“This publication provides comprehensive, multidisciplinary guidance on the use of PRRNT in order to enhance the effective, safe and standardized implementation of best practice for treating patients with NETs and gastroenteropancreatic cancers, with due regard to the recent international classifications of NETs. It provides comprehensive protocols for employing either 90Y or 177Lu tagged somatostatin receptor targeting peptides, as well as clinically assessed protocols for renal protection. It is a comprehensive compilation of clinically based evidence with input from experienced and renowned medical professionals in this field. The various sections cover clinical presentations, patient eligibility criteria and means of assessing the effectiveness of therapy utilizing molecular and morphological medical imaging techniques.” This is No. 20 is the IAEA Human Health Series published in 2013 by the International Atomic Energy Agency.