Towards 100 ps PET Detectors Suitable for High-Resolution Brain Mouse Imaging

Many efforts have been devoted over the years to enhance the capabilities of PET detectors and to develop novel and efficient scanner concepts. Indeed, following several technological advances, the standards in the performance of these detectors have now been greatly expanded. However, in several cases compromises have to be made. In this work, we present our approach to develop an ultra-high spatial and timing resolution PET system, making use of the Compton-PET concept for mouse brain imaging. In particular, we will describe the detector elements of the scatter layer of such PET configuration. For this purpose, scintillators with just 3 mm thickness are tested when coupled to SiPM arrays of 3 mm × 3 mm. The aim, is to explore the optimal detector configuration for sub-100 ps resolution scanners. We make use of detectors based on crystal arrays of 0.95 mm × 0.95 mm pixel (12×12 elements) of the type LYSO(Ca) coupled to SiPMs arrays with 3 mm × 3 mm active area. As it will be discussed, we have been able to reach a detector timing resolution of 100 ps FWHM in some cases, while we were also capable to resolve all crystal pixels of 0.95 mm size.