Systemic Radiation Therapy
In systemic radiation therapy, patients swallow or receive an injection of a radioactive substance, such as a radioactive isotope or a radioactive isotope bound to a monoclonal antibody.
Radioactive iodine (131I) is a type of systemic radiation therapy commonly used to help treat some types of thyroid cancer. Thyroid cells naturally take up radioactive iodine. Some systemic radiation therapy drugs relieve pain from cancer that has spread to the bone (bone metastases). This is a type of palliative radiation therapy. Palliative treatments are not intended to cure. Instead, they relieve symptoms and reduce the suffering to improve quality of life. The radioactive drugs samarium-153-lexidronam and strontium-89 chloride are examples of radiopharmaceuticals used to treat pain from bone metastases.
For systemic radiation therapy for some other types of cancer such as lymphomas, a monoclonal antibody helps target the radioactive substance to the right place. The antibody joined to the radioactive substance travels through the blood, locating and killing tumor cells.