JPH0621040Y2 - X-ray movable diaphragm device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] This invention is an X-ray deciding device for determining an X-ray irradiation field in an X-ray imaging apparatus in which fluoroscopy by X-ray and film photographing can be switched freely.
The present invention relates to a line movable diaphragm device.

[Conventional technology]

Generally, in an X-ray imaging apparatus, an opening amount of diaphragm blades is set corresponding to a transparent area on a subject, X-rays are viewed through the X-ray, and this is monitored via an image intensifier and an optical system. On the other hand, in the case of magnifying the fluoroscopic region during fluoroscopy, a film is placed in place of the image intensifier for radiography. At this time, even if the position of the image intensifier at the time of see-through and the position of the film at the time of shooting are different, film shooting is performed without changing the irradiation field on the light receiving surface. The X-ray movable diaphragm device in such an X-ray imaging apparatus compares the signal giving the size of the irradiation field with the signal from the potentiometer with which the diaphragm blade drive motor is interlocked, and the difference between the two signals is zero. The aperture blade drive motor is controlled so that the change in the distance between the X-ray irradiation focus and the light receiving surface is detected as a signal. The size is controlled so that it is always constant on the light receiving surface.

[Problems to be solved by the invention]

By the way, in the conventional X-ray movable diaphragm device, as shown in FIG. 2, the X-ray irradiation field A on the light-receiving surface of the image intensifier I during fluoroscopy is X-ray on the surface of the film F during film photographing. If it is maintained to be the same as the radiation field A ′, the fluoroscopic region of the subject B is narrowed, and the entire fluoroscopic region of the subject B cannot be magnified during fluoroscopy. This is because, during film photography, the X-ray movable diaphragm C, the subject B, and
When the distance from the X-ray irradiation focus O becomes large in the order of the light-receiving surface of the image intensifier I and the light-receiving surface of the film F, the X-ray movable diaphragm C is narrowed and the light-receiving surface of the image intensifier I is changed. This is because the apex angle θ ₂ of the irradiated X-ray cone with respect to the X-ray irradiation field on the light receiving surface of the film is smaller than the apex angle θ ₁ of the irradiated X-ray cone with respect to the X-ray irradiation field.

By the way, in X-ray fluoroscopy, there may be a clinical request that the fluoroscopic region on the subject, which is narrowed down by the X-ray movable diaphragm during fluoroscopy, be directly filmed. However, the above-mentioned conventional X-ray movable diaphragm device cannot meet such a demand.

The present invention has been made in view of the above points, and an object thereof is to provide an X-ray movable diaphragm device capable of magnifying an image on a film surface while leaving the fluoroscopic region on a subject under fluoroscopy as it is.

[Means for solving problems]

In order to solve the above technical problems, this invention has a movable diaphragm device having the following configuration. That is, an irradiation field size signal giving means for selectively giving a signal giving the size of the irradiation field at the time of fluoroscopy and at the time of photographing, diaphragm blades whose opening surface is narrowed according to the size of the irradiation field, A diaphragm blade driving motor for driving the diaphragm blade, a potentiometer linked to the diaphragm blade driving motor, a comparing means for comparing both the signal from the potentiometer and the signal from the irradiation field size signal providing means, and this comparison. A motor control means for controlling the diaphragm blade drive motor so that the comparison value in the means becomes zero, and the size of the irradiation field on the light-receiving surface during fluoroscopy and the light-receiving surface during fluoroscopy with respect to the X-ray irradiation focus. In the X-ray movable diaphragm device for determining the size of the irradiation field on the film light receiving surface placed at a distance, the setting is made by the signal from the irradiation field size signal giving means. In addition to the apex angle maintaining means for fixing the opening angle of the aperture blades during the fluoroscopy to keep the irradiation X-ray cone apex angle constant, at the time of photographing by the aperture amount of the aperture blades fixed by the apex angle maintaining means. When the size of the irradiation field exceeds the film size, the X-ray movable diaphragm device is provided with an excess suppressing unit that narrows diaphragm blades so that the size of the irradiation field at the time of photographing matches the film size. It is a summary.

[Action]

With the X-ray movable diaphragm device of the present invention having the above-described structure, when an attempt is made to film an image of the see-through region after see-through,
The apex angle maintaining means can fix the opening amount of the diaphragm blade during the fluoroscopy to maintain the irradiation X-ray cone apex angle constant. Therefore, the distance between the X-ray irradiation focal point and the film position is made larger than the distance between the X-ray irradiation focal point and the light receiving surface during fluoroscopy, but the X-ray irradiation area on the subject is kept the same. Thus, it becomes possible to take an enlarged image of the entire fluoroscopic region.

On the other hand, as a result of the irradiation X-ray pyramidal angle being kept constant during filming, the size of the irradiation field at the film position may exceed the film size. In this case, as a safety measure, the excess suppressing means narrows the diaphragm blades so that the size of the irradiation field at the time of photographing matches the film size.

〔Example〕

An embodiment of the X-ray movable diaphragm device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the construction of an X-ray movable diaphragm device according to an embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes an aperture blade opening / closing handle, which is a distance-corrected image intensifier size signal.
11 is connected to one terminal a of the changeover switch 12. Reference numeral 13 is a distance-corrected film size signal, which is connected so as to be sent to the other terminal b of the changeover switch 12 and one input terminal of the excess suppression comparator 14. Reference numeral 15 is a diaphragm control comparator, and an image intensifier size signal 11 or film size signal 13 from the common terminal of the changeover switch 12 to one of its input terminals.
Is entered. Reference numeral 16 is a diaphragm fixing relay switch, which is normally provided between the output side of the diaphragm controlling comparator 15 and the base side terminal of the motor driving transistor 17 in a closed state. Reference numeral 18 denotes a diaphragm blade drive motor, which includes a common terminal of the changeover switch 12 and a motor drive transistor 17
It is designed to be driven through a circuit connected to the emitter side of. Reference numeral 19 is a potentiometer, which is connected to the diaphragm blade drive motor 18, and the value of the potentiometer 19 is connected to the other input terminal of the diaphragm control comparator 15 and the other input terminal of the excess suppression comparator 14. Has been done.
The output terminal of the excess suppression comparator 14 is connected to a relay (not shown) for closing the diaphragm fixing relay switch 16.

Next, the operation of the embodiment apparatus configured as described above will be described. First, by connecting the change-over switch 12 to the terminal a side during fluoroscopy, the distance-corrected signal of the maximum irradiation field size is transmitted through the diaphragm blade opening / closing handle 10 to one input terminal of the diaphragm control comparator 15. Reach Further, a signal indicating the actual irradiation field size on the light receiving surface of the image intensifier reaches from the potentiometer 19 connected to the diaphragm blade driving motor 18 to the other input terminal of the diaphragm control comparator 15. Then, the maximum irradiation field size signal and the signal indicating the irradiation field size on the light receiving surface of the image intensifier are electrically compared by the diaphragm control comparator 15, and the diaphragm blades are arranged so that the latter coincides with the former. The drive motor 18 drives the diaphragm blades.

Next, when filming the transparent region as it is, the aperture fixing relay switch 16 is opened and the changeover switch 12 is changed over to the other terminal b by an operation from the operation panel (not shown) of the apparatus. As a result, the diaphragm blade drive motor 18 is stopped and the opening amount of the diaphragm blade is fixed, so that the irradiation X-ray pyramidal angle becomes constant. Therefore, even when the distance between the X-ray irradiation focal point and each light receiving surface during fluoroscopy and radiography is different, film radiography can be performed in the fluoroscopic region on the subject.

On the other hand, since the distance between the X-ray irradiation focal point and the light-receiving surface is increased by keeping the aperture amount of the diaphragm blade constant, the size of the X-ray irradiation field on the film surface at the time of photographing becomes smaller than the film size. It may exceed. In such a case, the signal from the potentiometer 19 indicating the size of the X-ray irradiation field on the light receiving surface of the film and the size signal 13 of the film to be used are electrically compared in the excess suppression comparator 14, and the former is When the latter is exceeded, the aperture fixing relay switch 16 is closed, driving of the aperture blades is restarted, and control is performed so that the former and the latter match.

〔effect〕

According to the X-ray movable diaphragm apparatus according to the present invention described above, when it is desired to image the fluoroscopic region on the subject as it is,
By fixing the aperture of the diaphragm blade as it is when seeing through,
This becomes possible, and it is possible to solve the problem that the imaging is performed in which a part of the see-through region is missing, which has occurred in the past. On the other hand, it is expected that the size of the X-ray irradiation field at the time of shooting will exceed the film size by fixing the aperture of the diaphragm blades as it is during fluoroscopy. It is safe because the size of is matched to the film size.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of an X-ray movable diaphragm device according to the present invention, and FIG. 2 is each fluoroscopic region, X-ray irradiation field and irradiation during fluoroscopy and photographing by a conventional X-ray movable diaphragm device. It is a figure which shows the change of an X-ray frustum angle. 10 …… Aperture blade opening / closing handle, 11 …… Image intensifier size signal, 12 …… Changeover switch, 13 …… Film size signal, 14 …… Excessive suppression comparator, 15 …… Aperture control comparator, 16 ...... Aperture fixing relay switch, 17 ...... Motor drive transistor, 18 ...... Aperture blade drive motor, 19 ...... Potentiometer.

Claims (1)

[Scope of utility model registration request] 1. An irradiation field size signal giving means for selectively giving a signal giving a size of an irradiation field at the time of fluoroscopy and at the time of photographing, and an aperture blade whose opening surface is narrowed according to the size of the irradiation field. And a diaphragm blade drive motor for driving the diaphragm blade, a potentiometer linked to the diaphragm blade drive motor, and a comparison means for comparing both the signal from the potentiometer and the signal from the irradiation field size signal giving means. And a motor control means for controlling the diaphragm blade drive motor so that the comparison value in the comparison means becomes zero, and the size of the irradiation field on the light receiving surface at the time of see-through and the X-ray irradiation focus at the time of see-through. In the X-ray movable diaphragm device for determining the size of each irradiation field on the light receiving surface of the film placed farther from the light receiving surface, a signal from the irradiation field size signal giving means is used. An apex angle maintaining means for fixing a fixed opening amount of the diaphragm blades during fluoroscopy to keep the irradiation X-ray cone apex angle constant is provided, and imaging is performed by the opening amount of the diaphragm blades fixed by the apex angle maintaining means. When the size of the irradiation field at the time exceeds the film size, the X-ray movable diaphragm is provided with excess suppression means for narrowing the diaphragm blades so that the size of the irradiation field at the time of photographing matches the film size. apparatus.