Reconstruction of factor structures using discrete tomography method

Our aim was to estimate the volumes of homogeneous structures whose contrast / intensity was changing with time, using only few (here 4) projections of the structures. Each projection was recorded over a period of time and consisted of a sequence of images. The projections of the structures were first separated by factor analysis of the total projections. Then each structure was reconstructed individually from its factor projections using discrete tomography. Assumed application is the single-photon emission computed tomography (SPECT).