JP2008114083A - X-ray diaphragm and x-ray imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray imaging apparatus which can reduce burden on its operator and can be widely used. <P>SOLUTION: A switching mechanism 12 for this X-ray imaging apparatus allows a lower limbs imaging filter 11a to move into an X-ray irradiation field, or an opening 10a of an X-ray movable diaphragm 10 only in imaging a region on the foot side lower than the inguinal region of a subject, and also allows the filter 11a to move out of the irradiation field in imaging the waist region. This constitution of the switching mechanism 12 reduces the burden on the operator to realize a highly versatile X-ray imaging apparatus. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an X-ray imaging apparatus that detects an X-ray irradiated to an object from an X-ray tube and images the object, and an X-ray diaphragm used for the X-ray imaging apparatus, and in particular, extracts an X-ray component. The present invention relates to a technique for performing X-ray imaging using a filter.

Conventionally, in an X-ray imaging apparatus, for example, when performing angiographic imaging of the lower limbs on both feet simultaneously, a contrast agent is injected into the blood vessel of the subject, A holding member (for example, a C-type arm) that holds an X-ray tube and an X-ray detector (image intensifier) of the X-ray apparatus or a top plate on which the subject is placed is continuously moved or stepped from the waist to the toes. (For example, refer to Patent Document 1).
JP 2001-269333 A

However, when imaging is performed using a filter that extracts an X-ray component in a conventional X-ray imaging apparatus, there is a problem that the burden on the operator or imaging becomes difficult. For example, as described above, when angiography of the lower limbs is performed simultaneously on both feet, halation occurs in the captured image because the X-ray transmittance is different between the foot portion and the portion between both feet. If a dedicated mat is placed between both feet of the subject in order to prevent such halation, the burden on the operator increases due to the mat. In addition, it may be possible to prevent halation by installing a filter in the vicinity of the tube of the X-ray tube. However, in this case, the center of the photographed image of the waist is hidden by the filter, making photographing difficult.

The present invention has been made in view of such circumstances, and it is an object of the present invention to reduce the burden on the operator and to provide a versatile X-ray imaging apparatus.

In order to achieve such an object, an X-ray diaphragm device according to the present invention includes a filter for extracting an X-ray component, a lower limb imaging filter provided with a filter that suppresses the transmittance of X-rays at the center, And switching means for switching the filter or the lower limb imaging filter between an X-ray irradiation field and an irradiation field.

The switching mechanism includes a base gear provided with a filter for extracting the X-ray component and the lower limb imaging filter, a drive gear and a position detection gear respectively fitted to the base gear, and the base gear. A base shaft that passes through the center of the drive gear, a drive shaft that passes through the center of the drive gear, a detection shaft that passes through the center of the position detection gear, and a motor that rotates the drive shaft about the axis. And a tachometer connected to the bottom of the detection shaft.

Further, the filter for extracting the X-ray component is composed of three additional filters that respectively adjust the amount of X-ray transmission, and the additional filter and the lower limb imaging filter are arranged at 90 ° intervals on the base gear. It is characterized by.

Note that the present specification also discloses an invention relating to an X-ray imaging apparatus, an X-ray imaging method, and an X-ray tube used in the X-ray imaging apparatus.

(1) An X-ray imaging method that performs X-ray imaging of a subject by irradiating the subject with X-rays from an X-ray tube and detecting the X-rays irradiated on the subject with an X-ray detector. Then, at least one of the holding member that holds the X-ray tube and the X-ray detector or the top plate on which the subject is placed is moved, and the relative position between the holding member and the top plate is a predetermined position. Only when the filter for extracting the X-ray component irradiated from the X-ray tube is moved into the X-ray irradiation field, and when the relative position is other than the predetermined position, the filter is moved out of the irradiation field. An X-ray imaging method characterized by performing X-ray imaging of a subject.

[Operation / Effect] According to the invention of (1) above, in order to obtain a photographed image relating to the predetermined position using the filter, the filter is moved into the irradiation field only at the predetermined position, so that the filter passes through the filter. In order to perform X-ray imaging of the subject at the predetermined position and acquire a captured image relating to other than the predetermined position without using the filter, the filter is moved by moving outside the irradiation field at a position other than the predetermined position. X-ray imaging of the subject at a position other than the predetermined position is performed without passing. As a result, for example, it is possible to reduce the burden on the operator such as placing a mat on the subject as in the past, and further, it is possible to select whether to use a filter depending on the position of imaging, Shooting is easy.

(2) In the X-ray imaging method according to (1), the filter is moved between the X-ray irradiation field and the irradiation field by selecting and switching from the plurality of filters to a predetermined filter. X-ray imaging method characterized by the above.

[Operation / Effect] According to the invention of (2), the filter is moved between the X-ray irradiation field and the irradiation field by selecting and switching from the plurality of filters to the predetermined filter. X-ray imaging can be performed using various filters.

(3) An X-ray tube used in an X-ray imaging apparatus, wherein the X-ray tube includes a filter that extracts an X-ray component emitted from the X-ray tube, and an X-ray emitted from the X-ray tube. A moving means for moving the filter between the irradiation field and the irradiation field, and the relative position between the holding member for holding the X-ray tube and the X-ray detector and the top plate on which the subject is placed The moving means is configured to move the filter into the illumination field only when it is at a predetermined position, and to move the filter out of the illumination field when the relative position is other than the predetermined position. X-ray tube.

An X-ray tube that irradiates a subject with X-rays, an X-ray detector that detects X-rays irradiated to the subject, a holding member that holds the X-ray tube and the X-ray detector, and a subject The top plate to be placed, a filter for extracting an X-ray component irradiated from the X-ray tube, and the filter is moved between an irradiation field outside and an irradiation field of the X-ray irradiated from the X-ray tube. An X-ray imaging apparatus comprising a moving means, wherein the filter is moved into the illumination field only when the relative position between the holding member and the top plate is a predetermined position, and the relative position is other than the predetermined position. In this case, the moving means is configured to move the filter out of the illumination field.

[Operation / Effect] The moving means is configured to move the filter between the irradiation field of the X-rays irradiated from the X-ray tube and the irradiation field, and the relative position between the holding member and the top plate. The filter is moved into the illumination field only when is in a predetermined position, and the filter is moved out of the illumination field when the relative position is other than the predetermined position. Therefore, in order to obtain a captured image relating to the predetermined position using the filter, the moving means moves the filter into the irradiation field only at the predetermined position, so that the X-ray of the subject at the predetermined position is passed through the filter. In order to take a photograph and obtain a photographed image at a position other than the predetermined position without using a filter, the moving means moves outside the irradiation field at a position other than the predetermined position. X-ray imaging of the subject at. As a result, for example, it is possible to reduce the burden on the operator such as placing a mat on the subject as in the past, and further, it is possible to select whether to use a filter depending on the position of imaging, Imaging becomes easy, and a highly versatile X-ray imaging apparatus can be realized.

(5) The X-ray tube according to (3), wherein the filter limits the X-ray bundle irradiated from the X-ray tube to a predetermined shape.

The filter (3) is not particularly limited, and may be a filter that limits the X-ray bundle irradiated from the X-ray tube to a predetermined shape as in the invention (5).

(6) The X-ray tube according to (3) or (5), wherein the moving unit is configured by a switching unit that selectively switches from a plurality of the filters to a predetermined filter. .

[Operation / Effect] According to the invention of (6), the moving means is constituted by the switching means for selecting and switching from a plurality of filters to a predetermined filter, so Move the filter between. With this configuration, X-ray imaging can be performed using various filters.

When photographing both feet, X-rays are irradiated to the foot portion of the subject M corresponding to a portion other than the central portion of the lower limb photographing filter, and between the two feet corresponding to the central portion of the lower limb photographing filter. The portion is hardly irradiated with X-rays, and the difference in X-ray transmittance between the foot portion and the portion between both feet is reduced. As a result, halation does not occur, so the burden on the operator such as placing a mat on the subject M to prevent halation can be reduced. Also, X-ray imaging can be performed using various filters.

The filter is not particularly limited as long as it extracts only X-rays of specific energy from different X-ray qualities for each X-ray wavelength, that is, extracts X-ray components. It is a filter that limits the irradiated X-ray beam to a predetermined shape. “Restrict to a predetermined shape” means that, for example, the X-ray transmittance is increased within a predetermined shape, and the X-ray transmittance is decreased or the X-ray is not transmitted outside the shape. For example, the X-ray transmittance may be increased outside the predetermined shape, and the X-ray transmittance may be decreased or not transmitted through the shape.

In addition, the moving unit may be configured by a switching unit that selects and switches from a plurality of filters to a predetermined filter, so that the filter may be moved between the X-ray irradiation field and the irradiation field. Also, with this configuration, X-ray imaging can be performed using various filters.

An embodiment of the present invention will be described below with reference to the drawings. 1 is a side view showing a schematic configuration of an X-ray imaging apparatus according to the present embodiment, FIG. 2 is a front view thereof, and FIG. 3 is an X-ray tube used in the X-ray imaging apparatus according to the present embodiment. FIG. 4 is a plan view of those collimators, FIG. 4 is a plan view thereof, and FIG. 5 is a plan view of a switching mechanism provided in the collimator. In this embodiment, an X-ray imaging apparatus that takes a blood vessel image by injecting a contrast medium into a subject via a contrast medium injection catheter will be described as an example. As shown in FIGS. 1 and 2, the apparatus according to this embodiment includes a top plate 1, a support column 2, and a C-type arm 3 on which a subject M is placed and examined. This support | pillar part 2 is attached to the ceiling surface, and is fixing except rotation around the axis of a vertical axis (z axis in FIG. 1, FIG. 2). The C-type arm 3 corresponds to the holding member in the present invention.

The top plate 1 is configured to be movable up and down and movable along the body axis direction of the subject M. A top plate drive control unit 4 that controls the driving of the top plate 1 is connected to the top plate 1, and this top plate drive control unit 4 includes a drive mechanism that drives the top plate 1 and a body axis of the top plate 1. It is configured to control a brake mechanism that stops movement in the direction, a brake release mechanism that releases movement in the body axis direction, a detection mechanism that detects the position of the top plate 1, and the like (all not shown).

An X-ray tube 5 that irradiates the subject M with X-rays is provided at one end of the C-arm 3, and an image intensity that detects and converts the X-rays applied to the subject M to an optical image at the other end. Fires (hereinafter abbreviated as “I.I” where appropriate) 6 are supported. The C-arm 3 is an axis (FIG. 1, FIG. 2) that is horizontal and perpendicular to the body axis of the subject M around the body axis of the subject M (x axis in FIGS. 1 and 2). The y-axis is configured to be rotatable around the center axis of the middle y-axis), and the support column 2 is configured to be rotatable about the vertical axis. I. I6 corresponds to the X-ray detector in the present invention.

A C-type arm drive control unit 7 for controlling the driving of the column part 2 and the C-type arm 3 is connected to the column part 2 and the C-type arm 3, and the C-type arm drive control unit 7 is connected to the column part 2. And a drive mechanism for driving the C-type arm 3 and a detection mechanism for detecting the positions of the support column 2 and the C-type arm 3 (both not shown).

A high voltage generator 8 that applies a tube voltage and a tube current to the X-ray tube 5 is connected to the X-ray tube 5. As shown in FIGS. 3 and 4, a collimator 9 is attached to the X-ray tube 5 in a direction in which X-rays are emitted, and the collimator 9 controls the irradiation field of X-rays. The collimator 9 includes an X-ray movable diaphragm 10 including four plate members 10 a and a switching mechanism 12 having a plurality of filters 11. The collimator 9 corresponds to the X-ray diaphragm device in the present invention.

The four plate-like members 10a constituting the X-ray movable diaphragm 10 are arranged orthogonal to each other so as to have an opening 10b, and each plate-like member 10a is arranged in the direction of the arrow in FIGS. Each is configured to be movable. The X-ray passing through the opening 10b becomes an X-ray illumination field, and each plate-like member 10a is configured to be movable as described above, thereby adjusting the size of the opening 10b. Adjust the X-ray illumination field.

As shown in FIGS. 1 and 2, the collimator drive control unit 13 that controls the drive of the plate-like member 10 a and the switching mechanism 12 (see FIGS. 3 and 4) of the collimator 9 includes the plate-like member 10 a and the switching mechanism 12. The collimator drive control unit 13 is connected to each other, and the collimator drive control unit 13 determines the position of the drive mechanism (not shown) that drives the plate-like member 10a, the motor 22 that drives a base gear 16 (to be described later) of the switching mechanism 12, and the filter 11. The tachometer 23 to be detected is controlled. A specific configuration of the switching mechanism 12 will be described later.

I. The data converted into an optical image by I6 is sent to the calculation unit 15 via the control unit 14, and after being subjected to various calculation processes, is output as a captured image. The control unit 14 is configured to control the top plate drive control unit 4, the C-arm drive control unit 7, the high voltage generation unit 8, the collimator drive control unit 13, and the like. In addition to the calculation processing described above, the calculation unit 15 also has a function of calculating the relative position between the C-type arm 3 and the top plate 1 based on the positions of the C-type arm 3 and the top plate 1.

Next, a specific configuration of the switching mechanism 12 will be described with reference to FIGS. The switching mechanism 12 includes a base gear 16 provided with a plurality of filters 11, a drive gear 17 and a position detection gear 18 that are respectively fitted to the base gear 16, and a base shaft that passes through the center of the base gear 16. 19, a drive shaft 20 that passes through the center of the drive gear 17, a detection shaft 21 that passes through the center of the position detection gear 18, a motor 22 that rotates the drive shaft 20 around its axis, and a detection shaft 21 And a tachometer 23 connected to the bottom of the.

Further, in this embodiment, the filter 11 disposed in the base gear 16 is a lower limb photographing filter that limits the X-ray bundle irradiated from the X-ray tube 5 to a “R” shape as shown in FIG. 11a and three additional filters 11b for adjusting the amount of X-ray transmission. The lower limb imaging filter 11a is provided with a rectangular filter 11c having a low X-ray transmittance in the vicinity of the center, so that the X-ray bundle transmitted through the lower limb imaging filter 11a is limited to a "B" shape. .

When the motor 22 rotates the drive shaft 20 around the axis, the drive gear 17 is driven to rotate, and the base gear 16 fitted to the drive gear 17 is also driven to rotate. The filters 11 a and 11 b disposed on the base gear 16 are rotated around the axis of the base shaft 19 in the direction of the arrow in FIG. Further, the rotation speed of the position detection gear 18 fitted to the base gear 16 is measured by the tachometer 23 via the detection shaft 21, so that each filter 11a rotated in the direction of the arrow in FIG. , 11b are detected.

As shown in FIG. 4, the filters 11 a and 11 b move between the outside and inside of the opening 10 b of the X-ray movable diaphragm 10 by rotating the base gear 16, that is, between the X-ray irradiation field and the irradiation field. Move between. Further, by rotating the base gear 16 by 90 °, the four filters 11 (lower limb photographing filter 11a and additional filter 11b) are selected and switched to predetermined filters. Therefore, the switching mechanism 12 corresponds to the moving means in the present invention and also corresponds to the switching means in the present invention.

Next, an X-ray imaging method related to angiography of the lower limb will be described with reference to the flowchart of FIG. In the present embodiment, the state in which the contrast medium flows inside the blood vessel is imaged in the order from the waist to the toes.

(Step S <b> 1) Moving the top plate After placing the subject M on the top plate 1, the subject M is moved up and down while placing the subject M so that the height of the top plate 1 is at a predetermined position. The waist of the subject M is connected to the X-ray tube 5 of the C-arm 3 and the I.V. The top board 1 moves along the body axis direction of the subject M so as to be positioned between I6 and I6.

(Step S2) The waist of the imaging subject M at the waist is connected to the X-ray tube 5 of the C-arm 3 and the I.V. When it is positioned between I6 and the waist, photographing of the waist is started. At this time, as shown in FIG. 5 (a), the additional filter 11b other than the lower limb imaging filter 11a is positioned within the X-ray irradiation field, that is, the lower limb imaging filter 11a is positioned outside the irradiation field, At the time of imaging, X-rays are transmitted through the additional filter 11b in the illumination field. More specifically, the X-ray tube 5 emits X-rays, and the subject M is irradiated via the additional filter 11 b in the collimator 9 and the X-ray movable diaphragm 10. X-rays irradiated to the subject M After the detection by I6 and conversion into an optical image, the converted data is sent to the calculation unit 15 via the control unit 14, and after performing various calculation processes, a photographed image of the waist is obtained. In this embodiment, the purpose is to examine how the contrast medium flows inside the blood vessel, so that the diagnosis result is displayed on a TV monitor (not shown) without actually acquiring the captured image. .

The top 1 moves in the direction of the head of the subject M so as to obtain a photographed image from the waist to the toes while examining the photographed image of the waist. Then, the captured images are obtained in order while moving.

(Step S3) Filter switching The vicinity of the buttocks (groin root) of the subject M is the X-ray tube 5 of the C-arm 3 and the I.D. When reaching the position between I 6 and I 6, the switching mechanism 12 switches the filter 11. That is, the relative positions of the holding member and the top plate in the present invention are the same as the X-ray tube 5 of the C-arm 3 and the I.D. It shows the relative position between the C-arm 3 and the top board 1 where the part on the toe side of the buttocks of the subject M is located between I6 and I6.

At the time of switching, the additional filter 11b in the illumination field rotates in the direction of the arrow in FIG. 5B and moves outside the illumination field as shown in FIG. The lower limb photographing filter 11a rotates in the same direction and moves into the irradiation field as shown in FIG. As a result, the lower limb photographing filter 11a is selected and switched. Since the tachometer 23 detects the position of each filter 11, it can be controlled so that the lower limb imaging filter 11a is positioned in the irradiation field.

(Step S4) After switching to the both-foot shooting lower limb shooting filter 11a, shooting of both legs is started. When photographing both feet, X-rays are transmitted through the lower limb photographing filter 11a in the irradiation field. More specifically, among the X-ray bundles irradiated from the X-ray tube 5, X-rays near the center are hardly transmitted by the rectangular filter 11c near the center of the lower limb imaging filter 11a, and other than that. Part of the x-rays are transmitted. As a result, the X-ray bundle that has passed through the lower limb imaging filter 11a is irradiated to the subject M in a state of being limited to a "B" shape. Accordingly, the part of the foot of the subject M corresponding to the position of the “L” of the lower limb imaging filter 11a is irradiated with X-rays, and the part between both feet corresponding to the vicinity of the center of the lower limb imaging filter 11a. Is hardly irradiated with X-rays.

Similar to the imaging of the lower back in step S2, diagnosis is performed by displaying the captured images of both feet on the TV monitor based on the X-ray data irradiated to both feet of the subject M.

The top 1 moves in the direction of the head of the subject M so as to obtain a captured image from the buttocks toward the toes while examining the captured images of both feet. Then, the captured images are obtained in order while moving.

When the captured image is obtained up to the tip of the foot, the top 1 moves along the body axis direction of the subject M while the subject M is placed so as to avoid the C-arm 3. Then, after the top plate 1 is moved up and down, the subject M is lowered from the top plate 1 and a series of X-ray imaging is completed.

According to the series of X-ray imaging methods according to steps S1 to S4 described above, in order to obtain a captured image of both feet using the lower limb imaging filter 11a in step S4, the lower limb imaging is performed only when imaging both feet in step S3. By moving the filter 11a into the irradiation field, X-ray imaging of both feet of the subject M is performed through the filter 11a, and the image of the lower back is taken in step S2, for example, other than both feet without using the filter 11a. In order to acquire, X-ray imaging of the waist of the subject M is performed without moving through the filter 11a by moving the filter 11a out of the irradiation field.

Further, according to the present embodiment apparatus, the switching mechanism 12 is configured to move each filter 11 between the irradiation field of the X-rays irradiated from the X-ray tube 5 and the irradiation field, and When the relative position between the C-type arm 3 and the top plate 1 is a predetermined position, the X-ray tube 5 of the C-type arm 3 and the I.D. When the relative position between the C-arm 3 and the top plate 1 is located between the I-axis and the buttocks of the subject M, the lower-limb imaging filter 11a is within the irradiation field. When the relative position is other than the predetermined position, the filter 11a is moved out of the irradiation field.

Further, in the case of the present embodiment, when photographing both feet, X-rays are irradiated to the foot portion of the subject M corresponding to the position of the "L" of the lower limb photographing filter 11a, and the lower limb photographing is performed. The portion between the two feet corresponding to the vicinity of the center of the filter 11a is hardly irradiated with X-rays, and the difference in X-ray transmittance between the foot portion and the portion between both feet is reduced. As a result, halation does not occur, so the burden on the operator such as placing a mat on the subject M to prevent halation can be reduced.

In addition, when imaging the lower back other than the legs of the subject M, for example, the additional filter 11b is used in place of the lower limb imaging filter 11a, the rectangular shape in the lower limb imaging filter 11a is at the center of the lower limb imaging image. The filter 11c is not hidden. As a result, it is possible to select whether or not to use the lower limb imaging filter 11a according to the imaging position, so that imaging is facilitated and a highly versatile X-ray imaging apparatus can be realized.

In this embodiment, the switching mechanism 12 is configured by means for selecting and switching from the four filters 11 to the predetermined lower limb imaging filter 11a, so that X-ray imaging can be performed using various filters.

The present invention is not limited to the above-described embodiment, and can be modified as follows.

(1) In the present embodiment described above, a contrast medium is injected into a subject through a contrast medium injection catheter, and the state of the contrast medium flowing through the blood vessel is diagnosed, but before and after the catheter injection. It can also be applied to digital subtraction angiography in which subtraction processing is performed on each of the captured images. Further, the present invention can also be applied to an X-ray imaging apparatus that does not inject a catheter and that simply images or diagnoses X-ray imaging or an X-ray CT apparatus.

(2) In the present embodiment described above, the filter 11 to be switched is the lower limb photography filter 11a and the additional filter 11b, but is not limited to these filters 11a and 11b. Alternatively, the base gear 16 may be provided with only the lower limb imaging filter 11a, and X-ray imaging may be performed without passing through other filters when the filter 11a is not used.

(3) In the present embodiment described above, the switching mechanism 12 is used as the moving means in the present invention, and the switching mechanism 12 in the present invention is further provided with the switching mechanism 12 in the present invention. It is not limited to such a switching mechanism 12. For example, as shown in the cross-sectional view of FIG. 7, a plurality of filters 31 are arranged on the belt 30, and the filters 31 are selected and switched by moving the belt 30 in the direction of the arrow in FIG. It may be configured.

In addition, the function of the switching unit is not necessarily provided. As described in the modification (2), the base gear 16 may be provided with only the lower limb photographing filter 11a so that the lower limb photographing filter 11a is moved between the illumination field and the illumination field. Instead of the base gear 16 of this embodiment, as shown in the plan view of FIG. 8, only one filter 41 is disposed on the base 40 that moves in the horizontal direction, and the base 40 moves in the horizontal direction. Thus, the filter 41 may be moved between the illumination field and the illumination field.

(4) In the present embodiment described above, the switching mechanism 12 that is the moving means in the present invention is provided in the collimator 9 that is the X-ray diaphragm device in the present invention, but the moving means in the present invention is provided in the X-ray tube 5. May be.

(5) In the present embodiment described above, the C-type holding member 3 provided with the C-type arm 8 is used as the holding member in the present invention, but any member that holds the X-ray tube and the X-ray detector can be used. There is no particular limitation.

It is the side view which showed schematic structure of the X-ray imaging apparatus which concerns on a present Example. It is the front view which showed schematic structure of the X-ray imaging apparatus which concerns on a present Example. It is a partially broken view of the X-ray tube and collimator used for the X-ray imaging apparatus which concerns on a present Example. It is a top view of the X-ray tube and collimator which concern on a present Example. It is a top view of the switching mechanism with which the collimator which concerns on a present Example was equipped, Comprising: (a) shows the one aspect | mode before a filter switches, (b) shows the aspect when a filter switches. It is a flowchart which shows a series of X-ray imaging methods which concern on the angiography imaging | photography of a leg. It is sectional drawing of the switching mechanism which concerns on a modification. It is a top view of the switching mechanism concerning the further modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Top plate 3 ... C-type arm 5 ... X-ray tube 6 ... Image intensifier (II)
9 ... Collimator 11 ... Filter 12 ... Switching mechanism M ... Subject

Claims (4)

  A filter for extracting an X-ray component, a lower limb imaging filter provided with a filter with reduced X-ray transmittance at the center, and the filter or the lower limb imaging between an X-ray irradiation field and an irradiation field An X-ray diaphragm apparatus comprising switching means for switching a filter for use. The switching mechanism includes a base gear provided with a filter for extracting the X-ray component and the lower limb imaging filter, a drive gear and a position detection gear respectively fitted to the base gear, and a center of the base gear. A base shaft that penetrates the center, a drive shaft that penetrates the center of the drive gear, a detection shaft that penetrates the center of the position detection gear, a motor that rotates the drive shaft about an axis, and The X-ray diaphragm device according to claim 1, further comprising a tachometer connected to a bottom portion of the detection shaft.   The filter for extracting the X-ray component is composed of three additional filters that respectively adjust the amount of X-ray transmission, and the additional filter and the lower limb imaging filter are arranged at 90 ° intervals on the base gear. The X-ray diaphragm apparatus according to claim 2. An X-ray tube, the X-ray diaphragm apparatus according to any one of claims 1 to 3, an X-ray detector, a holding member that holds the X-ray tube and the X-ray detector, and a subject are placed X-ray imaging apparatus having a top plate to be operated.

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