1. An imaging method for a multi-slice spiral CT scan, comprising: scanning an object to be examined with reference to its absorption behavior by a rotating ray bundle moving in the direction of the axis of rotation; collecting the measured absorption data; filtering the measured data to reconstruct a volumetric image from the measured data; and back-projecting the filtered data in three dimensions to generate a volumetric image of the object to be examined, the volumetric image representing absorption values obtained from the data of voxels, belonging to the volume of the object to be examined, for the radiation of the ray bundle, wherein the filtering is performed by multiple application of a ramp filter R {right arrow over (t)} and a masking operation M to a projection image in a different sequence.