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What is Gamma Knife?

The Gamma Knife® is not actually a knife at all. It is a stereotactic radiosurgical devise that non-invasively treats malignant and benign brain tumors, vascular malformations and trigeminal neuralgia in a single-session on an out-patient basis. Since this invisible radiation is the "scalpel", there is not actual cutting into the body and as a result many of the risks of traditional surgery are avoided. With 40 years of clinical use and over 3,000 published per review studies, the Gamma Knife has proven to be the most accurate and effective radiosurgery treatment system. Worldwide over 800,000 people have been treated with this technology. Treatment indications continue to expand and the many benefits as a non-invasive treatment tool continue to make the Gamma Knife the preferred treatment choice for many clinical conditions.

What are the advantages of Gamma Knife?

Gamma Knife Perfexion treatment has many benefits. It is bloodless, virtually painless, does not result in hair loss and has a rapid return to pre-treatment activities. Gamma Knife treatment also has excellent, well-documented clinical outcomes for a variety of brain diseases and disorders.

There are also several benefits of having Gamma Knife radiosurgery versus other forms of radiation surgery.

The benefits of Gamma Knife Perfexion treatment differs from conventional radiation therapy of the brain because it is only directed to targeted areas and spares unnecessary treatment of adjacent, normal brain tissue. Only a one-day treatment is required rather than many treatments over several weeks and the treatment often can be repeated if necessary.

Gamma Knife treatment can also replace brain surgery in some patients with brain tumors, vascular malformations and facial pain. An individual who would be at risk for complications from conventional surgery may be a candidate for Gamma Knife radiosurgery. Gamma Knife treatment can be used when prior surgery or radiation therapy has failed to control the disease process. It can also be used in conjunction with conventional surgery in previously inoperable conditions.

How does the Gamma Knife Perfexion work?

Utilizing advanced diagnostic imaging and three-dimensional treatment planning software, Gamma Knife delivers 192 precisely focused beams of gamma radiation to small targets inside the brain. Radiation is only delivered at a single, finely focused point where all 192 beams converge to treat the diseased tissue, while nearby healthy tissue is spared. The radiation causes the DNA in the targeted cells to die and shrink over time. For arteriovenous malformations (AVMs) the radiation causes the treated blood vessels to thicken and scar to stop the abnormal blood flow. For trigeminal neuralgia, the nerve firing the painful impulse is treated stopping its ability to conduct the painful impulse.

What condition can be treated with the Gamma Knife?

Gamma Knife can be considered for many malignant (cancerous) and benign (non-cancerous) conditions.

  • Malignant tumors such as metastases (cancer that is spread to the brain) and malignant gliomas
  • Benign tumors such as meningiomas, acoustic neuromas, pituitary tumors and low grade glioma and skull-based tumors
  • Vascular malformations such as arteriovenous malformations (AVMs) and cavernous angiomas
  • Funcational disorders such as trigeminal neuralgia. Some facilities are also treating essential tremor.

Contact our Gamma Knife Coordinator for more details.


Are Gamma Knife procedures safe?

The Gamma Knife allow non-invasive brain surgery to be performed with extreme precision while sparing healthy tissues surrounding the targeted treatment area. Also, because neither a surgical incision nor general anesthesia is required, the risks usually involved with open brain surgery, such as hemorrhage or infection, may be reduced. Hospitalization is rarely required and recovery time is minimal. While individual patient outcomes may vary, patients normally resume their normal pre-surgery lifestyle within 24 hours.

How quickly do you see results?

The effects of Gamma Knife radiosurgery occur over several days to several years, depending on the type of medical condition treated. The radiation alters the DNA of the tumor or lesion being treated so that the cells no longer reproduce, eventually rendering the lesion inert. Some abnormalities dissolve gradually, eventually disappearing. Others simply exhibit no further growth. The effectiveness of the treatment is monitored by MRI scans at regular intervals. The goal of radiosurgery is tumor control, which is defined as stable tumor size or tumor shrinkage.

Is the Gamma Knife painful?

Patients may feel a slight pressure when the Gamma Knife frame is attached to the head. Medication is given to help patient relax and topical and local anesthetic will be used to numb the pin sites. The Gamma Knife procedure itself is completely painless.

Why is it called a Gamma Knife?

The term refers to the "gamma" radiation emitted by the machine and the scalpel-like accuracy with which it treats affected areas of the brain.

What should I expect for a typical Gamma Knife treatment?

Once a patient's condition is reviewed by our multidisciplinary team and Gamma Knife treatment is deemed appropriate, the patient will be scheduled for treatments. One the day of treatment, there are several steps that take place. First, a lightweight frame is attached to the patient's head. Hair does not have to be cut or shaved. The patient will be given some medication to help them relax and topical and local anesthetic is applied to the areas where the frame is being attached. The patient then has an MRI or CT imaging study to precisely locate the diseased area. Data from the imaging study is transferred to the treatment planning computer. While the patient rests in a private room with his/her family, the treatment team (a neurosurgeon, radiation oncologist and physicist) uses advanced software to determine the treatment plan. This takes one to two hours to complete, depending on the complexity and location of the disease. When the individual treatment plan is completed, the patient is placed on the Gamma Knife couch and precisely positioned. The patient is then moved automatically, head first into the machine, and treatment begins. Treatment typically lasts from 15 minutes to an hour or more, during which time the patient feels nothing unusual. After the treatment is completed, the patient is automatically moved out of the machine, and the head frame is removed. Patients are monitored for about 60 minutes and then sent home with discharge instructions.

What can I expect after treatment?

When the treatment is finished, the head frame will be removed. Sometimes there is a little bleeding form where the pins were attached to the head. Antibiotic ointment is applied to the pin sites and a gauze dressing is wrapped around the patient's head. The patient is instructed to keep the dressing on for 2-3 hours and to take it easy for 12 to 24 hours and then resume their normal pre-treatment activities.

Is Gamma Knife surgery covered by insurance?

Because of the high success rate and low cost of Gamma Knife surgery (compared to open brain surgery), most insurance companies, as well as Medicare, cover the procedure. Our Gamma Knife Nurse Coordinator is happy to discuss our costs with you or your insurance company.

What other expenses should I plan for?

Because many of our patients travel from out of town, they may need to consider additional costs for travel, overnight lodging and meals. MidMichigan Medical Center - Midland offers special pricing on lodging as part of our Hospitality Service.

Would Gamma Knife surgery be an option for me?

We would be happy to review your case. Contact our Gamma Knife Nurse Coordinator for more information or to arrange for a no-obligation review of your records.

Gamma Knife® is a registered trademark of Elekta Group.

The MidMichigan Difference

  • MidMichigan Medical Center-Midland is a leader in neuroscience and cancer care in the state of Michigan.
  • MidMichigan's Gamma Knife Perfexion is the only machine of its kind in Michigan. 
  • Our board-certified neurosurgeons and radiation oncologists are specially trained and experienced in Gamma Knife radiosurgery.
  • Our Gamma Knife Coordinator will serve as your personal guide, walking you and your family through each step of the treatment process.
  • MidMichigan is located in Midland, Michigan, a safe and friendly suburban community with easy highway and airport access. It is conveniently located for patients in Michigan and the MidWest.
  • MidMichigan provides hospitality services for Gamma Knife patients including lodging and other amenities. Maps and driving directions are also available.
  • We work with your physician throughout the evaluation and treatment process, and will continue to be available for consultation with your physician during your follow-up care.

Is Gamma Knife Right for You?

Call Toll Free
(866) 644-2662

Dennis Ouillete, R.N. photoGamma Knife treats brain conditions with pinpoint accuracy that surgical interventions can’t match. Call our Gamma Knife coordinator, Dennis Ouillette, R.N., to arrange a no-obligation personalized review of your case. Dennis can also answer your questions about costs and insurance, treatment, transportation and lodging.

Contact Dennis