Revisit 18F-fluorodeoxyglucose oncology positron emission tomography: "systems molecular imaging" of glucose metabolism.

18F-fluorodeoxyglucose (18F-FDG) positron emission tomography has become an important tool for detection, staging and management of many types of cancer. Oncology application of 18F-FDG bases on the knowledge that increase in glucose demand and utilization is a fundamental features of cancer. Pasteur effect, Warburg effect and reverse Warburg effect have been used to explain glucose metabolism in cancer. 18F-FDG accumulation in cancer is reportedly microenvironment-dependent, 18F-FDG avidly accumulates in poorly proliferating and hypoxic cancer cells, but low in well perfused (and proliferating) cancer cells. Cancer is a heterogeneous and complex "organ" containing multiple components, therefore, cancer needs to be investigated from systems biology point of view, we proposed the concept of "systems molecular imaging" for much better understanding systems biology of cancer.This article revisits 18F-FDG uptake mechanisms, its oncology applications and the role of 18F-FDG PET for "systems molecular imaging".