Patent ID: 7736055

Claim:
An X-ray apparatus comprising an X-ray source and an X-ray detector, for which an exact relative arrangement with respect to one another is defined, and an associated subsystem for detection of any discrepancy between an instantaneous relative arrangement and the exact relative arrangement between the X-ray source and the X-ray detector; wherein the subsystem provides optical detection of any discrepancy from the exact relative arrangement, the subsystem including at least one light source, at least one light detector and at least one light reflector; and wherein the subsystem is configured in one of (a) a first configuration in which the at least one light reflector is arranged adjacent to the X-ray detector or its housing, and the at least one light source and the at least one light detector are arranged adjacent to the X-ray source or its housing or (b) a second configuration in which the at least one light reflector is arranged adjacent to the X-ray detector or its housing, and the at least one light source and the at least one light detector are arranged adjacent to the X-ray source or its housing.