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→Radiation Therapy
Radiation therapy is used as a primary, curative treatment, as a palliative treatment, and/or as adjunctive therapy. It can be used pre-operatively or post-operatively, and in combination with chemotherapy, biologic agents, and hormonal agents. The radiation dose prescribed to achieve tumour control is often limited by the radiosensitivity of normal tissues, which are located around the tumour, and thus may result in early and late adverse side effects. Some adverse effects are unavoidable and often resolve spontaneously or with treatment. Serious adverse effects may occur and result from the proximity of sensitive normal tissues to the treatment area. However, such adverse side effects do not undermine the purpose of radiation therapy. Appropriate use of radiation therapy saves millions of lives every year. Even if only palliative treatment is possible, the therapy reduces suffering substantially. There are also a few non-malignant diseases whose treatment by radiation is a method of choice. Note that palliative radiotherapy and radiotherapy of non-malignant diseases uses much lower doses, generally not inducing any acute side effects.
Radiation therapy has benefited greatly from technological advances over the past two decades, resulting in a wide variety of available delivery methods: Intensity-modulated radiation therapy (IMRT) utilizing techniques to quantify the critical normal tissue doses; Image-guided radiotherapy (IGRT) utilizing real-time imaging for treatment localization during radiotherapy; Stereotactic radiosurgery (SRS) delivering of a large dose per fraction to treat focal brain lesions and its extension, stereotactic body radiation therapy (SBRT), to treat focal lesions in the lung, spine, liver, pancreas, prostate and all parts of the body; Particle beam radiotherapy utilizing protons, neutrons or other heavy particles; Brachytherapy placing sealed radioactive sources near the tumor; Intraoperative radiotherapy (IORT) delivering to the surgical bed after removal of the tumor or to the tumor itself at the time of surgery; Unsealed sources delivering a radiopharmaceutical orally or parenterally; and Hyperthermia adding of heat to radiotherapy.