Objective: Fluorine-18-fluorodeoxyglucose (18F-FDG) injection activity is positively associated with radiation dose and positron emission tomography (PET) image count. Measurement error is greater with smaller counts; therefore, precise analysis is needed to avoid high doses of radiation exposure caused by high 18F-FDG injection. We aimed to identify and validate the optimal 18F-FDG injection activity and acquisition time for cardiac viability imaging with intravenous insulin preparation administration based on fixed 18F-FDG activity.
Materials and methods: Cardiac PET images from 30 patients with coronary artery disease (CAD) were retrospectively reconstructed into different durations. An optimal product of the maximum standardized uptake value (SUV) of the myocardium, and segmental uptake (SU), and acquisition time (MSAT) was determined through a receiver operating characteristic curve.
Results: The optimal acquisition time (OAT) was equal to MSAT divided by mean SUV of the myocardium (MyoSUV) and was validated in another 26 patients with CAD. The optimal MSAT was 848.2s. In the validation group, the OAT was 129±76s (95% confidence interval, 99-160s), approximately one-third of the usual acquisition time. The MyoSUV and SU were equivalent between PET image duration of OAT and 600s (7.71±3.01 vs. 7.56±2.94; 67.1±15.4% vs. 67.7±15.6%).
Conclusion: Intravenous insulin preparation administration has the potential to decrease the radiation exposure or acquisition time in cardiac viability 18F-FDG imaging to one-third, without losing the accurate measurement of MyoSUV or SU when reaching an OAT.