Application of Total-Body PET/CT in Evaluation of Radiotracer Biodistribution in Human

One of the advantages of positron emission tomography–computed tomography (PET/CT) lies in its ability to quantify the in vivo distribution, metabolism, and clearance of the tracer, from which a series of pathophysiological processes of tumor metabolism can be revealed at the molecular level, for example, tumor metabolism, blood perfusion, proliferation, receptor expression, and the binding between the ligand and receptor. 2-[18F]Fluoro-2-deoxy-D-glucose (18F-FDG) PET/CT imaging and its semiquantitative parameter standardized uptake value (SUV) have played a significant role in the diagnosis and treatment of tumors and thus have been widely used. However, the static imaging acquired over a relatively long time (about 60 min) after tracer administration can only provide limited information from single time point of whole tracer metabolism. In contrast, dynamic PET imaging allows for the quantitative assessment of the characteristics of the key steps regarding blood perfusion, delivery, tissue uptake, retention, and release of the tracer, and thus can non-invasively represent the whole process of tumor metabolism, which would facilitate to the accurate treatment and diagnosis of the tumor.