1. A method for reducing artifacts in an image, given a set of experimental projection data, wherein the following series of steps is performed one or more times: an edge-preserving blur filter step, in which a filter is applied to the current image such that artifacts or noise are reduced while preserving edges, wherein said filter calculates the new density of a pixel or voxel using information about nearby pixels or voxels; followed by a forward projection step, in which forward projection data are calculated from the filtered image from the previous step; followed by an updating step, wherein a new set of projection data is calculated as a function of the experimental projection data and the forward projection data, and this new set of projection data is used to reconstruct a new image.