To position an imaging subject (16) in an imaging or therapy system (10), the imaging subject (16) is arranged on a linearly translatable tabletop (26) disposed on a movable trolley (30). A position of a region of interest (24) of the imaging subject along the linearly translatable tabletop is selected using an elongated position selector (40, 40′, 40″) that is elongated in a translation direction (z) of the linearly translatable tabletop (26). After the selecting, the movable trolley is docked with the imaging or therapy system (10). After the docking, the tabletop is linearly translated to move the imaging subject to the imaging or therapy system, the amount of linear translating being based on the selected position of a region of interest along the linearly translatable tabletop.
