Targeted Radionuclide Therapy or Peptide Receptor Radionuclide Therapy (PRRT) is a medical specialty in nuclear medicine using very small amounts of radioactive materials, called radiopharmaceuticals, to diagnose and treat various diseases, like cancer. Targeted radiopharmaceuticals in molecular therapy contain a targeting molecule and a medical radioisotope complexed with a chelating agent.
The targeting molecule binds to the tumor specific receptor according to the lock and key principle. In most cases the targeting molecule can be used for both diagnostics and therapy - only the radioisotope has to be changed. This opens up the way for the application of Theranostics in the field of Precision Oncology. The technique works by injecting into the patient’s body the targeted radiopharmaceuticals that accumulate in the affected organs or lesions.
For diagnostic applications radioisotopes with short half-lives are used. With highly sensitive molecular imaging technologies like PET (Positron Emission Tomography) or SPECT (Single Photon Emission Tomography), pictures of organs and lesions can be created and therefore, diseases can be diagnosed in their early stages.
Medical radioisotopes with longer half-lives are applied for treatment. To destroy the tumor, cytoxic doses of ionizing radiation have to be submitted to the tumor site before decay. A highly precise localization of the toxicity ensures that healthy tissue in the surroundings of the targeted tumor is minimally affected.