JPH0256799B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an X-ray collimator.

In radiography (X-ray) of the head,
The patient is positioned with respect to the radiographic apparatus within a fixed axis of coordinates that can be rotated to allow imaging from different directions. Positioning of the patient is generally done relative to a straight line extending through the patient's ear cavity. If the patient is to be photographed from the side on, for example, 8 inch by 10 inch film, it is necessary to have a shutter that trims the head to ensure that the patient's chin and nose are photographed. The photograph is asymmetrical and perpendicular to the straight line passing through the ear cavity. On the other hand, when the photograph is taken from the front or the rear, the patient's head is usually positioned in the center of the photograph and the film is placed in a horizontal position. Therefore, when changing the photographing position, the position of the photographed area (target) relative to the collimator changes and the shutter is trimmed to a new shutter, i.e. the photograph on the film is trimmed to the same dimensions, but symmetrically about the photographed area. It is necessary to replace it with a shutter that can be trimmed so that it is positioned correctly.
For this reason, in conventional head imaging, a shutter plate suitable for each imaging is prepared in a separate carriage that moves over the runt for each different imaging, but this is complicated and takes time. was slowing down.

One solution to the above is disclosed in US Pat. No. 3,569,712. According to this, the size of the fixed collimator opening is adjusted by shuttering from one edge by means of a sliding plate. By rotating this plate around the collimator body, the collimator aperture can be shuttered from any angle. This solution takes up a lot of space and
This results in exposing the patient to an unnecessary amount of radiation. That is, the shuttering is done only from one edge,
Another reason is that the collimator aperture must have a sufficient size to cover the entire radiographic region.

U.S. Pat. No. 3,849,649 shows a collimator in which the size of the collimator aperture can be reduced by rotating a separate shutter element through 90 degrees. This shutter element has an aperture of the same size as the collimator aperture. Since the aperture of this collimator is always positioned symmetrically with respect to the collimator body, it is not effective if the position of the region to be imaged shifts with respect to the collimator.

It is an object of the present invention to provide a novel collimator device which eliminates the drawbacks of the prior art mentioned above and which can be adjusted to various positions required depending on the area to be imaged.

A collimator device according to the present invention includes a collimator body provided with a shutter element having an opening that restricts the X-rays to converge to a convergent X-ray of a desired size and shape. provided in the transverse plane of the body so as to be rotatable about its axis;
In addition, the center of the opening, which is eccentrically provided with respect to the collimator body and restricts X-rays, is rotatable so that it can be shifted onto or away from the axis of symmetry of the collimator body.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the accompanying drawings, reference numeral 1 designates a collimator body, which body has a support element 2 journalled thereon. Reference numeral 3 designates a shutter element to which a shutter plate 6 having an opening 7 transparent to X-rays is attached by means of a member 8.
If the target (area) to be imaged requires the use of an aperture of a different size or shape, the shutter plate 6 can be replaced with a new one as necessary. On the other hand, one of certain shape and dimensions
If photography is possible with one aperture, the aperture 7 is formed in the shutter element 3 and a separate shutter plate 6 is not required. The center of opening 7 is P ₁
It is shown.

The shutter element 3 is supported on the support element 2 by a support pin 4. The shutter element 3 also has control means (levers) 5 extending beyond the body 1 and by means of which a displacement of the shutter element 3 relative to the body 1 is effected. The support element 2 is provided with a guide edge 9, which determines the degree of freedom of rotation of the shutter element 3 about the pin 4. On the other hand, the guide edge 9 and the control means 5 are also used to effect a rotation of the support element 2 and the shutter element 3 relative to the center line P ₂ of the body 1. The collimator is also provided with a movable lid 10 containing an aperture transparent to X-rays.

In the embodiment shown in FIGS. 1 to 4, the support element 2 is journalled in the inner jacket part of the body 1. In the embodiment shown in FIGS. Since the body 1 is fixed, its jacket must be provided with slot-like openings (not shown) that allow all necessary displacements of the control means 5 of the shutter element 3. On the other hand, in the embodiment shown in FIGS. 5 and 6, the support element 2 is journalled around the body 1. In the embodiment shown in FIGS. The guide edge 9 therefore directly determines the size of the opening required by the control means 5.

Since the operation of the collimators according to the two embodiments described above is similar, only the operation of the collimators shown in FIGS. 1-4 will be described.

In FIG. 1, the aperture 7 is in a vertical position;
It is arranged asymmetrically with respect to the central axis _P2 of the main body 1. Therefore, in head radiography, this state of the collimator is used when photographing the head from the side. When photographing the head from the front or back, perform the following steps: The control means 5 is displaced from one guide edge 9 to the other guide edge 9 (FIG. 3), and this other guide edge 9 is moved so that the center P ₁ of the opening 7 is aligned with the main body 1.
Move it until it is aligned with the central axis _P2 of That is, the control means 5 rotate the support member 2 until the opening 7 is in its horizontal position. By doing so, the area to be photographed becomes symmetrical with respect to the opening 7 and the central axis _P2 of the main body.
On the other hand, in order to change from a state where the head is photographed from the front or back to a state where the head is photographed from the side, the operation opposite to the above is performed.

As a variant of the embodiment described above, the body 1 itself can also be rotated to change the aperture 7 from vertical to horizontal or vice versa, in which case the body 1 is attached to an X-ray generator or Must be journalled in the member.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a collimator according to the present invention;
Figure 2 is a - diagram of Figure 1; Figures 3 and 4.
FIG. 5 is a diagram showing a collimator according to another embodiment; FIG. 6 is a diagram showing the collimator of FIG. 5 in different operating positions; FIG.

Claims (1)

[Scope of Claims] 1. In an X-ray collimator used for head X-ray photography, a cylindrical collimator body connected to an X-ray generator and used to concentrate X-rays. It comprises a collimator body 1 provided with a shutter element 3 having an aperture 7 for confining the converging X-rays, characterized in that the transverse cross section of the same body is arranged such that the shutter element 3 can rotate about the axis of symmetry of the collimator body 1. Rotation such that the center _P1 of the aperture, which is provided in a plane and eccentrically relative to the collimator body and restricts the X-rays, can be shifted onto or away from the axis of symmetry _P2 of the collimator body. An X-ray collimator that can be used to 2. The collimator body 1 has a support element 2 provided therein, which element has a pin 4 provided in an eccentric position for supporting the shutter element 3 so as to be able to rotate as described above. A collimator according to claim 1. 3 said shutter element 3 has control means 5 extending externally beyond said collimator body for effecting a displacement of said element;
Patent, in which the support element 2 has a guide edge 9, which edge is adapted to determine the amount of rotation of the shutter element 3 relative to the support element 2, and in which the rotation of the support element takes place via this guide edge. A collimator according to claim 2. 4. A collimator according to claim 3, wherein the support element 2 is arranged inside the collimator body 1 and is rotatably supported by an internal jacket surface of the body. 5. Collimator according to claim 3, in which the support element 2 has a jacket part extending at least partially over the circumferential surface of the collimator body 1. 6 Means 8 for the shutter element 3 to interchangeably support shutter plates 6 of various openings;
A collimator according to any one of claims 1 to 5, comprising: