Experimental evaluation of mixed lutetium-based scintillators for nuclear medicine detectors

Abstract Lutetium Fine Silicate (LFS-3) scintillation crystals were experimentally evaluated for their potential application in nuclear medicine imaging detectors. A series of 3 × 3 mm 2 Lutetium Fine Silicate (LFS-3) crystals with thicknesses ranging from 4 to 20 mm were coupled to a PM3350-EB silicon photomultiplier and exposed to a 662 keV Cs-137 γ-ray source. Key detector performance metrics—energy resolution, photofraction, and sensitivity were extracted from the energy spectra data aquired. The best energy resolution was achieved with the 5 mm crystal (11.41%), while the highest photofraction (11.04%) was observed for the 6 mm sample. Sensitivity increased with thickness, reaching 0.27% for the 20 mm crystal. For reference, two Lutetium Yttrium Oxyorthosilicate (LYSO:Ce) crystals were also tested under identical conditions. While the 2 × 2 × 10 mm 3 LYSO crystal yielded an energy resolution of 10.35%, the 5 × 5 × 5 mm 3 sample showed degraded resolution (17.07%) despite higher photofraction and sensitivity. These results demonstrate that LFS-3 crystals offer a competitive balance of performance characteristics and may represent a promising alternative for clinical implementation in PET and hybrid PET/MRI systems.