JP4495958B2 - X-ray diagnostic apparatus and X-ray imaging method - Google Patents

Description

  The present invention relates to an X-ray diagnostic apparatus and an X-ray imaging method, and more particularly to an X-ray diagnostic apparatus and an X-ray imaging method suitable for performing a leg imaging examination.

    An X-ray diagnostic apparatus is a modality that can be used for examination and diagnosis of various parts of a subject. One of examinations by this X-ray diagnostic apparatus is a leg imaging examination.

  In the lower limb contrast examination by the X-ray diagnostic apparatus, a contrast medium is injected into the artery from the buttocks of the subject, and X-ray imaging is performed so as to follow the flow of the contrast medium. Therefore, the shooting range covers a wide range from the vicinity of the pelvis to the toes, and it is not possible to obtain a whole image with one shot, so partial shooting is performed in several times, and then the images are pasted together In this way, an overall picture is obtained. However, since this imaging range includes regions of different sizes (thickness, length, etc.) such as thighs, knees, shins, and heels, the X-ray irradiation range is set to a size that can cover, for example, the vicinity of the pelvis. If, for example, the shin part is photographed in the state where it is left as it is, halation will occur and the image quality will be impaired.

  Therefore, in order to eliminate such inconvenience, conventionally, the opening in the width direction of the X-ray diaphragm device has been adjusted so that X-rays are not irradiated to the outer region of the contour of the subject.

Further, as shown in Japanese Patent Application Laid-Open No. 6-217973 (particularly, pages 21-22, FIG. 50), when performing moving imaging of the lower limb, the contour data of the subject corresponding to the position data of the bed by the press scan A method is also known in which a control table is created by extracting the information and the control table is referred to during X-ray imaging. That is, with reference to this control table, the opening in the width direction of the X-ray diaphragm device is controlled for each position of the bed, and as a result, X-rays are not irradiated to the outer region of the contour of the subject. there were. In this case, the opening degree of the X-ray diaphragm device in the length direction (that is, the body axis direction of the subject) was always constant.
Japanese Patent Laid-Open No. 6-217773

  However, in a wide range from the vicinity of the pelvis to the toes, the blood flow velocity is not constant, there are parts where the flow is slow and parts where the flow is fast, and there are also simple parts and complex parts of blood vessels running is there. For this reason, when moving imaging of the lower limb is performed with the opening degree in the length direction of the X-ray diaphragm device (that is, the direction of the lower limb of the subject) being constant, a part that is partially unsatisfactory diagnostically in the image obtained by imaging There was a problem that existed.

  For such a problem, it is also possible to adopt a method of increasing the number of imaging by narrowing the imaging interval in the direction of the lower limb of the subject. If this is done, the opening in the length direction of the X-ray diaphragm device will inevitably be reduced, leading to the solution of the above problem, but the operator has a display area for the captured image. Since the image must be taken while following the flow of the contrast agent in a narrowed state, the operation is complicated and enlarged.

  Therefore, the present invention provides an X-ray diagnostic apparatus and an X-ray imaging method that can perform X-ray imaging under optimum conditions following the flow of a contrast agent, reduce the burden on the operator, and improve operability. The purpose is to provide.

In order to achieve the above object, according to an aspect of the X-ray diagnostic apparatus of the present invention, an X-ray source that generates X-rays, an X-ray detector that detects the X-rays, the X-ray source, and The X-ray detector and the X-ray detector are arranged so that the X-ray detectors face each other and the top plate on which the subject is placed is positioned in a spatial space between the X-ray source and the X-ray detector. A holding means for holding a vessel, and one of the top plate and the holding means is moved relative to the other while the contrast medium is injected into the subject. A fluoroscopic imaging means for obtaining a fluoroscopic image by performing fluoroscopic imaging along the direction in which the contrast agent substantially flows, and at least imaging parameters necessary for the main imaging based on the fluoroscopic image obtained by the fluoroscopic imaging means, Imaging parameters set for each part that continues in the direction And a meter setting means, based on said imaging parameter, the in the direction of flow of the contrast agent is injected into the subject, the irradiation control means for controlling the irradiation range for the subject of the X-rays generated from the X-ray source And, based on the imaging parameters set by the imaging parameter setting means, while moving one of the top plate and the holding means relative to the other, And a main photographing means for performing the main photographing.

An X-ray imaging method according to the present invention includes an X-ray source that generates X-rays, an X-ray detector that detects the X-rays, the X-ray source and the X-ray detector facing each other, It is executed by an X-ray diagnostic apparatus comprising a holding means for holding the X-ray source and the X-ray detector so that the top plate is positioned in a spatial space between the X-ray source and the X-ray detector. a photographing method, while one is moved relative to the other the of said top plate and said holding means, and obtaining a fluoroscopic image by performing a fluoroscopic imaging, obtained by the fluoroscopic imaging fluoroscopy imaging parameters necessary for the present photographing based on the image, and setting for each portion continuous in the longitudinal direction of at least the top plate, on the basis of the imaging parameters, the X-ray to be generated from the previous SL X-ray source at least the irradiation elevation range And controlling the longitudinal direction of the serial top plate, based on the imaging parameters set by the photographing parameter setting means, one is moved relative to the other the of said top plate and said holding means while, characterized in that it comprises the steps of performing a pre-Symbol present photographing, the.

  It is possible to control the X-ray irradiation range so as to follow the flow of the contrast agent, and to obtain a good X-ray diagnostic image. In addition, the burden on the operator can be greatly reduced, and an X-ray diagnostic apparatus with good operability can be provided.

    Preferred embodiments of the X-ray diagnostic apparatus according to the present invention will be described below in detail with reference to the drawings.

  A first embodiment of the X-ray diagnostic apparatus according to the present invention will be described in detail with reference to FIGS.

  The X-ray diagnostic apparatus according to the first embodiment includes a holding device 10, an X-ray tube 20, an X-ray detector 30, and a control device 50.

  FIG. 1 is a perspective view showing a partial schematic configuration of a holding device 10 of the X-ray diagnostic apparatus. The holding device 10 includes a holding device main body 11, a C arm holding mechanism 12, a C arm 13, and a top plate holding mechanism 14. The main plate 15 is mainly composed.

  The holding device body 11 is fixed to the floor, and holds the C-arm holding mechanism 12 slidably in a direction substantially parallel to the floor (indicated by an arrow A in the figure). In the C arm holding mechanism 12, the C arm 13 can be rotated (indicated by an arrow B in the figure) on a plane substantially perpendicular to the floor with the attachment position to the C arm holding mechanism 12 as the center. At the same time, it is slidably mounted in the arc direction (indicated by an arrow C in the figure) and can be inclined with respect to a top plate 15 described later. Note that an X-ray tube 20 and an X-ray detector 30 described later are attached to the C arm 13 so as to face each other with the top plate 15 therebetween.

  On the other hand, the top plate holding mechanism 14 is held so as to be movable up and down (indicated by an arrow D in the drawing) and rotatable (indicated by an arrow E in the drawing) with respect to the holding device main body 11.

The top plate 15 is slidable in the width direction (indicated by an arrow F in the figure) and movable in the thickness direction (indicated by an arrow G in the figure). It is attached in a state. In addition, the top plate 15 can be rotated with respect to the top plate holding mechanism 14 about the central axis in the longitudinal direction (indicated by an arrow H in the drawing). The top plate 15 is for placing the subject P as shown in FIG.

  The X-ray tube 20 is attached to one end of the C-arm 13 held by the C-arm holding mechanism 12 so as to face the top plate 15 side. An X-ray diaphragm 21 and a compensation filter 22 are provided (see FIG. 2). The X-ray diaphragm 21 is for narrowing the irradiation range of the X-rays irradiated from the X-ray tube 20 to a desired range so that unnecessary portions of the subject are not irradiated with X-rays. As shown in Fig. 4, the diaphragm blades 21a to 21d made of a lead plate are combined in a cross-beam shape. Since the diaphragm blades 21a to 21d are individually driven by a servo motor via a rack and pinion mechanism or the like (not shown), the desired diaphragm blades 21a, 21b and 21c, 21d are brought into contact with and separated from each other to achieve desired irradiation. A range (shown by hatching in the figure, also referred to as an irradiation field or aperture) is formed. The compensation filter 22 is used to partially attenuate the X-ray dose in the X-ray irradiation range. The X-ray tube 20, the X-ray diaphragm 21 and the compensation filter 22 can be moved back and forth (indicated by an arrow I in the figure) from the side attached to the C arm 13 to the top plate 15 side.

  Furthermore, an X-ray detector 30 is attached to the other end of the C arm 13 so as to face the X-ray tube 20 with the top plate 15 interposed therebetween. For example, as shown in FIG. 2, the X-ray detector 30 includes an image intensifier (hereinafter abbreviated as II) 31 and an imaging tube or a solid-state imaging device (for example, Charge). A television camera 32 having a coupled device (CCD) is coupled via an optical system 33. I. An X-ray grid 34 is provided on the front surface of 31, that is, on the top plate 15 side. Where I.I. I. 31 receives X-rays irradiated from the X-ray tube 20 and transmitted through the subject P, and converts them into an optical image. This optical image is incident on the TV camera 32 via the optical system 33 and is transmitted to the TV video signal. Is converted to The X-ray grid 34 indicates that scattered X-rays generated by the subject P are I.D. I. This is to prevent the light from entering 31. Such an X-ray detector 30 can be moved back and forth (indicated by an arrow J in FIG. 1) from the attachment side to the C-arm 13 to the top plate 15 side.

  Next, the control device 50 which is one of the main components of the X-ray diagnostic apparatus along with the holding device 10 will be described with reference to FIG. In FIG. 2, together with the X-ray tube 20 and the X-ray detector 30 provided in the holding device 10, each device constituting the control device 50 is shown as a system diagram.

  In other words, the control device 50 includes a system controller 51 that plays a central role in comprehensively controlling the operation of the entire X-ray diagnostic apparatus, and a keyboard for an operator to give predetermined instructions to the system controller 51. Alternatively, an operation panel 52 having a pointing device such as a mouse or a trackball including a touch panel, a high voltage generator 53 for generating a high voltage to be applied to the X-ray tube 20, and an X-ray controller 54 for controlling the high-voltage generator 54 An X-ray diaphragm controller 55 that controls the amount of movement of the diaphragm blades 21a to 21d in order to obtain an irradiation range, that is, a desired opening of the X-ray diaphragm 21, a compensation filter controller 56 that controls the position of the compensation filter 22, and the like. The operation of the arm holding mechanism 12 and the C arm 13 held by the arm holding mechanism 12 and the top plate holding mechanism 14 and the support Like holding device controller 57 that controls the operation of the top plate 15 it is provided that.

  Further, the control device 50 includes I.I. I. Control I.31 I. A controller 58, a television camera controller 59 that controls the television camera 32, an image obtained from the television camera 32 or an image processed by an image processor 60 described later, an X-ray controller 54, an X-ray aperture controller 55, Is stored together with the X-ray control conditions by the compensation filter controller 56, the imaging position by the holding device controller 57, the image processing conditions in the image processor 60, and the like. An image processor 60 that performs gradation processing, spatial filter processing, or addition processing or subtraction processing on an image obtained in real time from the television camera 32, and an image obtained from the television camera 32 are displayed in real time. And a display device 62 for displaying an image processed by the image processor 60 is also provided.

  Further, the control device 50 determines an appropriate aperture position / size for the image stored in the image storage device 61 based on the position signal from the X-ray aperture controller 55 when the image is obtained. A diaphragm position / size / angle calculator 63 for calculating the height / angle and the like, and calculating an appropriate moving speed of the C-arm 13 for a plurality of parts from the moving point of the contrast agent of interest and the imaging position information, An imaging parameter storage 64 that stores this along with the aperture position, its size, and the imaging interval. In a predetermined imaging sequence, an appropriate moving speed of the C-arm 13 that is stored in the imaging parameter storage 64 from the position information at that time. An imaging parameter controller 65 for controlling the X-ray diaphragm controller 55, the holding device controller 57, and the like is also provided.

  An operation in the case of performing a lower limb contrast examination by the X-ray diagnostic apparatus configured as described above will be described below. Although directions are indicated by arrows in FIG. 2, the width direction of the subject P placed on the top 15 is represented by X, the body axis direction is represented by Y, and the thickness direction is represented by Z.

  First, fluoroscopic imaging is performed on the subject P over a wide range from the vicinity of the pelvis to the toes, and the opening degree of the X-ray diaphragm 21 is set for each region. The fluoroscopic imaging as a pre-scan using a contrast agent is performed, for example, by performing a bolus administration of a small amount of contrast agent on the lower limb of the subject and positioning for the main imaging by weak X-rays. In this case, since it is not possible to obtain an entire image of a desired diagnosis range by one imaging, the C-arm 13 (that is, the X-ray tube 20 and the X-ray detector 30) is kept with the top 15 being stationary, The top plate 15 is moved in the longitudinal direction (that is, the Y direction), and partial photographing is performed in several times, and then the whole image is obtained by pasting the images together. This moving operation is performed by moving the C arm holding mechanism 12 in the direction of arrow A shown in FIG. 1 via the holding device controller 57. Further, the rotation angle (see the direction of arrow B in FIG. 1) and the inclination angle (see the direction of arrow C in FIG. 1) of the C arm 13 with respect to the top 15 are set so that the desired part can be best depicted. .

  FIG. 4A shows an outline of the range of X-ray imaging of the subject P in the lower extremity contrast examination, and FIG. 4B shows a long image obtained by pasting images obtained by fluoroscopic collection in advance. The state when the opening degree of the X-ray diaphragm 21 is set for each region for the main imaging with respect to the scale-displayed image is shown.

  That is, first, a contrast medium is injected into the subject P shown in FIG. 4A, and the fluoroscopic collection is performed by dividing the range indicated by the arrow several times, and each fluoroscopic image is stored in the image storage 61. To remember. Next, the respective fluoroscopic images stored in the image storage device 61 are read out under the control of the system controller 51, and the processing is performed in the image processing device 60. As shown in FIG. Is displayed as a long picture of the lower limb.

  With respect to the fluoroscopic image displayed on the display device 62 or the fluoroscopic image of each imaging region of interest, the operator can perform actual imaging for each desired region by using a pointing device provided on the operation panel 52. The optimal size of the X-ray stop 21 is set. That is, over a wide range from the vicinity of the pelvis to the toes, depending on the region to be observed with particular interest, the size of each region, the flow of the contrast medium, etc. (Shooting range) is set as indicated by a dotted line in FIG.

  That is, in FIG. 4B, the opening of the X-ray diaphragm 21 is set to 1 at the imaging position 1, the opening of the X-ray diaphragm 21 is set to 2 at the subsequent imaging position 2, and the imaging is further performed. A state in which the opening degree of the X-ray diaphragm 21 is set to the state of n at the imaging position n is shown such that the opening degree of the X-ray diaphragm 21 is set to the state of 3 at the position 3. Here, the apertures 1, 2, 3,... N of the X-ray diaphragm 21 are not necessarily all different, and may be the same depending on the imaging position. In order to reduce the exposure, it is preferable that the imaging ranges are not overlapped as much as possible in the body axis direction (Y direction) of the subject P at adjacent imaging positions, but the flowing contrast agent is contained in the screen. Therefore, even if the imaging rate f (30 frames per second at the maximum, but can be changed to 15 frames or 7.5 frames depending on the setting) is adjusted according to the contrast medium speed λ. It is unavoidable that some overlap occurs.

  As described above, when the aperture is set for each imaging position by the pointing device, the movement amount in the x and y directions of the blades 21 a to 21 d constituting the X-ray aperture 21 is determined as the aperture position / size / angle calculator 63. The calculation result is stored in the imaging parameter storage 64.

  It is also possible to read out a plurality of X-ray fluoroscopic images obtained by fluoroscopy in advance from the image storage 61 and display them in a trace manner. By a feedback flow as shown in FIG. The rate f and the moving speed of the C arm 13 can be set.

  That is, as shown in FIG. 5 (a), an image that is fluoroscopically collected in a state in which a contrast medium has been injected into the subject in advance and stored in the image memory 61 is displayed as shown in FIG. 5 (b). Displayed as a trace image for each cine playback or set frame. FIG. 5 (a) schematically shows images from m frames to n frames stored in the image storage device 61. The shooting time of an image of m frames is Tm, and the collection position is lm. Yes, the collection time of an image of n frames is Tn, and the collection position is ln. Here, m <n, and the collection rate f is, for example, 30 fps.

  Next, as shown in FIG. 5B, the operator sequentially displays images on the display device 62, confirms the diffusion state of the contrast medium while viewing the images, and stops the desired image. Then, as shown by the dotted frame in FIG. 5 (c), the opening of the X-ray diaphragm 21 (positions of the blades 21a to 21d in the x and y directions) that is optimal for the actual photographing with respect to the image. Set. This setting is performed by operating the pointing device of the operation panel 52 to operate the X-ray aperture controller 55.

  Therefore, since the frame interval of the peak-traced image is m to n, the moving speed λ of the contrast agent can be found from the specified two pieces of position information and time information based on the collection rate f by the equation (1).

λ = (ln−lm) / (Tn−Tm) (1)
If the moving speed λ of the contrast medium is faster than the moving speed of the C-arm 13 at the time of imaging, the flow of the contrast medium may not be reflected on the screen. By increasing the size or increasing the imaging rate f and re-setting, the region that the doctor is particularly interested in observing is set as the imaging region, and the state in which the contrast medium flows throughout the region is entered. To shoot.

  At this time, an error (Δ) for combining the previous and subsequent images is automatically added when the entire image is displayed in a long size from the size of the X-ray diaphragm 21 set for each image. Further, the shooting elapsed times Tm and Tn and the shooting positions lm and ln are used as support information for determining the shooting interval K and the shooting rate f.

  By sequentially repeating this operation for each imaging region, various setting values such as the rotation angle, inclination angle, and speed, and the contrast are set for each imaging position over the entire imaging range, that is, according to the position of the C arm 13 with respect to the top 15. Imaging parameters (setting values) such as the speed of the agent are stored in the imaging parameter storage 64 as a storage table shown in FIG.

  When the aperture, imaging interval, and moving speed for each imaging region are determined through such preparatory work, actual imaging is performed. This imaging includes a mask sequence performed before injecting a contrast medium into a subject and a contrast sequence performed by injecting a contrast medium. That is, with respect to the subject before the contrast medium is injected by the mask sequence, for example, the pelvis is set so as to follow the aperture opening, the imaging rate, the moving speed, etc. determined by the above-described fluoroscopic collection under the control of the imaging parameter controller 65. A predetermined part is photographed from the direction toward the toe direction, and the obtained mask image is stored in the image memory 61 together with the position information.

  Thereafter, a contrast medium is injected into the subject, and imaging with a contrast sequence is performed under the control of the imaging parameter controller 65 in accordance with the direction of the contrast medium flow to obtain a contrast image. Note that information such as the moving speed of the C-arm 13 at the time of imaging and the elapsed time after injecting the contrast agent are sequentially supplied to the imaging parameter controller 65, so that the imaging parameter controller 65 is stored in the imaging parameter memory. 64. Control is performed so that shooting is performed under the conditions stored in 64.

  When a contrast image is obtained, the image is stored in the image memory 61 together with position information. Further, the image processor 60 reads out the previously captured mask image from the image memory 61 and the image processor 60 reads the contrast image. Is subtracted to obtain a subtraction image. The subtraction image is stored in the image memory 61 including the position information and is displayed on the display device 62 in real time. Needless to say, the contrast image and the mask image subjected to the subtraction process are images of the same part of the subject. Further, the subtraction image is an image in which the same background portion of the contrast image and the mask image is removed and only the portion where the contrast agent flows is displayed.

  As described above, in actual photographing, various setting values (imaging parameters) stored in the photographing parameter storage 64 can be read out, and a mask image and a contrast image can be obtained under the control of the system controller 51 according to the setting values. For example, an appropriate diagnostic image can be obtained for each imaging region while greatly reducing the burden on the operator.

  Such an operation procedure of the present embodiment is shown in a flowchart in FIG. 7, and will be described again along this flowchart.

  That is, as step S10, first, the position and angle of the C arm 13 are set to the initial position. Specifically, the position and angle of the C arm 13 with respect to the top plate 15 are detected to detect whether or not there is any deviation from the initial position, and if there is any deviation, it is corrected by the operation of the holding device controller 57. This instruction is given by the system controller 51. When the position and angle of the C-arm 13 are set, in step S20, the opening (blade 21a) of the X-ray diaphragm 21 at that position is determined from the set value (see FIG. 6) stored in the imaging parameter storage 64. ˜21d x, y position) is retrieved, and the X-ray diaphragm controller 55 is operated to set a predetermined opening. This is also done by the system controller 51. Subsequently, in step S30, the moving speed β of the C arm 13 at that position is retrieved from the setting value stored in the imaging parameter storage 64. The data of the opening degree of the X-ray diaphragm 21 and the moving speed β of the C arm 13 are transmitted to the imaging parameter controller 65 as step S40. Therefore, in step S50, based on the setting value stored in the imaging parameter storage unit 64, the main imaging is performed under the control of the imaging parameter controller 65 to obtain a mask image and a contrast image.

  When a contrast image is obtained in the actual shooting, the operator can continue to press a shooting button (not shown) provided on the operation panel 52 while watching the contrast image displayed on the display device 62 in real time. For example, the contrast image is taken by automatically moving the C-arm 13 following the flow of the contrast agent. However, when the follow-up of the contrast agent by automatic control deviates for some reason, the subsequent movement operation of the C-arm 13 is manually performed by operating a joystick (not shown) provided on the operation panel. In this case, only the control of the X-ray diaphragm 21 is automatically performed.

  Thus, according to the embodiment of the present invention, an operator's burden is greatly reduced, and an X-ray diagnostic apparatus with good operability is provided.

  As another embodiment of the present invention, based on the information of the setting value storage table (see FIG. 6) stored in the imaging parameter storage 64, as shown in FIG. The profile of the relationship between the position of the C arm 13 with respect to the moving speed of the contrast medium and the moving speed of the C arm 13 can be displayed as a diagnostic information.

  Also, an image useful for diagnosis is read out from the captured images stored in the image storage 61 and displayed on the display device 62 as shown in FIG. 9, and the contrast agent is superimposed on the display image. If the measurement start point and the measurement end point are displayed and the measured moving speed of the contrast agent is also displayed in characters, it is possible to provide information for reference at the time of diagnosis by a doctor in a timely manner.

  Further, as shown in FIG. 10A, a region of interest (ROI) is arbitrarily set on a long image using a pointing device provided on the operation panel 52, thereby subtraction of the portion. Images can be read from the image store 61 and displayed on the display device 62. And even if the part is composed of a plurality of images such as m1 and m2, the images may be displayed on the display device 62 in a connected form as shown in FIG. 10B. it can. Also in this case, it is possible to display the moving speed of the contrast agent in an overlapping manner.

  It is known that blood flow is slower at joints such as knees and heels, and blood flow velocity is slower than straight parts such as thighs and shins. ing. Therefore, when it is desired to particularly observe the condition of a joint part such as a knee or a heel, by designating that part in advance, when the X-ray imaging position reaches the designated position, the X-ray aperture control is performed. It is also possible for the device 55 to control the X-ray diaphragm 21 so as to have an opening (for example, a narrow opening) suitable for photographing a slow contrast medium flow at the site. Can be further reduced.

  In order to designate this specific part, a region to be particularly observed using a pointing device provided on the operation panel 52 is set in advance as a region of interest (ROI). This setting information may be stored in the imaging parameter storage 64 via the system controller 51. Thus, when the setting information is read from the imaging parameter storage 64 by the imaging parameter controller 65, the setting information is sent to the X-ray aperture controller 55 via the system controller 51. As a result, the aperture of the X-ray diaphragm 21, that is, the X-ray irradiation range is optimally adjusted in the region of interest according to the setting information. Thereby, the X-ray exposure dose can be reduced and the operation burden on the operator is also reduced.

  It should be noted that the imaging rate may also be lowered when a specific part where the flow of the contrast agent is slow is thus reached. Thus, the X-ray exposure dose can be further reduced by controlling the X-ray imaging rate in accordance with the flow rate of the contrast medium. Thereby, X-ray imaging conditions can be further optimized according to the flow of the contrast agent.

  An X-ray diagnostic apparatus according to the second embodiment of the present invention will be described with reference to FIGS.

  In the second embodiment, the routine for performing the pre-scan described above and setting the shooting parameters for the main shooting from the image obtained by the pre-scan is not automatically performed without the manual processing depending on the manual operation of the operator. It is characterized in that it can be executed automatically.

  In order to automatically set the imaging parameters, the X-ray diagnostic apparatus according to the present embodiment newly includes a skeleton processor 70 for extracting and processing a skeleton that is a contrast agent pattern, as shown in FIG. Yes. The operation panel 52 is additionally equipped with a deadman switch 71. Other hardware configurations are the same as those described in the first embodiment.

  As an example, the skeleton processor 70 is configured as a processor having a computer configuration including a CPU and various memories (not shown) for program storage, calculation, and data storage. When the skeleton processor 70 is activated, a program stored in advance in the program memory is read out to the arithmetic memory, and processing is performed according to a predetermined procedure described in the program. An outline of this processing is shown in FIG. That is, as shown in the figure, an image input unit F1 that inputs an image collected by pre-scanning, and a skeleton extraction unit F2 that performs a differentiation process for extracting an input contrast agent pattern (hereinafter referred to as a skeleton). , A storage unit F3 for storing a skeleton image, a detection unit F4 for detecting the position of an image at time tn / tn-1 to be processed for a difference, a difference extraction unit (difference circuit) F5 for performing a difference between skeletons, and an aperture opening A processing unit F6 that performs calculation and movement speed extraction is functionally provided.

  More specifically, the skeleton processor 70 performs the processes shown in FIGS. 13 and 14 in, for example, time division and in parallel during execution of the pre-scan. Among these, the process shown in FIG. 13 shows the process for determining the aperture of the X-ray diaphragm 21, and the process shown in FIG. 14 is relative to the other of the C arm 13 and the top plate 15. A process for determining a simple moving speed (in the embodiment, the C arm 13 is moved with respect to the top plate 15) is shown. Note that the skeleton processor 70 may execute only one of the processes shown in FIGS. 13 and 14.

  The skeleton processor 70 inputs image data at a certain photographing position (a plurality of sampling timings tn) collected by the currently performed pre-scan from the image recording unit 60 via the system controller 51 (step S51). . Next, the skeleton processor 70 reads the image data of the skeleton of the contrast agent processed at the previous imaging position (a plurality of sampling timings tn-1) from the built-in memory (step S52).

  Thereafter, the skeleton processor 70 sequentially performs processing for skeleton extraction, differential image generation, and determination of the aperture opening.

  First, the contrast agent skeleton at the current imaging position (a plurality of sampling timings tn) is extracted by differential processing (pattern recognition), and the image data of each pixel of the skeleton is temporarily stored in the built-in memory (step S53). ). Next, a difference for each pixel is performed between the skeletons of the contrast agent between the two imaging positions (a plurality of sampling times tn and tn-1 respectively), and a difference image is generated (step S54). FIG. 15 shows how the difference image is generated.

  Next, a difference amount (difference area) is calculated for the difference image data, and it is determined whether or not the difference amount is equal to or greater than a predetermined threshold value (step S55). When the difference amount (difference area) is equal to or larger than the threshold, the aperture amount of the X-ray diaphragm 21 corresponding to the difference amount, that is, the skeleton area as the difference result is determined with reference to the first storage table, Data indicating the throttle opening is stored in the built-in memory (step S56). On the other hand, when the difference amount (difference area) is less than the threshold value, similarly, the difference amount, that is, the opening degree of the X-ray diaphragm 21 corresponding to the skeleton area as the difference result is stored in the second storage table (first The data indicating the throttle opening is stored in the built-in memory (step S57). By performing threshold processing on the difference amount in this way, it is possible to determine the opening degree of the diaphragm in more detail and simply in accordance with the degree of the contrast agent flow rate.

  When the aperture is determined in this way, pre-scan image data at the next photographing position (a plurality of sampling timings tn + 1) is input again (step S51). Thus, the process mentioned above is repeated.

  Along with the execution of this pre-scan, a fluoroscopic image is displayed in real time during the execution. For this reason, a contrast agent skeleton is extracted at each imaging position by differential processing from data of a fluoroscopic image displayed at a sampling rate planned based on experience values and the like in advance. Among these, a difference image between the skeleton image extracted at the current photographing position (a plurality of sampling timings tn) and the skeleton image extracted at the previous photographing position (a plurality of sampling timings tn−1) is obtained. An example of the generation of the difference image is schematically shown in FIGS. From this difference image, it is possible to determine the aperture at a certain imaging position (the dotted region RG in FIG. 15C represents the optimum aperture) and to obtain the flow rate of the contrast agent.

  On the other hand, as shown in FIG. 14, the skeleton processor 70 sends the system controller 51 from the image recording unit 60 to the image data at a certain shooting position (a plurality of sampling timings tn) collected by the pre-scan currently being performed. Next, the skeleton processor 70 reads out the image data of the skeleton of the contrast agent processed at the previous imaging position (a plurality of sampling timings tn-1) from the built-in memory (step S62). ).

  Thereafter, the skeleton processor 70 sequentially performs processing for skeleton extraction, difference image generation, and determination of moving speed.

  First, the skeleton of the contrast agent is extracted by differential processing (pattern recognition) at the current imaging position (a plurality of sampling timings tn), and the image data of each pixel of the skeleton is temporarily stored in the built-in memory (step S63). ). Next, a difference for each pixel is performed between the skeletons of the contrast medium between the two imaging positions (a plurality of sampling timings tn and tn−1), and a difference image is generated (step S64). FIG. 16 shows how the difference image is generated.

  Subsequently, the movement amount of the contrast agent is calculated for the difference image data, and it is determined whether or not the movement amount is equal to or greater than a predetermined threshold (step S65). When the movement amount is equal to or larger than the threshold value, the movement speed of the C arm 13 corresponding to the large skeleton area (large throttle opening) as the difference result is determined with reference to the third storage table, and the movement speed is determined. The indicated data is stored in the built-in memory (step S66). On the other hand, when the moving amount of the contrast agent is less than the threshold, similarly, the moving speed of the C arm 13 corresponding to the skeleton area small (small aperture opening) as the difference result is the fourth storage table (third The data indicating the moving speed is stored in the built-in memory (step S67). By performing threshold processing on the movement amount in this way, the movement speed of the C-arm 13 can be determined in more detail and simply in accordance with the degree of the movement amount of the contrast agent.

  When the moving speed is determined in this way, pre-scan image data at the next photographing position (a plurality of sampling timings tn + 1) is input again (step S61). In this way, the above-described process is repeated.

  Along with the execution of this pre-scan, a fluoroscopic image is displayed in real time during the execution. For this reason, the contrast agent skeleton is sequentially extracted from the data of the image displayed at the sampling rate planned based on the experience value or the like in advance by the differentiation process. Among these, a difference image between the skeleton image extracted at the current shooting position (a plurality of sampling timings tn) and the skeleton image extracted at the previous shooting position (a plurality of sampling timings tn-1) is obtained at each shooting position. It is done. An example of the generation of the difference image is schematically shown in FIGS. 16 (a) to (c) and (d) to (f).

From these difference images, it is possible to determine the aperture (the dotted area P1 (x, y) in FIG. 16 (c)) at a certain shooting position (shooting time is typically t1), and Aperture position (dotted region P2 (x, y) in FIG. 16 (f)) can be determined (steps S65 and S66 in FIG. 14). . For this reason, the position of the aperture position from a certain photographing position of the C arm 13 (the photographing time is typically t1) to the next photographing position (the photographing time is typically t2), that is, the moving speed V ( mm / sec) is
V = (P1-P2) / (t1-t2) (2)
(Also executed in steps S65 and S66 of FIG. 14 respectively). The moving speed V of the C arm 13 is stored in the imaging parameter storage 64.

  As described above, the shooting parameter storage 64 stores the shooting parameters necessary for the main shooting, as in the case of the main shooting in the first embodiment described above. For this reason, at the time of actual imaging, these imaging parameters are read out by the imaging parameter controller 65, and the aperture of the X-ray diaphragm 21 is automatically adjusted for each imaging region (position) determined through pre-scanning. At the same time, the C arm 13 is moved following the contrast agent from the imaging at the desired imaging rate f and the desired imaging interval K to the next imaging site (position) at each imaging site.

  Therefore, according to the second embodiment, during the pre-scan, the skeleton of the contrast agent is recognized as a pattern from the fluoroscopic image obtained by the pre-scan. And stored in the imaging parameter storage unit 64. Therefore, the imaging parameter controller 65 reads information on the aperture opening degree from the imaging parameter storage unit 64 and passes the information to the X-ray aperture controller 55 via the system controller 51. Thereby, during the pre-scan, the aperture of the X-ray diaphragm 21 is adjusted almost in real time to the value designated by the X-ray diaphragm controller 55, so that the contrast medium flows away at each imaging position. The X-ray exposure of the area can be cut off, and the X-ray exposure dose to the subject can be reduced accordingly. Thus, by automatically recognizing the region where the contrast agent flows from the obtained fluoroscopic image, the flow of the contrast agent can be automatically tracked even during fluoroscopic imaging, and the opening of the X-ray diaphragm during fluoroscopic imaging. Can be adjusted almost in real time. In addition, imaging parameters such as the X-ray aperture of each imaging position and the relative movement speed between the C-arm and the top plate can be automatically set according to the flow rate and movement amount of the tracked contrast medium. The above burden can be significantly reduced.

  In general, since the blood flow in the diseased part, that is, the flow rate of the contrast agent becomes slow, the automatic tracking function for the skeleton of the contrast agent according to the second embodiment is used. The opening can be set to a particularly narrow value. For the determination of the diseased part, for example, the threshold value used for the threshold processing of the difference amount and the movement amount in FIGS. 13 and 14 may be set to an appropriate value based on an experience value or the like.

  Further, it is possible to predict the subsequent flow rate of the contrast medium using the past determination tendency and the imaging position by the threshold processing, and store this prediction information as a part of the imaging parameter information. Can do. This prediction information may be taken into control of the aperture of the X-ray diaphragm and the control of the C-arm at the time of actual imaging, and thereby the imaging parameters at the time of actual imaging can be controlled with higher accuracy. This prediction information processing can be executed by, for example, the skeleton processor 70.

  Further, according to the second embodiment, the skeleton of the contrast agent is recognized as a pattern from the fluoroscopic image obtained by the pre-scan, and the X-ray diaphragm at each imaging position for the main imaging is obtained from the pattern recognition information. Imaging parameters such as the aperture of the aperture 21, the flow rate of the contrast medium, and the moving speed of the C-arm 13 are determined and automatically stored in the imaging parameter storage 64. For this reason, unlike the first embodiment described above, the operator does not need to manually set imaging parameters for each imaging position, which is performed while displaying a fluoroscopic image after pre-scanning. Therefore, the operational support is remarkably enhanced, and the operational effort is greatly reduced.

  Further, the imaging parameters automatically set as described above are read out by the imaging parameter controller 65 during the main imaging, and are automatically transmitted to the X-ray aperture controller 55 and the holding device controller 57 via the system controller 51. Sent to. For this reason, at the time of actual photographing, the aperture and the C-arm moving speed are automatically adjusted using the photographing parameters automatically set from the pre-scan fluoroscopic image as in the first embodiment. The main shooting is executed.

  As a result, the surgeon does not have to manually move the C-arm 13 and is freed from such operation work, so that the operator can concentrate on the image diagnosis displayed with the actual photographing. For this reason, the operation effort of the operator's operation is remarkably reduced, and the operation efficiency can be improved to increase the inspection throughput.

  Furthermore, in addition to the simplification and mitigation in operation described above, the response at the time of occurrence of an abnormality by the deadman switch 71 is ensured. While the operator (operator) is pressing the deadman switch 71, this X-ray diagnostic apparatus operates normally. However, when an abnormality such as failure of the X-ray tube, C-arm, top plate, etc. occurs, the operator By canceling the pushing operation of the deadman switch 71 that has been pushed, the abnormal state can be immediately avoided.

  In each of the above-described embodiments, the X-ray detector 30 has I.D. I. 31 and the television camera 32 are coupled via the optical system 33. However, the X-ray detector applicable to the present invention is not necessarily limited to this, for example, a switching element formed on a glass substrate, It may be a flat panel detector (FPD) composed of a semiconductor array formed so as to cover the capacitor with a photoconductive film that converts radiation into charges or the like. In this case, I.I. I. The controller 58 and the television camera controller 59 are replaced with an FPD controller that controls the FPD.

  In each of the above embodiments, the top plate 15 is stationary and the C arm 13 is moved to perform X-ray imaging. However, in some cases, the C arm 13 is stationary and the top plate 15 is moved. It is also possible to perform X-ray imaging.

The perspective view which showed schematic structure of the holding | maintenance apparatus part in 1st Example of the X-ray diagnostic apparatus which concerns on this invention. The systematic diagram which showed schematic structure of the 1st Example. The top view shown in order to demonstrate the effect | action of an X-ray stop. Explanatory drawing explaining a mode that an X-ray aperture is manually set for every imaging | photography site | part in a 1st Example. Explanatory drawing shown in order to demonstrate the condition which sets the suitable imaging condition with respect to a desired site | part in a 1st Example. The figure which showed an example of the memory | storage table of the setting value (imaging parameter) determined by setting operation of imaging condition. The flowchart explaining an example of the operation | movement procedure in a 1st Example. Explanatory drawing of the profile display function of a contrast agent moving speed and C arm moving speed in the 1st example. The figure explaining other functions in the 1st example. The figure explaining further another function in the 1st example. The perspective view which showed schematic structure of the holding | maintenance apparatus part in 2nd Example of the X-ray diagnostic apparatus which concerns on this invention. The functional block diagram which shows the outline | summary of the process performed with the skeleton processor used in the 2nd Example. The flowchart which shows the outline | summary of the process for the automatic setting of the aperture opening degree of the X-ray aperture performed with a Skruton processor. The flowchart which shows the outline | summary of the process for the automatic setting of the moving speed of C arm performed with a skeleton unit. The figure explaining the automatic setting of the aperture opening degree of the X-ray diaphragm by the skeleton extraction of a contrast agent, and a difference process. The figure explaining the automatic setting of the moving speed of the C arm by the skeleton extraction of a contrast agent, and a difference process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Holding device 11 Holding device main body 12 C arm holding mechanism 13 C arm 14 Top plate holding mechanism 15 Top plate 20 X-ray tube 21 X-ray aperture 30 X-ray detector 50 Control device 51 System controller 52 Operation panel 53 High voltage generator 54 X-ray controller 55 X-ray aperture controller 56 Compensation filter controller 57 Holding device controller 58 LL controller 59 Camera controller 60 Image processor 61 Image storage device 62 Display device 63 Aperture position / size / angle calculator 64 Shooting parameter memory 65 Shooting parameter controller 70 Skeleton processor 71 Deadman switch

Claims (13)

An X-ray source for generating X-rays;
An X-ray detector for detecting the X-ray;
The X-ray source and the X-ray detector are opposed to each other, and the X-ray is so positioned that a top plate on which the subject is placed is located in a spatial space between the X-ray source and the X-ray detector. Holding means for holding the source and the X-ray detector;
While moving one of the top plate and the holding means relative to the other, the contrast agent set in the subject substantially flows with respect to the subject into which the contrast agent has been injected. Fluoroscopic imaging means for performing fluoroscopic imaging along a direction to obtain a fluoroscopic image;
Imaging parameter setting means for setting the imaging parameters necessary for the actual imaging based on the fluoroscopic image obtained by the fluoroscopic imaging means at least for each part continuous in the direction;
An irradiation control means for controlling an irradiation range of the X-ray generated from the X-ray source to the subject in a direction of a flow of a contrast medium injected into the subject based on the imaging parameter;
Based on the imaging parameters set by the imaging parameter setting means, while moving one of the top plate and the holding means relative to the other, the subject injected with the contrast agent An X-ray diagnostic apparatus comprising: a main imaging unit that performs the main imaging. The X-ray diagnostic apparatus according to claim 1,
The irradiation control means includes
An X-ray diagnostic apparatus, wherein the irradiation range in the longitudinal direction of the top plate is controlled as the direction of the contrast agent flow. The X-ray diagnostic apparatus according to claim 1 or 2,
The X-ray diagnostic apparatus is configured such that the imaging parameter setting means sets the imaging parameters according to manual information of an operator. The X-ray diagnostic apparatus according to claim 1 or 2,
The imaging parameter setting means sets, as one of the imaging parameters, a relative moving speed with respect to the other of the top plate and the holding means according to the speed at which the contrast medium flows in the subject. Means to
The irradiation range control means is an X-ray control device configured to control the irradiation range in accordance with the moving speed. The X-ray diagnostic apparatus according to claim 1 or 2,
The imaging parameter setting means is a means for setting the imaging rate of the main imaging according to the speed at which the contrast agent flows through the subject as one of the imaging parameters,
The X-ray control apparatus configured to control the irradiation range according to the imaging rate. The X-ray diagnostic apparatus according to claim 1 or 2,
A site designating unit for designating a specific site of the subject;
The irradiation range control unit controls the irradiation range to an opening suitable for imaging of the specific site when the X-ray imaging position by the main imaging unit reaches the specific site set by the site specifying unit. X-ray control apparatus having means for performing. The X-ray diagnostic apparatus according to claim 1 or 2,
The imaging parameter setting means is configured to automatically recognize a region where the projection agent flows from a fluoroscopic image obtained by the fluoroscopic imaging means and set the imaging parameters based on the recognition result. apparatus. The X-ray diagnostic apparatus according to claim 7,
The imaging parameter setting unit is configured to automatically calculate a region through which the contrast agent flows from a fluoroscopic image obtained by the fluoroscopic imaging unit by pattern recognition, and based on the calculation result calculated by the calculating unit Means for setting, as a part of the imaging parameters, the aperture of the X-ray for each position according to the region where the agent flows,
The main imaging means is an X-ray diagnostic apparatus comprising means for controlling the X-ray diaphragm according to the aperture of the X-ray. The X-ray diagnostic apparatus according to claim 7,
The imaging parameter setting unit is configured to automatically calculate a region through which the contrast agent flows from a fluoroscopic image obtained by the fluoroscopic imaging unit by pattern recognition, and based on the calculation result calculated by the calculating unit Means for setting a relative moving speed as a part of the imaging parameter with respect to the other one of the top plate and the holding means according to the flow rate of the agent,
The main imaging means is an X-ray diagnostic apparatus comprising means for controlling a relative moving speed with respect to the other of the top plate and the holding means according to the set relative moving speed. The X-ray diagnostic apparatus according to claim 7,
The imaging parameter setting unit is based on a calculation unit that automatically calculates a region through which the contrast agent flows from a fluoroscopic image obtained by the fluoroscopic imaging unit by pattern recognition, and a calculation result calculated by the calculation unit. As a part of the imaging parameters, the aperture of the X-ray and the relative movement speed with respect to the other of the top plate and the holding means for each position corresponding to the region in which the contrast agent flows. Means for setting,
The main imaging means includes a means for controlling the X-ray aperture according to the aperture of the X-ray, and the other of the top plate and the holding means according to the set relative moving speed. And an X-ray diagnostic apparatus comprising means for controlling a relative moving speed with respect to the X-ray. The X-ray diagnostic apparatus according to claim 7,
A calculation means for automatically calculating a region through which the contrast agent flows from a fluoroscopic image obtained by the fluoroscopic imaging means by pattern recognition;
Based on the calculation result calculated by the calculation means, the irradiation range of the X-ray generated from the X-ray source to the subject in parallel with the fluoroscopic imaging by the fluoroscopic imaging means is automatically and in real time. An X-ray diagnostic apparatus comprising irradiation range control means for controlling. An X-ray source that generates X-rays, an X-ray detector that detects the X-rays, and the X-ray source and the X-ray detector that face each other, and between the X-ray source and the X-ray detector An imaging method executed by an X-ray diagnostic apparatus including a holding unit that holds the X-ray source and the X-ray detector so that the top plate is positioned in a spatial space,
While one is moved relative to the other the of said top plate and said holding means, and obtaining a fluoroscopic image by performing a fluoroscopic imaging,
Setting imaging parameters necessary for the main imaging based on the fluoroscopic image obtained by the fluoroscopic imaging at least for each part continuous along the longitudinal direction of the top plate ;
A step of based on said imaging parameters, to control the irradiation morphism range of the X-ray to be generated from the previous SL X-ray source with respect to the longitudinal direction of at least the top plate,
A step of, based on the photographing imaging parameters set by the parameter setting means, while one is moved relative to the other the of said top plate and said holding means, carries out the pre-Symbol main photographing,
X-ray imaging method including: The X-ray imaging method according to claim 12,
The fluoroscopic imaging is to obtain a plurality of fluoroscopic images,
The X-ray imaging method , wherein the imaging parameters are set based on a difference image obtained from the fluoroscopic image .

Images