An imaging apparatus comprising a radiation source (2) for emitting radiation from a focal region (20) through an imaging area (5), a detection unit (6) for detecting radiation from said imaging area (5), said detection unit comprising an anti-scatter grid (62) and a detector (61), a gantry (1) to which said radiation source (2) and said detection unit (6) are mounted and a controller (9) for controlling said detection unit (6) to detect radiation at a plurality of projection positions and for manipulating the position, setting and/or orientation of at least a part of said radiation source (2) and/or said detection unit (6) at first projection positions (80) so that the radiation incident on the detector (61) at said first projection positions is attenuated by said anti-scatter grid (62) to a larger extent compared to second projection positions (80) representing the remaining projection positions.
