Feasibility of myocardial perfusion imaging with half the radiation dose using ordered-subset expectation maximization with resolution recovery software

Objective. This study sought to assess the feasibility of performing myocardial perfusion imaging (MPI) with half the technetium activity using ordered-subset expectation maximization with resolution recovery (OSEM-RR), an iterative reconstruction software developed to improve count statistics and acquisition time. Methods. Two hundred eighteen patients referred for MPI were randomly allocated to undergo stress-rest or rest-stress protocols with standard full-dose (FD) injections of technetium (Tc)-99m sestamibi or half-dose (HD) injections and OSEM-RR processing. Dose activities were adjusted individually by weight. The groups were compared for image quality and clinical results. Results. The groups were similar for mean patient age, weight, and body mass index, sex distribution, pre-test probability of CAD and CAD prevalence. Mean Tc-99m activities for the low-dose and high-dose stages were as follows: FD group: 429 ± 85 MBq and 1132 ± 200 MBq; HD group: 263 ± 129 MBq and 629 ± 85 MBq (P < .0001 for both). Mean effective dose per study was 13.6 ± 1.4 mSv in the FD group and 7.7 ± 1.0 mSv in the HD group (P < .001). Over all image quality was good-to-excellent in 98% and 95% of the groups, respectively. However, when we analyzed the low-dose stage separately, image quality was slightly worse in the HD than the FD, though still within the good-to excellent range. Conclusions. MPI with nearly half the radiation dose is feasible with good image quality.