IMRT (Intensity Modulated Radiation Therapy) is a form of high-precision external radiotherapy where the dose of radiation administered by each of the beams is not uniform, but modulated in three-dimension shapes to administer a higher dose to the tumour while at the same time minimising the exposure of surrounding healthy tissue to radiation.
As IMRT enables the portion of dose in normal tissue to be very low compared to that of the tumour, it is possible to administer a much higher and more efficient dose of radiation to the tumour with fewer side effects than with conventional radiotherapy techniques. IMRT reduces the toxicity of the treatment.
IMRT is currently used to treat head and neck, prostate, breast, lung and central nervous system tumours. It is also used for gynaecological and liver tumours, lymphomas and sarcomas. IMRT is also useful for treating tumours in children.