External Beam Radiation
The most common way of administering radiation as a cancer treatment is called external beam radiation. With this kind of treatment, a device (called a linear accelerator) is used to make high energy X-ray beams which are then aimed at the tumor. Because the X-ray beams can also damage healthy tissue, patients might have their therapy controlled by a computer program. This program will use imaging technology (such as an MRI) to find exactly where the cancer is and then guide the linear accelerator so that the highest dose of radiation can be accurately directed, causing minimal damage to the surrounding healthy tissue. External beam therapy is effective because it can be used to treat large areas of the body and multiple parts of the body. It usually is given daily for several weeks.
Brachytherapy
Brachytherapy differs from external beam radiation treatment because the radiation does not come from outside of the body. Instead, a small piece of radioactive material (called a seed) is surgically implanted next to the tumor. The radiation emitted by the seed does not travel very far, so it only damages tissue in very near proximity (such as the tumor). Sometimes the implanted material is only left in for 10 to 20 minutes. Other times, the seed can be left inside the body for up to 7 days. Permanent brachytherapy involves the implantation of very small seeds that eventually run out of radioactive material and are never removed.
Radiopharmaceuticals
Radiopharmaceuticals cannot be used for all types of cancer but they can be effective at treating certain cancer types. Radiopharmaceuticals consist of drugs that are made with radioactive material. The drug then travels through the body and binds to the cancer cells where it then emits radiation. Radiopharmaceuticals can be used to treat bone cancer, thyroid cancer or certain kinds of brain cancer.
