JP2019201823A - X-ray CT apparatus and X-ray tube control apparatus - Google Patents

Abstract

To complete scanning quickly while reducing exposure to an X-ray when complementing detection data in a period when an error occurs.SOLUTION: An X-ray tube is supported by a rotary frame and irradiates an X-ray toward the center of rotation while rotating. An X-ray detector detects intensity of the X-ray irradiated by the X-ray tube and passing through a subject. A specification unit detects that an error occurs in irradiation of the X-ray tube, and specifies a range of a rotation angle of the X-ray tube when the error occurs. When occurrence of the error in the irradiation of the X-ray tube is detected by the specification unit, a control unit causes the X-ray tube to continue the X-ray irradiation, then causes the X-ray tube to suspend the X-ray irradiation in the range of the rotation angle in which detection data is acquired by the X-ray detector, and then executes error control to cause the X-ray tube to irradiate the X-ray in the range of the rotation angle of the X-ray tube when the error occurs.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an X-ray CT apparatus and an X-ray tube control apparatus.

  Conventionally, an X-ray CT apparatus that obtains a tomographic image by irradiating a subject with X-rays and scanning is known. In the X-ray CT apparatus, a temporary error may occur due to a cause such as abnormal discharge occurring in the X-ray tube. In relation to this, it is disclosed to reduce the influence of an error when performing a helical scan that scans while moving a subject. However, in the conventional technique, when scanning with X-rays while the subject is stopped, the scan is promptly performed while reducing exposure by X-rays when supplementing the detection data during the period in which the error has occurred. There was a case that could not be completed.

JP 2014-236869 A JP 2003-135448 A International Publication No. 2014/109400

  The problem to be solved by the present invention is to complete scanning promptly while reducing exposure by X-rays when complementing detection data during a period in which an error has occurred.

  The X-ray CT apparatus according to the embodiment includes an X-ray tube, an X-ray detector, a specifying unit, and a control unit. The X-ray tube is supported by a rotating frame and emits X-rays toward the center of rotation while rotating. The X-ray detector detects the intensity of X-rays irradiated by the X-ray tube and passed through the subject. The specifying unit detects that an error has occurred in the irradiation of the X-ray tube, and specifies a range of a rotation angle of the X-ray tube when the error occurs. When the controller detects that an error has occurred in the irradiation of the X-ray tube, the control unit continues the X-ray irradiation to the X-ray tube, and then continues the X-ray detection. The X-ray tube is stopped from irradiating the X-ray tube in the range of the rotation angle at which the detection data is acquired by the detector, and after the stop, in the range of the rotation angle of the X-ray tube when the error occurs. Error control for causing the X-ray tube to perform X-ray irradiation is performed.

1 is a configuration diagram of an X-ray CT apparatus according to an embodiment. 6 is a flowchart showing an overview of processing until completion of scanning executed in the X-ray CT apparatus according to the embodiment. The figure for demonstrating the content of the process by a scan control function. The figure for demonstrating the content of the process by the apparatus of a comparative example. The flowchart (the 1) which shows an example of the flow of the process performed by a scan control function. 6 is a flowchart (part 2) illustrating an example of a flow of processing executed by a scan control function.

  Hereinafter, an X-ray CT apparatus and an X-ray tube control apparatus according to embodiments will be described with reference to the drawings. An X-ray CT apparatus is an apparatus that scans (photographs) the inside of a subject with X-rays and generates three-dimensional CT image data, a cross-sectional image, and the like. In the following description, it is assumed that the object is introduced and scanned inside the rotating frame (rotation center) while being placed on the top plate of the bed apparatus, but as will be appropriately noted, the X-ray CT apparatus Various modifications can be made to this embodiment.

[Constitution]
FIG. 1 is a configuration diagram of an X-ray CT (Computed Tomography) apparatus 1 according to an embodiment. The X-ray CT apparatus 1 includes, for example, a gantry device 10, a bed device 30, and a console device 40. For convenience of explanation, FIG. 1 shows both a view of the gantry device 10 viewed from the Z-axis direction and a view of the gantry device 10 viewed from the X-axis direction. In the embodiment, the rotational axis of the rotating frame 17 in the non-tilt state or the longitudinal direction of the top plate 33 of the bed apparatus 30 is orthogonal to the Z-axis direction and the Z-axis direction, and the axis that is horizontal to the floor surface is the X-axis. The direction perpendicular to the direction and the Z-axis direction and perpendicular to the floor surface is defined as the Y-axis direction.

  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 referred to as DAS: Data Acquisition System) 16. The rotating frame 17 and the control device 18 are included.

  The X-ray tube 11 generates X-rays by irradiating thermoelectrons from the cathode (filament) to 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 thermoelectrons.

  The wedge 12 is a filter for adjusting the X-ray dose irradiated to the subject P from the X-ray tube 11. The wedge 12 attenuates the X-rays that pass through itself so that the distribution of the X-ray dose irradiated 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 formed by processing aluminum so as to have a predetermined target angle or a predetermined thickness, for example.

  The collimator 13 is a mechanism for narrowing the irradiation range of X-rays that have passed through the wedge 12. For example, the collimator 13 narrows the X-ray irradiation range by forming a slit by combining a plurality of lead plates. The collimator 13 is sometimes called an X-ray stop.

  The X-ray high voltage device 14 includes, for example, a high voltage generation device and an X-ray control device. The high voltage generator has an electric circuit including a transformer and a rectifier, and generates a high voltage to be applied to the X-ray tube 11. The X-ray controller 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 with the above-described transformer, or one that boosts with an inverter. The X-ray high voltage device 14 may be provided on the rotating frame 17 or on the fixed frame (not shown) side of the gantry device 10. Further, the X-ray high voltage apparatus 14 has an error detection function 14A. This will be described later.

  The X-ray detector 15 detects the intensity of X-rays generated by the X-ray tube 11 and incident through the subject P. The X-ray detector 15 outputs an electrical signal (may be an optical signal or the like) corresponding to the detected X-ray intensity to the DAS 18. The X-ray detector 15 has, for example, a plurality of X-ray detection element arrays. Each of the plurality of X-ray detection element arrays has a plurality of X-ray detection elements arranged in the channel direction along an arc centered on the focal point of the X-ray tube 11. The plurality of X-ray detection element arrays are arranged in the slice direction (column 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 of a light amount corresponding to the intensity of incident X-rays. The grid is disposed on a surface of the scintillator array where X-rays are incident, and has an X-ray shielding plate having a function of absorbing scattered X-rays. The grid may be called a collimator (one-dimensional collimator or two-dimensional collimator). The optical sensor array includes, for example, an optical sensor such as a photomultiplier tube (photomultiplier: PMT). The optical sensor array outputs an electrical signal corresponding 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 electrical signals.

  The DAS 16 includes, for example, an amplifier, an integrator, and an A / D converter. The amplifier performs an amplification process on the electric signal output by each X-ray detection element of the X-ray detector 15. The integrator integrates the amplified electric signal over a view period (described later). The A / D converter converts an electrical signal indicating the integration result into a digital signal. The DAS 16 outputs 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, column number, and view number indicating the collected view of the source X-ray detection element. The view number is a number that changes according to the rotation of the rotating frame 17, for example, a number that is incremented according to the rotation of the rotating frame 17. Therefore, the view number is information indicating the rotation angle of the X-ray tube 11. The view period is a period that falls between a rotation angle corresponding to a certain view number and a rotation angle corresponding to the next view number. The DAS 16 may detect the switching of the view by a timing signal input from the control device 18, may be detected by an internal timer, or may be detected by a signal acquired from a sensor (not shown). . In the case of performing a full scan, when X-rays are continuously emitted from the X-ray tube 11, the DAS 16 collects a detection data group for the entire circumference (for 360 degrees). When X-rays are continuously emitted from the X-ray tube 11 in the case of performing a half scan, the DAS 16 collects detection data for a half circumference (for 180 degrees).

  The rotating frame 17 is an annular member that supports the X-ray tube 11, the wedge 12, the collimator 13, and the X-ray detector 15 so as to face each other. The rotating frame 17 is supported by a fixed frame so as to be rotatable about the subject P introduced therein. The rotating frame 17 further supports the DAS 16. The detection data output from the DAS 16 includes 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. Note that the detection data transmission method from the rotating frame 17 to the non-rotating portion is not limited to the above-described method using optical communication, and any non-contact transmission method may be employed. The rotary frame 17 is not limited to an annular member as long as it can support and rotate the X-ray tube 11 or the like, and may be a member such as an arm.

  The X-ray CT apparatus 1 is, for example, a Rotate / Rotate-Type X-ray CT apparatus (third) in which both the X-ray tube 11 and the X-ray detector 15 are supported by the rotating frame 17 and rotate around the subject P. However, the present invention is not limited thereto, and a plurality of X-ray detection elements arranged in an annular shape are fixed to a fixed frame, and a Stationary / Rotate-Typwno X-ray in which the X-ray tube 11 rotates around the subject P It may be a CT apparatus (fourth generation CT).

  The control device 18 includes, for example, a processing circuit having a processor such as a CPU (Central Processing Unit) and a driving 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 operations of the gantry device 10 and the couch device 30. For example, the control device 18 rotates the rotating frame 17, tilts the gantry device 10, or moves the top plate 33 of the bed 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 rotating frame 17 based on the output of a sensor (not shown). The control device 18 provides the rotation angle of the rotating frame 17 to the scan control function 55 as needed. The control device 18 may be provided in the gantry device 10 or may be provided in the console device 40. Further, the processing circuit of the control device 18 has a specific function 18A. This will be described later.

  The couch device 30 is a device that places and moves the subject P to be scanned and introduces it into the rotating frame 17 of the gantry device 10. The couch device 30 includes, for example, a base 31, a couch driving device 32, a top plate 33, and a support frame 34. The base 31 includes a housing that supports the support frame 34 so as to be movable in the vertical direction (Y-axis direction). The bed driving device 32 includes a motor and an actuator. The couch driving 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-like member on which the subject P is placed.

  The couch driving device 32 may move not only the top plate 33 but also the support frame 34 in the longitudinal direction of the top plate 33. In contrast to the above, the gantry device 10 may be moved in the Z-axis direction, and the rotation frame 17 may be controlled to come around the subject P by the movement of the gantry device 10. Moreover, the structure which can move both the gantry 10 and the top plate 33 may be sufficient. The X-ray CT apparatus 1 may be an apparatus that scans the subject P in a standing position or a sitting position. In this case, the X-ray CT apparatus 1 has a subject support mechanism instead of the bed apparatus 30, and the gantry apparatus 10 rotates the rotary frame 17 around an axial direction perpendicular to the floor surface.

  The console device 40 includes, for example, a memory 41, a display 42, an input interface 43, and a processing circuit 50. In the embodiment, the console device 40 is described as a separate body from the gantry device 10, but the gantry device 10 may include some or all of the components 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, detection data, projection data, reconstructed image data, CT image data, and the like. These data may be stored not in the memory 41 (or in addition to the memory 41) but in an external memory with which the X-ray CT apparatus 1 can communicate. The external memory is controlled by the cloud server when, for example, the cloud server that manages the external memory receives a read / write request.

  The display 42 displays various information. For example, the display 42 displays a medical image (CT image) generated by the processing circuit, a GUI (Graphical User Interface) image that accepts various operations by the operator, and the like. 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 in the gantry device 10. The display 42 may be a desktop type or a display device (for example, a tablet terminal) that can wirelessly communicate with the main body of the console device 40.

  The input interface 43 receives various input operations by the operator and outputs an electrical signal indicating the contents of the received input operation to the processing circuit 50. For example, the input interface 43 includes a collection condition when collecting detection data or projection data (described later), a reconstruction condition when reconstructing a CT image, an image processing condition when generating a post-process image from a CT image, and the like. The input operation is accepted. For example, the input interface 43 is realized by a mouse, keyboard, touch panel, drag ball, switch, button, joystick, camera, infrared sensor, microphone, or the like. The input interface 43 may be provided in the gantry device 10. The input interface 43 may be realized by a display device (for example, a tablet terminal) that can wirelessly communicate with the main body of the console device 40.

  The processing circuit 50 controls the overall operation of the X-ray CT apparatus 1. The processing circuit 50 executes, for example, a system control function 51, a preprocessing function 52, a reconstruction processing function 53, an image processing function 54, a scan control function 55, a display control function 56, and the like. These components are realized, for example, when a hardware processor such as a CPU (Central Processing Unit) executes a program (software). Some or all of these components are hardware (circuit units) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit); (including circuitry), or may be realized by cooperation of software and hardware. The program may be stored in advance in a non-transitory storage device such as the memory 41 or stored in a removable non-transitory storage medium such as a DVD or CD-ROM. It may be installed by being attached to the drive device.

  Each component included in the console device 40 or the processing circuit 50 may be distributed and realized by a plurality of hardware. The processing circuit 50 is not a configuration of the console device 40 but may be realized by a processing device that can communicate with the console device 40. The processing apparatus is, for example, a workstation (one connected to one X-ray CT apparatus or a plurality of X-ray CT apparatuses connected to the processing circuit 50 described below). For example, a cloud server).

  The system control function 51 controls various functions of the processing circuit 50 based on the input operation received by the input interface 43.

  The preprocessing function 52 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 the DAS 16, and generates projection data. Projection data is stored in the memory 41.

  The reconstruction processing function 53 performs the reconstruction processing by the filtered back projection method, the successive approximation reconstruction method, or the like on the projection data generated by the preprocessing function 52 to generate and generate CT image data. The CT image data is stored in the memory 41.

  The image processing function 54 converts CT image data into three-dimensional image data or cross-sectional image data of an arbitrary cross section by a known method based on an input operation received by the input interface 43. The conversion to the three-dimensional image data may be performed by the preprocessing function 52.

  The scan control function 55 controls detection data collection processing in the gantry device 10 by instructing the X-ray high-voltage device 14, the DAS 16, the control device 18, and the bed driving device 32. The scan control function 55 controls the operation of each unit when capturing a positioning image and capturing an image used for diagnosis. The scan control function 55 is an example of a “control unit”.

  With the above configuration, the X-ray CT apparatus 1 scans the subject P in a manner such as helical scan, conventional scan, step-and-shoot. The helical scan is a mode in which the subject P is scanned spirally by rotating the rotating frame 17 while moving the top plate 33. The conventional scan is an aspect in which the subject P is scanned in a circular orbit by rotating the rotating frame 17 while the top plate 33 is stationary. Run a conventional scan. The step-and-shoot is an aspect in which a conventional scan is performed in a plurality of scan areas by moving the position of the top plate 33 at regular intervals.

  FIG. 2 is a flowchart showing an outline of processing until completion of scanning executed in the X-ray CT apparatus 1 according to the embodiment. Note that the order shown in the flowchart can be changed, added, or deleted as appropriate.

  First, the system control function 51 of the X-ray CT apparatus 1 accepts input of patient information (information on the subject P) to the input interface 43 while displaying an interface screen on the display 42 (step S100). Next, the system control function 51 accepts selection of a target part for the input interface 43 (step S102). For example, a graphic area for selecting a target part is displayed on the display 42, and the user designates the target part by selecting one of the graphic areas. Next, the system control function 51 accepts selection of a scan mode for the input interface 43 (step S104). Next, the system control function 51 receives input of various parameters to the input interface 43 (step S106).

  Next, the system control function 51 instructs the scan control function 55 to take a scanogram for positioning (step S108). For example, the scan control function 55 instructs the X-ray high voltage apparatus 14 and the control apparatus 18 to image the subject P from two directions with the top 33 fixed. The two directions are, for example, the X direction and the Y direction in FIG.

  Next, the system control function 51 receives a scan plan setting input to the input interface 43 while displaying a scanogram on the display 42 (step S110). For example, the system control function 51 receives a scan position setting and a tilt angle setting input of the gantry device 10.

  Next, the system control function 51 instructs the scan control function 55 to execute scanning (step S112). When the scan is completed, the processing of this flowchart ends.

[Error control]
Hereinafter, error control will be described. The error control is executed while the scan is executed, for example, by the cooperation of the error detection function 14A of the X-ray high voltage apparatus 14, the specific function 18A of the control apparatus 18, and the scan control function 55. In the above configuration, various errors (abnormalities) may occur in the X-ray irradiation by the X-ray tube 11. Errors include abnormal discharge (also called Spitz) and instantaneous stop due to momentary power failure. If these errors occur, the accuracy of the detection data (view) acquired during the error will be insufficient, and if this is used directly in the reconstruction process, certain artifacts may occur in the cross-sectional image. There is sex. On the other hand, it is also assumed that a view in which an error has occurred is corrected based on detection results that are adjacent in terms of time or position, but depending on the degree of error, there may be a possibility that correction cannot be performed sufficiently. Therefore, the X-ray CT apparatus 1 of the embodiment performs error control as follows.

  A sensor for detecting the voltage, current, temperature, etc. of the X-ray tube 11 is connected to the error detection function 14A. The error detection function 14 </ b> A refers to the output value of the sensor, and, for example, an error occurs in X-ray irradiation by the X-ray tube 11 based on a temporal change in the voltage of the X-ray tube 11 or the current flowing in the X-ray tube 11. Detect what happened. For example, the error detection function 14A detects that an error has occurred when the amount of change in voltage or current per predetermined time is greater than or equal to a predetermined value. When the error detection function 14A detects that an error has occurred, the error detection function 14A outputs an error notification signal to the specific function 18A.

  The identification function 18A collates the period in which the error notification signal is received with the rotation angle of the rotating frame 17 (in other words, the rotation angle of the X-ray tube 11), and specifies a view when an error occurs. Since the view corresponds to the rotation angle of the X-ray tube 11, such processing is nothing but processing for specifying the range of the rotation angle of the X-ray tube 11 when an error occurs. The specific function 18A outputs information (for example, a view number) indicating a view when an error occurs to the scan control function 55. The specific function 18A is an example of a “specific part”.

  The specific function 18A may be a function of the X-ray high voltage device 14. In this case, the control device 18 provides the X-ray high voltage device 14 with information on the rotation angle of the X-ray tube 11 at any time or in response to a request from the X-ray high voltage device 14. The X-ray high-voltage device 14 specifies a view when an error has occurred based on the timing at which the error detection function 14A has detected that an error has occurred and the rotation angle information provided from the control device 18. For example, the view number is output to the scan control function 55.

  When the scan control function 55 acquires the view number when the error occurs, the scan control function 55 specifies the rotation angle of the X-ray tube 11 corresponding to the view number. Then, after an error has occurred, (1) the X-ray tube 11 is continuously irradiated with X-rays, and (2) the rotation angle at which a normal (non-error) view (detection data) has already been acquired is obtained. X-ray irradiation to the X-ray tube 11 is stopped in the range of (3), and after stopping (3), the X-ray tube 11 is irradiated with X-rays in the range of the rotation angle of the X-ray tube 11 when an error occurs. Let it be done.

  FIG. 3 is a diagram for explaining the contents of processing by the scan control function 55. In the figure, large arrows indicate the progress of scanning. In the example of FIG. 3, the scan is started in a state where the rotation angle of the X-ray tube 11 is at the first rotation angle, and an error is detected from the second rotation angle to the third rotation angle. In this case, the scan control function 55 causes the X-ray tube 11 to continue irradiation with X-rays until the X-ray tube 11 rotates once and the rotation angle reaches the first rotation angle. Next, the scan control function 55 stops the X-ray irradiation on the X-ray tube 11 from the first rotation angle to the second rotation angle at which a normal view (detection data) has already been acquired, and then The X-ray tube 11 is irradiated with X-rays from the second rotation angle to the third rotation angle. In the example of FIG. 3, the rotating frame 17 rotates clockwise, but may rotate counterclockwise.

  Hereinafter, the comparison with the comparative example will be described. FIG. 4 is a diagram for explaining the contents of processing by the apparatus of the comparative example. In the example of FIG. 4, the rotation angle of the X-ray tube 11 in which an error is detected is in the range from the second rotation angle to the third rotation angle, as in the example of FIG. 3. In this case, in the apparatus of the comparative example, the X-ray tube 11 is stopped from being irradiated with X-rays until the first rotation angle is reached from the third rotation angle until the first rotation angle is reached, and the second rotation angle is reached. After reaching the angle, the X-ray tube 11 is restarted to emit X-rays. In this case, if the X-ray tube 11 does not rotate twice, the scan is not completed, and it takes time as compared with the control of the embodiment. If the X-ray tube 11 is scanned for two rotations without stopping the X-ray irradiation, a normal view (detection data) can be acquired. In this case, the X-ray exposure increases. End up. From these, according to the X-ray CT apparatus 1 of the embodiment, when supplementing the view (detection data) in the period in which the error has occurred, the scan can be completed quickly while reducing the exposure by X-rays. .

  The scan control function 55 may switch whether to execute error control depending on the operation mode of the X-ray CT apparatus 1. FIG. 5 is a flowchart (part 1) illustrating an example of a flow of processing executed by the scan control function 55. The process of this flowchart is executed before the scan is started, for example.

  First, the scan control function 55 refers to information input to the input interface 43 before the start of scanning, and determines whether or not the target site is a site with a small motion artifact (step S200). Examples of the region where the motion artifact is large include the heart and the diaphragm. For example, the scan control function 55 refers to the list information of the part with a large motion artifact stored in the memory 41, and when the target part is a part not listed in the list information, the target part is the motion artifact. It is determined that the region has a small area. On the contrary, the list information of the parts with small motion artifacts is stored in the memory 41, and the scan control function 55 determines that the target part is motion artifact when the target part is a part listed in the list information. It may be determined that the region is small. If the target part is not a part with a small motion artifact, the scan control function 55 determines not to perform error control (step S206).

  When it is determined that the target part is a part with a small motion artifact, the scan control function 55 determines whether or not the scan mode to be executed is a helical scan (step S202). If the scan mode to be executed is not helical scan, the scan control function 55 determines to perform error control (step S204). On the other hand, when the scan mode to be executed is helical scan, the scan control function 55 determines not to perform error control (step S206).

  As described above, the scan control function 55 performs error control on the condition that the target part is a part having a small motion artifact. This is because, in a part where the motion artifact is large, it is necessary to perform electrocardiogram synchronous imaging, and thus scanning is often not completed in one rotation, and finer control than the error control described above is required. By such control, the X-ray CT apparatus 1 of the embodiment can perform error control only in necessary scenes.

  The scan control function 55 does not perform error control when the X-ray CT apparatus 1 performs a helical scan. Since the helical scan is a mode in which the subject P is scanned in a spiral shape, it is difficult to suitably apply the error control described above. By such control, the X-ray CT apparatus 1 of the embodiment can perform error control only in necessary scenes.

  FIG. 6 is a flowchart (part 2) illustrating an example of the flow of processing executed by the scan control function 55. The processing of this flowchart chart is started together with the start of scanning after it is determined to perform error control. It is assumed that the rotation angle of the X-ray tube 11 at the start is the first rotation angle.

  First, the scan control function 55 determines whether or not there is a notification of a view number when an error occurs from the specific function 18A (step S300). When there is no notification of the view number when an error occurs, the scan control function 55 determines whether or not the rotation angle of the X-ray tube 11 has reached the first rotation angle (step S302). When it is determined that the rotation angle of the X-ray tube 11 has reached the first rotation angle, the scan control function 55 ends the process of this flowchart and completes the scan.

  If it is determined that the view number is notified when an error occurs, the scan control function 55 determines whether or not the rotation angle of the X-ray tube 11 has reached the first rotation angle (step S304). When it is determined that the rotation angle of the X-ray tube 11 has reached the first rotation angle, the scan control function 55 instructs the X-ray high voltage apparatus 14 to stop the X-ray irradiation of the X-ray tube 11 ( Step S306). In the notification, it is assumed that the content indicating that there was an error within the range of the rotation angle of the X-ray tube 11 from the second rotation angle to the third rotation angle is notified.

  Next, the scan control function 55 determines whether or not the rotation angle of the X-ray tube 11 has reached the second rotation angle (step S308). When it is determined that the rotation angle of the X-ray tube 11 has reached the second rotation angle, the scan control function 55 instructs the X-ray high voltage apparatus 14 to restart the X-ray irradiation of the X-ray tube 11 ( Step S310).

  Next, the scan control function 55 determines whether or not the rotation angle of the X-ray tube 11 has reached the third rotation angle (step S312). When it is determined that the rotation angle of the X-ray tube 11 has reached the third rotation angle, the scan control function 55 ends the process of this flowchart and completes the scan.

  In the above embodiment, at least the specific function 18A and the scan control function are combined as an example of the “X-ray tube control device”.

  In the above-described embodiment, error control at the time of full scan has been described. However, error control can be similarly applied to half scan.

  According to at least one embodiment described above, the X-ray tube 11 is supported by the rotating frame 17 and emits X-rays toward the center of rotation while rotating, and the X-ray tube 11 irradiates and passes through the subject. The X-ray detector 15 for detecting the intensity of the X-ray and the X-ray irradiation by the X-ray tube 11 is detected to detect an error, and the range of the rotation angle of the X-ray tube 11 when the error occurs is determined. When the specifying function 18A and the range of the rotation angle of the X-ray tube 11 when an error occurs are specified by the specifying function 18A, the X-ray tube 11 is continuously irradiated with X-rays, Rotation of the X-ray tube 11 when an error occurs after stopping the X-ray irradiation to the X-ray tube 11 within the rotation angle range in which detection data that is not an error has already been acquired by the X-ray detector 15. X-ray over a range of angles And a scan control function 55 that performs error control that causes X-ray irradiation to be performed, so that when the detection data in the period in which the error has occurred is complemented, the X-ray exposure can be reduced and the scan performed promptly. Can be completed.

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

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 10 Mounting apparatus 11 X-ray tube 14 X-ray high voltage apparatus 14A Error detection function 15 X-ray detector 16 DAS
17 Rotating frame 18 Control device 18A Specific function 40 Console device 50 Processing circuit 55 Scan control function

Claims (4)

An X-ray tube that is supported by a rotating frame and emits X-rays toward the center of rotation while rotating;
An X-ray detector that detects the intensity of X-rays irradiated by the X-ray tube and passed through the subject;
A detection unit that detects that an error has occurred in X-ray irradiation by the X-ray tube, and specifies a range of a rotation angle of the X-ray tube when the error occurs;
When the range of the rotation angle of the X-ray tube when the error occurs is specified by the specifying unit,
Continue X-ray irradiation on the X-ray tube,
After the continuation, X-ray irradiation to the X-ray tube is stopped in a range of rotation angles at which detection data that is not error is already acquired by the X-ray detector,
After the stop, the X-ray tube is irradiated with X-rays in the range of the rotation angle of the X-ray tube when the error occurs.
A control unit that performs error control;
An X-ray CT apparatus comprising: A reception unit that receives an input of information on a target portion that irradiates the X-ray and collects the detection data;
The control unit performs the error control when the target part is a part where the influence of motion artifact is small.
The X-ray CT apparatus according to claim 1. The control unit does not perform the error control when the X-ray CT apparatus performs a helical scan.
The X-ray CT apparatus according to claim 1. An X-ray tube that is supported by a rotating frame and irradiates X-rays toward the center of rotation while rotating, and an X-ray detector that detects the intensity of X-rays irradiated by the X-ray tube and passed through the subject. In the X-ray CT apparatus having, a specifying unit that detects that an error has occurred in X-ray irradiation by the X-ray tube, and specifies a range of a rotation angle of the X-ray tube when the error occurs;
When the range of the rotation angle of the X-ray tube when the error occurs is specified by the specifying unit,
Continue X-ray irradiation on the X-ray tube,
After the continuation, X-ray irradiation to the X-ray tube is stopped in the range of the rotation angle at which detection data that is not an error has already been acquired by the X-ray detector,
A control unit that performs error control to cause the X-ray tube to perform X-ray irradiation in a range of a rotation angle of the X-ray tube when the error occurs after the stop;
An X-ray tube control device.

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