Radiation Therapy
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Radiation Therapy

Reviewed by: Eric S. Sandler, MD

What Is Radiation Therapy?

Radiation therapy is a treatment for cancer. It works by preventing cancer cells from growing and by destroying them.

The high-energy radiation used comes from:

  • X-rays
  • gamma rays
  • fast-moving tiny particles (called particle or proton beam therapy)

Radiation therapy is also called radiotherapy, irradiation, or X-ray therapy.

How Does Radiation Therapy Work?

Radiation therapy can be either:

  1. external, given from outside the body
  2. internal, done inside the body

External radiation therapy uses a large machine and special equipment to carefully aim the right amount of radiation at cancerous tumors.

With internal radiation therapy, doctors inject or implant a radioactive substance into the area with the tumor or cancer cells. In some cases, the patient swallows the material.

Some people may need both external radiation and internal radiation.

Besides killing cancer cells and shrinking tumors, radiation therapy also can harm normal cells. Normal cells are more likely to recover from its effects. The health care team will carefully check a teen's radiation doses to protect healthy tissue.

What Happens During External Radiation Therapy?

For external radiation therapy, teens usually go to the hospital or treatment center 4 to 5 days a week for several weeks. They'll get small daily doses of radiation, which helps protect the normal cells from damage. The weekend breaks help the cells recover from the radiation.

If you get radiation therapy, the radiation therapist will mark an area on your skin with ink. This "tattoo" helps show the treatment area.

Most of the time that you'll spend on the radiation treatment table involves positioning. The treatment itself takes only minutes. When you're in the right position:

  • The radiation therapist leaves the room.
  • The machine delivers the right amount of radiation to kill the cells.

Parents aren't allowed in the treatment room, but can wait nearby for you during therapy.

What Happens During Internal Radiation Therapy?

Most teens who get internal radiation treatment stay in the hospital for several days. The radioactive material is:

  • put into the tumor
  • swallowed
    or
  • injected into the bloodstream

Doctors might do a minor surgery using anesthesia to place the material (for example, when treatment is in the uterus, esophagus, or airway).

Internal radiation therapy is also called brachytherapy, interstitial therapy, or implant therapy.

Can I Be Around Other People If I Get Radiation?

Teens may wonder whether they can touch or hug others during and after therapy.

  • Teens who get external radiation therapy have no restrictions on contact with family members.
  • Teens who get internal radiation therapy may have some restrictions. Radiation in the implant can send high-energy rays outside the patient's body. To protect others from exposure, the patient will be in a private room. Health care team members enter for short periods and work quickly to provide care. Visiting times might be brief, and young kids, pregnant women, and others might not be allowed into the room.

Does Radiation Therapy Cause Side Effects?

Radiation can damage healthy cells. This damage can cause side effects such as skin problems, tiredness, and anemia. The type of side effects someone might get depends on the dose of radiation, whether it was internal or external, and the area treated.

Many patients have no side effects. When problems do happen:

  • Most will go away after radiation therapy ends.
  • They usually aren't serious.
  • Treatment can help control them.

What Else Should I Know?

Before your treatment, it may help to take a tour of the radiation department to see the radiation technologists and equipment so you can get familiar with them.

And you don't have to go it alone. The doctors, nurses, social workers, and other members of the cancer treatment team are there to help you before, during, and after cancer treatment.

You also can find information and support online at:

Reviewed by: Eric S. Sandler, MD
Date reviewed: December 2018