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 Inveontrade small animal PET systems affords improved light collection and reduced number of photodetectors, while providing 67% greater axial field of view over the previous Focustrade system design. This is achieved using a tapered, multiple-element lightguide to couple the detector´s 1.6 mm pitch, 20 times 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 plusmn 0.26 (plusmn1 SD; range of 2.96 to 5.60), and the average detector energy resolution derived from individual crystal spectra was 12.3 plusmn 0.5% FWHM (plusmn1 SD; range of 11.2% to 13.9%). Application of this compact detector in conjunction with the Quicksilvertrade electronics architecture enables flexible system design for high performance PET imaging.