Speaker
Description
Positron Emission Tomography (PET) imaging is based on measurement of energy and coincidence time of back-to-back gamma photons from positron annihilation. The annihilation quanta are entangled, and this fact is reflected in orthogonality of their initial polarizations, however it has not been utilized in clinical systems. We developed a demonstrator setup based on Compton polarimeters to measure the polarization correlations of annihilation quanta, and to assess the potential of this additional information to enhance PET. Two detector modules, comprising GAGG scintillator matrices with 3.2 mm pitch read out by silicon photomultipliers were used, and they performed with an energy resolution < 9.5% at 511 keV and coincidence time resolution of about 300 ps (FWHM). PET imaging tests done with source of clinically relevant activities from 90 MBq to 400 MBq, show that a spatial resolution from 3.6±0.3 to 4.9±0.3 mm can be achieved in the central field of view, using the polarization-correlated Compton events. We show that these events exhibit up to 20% higher signal to random background ratio, compared to conventional single-pixel events. Finally, we discuss how this concept can be advanced towards clinical application.