A new iterative algorithm for pixilated and continuous scintillating crystal

Abstract In this work, we present a mean square estimation (MSE) based algorithm to calculate the position of a scintillation event within the crystal of a gamma camera dedicated to single photon imaging applications. The performances analysis takes into account pixilated and continuous shape configuration crystals, coupled to an Hamamatsu H8500C multi-anodes PMT (MA-PMT). The readout electronics used for readout has 64-independent channels each reading simultaneously the 64 anodes of the MA-PMT. An array of NaI(Tl) scintillation crystal with 2.0 mm pitch, one of CsI(Tl) with 1.6 mm pitch and one of YAP with 2.0 mm pixel size are taken into account. In addition, a continuous LaBr 3 (Ce) crystal coupled to an Hamamatsu H8500C-Mod8 MA-PMT equipped with a super-bialkali photocathode (38% QE at 380 nm) was analyzed. Position linearity and spatial resolution analyzed with collimated (for continuous crystal) and uncollimated (for pixilated crystal) Co 57 radioactive source and the scintillation points are calculated both with MSE and with a standard center of gravity (CoG) algorithm. The MSE algorithm improves spatial resolution and expands the useful field of view (UFOV) of the gamma camera that nearly reaches the size of the photocathode area thus showing a great advantage with respect to the CoG algorithm.