Radiation Therapy

Radiation therapy is the use of high energy X-rays to kill cancer cells.

Radiation therapy is used to target tumors in specific locations. By delivering radiation to the tumor’s exact location, doctors hope to shrink its size. Sometimes, radiation takes place before surgery or chemotherapy is given to make the tumor small enough to remove, and other times, radiation takes place without the need for surgery.

Radiation therapy works by destroying or damaging rapidly growing cells, such as cancer cells. It damages cells only in the area of the body where the radiation is given. Unlike chemotherapy, radiation does not cause cell damage throughout the body. It can, however, damage healthy cells in the area being irradiated, but normal cells are better able to repair themselves.

Is Radiation Therapy Safe?

Radiation has been used successfully to treat patients for more than 100 years. In that time, many advances have been made to ensure that radiation therapy is safe and effective.

Before your child begins receiving radiation therapy, your radiation oncology team will carefully tailor their plan to make sure he or she receives safe and accurate treatment. Treatment will be carefully planned to target the cancer while avoiding healthy organs in the area. Special computers are also used to monitor and double-check the treatment machines to make sure the proper treatment is given. Radiation therapy will not make your child radioactive after treatment.

Delivering Radiation Therapy

Radiation therapy can be delivered in two ways, externally and internally. The majority of pediatric cancers are treated with external radiation.

During external beam radiation therapy, radiation beams come out of a machine called a linear accelerator. The beams are aimed at the tumor (either where it is or where it was before surgery and/or chemotherapy). You don’t see it, feel it, or taste it; it is completely invisible.

If your child needs to receive radiation, the radiation field (area) will be measured precisely and marked on your child’s body. This process is called “simulation.” Do not wash off the markings until after the radiation treatments are finished.

To minimize side effects, treatments are typically given five days a week, Monday through Friday, for a number of weeks. This allows enough radiation to get into the body to kill the cancer while giving healthy cells time to recover.

Radiation Therapy Team

You will meet many people during your child’s course of radiation treatments. A radiation oncologist, a doctor who specializes in treating cancer with radiation, leads the radiation team.

Radiation Oncologists

Radiation oncologists are the doctors who will oversee your child’s radiation therapy treatments. You will meet the radiation oncologist at the initial visit, and she/he will also see your child throughout the course of treatment to monitor and take care of any side effects. In addition to working with all the members of the radiation therapy team, your child’s radiation oncologist works very closely with the other doctors taking care of your child.

Radiation Oncology Nurses

Radiation oncology nurses work with the radiation oncologist and all other members of the treatment team taking care of your child. They will help your child with anything that comes up during the course of treatment. You will see the nurse as often as your child needs during treatment.

Radiation Therapists

Radiation therapists are the people who actually give the daily radiation treatment. They do so under the doctor’s prescription and supervision. They maintain daily records and regularly check the treatment machines to make sure they are working properly. These are the people at the radiation machinewho you will see every day.

Medical Physicists and Dosimetrists

Medical physicists and dosimetrists are responsible for developing radiation plans according to what your child’s doctor prescribes. Using computers, they develop treatment plans that can best destroy the tumor while sparing the healthy tissue.

Other Healthcare Professionals

You may work with a number of other healthcare professionals while undergoing radiation therapy. These specialists ensure that all of your child’s physical and psychological needs are met during treatment. They may include social workers, nutritionists, and physical therapists.

Radiation Therapy: During Treatment

Meeting with a Radiation Oncologist: If radiation therapy is part of your child’s treatment plan, you will first meet with a radiation oncologist. Your radiation oncologist will discuss the role radiation has in treatment and answer your questions. You will also meet the nurses who will help during treatment.

Simulation: To be most effective, radiation therapy must be aimed precisely at the same spot every time treatment is given. Simulation is the process of measuring your child’s body and marking the skin to help direct the beams of radiation safely and exactly to the intended locations.

Your radiation oncologist and radiation therapist will place your child on the simulation machine in the exact position that will be used during the actual treatment. Depending on what area of the body is going to be treated, simulation may include an immobilization device to ensure that your child remains in the same position every day during the entire treatment.

Treatment Planning: Once the simulation is finished, the radiation oncologist and other members of the treatment team review the information obtained during simulation along with previous medical tests to develop a treatment plan. The doctor will write a prescription that outlines exactly how much radiation is to be given and where. The complexity of the treatment plan dictates how soon after simulation that treatment will begin. Not all cancers are treated with the same amount of radiation; the duration of treatment is based on the tumor type and sometimes, the age of the child.

First Day: Before the first dose of radiation is given, the Radiation Oncology Unit will take treatment verification films (also called beam films or port films). These verify that the area being treated is in fact the exact area the doctor planned. These films need to be approved by the doctor before the first dose of radiation is given.

Daily Treatments: Every day, the radiation therapists will assure correct position, including use of the immobilization device if that is a part of treatment. Once correct placement is assured, the therapists will leave the room and go to the control area to closely monitor your child on a television screen. There is a microphone in the treatment room so your child can always talk with the therapists. The machine can be stopped at any time if your child is feeling sick or uncomfortable. Each session is painless; you don’t see it, taste it, or smell it. It is just like getting an X-ray. The machine might make noises during treatment that sound like clicking, knocking or whirring; this is normal.

Your child will be on the treatment table for 10-30 minutes; most of this time is spent setting up. Treatments are usually scheduled five days a week, Monday through Friday, and continue for one to 10 weeks depending on the type of cancer being treated.

Weekly Status Checks: Your radiation oncologist and nurse will see your child regularly during treatment to follow progress. Be sure to share any questions or concerns that you or your child may have during these visits or any time during treatment. They will evaluate whether your child is having any side effects and recommend treatments for those side effects (such as medication). As treatment progresses, your doctor may make changes in the schedule or treatment plan depending on response or reaction to the therapy.

Your radiation therapy team may also meet on a regular basis with other healthcare professionals to review your child’s case. This will ensure that treatment is proceeding as planned. During these sessions, all members of the team discuss progress as well as any concerns.

Weekly Port/Beam Films: To make sure the radiation beams are going exactly where they are designed to go throughout the course of treatment, once a week, the therapists will take port or beam films for the radiation oncologist to approve. These are the same type of films that were taken on the first day. Your radiation oncologist must approve these films in order to continue radiation. Your child may be on the table for a few more minutes than usual on the day of port/beam films. These films do not show the tumor’s response to radiation.

Follow Up: Your radiation oncologist will continue to work closely with the other team of doctors taking care of your child to make sure recovery is proceeding normally.

Tips for Parents

If possible, visit the radiation center with your child prior to the first treatment so you and your child will know what to expect. Some centers will let the child “ride” on the table and feel the laser beams so it will not be scary.

  • Review the radiation therapy plan with your doctor, including all potential side effects.
  • Discuss what can be done to prevent or treat side effects.
  • Understand the tests that will be done to monitor side effects.
  • Remember that you are the expert on your child. Notify the healthcare team of any changes you notice or concerns you may have.


Side Effects

Side effects from radiation therapy happen because radiation beams have to pass through normal, healthy cells and cause damage to them while treating the cancer. Although these normal cells will repair themselves in the longrun, in the shortrun this damage causes side effects. Side effects usually begin by the second or third week of treatment and may last for several weeks after the final radiation treatment. In rare instances, serious side effects develop after radiation therapy is finished.

The most common side effect, regardless of the area treated, is fatigue. The fatigue your child may experience is usually not very severe, and children can often continue all or some of their normal daily activities. Another side effect is decreased blood counts. If a large enough area is treated, the production of blood cells can be decreased. The radiation oncologist will monitor your child’s blood counts.

Skin changes are also common and are called radiation dermatitis. Treat the skin that is exposed to radiation with extra care. The skin in the area receiving treatment may become red and sensitive, similar to sunburn. Radiation can also cause hair loss in the area being treated. The radiation oncology nurse will review specific instructions for caring for your child’s skin with you. Some guidelines include:

  • Clean the skin daily with warm water and a mild soap recommended by your nurse.
  • Avoid using any lotions, perfumes, deodorants or powders in the treatment area unless approved by your doctor or nurse. Try not to use products containing alcohol and perfumes.
  • Avoid putting anything hot or cold on the treated skin. This includes heating pads and ice packs.
  • Stay out of the sun. If you must spend time outdoors, wear a hat or clothing to protect your skin. After treatment, use sunscreen with an SPF of at least 15.
  • Other side effects from radiation therapy happen in the body part through which the beam passes. Not all of these occur in every child; the severity of side effects also depends on the dose of radiation given (the number of treatments prescribed as necessary).


Radiation to the Brain

  • Ear pain/inflammation
  • Fatigue
  • Hair loss—Hair usually grows back 2-4 months after the treatment is completed; however the color and texture may be different.
  • Mild headache
  • Nausea/vomiting— Radiation can cause nausea or vomiting by stimulating the vomiting center in the brain. Medication can be given prior to radiation sessions that will help prevent this symptom.
  • Skin changes


Radiation to the Head and Neck

  • Change in taste
  • Difficult and painful swallowing
  • Dry mouth
  • Fatigue
  • Hair loss (upper neck/low posterior scalp)
  • Mouth sores
  • Skin changes
  • Sore throat


Radiation to the Chest

  • Chest pain/discomfort
  • Cough
  • Difficult and painful swallowing
  • Fatigue
  • Shortness of breath
  • Skin changes


Radiation to the Abdomen

  • Abdominal discomfort/cramping
  • Difficulty eating
  • Fatigue
  • Nausea/vomiting—Radiation can cause nausea or vomiting through direct irritation to the stomach lining. Medication can be given prior to radiation sessions to help prevent this symptom.
  • Skin changes


Radiation to the Pelvis

  • Cramping
  • Fatigue
  • Loose stools/diarrhea
  • Painful/frequent urination
  • Skin changes


Radiation to the Extremities

  • Fatigue
  • Skin changes


Long-term Effects of Radiation Therapy

Despite monitoring the effects of radiation therapy very closely, some long-term effects (also called late effects) can occur because of cell damage. These late effects may not be known until years after therapy is completed. Therefore, it is important that every patient be followed throughout his or her life by a physician who is aware of the late effects of cancer treatment.

A number of factors influence a child’s risk of developing late effects from radiation therapy.

  • Body part treated
  • Dosage of radiation
  • Age of the child at treatment


Below is a list of potential late effects related to radiation therapy. For more information about individual side effects, click on the link or go to the Late Effects section of this website.

General Late Effects


Radiation to the Brain


Radiation to the Head or Neck


Radiation to the Chest


Radiation to the Abdomen


Radiation to the Pelvis


Radiation to the Extremities