Peptide receptor radionuclide therapy is a type of radiopharmaceutical therapy which is given to patients through an intravenous infusion. This treatment is prescribed for patients who have advanced neuroendocrine tumours. Neuroendocrine tumours are sensitive to radiation and commonly overexpress certain types of somatostatin receptors. A radioactive material is bound to a drug which targets these receptors – this is called a radiolabelled peptide. The radiolabelled peptide is taken into the tumour cells, where radiation can exert its effects. The radionuclide used in this therapy is usually Lutetium 177 (Lu-177).