Monte Carlo Assessment of Entanglement-Based Positron Emission Tomography

Monte Carlo simulations were conducted to evaluate the coincidence selection performance in the conventional and Compton-based positron emission tomography systems under identical geometric and activity conditions. A ring detector composed of eight 8 x 8 Ce:GAGG crystal array modules was modeled using the Geant4 toolkit, with annihilation events generated to mimic fluorine-18 decay. Two performance metrics were examined, i.e., the relative true event detection efficiency and the true event fraction (both computed as functions of the coincidence time window). The Compton configuration yielded fewer total true coincidences than conventional positron emission tomography but achieved a consistently higher true event fraction, indicating improved rejection of random and scattered events. Simulations performed for low- and high-activity conditions, incorporating both entangled and non-entangled annihilation photon states, showed that entanglement further enhanced the true event fraction, particularly at lower activity, where accidental coincidences were less dominant. The enhancement observed at A ≈ 0.167 GBq corresponded to only a few percent increase in true event fraction, but the effect was systematic across the tested coincidence windows. These findings demonstrate that coincidence selection using quantum polarization correlations can enhance selection fidelity under relaxed timing conditions and suggest a potential pathway toward more timing-tolerant positron emission tomography architectures.