X-ray diagnosis apparatus and control method for x-ray diagnosis apparatus

Abstract

To suppress halation in X-ray images and exposure to a subject while reducing the operational burden of adjusting an X-ray diaphragm or a compensating filter, even when moving a top panel or imaging system during X-ray fluoroscopy or X-ray imaging.SOLUTION: An X-ray diagnosis apparatus according to one embodiment comprises a top panel, an imaging system, a compensating filter, a setting unit, and a tracking control unit. A subject is placed on the top panel. The imaging system includes an X-ray tube and an X-ray detector. The compensating filter attenuates X-rays emitted from the X-ray tube toward the subject, and is configured to be movable in position relative to the X-ray tube. The setting unit sets an initial position of the compensating filter relative to the X-ray tube so as to cover a predetermined site of the subject. The tracking control unit moves the position of the compensating filter relative to the X-ray tube from the initial position so as to track the predetermined site such that the compensating filter continues to cover the predetermined site of the subject when at least one of the top panel and the imaging system is moved.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to an X-ray diagnostic apparatus and a control method for an X-ray diagnostic apparatus.

Background Art

[0002] There are various types of X-ray diagnostic apparatuses, such as general X-ray imaging apparatuses and X-ray TV apparatuses. Among these, the general X-ray imaging apparatus has a relatively simple configuration and is, for example, an apparatus for performing X-ray imaging of the chest or the like. In addition to being able to acquire X-ray imaging images as still images, the X-ray TV apparatus is configured to be able to acquire X-ray fluoroscopic images as moving images so that image-guided therapy using a medical device such as a catheter, that is, IVR (Interventional Radiology), can be performed.

[0003] Many of these X-ray diagnostic apparatuses are provided with devices for controlling the irradiation area and dose of X-rays, such as an X-ray aperture device and a compensation filter device, in the vicinity of the X-ray tube. The X-ray aperture device is a device that forms an aperture through which X-rays pass using an aperture formed of a member such as lead, and irradiates only a desired area of the subject with the X-ray device through the aperture. On the other hand, the compensation filter device is a device that suppresses halation or suppresses exposure to the subject using a compensation filter that reduces X-rays.

[0004] On the other hand, an X-ray diagnostic apparatus, for example, an X-ray TV apparatus, is configured such that a top plate on which a subject is placed and an imaging system including an X-ray tube and an X-ray detector can be moved during X-ray fluoroscopy or X-ray imaging. By a user such as a doctor or a technician moving the top plate or the imaging system, a desired area of the subject can be fluoroscoped or imaged.

[0005] However, when the top plate or the imaging system is moved during fluoroscopy or X-ray imaging, the aperture position of the X-ray diaphragm and the position of the compensating filter, which have been preset, will also move. Therefore, each time the top plate or the imaging system is moved, the user needs to readjust the aperture position of the X-ray diaphragm and the position of the compensating filter, and these readjustments have imposed an operational burden on the user.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to reduce the operational burden related to the adjustment of the X-ray diaphragm and the compensating filter, and to suppress halation of the X-ray image and exposure to the subject, even when the top plate or the imaging system is moved during fluoroscopy or X-ray imaging. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problems. The problems corresponding to the effects of each configuration shown in each of the embodiments described below can also be regarded as other problems.

Means for Solving the Problems

[0008] An X-ray diagnostic apparatus according to an embodiment includes a top plate, an imaging system, a compensation filter, a setting unit, and a tracking control unit. The top plate is where the subject is placed. The imaging system includes an X-ray tube and an X-ray detector. The compensation filter is configured to attenuate the X-ray irradiated from the X-ray tube toward the subject and to be movable in position with respect to the X-ray tube. The setting unit sets an initial position of the compensation filter with respect to the X-ray tube so as to cover a predetermined part of the subject. The tracking control unit moves the position of the compensation filter with respect to the X-ray tube from the initial position to follow the predetermined part when at least one of the top plate and the imaging system moves so that the compensation filter continuously covers the predetermined part of the subject.

Brief Description of the Drawings

[0009]

Figure 1

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of an X-ray diagnostic apparatus and a control method of the X-ray diagnostic apparatus will be described in detail with reference to the drawings.

[0011] (First Embodiment) FIG. 1 is a schematic diagram showing a configuration example of an X-ray diagnostic apparatus 1 according to the first embodiment. FIG. 1 is an example of an X-ray diagnostic apparatus 1 that performs X-ray imaging on a subject P in a lying position. Note that the X-ray diagnostic apparatus 1 includes a general imaging apparatus, an X-ray fluoroscopy apparatus, an X-ray angiography apparatus, an X-ray TV apparatus, and the like. Further, the X-ray diagnostic apparatus 1 may be, for example, an X-ray fluoroscopic diagnostic apparatus used in a gastrointestinal contrast examination or the like, a cardiovascular X-ray fluoroscopic diagnostic apparatus used in an angiography examination or the like. Hereinafter, as shown in FIG. 1, the central axis in the X-ray irradiation direction is defined as the Z axis, the axis in the longitudinal direction of the top plate 51 that is perpendicular to the Z axis is defined as the Y axis, and the axis in the short-side direction of the top plate 51 that is perpendicular to the Z axis and the Y axis is defined as the X axis.

[0012] As shown in FIG. 1, the X-ray diagnostic apparatus 1 includes an imaging apparatus 10 and a console 20 as an example of an image processing apparatus. The imaging apparatus 10 includes an X-ray irradiation apparatus 30, an X-ray detector 34, a support frame 35, and a bed 50.

[0013] The X-ray irradiation apparatus 30 includes an X-ray tube 31, an X-ray aperture device 32, and a compensation filter device 33. The X-ray tube 31 is a vacuum tube that irradiates thermoelectrons from a cathode (filament) toward an anode (target) by applying a high voltage from a high voltage device 41. The X-rays generated by the X-ray tube 31 are irradiated onto the subject P.

[0014] The X-ray aperture device 32 is provided between the X-ray tube 31 and the subject P, and shapes the irradiation range of X-rays on the detection surface of the X-ray detector 34. The X-ray aperture device 32 has a plurality of aperture vanes that can move independently. Note that the plurality of aperture vanes provided in the X-ray aperture device 32 are also simply referred to as X-ray apertures. The X-ray aperture forms a movable opening, thereby limiting the irradiation range of the X-rays irradiated from the X-ray tube 31 toward the subject P to the range defined by the opening. In addition, the X-ray aperture device 32 is configured to be movable in position with respect to the X-ray tube 31. The X-ray aperture controller 42 can move the opening of the X-ray aperture in order to adjust the irradiation range of the X-rays. The plurality of aperture vanes are formed of, for example, lead that shields X-rays, and can move in the X-axis direction or the Y-axis direction orthogonal to the irradiation direction of the X-rays.

[0015] FIG. 2(a) is an example of an X-ray aperture. In FIG. 2(a), the X-ray aperture device 32 has a pair of aperture vanes 321c and 321d that narrow the X-rays spreading in the X-axis direction, and a pair of aperture vanes 321a and 321b that narrow the X-rays spreading in the Y-axis direction. Note that the X-ray aperture controller 42 may control the aperture vanes of the X-ray aperture device 32 asymmetrically in each direction, or may control each pair of aperture vanes symmetrically. For example, the X-ray aperture controller 42 may control so that all the aperture vanes move independently, or may control so that the two pairs of aperture vanes move symmetrically left and right and symmetrically up and down. In addition, the X-ray aperture may have a multilayer structure in which a plurality of the above-described aperture vanes are provided in the Z-axis direction.

[0016] The compensation filter device 33 is provided between the X-ray aperture device 32 and the subject P and has one or more compensation filters that can move independently. The compensation filter attenuates the X-rays irradiated from the X-ray tube 31 toward the subject P and is configured to be movable in position with respect to the X-ray tube 31. The compensation filter controller 43 can move the position of the compensation filter with respect to the X-ray tube 31. The compensation filter is formed of, for example, a metal plate having a rectangular shape, a semi-circular shape, an elliptical shape, etc., and is movable in a direction orthogonal to the X-ray irradiation direction.

[0017] FIG. 2(b) is an example of the compensation filter device 33. In FIG. 2(b), the compensation filter device 33 has two compensation filters 331a and 331b. In the initial state, for example, the longitudinal directions of the rectangular shapes of the compensation filters 331a and 331b are arranged parallel to each other. The compensation filter device 33 can be translated in the X-axis direction or the Y-axis direction orthogonal to the X-ray irradiation direction by moving both ends of the compensation filters 331a and 331b equidistantly from each other. Further, the compensation filter device 33 can be rotationally translated in the θ direction or the φ direction on a plane orthogonal to the X-ray irradiation direction by moving both ends of the compensation filters 331a and 331b by different distances from each other. Also, in FIG. 2(b), there are two compensation filters, but the number of compensation filters may be one or three or more.

[0018] The X-ray detector 34 includes, for example, a flat panel detector (FPD) having a plurality of X-ray detection elements arranged two-dimensionally, and an analog-to-digital converter (A / D converter) that converts an electrical signal into digital data. The X-ray detector 34 detects the X-rays generated from the X-ray tube 31, irradiated onto the subject P, and transmitted through the subject P. The X-ray detector 34 provides X-ray image data such as fluoroscopic imaging data generated by X-ray fluoroscopic imaging that captures in real time a time-series continuous X-ray image (frame image) based on the detected X-rays, and simple imaging data generated by simple X-ray imaging that captures one X-ray image, etc., to the console 20.

[0019] The support frame 35 movably supports the X-ray irradiation device 30 and the X-ray detector 34 arranged opposite to each other. Here, a configuration including at least the X-ray tube 31 and the X-ray detector 34 is referred to as an imaging system 36. The imaging system 36 can also be configured to include the X-ray irradiation device 30, the X-ray detector 34, and the support frame 35. The imaging system controller 44 can move the imaging system 36, for example, in the longitudinal direction (Y-axis direction) of the hospital bed 50. Further, the imaging system controller 44 can move the X-ray irradiation device 30 in the vertical direction.

[0020] The hospital bed 50 is supported on the floor surface and has a top plate 51 (also referred to as a lying table) on which the subject P is placed. The top plate 51 has the subject P placed thereon. The subject P is arranged between the X-ray irradiation device 30 and the X-ray detector 34 during X-ray imaging. The hospital bed controller 52 can move the top plate 51 on which the subject P lies, relative to the main body of the hospital bed 50 that houses the X-ray detector 34, for example, in the short side direction (X-axis direction). Further, the hospital bed controller 52 can move the hospital bed 50 in sliding (X and Y-axis directions), vertical (Z-axis direction), and rolling motions.

[0021] The controller 60 has at least a CPU (Central Processing Unit) and a memory (not shown), and is controlled by the processing circuit 21 of the console 20 to comprehensively control each component such as the high-voltage device 41, the X-ray aperture controller 42, the compensation filter controller 43, the imaging system controller 44, and the hospital bed controller 52 of the imaging device 10.

[0022] On the other hand, the console 20, as an example of an image processing device, has a processing circuit 21, a storage circuit 22, a display 23, an operation interface 24, and a communication interface 25. Note that the console 20 does not necessarily need to be provided independently, and the functions of the processing circuit 21 and the storage circuit 22 may be respectively assumed by the processor and the storage circuit of the controller 60 of the imaging device 10.

[0023] The communication interface 25 implements various information communication protocols according to the form of the network. The communication interface 25 has a function of performing communication control according to various protocols and connecting to the network in a wired or wireless manner. The communication interface 25 can, for example, exchange various data between the network and the memory circuit 22.

[0024] The operation interface 24 includes an input device that can be operated by the user and an input circuit that inputs a signal from the input device. The input device is realized, for example, by an operation console, a joystick, a trackball mouse, a keyboard, a touch panel that performs an input operation by touching an operation surface, a touch screen in which a display screen and a touch pad are integrated, a non-contact input circuit using an optical sensor, a voice input circuit, and the like.

[0025] Here, with reference to FIG. 3, an example of a switch for operating the X-ray aperture and the compensation filter attached to the operation interface 24 will be described. When the top plate 51 or the imaging system 36 is moved during X-ray fluoroscopy or X-ray imaging, the preset aperture position of the X-ray aperture and the position of the compensation filter will also move. Therefore, each time the top plate 51 or the imaging system 36 is moved, the user has to readjust the position of the X-ray aperture and the position of the compensation filter.

[0026] The operation interface 24 is provided with a compensation filter 331 and a switch for controlling the movement of the X-ray aperture.

[0027] The switches 241 and 242 for setting the position of the compensation filter are each switches with knobs. By the user operating the knobs forward and backward, left and right, and rotating them, the compensation filter can be manually moved. When the user operates the knobs of the switches 241 and 242 for setting the position of the compensation filter forward and backward, left and right, and rotating them, the compensation filters 331a and 331b in Fig. 2(b) move forward and backward, left and right, and rotate according to the amount of the operation. Also, by operating the knobs of the switches 241 and 242 forward and backward, left and right, and rotating them, the initial position of the follow-up operation of the compensation filter can be manually set.

[0028] Note that in Fig. 3, there are two compensation filters, and the case where there are two switches 241 and 242 for setting the positions of the two compensation filters so that each compensation filter can be manually operated is illustrated. However, the number of switches for the compensation filter is not limited. The switch for setting the position of the compensation filter may be one or three or more according to the number of each compensation filter.

[0029] Also, the switch 243 for following the compensation filter is a slide-type switch that can be set to manual start, follow-up stop, and automatic start. When the user slides it and performs an operation to set it to any of manual start, follow-up stop, and automatic start, the operation mode of following the compensation filter is set according to the operation for the compensation filter.

[0030] The switches 244 and 245 for setting the position of the X-ray aperture are also, for example, switches with knobs respectively. By the user operating the knobs back and forth and left and right, the X-ray aperture can be manually moved. When the user operates the knobs of the switch 244 for setting the position of the X-ray aperture back and forth and left and right, the aperture vanes 321a and 321c in Fig. 2(a) open or close back and forth and left and right according to the amount of the operation. Also, when the user operates the knobs of the switch 245 for setting the position of the X-ray aperture back and forth and left and right, the aperture vanes 321b and 321d in Fig. 2(a) open or close back and forth and left and right according to the amount of the operation. Further, by operating the knobs of the switches 244 and 245 back and forth and left and right, the initial position of the follow-up operation of the X-ray aperture can be manually set.

[0031] In addition, in Fig. 3, two switches are illustrated for setting the position of the X-ray aperture, but the number of switches for the X-ray aperture is not limited. The number of switches for setting the position of the X-ray aperture may be one, or three or more. When there is one switch for setting the position of the X-ray aperture, the X-ray aperture may be moved back and forth and left and right while maintaining the opening of the X-ray aperture.

[0032] Also, the switch 246 for following the X-ray aperture is a slide-type switch that can be set to manual start, follow-up stop, and automatic start. When the user slides it and performs an operation to set it to any one of manual start, follow-up stop, and automatic start, the follow-up operation mode of the X-ray aperture is set according to the operation.

[0033] Note that the settings for manual start, follow-up stop, and automatic start are not limited to the follow-up switch 243 for the compensation filter and the follow-up switch 246 for the X-ray aperture described above. For example, they may be set by hard buttons or soft buttons arranged on the console 20. Alternatively, they may be set by pressing an existing button twice or holding it down without arranging a new dedicated button. Further, they may be set by pressing in the switches 241 and 242 for setting the position of the compensation filter and the switches 244 and 245 for setting the position of the X-ray aperture. Additionally, the settings for manual start, follow-up stop, and automatic start may be made using voice recognition or the movement of the user's line of sight as a trigger.

[0034] The display 23 is constituted by a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display, for example. The display 23 displays an X-ray fluoroscopic image, an X-ray radiographic image, a minimap, etc. generated according to the control of the processing circuit 21. Note that the minimap is an example of a schematic diagram. The schematic diagram may be any diagram that schematically displays the compensation filter and is not limited to the minimap.

[0035] The display 23 may use the entire surface of the display as a display window, or may use a part of the display as a display window, or both may be made switchable. Further, the display 23 may display an X-ray fluoroscopic image or an X-ray radiographic image and a minimap side by side in the display window. Note that the display 23 may further display a screen related to patient information and various inputs.

[0036] The memory circuit 22 is constituted by a storage medium readable by a processor, such as a semiconductor memory element like a RAM (Random Access Memory) or a flash memory, a hard disk, an optical disk, etc. The memory circuit 22 may be constituted by a portable medium such as a USB (Universal Serial Bus) memory, a DVD (Digital Video Disk), etc. The memory circuit 22 stores various processing programs used in the processing circuit 21, data necessary for program execution, etc. Further, the memory circuit 22 stores various data such as imaging conditions related to X-ray imaging or fluoroscopic X-ray imaging, and image data of fluoroscopic X-ray images or X-ray images.

[0037] The processing circuit 21 has a processor and realizes each function described later by software processing by executing a program stored in the memory circuit 22. Further, the processing circuit 21 comprehensively controls each component of the imaging apparatus 10 via the controller 60.

[0038] As shown in FIG. 1, the processing circuit 21 realizes each function of an initial position setting function F01, a follow start determination function F02, a follow control function F03, a display control function F04, and an image generation function F05. Note that the display control function F04 is not essential and will be described later in the second embodiment. The operation examples of each function of the processing circuit 21 will be described with reference to the flowchart of FIG. 4 and FIGS. 5 to 11.

[0039] In step ST100, X-ray fluoroscopy or X-ray imaging is started. For example, based on the imaging conditions stored in the memory circuit 22 in advance according to the imaging conditions specified by the user via the operation interface 24, the diagnostic site of the subject P, the examination content, the examination purpose, the examination protocol, etc., X-ray fluoroscopy or X-ray imaging is performed. The image generation function F05 generates a fluoroscopic X-ray image or an X-ray image based on the X-ray data acquired by the X-ray detector 34.

[0040] In step ST101, it is selected whether to perform the tracking process of the compensation filter 331. For example, it is selected by the user via the operation interface 24.

[0041] In step ST101, when the tracking process of the compensation filter is performed (that is, in the case of YES), the process proceeds to step ST102. In step ST101, when the tracking process of the compensation filter is not performed (that is, in the case of NO), the process proceeds to step ST106. In step ST106, the user manually moves the compensation filter, for example, via the switches 241 and 242 for setting the position of the compensation filter of the operation interface 24.

[0042] In step ST102, the initial position setting function F01 sets the initial position of the compensation filter with respect to the X-ray tube 31 so as to cover a predetermined part of the subject P. The initial position of the compensation filter may be set manually, semi-automatically, or automatically. When manually setting the initial position of tracking, the user manually sets the initial position of the compensation filter, for example, via the switches 241 and 242 for setting the position of the compensation filter of the operation interface 24. The user manually arranges the compensation filter at an anatomically appropriate position, for example, under fluoroscopy.

[0043] FIG. 5 is an explanatory diagram of the semi-automatic setting of the initial position of the compensation filter. FIG. 5 is an example of an examination including the lungs in an X-ray image, and the region of interest ROI is a region excluding the lungs. As shown in FIG. 5, for example, the user sets a line segment for an X-ray fluoroscopic image or an X-ray radiographic image of the subject P. The user may set the line segment using, for example, the mouse of the operation interface 24. Further, the user may change the position of the line segment using a GUI function that can move or rotate the line segment set for the X-ray fluoroscopic image or the X-ray radiographic image.

[0044] The user can semi-automatically set the position of the compensation filter by using the set line segment. For example, the user can select one of the regions divided by the line segment, and the initial position of the compensation filter may be set in the region selected by the user. The user may select, for example, one of the regions divided by the line segment as the region where the compensation filter is to be placed by double-clicking or the like using the mouse or touch panel of the operation interface 24.

[0045] Note that the initial position of the compensation filter may also be determined according to the imaging conditions set at the start of imaging. If the compensation filter is pre-placed at a suitable position according to the imaging conditions, the movement of the compensation filter can be a fine adjustment. On the other hand, before placing the compensation filter, it is not necessary for the compensation filter to appear in the fluoroscopic X-ray image or the X-ray image. That is, the compensation filter may not be set before the start of fluoroscopic X-ray or X-ray imaging.

[0046] Also, the initial position setting function F01 may automatically set the initial position of the compensation filter based on the set line segment for the fluoroscopic X-ray image or the X-ray image of the subject P. For example, the initial position setting function F01 may analyze and determine the region to be covered by the compensation filter from the luminance values of the regions of the fluoroscopic X-ray image or the X-ray image divided by the line segment, and automatically set the initial position of the compensation filter so as to cover the region. In FIG. 5, the initial position of the compensation filter is automatically set so as to cover the brighter region. Note that when the black and white of the fluoroscopic X-ray image or the X-ray image is displayed in reverse, the initial position of the compensation filter may be automatically set so as to cover the darker region.

[0047] FIG. 6 is an explanatory diagram of the automatic setting of the initial position of the compensation filter. As shown in FIG. 6, the initial position setting function F01 uses at least one of the result of image recognition for the fluoroscopic X-ray image or the radiographic X-ray image of the subject P, and for example, the imaging conditions, to determine an anatomical site where exposure should be reduced or a suppression site where halation should be suppressed, and sets the initial position of the compensation filter so that the determined anatomical site or suppression site is covered by the compensation filter.

[0048] Further, the initial position of the compensation filter may be set according to the anatomical site or the suppression site. For example, the initial position setting function F01 may detect the position of the lung base or the position of the diaphragm based on image analysis of the fluoroscopic X-ray image or the radiographic X-ray image, determine the position of the lung from the position of the lung base or the diaphragm, and set the initial position of the compensation filter so that the determined position of the lung is covered by the compensation filter.

[0049] Also, the initial position setting function F01 may set the initial position of the compensation filter based on the imaging conditions set at the start of imaging.

[0050] In step ST103, the tracking start determination function F02 starts the tracking process of the compensation filter. The tracking start determination function F02 determines the start of the tracking process based on at least one of the fluoroscopic operation state of the subject P and the fluoroscopic image of the subject P. The tracking process of the compensation filter will be described with reference to FIG. 7. The tracking process of the compensation filter may be started manually or automatically.

[0051] In the case of manual start, for example, when the user operates to set the tracking switch 243 of the compensation filter 331 to manual start, the tracking process of the compensation filter 331 is started (manual start 1 in FIG. 7).

[0052] In the case of automatic start, the follow start determination function F02 detects that at least one of the top plate 51 and the imaging system 36 has moved during the X-ray fluoroscopy period, and starts the follow-up process in response to the detection of the movement. For example, the follow start determination function F02 may start the follow-up process when the compensation filter has not been manually moved for a predetermined period after the X-ray fluoroscopy is started (automatic start 1 in FIG. 7). Further, the follow start determination function F02 may start the follow-up process when the X-ray fluoroscopy continues for a predetermined period in a state where the top plate 51 and the imaging system 36 are not moved (automatic start 2 in FIG. 7).

[0053] When the X-ray fluoroscopy is operating in the pulse fluoroscopy mode, the follow start determination function F02 may start the follow-up process when the pulse rate is switched (automatic start 3 in FIG. 7). For example, when positioning at a low pulse rate and switching to a high pulse rate for imaging, or when positioning at an initially set pulse rate according to the imaging conditions and switching to a low pulse rate for imaging to reduce exposure, etc., the follow-up process may be started by determining the timing of the start of imaging when the pulse rate is switched.

[0054] When the dose of the X-ray fluoroscopy is switched, the follow start determination function F02 may start the follow-up process (automatic start 4 in FIG. 7). For example, when starting X-ray fluoroscopy with a low dose setting and switching to a high dose setting for imaging, or when starting X-ray fluoroscopy with a dose setting initially set for a predetermined examination and switching to a low dose setting for imaging to reduce exposure, etc., the follow-up process may be started by determining the timing of the start of imaging when the dose of the X-ray fluoroscopy is switched.

[0055] In addition, when a predetermined medical device is detected in the LIH (Last Image Hold) image of the first fluoroscopy, the tracking start determination function F02 may start the tracking process at the start of the second fluoroscopy following the first fluoroscopy (automatic start 5 in FIG. 7). Also, when a predetermined organ or tissue is detected in the LIH (Last Image Hold) image of the first fluoroscopy, the tracking start determination function F02 may start the tracking process at the start of the second fluoroscopy following the first fluoroscopy (automatic start 6 in FIG. 7).

[0056] When tracking is started in step ST103, in the next step ST104, the tracking process of the compensation filter is executed. When at least one of the top plate 51 and the imaging system 36 moves, the tracking control function F03 moves the position of the compensation filter with respect to the X-ray tube 31 from the initial position so that the compensation filter continues to cover a predetermined part of the subject P, and makes the compensation filter follow the predetermined part.

[0057] FIG. 8 is an explanatory diagram of the tracking process of the compensation filter 331 when the imaging system 36 moves in the Y-axis direction. As shown in FIG. 8, when the compensation filter 331 is initially set to the lungs, when the imaging system 36 moves in the Y-axis direction, the tracking control function F03 moves the position of the compensation filter 331 with respect to the X-ray tube 31 so that the compensation filter 331 continues to cover the lungs, and makes the compensation filter 331 follow the lungs.

[0058] FIG. 9 is an explanatory diagram of the tracking process of the compensation filter 331 when the top plate 51 moves in the X-axis direction. As shown in FIG. 9, when the compensation filter 331 is initially set to the lungs, when the top plate 51 moves in the X-axis direction, the tracking control function F03 moves the position of the compensation filter 331 with respect to the X-ray tube 31 so that the compensation filter 331 continues to cover the lungs, and makes the compensation filter 331 follow the lungs.

[0059] Further, the tracking control function F03 may perform tracking processing by an operation reflecting TOD (Table to Object Distance), which is the distance between a predetermined part of the subject P and the top plate 51. FIG. 10 is an explanatory diagram of TOD, which is the distance between a predetermined part of the subject P indicated by a star mark and the top plate 51. As shown in FIG. 10, based on the angle at which the X-rays irradiated from the X-ray tube 31 enter the X-ray detector 34, a movement amount D' reflecting TOD is calculated. Further, in addition to the movement in the X-axis direction and the Y-axis direction, it is also possible to calculate the movement amount D' reflecting TOD, taking into account the rotation of the imaging system 36. By calculating the movement amount D' reflecting TOD, as opposed to simply calculating the movement amount on the X-ray detector 34 based only on the movement amounts of the top plate 51 and the imaging system 36 (the movement amount D not reflecting TOD), highly accurate tracking processing becomes possible.

[0060] In step ST105, the tracking control function F03 stops the tracking process of the compensation filter. FIG. 11 is an explanatory diagram of the manual stop and automatic stop of the tracking process of the compensation filter.

[0061] The tracking process of the compensation filter may be stopped manually. For example, when the user operates to set the switch 243 for tracking of the compensation filter 331 to tracking stop, the tracking process of the compensation filter 331 is stopped (manual stop 1 in FIG. 11). When the tracking control function F03 receives an instruction to stop tracking during the tracking process, it may stop the tracking process while holding the position of the compensation filter at that time (manual stop 2 in FIG. 11). Further, when the tracking control function F03 receives an instruction to stop tracking during the tracking process, it may retract the compensation filter to a position circumscribing the field of view at that time (i.e., the X-ray irradiation range) and then stop the tracking process (manual stop 3 in FIG. 11).

[0062] Also, the tracking process of the compensation filter may be automatically stopped. For example, when the position of the compensation filter is manually adjusted during the tracking process, the tracking control function F03 stops the tracking process. In this case, the position of the compensation filter after adjustment may be used as a new initial position, and the tracking process may be restarted (automatic stop 1 in FIG. 11). Also, when a new initial position is erroneously set, the position of the compensation filter before adjustment may be stored so that it can be restored. Also, when the entire compensation filter goes out of the field of view during the tracking process, the tracking control function F03 may automatically stop the tracking process immediately or after a predetermined time has elapsed (automatic stop 2 in FIG. 11).

[0063] According to the X-ray diagnostic apparatus 1 according to the first embodiment, even when the top plate or the imaging system is moved during X-ray fluoroscopy or X-ray imaging, the operation burden related to the adjustment of the compensation filter can be reduced, and halation of the X-ray image and exposure to the subject can be suppressed.

[0064] (Second Embodiment) In addition to the first embodiment, the X-ray diagnostic apparatus 1 according to the second embodiment has a display control function F04 that causes the display 23 to display an X-ray fluoroscopic image or an X-ray radiographic image of the subject P and a minimap that schematically displays the compensation filter. Since the other configurations and functions are substantially the same as those of the X-ray diagnostic apparatus 1 according to the first embodiment, duplicate descriptions are omitted.

[0065] FIGS. 12 and 13 are explanatory diagrams of display examples of the display 23 and the minimap screen W3. As shown in FIGS. 12 and 13, on the display 23, the minimap screen W3 is displayed, for example, side by side with the screen W1 of the X-ray fluoroscopic image or the X-ray radiographic image and the screen W2 of the patient information.

[0066] In the minimap screen W3 of FIG. 12, the ranges where the compensation filters 331a and 331b are arranged are superimposed and displayed with respect to the maximum range of the X-ray aperture. In this case, the display control function F04 may display the compensation filters 331a and 331b on the minimap in different modes when the tracking process is being performed and when it is not being performed. For example, in the compensation filters 331a and 331b of FIG. 12, as shown by different hatchings before and during tracking, it may be displayed using differences in color, blinking, etc. so that the user can easily determine whether automatic tracking is in progress or not.

[0067] Also, the display control function F04 may display the compensation filters 331a and 331b on the minimap in a manner comparable to the position of the field of view. In the minimap screen W3 of FIG. 12, the position of the field of view is displayed by a dashed line. By displaying the position of the field of view with a dashed line, the position of the compensation filter can be confirmed within the maximum range of the X-ray aperture even when the field of view is out of the range.

[0068] Furthermore, the minimap screen W3 may be used for the confirmation operation of automatic tracking. For example, the position of the compensation filter on the minimap screen W3 may be moved by dragging the compensation filter displayed on the minimap screen W3 to the position where the user wants to place it with the mouse, or by clicking on the position where the user wants to place it after clicking on the compensation filter that the user wants to move.

[0069] In the minimap screen W3 shown in the upper right of FIG. 13, the relative positional relationship between the two compensation filters 331a and 331b is displayed without expressing the rotation radius during rotational movement. Also, the direction of the arrow in FIG. 13 indicates the moving direction when manually operating each of the compensation filters 331a and 331b.

[0070] In the minimap screen W3 shown in the lower right of FIG. 13, in addition to the relative positional relationship between the two compensation filters 331a and 331b and the moving directions of the respective compensation filters 331a and 331b, the rotation radii during the rotational movement of the respective compensation filters 331a and 331b are represented and displayed. In this way, when there are a plurality of compensation filters, the display control function F04 may display the compensation filters on the minimap so that the relative positional relationship between the plurality of compensation filters can be grasped.

[0071] Note that the minimap screen W3 may be one that represents and displays the relative positional relationship between the two compensation filters 331a and 331b and the rotation radii during the rotational movement of the respective compensation filters 331a and 331b. In this way, the display control function F04 may display at least one of the moving direction of the compensation filter and the rotation radius during the rotational movement of the compensation filter on the minimap.

[0072] According to the X-ray diagnostic apparatus 1 according to the second embodiment, the same effects as those of the X-ray diagnostic apparatus 1 according to the first embodiment can be obtained. Further, since the minimap is displayed side by side with the X-ray fluoroscopic image or the X-ray radiographic image, for the user, without being hindered from observing by the X-ray fluoroscopic image or the X-ray radiographic image, it becomes easy to grasp together the position of each compensation filter with respect to the position of the visual field, the relative positional relationship between the plurality of compensation filters, the moving direction of each compensation filter, and the rotation radius.

[0073] (Third Embodiment) The X-ray diagnostic apparatus 1 according to the first embodiment suppresses halation of the X-ray image and exposure to the subject by causing the compensation filter to follow when the top plate or the imaging system is moved during X-ray fluoroscopy or X-ray radiography. The X-ray diagnostic apparatus 1 according to the third embodiment is different from the first embodiment in that an X-ray aperture is caused to follow instead of the compensation filter. Since the other configurations and functions are substantially the same as those of the X-ray diagnostic apparatus 1 according to the first embodiment shown in FIG. 1, duplicate explanations are omitted. An operation example of each function of the processing circuit 21 will be described with reference to the flowchart of FIG. 14 and FIGS. 5 to 11.

[0074] In step ST200, fluoroscopy or radiography is started. Since step ST200 of the third embodiment is substantially the same as step ST100 of the first embodiment, duplicate explanations are omitted.

[0075] In step ST201, it is selected whether to perform the follow-up process of the X-ray aperture. For example, it is selected by the user via the operation interface 24.

[0076] In step ST201, when performing the follow-up process of the X-ray aperture (that is, in the case of YES), the process proceeds to step ST202. In step ST101, when not performing the follow-up process of the X-ray aperture (that is, in the case of NO), the process proceeds to step ST206. In step ST206, the user manually moves the X-ray aperture, for example, via the switches 244 and 245 for setting the position of the X-ray aperture of the operation interface 24.

[0077] In step ST202, the initial position setting function F01 sets the initial position of the X-ray aperture with respect to the X-ray tube 31 so that the X-ray irradiates a predetermined part of the subject through the aperture.

[0078] In step ST203, the follow-up start determination function F02 starts the follow-up process of the X-ray aperture. The follow-up start determination function F02 determines the start of the follow-up process based on at least one of the operation state of fluoroscopy of the subject P and the fluoroscopic image obtained by photographing the subject P. Note that the follow-up process of the X-ray aperture may be started manually or automatically. The follow-up start process of the X-ray aperture will be described with reference to FIG. 15.

[0079] In the case of manual start, for example, when the user performs an operation of setting the switch 246 for following the X-ray aperture to manual start, the follow-up process of the X-ray aperture is started (manual stop 1 in FIG. 15).

[0080] In the case of automatic start, the follow-up start determination function F02 detects that at least one of the top plate 51 and the imaging system 36 has been moved during the X-ray fluoroscopy period, and starts the follow-up process in response to the detection of the movement. For example, the follow-up start determination function F02 may start the follow-up process when the X-ray aperture has not been manually moved for a predetermined period after the start of the X-ray fluoroscopy (automatic stop 1 in FIG. 15).

[0081] Further, the follow-up start determination function F02 may start the follow-up process when the X-ray fluoroscopy continues for a predetermined period in a state where the top plate 51 and the imaging system 36 are not moved (automatic stop 2 in FIG. 15). Also, the follow-up start determination function F02 may start the follow-up process when the pulse rate is switched in the case where the X-ray fluoroscopy is operating in the pulse fluoroscopy mode (automatic stop 3 in FIG. 15). Further, the follow-up start determination function F02 may start the follow-up process when the dose of the X-ray fluoroscopy is switched (automatic stop 4 in FIG. 15).

[0082] Also, the follow-up start determination function F02 may start the follow-up process at the start of the second X-ray fluoroscopy following the first X-ray fluoroscopy when a predetermined medical device is detected in the LIH (Last Image Hold) image of the first X-ray fluoroscopy (automatic stop 5 in FIG. 15). Also, the follow-up start determination function F02 may start the follow-up process at the start of the second X-ray fluoroscopy following the first X-ray fluoroscopy when a predetermined organ or tissue is detected in the LIH (Last Image Hold) image of the first X-ray fluoroscopy (automatic stop 6 in FIG. 15).

[0083] In step ST204, when at least one of the top plate 51 and the imaging system 36 moves, the follow-up control function F03 moves the position of the X-ray aperture with respect to the X-ray tube from the initial position so as to continuously irradiate a predetermined part of the subject P with X-rays, and follows the predetermined part. Also, the follow-up control function F03 may perform the follow-up process by an operation that reflects the TOD (Table to Object Distance), which is the distance between a predetermined part of the subject P and the top plate.

[0084] In step ST205, the tracking control function F03 stops the process of tracking the X-ray aperture. The tracking process of the X-ray aperture is stopped manually. For example, when the user operates to set the switch 246 for tracking the X-ray aperture to tracking stop, the tracking process of the X-ray aperture is stopped.

[0085] According to the X-ray diagnostic apparatus 1 according to the third embodiment, even when moving the top plate or the imaging system during X-ray fluoroscopy or X-ray imaging, while reducing the operation burden related to the adjustment of the X-ray aperture, it is possible to suppress halation of the X-ray image and exposure to the subject.

[0086] Note that, as inspection examples to which the above-described embodiments are applied, inspection examples including the lungs in X-ray images such as bronchoscopy (that is, broncho), endoscopic retrograde cholangiopancreatography (that is, ERCP), etc. have been described. In addition, it is also applicable to inspection examples including direct lines on the side of the chest such as myelography (that is, myelography), colonoscopy, nerve root block, etc. in X-ray images.

[0087] According to at least one of the embodiments described above, even when moving the top plate or the imaging system during X-ray fluoroscopy or X-ray imaging, while reducing the operation burden related to the adjustment of the X-ray aperture or the compensation filter, it is possible to suppress halation of the X-ray image and exposure to the subject.

[0088] In the above embodiment, the term "processor" means, for example, a dedicated or general-purpose CPU (Central Processing Unit), GPU (Graphics Processing Unit), or an application-specific integrated circuit (ASIC), such as a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA), etc. When the processor is, for example, a CPU, the processor realizes various functions by reading and executing a program stored in a storage circuit. When the processor is, for example, an ASIC, instead of storing a program in a storage circuit, a function corresponding to the program is directly incorporated as a logic circuit in the circuit of the processor. In this case, the processor realizes various functions by hardware processing of reading and executing the program incorporated in the circuit. Alternatively, the processor can also realize various functions by combining software processing and hardware processing.

[0089] In the above embodiment, an example in which a single processor of a processing circuit realizes each function has been shown. However, a processing circuit may be configured by combining a plurality of independent processors, and each processor may realize each function. When a plurality of processors are provided, the storage circuit for storing a program may be provided individually for each processor, or one storage circuit may store programs corresponding to the functions of all processors collectively.

[0090] Note that the initial position setting function F01, the tracking start determination function F02, the tracking control function F03, the display control function F04, and the image generation function F05 in each embodiment are examples of the setting unit, the start determination unit, the tracking control unit, the display control unit, and the image generation unit in the claims, respectively.

[0091] Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 gist 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 its equivalent scope.

Explanation of Reference Numerals

[0092] 51... top plate, 31... X-ray tube, 32... X-ray aperture device, 33... compensation filter device, 34... X-ray detector, 35... support frame, 36... imaging system, 41... high voltage device, 42... X-ray aperture controller, 43... compensation filter controller, 44... imaging system controller, F01... initial position setting function, F02... tracking start determination function, F03... tracking control function, F04... display control function, F05... image generation function

Claims

1. A top plate on which a subject is placed, An imaging system including an X-ray tube and an X-ray detector, A compensation filter configured to attenuate X-rays irradiated from the X-ray tube toward the subject and to be movable in position with respect to the X-ray tube, A setting unit configured to set an initial position of the compensation filter with respect to the X-ray tube so as to cover a predetermined part of the subject, A tracking control unit configured to move the position of the compensation filter with respect to the X-ray tube from the initial position so as to follow the predetermined part and to continuously cover the predetermined part of the subject when at least one of the top plate and the imaging system moves, An X-ray diagnostic apparatus comprising the same.

2. A top plate on which a subject is placed, An imaging system including an X-ray tube and an X-ray detector, An X-ray aperture that forms a movable aperture and limits an irradiation range of X-rays irradiated from the X-ray tube toward the subject to a range defined by the aperture, the X-ray aperture being configured to be movable in position with respect to the X-ray tube, A setting unit configured to set an initial position of the X-ray aperture with respect to the X-ray tube so that the X-rays irradiate a predetermined part of the subject through the aperture, A tracking control unit configured to move the position of the X-ray aperture with respect to the X-ray tube from the initial position so as to follow the predetermined part and to continuously irradiate the predetermined part of the subject when at least one of the top plate and the imaging system moves, An X-ray diagnostic apparatus comprising the same.

3. A start determination unit configured to determine the start of the tracking process based on at least one of an operation state of X-ray fluoroscopy on the subject and a fluoroscopic image obtained by photographing the subject, The X-ray diagnostic apparatus according to claim 1, further comprising the same.

4. A start determination unit configured to determine the start of the tracking process based on at least one of an operation state of X-ray fluoroscopy on the subject and a fluoroscopic image obtained by photographing the subject, The X-ray diagnostic apparatus according to claim 2, further comprising the same.

5. The setting unit automatically sets the initial position of the compensation filter based on a line segment set for an X-ray fluoroscopic image or an X-ray radiographic image obtained by photographing the subject. The X-ray diagnostic apparatus according to claim 1.

6. The setting unit analyzes and determines a region to be covered by the compensation filter from luminance values of an image among regions of the X-ray fluoroscopic image or the X-ray radiographic image divided by the line segment, and automatically sets the initial position of the compensation filter so as to cover the region. The X-ray diagnostic apparatus according to claim 5.

7. The setting unit uses at least one of the X-ray fluoroscopic image or X-ray radiographic image obtained by photographing the subject and a preset imaging target site to determine an anatomical site where exposure should be reduced or a suppression site where halation should be suppressed, and sets the initial position of the compensation filter so that the determined anatomical site or the suppression site is covered by the compensation filter. The X-ray diagnostic apparatus according to claim 1.

8. The setting unit detects the position of the lung base or the position of the diaphragm based on image analysis of the X-ray fluoroscopic image or the X-ray radiographic image, determines the position of the lung from the position of the lung base or the diaphragm, and sets the initial position of the compensation filter so that the determined position of the lung is covered by the compensation filter. The X-ray diagnostic apparatus according to claim 7.

9. The setting unit sets the initial position of the compensation filter based on the imaging conditions set at the start of imaging. The X-ray diagnostic apparatus according to claim 1.

10. During the X-ray fluoroscopy period, the start determination unit detects that at least one of the top plate and the imaging system has been moved, and starts the tracking process in response to the detection of the movement. The X-ray diagnostic apparatus according to claim 3 or 4.

11. After the X-ray fluoroscopy is started, when the compensation filter has not been manually moved for a predetermined period, the start determination unit starts the tracking process. The X-ray diagnostic apparatus according to claim 3.

12. After the X-ray fluoroscopy is started, when the X-ray aperture has not been manually moved for a predetermined period, the start determination unit starts the tracking process. The X-ray diagnostic apparatus according to claim 4.

13. When the X-ray fluoroscopy continues for a predetermined period in a state where the top plate and the imaging system are not moved, the start determination unit starts the tracking process. The X-ray diagnostic apparatus according to claim 3 or 4.

14. When the X-ray fluoroscopy is operating in the pulse fluoroscopy mode, when the pulse rate is switched, the start determination unit starts the tracking process. The X-ray diagnostic apparatus according to claim 3 or 4.

15. When the dose of the X-ray fluoroscopy is switched, the start determination unit starts the tracking process. The X-ray diagnostic apparatus according to claim 3 or 4.

16. When a predetermined medical device is detected in the LIH (Last Image Hold) image of the first fluoroscopy, the start determination unit starts the tracking process at the start of the second fluoroscopy following the first fluoroscopy. The X-ray diagnostic apparatus according to claim 3 or 4.

17. When a predetermined organ or tissue is detected in the LIH (Last Image Hold) image of the first fluoroscopy, the start determination unit starts the tracking process at the start of the second fluoroscopy following the first fluoroscopy. The X-ray diagnostic apparatus according to claim 3 or 4.

18. When the position of the compensation filter is manually adjusted during the tracking process, the tracking control unit restarts the tracking process with the adjusted position of the compensation filter as a new initial position. The X-ray diagnostic apparatus according to claim 1.

19. When receiving an instruction to stop tracking during the tracking process, the tracking control unit stops the tracking process while holding the position of the compensation filter at its current position. The X-ray diagnostic apparatus according to claim 1.

20. When receiving an instruction to stop tracking during the tracking process, the tracking control unit retracts the compensation filter to a position circumscribing the current field of view and then stops the tracking process. The X-ray diagnostic apparatus according to claim 1.

21. When the entire compensation filter goes out of the field of view during the tracking process, the tracking control unit automatically stops the tracking process immediately or after a lapse of a predetermined time. The X-ray diagnostic apparatus according to claim 1.

22. The tracking control unit performs the tracking process by an operation reflecting the TOD (Table to Object Distance), which is the distance between the predetermined part of the subject and the top plate. The X-ray diagnostic apparatus according to claim 1 or 2.

23. A display; A display control unit that causes the display to display an X-ray fluoroscopy image or an X-ray radiography image of the subject and a schematic diagram schematically showing the compensation filter. The X-ray diagnostic apparatus further comprising: The X-ray diagnostic apparatus according to claim 1.

24. The display control unit causes the compensation filter to be displayed in the schematic diagram in different modes when the tracking process is being performed and when it is not being performed. The X-ray diagnostic apparatus according to claim 23.

25. The display control unit causes the compensation filter to be displayed in the schematic diagram in a manner comparable to the position of the field of view. The X-ray diagnostic apparatus according to claim 23.

26. When there are a plurality of the compensation filters, the display control unit causes the compensation filters to be displayed in the schematic diagram so as to be able to grasp the relative positional relationship between the plurality of compensation filters. The X-ray diagnostic apparatus according to claim 23.

27. The display control unit causes at least one of the moving direction of the compensation filter and the radius of rotation during rotational movement of the compensation filter to be displayed in the schematic diagram. The X-ray diagnostic apparatus according to claim 23.

28. A top plate on which a subject is placed, An imaging system including an X-ray tube and an X-ray detector, A compensation filter configured to attenuate X-rays irradiated from the X-ray tube toward the subject and to be movable in position with respect to the X-ray tube, A control method for an X-ray diagnostic apparatus, comprising: Setting an initial position of the compensation filter with respect to the X-ray tube so as to cover a predetermined part of the subject; When at least one of the top plate and the imaging system moves, moving the position of the compensation filter with respect to the X-ray tube from the initial position so that the compensation filter continuously covers the predetermined part of the subject and causing the compensation filter to follow the predetermined part. A control method for an X-ray diagnostic apparatus.

29. A top plate on which a subject is placed, An imaging system including an X-ray tube and an X-ray detector, An X-ray aperture that forms a movable aperture to limit an irradiation range of X-rays irradiated from the X-ray tube toward the subject to a range defined by the aperture, the X-ray aperture being configured to be movable in position with respect to the X-ray tube, A control method for an X-ray diagnostic apparatus, comprising: Setting an initial position of the X-ray aperture with respect to the X-ray tube so that X-rays irradiate a predetermined part of the subject through the aperture; When at least one of the top plate and the imaging system moves, moving the position of the X-ray aperture with respect to the X-ray tube from the initial position so that the X-rays continuously irradiate the predetermined part of the subject and causing the X-ray aperture to follow the predetermined part. A control method for an X-ray diagnostic apparatus.

Images