Frequently Asked Questions
How does the Gamma Knife® work?
The Gamma Knife Perfexion™ precisely focuses 192 beams of gamma radiation on a specific target area of the brain, with each beam originating from a slightly different point. Highly sophisticated computer software is used to determine the size, location and shape of the area to be treated. Only at the point where all 192 beams cross is enough radiation delivered to affect the diseased tissue, while sparing surrounding tissue.
How is it that the beams don’t damage all the other areas that they pass through?
Each individual radiation beam is too weak to harm the brain tissue it passes through. The treatment occurs only at the spot in the brain where all the beams meet. With the help of a computer, this spot can be accurately plotted to within a fraction of a millimeter.
What makes the Gamma Knife treatment superior to other treatments?
It is precise. Its effects on surrounding brain and other critical neural and vascular structures are minimized. It is safe — the design of the Department of Neurosurgery’s Gamma Knife unit meets the rigorous standards for safety and efficacy set by the U.S. Nuclear Regulatory commission and patients do not face the risks associated with open-skull procedures or general anesthesia. The Gamma Knife Perfexion is also highly effective — its success rate is unprecedented.
Who can be treated with the Gamma Knife?
This noninvasive technology treats patients with abnormalities that are located within the brain or that are too close to delicate structures and blood vessels (though it is most effective on targets less than four centimeters in size). Almost a third of all the patients treated with the Gamma Knife since 1968 have sought relief from blood vessel problems (i.e. AVMs). Nearly two-thirds were treated for brain tumors, including cancer, glial tumors and rarer types of tumors. A small percentage sought treatment to relieve functional disorders like unmanageable pain, trigeminal neuralgia, Parkinson’s disease and epilepsy.
How can brain surgery be performed without incisions?
Instead of accessing the brain through incision(s), surgeons irradiate the brain abnormality with beams of gamma radiation that pass through the skull and brain tissue and treat only the designated area.
How long does the procedure take?
The procedure usually includes multiple doses that are delivered one after the other, all on the same day. The number of minutes that each radiation dose lasts is determined during dose planning and is dependent upon the size and number of areas to be targeted. There is typically no need for repeat treatments.
How is it I can have brain surgery and still return home the same day?
The lengthy hospital stay and recovery time required by traditional brain surgery has been eliminated by the Gamma Knife procedure. Since it requires no incisions and is performed under conscious sedation, the risks of infections and adverse reactions to general anesthesia are eliminated, as is recovery time. Additionally, unlike traditional brain surgery where there is a chance of damaging healthy brain tissue as the doctors make their way to the diseased area, the Gamma Knife procedure does not damage surrounding tissue — so patients do not need to be monitored for this possible complication either.
How long until I can return to my normal routine?
Patients are usually able to return to their former activities without discomfort or restrictions within 24 hours of the procedure.
Will I feel any pain during the procedure?
The procedure is relatively painless. A local anesthetic is injected in the four areas where the necessary head frame is attached to your head with mounting pins. This is very similar to how a dentist numbs your mouth when you have a cavity filled. You’ll feel slight pressure during the head frame application, but this sensation only lasts a few minutes and usually goes away when the head frame is in place. When your treatment is completed, the frame will be removed and an antibiotic ointment will be applied to the pin sites over which gauze will be placed followed by a head bandage. On rare occasions, there may be bleeding at a pin site which does not stop with pressure from the gauze. If this occurs, your doctor will use a stitch to close the pin site.
Why is it called the Gamma Knife if there are no incisions made?
The individual beams of gamma radiation are not strong enough to damage any tissue as they travel through the skull to the treatment site. At the site, the beams join together precisely to act in the same way a surgical “knife” would to treat the abnormality.
Will I lose my hair as a result of the procedure?
Because only the target tissue is irradiated, sparing the surrounding brain, hair loss is eliminated, unless the lesian is close to the surface. Then a patch of hair loss is possible.
Am I awake during the procedure?
Yes. You lie awake on your back during the procedure much like you would for an MRI or a CAT scan. A local anesthetic is given to you to numb the areas where the necessary head frame needs to be attached to your head.
Will there be/what are the side effects?
Generally you’ll experience no immediate side effects from the Gamma Knife procedure other than a mild headache or nausea. Should this occur, your nurse can give you medications ordered by your doctor to relieve the headache or nausea. Side effects are rare because only the abnormality is targeted; the surrounding brain tissue receives a minimal dose of radiation.
What kinds of doctors will be involved with my procedure?
A multidisciplinary team of neurological surgeons, radiation oncologists, medical physicists, radiologists, nurses, computer specialists, and physician assistants unite to provide you with comprehensive, advanced care before, during and after the procedure.
Is this new technology proven safe?
To date, more than 350,000 patients worldwide have been safely and effectively treated with the Gamma Knife for malignant and benign brain tumors, vascular abnormalities and functional disorders. Among the medical community, the Gamma Knife is regarded as the “gold standard” in delivering stereotactic radiosurgery.
Will my insurance cover the procedure?
The Gamma Knife is recognized and covered by most insurance plans. Consult your plan coordinator for specific details.