Radiation therapy is a method used to kill tumor cells. It tends to work best when used with other methods such as surgery and chemotherapy. It may be used after surgery to kill tumor cells left behind. Sometimes, it’s used to ease problems caused by the tumor.

The types used are:

External Beam Radiation

This type is made by a machine outside the body. Short bursts are aimed at the tumor. It's most often given over many sessions. For some, single doses that are more focused may be better.

The craniospinal type treats the whole brain and spinal cord. It’s used when there’s been a spread to nearby layers or fluid.

Radiation of a Tumor
Diagram of modified radical mastectomy

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The method may be as:

  • 3D conformal radiation therapy (3D-CRT)—The brain is mapped. Then, beams are focused from many angles.
  • Intensity modulated radiation therapy (IMRT)—A machine aims beams while rotating around you.
  • Conformal proton beam radiation therapy—Proton beams are used instead of x-rays. It allows for higher doses to be used. This is because it causes less damage to nearby healthy tissue.

Internal Radiation

Radioactive material is placed in or near the tumor. This tends to work better when they are smaller.

Stereotactic Radiosurgery

This method aims beams to a very focused place. As a result, higher doses can be used over less time.

It’s used more when cancer has spread from other sites in the body. This may not be offered where you live.

Side Effects and Management

You may have problems with:

  • Thought or memory
  • Feeling tired
  • Headaches
  • Nausea or vomiting

There are many ways to fix these problems. Common methods are medicines and lifestyle changes. In some cases, the dose may be changed. Call your doctor as soon as you notice any problems.


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Last reviewed May 2018 by EBSCO Medical Review Board Mohei Abouzied, MD, FACP  Last Updated: 8/9/2018