Definition

Radiation therapy (RT) treats cancer and other diseases. It uses high-energy particles to break the DNA in the cancer cells. The cells can’t grow or divide when the DNA is damaged

There are 2 main types of RT:

• External—radiation is delivered by a machine that aims particles at the cells from outside the body
• Internal —radioactive materials are placed in the body near the cells

In certain cases, your doctor may advise using both. It is also used with surgery, chemotherapy, and therapy to spark the immune system to fight infection.

This fact sheet will focus on external RT.

Reasons for Procedure

RT may be done to:

• Control the growth or spread of cancer
• Try to cure your cancer
• Reduce pain or other cancer symptoms

RT is used to treat:

• Solid tumors, such as prostate cancer, breast cancer, and head and neck cancers
• Lymphomas and leukemia

Possible Complications

External RT does not cause your body to become radioactive. It can cause side effects. The radiation harms healthy cells and cancer cells. Here are some common side effects:

• Fatigue
• Skin changes (redness, irritation)
• Reduced white blood cell count
• Hair loss
• Nausea, vomiting, or diarrhea
• Lack of hunger

Talk to your doctor about the side effects you may have.

Factors that may raise the risk of problems include:

• Previous RT
• If you have had systemic lupus erythematosus, scleroderma, or dermatomyositis

A woman who is pregnant or could be pregnant should avoid being around radiation. It could harm the growing fetus.

What to Expect

Description of the Procedure

You will be positioned on a table or chair. The therapist will leave the room and enter a control room. The machine will send radiation to the sites on your body. The most common sources of RT are x-rays, electron beams, and cobalt-60 gamma rays.

You must remain still. The therapist can see you on a screen. You can talk with the therapist if you feel sick.

External Radiation of a Tumor Copyright © Nucleus Medical Media, Inc.

Call Your Doctor

Call your doctor if you have:

• Signs of infection, such as fever and chills
• Diarrhea or loss of hunger
• Weight loss without a known cause
• Pain or burning with urination
• Frequent urination
• New or unusual swelling or lumps
• Nausea and vomiting
• Pain that doesn't go away with the medicines you were given
• Changes in skin, such as bruises, rashes, discharge, or bleeding
• Cough, problems breathing, or chest pain
• New or unexpected symptoms

If you think you have an emergency, call for emergency medical services right away.