Branch of medicine that deals with the use of radiant energy including X rays, gamma rays, radiowaves, high frequency sound waves in the diagnosis and treatment of disease.

Radiopaque dye (one that is highlighted on x-rays) is used in cerebral angiograms to detect the degree of narrowing or obstruction of an artery or blood vessel in the brain, head, or neck; in the diagnosis of stroke, determining the location and size of a brain tumor, aneurysm, or vascular malformation.

Requiring high radiation therapy doses with associated high risks.

Sensitive to the effects of radiant energy.

See stereotactic radiosurgery.

One who practices radiotherapy or is versed in radiotherapeutics.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

A tumor that has recurred (grown back), usually after a period of time following removal of the tumor.

A process to restore mental and/or physical abilities lost to injury or disease, in order to function in a normal or near-normal way. Rehabilitation can include; pain management, physical therapy, occupational therapy, speech-language therapy.

Deep sleep with rapid eye movements in which dreaming takes place. One of the five stages of sleep. During REM sleep, the eyes move rapidly while closed and dreams occur. REM sleep is the lightest stage of sleep, during which a person may wake easily. During several hours of normal sleep, a person will go through several sleep cycles that include REM sleep and the 4 stages of non-REM (light to deep sleep). Also called rapid eye movement sleep.