Abstract: Absorption filters are positioned in an x-ray examination apparatus according to the invention by adjusting them on the basis of the posture of the carrier supporting the x-ray source and the x-ray detector. To that end adjustment curves relating carder posture to filter adjustment are employed. The posture of the carder determines the orientation of the x-ray beam path. Because there are relatively few anatomical differences among patients to be examined, the adjustment of absorption filters on the basis of the beam orientation is quite adequate. Further improvement is achieved by providing sets of adjustment curves, each set pertaining to a class of patients, such as e.g. corpulent or slender patients, or infants or adults.

Abstract: An X-ray examination apparatus incorporating digital image subtraction in which from a series of images to be formed of an object with and without contrast medium those images are selected for subtraction which result in ultimate images which combine a low motional unsharpness with adequate contrast. Images are also formed on at least one of the edges of the contrast bolus, so that in each position several contrast images can be formed with a single contrast bolus.