External Beam Radiation

External beam radiation It is a common cancer treatment that uses high doses of radiation to destroy cancer cells and shrink tumors. A large machine aims radiation at the cancer. The machine moves around you without touching you. At low doses, radiation is used as an x-ray to take pictures inside your body. In cancer treatment, higher doses of radiation are used to destroy cancer cells. The radiation that destroys cancer cells also injures nearby healthy cells. This is why you may have some side effects.