JP2008178714A - Local x-ray ct scanner and its image display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray CT scanner using X-ray cone beams which is small-sized, can accurately fix a target position in a comparatively short time, and can reduce exposure to X rays. <P>SOLUTION: The local X-ray CT scanner has: a preliminary photographing means to photograph a subject O under two different position conditions in which the positional relationships of three parties, an X-ray generator 1, the subject O, and an image sensor 2 differ from each other; a calculation processing means to calculation process two-dimensional position data in the subject O at the target position m fixed on the obtained two fluoroscopic images and obtain a three-dimensional position in the subject O at the target position m; a position adjustment means to adjust the positional relationships of the three parties 1, O and 2 so as to ensure that the obtained three-dimensional position is a center line of rotation; and a main photographing means to photograph a tomogram of the subject O by relatively rotating a rotating means and the subject O after an adjustment action. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an X-ray CT imaging apparatus that irradiates a part of a subject with an X-ray cone beam and obtains an arbitrary tomographic image of the part.

  When a tomographic image of a target location (affected area, etc.) of a subject is acquired using a cone beam type X-ray CT (Computed Tomography) imaging device, the imaging location is in a very limited range, that is, local imaging. In order to accurately place the target location to be imaged within the imaging area, it is necessary to position the target location in advance. Conventionally, the target location is positioned by the following method.

That is, first, CT imaging is performed, and then a plurality of fluoroscopic images for reconstruction position setting, that is, target location setting are acquired in order to prepare a plurality of fluoroscopic images for reconstruction of tomographic images (CT images). . Then, a desired one is picked up for setting the target location from the plurality of obtained fluoroscopic images, and the three-dimensional position of the target location is determined based on the fluoroscopic image thus picked up. The tomographic image of the target location can be obtained by reconstructing only the vicinity of the determined location. As what employs such an X-ray CT imaging method, for example, the one disclosed in Patent Document 1 is known.
JP 2001-292991 A JP 2002-291727 A JP 04-347143 A JP 09-276264 A JP 2002-315746 A Japanese Patent Laid-Open No. 02-237548

  In the conventional X-ray CT imaging method, a tomographic image in a range over a relatively large area is acquired so that a target location is included in the imaging area, and then a CT scan is performed over a wide range. This is a means for determining a target location from a photographed fluoroscopic image and obtaining a location to be reconstructed as a tomographic image.

  With this means, since an imaging device over a wide range and a fluoroscopic image over a wide range are acquired, the amount of X-ray exposure tends to increase and the size of the X-ray CT imaging device tends to increase. Therefore, there is room for improvement in order to reduce the size of the apparatus and shorten the time required for tomography to improve the efficiency of imaging.

  An object of the present invention is to accurately position a target location in a relatively short time while making an X-ray CT imaging device using an X-ray cone beam suitable for imaging a local location as a relatively small device, In addition, the X-ray exposure amount can be reduced.

  In order to achieve the above object, a local X-ray CT imaging apparatus according to the present invention includes an X-ray generator and a two-dimensional X-ray image sensor arranged opposite to a turning means, and the X-ray generator and the two-dimensional X-ray. A local X-ray CT imaging apparatus configured to perform imaging by irradiating an X-ray cone beam to a local part of the subject while rotating the subject located between the image sensor and the control device; Display means, and performs preliminary photographing for photographing the subject under a plurality of positional conditions in which the X-ray generator, the subject, and the two-dimensional X-ray image sensor have different positional relationships, and the display means Simultaneously displaying a plurality of fluoroscopic images obtained by the preliminary photographing, and displaying an index for designating a target location on each of the plurality of fluoroscopic images, and the control device includes the display means. In response to the operation of moving the displayed index, the index displayed on each of the plurality of fluoroscopic images is moved, and the shooting ratio of each of the plurality of fluoroscopic images is determined in the vertical direction of each of the plurality of fluoroscopic images. The positional relationship of the three members is moved so that the indicator to be displayed on each of the plurality of fluoroscopic images is moved by an amount based on the above, and thus the turning center of the turning means comes to the three-dimensional position of the subject at the subject. And adjusting the position, and after the position adjustment, main imaging is performed in which the turning means is rotated with respect to the subject to take a tomographic image of the subject.

  Another local X-ray CT imaging apparatus according to the present invention includes an X-ray generator and a two-dimensional X-ray image sensor arranged opposite to a turning means between the X-ray generator and the two-dimensional X-ray image sensor. A local X-ray CT imaging apparatus configured to perform imaging by irradiating an X-ray cone beam to a local part of the subject while turning the subject, wherein the X-ray generator, the subject, Preliminary imaging means for performing preliminary imaging for imaging the subject under a plurality of positional conditions in which the positional relationship of the three parties of the two-dimensional X-ray image sensor is different from each other, and a plurality of fluoroscopic images obtained by the preliminary imaging means are simultaneously displayed. And a display means for displaying an index for designating a target location on each of the plurality of fluoroscopic images, and an operation for moving the index displayed on the display means, With respect to the vertical direction, positioning operation means for moving an index to be displayed on each of the plurality of fluoroscopic images by an amount based on the photographing ratio of each of the plurality of fluoroscopic images, and the plurality of positions determined by the positioning operation means. Position adjusting means for adjusting the positional relationship of the three members so that the turning center of the turning means comes to the three-dimensional position of the target portion of the subject obtained from the position of each index on the fluoroscopic image of And a main photographing means for photographing a tomographic image of the subject by turning the turning means relative to the subject after the position adjustment by the position adjusting means.

  According to such a configuration, before CT imaging, a fluoroscopic image is taken with at least two types of positional relationships between the X-ray generator, the subject, and the two-dimensional X-ray image sensor, such as the front and side surfaces of the subject. Therefore, by setting the target location in the two types of fluoroscopic images, the three-dimensional position of the target location as the CT imaging target is accurately positioned. And, by the function of the position adjusting means, the turning center comes to the three-dimensional position of the obtained target location, and the turning means and the subject rotate relative to each other, and CT imaging is performed, so the target location such as the affected part is accurately positioned. In the state, a tomographic image of an intended location can be obtained.

  For example, when targeting a target location in one fluoroscopic image, if at least one target position is specified, three-dimensional data of a straight line formed by X-rays passing through the target position in the displayed fluoroscopic image is obtained. Calculated. Similarly, in another perspective image taken at different positions, straight line three-dimensional data is calculated, and the three-dimensional position of the target position is automatically calculated by calculation from the intersection of all straight lines. Can be used. As a result, the target location to be imaged first is accurately positioned using at least two fluoroscopic images, and then X-ray CT imaging is performed, so positioning can be performed quickly and accurately with less preliminary imaging. An X-ray CT imaging apparatus capable of obtaining a tomographic image of an intended location efficiently in a short time can be provided.

  In the local X-ray CT imaging apparatus having such a configuration, the ratio of the interval between the subject and the two-dimensional X-ray image sensor to the interval between the X-ray generator and the two-dimensional X-ray image sensor can be changed. A ratio changing unit may be provided. At this time, a chair on which the subject as the subject sits may be provided, and the ratio changing unit may change the ratio by moving the chair.

  According to this configuration, the subject for the distance between the X-ray generator and the two-dimensional X-ray image sensor is greater when the fluoroscopic image for positioning is taken than when the tomographic image is taken by X-ray CT. And the two-dimensional X-ray image sensor are photographed with a small ratio of the distance between the two-dimensional X-ray image sensor, that is, the image is reduced to a small size. Therefore, in order to obtain one fluoroscopic image in which a target location exists, it is not necessary to take a plurality of fluoroscopic images by changing the position condition, and only one fluoroscopic image is required. Thus, it is possible to efficiently obtain a fluoroscopic image having a target location.

  In any one of the above-mentioned local X-ray CT imaging apparatuses, the two-dimensional X-ray image sensor is orthogonal to the X-ray cone beam irradiated from the X-ray generator for imaging the fluoroscopic image by the preliminary imaging. It is good also as what has a scanning imaging | photography means performed while making it slide in the direction to do.

  According to such a configuration, the X-ray generator and the two-dimensional X-ray image sensor are arranged in a direction orthogonal to the irradiated X-ray cone beam, preferably in the horizontal direction or the horizontal direction. Since the slide movement is performed in the vertical direction, the fluoroscopic image area can be substantially expanded in a state where the distance from the X-ray generator hardly changes, and the entire area for finding the target location of the affected part in the subject is enlarged. be able to. Therefore, it is possible to restrict the shooting of useless fluoroscopic images, and it is possible to efficiently acquire a fluoroscopic image having a target location.

  Further, in any one of the above-mentioned local X-ray CT imaging apparatuses, the plurality of fluoroscopic images are angles formed by the X-ray generator and the two-dimensional X-ray image sensor with respect to the subject at the time of the preliminary imaging. Are first and second fluoroscopic images photographed under two different position conditions, and a plane in which the swivel arm pivots in the vertical direction in which the index is moved in each of the first and second fluoroscopic images. The first direction is a direction perpendicular to the first direction.

  And when comprised in this way, the said index | index is a cursor displayed on the said fluoroscopic image, In response to the movement operation of the said index | index, the said cursor is moved in the said 1st fluoroscopic image, and said 1st direction And setting a position in a third direction different from the first and second directions by moving the cursor in the second fluoroscopic image. The target position may be specified by setting the position by moving the cursor between the first and second fluoroscopic images.

  By configuring in this way, a target location is determined while displaying a fluoroscopic image on a display means such as a liquid crystal screen, and if a vertical or horizontal cursor is specified in the fluoroscopic image displayed on one side, the target location is determined. The two-dimensional position is determined, and the three-dimensional position is determined by specifying a horizontal or vertical cursor different from the previous one in the other fluoroscopic image. Thus, specifying a target location using a known cursor such as a vertical or horizontal cross cursor (pointing) can be easily performed using a popular device such as a personal computer, so that it is convenient and convenient.

  In any one of the local X-ray CT imaging apparatuses described above, the plurality of fluoroscopic images for determining the target location and the tomographic images of the target location determined from the fluoroscopic images are associated and stored. When the target portion of the subject in the fluoroscopic image selected from the image storage means and the fluoroscopic image stored in the image storage means and displayed on the display means is specified, the specified target location A function of displaying the tomographic image on the display means, and / or in a state where the tomographic image selected from the tomographic images stored in the image storage means is displayed on the display means Image calling means having a function of displaying the fluoroscopic image used for obtaining the position of the displayed tomographic image may be provided.

  According to such a configuration, a plurality of fluoroscopic images prior to CT imaging and a tomographic image obtained by CT imaging positioned thereby are linked, that is, associated with each other, stored and linked. When one of the fluoroscopic image and the tomographic image is designated, the image of the other party is automatically retrieved and called, so that it is very convenient that related images can be quickly retrieved. For example, when a tomographic image of the inner ear is displayed on the display means, two or more fluoroscopic images used for positioning are searched for and displayed, or two fluoroscopic images are displayed. For example, a tomographic image of a portion positioned by the fluoroscopic images is searched for and displayed by a click operation when selected and displayed.

  Furthermore, as the three-dimensional position is obtained, the photographing area display control means for displaying the photographing area of the tomographic image related to the obtained three-dimensional position on the fluoroscopic image displayed on the display means is provided. Also good.

  As a result, when the three-dimensional position of the target location is obtained from the plurality of fluoroscopic images, the tomographic image capturing region by CT imaging related to the target location is simultaneously displayed. Therefore, the imaging region of the tomographic image can be grasped at the time when the target location is determined without waiting until the image reconstructed after CT imaging, that is, the tomographic image is viewed, which is very convenient. For example, if the tomographic image area is large, the CT imaging ratio can be reduced, or if the tomographic image area is small, the CT imaging ratio can be increased in advance. There is an advantage that it is possible to prevent the problem from being corrected.

  The image display method in the local X-ray CT imaging apparatus of the present invention includes an X-ray generator and a two-dimensional X-ray image sensor arranged opposite to a turning means, and the X-ray generator and the two-dimensional X-ray image sensor. An image display method in a local X-ray CT imaging apparatus that images a tomographic image of the subject by irradiating a local site of the subject with an X-ray cone beam while rotating the subject positioned between The display means of the local X-ray CT imaging apparatus has a plurality of objects photographed under a plurality of positional conditions in which the positional relationship among the X-ray generator, the object, and the two-dimensional X-ray image sensor is different from each other. A fluoroscopic image is displayed at the same time, and an indicator for designating a target location for determining a turning center of the turning means when taking the tomographic image is displayed on each of the plurality of fluoroscopic images. And a movement amount of the index when the index movement operation is received, and the movement amount of the index to be displayed on the plurality of fluoroscopic images is calculated according to the respective photographing ratios between the plurality of fluoroscopic images. And moving the index in the vertical direction of each of the plurality of fluoroscopic images.

  According to the present invention, first, a target location to be imaged is accurately positioned using at least two fluoroscopic images, and then X-ray CT imaging is performed. The tomographic image of the intended location can be obtained efficiently in a short time. At this time, it is possible to simplify the setting operation of the turning center to the three-dimensional position in the subject by moving the index displayed by the plurality of fluoroscopic images according to the imaging ratio of the fluoroscopic images by the positioning operation means. It is possible to set more quickly.

  In addition, when photographing a fluoroscopic image for positioning, the subject and the two-dimensional X-ray with respect to the distance between the X-ray generator and the two-dimensional X-ray image sensor are better than when photographing a tomographic image by X-ray CT. By setting the ratio of the distance to the line image sensor to be large, that is, by taking an image with a reduced image, it is possible to enlarge the entire area where the target position such as the affected part of the subject is searched.

  Furthermore, since it is possible to restrict the shooting of useless fluoroscopic images, it is possible to efficiently acquire a fluoroscopic image having a target position. Also, by specifying the target position using the vertical and horizontal cross cursors (pointing), it can be easily performed using a popular device such as a personal computer, so that it is easy to use and has a convenient configuration.

  Further, a plurality of fluoroscopic images prior to CT imaging and a tomographic image obtained by CT imaging positioned thereby are linked and stored, and one of the linked fluoroscopic images and tomographic images is designated. Since the image of the other party is automatically searched and called, the related images can be searched quickly.

  Furthermore, when the three-dimensional position of the target position is obtained from a plurality of fluoroscopic images, the tomographic image capturing area by CT imaging related to the target position is displayed at the same time, so that the CT image can be reproduced after CT imaging. The imaging region of the tomographic image can be grasped when the target position is determined without waiting until the constructed image, that is, the tomographic image is viewed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 is a front view and a side view showing an external appearance of the X-ray CT imaging apparatus of the present invention, FIG. 2 is a basic configuration diagram, and FIG. 3 is a conceptual diagram showing the principle of a positioning method. Note that d in FIG. 3 and FIG. 7 is a turning movement locus of the turning means 3.

  As shown in FIGS. 1 and 2, the X-ray CT imaging apparatus 20 is configured with a main frame 10 that is a portal-type very rigid structure as a whole support. The main frame 10 has an arm 10a for rotatably supporting a turning means 3 suspended from the X-ray generator 1 and the two-dimensional X-ray image sensor 2, and a base end portion of the arm 10a is fixed. A pair of horizontal beams 10b that are held, a pair of vertical beams 10c that support the horizontal beams 10b, and a pair of vertical beams 10c are fixedly mounted, and are composed of a base 10d that forms the basis of the entire apparatus 20. Has been.

  Each of the members constituting the main frame 10 is made of a steel material having high rigidity, and is appropriately provided with braces or corner reinforcing members so as to be resistant to deformation. The turning center 3a is not changed. As described above, the main frame 10 has a structure that does not cause the swiveling shake of the swiveling means 3, and is particularly suitable as an X-ray CT imaging apparatus that is required to have no swiveling shake.

  The operation panel 10e is provided on the surface of one vertical beam 10c of the main frame 10 at a position where the operator can easily operate in a standing position. The chair 4b of the subject holding means 4 is placed on the subject position moving means 5 described later with reference to FIG. 3, and the chair 4b is moved in the X, Y, and Z directions, that is, in the front and rear, right and left, up and down directions. Moreover, the head 4 of the subject O can be tilted and held by tilting the back plate 4a of the chair 4b.

  Next, the basic configuration of the X-ray CT imaging apparatus will be described. As shown in FIG. 2, the X-ray CT imaging apparatus 20 includes a control device 7 by a personal computer main body that is the basis of all operations, and also includes an X-ray imaging means A, an X-ray beam adjustment means B, a turning means drive control means. C, calculation processing means 6, display monitor such as a liquid crystal screen (an example of display means) E, subject holding means 4 for fixing and holding subject O, subject position moving means 5 for moving subject holding means 4, main frame 10, operation Unit 11, an operation panel 10e, and the like. 8 is a keyboard, and 9 is a mouse.

  The X-ray imaging means A has a turning means 3, and the turning means 3 suspends the X-ray generator 1 and the two-dimensional X-ray image sensor 2 from each other. The swivel means 3 may be an arm-shaped swivel arm as shown in the figure, or a known gantry that images a patient horizontally, and the X-ray generator 1 and the two-dimensional X-ray image sensor 2 are arranged facing each other. Any shape that can turn is acceptable. The X-ray beam adjusting unit B includes an X-ray beam width limiting unit B1, an X-ray beam controller B2, and an emission control slit B3. The X-ray beam emitted from the X-ray tube is limited to the X-ray beam width. The X-ray cone beam 1a having a desired beam width can be radiated by adjusting by means B1. The X-ray beam adjusting means B may be provided in the X-ray generator 1. The X-ray cone beam 1a described here may have a beam shape forming a cone or a beam shape forming a pyramid.

  When obtaining a later-described fluoroscopic image by the X-ray beam controller B2, an X-ray beam having a large cross section is irradiated, and when taking a tomographic image as X-ray CT imaging described later, an X-ray beam having a small cross section is irradiated. By doing so, a wide range of fluoroscopic images are obtained for fluoroscopic images with a relatively small amount of X-ray irradiation, and tomographic images with a relatively large amount of X-ray irradiation for continuous X-ray irradiation. The X-ray emission can be performed only in the region of interest, the diagnostic efficiency is good, and the X-ray irradiation amount can be reduced. When a wide range of sensors such as an X-ray MOS sensor is used, the above efficiency is even higher.

  One two-dimensional X-ray image sensor 2 converts X-rays that hit a scintillator layer provided on the surface of X-ray II into visible light, converts the visible light into electrons by a photoelectric converter, and multiplies the electrons. This electron is converted into visible light by a phosphor and photographed with a CCD (solid-state imaging device) camera arranged two-dimensionally through a lens. In addition, the two-dimensional X-ray image sensor 2 includes an X-ray TFT (Thin Film Transistor) sensor, an X-ray MOS (Metal Oxide Semiconductor) sensor, an X-ray II (Image Intensifier) camera, an X-ray amorphous selenium sensor, It is also possible to use an X-ray CCD (Charge Coupled Device) sensor, an X-ray CCD sensor with an amplifier (XICCD), or the like.

  The subject holding means 4 includes a chair 4b that holds the subject (patient) O in a sitting position, and a head fixing means 4a provided on the back of the chair 4b. The subject position moving means 5 moves the subject holding means 4 in the X direction which is the left-right direction from the front of FIG. 1A, and the subject holding means 4 from the front of FIG. A Y-axis control motor 52 that moves in the Y direction, which is the front-rear direction, and a Z-axis control motor 53 that is a vertical movement means that moves the subject holding means 4 in the vertical direction from the front of FIG. Yes.

  The X-axis, Y-axis, and Z-axis linear movement tables (not shown) driven by these motors 51 to 53 are each composed of a well-known cross roller guide or a combination of ordinary bearings and guides. It can be linearly moved. In addition, the movement of these X-axis, Y-axis, and Z-axis linear movement tables by the motors 51 to 53 can be applied with a rack and pinion method, a ball screw method, a method using a normal screw shaft, or the like. What can be positioned is desirable.

  In this way, the subject O is seated on the chair 4b, the head fixing means 4a holds the head of the subject O fixed, and the subject position moving means 5 is used to bring the inside of the subject O into the turning center 3a of the turning means 3. It can be adjusted to the center of the local site. When a gantry is used for the swivel means 3, the subject is usually lying on the bed, so the subject holding means 4 is also shaped like a bed, and the X direction, the front-rear direction, which is the left-right direction when viewed from the front side of the patient It is possible to move three-dimensionally in the Y direction and the Z direction which is the vertical direction. That is, as in the embodiment of the present application, the turning means may be swung on the horizontal plane around the person's imaging target part by sitting or standing up, but the patient is lying on the patient's side. The turning means may turn on a vertical plane around the imaging target region.

  The above is an example in which the position of the subject relative to the turning means is adjusted by moving only the subject holding means 4 while the turning means 3 is fixed. On the other hand, instead of moving the subject holding means 4 by the subject position moving means 5. In addition, the subject holding means 4 is fixed and does not move in any of the X, Y, and Z directions, and the turning means 3 side is moved using an XY table 31 and a lift control motor 32 described later to turn the turning means. It is also possible to match the three turning centers 3a with the center of the local part inside the subject O. Of course, both the subject holding means 4 and the turning means 3 may be moved in combination to adjust the position.

  The swiveling means 3 includes an XY table 31 that can move in directions orthogonal to each other on a horizontal plane, and an X-axis control motor 31a that moves the XY table 31 in the X direction that is the left-right direction from the front of FIG. And a Y-axis control motor 31b that moves in the Y direction perpendicular to the X direction, and a lift control that moves the turning means 3 in the vertical direction from the front of FIG. 1A perpendicular to the XY table 31 in the vertical direction. A motor 32 and a rotation control motor 33 for turning the turning means 3 are provided, and the turning center 3a of the turning means 3 is positioned in the XY direction by controlling the X-axis control motor 31a and the Y-axis control motor 31b. The swiveling means 3 can be moved up and down by driving the lift control motor 32, and the rotation control motor 33 can be driven at a constant speed during shooting. 3 is to be pivoted about the object O a. Thus, the elevation control motor 32 constitutes the arm vertical position adjustment means of the turning means 3.

  Further, the turning center 3a of the turning means 3, that is, the turning axis is provided vertically, the turning means 3 rotates horizontally, and the X-ray cone beam 1a is locally irradiated horizontally, so that the apparatus occupies a small floor area. It can be configured as a vertical type. The rotation control motor 33 constitutes a turning drive means for the turning means 3, and uses a motor that can freely control the rotation speed and rotation position thereof, such as a servo motor. Is installed on the pivot center 3a of the shaft directly connected to the shaft.

  Therefore, the swiveling means 3 can be rotated at a constant speed or a variable speed, and the rotational position can be known along the time axis. It is convenient for taking out a transmission image, and local irradiation X-ray CT imaging can be effectively carried out with no center shake.

  A hollow portion 3 b is provided at the turning center 3 a of the turning means 3. In order to provide such a hollow portion 3b, it is necessary to provide a hollow hole in all the related parts on the turning center 3a. For example, the rotation control motor 33 uses a servo that uses a hollow shaft. A motor can be used. The hollow portion 3b is provided with a connection line between the X-ray generator 1 and the two-dimensional X-ray imaging means 2 suspended from the turning means 3 and the operation part 11 provided on the main frame 10 side. belongs to.

  When electrical wiring is connected to the rotating portion, the arrangement method of the connecting wire becomes a problem. However, if the connecting wire is arranged through the turning center 3a of the turning means 3 as described above, the influence of twisting due to rotation or the like is exerted. Can be minimized, and a favorable effect can be obtained from the aesthetics of the wiring. In this embodiment, the turning means drive control means C is configured by combining the position adjusting means 31 composed of an XY table, the motor 32 after lift control, and the rotation control motor 33, but is not limited to such a configuration. . In the simplest structure, the center 3a of the turning means 3 may be set at an arbitrary position by operating a handwheel handle.

  In this apparatus 20, in order to align the turning center 3a, that is, to set the X-ray imaging position, the subject position moving means 5 for moving the subject side, and the XY table 31 for moving the turning means 3 on the irradiation side, Although both the lift control motors 32 are provided, only one of them may be provided. In the case of local irradiation X-ray CT imaging, since it is important that there is no blurring of the turning center 3a, it is desirable that the turning means 3 side is only turned during CT imaging, and the turning center 3a is fixed.

  The arithmetic processing means 6 includes an arithmetic processor that operates at high speed for image processing analysis, and performs a predetermined arithmetic processing after pre-processing the X-ray transmission image generated on the two-dimensional X-ray imaging means 2. By calculating the three-dimensional X-ray absorption coefficient data inside the object through which X-rays are transmitted, and performing calculations such as projection of this data on the projection surface, the projection image is projected onto the external display means three-dimensionally. Alternatively, an X-ray image is displayed and stored as image information in a necessary storage medium.

  Next, a method for positioning a target location for tomography will be described. The X-ray CT imaging apparatus 20 according to the present invention is a preliminary imaging means D that images the subject O under a plurality of positional conditions in which the positional relationship among the X-ray generator 1, the subject O, and the two-dimensional X-ray image sensor 2 is different. And the two-dimensional position data of the subject O at the target location artificially determined on the plurality of fluoroscopic images obtained by the preliminary photographing means D, and calculating the three-dimensional position of the subject O at the target location. The calculation processing means 6 to be obtained, the position adjustment means F for adjusting the positional relationship between the three parties 1, O, 2 so that the turning center 3a comes to the three-dimensional position obtained by the calculation processing means 6, and the position adjustment. After the adjustment operation by means F, a main photographing means G for taking a tomographic image of the subject O by relatively turning the turning means 3 and the subject O is provided.

  Here, the target location is a location that becomes a target in order to designate a location to be imaged, and the target location e described in this specification can be designated within a certain range. It can also be specified. In short, in this specification, it may be a guideline for designating an object to be tomographed. When a target location is used as a target at a specific one point, that one point is particularly referred to as a target position in this specification. The target position m described in this specification has this meaning. The target position m is preferably specified in the imaging area, and more preferably specified in the center of the imaging area.

  Now, as shown in FIG. 3, the target location is roughly positioned by controlling the posture of the chair 4b. Specifically, the head of the subject O is placed on the X-ray generator 1 and the two-dimensional X-ray. It is located between the line image sensor 2. Then, a state in which these three parties 1, O, 2 are in a certain positional relationship, for example, a first positional relationship P1 in which the X-ray cone beam passes from the front of the head to the back is set, and imaging is performed in that state. To obtain a first fluoroscopic image (hereinafter referred to as a scout image) sc1.

  Next, the swiveling means 3 is swiveled by an appropriate angle (for example, 90 degrees) to set the second positional relationship P2 such that the X-ray cone beam passes from the left side surface of the head to the right side surface. To obtain a second scout image sc2. These scout images sc1 and sc2 are stored in the image storage means K as needed. These two shootings are performed by the function of the preliminary shooting means D by operating the operation panel 10e.

  The captured scout images sc1 and sc2 are displayed side by side on the display monitor E as shown in FIG. Therefore, as shown in FIG. 4A, for example, in the first scout image sc1 displayed on the left side, the mouse 9 is operated to move the cursor to the approximate center of the target location e that appears to be the affected area, When the button is clicked, a horizontal position h that is a vertical position and a vertical position t that is a horizontal position are designated. At this time, the vertical position t ′ on the second scout image sc2 is displayed at the center as the initial position, and the horizontal position h ′ is displayed at a position corresponding to the horizontal position h on the first scout image sc1 obtained by calculation. The

  Next, as shown in FIG. 4A, the cursor is moved to the second scout image sc2, and the cursor is moved to the approximate center of the target location e in the second scout image sc2, and the position, that is, the target position m. Is clicked, the vertical positions t and t ′, which are the positions in the left and right direction, are designated, and the three-dimensional position of the target position m is determined by this, and this series of positioning operations is performed by the positioning operation means J. Done by function. Since this vertical position is also displayed simultaneously in the first scout image sc1 arranged on the left and right, if both the vertical and horizontal are clicked, the three-dimensional position of the target position m is found in any of the scout images sc1 and sc2. A fixed display appears.

  As described above, when the designation of the three-dimensional position of the target position m is completed, the data is calculated by the arithmetic processing means 6, and the imaging center position by the X-ray imaging means A, that is, the turning center 3a of the turning arm 3 is set as the target. The position adjustment control means F functions so as to be at the position m, and in order to adjust the position of the chair 4b, the X-axis control motor 51, the Y-axis control motor 52, and the Z-axis control motor 53 are controlled. The position is adjusted and set. Alternatively, the X-axis control motor 31a, the Y-axis control motor 31b, and the elevation control motor 32 are appropriately driven and controlled without adjusting the position control motor of the chair 4b, so that the position of the turning means 3 is adjusted and set. Also good.

  When the positioning of the target position is completed, a display such as “target position setting complete” appears on the display monitor E, and after confirming this, the operation panel 10e is operated to activate the main imaging means G to perform CT imaging. An image captured by the CT imaging is reconstructed using the arithmetic processing unit 6 and the like when the imaging is completed, and a reconstructed image by the CT imaging, that is, a tomographic image, is a target position that was performed prior to the imaging. It is stored in the image storage means K in a state of being linked (associated) with the two scout images sc1 and sc2 for positioning m.

  As described above, the preliminary imaging means D includes at least the X-ray generator 1, the subject holding means 4, the two-dimensional X-ray image sensor 2, and the turning means 3. In addition, the calculation processing means 6 and the position adjustment means F are provided.

  As described above, by performing preliminary imaging using a scout image, CT imaging regarding an intended location can be performed quickly and without waste while accurately positioning the target location, and many These scout images and CT images are stored in the control device 7. Therefore, the computer operation using the keyboard 8 and the mouse 9 is performed, for example, the CT image taken on what day of the month is called, and when there are a plurality of called CT images, one of them is selected. When selected by clicking, a character “Scout!” Is displayed at a location such as the lower right corner of the screen of the display monitor E on which the selected CT image is displayed.

  Then, by operating the mouse 9 and moving the cursor to the “Scout!” Display part and clicking, the two (or more) scouts used for positioning the displayed CT image. For example, the images sc1 and sc2 are simultaneously displayed in the upper left corner of the screen of the display monitor E. In this state, when the scout image displayed in a small size is clicked, the scout images sc1 and sc2 are displayed in full on the display monitor E with the upper body arranged horizontally, and the CT image is displayed in a small size in the upper left corner. It is convenient if the master-slave relationship of the size is reversed and displayed. The operations of these examples are controlled by the image storage means K and the image calling means L provided in the control device 7.

  Next, the ratio setting unit 12 will be described. As shown in FIG. 2, ratio changing means H that can change the relative ratio of the distance between the subject O and the two-dimensional X-ray image sensor 2 with respect to the distance between the X-ray generator 1 and the two-dimensional X-ray image sensor 2. In addition to being provided in the control device 7, a ratio setting unit 12 is provided in the operation unit 11 for setting the relative ratio to be smaller when capturing a scout image than when capturing a tomographic image.

  That is, when setting a target location on a scout image, it is desirable from the viewpoint of workability to be able to select from as large an imaging region as possible, but local radiography X-ray CT suitable for dentistry, otolaryngology, etc. In the case of the photographing apparatus 20, the photographing area is originally narrow. Thus, in scout image capturing for searching for and determining a target location, it is best to capture a wide area of the subject O. However, in this state, only a scout image in a relatively narrow area can be captured.

  Therefore, as shown in FIG. 6, the scout image detected by the two-dimensional X-ray image sensor 2 is reduced by moving the position of the chair 4b from the normal position to the two-dimensional X-ray image sensor 2 side. The shooting area is enlarged. The ratio changing means H can be moved not only by moving the chair 4b but also by moving the turning means 3. Assuming that the size of the target location e of the subject O in the scout image is w1, the size of the target location e in the scout image when the chair 4b is shifted backward is w2, as indicated by a virtual line in FIG. Become.

  At this time, since w1> w2, the ratio of the target location e to the overall size of the scout image is smaller in the state where the chair 4b is shifted to the rear, and thus the photographing area as the scout image is enlarged. It will be. The magnification of the photographing area is w1 / w2. In the above, for easy understanding, first, the target location e of the subject O is at the position when the tomographic image is taken, and the position of the chair 4b is moved from that position to move the two-dimensional X-ray image sensor from the normal position. Although the example of approaching to the second side has been described, control may be performed so that the target location e of the subject O comes to the position approached to the two-dimensional X-ray image sensor 2 side from the beginning of scout image capturing.

  Next, the scanning photographing means I will be described. The purpose of the scanning photographing means I is to enlarge the scout image, like the ratio setting means 12 described above. In other words, the scanning photographing means I has a function of photographing the fluoroscopic image in the preliminary photographing means D while sliding the two-dimensional X-ray image sensor 2 with respect to the X-ray generator 1 in the horizontal or vertical direction. is there. Specifically, as shown in FIG. 7, the two-dimensional X-ray image sensor 2 is laterally slid by appropriate moving means when a scout image is captured. As a result, the horizontal width of the image is expanded from Q1 when stationary to Q2, and the expansion ratio is Q2 / Q1. In FIG. 7, the subject O is omitted for simplicity.

  The features of the X-ray CT imaging apparatus according to the present invention will be described below. In the position adjustment of the X-ray generator 1, the subject O, and the two-dimensional X-ray image sensor 2 when acquiring the two scout images sc1 and sc2, there is an angle that is easy to see in the scout image depending on the imaging region. As it seems, it would be wise to preset the shooting direction in advance (for example, when shooting the ossicles, a degree and b degree are determined in advance). Further, if there is an angle at which it is easy to see in the scout image based on the knowledge of the surgeon, the surgeon may set it before taking the scout image. If neither of these is the case, if the recommended shooting angle is determined, it is possible to proceed quickly without losing the angle setting.

  In the conventional X-ray CT imaging apparatus, there is a method of positioning with the front, rear, left and right optical markers indicating the height of the rotation axis center and the center of the two-dimensional X-ray image sensor in order to determine the imaging region. In this method, the optical marker appears on the surface of the subject, and the photographing area inside the subject must be estimated from the position, and it is difficult to accurately position the subject.

  In the present invention, before CT imaging, scout images are taken from two directions, these images are displayed on a display (display monitor E), and a portion of the CT image to be taken is shown on the images using a mouse. The target location m is pointed (clicked) at the location. Since the point on the space where CT imaging is desired exists on the straight line connecting the pointing position and the focal point of the X-ray cone beam, if there are at least two such lines, the point on the space where CT imaging is desired is determined. it can. By moving the turning means 3 or the chair 4b so that the determined point becomes the turning center of CT imaging, CT imaging can be performed at a desired position.

  FIG. 15A is a conceptual diagram showing the display of a fluoroscopic image according to the present invention, and FIG. 15B is a conceptual diagram showing a tomographic image of a target location imaged based on the target location defined on the fluoroscopic image. It is.

  That is, as shown in FIG. 15A, if the cursor is moved in order to designate a target location m displayed in a plurality of fluoroscopic images photographed by the preliminary photographing by the preliminary photographing means D described above, Corresponding to the position, the turning means turns at the position determined by the above-described procedure, and the tomography which is X-ray CT imaging is performed. As shown in FIG. It is displayed as a tomographic image cut out in each of the Y and Z directions. A method for extracting and displaying a tomographic image in each of the X, Y, and Z directions is disclosed in Japanese Patent Application Laid-Open No. 2002-11000 filed by the applicant of the present application, and can be employed as an example of the present application. is there.

  Further, in the above, as shown in FIG. 17A, an example in which the image cutout direction is cut out at a predetermined interval in at least one of the X, Y, and Z axis directions has been shown. As shown in b), a method of cutting out a plurality of images by image processing so as to determine an axis CTR within the imaging region of interest and rotate around the axis CTR is also conceivable.

  Since the plurality of fluoroscopic images and the tomographic image obtained based on the fluoroscopic images are stored in the image storage means K, the image calling means L can be arbitrarily called. Further, since the plurality of fluoroscopic images and the tomographic images obtained based on the fluoroscopic images can be stored in the image storage means K in association with each other, either the fluoroscopic image or the tomographic image is stored. In the state of calling, the other can be called by the image calling means.

  At that time, the fluoroscopic image and the tomographic image may be displayed on the same screen. Alternatively, a plurality of one of the fluoroscopic image and the tomographic image may be called up and displayed side by side as so-called thumbnails, and the corresponding other image may be displayed by selecting one of them. FIG. 16 is a diagram for conceptual understanding from identification of a region of interest for X-ray CT imaging based on a fluoroscopic image to imaging of a tomographic image as X-ray CT imaging, as described above. It is an image display. Since the names and actions of the respective parts are duplicated, they are omitted and only the reference numerals are shown in FIG.

As a reference, an actual calculation method required for positioning in the cone beam X-ray CT imaging apparatus will be described.
1. The two-way scout basically determines a point in the space by designating a point on a projected image taken from two directions.
2. Determining a point on a scout image is equivalent to determining a straight line in space. This straight line connects a point on the image sensor and the focal point.
3. There is a possibility that the position of the chair may be translated from the reference point on the (X, Y) plane during scout shooting with the MCT apparatus. The Z coordinate of the focus of the X-ray tube and the distance between the focus and the image sensor do not change.
4). When the chair moves in parallel, the positional relationship between the imaging system (focus, turning center, screen) and the subject changes relatively. This is considered to be equivalent to fixing the chair and translating the imaging system in the direction opposite to the chair movement. This is because 2. It is equivalent to translating a straight line in the space.
5. Since there are two scout images, there are two straight lines in space. These two straight lines need to intersect. Therefore, the two straight lines are not independent. On each scout image, the user can arbitrarily specify the X coordinate, but if one of the Z coordinates is specified, the other is automatically determined.

  For reference, FIGS. 9 to 13 are flowcharts showing a work procedure (main routine: from step # 1 to step # 30) using a series of CT imaging apparatuses from imaging for scout images to imaging of tomographic images. The figure is shown. 9 to 12 proceed as a series of operations, and thereafter, as shown in FIG. 13, a tomographic image that calls a tomographic image (CT image) from a fluoroscopic image (scout image) by the function of the image calling means L. Select a subroutine for calling an image (from steps # 31 to # 35) or a subroutine for calling a perspective image (from steps # 36 to # 41) for calling a perspective image from a tomographic image as shown in FIG. It is possible to continue.

  Here, supplementary explanation in each flow chart will be given. The “other mode” in step # 1 is, for example, CT imaging. The UID in steps # 15, 23, 30, 34, and 40 is “Unique ID”, which is a unique ID number assigned to each image. The scout image sc1 of step # 2 is the first fluoroscopic image, and the scout image sc2 of step # 7 is the second fluoroscopic image. The scout images sc1 and sc2 have the same meaning in all subsequent steps.

  The tomographic image calling subroutine (see FIG. 13) and the fluoroscopic image calling subroutine (see FIG. 14) are possible routines after steps # 1 to # 30 have been completed. There may be a plurality of target positions m in step # 32. In other words, a plurality of target positions m may be designated on the same pair of fluoroscopic images. In the flowchart, the turning means 3 is described as a turning arm.

  Here, a supplementary description will be given of routine V (# 24-1 to # 24-7) that defines step # 24 in the main routine. First, the two-dimensional position on the monitor of the target position m of the scout image sc1 displayed on the monitor is calculated as two-dimensional position information by pixels (step # 24-1). Then, the three-dimensional position information of the target position m on the detection surface of the two-dimensional X-ray sensor corresponding to the value of the two-dimensional position information by the pixel and the turning arm angle, that is, the target position m on the detection surface of the two-dimensional X-ray sensor. The three-dimensional position information in the actual three-dimensional space is calculated (step # 24-2). From the calculated three-dimensional position information, swivel arm angle, and X-ray generator position information, three-dimensional data of the straight line l100 formed by the X-ray passing through the target position m from the X-ray generator is calculated (step # 24-3). ).

  Next, the two-dimensional position on the monitor of the target position m of the second scout image sc2 displayed on the monitor is calculated as the two-dimensional position information by the pixel (step # 24-4), and the two-dimensional position information by the pixel is calculated. The three-dimensional position information of the target position m on the detection surface of the two-dimensional X-ray sensor corresponding to the value and the swivel arm angle, that is, the actual three-dimensional position of the detection position of the target position m on the detection surface of the two-dimensional X-ray sensor Three-dimensional position information in the space is calculated (step # 24-5). From the calculated three-dimensional position information, swivel arm angle, and X-ray generator position information, three-dimensional data of a straight line l200 formed by the X-ray passing through the target position m from the X-ray generator is calculated (step # 24-6). ). Then, the three-dimensional position (target position m) of the intersection of the straight line l100 and the straight line l200 is calculated (step # 24-7).

[Another embodiment]
<1> Imaging region display control for displaying a tomographic image capturing region relating to the determined three-dimensional position on a fluoroscopic image displayed on the display monitor E as the three-dimensional position is determined by the preliminary imaging means D Means M may be provided. That is, as shown in FIG. 8, in the second scout image sc2, the three-dimensional position of the target position m is determined by the second pointing (clicking) of the target position. An imaging region R (a square portion indicated by a broken line in FIG. 8) of a tomographic image obtained by X-ray CT imaging based on the obtained three-dimensional position data is displayed. For example, it is more convenient if the photographic area R has dimensions such as 400 mm in width and 300 mm in length on the screen at the same time.

<2> The procedure for positioning the target position m with the cross cursor when the scout images sc1 and sc2 having different shooting ratios are used is as shown in FIG. That is, when the image of the first scout image sc1 is small and the image of the second scout image sc2 is large, as shown in FIG. 5A, the cursor is placed from the dotted line to the solid line to determine the horizontal position h. When the distance h1 is moved on the screen, the cursor moves the distance h2 on the second scout image on the right side. That is, the movement of the cursor is enlarged in the second scout image on the right side.

  Next, as shown in FIG. 5 (b), the cursor is moved to the second scout image sc2, and further, the cursor is moved to the approximate center of the target location e in the second scout image sc2, and clicked at that position. In this case, the vertical positions t and t ′ which are the positions in the left and right direction are designated, and thereby the three-dimensional position of the target position m is determined. This series of positioning operations is performed by the function of the positioning operation means J. Is called. That is, even if the enlargement ratio is different, the ratio of the movement of the cursor is changed accordingly, so that the positioning operation of the target position m can be performed without any trouble.

  In the above-described embodiment, the shape of the cursor indicating the vertical position and the horizontal position at the same time is listed. However, for example, the vertical position is designated with the cursor of only the vertical position on the first scout image, and the second scout is specified. The horizontal cursor on the image also appears in both the first scout image and the second scout image, and the position is adjusted between the first scout image and the second scout image, or on both scout images. It is possible to make appropriate changes such as simply indicating an arrow pointer.

  FIG. 18 shows an example of the cursor. (A) is an example in which a circular cursor is used to designate a target location e or target position m. It goes without saying that not only circles but also various figures can be used. (B) is an example in which a cross cursor lacking the center is used to designate the target location e or the target position m. Needless to say, the number of lines is not limited to a cross.

  (C) is an example in which an arrow cursor is used to designate the target location e or target position m. Needless to say, it is not limited to an arrow, but may be a simple dot or another index. (D) is an example in which a rectangular cursor and the cross-shaped cursor described above are used in combination with the above-mentioned type (a) for specifying the target location e or target position m. Needless to say, there are various combinations and indicators.

  Incidentally, although the above (a) and (b) are difficult to specify the target position m accurately at the center, there is an advantage that the cursor does not hide the image around the target position m, and the above (c) and (d) ) Has an advantage that the target position m can be accurately specified at the center, although the cursor hides the image around the target position m.

<3> For more accuracy, the number of scout images may be determined by taking three or more images to determine the target position m, and the point is to obtain at least two different scout images.

<4> The ratio changing means H may be configured to move the main frame 10 with the chair 4b, that is, the subject O fixed in position.

<5> The scanning imaging means I may move the two-dimensional X-ray image sensor 2 vertically or obliquely, or may slide the X-ray generator 1 in parallel.

<6> In order to obtain the three-dimensional position of the target position m using a plurality of scout images, in addition to a click operation, that is, an artificial manipulation, various changes in the color tone and change in the condition of the affected area, etc. By inputting the conditions to the control device 7 in advance and providing a function for automatically recognizing a location with a certain degree of modulation as a target location, the target location is automatically determined from two or more scout images. It is also possible to adopt a control means (system) to be used.

These show the external appearance of a X-ray CT imaging apparatus, (a) is a front view, (b) is a side view. FIG. 2 is a basic configuration diagram of an X-ray CT imaging apparatus. These are operation | movement diagrams which show the preparation point of a scout image. Indicates the positioning procedure of the CT imaging location on the display monitor, (a) indicates the procedure for specifying the position with the horizontal cursor, and (b) indicates the procedure for specifying the position with the vertical cursor. Indicates a positioning procedure using two scout images having different shooting ratios, (a) shows a procedure for specifying a position with a horizontal cursor, and (b) shows a procedure for specifying a position with a vertical cursor. These are the schematic operation | movement diagrams which show the ratio expansion principle of a scout image. These are operation | movement diagrams which show the principle of a scanning imaging | photography means. These are operation | movement diagrams which show the concept of an imaging | photography area | region display control means. These are the flowcharts (the 1) which show a series of operation | movement from preliminary photography to main photography. These are the flowcharts (the 2) which show a series of operation | movement from a preliminary | backup photography to a main imaging | photography. These are the flowcharts (the 3) which show a series of operation | movement from preliminary photography to main photography. FIG. 4 is a flowchart showing a routine V. These are flowcharts which show the subroutine which calls a tomographic image from a fluoroscopic image. FIG. 9 is a flowchart showing a subroutine for calling a fluoroscopic image from a tomographic image. (A) is a conceptual diagram which shows the display of a fluoroscopic image, (b) is a conceptual diagram which shows the tomographic image of a target location. These are image display diagrams for conceptual understanding from fluoroscopic images to tomographic imaging. (A) is a figure which shows the example which cuts out an image to one direction, (b) is a figure which shows the example which cuts out a some image around an axial center. (A) is an example of a circular cursor, (b) is an example of a cross cursor lacking the center, (c) is an example of using an arrow cursor, and (d) is a square cursor and a cross cursor. It is an example used in combination.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray generator 2 Two-dimensional X-ray image sensor 3 Turning means 3a Turning center 4 Subject holding means 6 Arithmetic processing means 12 Ratio setting means A X-ray imaging means C Turning means drive control means D Preliminary imaging means E Display means F Position Adjustment means G Main photographing means H Ratio changing means I Scanning photographing means J Positioning operation means K Image storage means L Image calling means M Imaging area display control means N Position setting means

Claims (11)

An X-ray generator and a two-dimensional X-ray image sensor arranged opposite to the turning means are swung with respect to a subject located between the X-ray generator and the two-dimensional X-ray image sensor, and the object is moved locally. A local X-ray CT imaging apparatus configured to perform imaging by irradiating a site with an X-ray cone beam,
A control device and display means;
Preliminary imaging for imaging the subject under a plurality of positional conditions in which the positional relationship between the X-ray generator, the subject, and the two-dimensional X-ray image sensor is different from each other;
The display means simultaneously displays a plurality of fluoroscopic images obtained by the preliminary shooting, and displays an index for designating a target location on each of the plurality of fluoroscopic images,
The control device receives an operation of moving the index displayed on the display unit, moves the index displayed on each of the plurality of fluoroscopic images, and about the vertical direction of each of the plurality of fluoroscopic images, Moving an indicator to be displayed on each of the plurality of fluoroscopic images by an amount based on the imaging ratio of each of the plurality of fluoroscopic images;
Thus, the position adjustment for adjusting the positional relationship of the three members is performed so that the turning center of the turning means comes to the three-dimensional position of the subject at the subject.
After the position adjustment, a local X-ray CT imaging apparatus which performs main imaging for imaging a tomographic image of the subject by rotating the turning means with respect to the subject. The local X-ray CT imaging apparatus according to claim 1,
The local X-ray CT imaging apparatus in which the control device changes a ratio of an interval between the subject and the two-dimensional X-ray image sensor with respect to an interval between the X-ray generator and the two-dimensional X-ray image sensor. An X-ray generator and a two-dimensional X-ray image sensor arranged opposite to the turning means are swung with respect to a subject located between the X-ray generator and the two-dimensional X-ray image sensor, and the object is moved locally. A local X-ray CT imaging apparatus configured to perform imaging by irradiating a site with an X-ray cone beam,
Preliminary imaging means for performing preliminary imaging for imaging the subject under a plurality of positional conditions in which the positional relationship between the X-ray generator, the subject, and the two-dimensional X-ray image sensor is different from each other;
Display means for simultaneously displaying a plurality of fluoroscopic images obtained by the preliminary photographing means, and displaying an indicator for designating a target location on each of the plurality of fluoroscopic images;
Each of the plurality of fluoroscopic images is received in the vertical direction of each of the plurality of fluoroscopic images by an amount based on the imaging ratio of each of the plurality of fluoroscopic images in response to an operation of moving the index displayed on the display unit. Positioning operation means for moving an index to be displayed on
The positions of the three parties so that the turning center of the turning means comes to the three-dimensional position in the subject at the target location obtained from the position of each of the indices on the plurality of fluoroscopic images determined by the positioning operation means. Position adjusting means for adjusting the relationship;
After the position adjustment by the position adjustment means, the photographing means for photographing the tomographic image of the subject by turning the turning means relative to the subject;
A local X-ray CT imaging apparatus. In the local X-ray CT imaging apparatus of Claim 3,
A local X-ray CT imaging apparatus comprising ratio changing means capable of changing a ratio of an interval between the subject and the two-dimensional X-ray image sensor with respect to an interval between the X-ray generator and the two-dimensional X-ray image sensor. The local X-ray CT imaging apparatus according to claim 4,
A chair on which the subject to be a subject sits;
The local X-ray CT imaging apparatus in which the ratio changing unit changes the ratio by moving the chair. In the local X-ray CT imaging apparatus in any one of Claims 1-5,
Local X-ray imaging apparatus including a scanning imaging unit that performs imaging of the fluoroscopic image by the preliminary imaging while sliding the two-dimensional X-ray image sensor in a direction orthogonal to the X-ray cone beam irradiated from the X-ray generator. Line CT imaging device. In the local X-ray CT imaging apparatus in any one of Claims 1-6,
The first and second images in which the plurality of fluoroscopic images are photographed under two position conditions at which the X-ray generator and the two-dimensional X-ray image sensor form different angles with respect to the subject during the preliminary photographing. Is a perspective image of
The local X-ray CT imaging apparatus, wherein the vertical direction in which the index is moved in each of the first and second fluoroscopic images is a first direction that is a direction perpendicular to a plane in which the turning arm turns. The local X-ray CT imaging apparatus according to claim 7,
The index is a cursor displayed on the fluoroscopic image;
In response to the index movement operation, the cursor is moved in the first fluoroscopic image to set a position in a second direction different from the first direction, and then the cursor is moved in the second fluoroscopic image. Thus, the position in the third direction different from the first and second directions is set, and the position in the first direction is set by moving the cursor between the first and second fluoroscopic images. A local X-ray CT imaging apparatus that identifies the target location. In the local X-ray CT imaging apparatus in any one of Claims 1-8,
Image storage means for associating and storing the plurality of fluoroscopic images for defining the target location and the tomographic images of the target location determined from the fluoroscopic images;
When the target location of the subject in the fluoroscopic image selected from the fluoroscopic images stored in the image storage means and displayed on the display means is identified, the tomographic image of the identified target location is selected. The function of displaying by the display means and / or the tomogram displayed in the state where the tomographic image selected from the tomographic images stored in the image storage means is displayed by the display means Image calling means having a function of displaying the fluoroscopic image used for obtaining the position of the image;
A local X-ray CT imaging apparatus. In the local X-ray CT imaging apparatus in any one of Claims 1-9,
As the three-dimensional position is obtained, the local X includes a photographing area display control means for displaying the photographing area of the tomographic image related to the obtained three-dimensional position on the fluoroscopic image displayed on the display means. Line CT imaging device. An X-ray generator and a two-dimensional X-ray image sensor arranged opposite to the turning means are swung with respect to a subject located between the X-ray generator and the two-dimensional X-ray image sensor, and the object is moved locally. An image display method in a local X-ray CT imaging apparatus for irradiating a site with an X-ray cone beam and imaging a tomographic image of the subject,
The display means of the local X-ray CT imaging apparatus has a plurality of objects photographed under a plurality of positional conditions in which the positional relationship among the X-ray generator, the object, and the two-dimensional X-ray image sensor is different from each other. Displaying a fluoroscopic image at the same time, and displaying an indicator for designating a target location for determining a turning center of the turning means when taking the tomographic image on each of the plurality of fluoroscopic images;
When a movement operation of the index is received, a movement amount of the index to be displayed on the plurality of fluoroscopic images is calculated according to a shooting ratio between the plurality of fluoroscopic images, and the index is moved by the movement amount. By moving the vertical direction of each of the plurality of fluoroscopic images,
An image display method in a local X-ray CT imaging apparatus comprising:

Images