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

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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 destroy cancer, while sparing as much normal tissue as possible. The radiation oncologist will determine how many treatments 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 after it has spread. In some cases, once cancer has spread, radiation is no longer a cure. However, the treatments can help resolve problems that the cancer may be causing, including pain and weakness.

Radiation is most often given over a number of sessions. In select scenarios, single doses of focused radiation may be of benefit. Re-irradiation of previously irradiated areas increases the risk of normal brain tissue being destroyed. Your radiation oncologist should carefully consider these risks when discussing treatment options with you.


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. By comparison, brachytherapy delivers radiation directly to the cancer using a radioactive implant inside the body.

This treatment has been used with some success in the management of brain tumors. However, the tumor generally needs to be an inch or less in diameter. Ask your radiation oncologist if it is appropriate for you.

Stereotactic Radiosurgery

Stereotactic radiosurgery involves the delivery of 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.

When to Contact Your Doctor

Call your doctor if you:

  • Experience any change in mental abilities, coordination, or physical abilities such as vision or alertness
  • Develop any other side effects from the treatment
  • Develop new or unusual symptoms
  • Have red, blistered, or swollen skin