X-ray imaging system including brightness control

The invention relates to an X-ray imaging system in which the exit screen of the X-ray image intensifier can be imaged, via a beam deflection element, on a pick-up device (CCD sensor) and on a photodiode for automatic dose control or exposure timing. Because the beam deflection element (prism, partly transparent cube or mirror) covers the entire cross-section of the exit screen, a uniformly illuminated exit screen is imaged on the pick-up device as a uniformly illuminated surface. When the pick-up device is arranged transversely of the prolongation of the X-ray image intensifier and the photodiode is arranged in the prolongation of the X-ray image intensifier, a compact system is obtained. When use is made of an anamorphic system comprising two prisms, a part of the light beam can be reflected to the photodiode from a surface of a prism. More accurate exposure timing can be achieved by measurement of the light reflected by the CCD sensors.