X-RAY EXAMINATION APPARATUS INCLUDING A CONTROL LOOP FOR ADJUSTING THE X-RAY FLUX

摘要

An X-ray examination apparatus comprises an X-ray source (1) for emitting an X-ray beam, an X-ray detector (6) for detecting an X-ray image and converting it into an optical image and a video extractor (8) which is coupled to the X-ray detector (6) via an optical coupling means (9). The optical coupling means (9) is provided with an optical pick up (11) for feeding a fraction of the lightflux to a photosensor (12) which produces a control signal for adjusting the X-ray flux from the X-ray source (1). The photosensor (6) is provided with an array of pixels, with weighting means for the signals detected in or by each of said pixels, and with means to determine a mean value of the detected and weighted signals, yielding a control signal which is fed back in order to adjust the X-ray flux from the X-ray source (1).