Optimizing reconstruction parameters for quantitative 124I-PET in the presence of therapeutic doses of 131I

Abstract Background The goal of this work was to determine the quantitative accuracy and optimal reconstruction parameters for 124 I-PET imaging in presence therapeutic levels 131 I. In effort, images were acquired on a GE D710 PET/CT scanner using NEMA IEC phantom with spheres containing I increasing amounts activity background. At each level, two scans acquired, one centered field view (FOV) 11.2 cm off-center. Reconstructions used an ordered subset expectation maximization algorithm up 100 iterations 16 subsets, without time-of-flight (TOF) information. Results evaluated visually by comparing relative scan performed absence within FOV added randoms rate, dead time, pile-up detectors. Using our standard clinical parameters, image quality suffered at activities above 1.4 GBq. Convergence rates slowed progressively both TOF nonTOF reconstructions. reconstructions converged more quickly than but often towards erroneous concentrations. Iterating convergence produced quantitatively accurate except off-center very highest level background tested. Conclusions This study shows that PET is feasible large high fractions resulted slow negatively impacted corrections and/or Therefore, increased are recommended.