JP6132528B2 - X-ray diagnostic apparatus and image processing apparatus - Google Patents

Description

  Embodiments described herein relate generally to an X-ray diagnostic apparatus and an image processing apparatus.

  Conventionally, in imaging by an X-ray diagnostic apparatus, a method of continuously observing an observation object from another direction by rotating the C-arm and imaging the observation object is used. For example, this technique is used for observing the positional relationship between the tip of a wire and a contralateral blood vessel, a stent, or the like when treating a complete occlusion of a cardiac coronary artery.

  When the C-arm is rotated, the observation object positioned at the isocenter is projected on the center on the projection plane. On the other hand, an observation object positioned at a location away from the isocenter moves to the left and right on the projection plane, for example.

JP 2010-131371 A

  The problem to be solved by the present invention is to provide an X-ray diagnostic apparatus and an image processing apparatus that can improve the visibility of an observation target.

The X-ray diagnostic apparatus according to the embodiment includes an imaging unit, a correction unit, and a display control unit. The imaging unit rotates the support unit that supports the X-ray tube that irradiates X-rays and the X-ray detector that detects X-rays, and collects X-ray images on which the object is depicted. The correction unit calculates a movement amount of the object that moves in the X-ray image as the support unit rotates using a function that represents a correspondence relationship between the rotation angle of the support unit and the movement amount. The X-ray image is corrected using the calculated movement amount. The display control unit displays the corrected X-ray image on the display unit. Here, the function indicates that an amplitude representing a change in the movement amount corresponding to the change in the rotation angle is an isocenter and a predetermined point on a line connecting the X-ray tube and the center of the X-ray detector. It depends on the distance. The correction unit calculates a plurality of movement amounts using a plurality of functions having different amplitudes, and corrects the X-ray image using each of the calculated plurality of movement amounts. The display control unit displays a plurality of X-ray images corrected using the plurality of movement amounts on the display unit.

FIG. 1 is a diagram illustrating a configuration example of an X-ray diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram illustrating a gantry coordinate system according to the first embodiment. FIG. 3A is a diagram illustrating an example of a fluoroscopic image collected in the first embodiment. FIG. 3B is a diagram illustrating an example of a fluoroscopic image collected in the first embodiment. FIG. 3C is a diagram illustrating an example of a fluoroscopic image collected in the first embodiment. FIG. 4A is a diagram illustrating an example of movement of coordinates on the projection plane of the observation target when the C-arm is rotated by φ in the LAO direction. FIG. 4B is a diagram illustrating an example of the locus of coordinates on the projection plane to be observed when the C-arm is rotated by φ in the LAO direction or the RAO direction. FIG. 5 is a diagram illustrating an example of processing for selecting a projection function from the coordinates on the projection plane and the rotation angle. FIG. 6 is a diagram illustrating an example of a central region of an image extracted in the first embodiment. FIG. 7 is a diagram illustrating an example of a fluoroscopic image collected by the photographing unit and sent to the correction unit. FIG. 8 is a diagram illustrating an example of a fluoroscopic image displayed by the display control unit when the correction process is performed. FIG. 9 is a diagram illustrating another example of a fluoroscopic image collected by the photographing unit and sent to the correction unit. FIG. 10 is a diagram illustrating another example of the fluoroscopic image displayed by the display control unit. FIG. 11 is a flowchart illustrating a processing procedure performed by the X-ray diagnostic apparatus according to the first embodiment. FIG. 12 is a flowchart illustrating a procedure of correction processing by the correction unit. FIG. 13 is a diagram illustrating an example in which a perspective image is displayed by dividing the display area of the display unit. FIG. 14 is a diagram illustrating an example in which a fluoroscopic image is reduced and displayed on a display unit.

  Hereinafter, an X-ray diagnostic apparatus and an image processing apparatus according to embodiments will be described with reference to the drawings. The terms used below are defined. In the following embodiments, a “perspective image” is a moving image generated by detecting an X-ray that has passed through a subject with an X-ray detector, and is displayed in real time. On the other hand, the “photographed image” is a moving image generated by detecting an X-ray transmitted through the subject by an X-ray detector, as in the case of the fluoroscopic image. There are many images. The X-ray dose is determined, for example, according to the necessity of recording. For example, when it is necessary to record, “photographed images” with a large dose are collected. In the following embodiments, the “perspective image” and the “captured image” are moving images. However, when the term “X-ray image” is widely used, in addition to the “perspective image” and the “captured image” that are moving images, Still images are also included. The following embodiments will be described mainly using “transparent images” that are moving images, but the embodiments are not limited to this, and can be widely applied to “X-ray images” in the same manner. An image generally expressed in terms such as “transmission image” and “two-dimensional image” is also included in this “X-ray image”.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of an X-ray diagnostic apparatus 100 according to the first embodiment. As shown in FIG. 1, the X-ray diagnostic apparatus 100 includes a gantry unit 10 and a computer system 20. As shown in FIG. 1, the gantry unit 10 includes a bed 11, a gantry 12, a C arm 13, an X-ray tube 14, an X-ray detector 15, and a display unit 16. The X-ray diagnostic apparatus 100 does not include the subject P.

  The bed 11 is movable in the vertical direction and the horizontal direction, and the subject P is placed thereon. The gantry 12 supports the C arm 13. The C arm 13 supports the X-ray tube 14 and the X-ray detector 15 so as to face each other. The C arm 13 is also referred to as a support portion.

  The X-ray tube 14 emits X-rays. The X-ray detector 15 detects X-rays irradiated from the X-ray tube 14 and transmitted through the subject P. The pair of X-ray tube 14 and X-ray detector 15 is configured to rotate around a geometric center of rotation. This center of rotation is the isocenter.

  Here, a coordinate system (also referred to as a gantry coordinate system) in the gantry 10 will be described with reference to FIG. FIG. 2 is a diagram illustrating a gantry coordinate system according to the first embodiment. As shown in FIG. 2, the direction of the axis in the gantry 10 is perpendicular to the upper surface of the bed 11, the z-axis being the direction parallel to the long axis of the bed 11, the x-axis being the direction parallel to the short axis of the bed 11. The direction is set to the y-axis.

  The C arm 13 can rotate in the LAO (Left Anterior Oblique View) direction or the RAO (Right Anterior Oblique View) direction around the z axis. The rotation angle in the LAO direction or RAO direction is indicated by φ. The C-arm 13 can rotate in the CRA (Cranial view) direction or the CAU (Caudal view) direction around the x axis. The rotation angle in the CRA direction or CAU direction is indicated by θ.

  The display unit 16 is a monitor, for example, and displays an X-ray image such as a fluoroscopic image.

  Returning to FIG. 1, the computer system 20 includes an operation unit 21, a medical image data storage unit 22, a control unit 23, a C arm control unit 24, an imaging unit 25, a correction unit 26, and a display control unit 27. And a selection unit 28.

  The operation unit 21 is a control panel, a foot switch, a joystick, or the like, and receives input of various operations on the X-ray diagnostic apparatus 100 from an operator. Specifically, the operation unit 21 according to the first embodiment receives an X-ray image data collection instruction, a correction mode setting instruction, and the like.

  For example, the operation unit 21 receives an operation on the bed 11 for moving the observation target in the subject P to the center of the screen from the operator. Thereby, the control part 23 moves the bed 11 according to operation of an operator. The operation unit 21 receives an operation for rotating the C-arm 13 from the operator. Thereby, the C arm control part 25 rotates the C arm 13 according to an operator's operation. In addition, the operation unit 21 receives setting of shooting conditions from the operator. For example, the operation unit 21 receives an operation for setting a coronary artery as an observation target from the operator. Then, the operation unit 21 sends the observation target information set via the control unit 23 to the correction unit 26. For example, the operation unit 21 receives information such as SID (source-isocenter distance) and FOV (field of view) from the operator. Note that the X-ray diagnostic apparatus 100 may hold values such as SID and FOV in advance.

  In addition, the operation unit 21 receives an instruction to start the correction mode from the operator. The “correction mode” referred to here indicates that the function of the correction unit 26 is effective. For example, in the “correction mode”, the correction unit 26 cancels the movement of the observation target photographed in the fluoroscopic image from the center of the screen. Details of the correction unit 26 will be described later. The X-ray diagnostic apparatus 100 according to the first embodiment activates the correction mode when instructed by the operator.

  The medical image data storage unit 22 stores X-ray image data and the like. The control unit 23 performs overall control of the X-ray diagnostic apparatus 100. The C arm control unit 24 controls the rotation of the C arm 13 and the like under the control of the photographing unit 25.

  The imaging unit 25 rotates the C-arm 13 that supports the X-ray tube 14 that irradiates the subject P with X-rays and the X-ray detector 15 that detects the X-rays transmitted through the subject P around the isocenter. Thus, an X-ray image of the subject P is taken.

  For example, when receiving an instruction for collecting fluoroscopic image data from the operator via the operation unit 21, the imaging unit 25 controls the X-ray tube 14, the X-ray detector 15, and the C-arm control unit 24 to control the fluoroscopic image data. To collect. Here, the imaging unit 25 collects images in which the X-rays irradiated on the subject P are projected by the X-ray detector 15. The imaging unit 25 sends the collected fluoroscopic image data to the correction unit 26 and the display control unit 27. Note that the operator usually performs an operation of moving the observation target to the center of the screen at the preparation stage for starting imaging for diagnosis. At this time, the observation target should be positioned on a line connecting the X-ray tube 14 and the center point of the X-ray detector 15. However, the X-ray diagnostic apparatus 100 according to the first embodiment cannot specify where the observation target is positioned on the line connecting the X-ray tube 14 and the center point of the X-ray detector 15. The angle of the C arm 13 at this time in the LAO direction or the RAO direction is referred to as a “first angle”.

  Next, an example of a fluoroscopic image photographed by the photographing unit 25 will be described with reference to FIGS. 3A to 3C. 3A to 3C are diagrams illustrating examples of fluoroscopic images collected in the first embodiment. 3A to 3C show a case where the observation target is a wire and the C arm 13 is rotated in the RAO direction or the LAO direction. Note that the wire 30 to be observed is positioned above the isocenter on the line connecting the X-ray tube 14, the isocenter, and the X-ray detector 15 at the first angle. In normal fluoroscopic imaging, for example, a guide wire is used for a blood vessel. Here, for convenience of explanation, a diagram in which the wire 30 is regarded as a guide wire is used.

  As shown in FIG. 3A, the wire 30 to be observed is positioned on the right side of the center of the screen. When the C-arm 13 is rotated in the RAO direction from FIG. 3A, the wire 30 as the observation object moves to the right side of the screen as shown in FIG. 3B. On the other hand, when the C-arm 13 is rotated in the LAO direction from FIG. 3A, as shown in FIG. 3C, the wire 30 to be observed moves to the left side of the screen.

  The locus of coordinates on the projection plane to be observed will be described with reference to FIGS. 4A and 4B. FIG. 4A is a diagram illustrating an example of movement of coordinates on the projection plane of the observation target when the C-arm 13 is rotated by φ in the LAO direction. FIG. 4B is a diagram illustrating an example of the locus of coordinates on the projection plane to be observed when the C-arm 13 is rotated by φ in the LAO direction or the RAO direction.

  First, the coordinate system on the projection plane will be described with reference to FIG. 4A. As shown in FIG. 4A, the coordinate system on the projection plane is defined by the C axis and the R axis, and the coordinates on the projection plane are defined by (c, r). FIG. 4A shows an example of movement of coordinates on the projection plane of the isocenter 40, the observation object 41, and the observation object 42. As shown in FIG. 4A, the isocenter 40, the observation object 41, and the observation object 42 are projected onto the center coordinates on the projection plane at the first angle. Here, when the number of pixels in the display area of the display unit 16 is 1024 × 1024, the coordinates on the projection plane of the isocenter 40, the observation target 41, and the observation target 42 are (512, 512). Note that 0 <= c <1024 and 0 <= r <1024.

  Even when the C-arm 13 is rotated by φ in the LAO direction, the isocenter 40 is projected onto the center coordinates on the projection plane as shown in FIG. 4A. As shown in FIG. 4A, when the C-arm 13 is rotated φ in the LAO direction, the observation object 41 positioned above the isocenter is projected on the left side of the center coordinate on the projection plane. The C coordinate on the projection plane of the observation target 41 indicates a locus 43 in FIG. 4B. Note that the R coordinate does not move on the projection plane. That is, it is the same as the R coordinate of the center coordinate on the projection plane.

  On the other hand, as shown in FIG. 4A, when the C-arm 13 is rotated by φ in the LAO direction, the observation object 42 positioned below the isocenter is projected to the right of the center coordinates on the projection plane. The C coordinate on the projection plane of the observation object B indicates a locus 44 in FIG. 4B. Note that the R coordinate does not move on the projection plane. That is, it is the same as the R coordinate of the center coordinate on the projection plane. A function indicating the trajectory 43 and the trajectory 44 is referred to as a “projection function”. This projection function is a function representing the correspondence between the rotation angle of the C arm 13 and the amount of movement. The rotation angle that changes every moment from the first angle is referred to as a “second angle”.

  Here, the projection function will be described. The C coordinate when the point (x, y, z) in the gantry coordinate system is projected is calculated by the following projection function, “c = (Δc / w) · S · (xcosφ−ysinφ)”. However, “w = xsinφ · cosθ + cosφ · cosθ−zsinθ + L”. Here, L is the distance between the X-ray tube 14 and the isocenter, S is the distance between the X-ray tube 14 and the X-ray detector 15, Δc is the spatial resolution of the X-ray detector 15, and φ is LAO. The angle θ represents the CRA angle. That is, the C coordinate on the projection plane at the second angle of the observation target at (x, y, z) is (x, y, z) because L, S, θ, and Δc are fixed values. It is determined by a function with φ. In other words, the C coordinate on the projection plane at the second angle of the observation target positioned at the point (x, y, z) in the gantry coordinate system is expressed by a function having a different amplitude depending on the distance from the isocenter. . When the image size is 1024 (pixels) × 1024 (pixels), the coordinates when the isocenter is projected at the first angle and the second angle are (512, 512). The coordinates when the observation target is projected at the first angle are (512, 512). The coordinates when the observation target is projected at the second angle are (c, 512).

  In this way, in the fluoroscopic imaging using the X-ray diagnostic apparatus 100 that images the subject P by rotating the C-arm 13, the central points of the X-ray tube 14 and the X-ray detector 15 at the first angle are used. The observation object positioned above or below the isocenter on the line connecting the lines moves to the left and right on the projection screen. For this reason, it may be difficult for the operator to visually recognize the observation target. Therefore, the computer system 20 according to the first embodiment executes correction processing using the correction unit 26 shown in FIG.

  The correction unit 26 calculates the amount of movement of the observation target that moves in the X-ray image with the rotation of the C arm 13 using a projection function that represents the correspondence between the rotation angle of the C arm 13 and the amount of movement. The X-ray image is corrected using the calculated movement amount.

  In addition, when the radiographing image is selected by the selection unit 28 (to be described later) when continuously performing imaging with the same subject P, the correcting unit 26 selects a projection function used for correcting the selected fluoroscopic image. Then, the correction unit 26 corrects the fluoroscopic image sent from the imaging unit 25 using the selected projection function, and outputs the corrected fluoroscopic image to the display control unit 27.

  The display control unit 27 displays the fluoroscopic image corrected by the correction unit 26 on the display unit 16. For example, the display control unit 27 displays the fluoroscopic image corrected by the correction unit 26 in a strip form on the display unit 16.

  Further, the display control unit 27 selects a fluoroscopic image selected from the selection unit 28 described later and displays the selected fluoroscopic image on the display unit 16. For example, when the fluoroscopic image captured by the imaging unit 25 is repeatedly displayed, the display control unit 27 displays the fluoroscopic image selected by the selection unit 28 on the full screen.

  The selection unit 28 selects, from a plurality of fluoroscopic images, a fluoroscopic image having a minimum movement amount of the observation target from the fluoroscopic images displayed on the display unit 16 by the display control unit 27. For example, the selection unit 28 receives the selection of the fluoroscopic image from the operator. At this time, the operator is highly likely to select a fluoroscopic image in which the amount of movement of the observation target is the minimum, that is, a fluoroscopic image in which the observation target remains near the center of the fluoroscopic image.

  Next, the correction process by the correction unit 26 according to the first embodiment will be described in detail. In the first embodiment, the correction unit 26 projects the amount of movement of the observation object that moves in the X-ray image with the rotation of the C arm 13 and represents the correspondence between the rotation angle of the C arm 13 and the amount of movement. A “first stage” calculated using the function and a “second stage” for correcting the X-ray image using the calculated movement amount are executed.

  The correction unit 26 executes the following processing as the “first stage”. For example, the correction unit 26 sets coordinates positioned at the maximum movement amount on the projection plane from the following imaging conditions received from the operator. For example, the operator takes an image by rotating the C arm 13 while tracking the observation target displayed on the screen of the display unit 16. For this reason, it is considered that the observation target is displayed at least in the screen of the display unit 16 at the time of photographing. That is, it is considered that the observation target is located at the center of the screen at the first angle and moves to the edge of the screen at the maximum at the second angle. Further, for example, since the operator recognizes the positional relationship of the observation object in three dimensions, when the coronary artery is set as the observation object, the rotation angle of the C arm 13 is considered to be about 30 degrees at the maximum. For this reason, for example, when the coronary artery is set as the observation target, the correction unit 26 sets the position projected at the end on the projection plane at 30 degrees as the coordinate positioned at the maximum movement amount on the projection plane. .

  Here, when the correction unit 26 sets the position projected on the end portion (c = 1024) on the projection plane rotated by 30 degrees to the coordinates positioned at the maximum movement amount on the projection plane, the heart beats. Therefore, the observation target may be out of the coordinates on the projection plane. For this reason, it is desirable that the correction unit 26 does not set the C coordinate on the projection plane to 1024. Therefore, the correction unit 26 sets, for example, (512 * (N−1) / N * Δc, 512) as the C coordinate positioned at the maximum movement amount on the projection plane. Here, a case where N is 5 and c is 921 will be described.

  Further, in the “first stage”, the correction unit 26 determines the number of display area divisions (N) from the image size. For example, when dividing the display area, the correction unit 26 assigns to each display area the number of pixels within the range in which the observation target is contained in the divided display area. For example, when the image size is 1024 (pixels) × 1024 (pixels), the correction unit 26 sets the display area division number (N) to 5. The division number (N) of the display area can be changed. For example, when the image size is 1024 (pixels) × 1024 (pixels), the correction unit 26 may set the division number (N) of the display area to 3.

  For example, the processing of the correction unit 26 when the coronary artery is set as an observation target will be described. When the coronary artery is set as an observation target, the correction unit 26 predicts that the rotation angle is within a range of 30 degrees. The observation object is not limited to the cardiac coronary artery. Further, the correction unit 26 stores information in which the maximum rotation angle and the like are associated with each other according to the shooting conditions.

  Then, the correction unit 26 selects a projection function from the coordinates on the projection plane and the rotation angle. A process of selecting a projection function from the coordinates on the projection plane and the rotation angle will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of processing for selecting a projection function from the coordinates on the projection plane and the rotation angle. FIG. 5 shows the projection functions 51 to 55. In the example illustrated in FIG. 5, the correction unit 26 selects the projection function 55 in which c is 921 and φ is 30.

  In this manner, the correction unit 26 selects the function f1 indicating the locus of coordinates positioned at the maximum movement amount on the projection plane obtained by rotating the C arm 13 by 30 degrees. Next, the correction unit 26 selects a function indicating a locus of other coordinates on the projection plane obtained by rotating the C arm 13 by 30 degrees.

  For example, when the division number (N) of the display area is set to 5, the correction unit 26 selects the projection function f2 for the coordinates (460.5, 512) on the projection plane, and projects the coordinates (512, 512). The function f3 is selected, the projection function f4 is selected for (−460.5, 512), and the projection function f5 is selected for (−921, 512).

  Then, the correction unit 26 executes the following processing as the “second stage”. When the correction mode is set, the correction unit 26 acquires image data from the photographing unit 25 and also acquires a rotation angle from the C arm control unit 24 as needed. Then, the correction unit 26 calculates the C coordinate on the projection plane from the selected projection function and rotation angle, and shifts the acquired image data in a direction in which the movement of the calculated C coordinate is cancelled.

  For example, the correction unit 26 refers to the calculation result of the coordinates (c, 512) on the projection plane for each rotation angle using the projection function f1, and the coordinates (c, 512) are the projection plane for the collected images. The image is corrected so as to move to the coordinates (512, 512) of the above isocenter. In other words, the correction unit 26 moves the entire image in the C coordinate direction by “c−512” to generate a corrected image. Thereby, on the newly generated corrected image, the observation target is positioned at the isocenter, so that it does not seem to move.

  The above operation shows the case where the correction unit 26 uses the projection function f1. Similarly, the correction unit 26 calculates the coordinates of the projection plane using the projection functions f2 to f5, and executes correction processing. Thereby, the correction unit 26 generates corrected images for the number of divisions (N) of the display area. The correction unit 26 outputs the generated corrected image to the display control unit 27.

  The correction unit 26 may execute the “first stage” process when the shooting condition is set, and may execute the “second stage” process after the shooting is started.

  Next, display processing by the display control unit 27 according to the first embodiment will be described in detail. The display control unit 27 extracts the central region of each generated correction image, displays the central region of each extracted correction image in a strip shape, and displays it on the display unit 16. The central area of the image extracted by the display control unit 27 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of a central region of an image extracted in the first embodiment.

  As shown in FIG. 6, the display control unit 27 extracts a central region 50 excluding both end portions from each corrected image. The size (number of pixels) of the central area is determined by the number of divisions (N) of the display area determined by the correction unit 26.

An example of the fluoroscopic image displayed by the display control unit 27 will be described with reference to FIGS.
FIG. 7 is a diagram illustrating an example of a fluoroscopic image collected by the photographing unit 25 and sent to the correction unit 26. FIG. 8 is an example of a fluoroscopic image displayed by the display control unit 27 when correction processing is performed. FIG.

  FIG. 7 shows a case where the observation target is the wire 30 and the C-arm 13 is rotated in the RAO direction. Note that the wire 30 to be observed is positioned below the isocenter on the line connecting the X-ray tube 14, the isocenter, and the X-ray detector 15 at the first angle. As shown in FIG. 7, the wire 30 to be observed is located on the right side of the screen, and moves to the left side of the screen as the C arm 13 rotates.

  As shown in FIG. 8, the display control unit 27 extracts the central area of each perspective image corrected using the five projection functions, and arranges the extracted central areas of the corrected images in a strip shape on the display unit 16. indicate. In the example of FIG. 7, in the perspective image displayed at the right end of the display area, the tip of the wire 30 is displayed without substantially moving even when the C arm 13 is rotated.

  FIG. 9 is a diagram illustrating another example of the fluoroscopic image collected by the photographing unit 25 and sent to the correction unit 26, and FIG. 10 is a diagram illustrating another example of the fluoroscopic image displayed by the display control unit 27. .

  FIG. 9 shows a case where the observation target is a wire and the C-arm 13 is rotated in the RAO direction. Note that the wire 30 to be observed is positioned below the isocenter on the line connecting the X-ray tube 14, the isocenter, and the X-ray detector 15 at the first angle. As shown in FIG. 8, the wire 30 to be observed is located on the right side of the screen, and moves to the left side of the screen as the C arm 13 rotates.

  As shown in FIG. 10, the display control unit 27 extracts the central region of each fluoroscopic image corrected using five projection functions, and arranges the central regions of the extracted correction images in a strip shape on the display unit 16. indicate. In the example of FIG. 10, in the perspective image displayed at the right end of the display area, the tip of the wire 30 is displayed without substantially moving even when the C arm 13 is rotated.

(Processing procedure)
Next, a processing procedure performed by the X-ray diagnostic apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 11 is a flowchart showing a processing procedure performed by the X-ray diagnostic apparatus 100 according to the first embodiment.

  As shown in FIG. 11, the X-ray diagnostic apparatus 100 according to the first embodiment receives an input of imaging conditions from an operator (step S101). For example, the X-ray diagnostic apparatus 100 according to the first embodiment accepts an operation for selecting a cardiac coronary artery as an observation target from an operator. Thereby, the X-ray diagnostic apparatus 100 according to the first embodiment predicts that the rotation angle φ of the cardiac coronary artery is 30 degrees in the RAO direction and the LAO direction.

  Subsequently, the X-ray diagnostic apparatus 100 according to the first embodiment receives an operation for moving the bed 11 and the C arm 13 from the operator so that the observation target can be positioned at the center of the display unit 16 (step S102). . Then, the X-ray diagnostic apparatus 100 according to the first embodiment accepts activation of the correction mode from the operator (step S103).

  The X-ray diagnostic apparatus 100 according to the first embodiment receives an operation of rotating the C arm 13 from the operator, and rotates the C arm 13 to capture a fluoroscopic image of the subject P (step S104). Subsequently, the X-ray diagnostic apparatus 100 according to the first embodiment executes a correction process (step S105). Details of the correction process will be described later. Then, the X-ray diagnostic apparatus 100 according to the first embodiment displays the corrected fluoroscopic image on the display unit 16 (step S106).

  The X-ray diagnostic apparatus 100 according to the first embodiment determines whether the selection of the fluoroscopic image displayed on the display unit 16 has been accepted (step S107). Here, when the X-ray diagnostic apparatus 100 according to the first embodiment determines that the selection of the fluoroscopic image displayed on the display unit 16 has been accepted (Yes in step S107), the selected fluoroscopic image is displayed on the display unit 16. It is displayed (step S108). For example, the X-ray diagnostic apparatus 100 according to the first embodiment displays a fluoroscopic image selected from the fluoroscopic images from which the central region is extracted. Alternatively, the X-ray diagnostic apparatus 100 according to the first embodiment supplements and displays an area other than the central area extracted for the selected fluoroscopic image.

(Correction process)
Next, the procedure of the correction process by the correction unit 26 will be described with reference to FIG. FIG. 12 is a flowchart showing a procedure of correction processing by the correction unit 26.

  As shown in FIG. 12, the correction unit 26 determines the number of divisions (N) of the display area from the image size (step S201). For example, when the image size is 1024 pixels, the correction unit 26 sets the number of divisions (N) of the display area to 5.

  Then, the correction unit 26 sets coordinates on the projection plane based on the shooting conditions (step S202). For example, the correction unit 26 sets the coordinates positioned at the maximum movement amount on the projection plane based on the shooting conditions. Here, when the coordinate positioned at the maximum movement amount on the projection plane is 921 and the division number (N) of the display area is 5, the correction unit 26 performs (921, 512), (460.5, 512). ), (512, 512), (−460.5, 512), and (−921, 512) are set as coordinates on the projection plane.

  Subsequently, the correction unit 26 selects a projection function used for the correction process (step S203). For example, the correction unit 26 selects a projection function for each coordinate based on the coordinates on the projection plane. For example, the correction unit 26 selects the projection function f1 for the coordinates (921, 512) on the projection plane, selects the projection function f2 for the coordinates (460.5, 512), and coordinates (512, 512). The projection function f3 is selected for, the projection function f4 is selected for (−460.5, 512), and the projection function f5 is selected for (−921, 512).

  The correction unit 26 acquires X-ray image data from the imaging unit 25 and acquires a rotation angle from the C-arm control unit 24 (step S204). Then, the correction unit 26 corrects the acquired X-ray image data so that the C coordinate on the projection plane calculated using the projection function is moved to the coordinates (512, 512) of the isocenter ( Step S205). For example, the correction unit 26 corrects the image so that the coordinates (c, 512) are moved to the coordinates (512, 512) of the isocenter on the projection plane with respect to the collected X-ray image data.

(Modification)
In the above-described embodiment, the correction unit 28 calculates a plurality of movement amounts of the object and corrects the fluoroscopic image using the calculated plurality of movement amounts. However, the present invention is not limited to this. . For example, when the rotation angle of the C-arm 13 is small and the movement amount on the projection surface is small, the correction unit 28 may correct the fluoroscopic image by calculating one movement amount of the object.

  The display control unit 27 may display the fluoroscopic images corrected for each coordinate on the projection plane on the display unit 16 in a predetermined order. In addition, the display control unit 27 may divide the display area of the display unit 16 and display each perspective image in the divided display area. For example, as shown in FIG. 13, the display control unit 27 divides the display area of the display unit 16 into four and displays a corrected perspective image in each divided area. FIG. 13 is a diagram illustrating an example of displaying a perspective image by dividing the display area of the display unit 16.

  Further, the display control unit 27 may reduce and display each perspective image corrected for each coordinate on the projection plane on the display unit 16. For example, in the example shown in FIG. 10, the display control unit 27 extracts and displays a region corresponding to 1 / N from each fluoroscopic image, but as shown in FIG. 14, the size of the fluoroscopic image itself is displayed. Each perspective image reduced to 1 / N may be displayed on the display unit 16. FIG. 14 is a diagram illustrating an example in which a fluoroscopic image is reduced and displayed on the display unit 16.

  In general, the X-ray diagnostic apparatus may display the collected image again in real time and then display the image displayed in real time again. For example, the X-ray diagnostic apparatus repeatedly displays an image displayed in real time a few times in response to a request from the operator after the X-ray irradiation is completed. In the first embodiment described above, the display control unit 27 displays the corrected N images side by side when displaying the collected images in real time. Further, the selection unit 28 selects one image in which the observation target appears to stop from the N images displayed in real time. Thereby, the display control unit 27 displays only one image in which the observation target selected by the selection unit 28 appears to stop when repeatedly displaying the image displayed in real time in response to a request from the operator. Is possible. In this case, since the display control unit 27 does not have to display N images side by side, it is also possible to enlarge and display an image in which the observation target is stopped. Here, in the above-described first embodiment, an example has been described in which the selection unit 28 receives a selection from the operator as an image in which the observation target appears to stop, with the fluoroscopic image having a small amount of movement of the observation target being described. May automatically select an image in which the observation object appears to stop without receiving an image selection from the operator. For example, the selection unit 28 may recognize each of the five fluoroscopic images and select the fluoroscopic image that the observation target does not move most. Specifically, the selection unit 28 recognizes the observation target as an object for each frame of the fluoroscopic image, and selects the fluoroscopic image in which the observation target is the least moving based on the amount of movement of the object between successive frames. . For example, the selection unit 28 selects a fluoroscopic image having the smallest average moving amount of objects between consecutive frames as a fluoroscopic image in which the observation target does not move most.

  When the selection unit 28 selects a fluoroscopic image with a small movement amount of the observation target, the selection unit 28 detects the gaze direction of the operator, and the fluoroscopic image with the minimum movement amount is positioned ahead of the detected gaze direction. You may choose. For example, the selection unit 28 can be realized by a known technique. For example, the selection unit 28 includes a camera and performs pattern matching on an image captured by the camera. For example, as a pattern used for pattern matching, images of “human eyes” that differ depending on the line-of-sight direction are used. And the selection part 28 detects an operator's gaze direction.

  In the first embodiment described above, the correction unit 26 performs the correction process by receiving an instruction to activate the correction mode from the operator via the operation unit 21. Even if an instruction to activate the correction mode is not received from the operator, the correction process may be executed when the image is taken while the C-arm 13 is rotated.

  Further, although the correction unit 26 generates the corrected image using the projection function, as a result, the corrected image and the projection function are uniquely associated. For this reason, selecting a corrected image in which the observation target is least moved is equivalent to selecting a projection function in which the observation target is least moved. Therefore, when the X-ray image is captured for the second time and thereafter, the correction unit 26 may perform the correction process using only the projection function selected as the projection function in which the observation target does not move most. As a result, the correction unit 26 needs to generate only one corrected image. As a result, the display control unit 27 can display a large image on the screen in real time without dividing the display area into N parts.

  Moreover, although the X-ray diagnostic apparatus 100 demonstrated the example which correct | amends the fluoroscopic image which the own apparatus image | photographed, embodiment is not limited to this. For example, an image processing apparatus different from the X-ray diagnostic apparatus 100 may perform correction. In this case, the image processing apparatus receives a fluoroscopic image from the X-ray diagnostic apparatus 100 and performs a correction process on the fluoroscopic image. Further, the image processing apparatus may display the corrected fluoroscopic image on the display unit of the own apparatus or may transfer it to the X-ray diagnostic apparatus 100. Thereby, the X-ray diagnostic apparatus 100 can display the corrected fluoroscopic image on the display unit 16. That is, the image processing apparatus stores the fluoroscopic image acquired from the X-ray diagnostic apparatus 100. Then, the image processing apparatus calculates the movement amount of the observation target that moves in the X-ray image with the rotation of the C arm 13 using a function that represents the correspondence between the rotation angle of the C arm 13 and the movement amount. The fluoroscopic image is corrected using the calculated movement amount.

  As described above, according to the first embodiment, the observation target appears to be stopped near the center in any of the fluoroscopic images. Thereby, for example, the doctor can observe an image in which the movement of the observation target is suppressed in any of the fluoroscopic images. That is, according to the first embodiment, the visibility of the observation target can be improved.

  Further, according to the first embodiment, the amount of movement of the object is calculated by the number determined based on the size of the display area. Accordingly, an appropriate number of image candidates in which the movement of the observation target is suppressed is displayed, and the possibility that a fluoroscopic image with a small amount of movement of the observation target is selected can be increased.

  In addition, the display control unit 27 extracts the center region of the corrected fluoroscopic image and displays it in a strip shape. A fluoroscopic image with a small amount of movement of the observation target is displayed in the central area of the image. That is, according to the first embodiment, the operator can easily select a fluoroscopic image with a small amount of movement of the observation target from among the corrected fluoroscopic images.

  In addition, the selection unit 28 detects the line-of-sight direction and selects a fluoroscopic image. Accordingly, the operator can omit the process of selecting a fluoroscopic image with a small amount of movement of the observation target, and thus can select a fluoroscopic image with a small amount of movement of the observation target even during surgery.

  In addition, after the selection unit 28 selects a fluoroscopic image with a small amount of movement of the observation target, the correction unit 26 generates a fluoroscopic image with a small amount of movement of the observation target. Then, the display control unit 27 displays a fluoroscopic image with a small amount of movement of the observation target. Thereby, the operator can observe the fluoroscopic image which improved the visibility of the observation object.

  According to the X-ray diagnostic apparatus and image processing apparatus of at least one embodiment described above, the visibility of an observation target can be improved.

  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.

25 Imaging unit 26 Correction unit 27 Display control unit 100 X-ray diagnostic apparatus

Claims (7)

An imaging unit that collects an X-ray image in which an object is depicted by rotating a support unit that supports an X-ray tube that emits X-rays and an X-ray detector that detects X-rays;
The amount of movement of the object that moves in the X-ray image with the rotation of the support unit is calculated using a function that represents the correspondence between the rotation angle of the support unit and the amount of movement, and the calculated movement A correction unit that corrects the X-ray image using a quantity;
A display control unit for displaying the corrected X-ray image on the display unit ,
The function is such that the amplitude representing the change in the movement amount corresponding to the change in the rotation angle depends on the distance between the isocenter and a predetermined point on the line connecting the X-ray tube and the center of the X-ray detector. Are different,
The correction unit calculates a plurality of movement amounts using a plurality of functions having different amplitudes, corrects the X-ray image using each of the calculated plurality of movement amounts,
The display controller, X-rays diagnostic apparatus according to claim and the view by the display unit, respectively corrected plurality of X-ray image by using a plurality of moving amount. The X-ray diagnostic apparatus according to claim 1 , wherein the display control unit extracts a central region from each of the plurality of X-ray images, and displays the extracted central regions side by side on the display unit. A selection unit that selects a predetermined X-ray image from a plurality of X-ray images displayed on the display unit by the display control unit;
The display controller, X-rays diagnostic apparatus according to claim 1 or 2, characterized in that displaying the entire central region or X-ray image of the X-ray image selected by the selection unit on the display unit. The X-ray diagnostic apparatus according to claim 3 , wherein the selection unit receives selection of the predetermined X-ray image from an operator. The X-ray diagnosis apparatus according to claim 3 , wherein the selection unit detects an operator's line-of-sight direction and selects an X-ray image positioned in the detected line-of-sight direction as the predetermined X-ray image. Wherein the correction unit, the X-ray image newly captured by the imaging unit, claims 3 to, characterized in that to correct by using the function used for correction of the X-ray image selected by the selection unit The X-ray diagnostic apparatus according to any one of 5 . The X acquired from an X-ray diagnostic apparatus that collects an X-ray image in which an object is depicted by rotating a support portion that supports an X-ray tube that irradiates X-rays and an X-ray detector that detects X-rays A storage unit for storing line images;
The amount of movement of the object that moves in the X-ray image with the rotation of the support unit is calculated using a function that represents the correspondence between the rotation angle of the support unit and the amount of movement, and the calculated movement A correction unit that corrects the X-ray image using a quantity ,
The function is such that the amplitude representing the change in the movement amount corresponding to the change in the rotation angle depends on the distance between the isocenter and a predetermined point on the line connecting the X-ray tube and the center of the X-ray detector. Are different,
The correction unit calculates a plurality of movement amounts using a plurality of functions having different amplitudes, corrects the X-ray image using each of the calculated plurality of movement amounts,
The display controller, an image processing apparatus according to claim and the view by the respective plurality of X-ray image corrected by using a plurality of moving amount to the display unit.

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