External Beam Radiation Therapy
External beam radiation therapy is a local treatment, meaning that the radiation is aimed only at a specific part of your body. For example, if you have lung cancer, you will get radiation to your chest only and not the rest of your body.
External beam radiation therapy comes from a machine that aims radiation at your cancer.
Radiation is sometimes given in smaller doses twice a day (hyperfractionated radiation therapy). Your doctor may prescribe this type of treatment if he or she feels that it will work better. Although side effects may be more severe, there may be fewer late side effects. Doctors are doing research to see which types of cancer are best treated this way.
If you agree to have external beam radiation therapy, you will be scheduled for a treatment planning session called a simulation. At this time:
- A radiation oncologist and radiation therapist will define your treatment area (also called a treatment port or treatment field). This refers to the places in your body that will get radiation. You will be asked to lie very still while x-rays or scans are taken to define the treatment area.
- The radiation therapist will then put small marks (tattoos or dots of colored ink) on your skin to mark the treatment area. You will need these marks throughout the course of radiation therapy. The radiation therapist will use them each day to make sure you are in the correct position. Tattoos are about the size of a freckle and will remain on your skin for the rest of your life. Ink markings will fade over time. Be careful not to remove them and make sure to tell the radiation therapist if they fade or lose color.
- You may need a body mold. This is a plastic or plaster form that helps keep you from moving during treatment. It also helps make sure that you are in the exact same position each day of treatment.
- If you are getting radiation to the head, you may need a mask. The mask has air holes, and holes can be cut for your eyes, nose, and mouth. It attaches to the table where you will lie to receive your treatments. The mask helps keep your head from moving so that you are in the exact same position for each treatment.
If you are getting radiation to the head, you may need a mask.
If the body mold or mask makes you feel anxious, see "Your Feelings During Radiation Therapy" for ways to relax during treatment.
- You may be asked to change into a hospital gown or robe.
- You will go to a treatment room where you will receive radiation.
- Depending on where your cancer is, you will either sit in a chair or lie down on a treatment table. The radiation therapist will use your body mold and skin marks to help you get into position.
- You may see colored lights pointed at your skin marks. These lights are harmless and help the therapist position you for treatment each day.
- You will need to stay very still so the radiation goes to the exact same place each time. You can breathe as you always do and do not have to hold your breath.
- Bring something to read or do while in the waiting room.
- Ask if you can listen to music or books on tape.
- Meditate, breathe deeply, use imagery, or find other ways to relax. To learn more about ways to relax, see Facing Forward: Life After Cancer Treatment, a book from the National Cancer Institute. You can order a free copy at www.cancer.gov/publications or 1-800-4-CANCER.