Optimization of positroniumimaging performance ofa simulated modular J-PET scannerusing GATE software

Abstract

Recently, a novel PET imaging method – positronium imaging – has been proposed to take advantage of previously unused information about the positronium states. The first <i>ex-vivo</i> and <i>in-vivo</i> images of positronium characteristics were acquired with the J-PET tomograph. Complementary to the standard annihilation photon’s detection, positronium imaging also requires the registration of the prompt photon, which follows β+ decay. To that end, the introduction of an additional energy threshold for prompt γ registration and optimization of the energy window for annihilation γ are required. This simulation-based work undertook the mentioned task in the case of the modular J-PET scanner. Based on the <sup>44</sup>Sc radioisotope, the energy window for annihilation photons was established to 0.2 MeV – 0.37 MeV, while the threshold for prompt gamma was fixed at 0.37 MeV, closely following the end of the energy window for annihilation photons.