Radiation Therapy for Breast Cancer

External Beam Radiation Therapy

Painless radiation treatments are delivered in a series of sessions Monday through Friday, for three to eight weeks. Each treatment lasts less than 30 minutes. The radiation beam usually comes from a machine called a linear accelerator or a linac.

• Before beginning treatment, you will be scheduled for a simulation to map out the area being treated. This will involve having X-rays and/or a CT scan. You may also receive tiny marks on your skin, like a tattoo, to help the radiation therapist precisely position you for daily treatments.
• The usual course of radiation treats only the breast, although you may need to have nearby lymph node areas treated also.
• 3-dimensional conformal radiotherapy (3D-CRT) combines multiple radiation treatment fields to deliver very precise doses of radiation to the breast and spare surrounding normal tissue.
• Intensity modulated radiation therapy (IMRT) is a form of 3D-CRT that further modifies the radiation by varying the intensity of each radiation beam. Doctors are still studying IMRT for the treatment of some types of breast cancer. Talk to your radiation oncologist for more information.
• More about external beam radiation therapy