STEREO X-RAY INSTALLATION

An x-ray apparatus for generating an image of an examination subject, including an image pattern of an instrument, for the purpose of guiding the instrument, includes dual x-ray sources and a stereo viewer for generating a stereo image of the examination subject from a video signal produced by attenuation of the x-rays by the patient and the instrument, a detector which identifies the presence of the instrument in the video signal and generates an output signal upon detection thereof, a phase-locked loop circuit for generating an image pattern of the instrument from the output of the detector, a mixer which combines the image pattern with the video signal, and a switching stage connected between the output of the phase-locked loop circuit and the mixer, the switching stage having a control input supplied with the output signal from the detector such that the image pattern of the instrument is supplied to the mixer in the absence of an output signal from the detector.