Intensity Modulated Radiation Therapy (IMRT)
IMRT is an advanced form of external beam radiation therapy that is commonly used to treat breast, prostate, lung, head and neck and many other types of cancer. IMRT allows doctors to customize the radiation dose by modulating, or varying, the amount of radiation given to different parts of the area being treated. The radiation intensity is adjusted with the use of computer-controlled, moveable "leaves" which either block or allow the passage of radiation from the many beams that are aimed at the treatment area. The leaves are carefully adjusted according to the shape, size, and location of the tumor. As a result, more radiation can be delivered to the tumor cells while less is directed at the normal cells that are nearby. Unlike standard radiation techniques that allow only a constant flow of radiation from each beam, IMRT allows radiation oncologists to "paint" the radiation dose.