Targeted Radionuclide Therapy
Targeted radionuclide therapy is a form of treatment that delivers therapeutic doses of radiation to malignant tumors by administering a molecule that is labeled with a radionuclide. The radiotherapeutic agent is made of two components: the radionuclide and the carrier that is used to seek out the tumor cells. Molecular carriers that can be used include, but are not limited to, peptides that seek their corresponding receptors on cells, and monoclonal antibodies that seek out antigens that are similarly expressed on the cells, as shown in the figure.
The radionuclide that is attached to the carrier molecule can be chosen for specific characteristics, such as type of radiation decay (e.g., alpha-emitter, beta-emitter), radiation range, and half-life. It is this modular nature, where the two components can be varied like Lego® pieces to match characteristics specific to the tumor that makes targeted radionuclide therapy an attractive approach to cancer treatment (Zalutsky 2003). To date, two antibody radiopharmaceuticals have been approved by the FDA (yttrium-90-ibritumomab tiuxetan and iodine-131-tositumomab) for the treatment of lymphoma.