Abstract: The exemplary disclosure includes a patient support, an x-ray tube with a diaphragm installation comprising diaphragm plates for the limitation of the x-ray beam irradiating the patient, and a cassette changer for x-ray film cassettes. The cassette changer is a large cassette changer for the entire area to be detected. The diaphragm installation exhibits a fixed diaphragm which limits the maximum size of the x-ray beam, and mechanism for the individual, independent adjustment of movable diaphragm plates determining the dimension of the x-ray beam in the longitudinal direction of the patient support.