Lin Zhou Kathleen Vunckx Johan Nuyts Multi-Pinhole SPECT Calibration: Influence of Data Noise and Systematic Orbit Deviations. 1795-1807 2011 30 IEEE Trans. Med. Imaging 10 http://dx.doi.org/10.1109/TMI.2011.2148123 db/journals/tmi/tmi30.html#ZhouVN11