Intensity Modulated Radiation Therapy
Radiation therapy can be delivered in two ways, externally and internally. During external beam radiation therapy, the radiation oncology team uses a machine to direct high-energy X-rays at the cancer. Internal radiation therapy, called brachytherapy, involves placing radioactive sources (for example, radioactive seeds) inside your body.
Intensity modulated radiation therapy, or IMRT, is a specialized form of 3D-Conformal Radiation Therapy (CRT) that enables radiation to be more exactly shaped to fit the tumor. Intensity modulated radiation therapy is a form of external beam radiation therapy whereby the radiation beam can be broken up into many “beamlets,” and the intensity of each beamlet can be adjusted individually. Using IMRT, it may be possible to further limit the amount of radiation received by healthy tissue near the tumor. In some situations, this also may safely allow a higher dose of radiation to be delivered to the tumor, potentially increasing the chance of a cure.
There are several types of external beam therapies. Your radiation oncologist will determine which to use based on the type of cancer you have.