JP2017202304A - X-ray CT apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus capable of assisting proper positioning of a subject on a table top in consideration of vibration occurring at the table top.SOLUTION: An X-ray CT apparatus according to an embodiment includes an X-ray tube, a detector, a table top, a movement control part, and a display control part. The X-ray tube generates an X-ray. The detector detects the X-ray. On the table top, a subject is placed. The movement control part controls a moving mechanism to move the table top in a longitudinal direction. The display control part displays information indicating the magnitude of a vibration that occurs, when each position in the longitudinal direction on the table top is moved to a position intersecting a path of the X-ray, at the position.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an X-ray CT (Computed Tomography) apparatus.

  Conventionally, an X-ray CT apparatus includes a top plate on which a subject is placed, and moves the top plate on a moving path that intersects the X-ray path from the X-ray tube to the detector. When the subject is imaged, the X-ray CT apparatus moves the top plate on which the subject is placed to an imaging position where the region to be imaged intersects the X-ray.

  In such an X-ray CT apparatus, when the top plate is moved, vibration may occur at each position on the top plate due to, for example, the top plate and a mechanical structure around the top plate. Then, when shooting is performed in a state where vibration is generated in a portion to be shot, the image quality of the shot image may be deteriorated.

JP 2009-268799 A JP 2010-269066 A JP 2009-000209 A Japanese Patent Publication No. 03-064998 JP 2007-136229 A JP 2014-0664900 A JP 2008-220647 A JP 2005-245663 A

  The problem to be solved by the present invention is to provide an X-ray CT apparatus capable of supporting appropriate positioning of a subject on the top board in consideration of vibrations generated on the top board.

  The X-ray CT apparatus according to the embodiment includes an X-ray tube, a detector, a top plate, a movement control unit, and a display control unit. The X-ray tube generates X-rays. The detector detects the X-ray. A subject is placed on the top board. The movement control unit controls a moving mechanism for moving the top plate in the longitudinal direction. The display control unit displays information indicating the magnitude of vibration generated at each position when each position in the longitudinal direction on the top plate is moved to a position intersecting the X-ray path.

FIG. 1 is a diagram illustrating a configuration example of an X-ray CT apparatus according to the present embodiment. FIG. 2 is a diagram illustrating movement of the top board by the movement control function according to the present embodiment. FIG. 3 is a diagram illustrating an example of vibration generated at each position on the top plate according to the present embodiment. FIG. 4 is a diagram illustrating an example of information displayed by the display control function according to the present embodiment. FIG. 5 is a diagram illustrating an example of vibration information stored by the storage circuit according to the present embodiment. FIG. 6 is a diagram illustrating an example of decay time information stored by the storage circuit according to the present embodiment. FIG. 7 is a flowchart illustrating a processing procedure of processing performed by the display control function and the imaging control function according to the present embodiment. FIG. 8 is a diagram illustrating an example of display of a simulated image by the display control function according to the present embodiment. FIG. 9 is a diagram illustrating an example of display of a simulated image by the display control function according to the present embodiment. FIG. 10 is a diagram illustrating an example of a scanano image display by the display control function according to the present embodiment. FIG. 11 is a diagram showing an example of a scanogram display by the display control function according to the present embodiment. FIG. 12 is a flowchart illustrating a processing procedure of main photographing performed by the photographing control function according to the present embodiment.

  Hereinafter, an embodiment of an X-ray CT apparatus according to the present application will be described in detail with reference to the accompanying drawings. The embodiment described below is an example, and the X-ray CT apparatus according to the present application is not limited to the following embodiment.

  FIG. 1 is a diagram illustrating a configuration example of an X-ray CT apparatus according to the present embodiment. For example, as shown in FIG. 1, the X-ray CT apparatus 100 according to the present embodiment includes a gantry 10, a bed 20, and a console 30.

  The gantry 10 is a device that irradiates the subject S (patient) with X-rays, detects the X-rays transmitted through the subject S, and outputs them to the console 30. For example, the gantry 10 includes an X-ray irradiation control circuit 11, an X-ray generator 12, a detector 13, a data acquisition circuit (DAS: Data Acquisition System) 14, a rotating frame 15, a gantry driving circuit 16, And a projector 17.

  The X-ray generator 12 generates X-rays and irradiates the subject S with the generated X-rays. For example, the X-ray generator 12 includes an X-ray tube 12a, a wedge 12b, and a collimator 12c.

  The X-ray tube 12a generates X-rays. For example, the X-ray tube 12a is a vacuum tube and generates X-rays by a high voltage supplied from a high voltage generator (not shown). The X-ray tube 12a generates X-rays that spread with a fan angle and a cone angle.

  The wedge 12b is an X-ray filter for adjusting the X-ray dose of X-rays emitted from the X-ray tube 12a. Specifically, the wedge 12b transmits and attenuates the X-rays emitted from the X-ray tube 12a so that the X-rays irradiated from the X-ray tube 12a to the subject S have a predetermined distribution. It is a filter to do. For example, the wedge 12b is a filter obtained by processing aluminum so as to have a predetermined target angle or a predetermined thickness. The wedge is also called a wedge filter or a bow-tie filter.

  The collimator 12c is a slit for narrowing the X-ray irradiation range in which the X-ray dose is adjusted by the wedge 12b under the control of the X-ray irradiation control circuit 11 described later.

  The X-ray irradiation control circuit 11 controls the X-ray generator 12 under the control of a scan control circuit 33 described later. For example, the X-ray irradiation control circuit 11 controls a high voltage generator (not shown) and supplies a high voltage to the X-ray tube 12 a included in the X-ray generator 12. The X-ray irradiation control circuit 11 adjusts the X-ray dose irradiated to the subject S by adjusting the tube voltage and tube current supplied to the X-ray tube 12a. Further, the X-ray irradiation control circuit 11 switches the wedge 12b included in the X-ray generator 12. The X-ray irradiation control circuit 11 adjusts the X-ray irradiation range (fan angle and cone angle) by adjusting the aperture of the collimator 12 c included in the X-ray generator 12.

  The detector 13 detects X-rays generated from the X-ray tube 12a. For example, the detector 13 is a two-dimensional array type detector (surface detector) that detects X-rays that have passed through the subject S, and a detection element array in which X-ray detection elements for a plurality of channels are arranged. A plurality of rows are arranged along the body axis direction of the sample S (Z-axis direction shown in FIG. 1). Specifically, the detector 13 in the present embodiment includes X-ray detection elements arranged in multiple rows such as 320 rows along the body axis direction of the subject S. For example, the lungs or heart of the subject S It is possible to detect X-rays that have passed through the subject S over a wide range, such as a range including.

  The rotating frame 15 is an annular frame and supports the X-ray generator 12 and the detector 13 so as to face each other with the subject S interposed therebetween.

  The gantry driving circuit 16 rotates the rotating frame 15 under the control of the scan control circuit 33 described later, thereby causing the X-ray generator 12 and the detector 13 to move on a circular orbit around the subject S. Turn.

  The data collection circuit 14 collects projection data from X-ray detection data detected by the detector 13 under the control of a scan control circuit 33 described later. The data acquisition circuit 14 is also called DAS (Data Acquisition System). For example, the data collection circuit 14 generates projection data by performing amplification processing, A / D conversion processing, inter-channel sensitivity correction processing, and the like on the X-ray intensity distribution data detected by the detector 13. The projected data is transmitted to the console 30 described later. Note that the sensitivity correction processing between channels may be performed by the preprocessing circuit 34 described later.

  The projector 17 irradiates the top plate 21 on which the subject S is placed with visible light (laser light). For example, the projector 17 is provided in the upper part of the opening part in which the top plate 21 is inserted formed in the mount 10, and irradiates visible light toward the lower side. The position irradiated with visible light on the top plate 21 appears brighter than other positions. For example, the position irradiated with visible light on the top 21 is used as a positioning reference when the subject S is placed on the top 21.

  The bed 20 is a device on which the subject S is placed, and includes a top plate 21 on which the subject S is placed and a bed driving device 22 as shown in FIG. The bed driving device 22 moves the subject S into the rotary frame 15 by moving the top plate 21 in the Z-axis direction. That is, the bed driving device 22 is an example of a moving mechanism for moving the top plate 21 in the longitudinal direction.

  For example, the gantry 10 performs a helical scan that rotates the rotating frame 15 while continuously moving the top plate 21 to scan the subject S in a spiral shape. Alternatively, the gantry 10 performs a conventional scan in which the subject S is scanned in a circular orbit by rotating the rotating frame 15 while the position of the subject S is fixed after the top plate 21 is moved. Alternatively, the gantry 10 executes a step-and-shoot method in which the position of the top plate 21 is moved at regular intervals and a conventional scan is performed at a plurality of imaging positions.

  The console 30 is a device that accepts an operation of the X-ray CT apparatus 100 by an operator and reconstructs CT image data using projection data collected by the gantry 10. As shown in FIG. 1, the console 30 includes an input circuit 31, a display 32, a scan control circuit 33, a preprocessing circuit 34, a storage circuit 35, an image reconstruction circuit 36, and a processing circuit 37. .

  The input circuit 31 includes a mouse, a keyboard, a trackball, a switch, a button, a joystick, and the like that are used by the operator of the X-ray CT apparatus 100 to input various instructions and various settings, and instructions and setting information received from the operator. Is transferred to the processing circuit 37. For example, the input circuit 31 receives, from the operator, imaging conditions for CT image data, reconstruction conditions for reconstructing CT image data, image processing conditions for CT image data, and the like. The input circuit 31 accepts a designation operation for designating a predetermined region such as a region on the image or a region of interest.

  The display 32 is a monitor that is referred to by the operator, displays a CT image generated from the CT image data to the operator under the control of the processing circuit 37, and displays various CT images from the operator via the input circuit 31. A GUI (Graphical User Interface) for receiving instructions and various settings is displayed.

  The scan control circuit 33 controls the operations of the X-ray irradiation control circuit 11, the gantry driving circuit 16, the data collection circuit 14, and the bed driving device 22 under the control of the processing circuit 37, thereby Control the collection process. For example, the scan control circuit 33 performs control so as to execute photographing for collecting a scanogram used for positioning of a photographing region photographed in actual photographing. That is, the scanogram is an example of a subject positioning image. In addition, for example, the scan control circuit 33 controls projection data collection processing in main imaging for collecting images used for diagnosis.

  For example, the scan control circuit 33 fixes the X-ray tube 12a at a position of 0 degree (a position in the front direction with respect to the subject S) and continuously performs imaging while moving the top plate 21 at a constant speed. Take a two-dimensional scano image with. Alternatively, the scan control circuit 33 fixes the X-ray tube 12a at a position of 0 degree and moves the top plate 21 intermittently, while repeating the imaging intermittently in synchronization with the top plate movement. Take a scano image. Here, the scan control circuit 33 can capture a scanogram from an arbitrary direction (for example, a side surface direction) as well as the front direction with respect to the subject S.

  The preprocessing circuit 34 performs logarithmic conversion processing and correction processing such as offset correction, sensitivity correction, and beam hardening correction on the projection data generated by the data acquisition circuit 14 to obtain corrected projection data. Generate. Specifically, the preprocessing circuit 34 generates corrected projection data for each of the projection data of the scano image generated by the data acquisition circuit 14 and the projection data acquired by the main photographing, and the storage circuit 35. To store.

  The storage circuit 35 stores the projection data generated by the preprocessing circuit 34. Specifically, the storage circuit 35 stores the scan data of the scanogram and the projection data for diagnosis collected by the main imaging, which are generated by the preprocessing circuit 34. The storage circuit 35 stores a CT image generated by an image reconstruction circuit 36 described later. Further, the storage circuit 35 appropriately stores a processing result by a processing circuit 37 described later.

  The image reconstruction circuit 36 reconstructs CT image data using the projection data stored in the storage circuit 35. Specifically, the image reconstruction circuit 36 reconstructs the CT image data from the scan data of the scanogram and the projection data of the image used for diagnosis. Here, as the reconstruction method, there are various methods, for example, back projection processing. Further, as the back projection process, for example, a back projection process by an FBP (Filtered Back Projection) method can be cited. Alternatively, the image reconstruction circuit 36 can reconstruct CT image data using a successive approximation method. Further, the image reconstruction circuit 36 performs various image processing on the CT image data to generate various CT images. Then, the image reconstruction circuit 36 stores the reconstructed CT image data and CT images generated by various image processes in the storage circuit 35.

  The processing circuit 37 performs overall control of the X-ray CT apparatus 100 by controlling the operations of the gantry 10, the bed 20, and the console 30. Specifically, the processing circuit 37 controls the CT scan performed on the gantry 10 by controlling the scan control circuit 33. The processing circuit 37 controls the image reconstruction circuit 36 and the image generation process in the console 30 by controlling the image reconstruction circuit 36. Further, the processing circuit 37 controls the display 32 to display various CT images stored in the storage circuit 35.

  The overall configuration of the X-ray CT apparatus 100 according to the present embodiment has been described above.

  Here, in such an X-ray CT apparatus 100, when the top plate 21 is moved, vibrations are generated at each position on the top plate 21 due to, for example, the top plate 21 and the mechanical structure around the top plate 21. May occur. Then, when shooting is performed in a state where vibration is generated in a portion to be shot, the image quality of the shot image may be deteriorated.

  In general, a bed provided in an X-ray CT apparatus has a cantilever structure that supports one end of a top plate on which a subject is placed. The contact state between the fulcrum and the top plate changes depending on the distance and the deflection of the top plate. In the contact state between the fulcrum and the top plate, there is an inflection point at which the balance is changed, and it is considered that the vibration of the top plate increases when passing through the inflection point. And when imaging is performed in a state where the position where the imaging target part is placed on the top plate is vibrating, the image quality of the captured image may be degraded.

  For this reason, the X-ray CT apparatus 100 according to the present embodiment is configured to support appropriate positioning of the subject on the top board in consideration of vibrations generated on the top board. Hereinafter, the configuration of such an X-ray CT apparatus 100 will be described in more detail.

  For example, as illustrated in FIG. 1, the processing circuit 37 includes a movement control function 37a, a display control function 37b, and a photographing control function 37c. The movement control function 37a is an example of a movement control unit described in the claims. The display control function 37b is an example of a display control unit described in the claims. The imaging control function 37c is an example of an imaging control unit described in the claims.

  Here, for example, the processing circuit 37 is realized by a processor. Further, for example, the processing functions of the movement control function 37a, the display control function 37b, and the photographing control function 37c are recorded in the storage circuit 35 in the form of a program that can be executed by a computer. Then, the processing circuit 37 reads out each program from the storage circuit 35 and executes it, thereby realizing a function corresponding to each program. In other words, the processing circuit 37 in a state where each program is read has each function shown in the processing circuit 37 of FIG.

  The movement control function 37 a moves the top plate 21 on a movement path that intersects the X-ray path from the X-ray tube 12 a to the detector 13. Specifically, the movement control function 37a controls the couch driving device 22 to move the top board 21 on the movement path. That is, the movement control function 37a controls a moving mechanism for moving the top board 21 in the longitudinal direction.

  FIG. 2 is a diagram illustrating movement of the top board 21 by the movement control function 37a according to the present embodiment. For example, as shown in FIG. 2, the movement control function 37 a has a direction from the bed 20 toward the gantry 10 on the movement path R passing between the X-ray tube 12 a provided on the gantry 10 and the detector 13, and The top plate 21 is moved in the direction from the gantry 10 to the bed 20. Here, for example, the movement path R is set to be orthogonal to the X-ray path P from the center of the X-ray tube 12 a toward the center of the detector 13 at a position I on the movement path R.

  As described above, when the top plate 21 is moved, vibration may occur at each position on the top plate 21 due to, for example, the top plate 21 and the mechanical structure around the top plate 21. .

  FIG. 3 is a diagram illustrating an example of vibration generated at each position on the top plate 21 according to the present embodiment. Here, the figure shown on the upper side of FIG. 3 shows the magnitude of vibration generated in the top plate 21 when the top plate 21 is continuously moved in the direction from the bed 20 toward the gantry 10. In the figure shown in the upper side of FIG. 3, the horizontal axis indicates each position when the position of the tip of the top plate 21 is zero, and the vertical axis indicates the position I shown in FIG. The amplitude of the vibration generated at each position is shown. Moreover, the figure shown in the lower side of FIG. 3 shows a state in which the top plate 21 is viewed from above, and shows the position in the longitudinal direction in alignment with the position of the horizontal axis in the figure shown in the upper side.

  For example, as shown in FIG. 3, when the top plate 21 is continuously moved in the direction from the bed 20 toward the gantry 10, a large vibration is generated at some positions on the top plate 21 compared to other positions. May occur. FIG. 3 shows an example in which a maximum vibration occurs in the vicinity of the center of the top plate 21 in the longitudinal direction. As described above, when a part to be photographed is placed at a position where a large vibration is generated on the top plate 21, the image quality of the photographed image may be deteriorated.

  Returning to FIG. 1, the display control function 37 b is information indicating the magnitude of vibration generated at each position when each position on the top plate 21 is moved to a position that intersects the X-ray path on the movement path. Is displayed. That is, the display control function 37b displays information indicating the magnitude of vibration generated at each position when each position in the longitudinal direction on the top plate 21 is moved to a position that intersects the X-ray path. Specifically, the display control function 37b displays information indicating the magnitude of the vibration on the display 32.

  For example, the display control function 37b displays a top board image representing the shape of the top board 21, and displays information indicating the magnitude of vibration in association with each position on the top board image. That is, the top board image is an example of a simulated image of the top board 21.

  FIG. 4 is a diagram illustrating an example of information displayed by the display control function 37b according to the present embodiment. FIG. 4 shows the same example as FIG. For example, as shown in the lower side of FIG. 4, the display control function 37 b displays a top board image 40 representing the shape of the top board 21. For example, the display control function 37b adds a different color to the top board image 40 according to the magnitude of vibration generated at each position on the top board 21.

  For example, as shown in FIG. 4, the display control function 37b divides the amplitude of vibration generated at each position on the top board 21 into three ranges using two threshold values T1 and T2 (T1> T2). For example, the display control function 37b sets a range where amplitude ≧ T1 is “large vibration”, a range where T1> amplitude ≧ T2 is “in vibration”, and a range where amplitude <T2 is “small vibration”. The display control function 37b adds a different color to the top image 40 for each range of vibration.

  Here, an example in which the amplitude is divided into three ranges has been described, but the embodiment is not limited thereto. For example, the display control function 37b may divide the amplitude into four or more ranges, or may color each position according to the magnitude of the amplitude. In addition, the display control function 37b may have different patterns instead of different colors depending on the amplitude.

  In this way, the display control function 37b displays information indicating the magnitude of vibration generated at each position when each position on the top plate 21 is moved to a position that intersects the X-ray path. When a radiographer or the like places the subject on the top plate 21, the subject can be positioned so that the region to be imaged is placed at a position where vibration is small by referring to the displayed information. .

  As described above, the display control function 37 b displays information indicating the magnitude of vibration in association with the simulated image of the top board 21.

  In addition, the display control function 37b displays information indicating the magnitude of vibration that occurs when imaging is performed based on the imaging condition, according to the imaging condition.

  For example, the display control function 37b displays information indicating the magnitude of vibration that occurs when the subject having the weight is placed on the top board 21 according to the weight of the subject.

  Specifically, for example, the display control function 37b displays information indicating the magnitude of the vibration based on the actual measurement result obtained by actually measuring the vibration by moving the top plate 21 while changing the weight of the subject. In this case, for example, as shown in FIG. 3, the storage circuit 35 is positioned on the top plate 21 at each position when the position of the tip of the top plate 21 is zero and at the position I shown in FIG. Information that associates the magnitude of the amplitude of vibration generated at each position is stored for each weight of the subject.

  FIG. 5 is a diagram illustrating an example of vibration information stored by the storage circuit 35 according to the present embodiment. For example, as shown in FIG. 5, the storage circuit 35 stores each position (position 1, position 2, position 3) on the top 21 for each body weight (body weight 1, body weight 2, body weight 3,...). ,..., And the magnitudes of the amplitudes of the vibrations generated at the respective positions (amplitude 11, amplitude 12, amplitude 13,...) Are stored. This information is generated based on the actual measurement result and stored in the storage circuit 35 before the use of the X-ray CT apparatus 100 is started (for example, at the time of shipment or installation of the X-ray CT apparatus 100). .

  The display control function 37b refers to the vibration information stored in the storage circuit 35 and acquires information corresponding to the weight of the subject set as part of the imaging conditions. And the display control function 37b displays the information which shows the magnitude | size of the vibration which arises in each position on the top plate 21 based on the acquired information.

  For example, when the relationship between the weight of the subject and the amplitude of vibration generated at each position of the top 21 can be defined as a function, the display control function 37b uses the function to You may derive | lead-out the magnitude | size of the vibration which arises in each position of the board 21. FIG. In this case, the display control function 37b calculates the amplitude of vibration generated at each position on the top board 21 from the weight of the subject set as a part of the imaging conditions, using the function. And the display control function 37b displays the information which shows the magnitude | size of the vibration which arises in each position on the top plate 21 based on the calculated result.

  In this way, the display control function 37b displays information indicating the magnitude of vibration generated when the subject having the weight is placed on the top board 21 according to the weight of the subject, thereby Even when the vibration generated in the top plate 21 fluctuates due to the weight of the subject, the subject can be positioned more appropriately according to the individual subject.

  2 to 5 show an example in which the X-ray path is a straight path from the center of the X-ray tube 12a to the center of the detector 13, the embodiment is not limited thereto.

  Usually, the X-rays exposed from the X-ray tube 12a spread radially and enter the detector 13. Therefore, for example, the X-ray path may be a path having a width in the longitudinal direction of the top plate 21.

  In this case, for example, the display control function 37b uses the longitudinal length within the range where the top plate 21 and the X-ray path intersect as information indicating the magnitude of vibration occurring at each position in the longitudinal direction on the top plate 21. Information indicating the average value of the magnitude of vibration generated at each position in the direction is displayed. The average value displayed here is obtained when each position on the top plate 21 is moved to the center position in the longitudinal direction in the range where the top plate 21 and the X-ray path intersect. It is an average value of the magnitude of vibration generated at the position.

  In this case, the storage circuit 35 stores information in which each position in the longitudinal direction on the top plate 21 is associated with the above-described average value for each weight of the subject.

  In addition, for example, the display control function 37b displays information indicating the magnitude of vibration according to the imaging condition relating to the orientation of the subject in the longitudinal direction when the subject is placed on the top 21. Also good.

  For example, the imaging conditions relating to the orientation of the subject referred to here include the direction in which the subject is inserted when the subject is inserted into the opening of the gantry 10. For example, “head first” indicating that the subject is inserted from the head into the opening of the gantry 10 as the direction of insertion of the subject, or the subject is inserted from the foot into the opening of the gantry 10 “Foot First” is set. Here, since the arrangement of the subject on the top 21 changes between when head-first imaging is performed and when foot-first imaging is performed, the magnitude of vibration generated on the top 21 changes. Conceivable.

  Further, for example, as an imaging condition related to the direction of the subject, there is whether or not an accessory attached to the end of the top plate 21 in the longitudinal direction is used. For example, depending on the position of the region to be imaged and the height of the subject, the head or foot of the subject may protrude from the top plate 21. Accessories such as a headrest for supporting the head and a footrest for supporting the foot may be attached to the part. Here, when the accessory is attached to the top plate 21, the arrangement of the subject on the top plate 21 changes compared to the case where the accessory is not used. Is considered to fluctuate.

  As described above, it is considered that the magnitude of the vibration generated in the top plate 21 varies depending on the imaging conditions related to the direction of the subject.

  Therefore, for example, the display control function 37b displays information indicating the magnitude of the vibration based on the actual measurement result obtained by actually measuring the vibration of the top board 21 while changing the imaging condition related to the direction of the subject. In this case, for example, as shown in FIG. 3, the storage circuit 35 is positioned on the top plate 21 at each position when the position of the tip of the top plate 21 is zero and at the position I shown in FIG. Information that associates the magnitude of the vibration amplitude generated at each position is stored for each imaging condition related to the orientation of the subject.

  For example, the memory circuit 35 is head first and foot first when a head rest is used, and head first when a foot rest is used and foot first when a foot rest is used. When the headrest is used, the head first and the accessory are not used, and the foot first and the accessory are not used. Stores information associating positions (position 1, position 2, position 3,...) With amplitudes of vibrations generated at the respective positions (amplitude 11, amplitude 12, amplitude 13,...). To do. As in the case of storing information for each body weight of the subject, this information is used before the use of the X-ray CT apparatus 100 is started (for example, at the time of shipment or installation of the X-ray CT apparatus 100). Are generated in advance based on the actual measurement results and stored in the storage circuit 35.

  Then, the display control function 37b refers to the vibration information stored in the storage circuit 35 and acquires information related to the orientation of the subject set as part of the imaging conditions. And the display control function 37b displays the information which shows the magnitude | size of the vibration which arises in each position on the top plate 21 based on the acquired information. In this case as well, as in the case of displaying information according to the weight of the subject, the display control function 37b derives the magnitude of vibration generated at each position of the top board 21 using a function. Also good.

  Furthermore, for example, the display control function 37b may display information indicating the magnitude of vibration according to both the body weight of the subject and the imaging conditions related to the orientation of the subject. In this case, the storage circuit 35 stores the information for each body weight illustrated in FIG. 5 for each imaging condition related to the direction of the subject.

  In this way, the display control function 37b displays information indicating the magnitude of vibration that occurs when imaging is performed based on the imaging conditions in accordance with the imaging conditions, so that the top plate 21 can be changed according to the imaging conditions. Even when the generated vibration fluctuates, the subject can be positioned more appropriately.

  For example, the display control function 37b further aligns and displays a subject image representing the shape of the subject including the region to be imaged on the top image. For example, when the subject is placed on the top 21 by a radiographer or the like, the display control function 37b captures the subject image at a position where the magnitude of vibration is less than a predetermined value on the top 21 as the subject image. A simulated image representing the shape of the subject in a simulated manner is displayed so that the region is arranged. Further, for example, the display control function 37b displays a scano image as a subject image after a scano image of the subject is captured for positioning of the imaging region captured in the main imaging. The display of the subject image performed by the display control function 37b will be described in detail later.

  Returning to FIG. 1, the imaging control function 37c attenuates until the magnitude of the vibration generated at the position where the X-rays on the top 21 cross when the top 21 is moved to the imaging position becomes a predetermined value or less. Time is derived and imaging is controlled based on the decay time. Specifically, the imaging control function 37c starts the imaging by controlling the scan control circuit 33 and the movement control function 37a.

  For example, the imaging control function 37c moves the top plate 21 while changing the height of the top plate 21, the feed amount of the top plate 21, the weight of the subject, and the moving speed of the top plate 21, and sets the vibration decay time. The photographing is controlled based on the actually measured result. In this case, for example, the storage circuit 35 has the top 21 at the height I, the top 21 feed amount, the weight of the subject, the moving speed of the top 21, and the position I shown in FIG. Information that associates the decay time until the amplitude of vibration generated at each position on the plate 21 becomes a predetermined value or less is stored.

  FIG. 6 is a diagram illustrating an example of decay time information stored by the storage circuit 35 according to the present embodiment. For example, as shown in FIG. 6, the height of the top plate 21 (height 1, height 2, height 3,...), The feed amount of the top plate 21 (feed amount 1, feed amount 2, feed amount). 3,..., The weight of the subject (weight 1, weight 2, weight 3,...), And the movement speed of the table 21 (movement speed 1, movement speed 2, movement speed 3,... ) And the decay time (attenuation time 1, decay time 2, decay time 3,...) Are stored. This information is generated based on the actual measurement result and stored in the storage circuit 35 before the use of the X-ray CT apparatus 100 is started (for example, at the time of shipment or installation of the X-ray CT apparatus 100). .

  For example, the imaging control function 37c controls the moving speed of the top plate 21 so that the sum of the movement time until the top plate 21 is moved to the imaging position and the vibration attenuation time is minimized. First, the imaging control function 37c refers to the information on the decay time stored in the storage circuit 35, and the height of the top plate 21, the feeding amount of the top plate 21 set as part of the imaging conditions, and the subject Get information corresponding to weight. Thereafter, the imaging control function 37c calculates the moving time of the top plate 21 from the feed amount of the top plate 21 and the moving speed of the top plate 21 for each acquired information, and calculates the total of the calculated moving time and decay time. To do. Then, the imaging control function 37c specifies information that minimizes the sum of the calculated movement time and decay time, and instructs the movement control function 37a to move the top board 21 at the specified information movement speed. .

  Note that, for example, the relationship between the height of the top 21, the feed amount of the top 21, the weight of the subject, and the moving speed of the top 21 that minimizes the sum of the travel time and the decay time of the top 21. Can be defined by a function, the display control function 37b may derive the moving speed of the top board 21 using the function. In this case, the display control function 37b uses the function to calculate the top plate 21 from the height of the top plate 21, the feeding amount of the top plate 21, and the weight of the subject set as a part of the imaging conditions. Calculate the moving speed. Then, the display control function 37b instructs the movement control function 37a to move the top board 21 at the calculated movement speed.

  In this way, the imaging control function 37c controls the moving speed of the top plate 21 so that the total of the movement time until the top plate 21 is moved to the imaging position and the vibration attenuation time is minimized. Thus, it is possible to set an optimum shooting time in consideration of vibrations generated on the top plate 21.

For example, the imaging control function 37c starts imaging when the derived decay time has elapsed after the top 21 has been moved to the imaging position. At this time, specifically, the imaging control function 37 c starts the imaging by controlling the scan control circuit 33. Note that the shooting control performed by the shooting control function 37c will be described in detail later.
Hereinafter, processing performed by the display control function 37b and the imaging control function 37c described above will be described in more detail with reference to flowcharts.
FIG. 7 is a flowchart illustrating a processing procedure of processing performed by the display control function 37b and the imaging control function 37c according to the present embodiment.

  For example, as shown in FIG. 7, first, the shooting control function 37c receives input of information regarding shooting conditions from the operator via the input circuit 31, and sets shooting conditions based on the received information (step S1). ). The imaging conditions set here include the body weight of the subject, the height of the subject, the height of the top 21, the feed amount of the top 21, the imaging conditions related to the orientation of the subject, and the like.

  Thereafter, the display control function 37b displays a top plate image 40 representing the shape of the top plate 21 and information indicating the magnitude of vibration occurring at each position of the top plate 21 (step S2). The display control function 37b aligns the simulated image of the subject on the top image 40 so that the part to be imaged is arranged at a position where the magnitude of vibration is less than a predetermined value on the top plate 21. And further display (step S3).

  8 and 9 are diagrams illustrating an example of display of a simulated image by the display control function 37b according to the present embodiment. 8 and 9, as described with reference to FIG. 4, the magnitude of vibration generated at each position on the top plate 21 is divided into three types of “low vibration”, “during vibration”, and “high vibration”. An example in the case of displaying divided into ranges is shown. 8 shows an example in which there is one position where the vibration is maximized on the top plate 21, as shown in FIGS. 3 and 4, and FIG. The example in the case where there are two positions that are maximum is shown.

  Here, FIG. 8A shows an example in which the region to be imaged is the liver and the direction of the subject set as part of the imaging conditions is HF (Head First). In this case, for example, as shown in FIG. 8A, the display control function 37b displays the simulated image 50 so that the head of the subject is arranged on the top side of the top image 40. Further, the display control function 37b aligns and displays the simulated image 50 on the top board image 40 so that the liver portion 51 included in the simulated image 50 of the subject is arranged in the range of “small vibration”. To do. At this time, for example, the display control function 37b arranges the simulated image 50 so that the liver portion 51 is arranged in the range of “small vibration” and is located as close to the center of the top plate 21 as possible. .

  FIG. 8B shows an example in which the region to be imaged is the small intestine and the direction of the subject set as part of the imaging conditions is FF (Foot First). In this case, for example, as shown in FIG. 8B, the display control function 37b displays the simulated image 50 so that the leg of the subject is arranged on the top side of the top image 40. Further, the display control function 37b aligns and displays the simulated image 50 on the top board image 40 so that the small intestine portion 52 included in the simulated image 50 of the subject is arranged in the range of “small vibration”. To do. At this time, for example, as in the example shown in FIG. 8A, the display control function 37b has the small intestine portion 52 arranged in the range of “small vibration” and is as close to the center of the top plate 21 as possible. The simulated image 50 is arranged so as to be arranged at the position.

  As described above, the display control function 37b displays the simulated image 50 of the subject on the top board image 40 so that the part to be imaged is arranged on the top board 21 at a position where the magnitude of vibration is less than the predetermined value. By positioning and displaying the subject, the subject can be positioned more easily so that when the radiographer or the like places the subject on the top plate 21, the region to be imaged is placed at a position where vibration is small. become able to.

  Here, the display control function 37b can identify the part of the subject on the simulated image 50 when the part of the subject protrudes from the top 21 when the simulated image 50 is aligned on the top image 40. To display. For example, as shown in FIG. 8B, when the leg of the subject protrudes from the top board 21, the display control function 37b displays the graphic 60 at the position of the leg.

  In this way, when the display control function 37b displays the portion that protrudes from the top plate 21 so as to be identifiable on the simulated image 50, for example, when the leg of the subject has protruded to the radiologist or the like. Can urge the user to respond to a portion that protrudes from the top plate 21 such as bending a leg portion.

  Further, for example, the display control function 37b displays the simulated image 50 by changing the size according to the height of the subject. For example, FIGS. 9A and 9B show examples in which the region to be imaged is the liver and the direction of the subject set as part of the imaging conditions is HF (Head First). Yes. Here, FIG. 9B shows an example in which the height of the subject is smaller than that in FIG.

  In this case, for example, as shown in FIGS. 9A and 9B, the display control function 37 b has a simulated image 50 so that the head of the subject is arranged on the top side of the top image 40. Is displayed. Further, for example, as shown in FIGS. 9A and 9B, the display control function 37b is within the range where the liver portion 51 is “small vibration”, as in the example shown in FIG. The simulated image 50 is arranged so as to be arranged as close to the center of the top plate 21 as possible.

  For example, as shown in FIGS. 9A and 9B, the display control function 37b changes the size of the simulated image 50 in accordance with the height of the subject set as part of the imaging conditions. To display. Specifically, when the height of the subject is larger than a predetermined reference height, the display control function 37b adjusts the size to the reference height in accordance with the ratio between the height of the subject and the reference height. The created simulated image 50 is enlarged and displayed. On the other hand, when the height of the subject is smaller than the reference height, the display control function 37b displays a simulated image 50 created in a size that matches the reference height in accordance with the ratio between the height of the subject and the reference height. Zoom out and display.

  In this way, the display control function 37b changes the size of the simulated image 50 in accordance with the height of the subject and displays the positional relationship between the subject and the top board 21 to the radiographer or the like. It becomes possible to present more accurately.

  Further, for example, the display control function 37b further displays information indicating a position serving as a reference for positioning the subject when the subject is placed on the top plate 21. For example, as shown in FIG. 8B and FIG. 9B, the display control function 37b is located on the top image 40 at a position corresponding to a mark previously attached to the top 21. A graphic 70 indicating the position of the mark is displayed.

  Here, an example has been described in which the graphic 70 indicating the position of the mark previously attached to the top 21 is displayed as information indicating the position serving as the reference for positioning the subject. Not limited to. For example, the display control function 37b may display a graphic indicating a position where visible light is irradiated on the top plate 21 by the projector 17.

In this way, the display control function 37b displays information indicating the position that serves as a reference for positioning the subject when the subject is placed on the top board 21, so that a radiographer or the like can display the subject. Positioning can be performed more accurately.
As described above, the display control function 37b displays the information indicating the magnitude of the vibration in association with the simulated image that represents the shape of the subject in a simulated manner.

Returning to FIG. 7, after the subject is placed on the top board 21 by a radiographer or the like (step S <b> 4, Yes), the imaging control function 37 c captures a scanogram in accordance with a start instruction from the operator. (Step S5).
Thereafter, the display control function 37b aligns and displays the scanogram of the subject on the top board image 40 (step S6).

  FIGS. 10 and 11 are diagrams showing an example of a scanogram display by the display control function 37b according to the present embodiment. FIGS. 10A and 10B show an example in which a scanogram 80 is displayed on the top image 40 shown in FIGS. 8A and 8B. FIG. (A) and (B) show an example in which a scano image 80 is displayed on the top image 40 shown in (A) and (B) of FIG. Here, in the scanogram 80, a liver 81 and a small intestine 82, which are parts to be imaged, are depicted.

  For example, as shown in FIGS. 10 and 11, the display control function 37 b is a scan image captured based on the positional relationship between the position of the tabletop 21 and the position on the image that is defined in advance using device coordinates or the like. 80 is aligned and displayed on the top board image 40. Accordingly, the scanogram 80 is displayed with the size and orientation appropriately changed for each subject in accordance with the height of the subject and the direction of the subject, similarly to the simulated image 50 shown in FIGS. Will be.

  Here, for example, as shown in FIG. 10B, the display control function 37b also protrudes from the top plate 21 in the same manner as in the example shown in FIG. A graphic 60 indicating the portion of the subject is displayed.

  For example, as shown in FIG. 10B and FIG. 11B, the display control function 37b also displays the scano image 80 in FIG. 8B and FIG. 9B. Similarly to the example shown in FIG. 5, a graphic 70 indicating the position of the mark is displayed on the top image 40 at a position corresponding to a mark previously attached to the top 21.

In this way, the display control function 37b aligns and displays the scan image 80 of the subject imaged for positioning of the imaging region imaged in the main imaging on the top panel image 40, thereby providing a radiographer or the like. However, when the subject is placed on the top plate 21, it can be determined more accurately whether or not the region to be imaged is placed at a position where vibration is small.
As described above, the display control function 37b displays information indicating the magnitude of vibration in association with the positioning image of the subject.

  Returning to FIG. 7, when it is determined by the radiologist or the like that the subject is not properly positioned (No at Step S <b> 7), the imaging control function 37 c responds to the start instruction from the operator. Then, the scano image is captured again (step S5), and the display control function 37b aligns and displays the captured scano image on the top board image 40 again (step S6).

  In this way, the radiographer or the like refers to the scanogram 80 displayed on the top image 40 until the subject is positioned at an appropriate position so that the part to be imaged is positioned at a position where vibration is small. During this period, scano images are repeatedly taken.

If it is determined by the radiologist or the like that the subject has been properly positioned (step S7, Yes), the imaging control function 37c is based on the position of the imaging area set on the scanogram by the operator. Thus, the photographing region for the main photographing is set (step S8).
Thereafter, the imaging control function 37c performs main imaging of the subject in response to a start instruction from the operator (step S9).
FIG. 12 is a flowchart showing a processing procedure of the main photographing performed by the photographing control function 37c according to the present embodiment.

  For example, as illustrated in FIG. 12, when the imaging control function 37c receives an instruction to start actual imaging from the operator (step S10, Yes), the imaging control function 37c first displays the top when the top plate 21 is moved to the imaging position. A decay time is derived until the magnitude of vibration generated at the position where the X-rays on the plate 21 cross each other becomes a predetermined value or less (step S11).

  Thereafter, the imaging control function 37c derives the moving speed of the top 21 that minimizes the sum of the moving time until the top 21 is moved to the imaging position and the derived decay time (step S12). Then, the imaging control function 37c controls the bed driving device 22 so as to move the top plate 21 to the imaging position at the derived movement speed (step S13).

  Subsequently, the imaging control function 37c captures the imaging area set using the scanogram when the derived decay time has elapsed after the top 21 has been moved to the imaging position (step S14, Yes). Is started (step S15). As a result, it is possible to automatically start imaging at the timing when the vibration generated at the position where the X-rays intersect on the top 21 is reduced to a predetermined value or less.

  For example, the photographing control function 37c does not automatically start photographing when the derived decay time has elapsed after the top 21 has been moved to the photographing position, but the decay time has elapsed. You may alert | report. For example, the imaging control function 37c displays a message on the display 32 to notify that the decay time has elapsed. In this case, the shooting control function 37c receives an operation for starting shooting from the operator, and starts shooting when triggered by the operation. As a result, it is possible to start imaging manually by the operator at the timing when the vibration generated at the position where the X-rays intersect on the top plate 21 is reduced to a predetermined value or less.

  The processing performed by the display control function 37b and the imaging control function 37c has been described above. Here, among the steps shown in FIG. 7, steps S1, S5, S8, and S9 are executed by, for example, the processing circuit 37 calling and executing a predetermined program corresponding to the shooting control function 37c from the storage circuit 35. Realized. Steps S2, S3, and S6 are realized, for example, when the processing circuit 37 calls and executes a predetermined program corresponding to the display control function 37b from the storage circuit 35. Each step shown in FIG. 12 is realized, for example, when the processing circuit 37 calls and executes a predetermined program corresponding to the photographing control function 37c from the storage circuit 35.

  In addition, although the example in the case of imaging | photography by moving the top plate 21 to one imaging | photography position was demonstrated here, embodiment is not restricted to this. For example, the imaging control function 37c moves the position of the top plate 21 at regular intervals and performs step-and-shoot type imaging in which conventional scanning is performed at a plurality of imaging positions. Each time it is moved, the decay time is derived as described above to control photographing.

  In addition, for example, the imaging control function 37 c performs a helical scan that rotates the rotating frame 15 while continuously moving the top 21 and scans the subject S in a spiral manner on the top 21. The moving speed of the top plate 21 and the rotating speed of the rotating frame 15 may be controlled in accordance with the magnitude of vibration generated at a position that intersects the X-ray path. In this case, for example, the imaging control function 37c moves the top plate 21 continuously, while the range where the vibration is large on the top plate 21 intersects the X-ray, compared with the range where the vibration is small. Thus, the moving speed of the top plate 21 and the rotating speed of the rotating frame 15 are controlled to be small. For example, as shown in FIG. 4, when the vibration generated on the top plate 21 is divided into three ranges of “small vibration”, “during vibration”, and “large vibration”, the imaging control function 37 c displays “vibration”. In the “medium” range, the moving speed of the top plate 21 and the rotation speed of the rotary frame 15 are controlled to be smaller than those in the “small vibration” range. As compared with the above, the moving speed of the top plate 21 and the rotating speed of the rotating frame 15 are controlled to be small.

  As described above, the X-ray CT apparatus 100 according to the present embodiment moves each position on the top 21 to a position where it intersects the X-ray path when the subject is positioned on the top 21. When this is done, information indicating the magnitude of vibration generated at each position is displayed. According to this configuration, when a radiographer or the like places the subject on the top plate 21, the subject is referred to so that the region to be imaged is placed at a position where vibration is small by referring to the displayed information. Can be positioned.

  Therefore, according to the present embodiment, it is possible to support appropriate positioning of the subject on the top board in consideration of vibration generated on the top board. In addition, as a result, it is possible to suppress deterioration in image quality due to vibration of the top plate.

  The term “processor” used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an application specific integrated circuit (ASIC), or a programmable logic device ( For example, it means circuits such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). The processor implements each function by reading and executing a program stored in the storage circuit 35. Instead of storing the program in the storage circuit, the program may be directly incorporated in the processor circuit. In this case, the processor realizes the function by reading and executing the program incorporated in the circuit. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, but may be configured as a single processor by combining a plurality of independent circuits to realize the function. Good.

  Each component of each device illustrated in the above embodiment is functionally conceptual and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or a part of each processing function performed in each device may be realized by a CPU and a program that is analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  According to at least one embodiment described above, it is possible to support appropriate positioning of the subject on the top board in consideration of vibration generated on the top board.

  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 100 X-ray CT apparatus 12 X-ray generator 12a X-ray tube 13 Detector 21 Top plate 37 Processing circuit 37a Movement control function 37b Display control function

Claims (17)

An X-ray tube that generates X-rays;
A detector for detecting the X-ray;
A top plate on which the subject is placed;
A movement control unit for controlling a movement mechanism for moving the top plate in the longitudinal direction;
A display control unit that displays information indicating the magnitude of vibration generated at each position when each position in the longitudinal direction on the top plate is moved to a position that intersects the X-ray path; Line CT device. The display control unit displays information indicating the magnitude of the vibration that occurs when imaging is performed based on the imaging condition according to the imaging condition.
The X-ray CT apparatus according to claim 1. The display control unit displays information indicating the magnitude of the vibration according to an imaging condition related to the orientation of the subject in the longitudinal direction when the subject is placed on the top board.
The X-ray CT apparatus according to claim 2. The display control unit displays information indicating the magnitude of the vibration that occurs when the subject with the weight is placed on the top board according to the weight of the subject.
The X-ray CT apparatus according to claim 2. The display control unit further displays information indicating a position serving as a reference for positioning the subject when the subject is placed on the top board.
The X-ray CT apparatus as described in any one of Claims 1-4. The display control unit displays information indicating the magnitude of vibration in association with a simulated image that schematically represents the shape of the subject or a positioning image of the subject.
The X-ray CT apparatus as described in any one of Claims 1-5. The display control unit displays information indicating the magnitude of vibration in association with a simulated image of the top board,
The X-ray CT apparatus according to claim 1. The display control unit displays a top plate image representing the shape of the top plate, and displays information indicating the magnitude of the vibration in association with each position on the top plate image.
The X-ray CT apparatus according to claim 1. The display control unit further aligns and displays a subject image representing the shape of the subject including a region to be imaged on the top image,
The X-ray CT apparatus according to claim 8. The display control unit displays the subject image by changing the size according to the height of the subject.
The X-ray CT apparatus according to claim 9. The display control unit can identify the part on the subject image when the part of the subject protrudes from the top plate when the subject image is aligned on the top image. indicate,
The X-ray CT apparatus according to claim 9 or 10. The display control unit simulates the shape of the subject so that a part to be imaged is arranged on the top plate at a position where the magnitude of the vibration is less than a predetermined value as the subject image. Display the simulated image
The X-ray CT apparatus according to claim 9, 10 or 11. The display control unit displays, as the subject image, a positioning image of the subject imaged for positioning of an imaging region imaged in actual imaging;
The X-ray CT apparatus according to claim 9, 10 or 11. When the top plate is moved to the imaging position, an attenuation time is derived until the magnitude of vibration generated at the position where the X-rays on the top plate intersect is equal to or less than a predetermined value, and based on the attenuation time A shooting control unit for controlling shooting;
The X-ray CT apparatus according to claim 1. The imaging control unit controls the moving speed of the top plate so that the total of the moving time until the top plate is moved to the imaging position and the decay time is minimized.
The X-ray CT apparatus according to claim 14. The imaging control unit starts the imaging when the decay time has elapsed after the top plate is moved to the imaging position.
The X-ray CT apparatus according to claim 14 or 15. The imaging control unit notifies that the decay time has elapsed when the decay time has elapsed after the top plate has been moved to the imaging position.
The X-ray CT apparatus according to claim 14 or 15.

Images