Radiation therapy (also called radiotherapy) uses high-energy rays to kill cancer cells. It affects cells only in the treated area.

You may receive external radiation. This is the most common type of radiation therapy for lung cancer. The radiation comes from a large machine outside your body. Most people go to a hospital or clinic for treatment. Treatments are usually 5 days a week for several weeks.

Another type of radiation therapy is internal radiation (brachytherapy). Internal radiation is seldom used for people with lung cancer. The radiation comes from a seed, wire, or another device put inside your body.

Educational information provided by The National Cancer Institute (NCI) Internet site.