In a method for mathematical compensation of a periodic movement of an organ in a first image-generation method used to image said organ, two time series of three-dimensional image data are acquired using gating, one by the first image-generation method and one by the second image-generation method, the image data that have been acquired by the second image-generation method being used to calculate motion fields which are applied for the compensation of the data from the time series which was acquired by the first image-generation method. The compensation encompasses the mathematical inclusion of motion fields and the mapping of the image data to a reference time. All the image data mapped back to the reference time are added together.