There are a several types of radiation therapy that can be used to treat cancer. These include:

External Beam Radiation Therapy

In external beam ]]>radiation therapy]]>, radiation is produced by a machine called a linear accelerator. Short bursts of x-rays are fired from the machine at your cancer. The radiation oncologist designs a plan to shape the radiation beam so that it treats the cancer and as little normal tissue as possible.

Radiation of a Tumor

Diagram of modified radical mastectomy
© 2009 Nucleus Medical Art, Inc.

Like ]]>chemotherapy]]>, the side effects from radiation result from injury to the normal tissues. There are many new ways that the radiation oncologist can customize your treatment to try and kill as much cancer, while sparing as much normal tissue as possible. The radiation oncologist will determine how many treatments (fractions) you will receive. They most often occur once a day, often with no treatments on the weekends. Treatments may go on for a number of consecutive weeks.

Radiation therapy can be given to treat cancer at its initial site or once it has spread. In some cases, once cancer has spread, radiation is no longer curative. However, the treatments can help resolve problems that the cancer may be causing, including pain and weakness.

Radiation is most often given in a fractionated (over a number of sessions) manner. However, in select scenarios single doses of focused radiation (stereotactic radiosurgery) may be of benefit. Re-irradiation of previously irradiated areas increases the risk of radiation necrosis (dying off of good brain tissue). Your radiation oncologist should carefully consider these risks when discussing treatment options with you.


“Brachy” means “short,” and brachytherapy uses radiation therapy at very short distances. When you receive external beam radiotherapy, the radiation comes out of a machine located about 40 inches above you. Brachytherapy, on the other hand, delivers radiation directly to the cancer via a radioactive implant from inside the body.

This treatment has been used with some success in the management of brain tumors. However, the tumor generally needs to be very small (an inch or less in diameter). Brachytherapy, though feasible in some circumstances, has never been shown to be superior to external beam radiotherapy in the management of brain tumors. This special type of treatment is used at many centers in the US. It often does not replace the role of fractionated external beam radiation in most brain tumors. Ask your radiation oncologist if it is appropriate for you.

Stereotactic Radiosurgery

In some research and private treatment centers, stereotactic radiosurgery is available. This type of procedure is performed by various types of equipment, such as ]]>Gamma Knife]]>, Cyberknife, Trilogy, among others. This involves the delivery of very intense, carefully focused radiation to the tumor site. Typically, this procedure takes several hours. It is not available everywhere and is not appropriate for every type of tumor. It is most often appropriate for metastatic brain tumors. In some cases, the insurance company does not pay for the cost of stereotactic radiosurgery.

When to Contact Your Doctor

Call your doctor if you:

  • Experience any change in mental abilities, coordination, or physical abilities (including vision or alertness)
  • Develop any other side effects from the treatment
  • Develop new or unusual symptoms
  • Your skin is red, blistered, or swollen