LYSO (Lu 1.8Y.2SiO5:Ce) is a Cerium doped Lutetium-based scintillation crystal that offers several benefits compared to many common scintillation materials. LYSO offers high density and short decay time and an exceptional high photon-emission rate. It is ideal for applications that require higher throughput, better timing and energy resolution. This material has enabled the development of time-of-flight positron emission tomography (TOF-PET) imaging.
PET applications have traditionally used arrays of BGO. LYSO crystal competes directly on density and surpasses BGO on energy resolution, timing and throughput.
|Table comparing principal properties||LYSO||BGO||LSO|
|Attenuation length for 511 keV (cm)||1.2||1.0||1.15|
|Decay time [ns]||36||300||40|
|Energy resolution @ 662 keV||8.0||12.0||10.0|
|Light output, photons per keV||33||9||26|
|Average temperature coefficient 25 to 50oC (%/oC)||-0.28||-1.2||-1.3|
Compared to NaI(Tl) it has a high density (7.1 vs 3.67 g/cm3), very fast decay time (36 ns), comparable light yield (33200 ph/MeV), and is non-hygroscopic. With a peak wavelength emission of 420 nm, the output is well matched to the sensitivity curve of photomultiplier tubes (PMTs) with bialkali photocathodes, as well as silicon photomultipliers (SiPMs).
An engineered version of LYSO has recently been introduced which offers up to 20% more light yield and 6% better energy resolution than traditional LYSO. The 1/e decay time is 36ns for engineered LYSO crystal, which is much shorter than the decay time of BGO and traditional LYSO.
|Attenuation length for 511keV (cm)||1.2|
|Energy resolution [%] @ 662 keV *||8.0%|
|Wavelength of emission max [nm]||420|
|Refractive index @ emission max||1.81|
|Decay time [ns]||36|
|Light yield [photons/MeV] *||33200|
*Typical values tested using 1cm3 material against a calibrated standard; actual results can vary depending upon crystal size, shape and other factors.
Non-hygroscopic material that can be supplied as pixels or pixellated array