JP2022039436A - X-ray ct apparatus, control method of the x-ray ct apparatus and program - Google Patents

Abstract

To expand a region that can be imaged while suppressing reduction in the image quality of a reconstruction image.SOLUTION: An X-ray CT apparatus according to an embodiment comprises: an X-ray tube; an X-ray detector; a rotation unit; a drive device; and a drive control unit. The X-ray tube emits the X-ray while rotating. The X-ray detector detects the X-ray emitted from the X-ray tube. The rotation unit rotates the X-ray tube and the X-ray detector around the rotation center of the X-ray tube. The drive device exists in the rotation unit and moves one or both of the X-ray tube and the X-ray detector. The drive control unit causes the drive device to move one or both of the X-ray tube and the X-ray detector in the direction intersecting the diameter direction of the rotation in a prescribed case.SELECTED DRAWING: Figure 1

Description

The embodiments disclosed in the present specification and the drawings relate to an X-ray CT apparatus, a control method of the X-ray CT apparatus, and a program.

Conventionally, an X-ray CT (Computed Tomography) device that reconstructs captured data while rotating a pair of an X-ray tube and an X-ray detector at high speed around a subject to generate a tomographic image of the subject has been known. ing. Further, in order to widen the area that can be imaged without increasing the number of X-ray detection elements constituting the X-ray detector, an X-ray CT apparatus that performs data correction or performs imaging using an asymmetric detector is known. ing. The asymmetry detector is an X-ray detector arranged so that the X-ray detector is asymmetric with respect to the channel direction about an extension line passing through the focal point of the X-ray tube and the rotation center of the gantry. It is a detector. In an X-ray CT device that uses an asymmetric detector, the area that can be imaged by rotating the gantry and performing a full scan is targeted by the X-ray detector up to the outermost channel of the asymmetric detector. It can be expanded to the same area as when using the X-ray detector. Even in the case of an asymmetric detector, image quality correction processing is required due to the relationship between the position and angle of the X-ray detection element and the X-ray tube.

However, when data correction is performed to widen the area that can be imaged, the image quality may be deteriorated as compared with the case where the correction is not performed. Further, when the asymmetric detector is used, since the X-ray detector and the X-ray tube are fixed at the asymmetric position in advance, the expanded area is also fixed.

Japanese Unexamined Patent Publication No. 2018-114211 International Publication No. 2013/161443 Japanese Unexamined Patent Publication No. 2010-46102

One of the problems to be solved by the embodiments disclosed in the present specification and the drawings is to expand the imagelable area while suppressing the deterioration of the image quality of the reconstructed image. However, the problems to be solved by the embodiments disclosed in the present specification and the drawings are not limited to the above problems. The problem corresponding to each effect by each configuration shown in the embodiment described later can be positioned as another problem.

The X-ray CT apparatus of the embodiment includes an X-ray tube, an X-ray detector, a rotating unit, a drive device, and a drive control unit. The X-ray tube irradiates X-rays while rotating. The X-ray detector detects the X-rays emitted from the X-ray tube. The rotating unit rotates the X-ray tube and the X-ray detector around the rotation center of the X-ray tube. The drive device exists in the rotating part and moves one or both of the X-ray tube and the X-ray detector. In a predetermined case, the drive control unit causes the drive device to move one or both of the X-ray tube and the X-ray detector in a direction intersecting the radial direction of the rotation.

The figure which shows one configuration example of the X-ray CT apparatus 1 in 1st Embodiment. The figure which shows one configuration example of a position control function 51. The figure for demonstrating the image acquisition function 51-1. The figure for demonstrating the content of the movement amount information 41-1. The figure for demonstrating that the X-ray detector moves 15 by the control of a drive control function 51-5. The figure for demonstrating rotating an X-ray tube 11. The figure for demonstrating moving an X-ray tube 11. The figure for demonstrating the moving direction when the shape of an X-ray detector is a plane detector. The figure for demonstrating the moving direction of the X-ray detector 15 #. The figure for demonstrating the generation process of the reconstructed image in 1st Embodiment. The figure which shows an example of the generated reconstructed image. The flowchart which shows an example of the flow of the process executed by the X-ray CT apparatus in 1st Embodiment. The flowchart which shows an example of the flow of the process executed by the X-ray CT apparatus in 2nd Embodiment. The figure which shows one configuration example of the X-ray CT apparatus 2 in 3rd Embodiment. The flowchart which shows an example of the flow of the process executed by the X-ray CT apparatus in 3rd Embodiment. The figure which shows one configuration example of the X-ray CT apparatus 3 in 4th Embodiment. The flowchart which shows an example of the flow of the process executed by the X-ray CT apparatus 3 in 4th Embodiment. The flowchart which shows an example of the flow of the process executed by the X-ray CT apparatus in 5th Embodiment.

Hereinafter, the X-ray CT apparatus, the control method of the X-ray CT apparatus, and the program of the embodiment will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a diagram showing a configuration example of the X-ray CT apparatus 1 according to the first embodiment. The X-ray CT device 1 includes, for example, a gantry device 10, a sleeper device 30, and a console device 40. The gantry device 10 includes, for example, an X-ray tube 11, a wedge 12, a collimator 13, an X-ray high voltage device 14, an X-ray detector 15, and a data acquisition system (hereinafter, DAS: Data Acquisition System) 16. , A rotating frame 17, and a control device 18. The rotating frame 17 is an example of a “rotating portion”. The control device 18 is an example of a “control unit”.

The X-ray tube 11 generates X-rays by irradiating thermoelectrons from the cathode (filament) toward the anode (target) by applying a high voltage from the X-ray high voltage device 14. The X-ray tube 11 includes a vacuum tube. For example, the X-ray tube 11 is a rotating anode type X-ray tube that generates X-rays by irradiating a rotating anode with thermions. The X-ray tube 11 irradiates X-rays while rotating around the rotation center of the X-ray tube 11. The X-ray tube 11 may be equipped with a first drive device 11A capable of moving the position of the X-ray tube 11 in a predetermined direction from a reference position described later. The first drive device 11A may rotate the irradiation axis passing through the focal point of the X-ray tube 11 from the center of the X-ray tube 11 by a predetermined angle from the reference axis (-Y-axis direction in the figure). Further, the first drive device 11A may move not only the X-ray tube 11 but also the wedge 12 in the above-mentioned predetermined direction or a predetermined angle.

The wedge 12 is a filter for adjusting the X-ray dose applied to the subject P from the X-ray tube 11. The wedge 12 attenuates the X-rays passing through itself so that the distribution of the X-ray dose applied to the subject P from the X-ray tube 11 becomes a predetermined distribution. The wedge 12 is also called a wedge filter or a bow-tie filter. The wedge 12 is made by processing aluminum so as to have a predetermined target angle and a predetermined thickness, for example.

The collimator 13 is a mechanism for narrowing the irradiation range of X-rays transmitted through the wedge 12. The collimator 13 narrows down the X-ray irradiation range by forming a slit, for example, by combining a plurality of lead plates. The collimator 13 may be called an X-ray diaphragm. The collimator 13 narrows down X-rays to the shape of a quadrangular pyramid, for example. Of the spread angles of the X-rays, the spread angle along the rotation direction of the rotating frame 17 is referred to as a fan angle, and the spread angle in a direction orthogonal to the fan angle is referred to as a cone angle. The collimator 13 may be equipped with a second drive device 13A capable of dynamically changing the irradiation range of the X-ray to be narrowed down. A combination of the collimator 13 and the second drive device 13A may be referred to as a "collimator device".

The X-ray high voltage device 14 includes, for example, a high voltage generator and an X-ray control device. The high voltage generator has an electric circuit including a transformer, a rectifier, and the like, and generates a high voltage applied to the X-ray tube 11. The X-ray control device controls the output voltage of the high voltage generator according to the X-ray dose to be generated in the X-ray tube 11. The high voltage generator may be one that boosts the voltage by the transformer described above, or may be one that boosts the voltage by an inverter.
The X-ray high voltage device 14 may be provided on the rotating frame 17 or may be provided on the side of the fixed frame (not shown) of the gantry device 10.

The X-ray detector 15 detects the intensity of X-rays generated by the X-ray tube 11 and passed through the subject P to be incident. The X-ray detector 15 outputs an electric signal (which may be an optical signal or the like) according to the intensity of the detected X-ray to the DAS 18. The X-ray detector 15 has, for example, a plurality of X-ray detection element trains. In the example of FIG. 1, the X-ray detector 15 is formed in an arc shape centered on the focal point of the X-ray tube 11. In each of the plurality of X-ray detection element trains, a plurality of X-ray detection elements are arranged in the channel direction along the arc. The X-ray detector 15 has a structure in which, for example, a plurality of detection element trains in which a plurality of detection elements are arranged in the channel direction are arranged in a row direction (slice direction, row direction).

The X-ray detector 15 is an indirect detector having, for example, a grid, a scintillator array, and an optical sensor array. The scintillator array has a plurality of scintillators. Each scintillator has a scintillator crystal. The scintillator crystal emits light in an amount corresponding to the intensity of incident X-rays. The grid is arranged on the plane on which the X-rays of the scintillator array are incident and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may also be called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array has, for example, an optical sensor such as a photomultiplier tube (PMT). The optical sensor array outputs an electric signal according to the amount of light emitted by the scintillator. The X-ray detector 15 may be a direct conversion type detector having a semiconductor element that converts incident X-rays into an electric signal. An optical sensor or a semiconductor element is an example of a "detection element".

Further, the X-ray detector 15 may be equipped with a third drive device 15A capable of moving the position of the X-ray detector 15 in a predetermined direction from the reference position. Here, the reference positions of the X-ray tube 11 and the X-ray detector 15 are, for example, the X-ray detection elements arranged in the X-ray detector 15 on the irradiation axis of the X-ray tube 11 with respect to the channel direction. It is a position that is positioned so as to be symmetrical. The X-ray tube 11 and the X-ray detector 15 can be operated as a symmetry detector when they are present at the reference position. Further, the third drive device 15A may move not only the X-ray detector 15 but also the DAS 16 in a predetermined direction. The first drive device 11A and the third drive device 15A described above move one or both of the X-ray tube 11 and the X-ray detector 15. The above-mentioned first drive device 11A, second drive device 13A, and third drive device 15A may be provided as one drive device.

The DAS 16 has, for example, an amplifier, an integrator, and an A / D converter. The amplifier performs amplification processing on the electric signal output by each X-ray detection element of the X-ray detector 15. The integrator integrates the amplified electrical signal over the view period (discussed below). The A / D converter converts an electric signal indicating the integration result into a digital signal. The DAS 16 outputs the detection data based on the digital signal to the console device 40. The detection data is a digital value of the X-ray intensity identified by the channel number, the column number, and the view number indicating the collected view of the X-ray detection element of the generation source. The view number is a number that changes according to the rotation of the rotation frame 17, and is, for example, a number that is incremented according to the rotation of the rotation frame 17. Therefore, the view number is information indicating the rotation angle of the X-ray tube 11. The view period is a period within the period from the rotation angle corresponding to a certain view number to the arrival of the rotation angle corresponding to the next view number. The DAS 16 may detect the change of view by a timing signal input from the control device 18, an internal timer, or a signal acquired from a sensor (not shown). .. For example, when X-rays are continuously exposed by the X-ray tube 11 in the case of performing a full scan, the DAS 16 collects, for example, a detection data group for the entire circumference (360 degrees). When X-rays are continuously exposed by the X-ray tube 11 in the case of performing a half scan, the DAS 16 collects detection data for a half circumference (180 degrees).

The rotating frame 17 is an annular rotating member that rotates the X-ray tube 11, the wedge 12, the collimator 13, and the X-ray detector 15 in a state of facing each other. The rotating frame 17 includes, for example, a rotating support portion that rotates an X-ray tube 11, a wedge 12, a collimator 13, and an X-ray detector 15 around the center of rotation of the X-ray tube 11, a rotating support portion, and X-rays. It includes a tube 11, a wedge 12, a collimator 13, an X-ray detector 15, a first drive 11A, a second drive 13A, and a gantry (eg, a gantry 10) that houses a third drive 15A. For example, the subject P is present at the center of rotation. The rotating frame 17 further supports the DAS 16. The detection data output by the DAS 16 has a photodiode provided in a non-rotating portion (for example, a fixed frame) of the gantry device 10 by optical communication from a transmitter having a light emitting diode (LED) provided in the rotating frame 17. It is transmitted to the receiver and transferred to the console device 40 by the receiver. The method of transmitting the detection data from the rotating frame 17 to the non-rotating portion is not limited to the above-mentioned method using optical communication, and any non-contact type transmitting method may be adopted. The rotating frame 17 is not limited to an annular member but may be a member such as an arm as long as it can support and rotate the X-ray tube 11 and the X-ray detector 15.

The control device 18 has, for example, a processing circuit having a processor such as a CPU (Central Processing Unit) and a drive mechanism including a motor, an actuator, and the like. The control device 18 receives an input signal from the input interface 43 attached to the console device 40 or the gantry device 10, and controls the operation of each device such as the gantry device 10 and the sleeper device 30.

The control device 18 rotates, for example, the rotating frame 17, tilts the gantry device 10, and moves the top plate 33 of the sleeper device 30. When tilting the gantry device 10, the control device 18 rotates the rotating frame 17 around an axis parallel to the Z-axis direction based on the tilt angle (tilt angle) input to the input interface 43. The control device 18 grasps the rotation angle of the rotation frame 17 by the output of a sensor (not shown) or the like. Further, the control device 18 provides the processing circuit 50 with the rotation angle of the rotation frame 17 at any time. The control device 18 may be provided in the gantry device 10 or in the console device 40.

The control device 18 obtains a first image of the first range of the subject P by, for example, taking an image in a state where one or both of the X-ray tube 11 and the X-ray detector 15 are arranged in the first position. The first control to obtain is performed. Further, the control device 18 performs imaging with one or both of the X-ray tube 11 and the X-ray detector 15 in the second arrangement, so that the second range is different from the first range of the subject P. A second control is performed to obtain a second image of the range. For example, as the first control, the control device 18 arranges the X-ray tube 11 and the X-ray detector 15 in the first arrangement prior to the main scan imaging, performs scanno imaging for positioning, and performs the first scano imaging. Acquire a scanno image (first image) of the range. For example, in the control device 18, as a second control, the X-ray tube 11 and the X-ray detector 15 are arranged in the second position, the gantry device 10 is self-propelled along the moving rail, and is irradiated from the X-ray tube 11. The main scan image of the subject P in the second range is taken by the X-ray, and the target main scan image (second image) is acquired. The control described above is executed by the control from the processing circuit 50.

The sleeper device 30 is a device on which the subject P to be scanned is placed and introduced into the rotating frame 17 of the gantry device 10. The sleeper device 30 has, for example, a base 31, a sleeper drive device 32, a top plate 33, and a support frame 34. The base 31 includes a housing that movably supports the support frame 34 in the vertical direction (Y-axis direction). The sleeper drive device 32 includes a motor and an actuator. The sleeper drive device 32 moves the top plate 33 on which the subject P is placed along the support frame 34 in the longitudinal direction (Z-axis direction) of the top plate 33. The top plate 33 is a plate-shaped member on which the subject P is placed.

The console device 40 has, for example, a memory 41, a display 42, an input interface 43, a network connection circuit 44, and a processing circuit 50. In the first embodiment, the console device 40 will be described as a separate body from the gantry device 10, but the gantry device 10 may include a part or all of each component of the console device 40.

The memory 41 is realized by, for example, a RAM (Random Access Memory), a semiconductor memory element such as a flash memory, a hard disk, an optical disk, or the like. The memory 41 stores, for example, movement amount information 41-1 and the like. The movement amount information 41-1 is, for example, information in which the movement amount of the X-ray tube 11 and the X-ray detector 15 is associated with the imaging conditions and the subject information. Further, in the movement amount information 41-1, in addition to the movement amount of the X-ray tube 11 and the X-ray detector 15, the movement amount of the collimator 13 (for example, the movement amount for changing the irradiation range of the X-ray to be narrowed down). May be associated with each other. The contents of the movement amount information 41-1 will be described later. Further, the memory 41 may store, for example, detection data, projection data, reconstructed image, CT image, etc. acquired by the X-ray CT apparatus 1. These data may be stored in an external memory with which the X-ray CT apparatus 1 can communicate, instead of the memory 41 (or in addition to the memory 41). The external memory is controlled by the cloud server, for example, when the cloud server that manages the external memory receives a read / write request from the console device 40.

The display 42 displays various information. For example, the display 42 uses a medical image (for example, a CT image) generated by the processing state of the X-ray CT apparatus 1 or a processing circuit, a GUI (Graphical User Interface) image that accepts various operations by an operator, and an input interface 43. Display the received information, etc. The display 42 is, for example, a liquid crystal display, a CRT (Cathode Ray Tube), an organic EL (Electroluminescence) display, or the like. The display 42 may be provided on the gantry device 10. The display 42 may be a desktop type or a display device (for example, a tablet terminal) capable of wirelessly communicating with the main body of the console device 40.

The input interface 43 receives various input operations by the operator and outputs an electric signal indicating the contents of the received input operations to the processing circuit 50. For example, the input interface 43 accepts information input operations such as shooting conditions, execution of scan shooting, and image display request. The imaging conditions include, for example, information on the distance from the X-ray tube 11 to the X-ray detector 15, the position of the channel of the X-ray detector 15, and the number of information. The imaging conditions include, for example, a scan plan, a collection condition when collecting detection data or projection data, a reconstruction condition when reconstructing a CT image, and image processing when generating a post-processed image from a CT image. Conditions and the like may be included. The scan plan includes, for example, a portion to be imaged of the reconstructed image, an X-ray irradiation amount, an irradiation timing, an imaging time, a type of scanning, and the like. As for the above-mentioned shooting conditions, a plurality of types of conditions may be set in advance as operation modes. In that case, the shooting conditions are determined by selecting one of a plurality of types of operation modes by the input interface 43.

The input interface 43 is realized by, for example, a mouse, a keyboard, a touch panel, a drag ball, a switch, a button, a joystick, a foot pedal, a camera, an infrared sensor, a microphone, and the like. The input interface 43 may be provided on the gantry device 10. Further, the input interface 43 may be realized by a display device (for example, a tablet terminal) capable of wireless communication with the main body of the console device 40. In the present specification, the input interface 43 is not limited to the one provided with physical operating parts such as a mouse and a keyboard. For example, an example of an input interface includes an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the device and outputs the electric signal to a control circuit.

The network connection circuit 44 implements various information and communication protocols according to the form of the network. The network connection circuit 44 connects the X-ray CT device 1 and other devices according to the various protocols. An electrical connection or the like via an electronic network can be applied to this connection. Here, the electronic network means a general information communication network using telecommunications technology, and includes LAN (Local Area Network), WAN (Wide Area Network), Internet network, telephone communication line network, optical fiber communication network, and so on. Cable communication networks, satellite communication networks, etc. are included.

The processing circuit 50 controls the overall operation of the X-ray CT apparatus 1. The processing circuit 50 executes, for example, a position control function 51, a system control function 52, a preprocessing function 53, a reconstruction processing function 54, an image processing function 55, a scan control function 56, a display control function 57, and the like. The processing circuit 50 realizes these functions, for example, by the hardware processor executing a program stored in the memory 41.

The hardware processor is, for example, a CPU, a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), a programmable logic device (for example, a simple programmable logic device (SPLD)) or It means a circuit (circuitry) such as a complex programmable logic device (CPLD) or a field programmable gate array (FPGA). Instead of storing the program in the memory 41, the program may be configured to be directly embedded in the circuit of the hardware processor. In this case, the hardware processor realizes the function by reading and executing the program embedded in the circuit. The hardware processor is not limited to the one configured as a single circuit, but may be configured as one hardware processor by combining a plurality of independent circuits to realize each function. Further, the processing circuit 50 may integrate a plurality of components into one hardware processor to realize each function.

Each component of the console device 40 or the processing circuit 50 may be decentralized and realized by a plurality of hardware. The processing circuit 50 may be realized not by the configuration of the console device 40 but by a processing device capable of communicating with the console device 40. The processing device is connected to, for example, a workstation connected to one X-ray CT device or a plurality of X-ray CT devices, and collectively executes the same processing as the processing circuit 50 described below (for example,). , Cloud server).

The position control function 51 moves one or both of the X-ray tube 11 and the X-ray detector 15 in a predetermined direction or a predetermined angle in a predetermined case. The predetermined case is, for example, a case where one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved. The details of the position control function 51 will be described later.

The system control function 52 controls various functions of the processing circuit 50 based on the input operation received by the input interface 43. For example, the system control function 52 controls, for example, the X-ray high voltage device 14, the DAS 16, the control device 18, and the sleeper drive device 32 to execute the collection process of the detection data in the gantry device 10. Further, the system control function 52 controls the operation of each part when the scanno image by the scanno shooting, the shooting for collecting the main scan image by the main scan shooting, and the reconstructed image used for the diagnosis are shot.

The preprocessing function 53 performs preprocessing such as logarithmic conversion processing, offset correction processing, sensitivity correction processing between channels, and beam hardening correction on the detection data output by DAS16 to generate projection data. The projected projection data is stored in the memory 41.

The reconstruction processing function 54 generates a reconstruction image (CT image) by performing reconstruction processing on the projection data generated by the preprocessing function 53 by a filter correction back projection method, a successive approximation reconstruction method, or the like. do. Further, the reconstruction processing function 54 may store the generated CT image in the memory 41.

The image processing function 55 converts a CT image into a three-dimensional image or cross-sectional image data of an arbitrary cross section by a known method based on the input operation received by the input interface 43. The conversion to a three-dimensional image may be performed by the preprocessing function 53. Further, the image processing function 55 may analyze the image of the cross-sectional image data and classify the shape (body shape) and size (size) of the subject based on the analysis result.

The scan control function 56 controls the collection process of the detection data in the gantry device 10 by instructing the X-ray high voltage device 14, the DAS 16, the control device 18, and the sleeper drive device 32. The scan control function 56 controls, for example, the operation of each part when shooting a scanno image or a main scan image, and shooting an image used for diagnosis.

The display control function 57 displays the operating status of the X-ray CT apparatus 1 and various images (photographed images, images showing the input operation results accepted by the input interface 43, etc.) on the display 42. For example, the image showing the input operation result includes, for example, the shape and size of the subject P received by the input interface 43, the imaging conditions, the amount of movement of the X-ray tube 11 or the X-ray detector 15, and the X-rays after movement. Images showing the location of the tube 11 and the X-ray detector 15 are included.

With the above configuration, the X-ray CT apparatus 1 performs the main scan imaging of the subject P in a format such as a helical scan or a step-and-shoot scan. The helical scan is a mode in which the rotating frame 17 is rotated while the top plate 33 is moved to scan the subject P in a spiral shape. The step-and-shoot scan is an embodiment in which the position of the top plate 33 is moved at regular intervals to perform a conventional scan in a plurality of scan areas. The format (type of shooting) for shooting is set to the shooting conditions accepted by the input interface 43. In the following, it will be described that the scan image of the subject P is performed by the helical scan.

Next, the details of the position control function 51 will be described. FIG. 2 is a diagram showing a configuration example of the position control function 51. The position control function 51 includes, for example, an image acquisition function 51-1, a subject information acquisition function 51-2, an imaging range determination function 51-3, a movement necessity determination function 51-4, and a drive control function 51-. 5 and. A combination of the image acquisition function 51-1 and the subject information acquisition function 51-2 is an example of the “acquisition unit”. The shooting range determination function 51-3 is an example of the “shooting range determination unit”. The drive control function 51-5 is an example of a “drive control unit”.

In the first embodiment, the image acquisition function 51-1 acquires a scanno image prior to the execution of the main scan shooting. FIG. 3 is a diagram for explaining the image acquisition function 51-1. In the example of FIG. 3, the configuration mounted on the rotating frame 17 is mainly shown, and some reference numerals and configurations are omitted. Specifically, FIG. 3 shows an X-ray tube 11, a wedge 12, a collimator 13, an X-ray detector 15, a DAS 16, a rotating frame 17, a first drive device 11A, and a second drive device. 13A and the third drive device 15A are shown. The broken line BL indicates the outer edge of the fan angle. In the example of FIG. 3, for convenience of explanation, two subjects P1 and P2 are shown, but one subject is placed on the top plate 33.

At the time of scanno imaging in the first embodiment, the X-ray tube 11 and the X-ray detector 15 are positioned at a reference position (an example of the first arrangement) as shown in FIG. In this case, the X-ray detector 15 exists at a position facing the X-ray tube 11, and specifically, the X-ray detector 15 is orthogonal to the body axes and the X-ray irradiation axes of the subjects P1 and P2. It exists in the direction. Further, the X-ray detector 15 is positioned so that the center C2 of the X-ray detector 15 exists on the irradiation axis which is the central axis of the irradiation range of the X-rays emitted from the X-ray tube 11. In the example of FIG. 3, the center C1 of the irradiation port of the X-ray tube and the rotation center C0 of the X-ray tube 11 are positioned on the irradiation axis. When positioned at the reference position, the detection range of the detection data by the X-ray detector 15 is point symmetry with respect to the center CL2 of the X-ray detector 15 or axis symmetry with reference to the X-ray irradiation axis. Further, the reference position has a detection surface symmetrical in the channel direction with respect to the center line passing through the focal point of the X-ray tube 11 and the rotation axis of the gantry device 10. That is, the reference position means that the X-ray tube 11 and the X-ray detector 15 are positioned symmetrically as shown in FIG.

The image acquisition function 51-1 controls the control device 18 to cause the system control function 52 and the scan control function 56 to execute control for scanno imaging prior to the execution of the main scan capture, and the captured scanno image is captured. (First image) is acquired. Scannographing is performed, for example, without rotating the rotating frame 17 that supports the X-ray tube 11 and the X-ray detector 15. Further, the scanno imaging may be performed by irradiating the subject P on the sleeper device 30 with X-rays from two predetermined directions such as the front direction and the side direction. In this way, the scanno image is taken by the one-way or two-way scanno shooting.

The subject information acquisition function 51-2 acquires information on the shape and size of the subject P based on the scanno image acquired by the image acquisition function 51-1. Further, the subject information acquisition function 51-2 is, for example, information on the shape and size of the subject P received by the input interface 43, information on the imaging target range (the imaging range of the reconstructed image), and information on the imaging conditions. Etc. may be obtained.

The shooting range determination function 51-3 has a shooting range (for example, when the main scan shooting is performed at the reference positions of the X-ray tube 11 and the X-ray detector 15 based on the scanno image acquired by the image acquisition function 51-1. , FOV; Field of View). For example, the shooting range determination function 51-3 performs image analysis for extracting features from a scanno image. Further, the imaging range determination function 51-3 is a region of the subject P included in the scanno image by using the feature information obtained by image analysis and a technique such as pattern matching using a template of a portion prepared in advance. And the location of the site (eg, head, chest, arms, abdomen) may be acquired. In this case, the imaging range determination function 51-3 determines a portion included in the imaging range.

Further, the imaging range determination function 51-3 may set the imaging range based on the imaging range of the user (for example, the operator of the X-ray CT apparatus) accepted by the input interface 43. In this case, the shooting range determination function 51-3 accepts and accepts an input of any one of a plurality of predetermined FOV sizes (for example, S, M, L, LL, XL) from the input interface 43. The shooting range associated with the assigned FOV size is determined.

The movement necessity determination function 51-4 determines whether or not one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved. For example, the movement necessity determination function 51-4 moves one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position based on the imaging range determined by the imaging range determination function 51-3. Determine if it is necessary. For example, in the case of the subject P1 shown in FIG. 3, the width of the subject P1 on the left and right (in the X-axis direction in the figure) is included in the outer edge line of the fan angle. Therefore, even if the imaging target portion is the body of the subject P1, it is included in the imaging range. In this case, the movement necessity determination function 51-4 determines that it is not necessary to move one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position.

On the other hand, in the case of the subject P2, a part of the subject P1 (in the example of FIG. 3, the left and right sides (both arm portions) of the subject P1) exceeds the range of the fan angle. Therefore, the movement necessity determination function 51-4 may be used in one of the X-ray tube 11 and the X-ray detector 15 or when the imaging target portion is the arm portion (when a reconstructed image of the arm portion is required). It is determined that both need to be moved from the reference position. The head of the subject P2 is included in the outer edge of the fan angle at the reference position. Therefore, the movement necessity determination function 51-4 needs to move one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position when the imaging target range is the head of the subject P2. It is determined that there is no such thing. In this way, it is possible to more appropriately determine whether or not to move from the reference position depending on the size of the subject, the object to be imaged, and the range to be photographed.

As an example of a predetermined case, the drive control function 51-5 determines that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved by the movement necessity determination function 51-4. In addition, one or both of the X-ray tube 11 and the X-ray detector 15 are moved by the drive device (first drive device 11A, third drive device 15A). For example, when the drive control function 51-5 determines that it is necessary to move one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position by the movement necessity determination function 51-4, The amount of movement of one or both of the X-ray tube 11 and the X-ray detector 15 is determined. For example, the movement amount information 41-1 is referred to based on the shooting conditions of the image acquired by the image acquisition function 51-1, the analysis result of the image, and the subject information acquired by the subject information acquisition function 51-2. , The movement amount of one or both of the X-ray tube 11 and the X-ray detector 15 is acquired.

FIG. 4 is a diagram for explaining the contents of the movement amount information 41-1. The movement amount information 41-1 is, for example, information in which the X-ray detector movement amount, the X-ray tube movement amount, and the collimator movement amount are associated with the imaging conditions and the subject information. The imaging conditions (for example, imaging conditions SC1 to SC4 shown in FIG. 4) include, for example, the distance from the X-ray tube 11 to the X-ray detector 15 at the reference position, the position, number, and arrangement of the channels of the X-ray detector 15. The state is included. The imaging conditions are information determined before the operation of the X-ray CT apparatus 1, but may be changed depending on the information received by the input interface 43. In addition, the shooting conditions may include information regarding the operation mode at the time of shooting. The subject information includes, for example, information regarding the shape and size of the subject and information regarding the imaging target site. The X-ray detector movement amount (for example, the movement amounts M1 to M3 shown in FIG. 4) includes the movement amount of the X-ray detector 15 from the reference position. The X-ray tube movement amount (for example, the movement amounts M4 to M5 shown in FIG. 4) includes the movement amount of the X-ray tube 11 from the reference position and the rotation angle from the reference angle. The collimator movement amount (for example, movement amounts M6 to M9 shown in FIG. 4) includes, for example, an X-ray detector whose irradiation range from the X-ray tube 11 is based on the movement of the X-ray detector 15 and the X-ray tube 11. Includes the amount of movement of the collimator 13 for adjusting to illuminate the area where 15 is present. The X-ray detector movement amount and the X-ray tube movement amount are, for example, the minimum movement amounts for including the shooting target range in the shooting range of the main scan shooting. The X-ray detector movement amount and the X-ray tube movement amount are the movement amounts at which one end of the left and right ends of the subject P placed on the top plate 33 is estimated to be included in the scanning range of the scanno image. There may be. By moving the X-ray tube 11 or the X-ray detector 15, the X-ray tube 11 and the X-ray detector 15 are positioned at asymmetric positions.

When it is determined by the movement necessity determination function 51-4 that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved, the drive control function 51-5 may be subject to imaging conditions or a subject. Using the sample information, refer to the imaging conditions and subject information of the movement amount information 41-1, and the X-ray detector movement amount, X-ray tube movement amount, and X-ray tube movement amount associated with the matching imaging conditions and subject information. Acquire the amount of movement of the collimator. The drive control function 51-5 uses a predetermined function to move the X-ray detector, the X-ray tube, and the collimator instead of referring to the movement amount information 41-1. The amount may be calculated. The predetermined function includes, for example, each function that outputs an X-ray detector movement amount, an X-ray tube movement amount, or a collimator movement amount by inputting imaging conditions and subject information. Further, the function for outputting the collimator movement amount may be a function for outputting the collimator movement amount by inputting the X-ray detector movement amount and the X-ray tube movement amount instead of the imaging conditions and the subject information.

The drive control function 51-5 controls the drive devices (first drive device 11A, second drive device 13A, third drive device 15A) based on the acquired movement amount, and controls the X-ray tube 11, the collimator 13, and the collimator 13. The X-ray detector 15 is moved from the reference position. For example, the first drive device 11A and the third drive device 15A intersect one or both of the X-ray tube 11 and the X-ray detector 15 with the radial direction of rotation about the center of rotation of the X-ray tube 11. Move in the direction. Further, based on the above movement, the second drive device 13A moves the collimator 13 so that the X-rays emitted by the X-ray tube 11 are irradiated in the range where the X-ray detector 15 exists.

FIG. 5 is a diagram for explaining that the X-ray detector moves 15 under the control of the drive control function 51-5. In the example of FIG. 5, the subject P2 is placed on the top plate 33. Further, the example of FIG. 5 is a diagram illustrating the movement of the X-ray detector 15 in order to include the body (entire width) of the subject P2 in the imaging range. FIG. 5 shows an example in which the X-ray detector 15 is moved from the reference position by the distance D1 in the rotation direction of the rotation frame 17 and in the channel arrangement direction as a second arrangement as compared with FIG. Shows. The arrangement direction of the channels may be rephrased as, for example, the direction along the circumference in which the X-ray detector 15 is rotated by the rotation frame 17.

The drive control function 51-5 outputs control information to the third drive device 15A so as to move the X-ray detector 15 based on the amount of movement of the X-ray detector. The third drive device 15A drives a motor, an actuator, or the like based on the control information to move the X-ray detector 15 to the position of the distance D1. That is, the third drive device 15A moves the X-ray detector 15 to move the X-ray tube 11, the rotation center C0 of the X-ray tube 11, and the center C2 in the circumferential direction of the X-ray detector 15 during rotation. And should not be on the same straight line. The state in which the X-ray tube 11 and the X-ray detector 15 are not on the same straight line is a state in which the X-ray tube 11 and the X-ray detector 15 are in an asymmetrical position. Further, the drive control function 51-5 outputs control information to the second drive device 13A so as to move the collimator 13 based on the collimator movement amount. The second drive device 13A drives the motor, actuator, or the like based on the control information, and the collimator 13 so that the irradiation range of the X-rays emitted from the X-ray tube 11 is included in the detection range of the X-ray detector 15. To adjust the fan angle. In the example of FIG. 5, by moving the X-ray detector 15 from the reference position to the right side, the X-ray detector 15 is moved to a position where the entire right side of the subject P2 is included in the imaging range as the second imaging range.

Further, the drive control function 51-5 may rotate the irradiation axis of the X-ray tube 11 by a predetermined angle based on the movement of the X-ray detector 15. FIG. 6 is a diagram for explaining rotating the X-ray tube 11. In the example of FIG. 6, the drive control function 51-5 is based on the movement amount of the X-ray detector 15 so that the irradiation axis of the X-ray tube 11 passes through the center C2 of the X-ray detector 15. Control information is output to the first drive device 11A so that the irradiation axis of 11 is rotated from the reference axis (-Y-axis direction in the figure) to the angle θ1. The rotation angle θ1 may be included in the amount of movement of the X-ray tube. As a result, the scan can be executed while maintaining the relative positions of the X-ray tube 11 and the X-ray detector 15 before and after the movement of the X-ray detector 15.

FIG. 7 is a diagram for explaining moving the X-ray tube 11. The drive control function 51-5 outputs control information to the first drive device 11A so as to move the X-ray tube 11 based on the amount of movement of the X-ray tube. The first drive device 11A drives a motor, an actuator, or the like based on the control information to move the X-ray tube 11 to the position of the distance D2 shown in FIG. That is, the first drive device 11A moves the X-ray tube 11 to the X-ray tube 11, the rotation center C0 of the X-ray tube 11, and the center C2 in the circumferential direction of the X-ray detector 15 during rotation. However, it is set to a state where it is not on the same straight line (second arrangement state). In the example of FIG. 7, the X-ray tube 11 is moved horizontally in the X-axis direction in the figure, but it may be moved in the −X direction, and the X-ray tube 11 is moved in the direction along the rotating circumference by the rotating frame. You may let me. Further, the drive control function 51-5 may adjust the angle of the X-ray tube 11 or the angle of the X-ray detector 15 together with the movement control described above.

Further, the drive control function 51-5 may move both the X-ray tube 11 and the X-ray detector 15 described above from the reference position. For example, when both the X-ray detector movement amount and the X-ray tube movement amount associated with the imaging condition or the subject information are stored in the movement amount information 41-1, the X-ray tube 11 and the X-ray detector are stored. Move both of the fifteen. By moving both the X-ray tube 11 and the X-ray detector 15, the asymmetric positional relationship can be made larger than that of moving one of them within the spatial constraints of the gantry of the rotating frame 17.

Further, the drive control function 51-5 may change the moving direction depending on the shape of the X-ray detector 15. FIG. 8 is a diagram for explaining a moving direction when the shape of the X-ray detector is a plane detector. In the example of FIG. 8, instead of the X-ray detector 15 formed in an arc shape centered on the focal point of the X-ray tube 11, the X-ray detector 15 # formed in a plane shape is shown. In each of the plurality of X-ray detection element trains, a plurality of X-ray detection elements are arranged in the channel direction along the plane. A plurality of X-ray detection element sequences are arranged in the slice direction. In this case, the drive control function 51-5 horizontally moves the X-ray detector 15 # along the channel direction of the X-ray detector 15 #. That is, by moving the X-ray detector 15 # horizontally, the third drive device 15A horizontally moves the X-ray tube 11, the rotation center C0 of the X-ray tube 11, and the circumferential direction of the X-ray detector 15 during rotation. Make sure that the center C2 with respect to is not on the same straight line.

Further, when the X-ray detector 15 # is moved horizontally, the amount of movement is limited by the spatial limitation of the gantry of the rotating frame 17. For example, when the movement amount (distance D3) of the X-ray detector 15 # shown in FIG. 8 is large, the end portion of the X-ray detector 15 # comes into contact with the outer shape 17o of the rotating frame 17, and the X-ray detector 15 # rotates during the main scan. It may not be possible. Therefore, the drive control function 51-5 may control the movement direction so as to move the X-ray detector 15 # to a position where the movement amount can be secured. For example, the drive control function 51-5 changes the curvature of the locus of the central portion of the X-ray detector 15 # with respect to the circumferential direction by moving one or both of the X-ray tube 11 and the X-ray detector 15. ..

FIG. 9 is a diagram for explaining the moving direction of the X-ray detector 15 #. In the example of FIG. 9, the locus T1 shows the rotating locus of the center C2 when the X-ray detector 15 # is in the reference position. When the X-ray detector 15 # is moved, the drive control function 51-5 moves the X-ray detector 15 # along a locus T2 in a direction having a smaller curvature (a larger radius of curvature) than the curve of the locus T1. As a result, the amount of movement can be made larger than that of moving horizontally. Further, the drive control function 51-5 sets the X-ray detector 15 # only at a predetermined angle θ2 so that the line perpendicular to the plane of the X-ray detector 15 # with respect to the center C2 faces the center of the X-ray tube 11. You may tilt it. The angle θ2 is included in, for example, the X-ray tube movement amount of the movement amount information 41-1.

Next, the state of generation of the reconstructed image at the time of executing this scan will be described with reference to the figure. FIG. 10 is a diagram for explaining the process of generating the reconstructed image in the first embodiment. This figure mainly shows the configuration mounted on the rotating frame 17, and some reference numerals and configurations are omitted. Further, it is assumed that the X-ray detector 15 is moved along the channel arrangement direction by the distance D1 as shown in FIG. The rotating frame 17 rotates the X-ray tube 11 and the X-ray detector 15 while maintaining the arrangement (second arrangement) of the moved X-ray tube 11 and the X-ray detector 15. The rotating frame 17 is assumed to rotate in the direction of arrow A1 (counterclockwise) shown in the figure. The rotation position of the X-ray tube 11 (in other words, the rotation position of the rotation frame 17) is recognized by the control device 18 that rotates the rotation frame 17, and the information is provided from the control device 18 to the processing circuit 50.

The scan control function 56 scans the subject by a scan method (for example, helical scan) based on a predetermined operation mode. The rotation positions RP1-1 to RP1-5 show, for example, the state of X-ray irradiation at each angle in the first rotation. The rotation position RP1-5 is a position equivalent to the rotation position RP2-1 where the second rotation is started.

For example, in the state of the rotation positions RP1-1 and RP1-5, the left side of the subject P2 shown in this figure (the left side of the subject P2 shown in the figure) is not detected. Therefore, when the scan control function 56 also includes the left side of the subject in the imaging range of the reconstructed image, the rotation position in which the left side of the subject P2 is included in the imaging range from the rotation position RP2-1 where the second rotation is started. A reconstructed image is generated using the detection data up to RP-2.

FIG. 11 is a diagram showing an example of the generated reconstructed image. As shown in FIG. 11, the image processing function 55 generates a reconstructed image of the nth rotation (n is an integer of 1 or more) among the detection data acquired according to the time after the start of the main scan. In this case, in addition to the detection data obtained by n rotations, the detection data of a part of the n + 1th rotation (more specifically, the detection data up to the rotation angle including the shooting range of the portion outside the irradiation range). Is used to generate a reconstructed image of the nth rotation.

When the detection data includes an acquisition target, the image processing function 55 generates a reconstructed image using the detection data acquired by n rotations without using a part of the detection data of n + 1 rotations. do.

As a result, if the imaging range includes the imaging target range of the reconstructed image based on the shape and size of the subject and the imaging target site, the imaging target can be captured in the reference position, and the imaging target can be included in the imaging range. When the range is not included, one or both of the X-ray detector 15 and the X-ray tube 11 can be moved by a required distance to capture a reconstructed image at an asymmetric position. Therefore, it is possible to widen the area that can be imaged while suppressing the deterioration of the image quality of the reconstructed image.

Further, the image processing function 55 complements and complements the projection data regarding the range located outside the detection range of the X-ray detector 15 by using, for example, a known technique as shown in Japanese Patent Application Laid-Open No. 2006-141999. The CT image may be reconstructed based on the projected projection data. Specifically, the image processing function 55 is at least based on the projection angle of the X-ray tube 11 and the coordinates of a range (interference point) located outside the detection range of the X-ray detector 15 with respect to the X-ray detector 15. Determine one complementary projection angle and the coordinates of at least one complementary point. Then, the image processing function 55 calculates at least one weight corresponding to at least one complement point, and when reconstructing the image to be scanned based on the calculated weight, the projection data regarding the scan target at the interpolation point is obtained. Complement.

Further, the image processing function 55 may interpolate an image in a range located outside the detection range of the X-ray detector 15 by using, for example, a known technique as shown in Japanese Patent Application Laid-Open No. 2019-180834. .. Specifically, the image processing function 55 performs a first scanno-photographing so as to irradiate X-rays while moving the top plate 33 or the X-ray tube 11 along the longitudinal direction of the top plate 33 to obtain the subject P. Generates a first scanno image showing a portion along the longitudinal direction. Further, the image processing function 55 may be used for a plurality of images along the longitudinal direction before the second scanno imaging in which the region including a part of the contour of the subject P protruding from the first scanno image in the lateral direction of the top plate is photographed. A second scanno image is taken so that the X-ray tube 11 is stationary at a plurality of positions in order to irradiate X-rays, and a plurality of second scanno images showing a region including a part of the contour are generated. do. Then, the image processing function 55 estimates the contour of the subject P based on each of the first scanno image and the second scanno image, and interpolates the contour of the unphotographed region based on the estimated contour. Generate a reconstructed image.

Further, the image processing function 55 may interpolate an image in a range located outside the detection range of the X-ray detector 15 by using, for example, a known technique as shown in Japanese Patent Application Laid-Open No. 2007-11515. .. Specifically, first, the scan control function 56 moves the X-ray tube 11 and the X-ray detector 15 to the first rotation angle position to acquire projection data from the first direction, and X. Scan control is performed by moving the wire tube 11 and the X-ray detector 15 to the second rotation angle position and acquiring projection data from the second direction. Next, the image processing function 55 synthesizes the projection data corresponding to the first direction and the projection data corresponding to the second direction to generate one scan range setting image. The known technique for interpolating an image in a range located outside the detection range of the X-ray detector 15 is not limited to the above example.

The drive control function 51-5 drives the X-ray tube 11 and the X-ray detector 15 to return to their original positions (reference positions) before the next shooting after the reconstructed image is generated by the main scan shooting. Control the device. The drive control function 51-5 is used when a plurality of scans are performed on the same subject, and the X-ray detector 15 and the X-ray tube 11 are moved so as to be in an asymmetrical position in the first scan. May continue the positional relationship as it is. Further, in the case where the body of the subject is scanned in the first scan and the head is scanned in the second scan, it is determined by the movement necessity determination function 51-4 that the head can be photographed even at the reference position. In this case, the drive control function 51-5 may control the X-ray detector 15 and the X-ray tube 11 to return to their original positions. An image taken at a symmetrical position (reference position) can acquire more detection data at the same position than an image taken at an asymmetric position, so that an image with good image quality can be obtained. Therefore, by acquiring the image at the reference position as much as possible, it is possible to acquire an image with better image quality. The drive control function 51-5 may perform control that the image quality is not restored when the image quality does not change as compared with the image at the symmetrical position even if the image remains at the asymmetric position.

FIG. 12 is a flowchart showing an example of the flow of processing executed by the X-ray CT apparatus according to the first embodiment. Hereinafter, the processing after receiving the input of the operation mode by the input interface 43 will be described. Further, before the start of the process in the first embodiment, and in the following, it is assumed that the X-ray tube 11 and the X-ray detector 15 are positioned at the reference position (symmetrical position). Further, in the following processing, an example of moving the X-ray tube 11 or the X-ray detector 15 will be described, but both the X-ray tube 11 and the X-ray detector 15 may be moved. The same shall apply in the description of the flowchart in the other embodiments.

In the example of FIG. 12, the image acquisition function 51-1 has an X-ray tube 11 and an X-ray detector based on an operation mode accepted by the input interface 43 (for example, an operation mode for acquiring a reconstructed image). A scanno image is acquired from the reference position of 15 (step S100). Next, the subject information acquisition function 51-2 acquires the subject information (step S102). Next, the imaging range determination function 51-3 determines the imaging range at the time of the main scan imaging based on the subject information (step S104).

Next, the movement necessity determination function 51-4 determines whether or not the X-ray tube 11 or the X-ray detector 15 needs to be moved based on the determined imaging range (step S106). When it is determined that the X-ray tube 11 or the X-ray detector 15 needs to be moved, the drive control function 51-5 acquires the movement amount of the X-ray tube 11 or the X-ray detector 15 (step S108). , The X-ray tube 11 or the X-ray detector 15 is moved from the reference position based on the acquired movement amount (step S110).

When it is determined that it is not necessary to move the X-ray tube 11 or the X-ray detector 15 after the processing of step S110 or in the processing of step S106, the scan control function 56 executes a scan (step S112). Next, the reconstruction processing function 54 performs a reconstruction processing of the data obtained by scanning (step S114). Next, the image processing function 55 executes image processing based on the reconstructed image (Steck S116). Next, the display control function 57 displays the image processed by the image processing function 55 on the display 42 or the like (step S118).

Next, the drive control function 51-5 determines whether or not to return to the reference position based on the operation mode or the like (step S120). When it is determined that it is necessary to return to the reference position, the drive control function 51-5 controls the drive device to return the X-ray detector 15 and the X-ray tube 11 from the moved position to the reference position (step S122). .. This ends the processing of this flowchart. If it is determined in the process of step S120 that it is not necessary to return to the reference position, the process of this flowchart is terminated.

In the above process, an example of moving the X-ray tube 11 or the X-ray detector 15 is shown, but both the X-ray tube 11 and the X-ray detector 15 may be moved. Further, the drive control function 51-5 may move the wedge 12 together with the X-ray tube 11 or may move the DAS 16 together with the X-ray detector 15. The same applies to the description of the processing in the following embodiments.

According to the first embodiment described above, the X-ray tube 11 or the X-ray detector 15 can be moved according to the size of the subject, and the reconstructed image can be captured in a more appropriate imaging range. .. Further, according to the first embodiment, when the shooting target range of the reconstructed image can be shot at the reference position, it can be shot at the reference position, so that the amount of detection data for the same portion is large. Therefore, there is no deterioration in image quality, and higher quality images can be obtained. Therefore, it is possible to widen the area that can be imaged while suppressing the deterioration of the image quality of the reconstructed image.

(Second embodiment)
Next, the X-ray CT apparatus according to the second embodiment will be described. The second embodiment is different from the first embodiment described above in that the X-ray tube 11 and the X-ray detector 15 are positioned in asymmetrical positions in advance when the scanno image is taken. Therefore, in the following, the differences will be mainly described. In the second embodiment, the arrangement positioned at the asymmetrical position is an example of the first arrangement. The same configuration as the X-ray CT apparatus 1 can be applied to the X-ray CT apparatus in the second embodiment. Therefore, in the following, the explanation will be made using the X-ray CT apparatus 1, and duplicate explanations will be omitted.

In the second embodiment, the drive control function 51-5 of the position control function 51 positions the X-ray tube 11 and the X-ray detector 15 asymmetrically when acquiring a scanno image by the image acquisition function 51-1. Drive the drive so that it moves to. For example, the drive control function 51-5 may move a predetermined amount of movement to the X-ray tube 11 or the X-ray detector 15, and can move to the maximum due to restrictions on the size of the rotating frame 17. The amount of movement may be moved. The predetermined movement amount is, for example, a movement amount estimated to include one end of the left and right ends of the subject P placed on the top plate 33 in the imaging range of the scanno image. Further, the drive control function 51-5 may move the X-ray tube 11 or the X-ray detector 15 based on the information regarding the movement amount input by the input interface 43. The information regarding the input movement amount may be, for example, any one of a plurality of predetermined FOV sizes (for example, S, M, L, LL, XL).

The image acquisition function 51-1 is, for example, in a state where the X-ray detector 15 is moved to the moving position shown in FIG. 5 by the drive control function 51-5 (the X-ray tube 11 and the X-ray detector 15 are in an asymmetric position). Acquires the scanno image taken in the state of In this case, the image acquisition function 51-1 interpolates the image in the other end range not included in the photographing range by using a known technique.

The subject information acquisition function 51-2 acquires subject information based on the scanno image acquired by the image acquisition function 51-1. In the second embodiment, since the scano imaging is performed at the asymmetric position, the entire region of the subject is included in the scanno image. Therefore, the imaging range determination function 51-3 can more appropriately determine the imaging range in this scan imaging for each subject based on the subject information acquired by the subject information acquisition function 51-2. ..

The movement necessity determination function 51-4 compares the imaging range by scanno imaging with the imaging target range at the time of the main scan, and determines whether or not it is necessary to move the X-ray tube 11 or the X-ray detector 15. .. For example, when the distance from the center of the imaging range to the center of the image range is more than a predetermined distance, it is determined that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved.

When it is determined by the movement necessity determination function 51-4 that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved, the drive control function 51-5 determines that the X-ray tube 11 or the X-ray detector 15 needs to be moved. Move one or both of the X-ray detectors 15. Further, the drive control function 51-5 captures the original position (scano image) of the X-ray tube 11 and the X-ray detector 15 before the next imaging after the main scan is completed and the reconstructed image is generated. Control the drive to return to the position for

FIG. 13 is a flowchart showing an example of the flow of processing executed by the X-ray CT apparatus in the second embodiment. The process shown in FIG. 13 is different from the process of S100 to S122 in the first embodiment described above in that the process of steps S200 to S206 is performed instead of the process of steps S100, S110, S120, and S122. It's different. Therefore, in the following, the processing of steps S200 to S206 will be mainly described. Before the start of the process shown in FIG. 13, it is assumed that the X-ray tube 11 or the X-ray detector 15 is positioned at a predetermined asymmetric position.

In the example of FIG. 13, the image acquisition function 51-1 acquires a scanno image from a state in which the X-ray tube 11 and the X-ray detector 15 are in an asymmetric position based on the operation mode accepted by the input interface 43 (step). S200). Next, the subject information acquisition function 51-2 acquires the subject information (step S102).

When it is determined in the process of step S106 that the X-ray tube 11 or the X-ray detector 15 needs to be moved, the drive control function 51-5 determines the amount of movement of the X-ray detector 15 or the X-ray detector 11. Acquired (step S108), and the X-ray tube 11 or the X-ray detector 15 is moved from the current position, which is an asymmetrical position, based on the acquired movement amount (step S202). By the process of step S202, the X-ray tube 11 and the X-ray detector 15 may be moved to a symmetrical position or may be moved to another asymmetrical position. If it is determined that it is not necessary to move the X-ray tube 11 or the X-ray detector 15 after the processing of step S202 or in the processing of step S106, the processing after step S112 is executed.

Further, after the processing of step S118, whether or not the drive control function 51-5 returns the positions of the X-ray detector 15 and the X-ray tube 11 to the original positions (positions for scanning scanno) based on the operation mode or the like. Is determined (step S204). When it is determined that it is necessary to return to the original position, the drive control function 51-5 controls the drive device to return the X-ray detector 15 and the X-ray tube 11 from the moved position to the original position (step). S206). As a result, the processing of this flowchart ends. If it is determined in the process of step S204 that it is not necessary to return to the original position, the process of this flowchart is terminated.

According to the second embodiment described above, the X-ray tube 11 and the X-ray detector 15 are positioned at asymmetric positions at the stage of capturing the scanno image, so that the scanno image is obtained even when the subject is large. Can include the entire subject. As a result, the size of the subject can be grasped more accurately, and the X-ray tube 11 and the X-ray detector 15 are positioned at more appropriate positions based on the imaging range and the imaging target range at the time of the main scan. be able to. Therefore, it is possible to widen the area that can be imaged while suppressing the deterioration of the image quality of the reconstructed image.

(Third embodiment)
Next, the X-ray CT apparatus according to the third embodiment will be described. Compared with the first embodiment, the X-ray CT apparatus according to the third embodiment is provided with a floodlight on the gantry device 10, and the size of the subject or the like is acquired by the light emitted from the floodlight to acquire X-rays. The difference is that one or both of the tube 11 and the X-ray detector 15 are moved. Therefore, in the following, the above differences will be mainly described. Further, in the following, it is assumed that the X-ray tube 11 and the X-ray detector 15 are positioned at the reference positions.

FIG. 14 is a diagram showing a configuration example of the X-ray CT apparatus 2 according to the third embodiment. The X-ray CT device 2 shown in FIG. 14 includes, for example, a gantry device 10, a sleeper device 30, and a console device 40. The gantry device 10, for example, includes an X-ray tube 11, a wedge 12, a collimator 13, an X-ray high voltage device 14, an X-ray detector 15, a data collection system 16, a rotating frame 17, and a control device 18. And a floodlight 60.

The floodlight 60 was placed on a top plate 33 or a top plate 33 in which a light (visible light) for alignment of the subject P, for example, a laser beam was inserted into the opening in response to an instruction from the control device 18. Project toward the subject P. The irradiation range of the light for alignment of the subject P allows the user to visually recognize the imaging range during the scanno imaging and the main scanning imaging. The color of the visible light emitted from the floodlight 60 may be any color, for example, a color such as red, green, or blue. In FIG. 14, two floodlights 60 are installed at positions where light can be projected from the left and right directions of the top plate 33, but the installation positions and the number of floodlights 60 are not limited to this. ..

When the user determines that it is necessary to move one or both of the X-ray tube 11 and the X-ray detector 15 based on the light projected by the floodlight 60, the X-ray tube 11 is connected to the input interface by 43. Alternatively, an instruction to move one or both of the X-ray detectors 15 from the reference position is input. When it is determined by the user that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved, for example, the main scan is performed in the irradiation range of the light emitted from the floodlight 60 to the subject P. This is the case when the shooting range of the time is not included. In this case, the user inputs an instruction to move one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position by the input interface 43. As an example of a predetermined case, the input interface 43 receives an instruction to move one or both of the X-ray tube 11 and the X-ray detector 15 after projecting light from the floodlight 60. The instruction is output to the position control function 51.

The position control function 51 is based on an instruction to move one or both of the X-ray tube 11 or the X-ray detector 15 input to the input interface by 43, and the position control function 51 is one of the X-ray tube 11 or the X-ray detector 15. Alternatively, both are moved to a predetermined amount of movement. The predetermined movement amount may be, for example, the maximum movement amount that one or both of the X-ray tube 11 and the X-ray detector 15 can move, and is a predetermined movement amount that is less than the maximum movement amount. You may. The image acquisition function 51-1 acquires a scanno image taken by a scanno after moving one or both of the X-ray tube 11 and the X-ray detector 15. Further, when the image acquisition function 51-1 does not accept the input of the information for moving one or both of the X-ray tube 11 and the X-ray detector 15 from the reference position and the information regarding the movement amount, the image acquisition function 51-1 of the reference position. Acquire the scanno image taken by the scanno as it is.

FIG. 15 is a flowchart showing an example of the flow of processing executed by the X-ray CT apparatus according to the third embodiment. The process shown in FIG. 15 is different from the process of S100 to S122 in the first embodiment described above in that the process of steps S300 to S306 is performed instead of the process of steps S100 and S102. Therefore, in the following, the processing of steps S300 to S306 will be mainly described. Before the start of the process shown in FIG. 15, it is assumed that the X-ray detector 15 and the X-ray tube 11 are positioned at the reference positions.

In the example of FIG. 15, the image acquisition function 51-1 irradiates light from the floodlight 60 (step S300). Next, the image acquisition function 51-1 determines whether or not an instruction to move the X-ray tube 11 or the X-ray detector 15 has been received by the input interface 43 (step S302). When it is determined that the instruction to move the X-ray tube 11 or the X-ray detector 15 has been received, the drive control function 51-5 moves the X-ray detector 15 or the X-ray tube from the reference position in advance. Move only (step S304). As a result, the X-ray tube 11 and the X-ray detector 15 have an asymmetrical positional relationship.

If it is determined that the instruction to move the X-ray tube 11 or the X-ray detector 15 is not accepted after the processing of step S304 or in the processing of step S302, the image acquisition function 51-1 acquires a scanno image. (Step S306), the processes after step S104 are executed.

According to the third embodiment described above, the user confirms the imaging position of the subject P with the floodlight 60 before capturing the scanno image, and if necessary, the X-ray tube 11 and the X-ray detector. The position of 15 can be moved. As a result, it is possible to widen the region that can be imaged while suppressing the deterioration of the image quality of the reconstructed image according to the size of the subject P, the shooting position, and the like. Further, when it is possible to shoot an X-ray image at a reference position, it is possible to shoot the X-ray image at the reference position, so that a reconstructed image with better image quality can be obtained.

(Fourth Embodiment)
Next, the X-ray CT apparatus according to the fourth embodiment will be described. Compared with the first embodiment, the X-ray CT apparatus according to the fourth embodiment is provided with an image pickup device on the gantry device 10, and is based on an image including a subject imaged by the image pickup device. The difference is that one or both of the 11 or the X-ray detector 15 is moved from the reference position, and therefore, the above difference will be mainly described below. Further, in the following, it is assumed that the X-ray tube 11 and the X-ray detector 15 are positioned at the reference positions.

FIG. 16 is a diagram showing a configuration example of the X-ray CT apparatus 3 according to the fourth embodiment. The X-ray CT device 3 includes, for example, a gantry device 10, a sleeper device 30, and a console device 40. The gantry device 10, for example, includes an X-ray tube 11, a wedge 12, a collimator 13, an X-ray high voltage device 14, an X-ray detector 15, a data collection system 16, a rotating frame 17, and a control device 18. And a camera (an example of an image pickup device) 61.

The camera 61 is a digital camera that uses a solid-state image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). Further, the camera 61 includes, for example, an optical system mechanism such as a lens and an aperture, and an electronic system mechanism such as a light receiving element and a memory. The camera 61 is installed, for example, at a position and a posture in which a subject P placed on the sleeper device 30 can be imaged. For example, the camera 61 is installed above the ceiling of the examination room or the gantry. Further, the number of cameras 61 may be one or a plurality. The image pickup operation of the camera 61 is controlled by the processing circuit 50, and the acquired image data (hereinafter referred to as a camera image) is output to the processing circuit 50. For example, the photographing area photographed by the camera 61 may be associated with the irradiation range of X-rays emitted from the X-ray tube 11.

In the fourth embodiment, the image acquisition function 51-1 acquires a camera image captured by the camera 61. The subject information acquisition function 51-2 performs processing such as binarization and graph cutting on the camera image acquired by the image acquisition function 51-1, and features features such as brightness extraction and edge extraction based on the processing results. The position of the subject P included in the image capture area of the camera image by performing the image analysis to be extracted and using the feature information obtained by the image analysis and a method such as pattern matching using a template for each part prepared in advance. The subject information including the (region), the size, the position of the part (for example, the head, the chest, the arm, the abdomen), etc. is acquired. Further, the subject information acquisition function 51-2 may acquire subject information based on the information input by the input interface 43.

The imaging range determination function 51-3 determines the imaging range of the reconstructed image at the time of the main scan based on the information acquired by the subject information acquisition function 51-2.

The movement necessity determination function 51-4 moves one or both of the X-ray tube 11 and the X-ray detector 15 based on the imaging range determined by the imaging range determination function 51-3. For example, the movement necessity determination function 51-4 needs to move one or both of the X-ray tube 11 and the X-ray detector 15 when the shooting range does not include the shooting target range in the main scan shooting. Judge that there is. On the other hand, the movement necessity determination function 51-4 determines that it is not necessary to move the positions of the X-ray tube 11 and the X-ray detector 15 from the reference position when the imaging target range is included in the imaging range. ..

When it is determined that it is necessary to move one or both of the X-ray tube 11 and the X-ray detector 15 as an example of a predetermined case, the drive control function 51-5 takes a picture in the main scan picture in the picture range. One or both of the X-ray tube 11 and the X-ray detector 15 are moved by the drive device (first drive device 11A, third drive device 15A) so as to include the target range.

FIG. 17 is a flowchart showing an example of the flow of processing executed by the X-ray CT apparatus 3 in the fourth embodiment. The process shown in FIG. 17 is different from the process of S100 to S122 in the first embodiment described above in that the process of steps S400 to S402 is performed instead of the process of steps S100 to S102. Therefore, in the following, the processing of steps S400 to S402 will be mainly described. Before the start of the process shown in FIG. 17, it is assumed that the X-ray detector 15 and the X-ray tube 11 are positioned at the reference positions.

In the example of FIG. 17, the image acquisition function 51-1 acquires a camera image from the camera 61 (step S400). Next, the subject information acquisition function 51-2 acquires subject information based on the camera image (step S402). Next, the processes after step S104 are executed.

According to the fourth embodiment described above, the position and size of the subject P are acquired based on the camera image taken by the camera 61, and the X-ray tube 11 or the X-ray tube 11 or according to the acquired position and size. One or both of the X-ray detectors 15 can be moved to capture a reconstructed image. Further, when it is possible to take an X-ray image at a reference position, it is possible to take a picture with the reference position as it is, so that an image with better image quality can be obtained. Further, according to the fourth embodiment, the shooting range can be determined without shooting a scanno image. In the fourth embodiment, the camera image taken in the shooting range of the camera 61 is an example of the first image shot in the first range. Further, the positions of the X-ray tube 11 and the X-ray detector 15 (reference positions in the above example) at the time of taking a picture with the camera 61 are an example of the first arrangement.

(Fifth Embodiment)
Next, the X-ray CT apparatus according to the fifth embodiment will be described. The X-ray CT apparatus according to the fifth embodiment has an X-ray tube 11 or X based on the imaging information of the subject P, instead of determining the imaging range, as compared with the first to fourth embodiments. The difference is that it determines whether one or both of the line detectors 15 need to be moved. Therefore, the above differences will be mainly described below. Further, in the fifth embodiment, the same X-ray CT apparatus as in the first to fourth embodiments described above can be used, and therefore, the X-ray CT apparatus 1 will be described as an example. Further, in the fifth embodiment, the position control function 51 may not have the shooting range determination function 51-3.

The imaging information of the subject P includes, for example, imaging history information and an imaging protocol when the subject P has executed the main scan imaging in the past. The imaging history information is associated with, for example, imaging conditions, subject information, and information regarding the positions of the X-ray detector 15, the X-ray tube 11, the X-ray detector 15, and the collimator 13. The imaging history information may be generated for each subject. In this case, the imaging history information is identified by the identification information that identifies the subject P. The imaging protocol includes, for example, imaging of the shape and size of the subject P to be imaged, the angle position where X-ray irradiation is performed on the part to be imaged, the X-ray irradiation range, the irradiation timing, the reconstruction area, and the like. Various conditions are associated. In addition to the above contents, the photographing protocol may include information regarding the position of the X-ray tube 11, the position of the X-ray detector 15, and the position of the collimator 13. A plurality of imaging protocols may be generated for each of the shape and size of the subject P to be imaged and the part to be imaged, for example. The shooting information is stored in, for example, the memory 41.

The subject information acquisition function 51-2 of the position control function 51 is, for example, information about the subject P input by the input interface 43 or the like (for example, identification information for identifying the subject P, or the shape or size of the subject P). The imaging information corresponding to the subject P is acquired from the imaging information stored in the memory 41 based on the information regarding the interface) and the imaging conditions.

The movement necessity determination function 51-4 determines whether or not it is necessary to move one or both of the X-ray tube 11 and the X-ray detector 15 based on the acquired imaging information. For example, in the movement necessity determination function 51-4, the positions of the X-ray tube 11 and the X-ray detector 15 included in the acquired imaging information are different from the current positions of the X-ray tube 11 and the X-ray detector 15. In this case, it is determined that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved. Further, in the movement necessity determination function 51-4, the positions of the X-ray tube 11 and the X-ray detector 15 included in the imaging information are at the same positions as the current positions of the X-ray tube 11 and the X-ray detector 15. In some cases, it is determined that it is not necessary to move one or both of the X-ray tube 11 and the X-ray detector 15.

As an example of a predetermined case, the drive control function 51-5 determines that one or both of the X-ray tube 11 and the X-ray detector 15 need to be moved by the movement necessity determination function 51-4. In addition, one or both of the X-ray tube 11 and the X-ray detector 15 are moved by the drive device (first drive device 11A, third drive device 15A). For example, the drive control function 51-5 sets the amount of movement so that the current positions of the X-ray tube 11 and the X-ray detector 15 are the positions of the X-ray tube 11 and the X-ray detector 15 included in the imaging information. It is acquired, and one or both of the X-ray tube 11 and the X-ray detector 15 are moved based on the acquired movement amount.

FIG. 18 is a flowchart showing an example of the flow of processing executed by the X-ray CT apparatus according to the fifth embodiment. The process shown in FIG. 18 is different from the process of S100 to S122 in the first embodiment described above in that the process of step S500 is performed instead of the process of steps S100 to S104. Therefore, in the following, the processing of step S500 will be mainly described.

In the example of FIG. 18, the subject information acquisition function 51-2 acquires the imaging information of the subject P (step S500). Next, the movement necessity determination function 51-4 determines whether or not the X-ray tube 11 or the X-ray detector 15 needs to be moved based on the acquired shooting information (step S106), and thereafter. The process is executed.

According to the fifth embodiment described above, the X-ray tube 11 and X-rays can be detected more quickly based on the imaging history information and the imaging information such as the imaging protocol when the subject P has performed the main scan imaging in the past. The detector 15 can be moved to an appropriate position. Further, according to the fifth embodiment, the X-ray tube 11 and the X-ray detector 15 can be moved without taking a scanno image.

Each of the first to fifth embodiments described above may be combined with some or all of the other embodiments. For example, by combining the third embodiment and the fourth embodiment, an image including the light projected on the subject P by the floodlight 60 is photographed by the camera 61, and the photographed camera image is analyzed. The range may be determined. This makes it possible to acquire a more accurate shooting range.

Further, in the fourth embodiment, not only the camera image but also the scanno image may be captured. For example, when photographing an external part such as the chest or the entire abdomen, the imaging range is determined using a camera image or the like, and when photographing a specific organ, a scanno image is photographed and the internal structure included in the scanno image is taken. It may be determined whether or not the X-ray tube 11 and the X-ray detector 15 need to be moved based on the imaging target range. Further, in the third and fourth embodiments, the X-ray tube 11 and the X-ray detector 15 are changed to a state of being positioned at a reference position (symmetrical position), and the X-ray tube is similarly positioned as in the second embodiment. Each process may be performed with the 11 and the X-ray detector 15 positioned at asymmetric positions. Further, in the present embodiment, whether or not the scanno imaging and the main scanning imaging are in an asymmetric state, and how much one or both of the X-ray tube 11 and the X-ray detector 15 are moved according to a predetermined protocol. You may associate the information.

In the above-described embodiment, for example, a so-called multi-tube type X-ray is obtained by mounting a plurality of pairs of an X-ray tube 11 and an X-ray detector 15 on a rotating ring in a single-tube type X-ray CT apparatus. It can also be applied to CT devices.

The embodiment described above can be expressed as follows.
An X-ray tube that irradiates X-rays while rotating,
An X-ray detector that detects X-rays emitted from the X-ray tube,
A rotating portion that rotates the X-ray tube and the X-ray detector around the rotation center of the X-ray tube, and
A drive device that exists in the rotating part and moves one or both of the X-ray tube and the X-ray detector.
A storage device that stores the program and
With a hardware processor,
By executing the program, the hardware processor
In certain cases, the drive device moves one or both of the X-ray tube or the X-ray detector in a direction intersecting the radial direction of the rotation.
An X-ray CT apparatus configured as such.

1, 2, 3 ... X-ray CT device, 10 ... Stand device, 30 ... Sleep device, 40 ... Console device, 41 ... Memory, 42 ... Display, 43 ... Input interface, 44 ... Network connection circuit, 50 ... Processing circuit, 51 ... Position control function, 51-1 ... Image acquisition function, 51-2 ... Subject information acquisition function, 51-3 ... Imaging range determination function, 51-4 ... Movement necessity determination function, 51-5 ... Drive control function , 52 ... system control function, 53 ... preprocessing function, 54 ... reconstruction processing function, 55 ... image processing function, 56 ... scan control function, 57 ... display control function, 60 ... floodlight, 61 ... camera

Claims (15)

An X-ray tube that irradiates X-rays while rotating,
An X-ray detector that detects X-rays emitted from the X-ray tube,
A rotating portion that rotates the X-ray tube and the X-ray detector around the rotation center of the X-ray tube, and
A drive device that exists in the rotating part and moves one or both of the X-ray tube and the X-ray detector.
A drive control unit that moves one or both of the X-ray tube and the X-ray detector in a direction intersecting the radial direction of the rotation in the drive device in a predetermined case.
X-ray CT apparatus. Control to obtain a first image of a first range of a subject by performing imaging with one or both of the X-ray tube or the X-ray detector in the first arrangement, and the X-ray tube or Control to obtain a second image in a second range different from the first range of the subject by performing imaging with one or both of the X-ray detectors in the second arrangement. Further prepare the part,
The X-ray CT apparatus according to claim 1. By moving one or both of the X-ray tube and the X-ray detector, the drive device makes the X-ray tube, the rotation center, and the center of the X-ray detector in the circumferential direction the same. Make sure it is not in a straight line,
The X-ray CT apparatus according to claim 1 or 2. The rotating portion includes a rotation support portion that rotates the X-ray tube and the X-ray detector around the rotation center, the rotation support portion, the X-ray tube, the X-ray detector, and the driving device. Including the gantry that houses the
The drive device moves one or both of the X-ray tube and the X-ray detector within a range that does not come into contact with the gantry.
The X-ray CT apparatus according to any one of claims 1 to 3. The drive device changes the curvature of the locus of the central portion with respect to the circumferential direction of the X-ray detector by moving the X-ray detector.
The X-ray CT apparatus according to any one of claims 1 to 4. Further, an imaging range determining unit for determining the imaging range of the subject by the X-ray is provided.
The predetermined case is a case where it is necessary to move one or both of the X-ray tube and the X-ray detector based on the imaging range determined by the imaging range determining unit.
The X-ray CT apparatus according to any one of claims 1 to 5. Further provided with an acquisition unit for acquiring an image of the subject,
The imaging range determination unit determines the shape of the subject obtained from the image acquired by the acquisition unit, the distance from the X-ray tube to the X-ray detector, and the position of the channel of the X-ray detector. Based on this, the shooting range is determined.
The X-ray CT apparatus according to claim 6. The drive control unit sets the X-ray detector in the arrangement direction of a plurality of channels arranged in the X-ray detector so that the shooting target range is included in the shooting range determined by the shooting range determination unit. Move along,
The X-ray CT apparatus according to claim 6 or 7. Further equipped with a floodlight that projects light onto the subject,
In the above-mentioned predetermined case, when it is determined that it is necessary to move one or both of the X-ray tube and the X-ray detector based on the irradiation range of the light irradiated to the subject by the floodlight. Is,
The X-ray CT apparatus according to any one of claims 1 to 8. Further equipped with an imaging device for imaging the subject,
In the above-mentioned predetermined case, when it is determined that it is necessary to move one or both of the X-ray tube and the X-ray detector based on the image including the subject captured by the imaging device. be,
The X-ray CT apparatus according to any one of claims 1 to 9. The predetermined case is a case where it is determined that it is necessary to move one or both of the X-ray tube and the X-ray detector based on the imaging information of the subject.
The X-ray CT apparatus according to any one of claims 1 to 10. The drive device returns the X-ray tube and the X-ray detector to the positions before moving after the X-ray imaging of the imaging range is completed.
The X-ray CT apparatus according to any one of claims 1 to 11. The drive device further drives a collimator that adjusts the irradiation range of X-rays emitted from the X-ray tube.
After moving one or both of the X-ray tube and the X-ray detector, the drive control unit irradiates the range where the X-ray detector exists with the X-rays emitted by the X-ray tube. To move the collimeter so as to
The X-ray CT apparatus according to any one of claims 1 to 12. An X-ray tube that irradiates X-rays while rotating, an X-ray detector that detects X-rays emitted from the X-ray tube, and the X-ray tube and the X-ray detector are rotated. A computer of an X-ray CT apparatus including a rotating portion that rotates around a center and a driving device that exists in the rotating portion and moves one or both of the X-ray tube or the X-ray detector.
In certain cases, the drive device moves one or both of the X-ray tube or the X-ray detector in a direction intersecting the radial direction of the rotation.
Control method of X-ray CT apparatus. An X-ray tube that irradiates X-rays while rotating, an X-ray detector that detects X-rays emitted from the X-ray tube, and the X-ray tube and the X-ray detector are rotated. A computer of an X-ray CT apparatus comprising a rotating portion that rotates about a center and a driving device that exists in the rotating portion and moves one or both of the X-ray tube or the X-ray detector.
In certain cases, the drive device moves one or both of the X-ray tube or the X-ray detector in a direction intersecting the radial direction of the rotation.
program.

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