A method for improved utilization of a radiation dose applied to an examination object 8 during topogram scanning of a CT system 1, and a CT system with a system axis using a cylindrical curved multi-row detector 3, are disclosed. In an embodiment, the method includes topogram scanning of the examination object with at least one emitter-detector combination 2, 3 disposed on a rotatable gantry from a predetermined rotation angle of the gantry, wherein during the topogram scanning a relative movement occurs between examination object and emitter-detector combination in the system axis direction; calculation of at least one flat image in at least two planes running in parallel to the system axis 7 in each case by a tomosynthesis reconstruction; and storage and/or further processing of at least one of the flat images of the examination object to represent a topogram.