A short scan uses only data from about 180.degree. gantry rotation instead of a full 360.degree. turn. In the provided short scan cardiac CT, a periodical axial focal spot movement is performed during gantry rotation, wherein the acquired data used for image reconstruction results from a 180.degree. rotation of the gantry. After the data acquisition, an approximate reconstruction is performed. In a preferred embodiment the focal spot moves on a short scan saddle trajectory.