Treating Cancer in Children: Radiation Therapy

Radiation therapy helps your child fight against cancer. It uses high-energy X-rays to destroy cancer cells, so the treatment is strong and causes side effects. Read on to learn about radiation and how you can help your child cope with its side effects.

How Radiation Therapy Works

Boy is lying on table underneath radiation machine. His hospital gown is open to expose his chest. Healthcare provider is using electronic pad to prepare radiation machine.

Radiation kills cancer cells gradually, over time. The goal of treatment is to focus the radiation on cancer cells. But radiation can also damage or kill the normal, healthy cells near the tumor. These damaged normal cells often can repair themselves within a week.

Types of Radiation

Two types of radiation are used to treat childhood cancers:

  • External radiation. A machine sends high-energy X-rays from outside the body to where a tumor is located. The machine moves around the body, allowing the X-ray beams to enter the body at specific angles.

  • Intraoperative radiation therapy. During surgery, as much of the tumor as possible is removed. Then nearby organs are moved out of the way while a machine sends beams of high-energy X-rays directly to a tumor site. This type of radiation therapy is less common for children. Your health care team can tell you more if needed.

What to Expect

External radiation is most often used for children. Treatment depends on the type of cancer your child has and what his or her health care team decides is best for your child. Treatment is usually given on an outpatient basis. This means the child goes to the hospital to receive treatment and then goes home. There is no overnight stay in the hospital. The child may need to visit the hospital for radiation therapy 4 to 5 days a week for several weeks:

  • Before treatment, a practice run (called a simulation) occurs. During this session, your child lies down on an X-ray table. The exact areas of the body where the radiation beams will be focused are chosen and marked on your child’s skin. X-rays and CT scans may also be taken at this time.

  • During treatment, your child lies very still on a table. If your child cannot lie still, straps and pillows may be used to keep him or her from moving . Or, sedation (medication) may be given to keep your child calm during the procedure. The radiation machine moves around the child’s body, sending radiation beams to the appropriate areas.

The procedure is not painful and takes only a few minutes. Most of the rest of the time is spent making sure the child is properly positioned. Keep in mind that you will not be able to go into the room during treatment. But you may still be able to talk to your child during the treatment. Ask your child’s health care team any questions you have about radiation therapy.

Side Effects of Radiation

Side effects occur when normal cells are affected by radiation. Some side effects are short-term and go away soon after treatment ends. These can include fatigue, hair loss, and skin dryness or irritation. Other side effects are long-term and may last longer. Or, they may occur months or even years after treatment. These may include infertility or another cancer at a later time. The side effects your child may experience depend on the site where radiation is given. Ask your child’s doctor which side effects your child may have.


Call Your Child’s Health Care Provider 

Call your child’s health care provider right away if your child has any of the following:

  • In an infant under 3 months old, a temperature of 100.4°F (38°C) or higher

  • In a child 3 to 36 months, a rectal temperature of 102°F (39°C) or higher

  • In a child of any age who has a temperature of 103°F (39.4°C) or higher

  • A fever that lasts more than 24 hours in a child under 2 years old, or for 3 days in a child 2 years or older

  • If your child is receiving chemotherapy and may have neutropenia (low white blood cell count), any fever above 100.4°F (38°C) should be reported right away. 

  • Your child had a seizure caused by the fever

  • Chills

  • Ongoing fatigue

  • Trouble concentrating

  • Trouble breathing

  • Pain that doesn’t go away, especially if it’s always in the same place

  • A new or unusual lump, bump, or swelling

  • Dizziness or lightheadedness

  • Unusual rashes, bruises, or bleeding

  • Uncontrolled nausea and vomiting

  • Diarrhea that doesn’t improve over time

  • Skin breakdown or severe pain due to skin irritation

  • Any new or concerning symptom

Cancer Resources

To learn more and find support check out these resources:

  • American Cancer Society   

  • National Cancer Institute  

  • CancerNet