Medical Definition of Intensity modulated radiation therapy
Intensity modulated radiation therapy: IMRT. A type of three-dimensional radiation therapy that uses computer-generated images to match radiation to the size and shape of a tumor. In IMRT, thousands of tiny radiation beamlets enter the body from many angles and intersect the tumor. Since the intensity of each beamlet can be controlled, the radiation dose can wrap around normal tissue, create concave shapes and turn corners. The aim is to deliver a higher radiation dose to a tumor with less damage to nearby healthy tissue. IMRT may be used, for example, to treat a tumor that surrounds the spinal cord and spare the cord itself.
Last Editorial Review: 6/9/2016
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