Medically reviewed by Tobin C. Hyman, MS, DABR Chief Medical Physicist
Radiation therapy for cancer is delivered in two primary forms: External, in which a large x-ray generator sits outside the patient directing beams into the patient and Internal, where the radiation is placed inside the patient mere millimeters from the tumor or directly inside the tumor. Internal Radiation Therapy is also called Brachytherapy. Roughly translated, it means “short distance therapy” – it’s a short distance between the radiation and the tumor. A small thin tube – called a catheter – is used to deliver radioactive solids to the site of the cancer. Solids can be capsules, seeds, micro-spheres, or ribbons about the size of a grain of rice. Other methods of internally delivering radioactive material to the site of the disease/tumor include ingestion of a pill (ex., for thyroid cancer) or injection/infusion through an IV (ex., for bone cancer).