mode for controlling the gantry so as to stop the movement of
The control circuit controls the gantry in the second control mode when the imaging field of view changed by the setting of the operator or the tilt of the gantry with respect to the floor surface is narrower than the contour, and the setting by the operator or the 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.
The X-ray computed tomography apparatus according to any one of claims 1 to 9.