Characteristics of a pair of small field-of-view LSO scintillation cameras

The authors created two miniature scintillation cameras by coupling identical, thin LSO crystals to position sensitive photomultiplier tubes (PSPMTs). The performance of these cameras was established in both single photon and coincidence imaging modes and in relation to similar gamma cameras equipped with NaI(Tl) crystals. The intrinsic spatial resolution of the LSO cameras was 2.3 mm at 140 keV and 1.2 mm at 511 keV. The coincidence time resolution was 3 ns with an energy resolution of 16.5% at 511 keV. With no sources present, an intrinsic event rate of 300/sec/cm/sup 3/ of LSO from /sup 176/Lu was observed. Although this background count rate may be a limitation in some applications, LSO PSPMT scintillation cameras offer several important performance advantages over similar NaI(Tl) and BGO cameras that include improved count rate performance, coincidence timing, stopping power relative to NaI, and energy resolution relative to BGO.