Abstract: A parallel processing architecture and method, based on the 3D Algebra Reconstruction Technique (ART), for iteratively reconstructing from cone beam projection data a 3D voxel data set V representing an image of an object. The cone beam projection data is acquired by employing a cone beam x-ray source and a two-dimensional array detector to scan the object along a source scanning trajectory to obtain, at each of a plurality of discrete source positions .theta..sub.i on the source scanning trajectory, a 2D measured cone beam pixel data set P.sub.i. The 3D voxel data set V is subdivided into or organized as a plurality m of independent voxel subcubes V.sup.0 through V.sup.m-1 each containing a plurality of voxels. As a result of the subdivision of the 3D voxel data set V into voxel subcubes, the 2D measured cone beam pixel data set P.sub.i (measured projection data array) is correspondingly subdivided for each source position .theta..sub.