A radiation detector, in particular an X-ray radiation detector, in the form of a flat-panel detector, may comprise a scintillator layer applied to a substrate and comprising elongated needles made from a scintillator material forming the scintillator layer, and an actively readable pixel array composed of photodiodes, wherein the thickness of the scintillator layer may be in the range of 900 μm-2500 μm, and wherein the angle at which the needles stand relative to the pixel array, starting from 90° in the center of the detector, may decrease with increasing distance from the center of the detector.