An x-ray examination apparatus comprises an x-ray source and an x-ray detector. The x-ray detector includes a photoconductor to derive electric charges from incident x-radiation and read-out elements which derive electrical pixel-signals from the electric charges from the photoconductor. A central group of the read-out elements is located in a central region of the x-ray detector and a peripheral group of the read-out elements is located in a peripheral region which surrounds the central region. The x-ray examination apparatus being provided with a selection system to select the central group of read-out elements so as to supply pixel-signals from the central group of read-elements to the output circuit. The selection system may include an encompassing electrode to drain electric charges from the peripheral group. Or the selection system shields the peripheral group from x-rays.