An X-ray image sensor, comprising an X-ray converter layer for converting X-rays into signals received by a semiconductor detector for sampling and detecting converted X-rays as electrical signals, and a connection substrate comprising electrical connections, the X-ray converter layer bonded to a first surface of the semiconductor detector and the connection substrate arranged at a second surface of the semiconductor detector, opposite the X-ray converter layer, wherein the semiconductor detector in at least one edge portion comprises vias for through-contacting detector elements formed in or on the first surface of the semiconductor detector to the connections substrate.