Radiation therapyRadiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis). Although radiotherapy is often used as part of curative therapy, it is occasionally used as a palliative treatment, where cure is not possible and the aim is for symptomatic relief.
Radiotherapy is commonly used for the treatment of tumours. It may be used as the primary therapy. It is also common to combine radiotherapy with surgery and/or chemotherapy. The most common tumours treated with radiotherapy are breast cancer, prostate cancer, rectal cancer, head & neck cancers, gynaecological tumours, bladder cancer and lymphoma.
Radiation therapy is commonly applied just to the localised area involved with the tumour. Often the radiation fields also include the draining lymph nodes. It is possible but uncommon to give radiotherapy to the whole body, or entire skin surface.
Although the actual treatment is painless, using radiation to tackle tumours inevitably leads to side effects. The side effects can occur during treatment (acute side effects such as soreness and redness over the affected area; nausea and vomiting) or long after treatment has finished (late side effects reflecting permanent organ damage).
Radiation therapy is usually given daily for up to 35-38 fractions (a daily dose is a fraction). These small frequent doses allow healthy cells time to grow back, repairing damage inflicted by the radiation. Tumours don't repair the radiation damage as well.
Three main divisions of radiotherapy are external beam radiotherapy or teletherapy, brachytherapy or sealed source radiotherapy and unsealed source radiotherapy. The differences relate to the position of the radiation source; external is outside the body, while sealed & unsealed source radiotherapy has radioactive material delivered internally. Brachytherapy sealed sources are usually extracted later, while unsealed sources are injected into the body.
- http://www.rtog.org/ - The Radiation Therapy Oncology Group