What is Radiation therapy?
[[File:Ghanaian Radiotherapists at work.jpg|thumb|Radiation therapy in [[Accra]] ([[Ghana]])]] '''Radiation therapy''' is the use of [[radiation]] to treat diseases. It is typically used to [[therapy|treat]] of [[cancer]]. It may use a radioactive material or [[particle accelerator]] or other source of [[ionizing radiation]] that can kill or damage cancerous cells. Radiation therapy may help cure several different types of cancer if they are limited to one area of the body. Doctors also use it to prevent tumor recurrence after surgery to remove a primary malignant [[tumor]] (for example, early stages of [[breast cancer]]). Radiation therapy works together with [[chemotherapy]]. Radiation therapy has been used before, during, and after chemotherapy in cancers known to be affected by radiation. Radiation therapy is used on tumors because of its ability to control [[cell growth]]. [[Ionizing radiation]] works by damaging the [[DNA]] of exposed tissue thus killing it. To spare normal [[Tissue|tissues]] (such as skin or organs which radiation must pass through in order to treat the tumor), doctors aim weaker radiation beams from several angles of exposure. The beams intersect at the tumor, providing a much larger [[absorbed dose]] there than in the surrounding, healthy tissue. Besides the tumor itself, the target for the radiation may also include the [[lymph node]]s that drain the area. Doctors include the lymph nodes if they are clinically or radiologically involved with tumor, or if there is thought to be a risk of that individual cancer cells will spread. It is impossible to aim the radiation beam exactly because the tumor moves as the patient [[wikt:breathes|breathes]]. So, doctors also expect to include some healthy tissue around the tumor to make sure that the entire tumor is hit by radiation. Radiation [[oncology]] is the medical specialty concerned with prescribing radiation. This is different than [[radiology]], the use of radiation in [[medical imaging]] and [[medical diagnosis|diagnosis]]). Radiation