JP2009082205A - X-ray diagnostic apparatus and rotation angle deviation amount calculation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily match the reference positions of an X-ray detector and an X-ray restricting device. <P>SOLUTION: A restricting edge detection part 191 detects a restricting edge which is the edge of each of a plurality of restricting blades projected in an "X-ray image for deviation correction" from the luminance value of the "X-ray image for deviation correction" generated by an image data generation part 170, a relative rotation angle calculation part 192 calculates a relative rotation angle with respect to each "X-ray image periphery for deviation correction" of each restricting edge from position information in the "X-ray image for deviation correction" of each restricting edge detected by the restricting edge detection part 191, and a restricting edge angle calculation part 193 calculates a restricting edge angle as a rotation angle deviation amount between the X-ray restricting device 40 and the X-ray detector 70 on the basis of the relative rotation angle of each restricting edge calculated by the relative rotation angle calculation part 192. Then, a system control part 150 executes control so as to rotate the X-ray restricting device 40 on the basis of the restricting edge angle calculated by the restricting edge calculation part 193. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray diagnostic apparatus and a rotational angle deviation amount calculation program.

  Conventionally, an X-ray diagnostic apparatus detects X-rays transmitted through a patient (subject) and generates image data (X-ray images) based on the detected X-rays. Medical image diagnosis is possible. In an X-ray diagnostic apparatus, an X-ray diaphragm is attached between an X-ray tube that irradiates X-rays and the subject in order to protect the subject from unnecessary X-ray exposure. (See, for example, Non-Patent Document 1).

  For example, as shown in FIG. 11A, the X-ray diaphragm apparatus has four slidable diaphragm blades, and these diaphragm blades use X-rays emitted from the X-ray tube to diagnose the subject. According to the distance between the X-ray detector and the X-ray tube, the target region is automatically slid by the autocollimation function according to the distance between the X-ray detector and the X-ray tube. This avoids unnecessary X-ray exposure. In addition, FIG. 11 is a figure for demonstrating a prior art.

  Here, in recent X-ray diagnostic apparatuses, as an X-ray detector, a plane detection capable of generating an X-ray image with higher resolution instead of an image intensifier (II). A device equipped with a flat panel detector (FPD) has been developed (see, for example, Patent Document 1). In addition, I.I. I. The visual field detected by FPD has a round visual field, whereas the visual field detected by the FPD has a square visual field.

  In the X-ray diagnostic apparatus, when the C-arm that holds the X-ray detector and the X-ray diaphragm device rotates with respect to the floor axis, the X-ray receiving surface (angle) of the X-ray detector with respect to the subject shifts. Therefore, the generated X-ray image is rotated. Here, the X-ray detector is I.D. I. In this case, since the visual field to be detected is round, the generated X-ray image is rotated by software so that it is always upright on the screen (specifically, the head direction of the subject is always upward). X-ray images can be displayed. However, when the X-ray detector is an FPD, since the field of view to be detected is a square, if the generated X-ray image is rotated by software, a part of the diagnosis target area may not be displayed on the screen. .

  Therefore, in the X-ray diagnostic apparatus equipped with the FPD, the rotation mechanism and the position (angle) are respectively set to the X-ray detector and the X-ray diaphragm so that the generated X-ray image is always upright on the screen. ) Sensor, and in accordance with the rotational movement of the C arm with respect to the floor axis, the X-ray detector and the X-ray diaphragm device need to be controlled to follow up. For example, as shown in FIG. 11 (B), when the C-arm rotates clockwise with respect to the floor axis, the X-ray detector and the X-ray diaphragm device detect rotation angle information detected by the respective position sensors. The X-ray image can always be erected on the screen by rotating counterclockwise by each rotation mechanism so as to cancel the rotation of the C-arm based on the above.

  However, as shown in FIG. 12A, if a deviation occurs in the reference position between the X-ray detector (FPD) and the X-ray diaphragm device during the inspection, the generated X-rays even if the follow-up operation is performed. As shown in FIG. 12B, the image includes the diaphragm blades of the X-ray diaphragm device, and a part of the diagnosis target region is missing. That is, unnecessary exposure to X-rays occurs. In addition, FIG. 12 is a figure for demonstrating the subject of a prior art.

  For this reason, when assembling the product of the X-ray diagnostic apparatus, an operation for carefully adjusting the reference positions of the X-ray detector and the X-ray diaphragm apparatus is performed.

JIS standard Z4701 JP-A-9-75332

  By the way, the operation | work which matches the reference position of an X-ray detector and an X-ray aperture apparatus had the problem that much time and labor were required in a product assembly process. Specifically, the assembly operator took an X-ray image in the absence of the subject, and visually confirmed the taken X-ray image to confirm the deviation between the X-ray detector and the X-ray diaphragm device. In such a case, the mounting angles are adjusted so that the end faces of the X-ray detector and the X-ray diaphragm device are coincident (parallel). Further, these steps are repeated until the end faces of the X-ray detector and the X-ray diaphragm device are completely matched. After that, the assembly operator performs a process of adjusting the position sensor so that the rotation angle of the X-ray detector and the rotation angle of the X-ray diaphragm device coincide with each other. As described above, a great deal of time and labor are required to match the reference positions of the X-ray detector and the X-ray diaphragm apparatus. In addition, even at the time of product delivery, it is necessary for a service person to check whether or not the reference positions of the X-ray detector and the X-ray diaphragm device are matched on site.

  In addition, after product delivery, for example, if the position sensor malfunctions and the reference position between the X-ray detector and the X-ray diaphragm device is shifted, a service person visits the site, and after replacing the position sensor, The process described above must be performed, and much time and labor are required as in the product assembly process.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an X-ray diagnostic apparatus that can easily match the reference positions of the X-ray detector and the X-ray diaphragm device, and It is an object of the present invention to provide a rotation angle deviation calculation program.

  In order to solve the above-described problems and achieve the object, the present invention according to claim 1 is directed to a subject after the X-ray emitted from the X-ray tube is narrowed down by an X-ray diaphragm device having a plurality of diaphragm blades. An X-ray diagnostic apparatus that generates an X-ray image by detecting X-rays that have been irradiated and transmitted through the subject, and is reflected in the X-ray image from a luminance value of the X-ray image From the position information in the X-ray image of each of the diaphragm edges detected by the diaphragm edge detecting means, the diaphragm edge detecting means for detecting the diaphragm edge that is the edge of each of the plurality of diaphragm blades. Relative rotation angles of the respective aperture edges with respect to the respective X-ray image periphery are calculated, and rotations of the X-ray aperture device and the X-ray detection device are performed based on the calculated relative rotation angles of the respective aperture edges. Angle deviation amount and , A stop edge angle calculating means for calculating an edge angle aperture of Te characterized by comprising a.

  According to the seventh aspect of the present invention, the X-ray emitted from the X-ray tube is irradiated by the subject after being narrowed down by an X-ray diaphragm device having a plurality of diaphragm blades and transmitted through the subject. In an X-ray diagnostic apparatus that generates an X-ray image by detecting an X-ray detection apparatus, a rotation angle shift amount calculation method for calculating a rotation angle shift amount between the X-ray diaphragm apparatus and the X-ray detection apparatus is applied to a computer. A rotation angle deviation calculation program to be executed, wherein a diaphragm edge detection is performed to detect a diaphragm edge, which is the edge of each of the plurality of diaphragm blades reflected in the X-ray image, from the luminance value of the X-ray image. A relative rotation angle with respect to each X-ray image periphery of each of the diaphragm edges is calculated from the procedure and position information in the X-ray image of each of the diaphragm edges detected by the diaphragm edge detection procedure. A diaphragm edge angle calculation procedure for calculating a diaphragm edge angle as a rotation angle deviation amount between the X-ray diaphragm device and the X-ray detection device based on the relative rotation angle of each of the diaphragm edges, Is executed by a computer.

  According to the first or seventh aspect of the present invention, the reference positions of the X-ray detector and the X-ray diaphragm device can be easily matched.

  Exemplary embodiments of an X-ray diagnostic apparatus and a rotational angle deviation calculation program according to the present invention will be described below in detail with reference to the accompanying drawings.

  First, the configuration of the X-ray diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram for explaining the configuration of the X-ray diagnostic apparatus according to the first embodiment. As shown in FIG. 1, the X-ray diagnostic apparatus 100 according to the first embodiment includes an X-ray control unit 10, a high voltage generator 20, an X-ray tube 30, an X-ray diaphragm device 40, a top plate 50, C-arm 60, X-ray detector 70, C-arm rotation / movement mechanism 110, top-plate movement mechanism 120, C-arm / top-plate mechanism control unit 130, aperture control unit 140, system control unit 150, , An operation unit 160, an image data generation unit 170, a display unit 180, and a rotation angle deviation amount calculation unit 190.

  The X-ray control unit 10 controls the generation of a high voltage by the high voltage generator 20, thereby adjusting the X-ray dose emitted from the X-ray tube 30 to the subject P, and the subject from the X-ray tube 30. ON / OFF control of X-ray irradiation to P is performed.

  The high voltage generator 20 supplies a high voltage necessary for generating X-rays to the X-ray tube 30 according to the control of the X-ray controller 10, and the X-ray tube 30 is supplied from the high voltage generator 20. X-rays are emitted to the subject P using the voltage.

  The X-ray diaphragm device 40 has, for example, four slidable diaphragm blades, and these diaphragm blades receive X-rays radiated from the X-ray tube 30 under the control of a diaphragm controller 140 described later. It slides according to the distance of the X-ray detector 70 mentioned later and the X-ray tube 30 so that it may selectively irradiate with respect to this diagnostic object area | region.

  The top plate 50 placed on a bed (not shown) is a bed on which the subject P is placed, and the X-ray detector 70 detects X-rays that have passed through the subject P on the top plate 50.

  The X-ray detector 70 uses a TFT (thin film transistor) as a switching gate, and is a flat panel detector (FPD: Flat Panel Detector) that directly converts detected X-rays into digital data for each pixel. A square field of view.

  The C arm 60 is an arm that holds the X-ray tube 30, the X-ray diaphragm device 40, the X-ray detector 70, and the like.

  The C-arm rotation / movement mechanism 110 is a mechanism that rotates or moves the C-arm 60, and the top board movement mechanism 120 is a mechanism that rotates or moves the top board 50.

  The C arm / top plate mechanism control unit 130 is a control unit that controls the C arm rotation / movement mechanism 110 and the top plate movement mechanism 120 to rotate / move the C arm 60 and the top plate 50. The X-ray irradiation range is controlled by controlling the opening degree of the diaphragm blades of the X-ray diaphragm device 40.

  In addition, when the C arm 60 is rotated with respect to the floor axis by the C arm rotation / movement mechanism 110, the aperture control unit 140 controls the rotation of the X-ray aperture device 40 so as to cancel the rotation of the C arm 60. In addition, the C-arm / top plate mechanism control unit 130 controls the C-arm rotation / movement mechanism 110 to rotate the X-ray detector 70. Each of the X-ray diaphragm device 40 and the X-ray detector 70 includes a position sensor (angle sensor) (not shown). When the C-arm 60 rotates, the rotation angle detected by each position sensor. Based on the above, rotation control of the X-ray diaphragm device 40 and the X-ray detector 70 is performed.

  The system control unit 150 controls the entire X-ray diagnostic apparatus 100 by instructing the X-ray control unit 10, the C-arm / top plate mechanism control unit 130, the aperture control unit 140, and the like based on an instruction from the operation unit 160. . Further, the system control unit 150 controls the aperture control unit 140 and the C-arm / top plate mechanism control unit 130 </ b> C, so that the X-ray aperture device 40 and the X-ray detector 70 performed in conjunction with the rotation operation of the arm 60. Control the rotation of The operation unit 160 is a console that receives an instruction from the operator of the X-ray diagnostic apparatus 100 and transmits the instruction of the operator to the system control unit 150.

  The image data generation unit 170 generates an X-ray image from X-ray data transmitted through the subject P detected by the X-ray detector 70 that is an FPD. Specifically, the image data generation unit 170 converts X-rays detected by the X-ray detector 70 into electric signals, and further converts the converted electric signals into current and voltage. Then, the image data generation unit 170 converts the converted voltage signal into a digital signal, and generates an X-ray image by performing parallel / serial conversion on the converted digital signal.

  The display unit 180 includes a monitor, a speaker, and the like, and displays, for example, the X-ray image generated by the image data generation unit 170 on the monitor.

  As described above, the X-ray diagnostic apparatus 100 according to the first embodiment irradiates the subject P with the X-ray emitted from the X-ray tube 30 after being narrowed down by the X-ray diaphragm apparatus 40 having a plurality of diaphragm blades. The outline is that X-rays transmitted through the specimen P are detected by the X-ray detector 70, and the image data generation unit 170 generates an X-ray image based on the detected X-ray data. The X-ray diagnostic apparatus 100 according to the first embodiment easily matches the reference positions of the X-ray detector 70 that is an FPD and the X-ray diaphragm device 40 by the processing of the rotation angle deviation amount calculation unit 190 described below. The main feature is that it becomes possible.

  This main feature will be described with reference to FIGS. FIG. 2 is a block diagram illustrating a configuration of a rotation angle deviation amount calculation unit, FIG. 3 is a diagram for explaining a diaphragm edge detection unit, and FIG. 4 is a diagram for explaining a relative rotation angle calculation unit. FIG. 5 is a diagram for explaining the aperture edge angle calculation unit, and FIG. 6 is a diagram for explaining the aperture control unit.

  As shown in FIG. 2, the rotation angle deviation amount calculation unit 190 includes an aperture edge detection unit 191, a relative rotation angle calculation unit 192, and an aperture edge angle calculation unit 193, and further includes an image data generation unit. 170 and the system control unit 150.

  As an instruction from the operator of the X-ray diagnostic apparatus 100, when a generation request for “deviation correction X-ray image” is transmitted from the operation unit 160 to the system control unit 150, an image is generated based on the control of the system control unit 150. The data generation unit 170 generates a “deviation correction X-ray image” from the X-ray data detected by the X-ray detector 70. Here, the operator of the X-ray diagnostic apparatus 100 is an assembly operator, a service person, a clinical laboratory technician, or the like.

  The aperture edge detection unit 191 includes four images included in the X-ray aperture device 40 reflected in the “shift correction X-ray image” from the luminance value of the “shift correction X-ray image” generated by the image data generation unit 170. The aperture edge, which is the edge of each aperture blade, is detected. Here, since the four diaphragm blades included in the X-ray diaphragm device 40 are substances that do not transmit X-rays, a part of the diaphragm blades reflected in the “deviation correction X-ray image” is shown in FIG. As shown in A), the image is black.

  In other words, the diaphragm edge detection unit 191 detects the diaphragm edge that is the edge of each of the four diaphragm blades reflected from the change in the luminance value of the “deviation correction X-ray image” by image processing. For example, by processing the “deviation correction X-ray image” shown in FIG. 3A, four boundary lines whose luminance values change rapidly as shown in FIG. Detected as four diaphragm blades.

  Note that the “deviation correction X-ray image” is preferably an image taken in a state where the subject P is not on the top board 50 from the viewpoint of preventing unnecessary exposure of X-rays. The invention is not limited to this. For example, the X-ray image generated during the examination of the subject P is set as the “deviation correction X-ray image” so as to execute the aperture edge detection processing. It may be the case. In this case, the amount of X-ray unnecessary exposure that may occur during the inspection can be minimized.

  The relative rotation angle calculation unit 192 uses the positional information in the “deviation correction X-ray image” of each aperture edge detected by the aperture edge detection unit 191 to determine “peripheral deviation X-ray image periphery” of each aperture edge. The relative rotation angle for each is calculated. For example, as illustrated in FIG. 4, the relative rotation angle calculation unit 192 includes a portion of the periphery of the “deviation correction X-ray image” at the diaphragm edge detected at the lower right of the “deviation correction X-ray image”. The relative rotation angle (θ1) with respect to the line segment AB is calculated.

  For example, the relative rotation angle calculation unit 192 arbitrarily selects two points from the aperture edge detected at the lower right, and “a coordinate system having the point A as the origin, the vector AB as the X axis, and the vector AD as the Y axis. ”, (X1, Y1) and (X2, Y2) which are the coordinates of these two arbitrarily selected points are acquired. Then, the relative rotation angle calculation unit 192 uses the function arctan (arc tangent) to calculate the relative rotation angle (θ1) of the diaphragm edge detected in the lower right corner as “θ1 = arctan (Y2−Y1) / (X2). -X1) ".

  Also, the coordinates of two points arbitrarily selected from the aperture edge detected at the lower left shown in FIG. 4 are “coordinate system having point D as the origin, vector DA as the X axis, and vector DC as the Y axis”. The coordinates of two points that are acquired and arbitrarily selected from the aperture edge detected in the upper left shown in FIG. 4 are “a coordinate system with point C as the origin, vector CD as the X axis, and vector CB as the Y axis”. The coordinates of two points arbitrarily selected from the aperture edge detected at the upper right shown in FIG. 4 are “a coordinate system with point B as the origin, vector BC as the X axis, and vector BA as the Y axis. The relative rotation angles “θ2”, “θ3”, and “θ4” are calculated using these.

  In the present embodiment, the case where the relative rotation angle calculation unit 192 arbitrarily selects two points from the detected aperture edge and calculates the relative rotation angle has been described, but the present invention is not limited thereto. For example, the operator of the X-ray diagnostic apparatus 100 arbitrarily selects two points from the diaphragm edge on the “deviation correction X-ray image” displayed on the monitor of the display unit 180, and Based on this, the relative rotation angle calculation unit 192 may calculate the relative rotation angle. In addition to the two points selected from the diaphragm edge, the point can be arbitrarily changed by the setting of the operator of the X-ray diagnostic apparatus 100. For example, from the coordinates corresponding to three or more selected points, The inclination of the regression line may be calculated by the least square method, and the relative rotation angle may be calculated from the inclination.

  The aperture edge angle calculation unit 193 is used as a rotational angle deviation amount between the X-ray aperture device 40 and the X-ray detector 70 based on the relative rotation angle of each aperture edge calculated by the relative rotation angle calculation unit 192. The aperture edge angle is calculated. Here, the aperture edge angle calculation unit 193 calculates the aperture edge angle (θ) based on one of the following three methods according to an instruction from the operator of the X-ray diagnostic apparatus 100.

  As a first method, the diaphragm edge angle calculation unit 193 calculates the relative rotation angle of one arbitrarily selected diaphragm edge as it is as the diaphragm edge angle. For example, as shown in FIG. 5A, the relative rotation angle (θ1) shown in FIG. 4 is employed as it is as the aperture edge angle (θ). The selection method may be a case where the operator of the X-ray diagnostic apparatus 100 arbitrarily selects from the “deviation correction X-ray image” displayed on the monitor of the display unit 180, or in advance. The relative rotation angle at the lower right of the “deviation correction X-ray image” may be set to be adopted as the aperture edge angle. Here, in the latter case, the relative rotation angle calculation unit 192 may be set to calculate only the relative rotation angle of the diaphragm edge detected at the lower right of the “deviation correction X-ray image”. Thus, according to the first method, it is possible to shorten the processing time for calculating the aperture edge angle as the rotation angle deviation amount.

  As a second method, the aperture edge angle calculation unit 193 calculates an average value of the relative rotation angles of all the aperture edges as an aperture edge angle. That is, as shown in FIG. 5B, the average value of the relative rotation angles “θ1 to θ4” shown in FIG. 4 is calculated as the aperture edge angle (θ), and this value is calculated as the aperture edge angle (θ). θ) is adopted. Thus, according to the second method, it is possible to accurately calculate the aperture edge angle as the rotation angle deviation amount.

  As a third method, the aperture edge angle calculation unit 193 calculates the average value of the median values of the relative rotation angles of the aperture edges as the aperture edge angle. For example, as shown in (C) of FIG. 5, when the magnitude relationship of the relative rotation angles “θ1 to θ4” shown in FIG. 4 is as shown in (C) of FIG. Is calculated, and this value is adopted as the aperture edge angle (θ). As described above, according to the third method, if there is an “outlier” in the distribution of the relative rotation angle calculated by the relative rotation angle calculation unit 192, this can be excluded, and the rotation angle deviation amount It is possible to calculate the aperture edge angle as a more accurate.

  Note that, when the aperture blades in the vertical direction or the horizontal direction are further narrowed down than the narrowing by the auto-collimation function with respect to the “shift correction X-ray image”, the X-ray diaphragm device 40 and the X-ray detector 70 which is an FPD Even when there is no relative angular deviation with respect to the aperture blade, the aperture blade is displayed on the monitor. In such a case, the aperture edge angle is calculated only from the information on the aperture edge detected from the aperture blades that have been narrowed down. In the above case, since the aperture edge angle is “0 degree”, the rotation control for the X-ray aperture device 40 is not executed.

  The system control unit 150 controls the X-ray diaphragm device 40 to rotate based on the diaphragm edge angle calculated by the diaphragm edge angle calculator 193. That is, the aperture edge angle calculated by the aperture edge angle calculation unit 193 is determined as the rotational angle deviation amount between the X-ray aperture device 40 and the X-ray detector 70. For example, the system control unit 150 determines that the X-ray aperture device 40 is deviated by an angle “θ” counterclockwise with respect to the X-ray detector 70 as shown in FIG. Then, the system control unit 150 instructs the aperture control unit 140 to rotate the X-ray aperture device 40 clockwise by an angle “θ”. As a result, as shown in FIG. 6B, it is avoided that the diaphragm blades of the X-ray diaphragm device 40 are reflected in the X-ray image of the diagnosis target region.

  In the present embodiment, the case where the system control unit 150 controls the rotation of the X-ray diaphragm device 40 based on the diaphragm edge angle has been described, but the present invention is not limited to this, and the system control is performed. The unit 150 may control the rotation of the X-ray detector 70 based on the aperture edge angle. However, it is preferable to control the rotation of the X-ray diaphragm device 40 so that the X-ray image is always upright on the screen.

  Next, processing of the X-ray diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 7 is a diagram for explaining processing of the X-ray diagnostic apparatus according to the first embodiment.

  As shown in FIG. 7, the X-ray diagnostic apparatus 100 according to the first embodiment receives a deviation correction instruction from the operator of the X-ray diagnostic apparatus 100 (Yes in step S701), based on the control of the system control unit 150. The image data generation unit 170 generates a “deviation correction X-ray image” from the X-ray data detected by the X-ray detector 70 (step S702).

  The aperture edge detection unit 191 is included in the X-ray aperture device 40 that is reflected in the “deviation correction X-ray image” from the luminance value of the “deviation correction X-ray image” generated by the image data generation unit 170. A diaphragm edge that is the edge of each of the four diaphragm blades is detected (step S703). That is, the aperture edge detection unit 191 captured the brightness value of the “deviation correction X-ray image” shown in FIG. 3A by image processing as shown in FIG. A diaphragm edge, which is the edge of each of the four diaphragm blades, is detected.

  After that, the relative rotation angle calculation unit 192 uses the positional information in the “deviation correction X-ray image” of each aperture edge detected by the aperture edge detection unit 191 to detect “shift error X-rays” for each aperture edge. A relative rotation angle with respect to each of the “image periphery” is calculated (step S704). For example, as illustrated in FIG. 4, the relative rotation angle calculation unit 192 calculates the relative rotation angles (θ1 to θ4) for each of the four diaphragm edges detected in the “deviation correction X-ray image”. .

  Subsequently, the aperture edge angle calculation unit 193 determines the amount of rotational angle deviation between the X-ray aperture device 40 and the X-ray detector 70 based on the relative rotation angle of each aperture edge calculated by the relative rotation angle calculation unit 192. The aperture edge angle is calculated (step S705). At that time, the aperture edge angle calculation unit 193 calculates the aperture edge angle (θ) based on one of the three methods shown in FIGS.

  Then, the system control unit 150 controls the angle correction so as to rotate the X-ray diaphragm device 40 based on the diaphragm edge angle calculated by the diaphragm edge angle calculation unit 193 (step S706), and ends the process. To do. For example, as shown in FIG. 6A, the system control unit 150 determines that the X-ray diaphragm device 40 is offset by an angle “θ” counterclockwise with respect to the X-ray detector 70, and the diaphragm By instructing the control unit 140, the X-ray diaphragm device 40 is rotated clockwise by an angle “θ”. The series of processes described above are performed when the X-ray diagnostic apparatus 100 according to the first embodiment is assembled, before the inspection is started by the X-ray diagnostic apparatus 100 according to the first embodiment, and during the inspection by the X-ray diagnostic apparatus 100 according to the first embodiment. For example, it is executed at an arbitrary time according to an instruction from the operator of the X-ray diagnostic apparatus 100.

  As described above, in the first embodiment, on the basis of an instruction from the operator of the X-ray diagnostic apparatus 100, the image data generation unit 170 calculates “shift correction X” from the X-ray data detected by the X-ray detector 70. The aperture edge detection unit 191 generates X-rays reflected in the “deviation correction X-ray image” from the luminance value of the “deviation correction X-ray image” generated by the image data generation unit 170. A diaphragm edge that is an edge of each of the four diaphragm blades of the diaphragm device 40 is detected, and the relative rotation angle calculation unit 192 performs “shift correction” for each of the diaphragm edges detected by the diaphragm edge detection unit 191. From the position information in the “X-ray image”, a relative rotation angle with respect to each “periphery of the X-ray image for displacement correction” of each aperture edge is calculated, and the aperture edge angle calculation unit 193 is calculated by the relative rotation angle calculation unit 192. Squeezed edge Based on the relative rotation angle of respectively, to calculate the aperture edge angle as the rotational angle deviation between the X-ray diaphragm device 40 and the X-ray detector 70. Then, the system control unit 150 controls the angle correction so as to rotate the X-ray diaphragm device 40 based on the diaphragm edge angle calculated by the diaphragm edge angle calculation unit 193.

  For this reason, the rotational angle deviation between the X-ray diaphragm device 40 and the X-ray detector 70 can be automatically calculated, and the reference positions of the X-ray detector and the X-ray diaphragm device can be easily matched. It becomes possible. That is, it is possible to improve the work efficiency of an assembly worker, a service person, and the like. In addition, it is possible to avoid the inspection by the X-ray diagnostic apparatus 100 being interrupted for a long time by the repair work of the service person. Furthermore, it is possible to avoid unnecessary exposure of X-rays caused by a reference position shift between the X-ray diaphragm device 40 and the X-ray detector 70.

  In the first embodiment described above, the case where the X-ray diaphragm device 40 is rotated based on the calculated diaphragm edge angle has been described. However, in the second embodiment, the X-ray is based on the calculated diaphragm edge angle. A case where a warning is notified to the operator of the diagnostic apparatus 100 will be described.

  An X-ray diagnostic apparatus 100 according to the second embodiment will be described with reference to FIG. FIG. 8 is a diagram for explaining the configuration of the system control unit according to the second embodiment.

  As illustrated in FIG. 8, the system control unit 150 included in the X-ray diagnostic apparatus 100 according to the second embodiment newly includes a setting threshold storage unit 151 and a determination notification unit 152. The X-ray diagnostic apparatus 100 according to the second embodiment has the same configuration as that of the X-ray diagnostic apparatus 100 according to the first embodiment shown in FIGS.

  The setting threshold value storage unit 151 stores a setting threshold value set by the operator of the X-ray diagnostic apparatus 100. For example, “5 degrees” is stored as the setting threshold.

  The determination notification unit 152 determines the magnitude relationship between the aperture edge angle calculated by the aperture edge angle calculation unit 193 and the setting threshold value stored in the setting threshold value storage unit 151, and displays the result of the determined magnitude relationship. This is notified by the unit 180. That is, when the diaphragm edge angle calculated by the diaphragm edge angle calculation unit 193 is “10 degrees”, the determination notification unit 152 determines that the setting threshold is larger than “5 degrees”, and further displays the display unit. The monitor of 180 is controlled to display a warning “There is a possibility that unnecessary X-ray exposure may occur due to a reference position shift between the X-ray diaphragm device 40 and the X-ray detector 70”. In addition, when the diaphragm edge angle calculated by the diaphragm edge angle calculator 193 is “0.5 degrees”, the determination notification unit 152 determines that the setting threshold is smaller than “5 degrees”, and Control is performed so that “no abnormality” is displayed on the monitor of the display unit 180.

  Next, processing of the X-ray diagnostic apparatus according to the second embodiment will be described with reference to FIG. FIG. 9 is a diagram for explaining processing of the X-ray diagnostic apparatus according to the second embodiment.

  As shown in FIG. 9, the X-ray diagnostic apparatus 100 according to the second embodiment receives the deviation correction instruction from the operator of the X-ray diagnostic apparatus 100 (Yes at Step S901). As in steps S702 to S705 of the X-ray diagnostic apparatus 100 in “1”, “generation of X-ray image for deviation correction”, “detection of aperture edge”, “calculation of relative rotation angle”, and “calculation of aperture edge angle” Execute the process.

  Then, the determination notification unit 152 determines the magnitude relationship between the aperture edge angle calculated by the aperture edge angle calculation unit 193 and the setting threshold value stored in the setting threshold value storage unit 151, and the aperture edge angle calculation unit 193. Is equal to or larger than the set threshold value (Yes in step S906), the monitor of the display unit 180 displays “X due to the reference position deviation between the X-ray diaphragm device 40 and the X-ray detector device 70. Control is performed to display a warning “There is a possibility that unnecessary exposure to the line may occur” (step S907), and the process is terminated.

  On the other hand, the determination notification unit 152 determines the magnitude relationship between the aperture edge angle calculated by the aperture edge angle calculation unit 193 and the setting threshold value stored in the setting threshold value storage unit 151, and determines the aperture edge angle. When the aperture edge angle calculated by the calculation unit 193 is smaller than the set threshold (No at Step S906), the monitor of the display unit 180 is controlled to display “no abnormality” (Step S908), and the process is performed. finish.

  As described above, in the second embodiment, unnecessary exposure of X-rays is caused by the reference position shift between the X-ray diaphragm device 40 and the X-ray detector 70 by executing a series of processes before the inspection is performed, for example. The presence or absence of the possibility of occurrence can be recognized, and a highly safe X-ray diagnostic apparatus can be provided.

  In the first and second embodiments, the amount of rotational angle deviation between the X-ray diaphragm device 40 and the X-ray detector 70 is calculated using the diaphragm blades reflected in the “deviation correction X-ray image”. However, the present invention is not limited to this. For example, as shown in FIG. 10 which is a diagram for explaining a modification of the present invention, the position of the X-ray detector 70 is adjusted. In this case, the bed may be reflected in the “deviation correction X-ray image”, the bed edge may be detected from the reflected bed, and the rotational angle deviation amount may be calculated based on this. As a result, the X-ray image of the diagnosis target region can always be erect on the screen.

  Further, each component of each illustrated apparatus is functionally conceptual, and does not necessarily need to be physically configured as illustrated. That is, the specific form of dispersion / integration of each device is not limited to that shown in the figure, and for example, the relative rotation angle calculation unit 192 and the aperture edge angle calculation 193 shown in FIG. Can be configured to be functionally or physically distributed and integrated in arbitrary units according to various loads and usage conditions. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

  As described above, the X-ray diagnostic apparatus and the rotational angle deviation calculation program according to the present invention irradiate the subject with the X-rays narrowed by the X-ray diaphragm device, and detect the X-rays transmitted through the subject. This is useful when an X-ray image is generated by detection by an apparatus, and is particularly suitable for easily matching the reference positions of the X-ray detector and the X-ray diaphragm apparatus.

It is a figure for demonstrating the structure of the X-ray diagnostic apparatus in Example 1. FIG. It is a block diagram which shows the structure of a rotation angle deviation | shift amount calculation part. It is a figure for demonstrating a diaphragm edge detection part. It is a figure for demonstrating a relative rotation angle calculation part. It is a figure for demonstrating a diaphragm edge angle calculation part. It is a figure for demonstrating an aperture control part. It is a figure for demonstrating the process of the X-ray diagnostic apparatus in Example 1. FIG. FIG. 10 is a diagram for explaining a configuration of a system control unit according to a second embodiment. It is a figure for demonstrating the process of the X-ray diagnostic apparatus in Example 2. FIG. It is a figure for demonstrating the modification in this invention. It is a figure for demonstrating a prior art. It is a figure for demonstrating the subject of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 X-ray control part 20 High voltage generator 30 X-ray tube 40 X-ray aperture apparatus 50 Top plate 60 C arm 70 X-ray detector 100 X-ray diagnostic apparatus 110 C arm rotation and moving mechanism 120 Top plate moving mechanism 130 C arm Top plate mechanism control unit 140 Aperture control unit 150 System control unit 151 Setting threshold value storage unit 152 Judgment notification unit 160 Operation unit 170 Image data generation unit 180 Display unit 190 Rotation angle deviation amount calculation unit 191 Aperture edge detection unit 192 Relative rotation Angle calculation unit 193 Aperture edge angle calculation unit

Claims (7)

X-rays radiated from the X-ray tube are focused by an X-ray diaphragm device having a plurality of diaphragm blades, and then irradiated on the subject. X-rays transmitted through the subject are detected by the X-ray detector and X-rays are detected An X-ray diagnostic apparatus for generating an image,
A diaphragm edge detecting means for detecting a diaphragm edge that is a periphery of each of the plurality of diaphragm blades reflected in the X-ray image from the luminance value of the X-ray image;
From the positional information in the X-ray image of each of the diaphragm edges detected by the diaphragm edge detection means, a relative rotation angle with respect to each X-ray image periphery of each of the diaphragm edges is calculated, and the calculated diaphragm edge A diaphragm edge angle calculating means for calculating a diaphragm edge angle as a rotation angle deviation amount between the X-ray diaphragm device and the X-ray detector based on the relative rotation angle of each edge;
An X-ray diagnostic apparatus comprising:   The X-ray diagnostic apparatus according to claim 1, wherein the diaphragm edge angle calculating unit calculates the relative rotation angle of one arbitrarily selected diaphragm edge as the diaphragm edge angle.   The X-ray diagnostic apparatus according to claim 1, wherein the diaphragm edge angle calculating unit calculates an average value of relative rotation angles of all the diaphragm edges as the diaphragm edge angle.   The X-ray diagnostic apparatus according to claim 1, wherein the aperture edge angle calculation unit calculates an average value of median values of relative rotation angles of the aperture edges as the aperture edge angle.   The apparatus further comprises rotation control means for controlling the X-ray diaphragm apparatus or the X-ray detection apparatus to rotate based on the diaphragm edge angle calculated by the diaphragm edge angle calculating means. The X-ray diagnostic apparatus as described in any one of Claims 2-4. Setting threshold value storage means for storing a predetermined threshold value set in advance;
The magnitude relationship between the aperture edge angle calculated by the aperture edge angle calculating means and the predetermined threshold stored in the set threshold storage means is determined, and the result of the determined magnitude relationship is determined as a predetermined output unit. Determination notification means for informing at,
The X-ray diagnostic apparatus according to claim 2, further comprising: X-rays radiated from the X-ray tube are focused by an X-ray diaphragm device having a plurality of diaphragm blades, and then irradiated on the subject. X-rays transmitted through the subject are detected by the X-ray detector and X-rays are detected In the X-ray diagnostic apparatus for generating an image, a rotation angle deviation amount calculation program for causing a computer to execute a rotation angle deviation amount calculation method for calculating a rotation angle deviation amount between the X-ray diaphragm device and the X-ray detection device. ,
From the luminance value of the X-ray image, an aperture edge detection procedure for detecting an aperture edge that is an edge of each of the plurality of aperture blades reflected in the X-ray image;
A relative rotation angle with respect to each X-ray image periphery of each aperture edge is calculated from position information in the X-ray image of each aperture edge detected by the aperture edge detection procedure, and the calculated aperture edge A diaphragm edge angle calculation procedure for calculating a diaphragm edge angle as a rotation angle deviation amount between the X-ray diaphragm device and the X-ray detection device based on the relative rotation angle of each edge;
A computer program for causing a computer to execute a rotation angle deviation amount calculation program.

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