This lecture introduces the fundamental principles of FDG PET/CT imaging, focusing on the cellular and biochemical mechanisms that govern FDG uptake, trapping, and elimination. The session explains how FDG behaves as a radiolabeled glucose analog, how it enters cells through glucose transporters, and how intracellular phosphorylation leads to metabolic trapping that forms the basis of PET imaging. The lecture also reviews the roles of GLUT transporters, hexokinase, glucose-6-phosphatase, and tissue-specific metabolic activity in determining physiologic and pathologic FDG distribution. Finally, it highlights the importance of patient preparation, blood glucose regulation, and renal elimination in optimizing image quality and interpretation.

Learning Objectives

By the end of this lecture, participants will be able to:

• Describe the molecular structure of FDG and explain how it differs from native glucose.
• Explain the roles of GLUT transporters, hexokinase, glucose-6-phosphatase, and intracellular metabolic pathways in FDG handling.
• Understand the mechanism of FDG metabolic trapping and its importance in PET imaging.
• Identify the factors that influence FDG uptake and retention across different tissues and organs.
• Explain how fasting status, insulin activity, and blood glucose levels affect FDG biodistribution and image quality.
• Describe the physiologic renal handling and urinary excretion of FDG.
• Correlate FDG pharmacokinetics with physiologic and pathologic PET imaging findings.