Article

Properties of LYSO and recent LSO scintillators for phoswich PET detectors

Dept. of Nucl. Med. & Radiobiol., Univ. de Sherbrooke, Que., Canada
IEEE Transactions on Nuclear Science (Impact Factor: 1.46). 07/2004; DOI: 10.1109/TNS.2004.829781
Source: IEEE Xplore

ABSTRACT The luminescence and nuclear spectroscopic properties of the new cerium-doped rare-earth scintillator lutetium-yttrium oxyorthosilicate (Lu0.6Y1.4Si0.5:Ce, LYSO) were investigated and compared to those of both recent and older LSO crystals. UV-excited luminescent spectra outline important similarities between LYSO and LSO scintillators. The two distinct Ce1 and Ce2 luminescence mechanisms previously identified in LSO are also present in LYSO scintillators. The energy and timing resolutions were measured using avalanche photodiode (APD) and photomultiplier tube (PMT) readouts. The dependence of energy resolution on gamma-ray energy was also assessed to unveil the crystal intrinsic resolution parameters. In spite of significant progress in light output and luminescence properties, the energy resolution of these scintillators appears to still suffer from an excess variance in the number of scintillation photons. Pulse-shape discrimination between LYSO and LSO scintillators has been successfully achieved in phoswich assemblies, confirming LYSO, with a sufficient amount of yttrium to modify the decay time, to be a potential candidate for depth-of-interaction determination in multicrystal PET detectors.

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    • "atomic number, density, light yield), the light propagation inside crystals impacts a number of performance parameters including energy resolution and time resolution (Cherry et al 1995, Huber et al 1999, Moses and Derenzo 1999, Moses and Ullisch 2006, Peng and Levin 2010). In particular, surface treatment and reflectors affect the processes of both reflection and refraction of light photons at internal interfaces, and consequently impact the efficiency of light collection (Barton et al 1999, Saoudi et al Q2 2000, Pepin et al 2004, Heinrichs et al 2002, Dhanasopon et al 2005, Vandenbroucke and Levin 2008, Janecek and Moses 2010). Moreover, different light transport processes also result in different temporal responses and time resolution, which is critical for a time of-flight (ToF) PET when using fast scintillation crystal materials and novel photodetector technologies (Moses and Ullisch 2006, Spanoudaki and Levin 2011). "
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    • "The better in proportionality of LYSO:Ce is one of the important reasons behind its energy resolution. It appears so far, that all silicate scintillators (LSO, YSO, GSO or LGSO) exhibit large non-proportionality in the light yield [7] [11] [12] [13]. The non-proportionality characteristics of the studied crystals should be reflected in their intrinsic resolutions, as it is known that the non-proportionality in the light yield is a fundamental limitation to the intrinsic energy resolution [14] [15]. "
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    Procedia Engineering 11/2011; 32:765-771. DOI:10.1016/j.proeng.2012.02.010
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    • "shows the typical UV-excited luminescence spectra of one LYSO sample [10] [19] [20]. The other sample has similar result. "
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