A device for the sensitive detection of X-rays comprises a structured scintillator screen optically coupled to a semiconductor image sensor. The scintillator screen comprises individual columnar elements covered with material showing high optical reflection. Each columnar element represents a pixel, and light flashes created by an X-ray photon in a scintillating event exit through a short surface of the columnar element for detection with a semiconductor image sensor. The semiconductor image sensor comprises a multitude of photosensor elements, and one or more of these photosensor elements receives light from a scintillator screen pixel. Each photosensor element of the image sensor comprises a semiconductor volume where photocharge is created, a lateral drift-field device for the collection of photocharge, an electronic detection circuit for the conversion of collected photocharge packets either into proportional voltage pulses, into binary signals indicating the arrival of X-ray photons or into digital signals whose values correspond to the energy of the incident X-ray photons.