A method of processing a radiographic image obtained with a slot-scanning radiographic system to compensate for scattering of the illuminating beam in the tissue being imaged. A conventional circularly symmetric scatter mask, for example a point spread function, is adjusted to take account of the shape of the detector and time delay integration used in the slot scanning system, the presence of an air gap between the detector and the bottom of the tissue being imaged, and the collimation of the radiation beam. The result is a sharpened and shortened point spread function.