Iso-centering a volume of interest (VOI) (170) within a patient (168) to undergo examination on a rotational X-ray apparatus (100) is achieved by taking two differently-angled pictures (S210) and updating positional settings (172) for the patient's table (112) responsive to respectively displayed centering of the VOI (152). Alternatively, the operator identifies respective VOI centers (S410, S450) for each of the two displayed pictures, and corresponding table movement is automatically calculated (S420).