Method of and software for conducting motion correction in tomographic scanning and system for tomographic scanning using the method

During data acquisition in a tomographic scan of a subject unscattered events and scatter events are collected. The data are corrected for the scatter events and movement of the subject during the scan. A scatter estimate is derived for use in the reconstruction of an image of the subject; a first step in the derivation has a first dependence on the movement of the subject. The image of the subject is derived from the detected events using the scatter estimate; a second step in this derivation has a second dependence on the movement of the subject, the dependence being different from that of the first step.