Design and performance of a new pixelated-LSO/PSPMT gamma-ray detector for high resolution PET imaging

The gamma-ray detector developed for the Siemens Inveon (TM) small animal PET systems affords improved light collection and reduced number of photodetectors, while providing 67% greater axial field of view over the previous Focus (TM) System design. This is achieved using a tapered, multiple-element lightguide to couple the detector's 1.6 mm pitch, 20 x 20 LSO crystal array (32 mm square) to the 23.5 mm square photosensitive area of a Hamamatsu R8900 C12 PSPMT. The response of 900 production detectors to 511 keV photons has been analyzed. The average peak-to-valley ratio of crystal rows and columns derived from 2-d event position histograms was 4.08 +/- 0.26 (+/- 1 SD; range of 2.96 to 5.60), and the average detector energy resolution derived from individual crystal spectra was 12.3 +/- 0.5% FWHM (+/- 1 SD; range of 11.2% to 13.9%). Application of this compact detector in conjunction with the Quicksilver (TM) electronics architecture enables flexible system design for high performance PET imaging.