This lecture covers typical PET tracers used in oncology and neuroscience, including 18Fluoroethyl-Tyrosine (FET), Deoxy-18fluoro-thymidine (FLT), 18Fluoromisonidazole (FMISO), and 18Fluoro-Deoxyglucose (FDG). It explains their roles in imaging proliferation, hypoxia, amino acid transport, metabolism, and blood flow.