Cancer treatment that delivers radioactive atoms directly to tumor cells using a targeting molecule—like a guided missile with a radioactive warhead.Peptide receptor radionuclide therapy (PRRT) uses radiolabeled peptides to deliver targeted radiation to tumors expressing specific receptors. Lutathera (¹⁷⁷Lu-DOTATATE) targets SSTR2-positive neuroendocrine tumors, delivering beta radiation selectively to tumor cells while sparing normal tissue. The NETTER-1 trial demonstrated significant progression-free survival benefit. PRRT represents a paradigm where peptide receptor specificity enables precision oncology—the peptide provides targeting, the radionuclide provides cytotoxicity.