If you have a tumor or other abnormality in your brain, your doctor may suggest Gamma Knife® radiosurgery.
Despite its name, the Gamma Knife procedure is not surgery. It is a painless treatment that uses radiation beams to target tumors and lesions.
Gamma Knife is an advanced treatment for brain tumors, movement disorders, and other brain conditions.
For nearly four decades, UPMC has been a leader in Gamma Knife treatment. UPMC installed the first Gamma Knife in North America in 1987 and has helped pioneer each advancement in the technology. More than 19,000 patients have had Gamma Knife radiosurgery at UPMC, with excellent outcomes.
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Gamma Knife radiosurgery is a noninvasive, highly precise radiation treatment for brain tumors and other brain conditions. It is a type of stereotactic radiosurgery (SRS) that uses targeted radiation beams to treat brain conditions.
Gamma Knife treatment is not surgery; there are no actual knives or long incisions involved. Instead, Gamma Knife is a radiation treatment. Highly focused gamma rays target the affected part of the brain while minimizing exposure to surrounding healthy tissue.
The goal of Gamma Knife is to inactivate brain tumors and other brain conditions. Because it does not typically require incisions or general anesthesia, it may be a safer alternative to open surgery. It can also target deep brain tumors, arteriovenous malformations (AVMs), and other conditions that may not otherwise be operable.
Gamma Knife is a precise, effective, and safe treatment. It targets a specific area of your brain and prevents damage to surrounding tissue. The amount of radiation can be customized for your condition. The goal of treatment is to destroy AVMs and stop tumor growth, which also sometimes shrinks tumors.
At an advanced center like UPMC, Gamma Knife is a common procedure for complicated brain tumors and conditions. UPMC performs about 600 Gamma Knife procedures each year and achieves excellent outcomes.
As a treatment, Gamma Knife radiosurgery can address brain tumors and other disabling, debilitating, or life-threatening brain conditions. It may cure certain conditions, lengthen your lifespan, and/or improve your quality of life.
Gamma Knife can provide a treatment option for tumors and conditions deep in the brain that may not otherwise be operable. It also can complement other surgical procedures by helping to treat any remaining tumor or lesion.
Gamma Knife is an extremely precise procedure with sub-millimeter accuracy. It is also noninvasive, meaning patients experience fewer complications and a shorter recovery time. The majority of patients are treated and are discharged home the same day.
Many factors play a role in determining whether you are a candidate for Gamma Knife treatment, including:
UPMC experts will evaluate your case using a multidisciplinary team approach. Our team includes experts in neurosurgery, radiation oncology, medical oncology, neuro-oncology, nursing, and other specialties. We discuss your case as a group to determine if you are a candidate for Gamma Knife or another treatment option.
You may experience some short-term side effects after Gamma Knife treatment, including:
Long-term complications of the procedure are rare but can include:
Talk to your doctor if you are concerned about complications of the procedure. These complications are rare and typically can be treated with medication if they occur.
You may need to stop eating and drinking by midnight the night before your Gamma Knife treatment. The nursing staff will give you specific instructions for your procedure.
Ask your doctor about any prescription drugs you take. They will tell you which medicines you can and cannot take on the day of your procedure.
The day of your treatment:
Before the treatment begins, your care team will obtain high-definition MRIs of your brain. The imaging will show the exact location, size, and shape of the tumor or other problem area, helping to ensure accuracy during the procedure. Additional testing may be needed on the day of the procedure, depending on your diagnosis.
The Gamma Knife procedure typically takes less than an hour. For more complex cases, it may last longer than an hour. Most patients go home on the same day of their procedure.
You will have an IV placed and can have medicine to help you relax if you need it. However, you will not typically receive general anesthesia — you will be awake throughout the procedure. The treatment itself is painless.
There are two options for Gamma Knife treatment: a frame-based procedure and a mask-based (frameless) procedure.
For the frame-based procedure, your team will fit you with a circular metal frame that holds your head in the right place. They will then attach the frame to your scalp and skull with small pins that puncture the skin. You will receive local anesthesia and moderate sedation by IV.
For the frameless procedure, your team will fit a specialized mask over your face. The mask is contoured to your face and helps you keep your head and face still during treatment. You will not typically need sedation or local anesthesia.
Both the frame and mask are specially designed to hold your head in place as the Gamma Knife system delivers precise radiation treatment.
During the procedure:
The treatment typically lasts less than an hour.
After treatment, your care team will remove the frame or mask that kept your head in place during the procedure. If you had the frame procedure, your team will bandage the areas where the pins were placed.
You will move to a recovery area where your care team will monitor you to ensure you recover well. You can eat or drink as soon as you are able. You may have a headache after the frame removal. If so, your care team will give you medicine to make you feel better.
You should be able to go home on the same day as your procedure. You will need someone to drive you home if receiving sedating medication.
You will receive instructions on how to care for yourself at home in the days after the procedure. If you had the frame procedure, we will give you instructions on caring for the sites where the pins were placed during the procedure.
Many patients can return to their normal daily routines the day after their Gamma Knife procedure. That includes work and other activities.
You may feel some side effects, such as fatigue, for several days after the procedure. Fatigue and other side effects are generally mild and go away soon.
You should experience a lessening of the symptoms related to your condition over time.
You will need follow-up imaging. Depending on your health issue, you may need just one Gamma Knife treatment or more sessions. Your doctor will provide more details.
Complications are rare after Gamma Knife treatment. However, you should call your doctor if you experience seizures or other unexplained symptoms.
Your life expectancy and overall prognosis after Gamma Knife radiosurgery depends on your health problem.
Potential results of Gamma Knife treatment for various conditions include:
Your doctor can give you more details about what to expect after the procedure.
Since 1987, UPMC has successfully performed more than 19,000 Gamma Knife treatments for patients with:
At UPMC, we have performed Gamma Knife radiosurgery on more than 1,500 patients with arteriovenous malformations. The treatment has destroyed 70% to 90% of AVMs within three years — delivering better outcomes than other treatment options.
We have also performed more than 1,600 Gamma Knife procedures on patients with acoustic neuroma — a tumor on the nerve connecting the inner ear to the brain that can cause deafness. The treatment prevented tumor growth in 97% of patients, and up to 80% kept their hearing in the long term.
UPMC has seen similar excellent outcomes for the other conditions treated with Gamma Knife.
UPMC installed the first North American Gamma Knife in 1987. Since then, we have introduced and pioneered multiple technological improvements.
Today, UPMC is a national and international leader in Gamma Knife treatment. We perform about 600 procedures each year with excellent outcomes. We are also a major teaching center for neurosurgeons, radiation oncologists, health physicists, and nurses from around the world.
We use a multidisciplinary team approach to treat each patient. Our team of neurosurgeons, medical oncologists, radiation oncologists, and neuro-oncologists meets frequently to discuss patients. Together, we manage each patient from diagnosis through treatment.
UPMC has two Gamma Knife units: the Gamma Knife Esprit and the Gamma Knife Icon. We are one of only a few hospitals worldwide with two Gamma Knife units.
The GK Esprit is the most state-of-the-art Gamma Knife unit available today. It uses artificial intelligence, advanced robotics, and other technological advancements.
Together, the advanced technology provided with the Icon and Esprit:
Since installing the first Gamma Knife at UPMC, we have performed more than 19,000 procedures. We have achieved excellent outcomes in tumor control, AVM obliteration, and more, with outstanding patient satisfaction.
By UPMC Editorial Staff. Last reviewed on 2025-03-19 by Costas G. Hadjipanayis, MD, PhD.
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