1. An examination apparatus for examination of an object of interest, the examination apparatus comprising: a radiation source that rotates on a scan path about an axis of rotation around the object of interest and that emits electromagnetic radiation to the object of interest; a detector unit that detects image data from the object of interest; and a reconstruction unit that reconstructs the image data on the basis of an approximate reconstruction procedure, wherein the approximate reconstruction procedure comprises a fan-beam to parallel beam rebinning, a pre-weighting, a one-dimensional filtering, and a three-dimensional back-projection; wherein the examination apparatus performs a periodical movement of a focal spot of the emitted electromagnetic radiation in a direction along the axis of rotation during the movement of the radiation source; and wherein the focal spot moves on a short scan saddle trajectory resulting from a short scan interval λ short =[λ 0 ,λ 0 +π+γ], with an arbitrary start angle λ 0 and a fan angle of γ.