IMPROVING PET SCANNER TIME-OF-FLIGHTRESOLUTION USING ADDITIONAL PROMPT PHOTON

Abstract

Positronium Imaging requires two classes of events: double-coincidences originated from pair of
back-to-back annihilation photons and triple-coincidences comprised with two annihilation photons
and one additional prompt photon. The standard reconstruction of the emission position along the
line-of-response of triple-coincidence event is the same as in the case of double-coincidence event;
an information introduced by the high-energetic prompt photon is ignored. In this study, we propose
to extend the reconstruction of position of triple-coincidence event by taking into account the time
and position of prompt photon. We incorporate the knowledge about the positronium lifetime distribution
and discuss the limitations of the method based on the simulation data. We highlight that the
uncertainty of the estimate provided by prompt photon alone is much higher than the standard deviation
estimated based on two annihilation photons. We finally demonstrate the extent of resolution
improvement that can be obtained when estimated using three photons.