A method is disclosed for positioning a body region of interest of a patient in the isocentre of the imaging system of a computer tomograph or C-arm device. The method involves using the computer tomograph or C-arm device to record a topogram of the patient, determining a distance between the body region of interest and the isocentre from the topogram, and shifting a patient positioning device or the imaging system by this distance in order to move the body part into the isocentre. In the proposed method, the topogram is recorded in sections from various directions that are perpendicular to one another. The method enables the body region of interest to be positioned without the use of any external aids.