Clinical applications of PET/CT, mostly in oncology, with FDG and non-FDG radiopharmaceuticals (68Ga-DOTANOC, 18F-DOPA, 11C-Colina, 11C-Metionina, 68Ga-PSMA) for staging, early assessment of therapy response, identification of the primary tumour site in patients with known secondary lesions, early detection of disease relapse after therapy. In particular, use of PET/CT and theranostic applications in neuroendocrine neoplasms.