IMRT is an advanced form of 3D therapy. It uses Turville Bay’s Linear accelerator, a computer-driven machine, to actually move around the patient as it delivers radiation. In addition to shaping the beams and aiming them at a specific area from several angles, the intensity (strength) of the beams can be adjusted to minimize the dose reaching the most sensitive normal tissues. IMRT actually varies the intensity of the radiation therapy according to the dimensions of the cancer in three dimensions. A single IMRT beam is composed of many small “beamlets”; each can be a different intensity. Very complicated cancer shapes can be recreated, with rapid fall-off of dose immediately outside the cancer.
This allows the radiation to be more focused on the tumor cells, sparing much of the surrounding healthy tissue and leaving tumors unable to divide and spread.
Not everyone is a candidate for IMRT. Prostate, brain, head and neck, and gastrointestinal are some of the more common disease sites that may be appropriate.