Radiation therapy, or radiotherapy, uses ionizing radiation produced by a linear accelerator (LINAC) to destroy cancer cells and shrink tumors. The radiation passes through the body and delivers dose to the affected area while minimizing dose to the skin and tissue it passes through.
Although the radiation affects both cancerous and normal cells, it has a greater effect on the cancer cells, damaging their genetic material and making it impossible for these cells to continue to grow and divide. Treatment aimed to cure will give the highest possible dose of radiation to the cancerous area (within safe limits) to attempt to destroy all the cancer cells. Sometimes smaller doses are used, with a goal to reduce the size of a tumor and/or relieve symptoms.
Most patients undergo radiation therapy once a day, five days per week, over a period lasting from two to 10 weeks. The total time, beginning with your first and ending with your last session, is called a course of treatment. Some patients are prescribed hypofractionated radiation therapy, which delivers higher doses of radiation in a more targeted fashion over fewer treatments.
Electrons are used to treat skin cancers and other superficial lesions as they are absorbed by the first few centimeters of skin, leaving very little dose to pass into the body. Radiation therapy is used to both cure disease and alleviate the symptoms of cancer. There are also a number of non-malignant conditions that are treated using radiation therapy.