Dosimetric studies demonstrated that 90Y-DOTATOC and 177Lu-DOTATATE are able to deliver high radiation doses to somatostatin receptor sst2-expressing tumors and low doses to normal organs. Clinical studies demonstrated that partial and complete objective responses in up to 30% of patients can be obtained, with a great survival benefit including those with stable disease. Side effects may involve the kidney and the bone marrow and are usually mild. Renal protection is used to minimize the risk of a late decrease of renal function.