The Leksell Gamma Knife® is an effective, non-invasive alternative to traditional brain surgery exclusively designed for the treatment of malignant and benign tumors, vascular abnormalities and trigeminal neuralgia.
This highly sophisticated technology precisely directs focused radiation to specific targets in the brain. Typically performed in a single outpatient treatment session without general anesthesia, this proven technique helps patients avoid incision, scarring and long hospital stays while minimizing surgical complications.
Patients experience minimal pain and, in most cases, can resume their pre-treatment activities within a day or two after treatment. It is one of the most advanced techniques in the treatment of disorders affecting the brain and its adjacent structures.
Gamma Knife is a radiosurgery device that delivers 201 precisely focused gamma rays to the head using a three-dimensional targeting system. Gamma Knife technology has developed a highly successful record for treating conditions such as benign and metastatic brain tumors, head and skull base tumors, vascular malformations of the brain and trigeminal neuralgia.
Yale-New Haven Hospital Gamma Knife Center has the only stereotactic radiosurgical facility in Connecticut that is dedicated to treating brain or skull base disorders and is one of a very small number of institutions that offers this technology.
The Gamma Knife method:
- offers a noninvasive, bloodless neurosurgical procedure
- usually does not require general anesthesia or opening the head surgically
- is an excellent option for those who cannot tolerate medications or are poor candidates for open surgery (e.g. children, the elderly or patients with co-existent medical conditions)
- offers accurate targeting of lesions of different sizes, shapes and depth with little risk to surrounding healthy tissues
- has rapid recovery – most patients return home the same day after a brief observation period and can return to their regular activities without any precautions
- can be repeated safely after an interval of several weeks to months, if necessary
The Gamma Knife procedure can benefit patients who have:
- Benign tumors such as meningiomas, acoustic neuromas, pituitary adenomas and craniopharyngioma
- Some primary or recurrent malignant brain tumors such as astrocytomas or oligodendrogliomas
- Solitary and multiple brain metastases
- Head and skull base tumors such as nasopharyngeal carcinomas and ocular melanomas
- Arteriovenous malformations (AVMS)
- Trigeminal neuralgia
- Intractable pain secondary to cancer
In addition, Gamma Knife is used to treat pediatric patients with selected tumors or vascular lesions.
It is also being used as an investigational tool for certain forms of epilepsy and psychiatric disease.
Stereotactic radiosurgery is defined as the delivery of a single, high dose of radiation through the intact skull to a small and critically located intracranial volume.
The Gamma Knife tailored plan contains 201 cobalt-60 sources of approximately 30 curies each at time of loading. The sources are placed in a hemispherical array in the collimator helmet, a heavily shielded unit. With sub-millimeter positioning accuracy, the helmet focuses 201 radiation beams on a specific target point within the head. A high dose of radiation is delivered to the target, sparing the surrounding tissue. The complex-shaped lesions are treated by combining collimators of different sizes with selected beam blocking and weighting. Targeting is achieved by using a sophisticated computer planning system that ensures tight conformation of the dose.
The Gamma Knife has few moving parts, thereby eliminating many potential sources of inaccuracy and unreliability. Because the radiation fall-off is very steep outside the target area, the surrounding brain receives minimal radiation thereby minimizing harmful side effects to neighboring critical structures. Many of the risks of open surgery are eliminated with Gamma Knife radiosurgery. The treatment is particularly useful in patients with advanced age or in those patients with other illnesses where conventional surgery would pose an unacceptably high risk.
- requires no incisions and is performed under local anesthesia with mild sedative
- eliminates risk of infections and adverse reactions to general anesthesia
- patients experience minimal pain
- patients are able return to their pre-treatment activities without discomfort or restrictions
- hospitalization is minimized or not required
- only the target tissue receives significant radiation which:
- markedly reduces risk to the surrounding brain
- eliminates hair loss
- and minimizes nausea and epileptic seizures
The patient arrives at the Gamma Knife Center the morning of the procedure and is started on intravenous fluids after he or she has received a mild sedative. The surgeon then affixes the stereotactic frame to the patient’s head. With the frame on, the patient then undergoes the appropriate imaging studies (MRI, CT and/or angiography) to precisely localize the target tissue to be treated. While the patient rests, the treatment plan is developed by the neurosurgeon, radiation oncologist and physicist based on the imaging studies obtained using an advanced dedicated software system known as GammaPlan. This typically takes up to two hours to complete.
Once the individualized treatment plan is completed, the patient is placed on the Gamma Knife couch and the stereotactic frame is attached to the collimator helmet. After all stereotactic coordinates are double checked, the couch is moved into the unit by an electrical motor and treatment begins. While the patient is being irradiated, there is no noise and the patient feels no pain. Communication is maintained with the patient at all times by video cameras and an intercom, allowing the patient to freely communicate with the treatment team. Treatment time typically varies between 30 minutes to over three hours, depending on the complexity of the plan. At the conclusion of the treatment, the stereotactic frame is removed and the patient is observed for a brief period before being discharged.
Patients referred to the Yale-New Haven Hospital Gamma Knife Center will be evaluated by a team of specialists with extensive experience, including neurosurgeons, radiation oncologists and neuroradiologists. Candidates for the procedure are selected for treatment only after a thorough review of prior patient records and imaging studies.
The following is a brief sample of results achieved with some of the conditions that respond to Gamma Knife therapy:
Meningiomas — Compared to resection, which can result in up to 20 to 40 percent recurrence rate at 10 year follow-up, radiosurgery has been able to achieve tumor control in more than 90 percent of cases at 10 year follow-up.
Acoustic neuromas — Surgical resection is often associated with a significant risk of facial paralysis. With Gamma Knife technology, facial function is nearly always preserved and tumor control is achieved in 98 percent of patients at 10 year follow-up.
Metastatic brain tumors — Gamma Knife is extremely effective at controlling metastatic lesions. Control rates vary depending on primary tumor pathology but are on average 90 percent at 1 year and 80 percent at 2 year follow-up. These rates are comparable to surgical resection. Radiosurgery, however, has the advantage of being able to treat multiple lesions at one sitting including surgically inaccessible lesions. Radiosurgery can be used multiple times as necessary and, unlike other forms of external radiation, it is compatible with ongoing chemotherapy.
Trigeminal neuralgia — Approximately two-thirds of patients become pain free and an additional 20 percent achieve significant pain relief at 1 year follow-up. Fifty percent of patients continue to have pain relief at five years.
Longstanding experience — The Yale-New Haven Hospital Gamma Knife Center’s operating experience is the longest of any radiosurgery facility in the state of Connecticut.
Professional expertise — The center’s medical staff has several decades of cumulative experience in the use of Gamma Knife technology and significant experience allowing for predictable outcomes with a high degree of accuracy.
Medical achievements — The center has developed preliminary experience in treating malignant primary brain tumors such as glioblastoma and ependymomas.
Almost half a century ago, the Swedish neurosurgeon and scientist, Lars Leksell, conceived an idea whose application would take many years to realize: that instead of using a surgical probe to selectively destroy discrete targets within the brain, precisely aimed narrow beams of radiant energy could achieve the same result without so much as a skin incision.
Lars Leksell’s relentless devotion to perfecting an ideal instrument for radiosurgery (or “closed intracranial surgery” as he named it) led him to investigate many different radiation-emitting devices.
Among those instruments he used or considered for radiosurgery were the 185 MeV synchrocyclotron and the linear accelerator in the construction of the first Gamma Knife in 1967. In 1987, the first North American 201 Cobalt-60 source Gamma Knife was installed in the United States and today over 237 units are in operation worldwide. The recognition that the Gamma Knife is the gold standard for cranial stereotactic radiosurgery explains why so many major centers have selected it over other competing radiosurgical systems.
Yale-New Haven Hospital Gamma Knife Center is proud to join major teaching institutions on the list of facilities that have chosen to acquire the Gamma Knife and is the only radiosurgery facility in Connecticut to possess such an instrument.
Patients are accepted for treatment at the Yale-New Haven Hospital Gamma Knife Center only after their medical records and previous imaging studies are carefully evaluated by a physician or team of physicians specializing in their particular disorder. Depending on the severity of the case, a referral for treatment can take place within days.
For a referral to the appropriate specialist for your patient or for more information:
(203) 688-4040
Yale-New Haven Hospital Gamma Knife Center
40 Temple Street
New Haven, CT 06510
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