JPH0514239Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention is based on an X-ray fluoroscopic imaging apparatus having an image intensifier, and when an X-ray beam is incident on the circular input surface of the image intensifier, When injecting the X-ray flux into the corresponding circular or polygonal irradiation field onto the imaging film,
X-rays emitted from the X-ray tube so as to form corresponding square or rectangular radiation fields, respectively.
This invention relates to an X-ray constriction device that constricts a beam cone.

(b) Prior art In an X-ray fluoroscopic imaging device equipped with an image intensifier (hereinafter abbreviated as II), each pair of rectangular diaphragm pieces 11 and 11' are arranged parallel to each other as shown in FIG. In an aperture device that constricts the X-ray cone into a rectangular or square shape by moving the aperture pieces 11 and 11' in the directions of the arrows, the input surface of II has a diameter as shown in Fig. 6. Since is a circle of d,
Even if the X-ray cone is narrowed down to form a square irradiation field with one side d on this input surface, the shaded area that does not participate in the formation of the X-ray fluoroscopic image will cause excess radiation exposure to the patient. will give. Therefore, in order to obtain a circular irradiation field, eight aperture pieces 1 as shown in Figure 7 were used.
A regular octagonal aperture formed by sequentially overlapping elements a, 1b...1h may be used. However, each diaphragm piece 1a, 1b...1h of this diaphragm needs to be made from a lead plate with a thickness of 2 to 3 mm in order to completely shield the X-ray beam. As is clear from Fig. 8, the aperture piece 1 is far away from the focal point F of the X-ray tube.
a and the aperture piece 1h which is close to the focal point F, including the gap between them for movable each aperture piece, is 16 to 24 mm or more (a-b>14 to 21
mm) distance differences inevitably occur. As a result, a regular octagonal X-ray irradiation field cannot be obtained with the diaphragm having a regular octagonal shape in the plan view of FIG. 7, but a distorted octagonal irradiation field is formed.

Also, in order to reduce the aperture area of this diaphragm,
When each aperture piece 1a, 1b...1h is rotated by the same angle clockwise around the rotation pin 2, the aperture area becomes smaller, but at the same time the distorted octagonal irradiation field is The diaphragm pieces are rotated clockwise around the diaphragm by the rotation angle.

Thus, in conventional aperture devices, a distorted polygonal illumination field and, when it is constricted, a distorted polygonal rotated field is formed, and the image is monitored within such an illumination field. Since it was shown on TV, there was a problem in that it was difficult to view and lowered the value of the product.

(C) Purpose This invention solves the above-mentioned problems in conventional X-ray diaphragm devices and provides an X-ray diaphragm device that can more accurately form rectangular, square, and approximately circular irradiation fields. The purpose is to

(D) Structure The X-ray diaphragm device according to this invention consists of X-ray opaque plates that are movable toward and away from each other in directions perpendicular to their respective longitudinal directions while maintaining a parallel relationship with each other. The rectangular diaphragm is constructed by combining a pair of rectangular diaphragm pieces in a cross-shaped pattern, and the rear end is rotatably supported around one point, and the inner side near the tip is arc-shaped or curved. It is constructed by combining a plurality of swinging aperture pieces made of X-ray opaque plate material shaped into a curved shape, and has its aperture center on the center line of the X-ray beam emitted from the X-ray tube, and its maximum circular aperture is characterized in that a circular aperture larger than the maximum rectangular aperture of the rectangular aperture is arranged in parallel in the irradiation direction of the X-ray beam. In the X-ray diaphragm device according to this invention, a circular irradiation field can be obtained with both the rectangular diaphragm and the circular diaphragm during II fluoroscopy, and a square or rectangular irradiation field can be obtained with the rectangular diaphragm during imaging. Furthermore, regarding the circular irradiation field, since the inner side of the swinging diaphragm piece near the tip is shaped into an arc or a curved line including an arc, an irradiation field that is approximately circular is formed.

(e) Embodiment FIG. 1 is an exploded perspective view showing the configuration of an X-ray diaphragm that is an embodiment of this invention. In this embodiment device, a conventional rectangular diaphragm 10 whose external plan view is shown in FIG. 2 and a circular diaphragm 20 whose external plan view is shown in FIG. As shown in FIG. 5, which is a schematic side cross-sectional view of this device taken along the side cross-section V-V that crosses O, O', the centers O and O' of each aperture plane are wire tube 3
The X-ray beams are placed in a hollow rectangular frame 4 with the upper and lower parts arranged so that the center line of the X-ray beam passes from the bottom to the top. The housing 4 is provided with an X-ray shielding cone 5 made of lead material at the connection part with the X-ray tube 3, and the X-ray beam is made to enter the interior through the opening.

As shown in the upper part of FIG. 1, each pair of rectangular apertures 10 is provided in the housing 4 so as to be slidable in a direction perpendicular to the respective longitudinal directions while maintaining a parallel relationship with each other. A rectangular vertical drawing piece 11 and a horizontal drawing piece 11' made of lead plate material with a diameter of about 2 mm.
It is constructed by combining them in a parallel grid pattern. The pair of vertical throttle pieces 11 are shown on an endless timing belt 15 that is stretched around a drive pulley 13 driven by a motor 12 and a driven pulley 14 that is positioned parallel to the drive pulley 13 and the horizontal throttle piece 11'. They are connected via connecting members as shown in the figure. A gear 16 is attached to the output shaft of the motor 12, and a potentiometer 18 is attached to the rotating shaft of a gear 17 meshed with the gear 16. A pair of horizontal drawing pieces 11'
is connected to a drive pulley 13' which is also driven by the motor 12' and an endless timing belt 15' which is stretched around a driven pulley 14' which is located parallel to the vertical throttle piece 11 together with this drive pulley 13'. They are connected to each other via members. A gear 16' is attached to the output shaft of the motor 12', and a potentiometer 1 is attached to the rotating shaft of a gear 17' meshed with this gear 16'.
8' is installed.

Therefore, if the output shaft of the motor 12 is driven to rotate clockwise when viewed from above, the vertical throttle pieces 11 will be moved in parallel so that they approach each other, and if the motor 12' is also driven to rotate counterclockwise, ,
Since the horizontal aperture pieces 11' are moved in parallel so as to approach each other, the longitudinal aperture pieces 11'
The rectangular irradiation field formed by each pair of horizontal aperture pieces 11' can be narrowed down. The illustrated aperture pieces 11, 11' are shown in FIG.
The irradiation field formed on the input surface of the input surface is maintained at an opening that forms a square circumscribing the circular portion of the input surface.
Therefore, by bringing only one pair of the vertical aperture pieces 11 or the horizontal aperture pieces 11' close to each other, a rectangular irradiation field can be formed. The aperture opening, that is, the size of the irradiation field, and its shape are determined by the vertical aperture piece 11 and the horizontal aperture piece 1.
The motors 12, 12' are rotated by a signal corresponding to the rotation angle amount including the rotation direction from the reference position of the potentiometers 18, 18' which is proportional to the translation amount including the movement direction of the potentiometers 1'. You can control and change the stops individually.

The circular diaphragm 20 is rotatably supported in the housing 4 in the vicinity of the rectangular diaphragm 10, with the center line of the X-ray beam as the rotation axis, and the rectangular diaphragm 10 is formed at the maximum opening. A driving disk 21 having a circular opening larger than a square opening and having a gear on the outer periphery.
The drive disk 21 is provided with four guide slots 22 whose longitudinal direction is in the radial direction, and which are equally spaced around the center of the drive disc 21.
A swinging aperture piece 24 made of a lead plate material with a thickness of about 2 mm has a guide pin 23 slidably inserted into the support arm 2 fixed near the tip thereof, and a support arm 24 made of a lead plate material with a thickness of about 2 mm is attached to a support arm provided in the housing 4 near the rear end. (not shown) are connected by pins so that they do not interfere with each other, and as shown in the plan view of FIG. As shown in FIG. It is designed to create a slightly larger circular field. For this purpose, these four swinging aperture pieces 24 are moved clockwise in FIG.
If we decide to name these oscillating aperture pieces 24
a, 24b, 24c, and 24d are all formed into arcuate surfaces having a length R from the tip of the inner surface, and the swinging aperture pieces 24b, 24d are the upper surface of the drive disk 21, and the swinging aperture pieces The pieces 24a and 24c are supported in a cantilevered manner by connecting pins 25 on surfaces that are parallel to the upper surface of the driving disk 21 and spaced apart by the thickness of the swinging aperture piece 24, so as to be able to swing freely. There is.

The outer periphery of the drive disk 21 is a gear 26, and a pinion 28 fixed to the output shaft of a motor 27 is meshed with the gear 26.

Since the circular diaphragm 20 is configured in this way, when the output shaft of the motor 27 is rotated clockwise when viewed from above, the drive disk 21 is rotated counterclockwise by the pinion 28. , as the driving disk 21 rotates, the swinging aperture piece 24a, which is engaged with the guide slot 21 via the guide pin 23,
24b, 24c, and 24d are simultaneously rotated counterclockwise around their respective connecting pins 25,
If the output shaft of the motor 27 is rotated counterclockwise, contrary to the above, the swinging aperture pieces 24a, 24
b, 24c, and 24d are simultaneously rotated clockwise around their respective connecting pins 25. In this way, the drive disk 21 is driven by the motor 27.
When the diaphragm pieces 24a and 24a are rotated counterclockwise and clockwise, respectively, the oscillating aperture pieces 24a,
24b, 24c, and 24d each have an inner periphery formed by the arcuate surface expanded or narrowed, so that the X-ray beam passing therethrough forms an approximately circular irradiation field of varying size. Form.

The opening degree of the diaphragm, that is, the size of the irradiation field, and its shape, ie, the degree of circular approximation, depend on the swing angle including the swing direction of each swing diaphragm piece 24. Since the swing angle including the swing direction of each swing throttle piece 24 is proportional to the swing angle including the swing direction of the drive disk 21, the same pinion 29 as the pinion 28 is connected to the drive disk 21. If the potentiometer 30 is engaged with the gear 26 forming the outer circumference of the motor 27 and the potentiometer 30 is attached to the rotating shaft, the motor 27 will be activated by a signal corresponding to the rotation angle including the rotation direction from the reference position of the potentiometer 30. By controlling the rotation and stopping of the irradiation field, the size and shape of the approximately circular irradiation field can be changed.

The irradiation field formed on the circular input surface II by the X-ray beam passing through this circular aperture 20 is the X-shaped shaded portion in FIG. 4, and as can be seen from the outline, the X-ray beam spreads outward from the small gaps present between the circular arcs, but this is suppressed by using the rectangular aperture 10 described above in combination.

Further, this circular diaphragm 20 has a swinging diaphragm piece 24.
Connecting pin 2 in the counterclockwise direction when viewed from above.
5 and maximize the opening degree, the rectangular diaphragm 10 can be rotated to the maximum extent so as not to interfere with the irradiation field obtained by the rectangular diaphragm 10.

Therefore, in this device, the circular aperture 20
If the diaphragm is retracted as described above, the rectangular diaphragm can be used for film photography, and the circular diaphragm 20 alone or in combination with the rectangular diaphragm 20 can be used.
Irradiation fields suitable for both fluoroscopy using II and spot imaging using II can be formed.

(F) Effect The X-ray aperture device according to this invention is configured by combining two types of apertures, a rectangular aperture and a circular aperture, so during II fluoroscopy, a circular irradiation field can be
Furthermore, during imaging, square or rectangular angular irradiation fields can be formed, and for circular irradiation fields, it is possible to form irradiation fields that more closely resemble a circle.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing the configuration of an X-ray aperture device that is an embodiment of this invention, Fig. 2 is an external plan view of a rectangular aperture of this embodiment, and Fig. 3 is a circular aperture of the same. 4 is a plan view of the irradiation field formed on the input surface of the image amplifier amplifier by this embodiment device, FIG. 5 is a schematic side sectional view of this embodiment device, and FIG. 6 7 is an explanatory diagram showing the relationship between the irradiation field formed on the input surface of an image amplifier amplifier by a rectangular diaphragm and a circular input surface, FIG. 7 is an outline plan view of an example of a conventional polygonal diaphragm, and FIG. Figure 8 is a side view of its external appearance. 3...X-ray tube, 4...Hollow housing, 10...Rectangular aperture, 11...Vertical aperture piece, 11'...Horizontal aperture piece,
20...Circular aperture, 21...Drive disk, 22...
... Guide elongated hole, 23 ... Guide pin, 24 ... Swinging aperture piece, 25 ... Connecting pin, F ... Focus of X-ray tube.

Claims (1)

[Scope of utility model registration request] Consisting of a pair of rectangular aperture pieces made of X-ray opaque plate material that are movable toward and away from each other in a direction perpendicular to their respective longitudinal directions while maintaining a parallel relationship with each other in a parallel grid shape. It consists of a rectangular aperture, the rear end of which is rotatably supported around a single point, and an X-ray opaque plate material whose inner side near the tip is shaped into an arc shape or a curved shape that includes an arc. Composed of a combination of multiple swinging aperture pieces, the X-ray beam emitted from the X-ray tube
An X-ray diaphragm characterized in that a circular diaphragm having an aperture center on the center line of the ray beam and whose maximum circular aperture is larger than the maximum rectangular aperture of the rectangular diaphragm is arranged in parallel in the irradiation direction of the X-ray beam. Device.