The invention relates to a data processor (1) for processing 3D radiographic imaging data. The processor comprises an input (2) for receiving the imaging data and for providing a motion signal indicative of a motion of the imaged subject. The processor comprises an image segmenter (4) for segmenting a body part of interest in a first image included in or derived from the imaging data, and a gating function calculator (5) for calculating temporal gating functions for voxels that belong to the body part taking the motion signal into account. The processor comprises an image reconstructor (3) for reconstructing the imaging data into reconstructed three-dimensional images, by taking the temporal gating functions into account such as to associate each of the reconstructed three-dimensional images with a corresponding phase of the motion.