Intensity-Modulated Radiation Therapy
Intensity-modulated radiation therapy (IMRT) is an advanced mode of high-precision radiotherapy that utilizes computer-controlled x-ray accelerators to deliver precise radiation doses to a malignant tumor or specific areas within the tumor. The radiation dose is designed to conform to the three-dimensional (3-D) shape of the tumor by modulating or controlling the intensity of the radiation beam to focus a higher radiation dose to the tumor while minimizing radiation exposure to surrounding normal tissues.
Treatment is carefully planned by using 3-D computed tomography (CT) images of the patient in conjunction with computerized dose calculations to determine the dose intensity pattern that will best conform to the tumor shape. Typically, combinations of several intensity-modulated fields coming from different beam directions produce a custom tailored radiation dose that maximizes tumor dose while also protecting adjacent normal tissues.
Radiation Doses with Pinpoint Accuracy
Because of its pinpoint accuracy, IMRT can allow for higher and more effective radiation doses to tumors while minimizing damage to normal tissue. This translates to fewer side effects compared with conventional radiotherapy techniques. IMRT also has the potential to reduce treatment toxicity, even when doses are not increased.
Radiation therapy, including IMRT, stops cancer cells from dividing and growing, thus slowing tumor growth. In many cases, radiation therapy is capable of killing cancer cells, thus shrinking or eliminating tumors.