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: external, given from outside the body 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 swallowedor 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: National Cancer Institute CureSearch The American Society for Radiation Oncology Back to Articles Related Articles Cancer Center Visit our Cancer Center for teens to get information and advice on treating and coping with cancer. Read More Cancer Basics Get the basics on cancer and cancer treatments in this article. Read More Cancer: Readjusting to Home and School If you've just finished a long hospital stay, you may have questions about reconnecting with friends and family. Get answers in this article for teens. Read More Dealing With Cancer It's unusual for teens to have cancer, but it can happen. The good news is that most will survive and return to their everyday lives. Learn about how to cope if you or someone you know has cancer. Read More Can I Have Children After Cancer Treatments? When chemotherapy and other treatments attack cancer cells, they can affect some of the body's healthy cells too. As a teen, you'll want to know what this can mean to your fertility. Read More Chemotherapy Chemotherapy (chemo) is treatment with medicines that stop the growth of cancer cells. Find out how chemo works and what to expect when getting treatment. Read More Steroids and Cancer Treatment If your doctor prescribed steroids as part of your treatment for an illness, don't worry. It's not the illegal, doping scandal kind of steroid. Get the details in this article for teens. Read More Melanoma Melanoma is different from other skin cancers because it can spread if it's not caught early. Find out how to lower your risk of getting melanoma and how doctors treat it. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.