Patent Number: 054066115
Section: summary

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a radiation gating device, of the type suitable for use in an x-ray diagnostics installation. 2. Description of the Prior Art German OS 1 441 312 discloses a gating device for an X-ray diagnostics installation which has two diaphragm plate pairs that are arranged offset by 90.degree. relative to one another in parallel planes. The diaphragm plate pairs can be adjusted in opposite directions via their mounts, which are attached at the end-faces of the diaphragm plates. The Siemens book "Bildgebende Systeme fuer die medizinische Diagnostik", edited by Erich Krestel, published by Siemens A. G., Berlin and Munich, 1980, pages 334 and 335, FIGS. 8.49 and 8.50 shows the beam path of a radiation apparatus in the form of a computer tomograph. The beam of the X-ray radiator is thereby gated to form a fan beam by a focus-proximate gating device and a gating device arranged in front of the arcuate radiation receiver composed of individual detectors. To that end, diaphragm plates arranged lying opposite one another form a slot-shaped opening that is variable via adjustment means. The adjustment of the diaphragm plate ensues in a direction perpendicular to its longitudinal axis, for which appropriate mounts and guides are provided. These mounts and guides are arranged at the end faces of the diaphragm plate aligned perpendicularly relative to the longitudinal axis of the diaphragm plate, so that a large structural width of the gating device is achieved. In order to accomplish the adjustment of the diaphragm plates, the adjustment means must be attached in the adjustment direction of the diaphragm plate, which results in a large structural width of the gating device and a mechanically complicated structure. SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation gating device having a compact structure and simple design, and which enables a precise adjustment of the diaphragm plate in the beam path. This object is achieved in a radiation gating device constructed in accordance with the principles of the present invention having at least one diaphragm plate adjustable in the beam path of a radiation transmitter, with at least one guide aligned obliquely relative to the longitudinal axis of the diaphragm plate is provided at the diaphragm plate, and adjustment means attached to the diaphragm plate so that the diaphragm plate is adjustable in the beam path in a manner defined by the guide. An advantage of the invention is that the adjustment means can be attached either along the longitudinal axis of the diaphragm plate or perpendicularly relative thereto, as a consequence of the guide extending obliquely relative to the longitudinal axis of the diaphragm plate, as a result of which the adjustment in the beam path can be effected. Only a single guide has to be provided for guiding the diaphragm plate, so that the structural outlay is low. The compact structure of the gating device derives in that the guide is provided at the diaphragm plate and not, as in the prior art, outside the edge region of the diaphragm plate. A structure that is not complicated is achieved in an embodiment wherein the adjustment means if a motor-adjustable spindle that attached to the diaphragm plate via an articulation for the adjustment of the diaphragm plate. In an embodiment which is uncomplicated in terms of fabrication technology, the guide is implemented as a recess provided in the diaphragm lamella into which, a pin, provided at the gating device housing, extends. In an embodiment which is advantageous for obtaining a fan-shaped ray beam, two diaphragm plates are arranged opposite one another and form a slot-shaped opening for gating the beam of the radiation transmitter, and the diaphragm plates are adjustable at their guide arranged obliquely relative to the longitudinal axis of the diaphragm plates, so that the spacing of the diaphragm plates from one another can be increased or diminished. Such a gating device can be especially advantageously utilized in a computer tomography apparatus when the gating device is arranged preceding the radiation receiver in the radiation direction. An economical format of the gating device thereby results because only a single adjustment means need be provided even if a plurality of diaphragm plates are arcuately joined to one another, with the adjustment means attached along the longitudinal axis of each diaphragm plate.