X-ray system with a beam-gating diaphragm, and method for automatic adjustment thereof

A method for automatically adjusting a radiation diaphragm having a plurality of individually adjustable diaphragm elements, for subsequently obtaining a diagnostic radiation image, with a diagnostic radiation dose, of a subject, comprising the steps of:

• irradiating the subject with a radiation dose substantially lower than said diagnostic radiation dose passing through said diaphragm with said diaphragm elements open to generate a non-diagnostic localization exposure of the subject from radiation striking a radiation detector, having a detector surface in a detector plane comprised of a plurality of pixels, said exposures being composed of image points respectively formed by combining a plurality of adjacent pixels into a group;
• electronically, non-manually analyzing said localization exposure for determining only an exterior contour of the subject projected into said detector plane;
• and
• using said contour, automatically electronically calculating respective positions for the individual diaphragm elements at which the individual diaphragm elements substantially abut the exterior contour, and, before obtaining said diagnostic radiation image, automatically electronically moving the individual diaphragm elements to the respective calculated positions to substantially prevent direct irradiation of said radiation detector by radiation unattenuated by the subject when subsequently obtaining the diagnostic radiation image.