Cancer Institute A national cancer institute
designated cancer center

Intensity Modulated Radiation Therapy

Stanford physicians and researchers were pioneers in the development and implementation of intensity modulated radiation therapy (IMRT), a method of delivering radiation to tumors with unprecedented precision.

How Intensity Modulated Radiation Therapy Works

Intensity modulated radiation therapy (IMRT) combines extremely precise tumor imaging techniques with special linear accelerators that can deliver hundreds of thin beams of radiation from any angle. Information fed into the linear accelerator allows it to revolve around the patient, delivering radiation in a three-dimensional patterns that corresponds to the exact tumor location.

The Benefits of Intensity Modulated Radiation Therapy

Targeting radiation to the tumor allows doctors to deliver the maximum dose of radiation to the cancer, while sparing healthy tissues. In addition, such accurate patterning of the radiation allows doctors to deliver radiation to places in the body that have been traditionally difficult to treat with radiation, such as the spinal cord, head (e.g., paranasal sinuses), neck, brain, liver, lungs, and prostate. In some cases, doctors can even deliver radiation to tumors that had been considered untreatable because they were too intertwined with vital organs.

In addition, IMRT can sometimes be combined with respiratory gating to precisely deliver radiation to tumors that could move when a patient breathes.

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