IMRT, or intensity modulated radiation therapy, is typically used for treating smaller, stationary tumors surrounded by normal tissue - or by critical structures, such as organs or blood vessels. The types of tumors most often treated with IMRT include those involving the brain, head, and neck, the prostate, spinal cord and tumors that are quite close to normal tissues that are radiosensitive, such as the optic nerve. Tumors that are not candidates for IMRT include those that are too mobile or too large.



Radiation therapy is used to deliver a targeted dose of radiation to the tumor while limiting the amount received by the area surrounding it. IMRT calculates the dose and the delivery in a sophisticated manner so that the tumor is irradiated precisely. This precision is achieved using a linear accelerator with computer-controlled radiation shields.

Procedure information
In the IMRT procedure, small beams of radiation are directed at the tumor from several angles. During each treatment, the intensity of each beam of radiation is carefully controlled; and the shape of the beam changes multiple times. This allows the radiation dose to bend around adjacent healthy tissues in a manner unique to this type of treatment.

Radiation oncologists administer a series of IMRT treatments over a course of four to eight weeks. The radiation dose and the number of treatments will depend on the tumor’s size and location, the overall health of the patient, and other treatments the patient is undergoing.

Recovery time
After recovering from the IMRT treatment, the patient is allowed to leave hospital. Some patients report a feeling of weakness, so it is important that they are accompanied by someone able to drive them home. The weakness typically subsides after approximately 12 hours. Eating and moderate activity can then be resumed.

One of the benefits of intensity modulated radiation therapy is the improvement of recovery time in patients and the reduction in side effects and other complications that can arise from conventional radiation therapy.