Home > Encyclopedia of Cancer > Radiation Therapy

Definition

Radiation therapy, sometimes called radiotherapy, x-ray therapy radiation treatment, cobalt therapy, electron beam therapy, or irradiation uses high energy, penetrating waves or particles such as x rays, gamma rays, proton rays, or neutron rays to destroy cancer cells or keep them from reproducing.

Purpose

The purpose of radiation therapy is to kill or damage cancer cells. Radiation therapy is a common form of cancer therapy. It is used in more than half of all cancer cases. Radiation therapy can be used:

• alone to kill cancer
• before surgery to shrink a tumor and make it easier to remove
• during surgery to kill cancer cells that may remain in surrounding tissue after the surgery (called intraoperative radiation)
• after surgery...