Our goal is development of an innovative brain-PET with effective sensitivity (8X) and higher spatial resolution vs. current advanced brain-PET systems by implementation of advanced ultrafast SiPM/readout systems coupled to thin monolithic crystals arranged in “onion ring” geometry with small air-gaps between the rings enabling accurate tracking of Compton Scatter (CS) events followed by photoelectric absorption (PE) events, forming “triplets” (PE =CS-PE). We performed Monte Carlo simulations of four concentric rings with diameters 250, 270, 290, 310 mm, and 508 mm axial length with monolithic 3-mm-thick LYSO thin-slab detector modules. The brain was simulated by a water sphere containing F-18. We considered only true-coincidence (PE=PE) and triplet (PE =CS-PE) events. For triplets, back-to-forward scatter ratio is 0.26. The triplet-to-true-coincidence events ratio is 0.30. Inclusion of triplets in addition to true-coincidence events allows sensitivity increase by ~30%. Because the point-of-first interaction is well defined, the improved spatial resolution is anticipated.
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