I. K. Hong S. T. Chung H. K. Kim Y. B. Kim Y. D. Son Z. H. Cho Ultra Fast Symmetry and SIMD-Based Projection-Backprojection (SSP) Algorithm for 3-D PET Image Reconstruction. 789-803 2007 26 IEEE Trans. Med. Imaging 6 http://doi.ieeecomputersociety.org/10.1109/TMI.2007.892644 db/journals/tmi/tmi26.html#HongCKKSC07