Various Aspects of Fasting on the Biodistribution of Radiopharmaceuticals

Abstract

It is demonstrated that fasting can alter the biodistribution of radiopharmaceuticals in nuclear medicine. Various studies have highlighted that fasting is interpreted to be easy for physicians during PET study, fasting is one of the most important factors determining the usefulness of this protocol. It is well documented that fasting can suppress normal 18F-FDG PET uptake during nuclear cardiology. However, there is no consensus about the usefulness of fasting on radiopharmaceuticals, especially on 18F-FDG in PET imaging, but special attention should be paid to the setting of the fasting duration. Nevertheless, it does seem we still need extensive clinical studies in the future. The present study aims to review the various aspects of fasting, especially metabolic alteration on radiopharmaceutical biodistribution. In this study, we more focused on the effect of fasting on 18F-FDG metabolism which alter its imaging contrast in cardiology and cancer imaging. Therefore, shifting substrate metabolism from glucose to free fatty acids during fasting can be used as an alternative approach to suppress physiological myocardial uptake.