Radiation Therapy for Prostate Cancer

External beam radiation therapy (also called radiotherapy) involves a series of daily treatments to accurately deliver radiation to the prostate. There are several ways to deliver external beam radiation.


Before treatment, you will have a scan to allow the radiation oncologist to target the radiation on the cancer. Usually several radiation beams are combined to shape, or “conform”, the radiation to the prostate cancer. This technique is called three-dimensional conformal radiation therapy or 3D-CRT. Tailoring each of the radiation beams to accurately focus on the tumor allows doctors to target the prostate cancer while keeping radiation away from nearby organs such as the bladder or rectum.

Some doctors use a type of 3D-CRT called intensity modulated radiation therapy or IMRT. IMRT allows doctors to change the intensity of the radiation within each of the radiation beams. In some cases, this lets doctors increase the radiation to the prostate while reducing radiation to nearby normal tissues.

In a few clinics in the country, proton beam therapy is used to treat prostate cancer. Proton therapy is a form of external beam radiation that uses protons rather than X-rays to treat cancer cells. Proton therapy is precise like IMRT only it uses a different kind of radiation.

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