Evaluation of inorganic scintillators for high performance ToF PET applications

LSO and LYSO scintillators have become the preferred choice for PET scanners, thanks to their high effective Z, light yield, relatively good energy resolution and good timing properties which allow for coincidence resolving times of the order of 250 ps (FWHM) at the annihilation peak. However, very recently additional inorganic scintillators are becoming available, such as PrLuAG and HRCeGAG which hold a very high potential for PET application, either in single-scintillator arrangements or forming part of phoswich arrays with DOI capability. This work evaluates these scintillators in all relevant aspects for PET, such as energy resolution, coincidence time-resolving time, stopping power, photopeak to Compton ratio, internal activity, internal activity and optical compatibility for phoswich arrangements. As these parameters highly depend on the matching of the emission of the crystal to the photodetector employed, we evaluate these performance parameters with scintillators coupled to standard PMTs as well as to a range of SiPM currently available, from Hamamatsu, SensL, KetK, Advansis and Excelitas.