A Full-FOV iterative algorithm applied to pixilated scintillation crystal

We present a mean square estimation (MSE) based algorithm for position calculation of a scintillation gamma cam­era dedicated to single photon imaging. The photodetector consist of a 2×2 array of Hamamatsu H8500C-Mod8 segmented-anodes PMT (10×10 cm detection area)coupled to an array of NaI(Tl) scintillation crystals with 1.8 mm pixel size. Phototubes are read out by a 256-independent channels electronics each reading simultaneously all the anodes of the MA-PMT. We analyzed position linearity and spatial resolution where the scintillation points are calculated both with MSE and with a standard center of gravity (CoG) algorithm, and with particular attention to the crystal edge and between tubes. The MSE algorithm improves the pixel identification and the linearity, and expands the useful field of view (UFOV) up to the whole detection area of the gamma cameras. In conclusion, MSE showing a greater advantage with respect to the CoG algorithm.