Radiotherapy uses high energy radiation in a very controlled way to treat cancer and other diseases of the body. Radiation works by damaging the DNA inside cells causing them to stop reproducing and die. Abnormal cancer cells are more sensitive to radiation because they divide more quickly than normal cells. Over time, the abnormal cells die and the tumor shrinks. Normal cells can also be damaged by radiation, but they can repair themselves more effectively, just like your skin heals after sunburn.
The main goal of radiation therapy is to maximize the radiation dose delivered to abnormal cells, such as cancer cells, while minimizing the dose received by normal cells surrounding them. This minimizes the chance of any side effects. The effects of ionizing radiation are not instant; the treatment benefit occurs over time. Typically, more aggressive tumors, whose cells divide rapidly, respond more quickly to radiation. Radiation therapy is painless treatment option and will not make patients radioactive.
Radiation is often given with the intent of destroying tumors and curing the diseases. However, not all cancer can be cured with radiation. Sometimes radiation is used to relieve symptoms, such as pain. or it is used to prevent tumors from developing or spreading. It may be used alone or in combination with other treatments such as surgery or chemotherapy. If used before surgery, it will shrink the tumor to make it easier to remove. And, if used after surgery, it will destroy tumor cells that may have been left behind.