Gamma Knife

Gamma Knife helps you get back to life sooner. 

Gamma knife therapy

How Gamma Knife works

Gamma Knife is a non-invasive alternative option to brain surgery and radiation, where brain tumors are treated without a knife, drugs or weeks of radiation. Gamma Knife uses up to 200 focused beams of radiation to control tumors without harming surrounding health brain tissue. The treatment takes just one day and has no immediate side effects, so you can get back to your life sooner.

More than 70,000 people per year undergo this highly effective form of stereotactic radiosurgery. In fact, Gamma Knife is supported by two decades of clinical research for the treatment of cancerous and non-cancerous brain tumors and brain metastases.

It has been used to treat tumors that were previously inoperable.

Visit Legacy Gamma Knife Center

Legacy Good Samaritan Medical Center 
Good Samaritan Building 3 
1130 N.W. 22nd Ave. 
Portland, OR 97210 
1-800-889-2607, press 1 (toll free)

What to expect during treatment

Since Gamma Knife is non-surgical, the procedure is done without opening the skull. The actual procedure typically lasts 15 to 40 minutes and is performed with local anesthesia. A Legacy Cancer Institute radiation oncologist and neurosurgeon direct the treatment.

  • The procedure: We fit you with a stereotactic frame, which prevents your head from moving during treatment. Once the frame is in place, we calculate precise settings. You rest on a special couch that moves into the Gamma Knife machine.

  • No pain or side effects: You feel virtually no pain or immediate side effects. The treatment works over time, dissolving or shrinking the tumors gradually and eventually making them disappear. Other tumors do not grow any more. The time needed for the treatment to work varies with the type, size and location of the tumor.

  • Lower expenses: Gamma Knife helps people avoid many of the costs associated with surgery, because the treatment does not require a long hospital stay or recovery.

When you are treated at Legacy Gamma Knife Center, you are cared for by specialists who develop an individual treatment plan to help manage your symptoms and other challenges of cancer treatment.

Is Gamma Knife right for you

Treatment with the Gamma Knife may be an option if you have a hard-to-reach brain tumor, metastatic brain tumors or a number of non-cancerous brain tumors or conditions.

Among the people suited for Gamma Knife are those:

  • With a brain tumor that can’t be reached with standard radiation or surgery

  • Who are not healthy or young enough for surgery

  • Who prefer a less-invasive treatment

In some cases, Gamma Knife is the only possible approach for treatment. It may also be used along with standard radiation treatment or neurosurgery.

What happens next

Many cancer treatments can cause challenging side effects. Your cancer team is dedicated to helping you manage these issues in the best ways possible.


Gamma Knife treatment is less likely to damage nearby healthy tissue than other radiation therapies, but there can be side effects. Brain swelling may occur, but often goes away without treatment. Medicine can be prescribed and, in rare cases, surgery is used to treat the swelling. Spots where the frame was attached to the scalp might be red and sensitive after treatment, but that goes away with time.

To see how well your treatment is working, some of the tests used to diagnose and stage your cancer may be repeated. Your Legacy Cancer Institute doctor uses these tests to decide whether to stop, change or continue treatment based on the results. The tests can also determine if cancer has returned.

Whenever possible, we work to stop cancer. But when we can’t, we can often control it for a better quality of life, often called palliative care.

Working together for you

Our cancer experts work together with a common goal: delivering the right care for you.

A range of specialists collaborate regularly in meetings called tumor boards to discuss the best plan for your care. Your treatment plan is made just for you, depending on your general health, your age, your particular cancer and its growth.

More support

You are not alone. Legacy offers support throughout your cancer journey, as well as care for your emotional, social and spiritual needs.

Nurse navigators
Legacy Cancer Healing Center 
Support groups and classes
Cancer rehabilitation 
Survivorship services

Visit Legacy Gamma Knife Center

Legacy Good Samaritan Medical Center 
Good Samaritan Building 3 
1130 N.W. 22nd Ave. 
Portland, OR 97210 
1-800-889-2607, press 1 (toll free)