How Radiation Therapy Works Radiation therapy, sometimes called radiotherapy, effectively treats cancer by using high-energy rays to pinpoint and destroy cancerous cells in your body. Although radiation therapy is similar to having an x-ray taken of a broken bone, the dose of radiation in cancer treatment is stronger and is given over a longer period of time. Many forms of radiation are available. The best choice for you depends on the type of cancer you have, the extent of the cancer, and its location.
Cancers are growths of abnormal cells.
Different types of cancer react to radiation in different ways, so treatments vary. Also, it takes time for the body to get rid of dead cancer cells. After you have completed treatment, months often pass before the tumor is completely gone. With careful planning, radiation can be directed to the cancer and away from most normal tissues. This means you may receive treatment on more than one side of your body or from different angles.