Molecular Imaging and Theranostics: PET/CT and PET/MRI in Clinical Oncology and Beyond

Molecular imaging using positron emission tomography combined with CT or MRI has redefined the diagnostic and therapeutic landscape in oncology and beyond, enabling in vivo visualisation of metabolic, receptor, and gene expression targets. This chapter reviews the radiopharmacological basis and clinical evidence for established and emerging PET tracers, including PSMA, FDG, and FAPI ligands, and examines the growing theranostic paradigm in which diagnostic imaging informs targeted radionuclide therapy.