Patent ID: 7573980

Claim:
A method for operating an X-ray computer tomograph including a rotatable measuring system which includes a first X-ray source having a downstream diaphragm and a first matrix detector in an opposite arrangement with respect to an axis of rotation, wherein the first matrix detector is a flat panel image detector, comprising: moving, in a selectable first mode of operation for producing sectional images, a patient accommodated on a couch relative to the measuring system in the z-direction, irradiating an area to be examined in circulating fashion by rotating the measuring system, and detecting the X-ray radiation emerging from the area to be examined using the first matrix detector; not moving, in a selectable second mode of operation for producing angiographical images, the patient accommodated on the couch relative to the measuring system in the z-direction, irradiating the entire area to be examined at a first angle of rotation of the measuring system by opening said diaphragm to an extent that an irradiated X-ray beam hits the first matrix detector over the entire area to be examined, and detecting the X-ray radiation emerging from the area to be examined isochronously using the first matrix detector; and moving, in a selectable third mode of operation for producing topographical overview images, the patient accommodated on the couch relative to the measuring system in the z-direction, irradiating an area to be examined, detecting the x-ray radiation emerging from the area to be examined using the first matrix detector at a third angle of rotation, and using the detected x-ray radiation to produce the topographical overview image.