A method for generating a four-dimensional representation of a periodically moving target region is proposed. A motion-compensated three-dimensional image dataset is determined from two-dimensional projection images recorded from different projection directions. Estimation parameters that describe a non-periodic motion and are derived from a motion model formulated independently of the phase of the periodic motion with respect to the recording instants of the projection images are determined from the projection images, such that the three-dimensional image dataset represents a static reconstruction based on all projection images for a specific instant. The three-dimensional image dataset is animated from the estimation parameters used in its reconstruction. The motion information that is missing in the estimation parameters due to the two-dimensionality of the projection images is additionally determined using a boundary condition that describes the periodicity of the motion, and used for the animation.