Hi Christine,
The basic difference between IMRT (Intensity Modulated Radiation Therapy) and XRT (Standard Radiation therapy) is that IMRT specifically targets the tumor, avoiding damage to healthy tissue as much as possible. XRT is more of a "shotgun" approach where a larger treatment area is involved. Both treatment modalities deliver about the same amount of radiation.

IMRT requires additional information like CT and/or MRI data to develop the software programming necessary to accurately model the shape of the tumor and other areas of interest like lymph nodes in 3D and optimize radiation beam entry points to avoid tissue damage. Not all persons are candidates for IMRT. If the tumor is not well contained (differentiated) then XRT may be a safer, more effective choice.

IMRT can dramatically improve post treatment quality of life by sparing some of the salivary glands and minimizing radiation through the thyroid and spinal cord.

IMRT was first utilized around 1995 for prostate cancer and new applications for it are being found all of the time. Typically only more advanced treatment centers offer it but that is changing rapidly as more of the regional treatment centers update their equipment.

Never the less, radiation in any form is still a very aggressive and potent treatment and will have side effects that are covered in other areas of the site.

For technical detail on IMRT go to: http://www.medical.siemens.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-20&catalogId=-20&catTree=100001%2C12789%2C12757&level=0&productId=17251&x=9&y=4