Gamma Knife Frequently Asked Questions



What is a Gamma Knife Perfexion?

The Gamma Knife Perfexion is not actually a knife at all. It is a stereotactic radiosurgical device that uses radiation to non-invasively treats malignant and benign brain tumors, vascular malformations and trigeminal neuralgia in a single (one day) patient visit. Patients are usually treated on an outpatient basis or may require an overnight hospital stay.

How does the Gamma Knife Perfexion work?

Utilizing the latest advanced diagnostic imaging and three-dimensional treatment planning software, the Gamma Knife Perfexion delivers 192 precisely focused beams of gamma radiation to small targets inside the brain through an intact skull. 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.

What are the benefits of treatment with the Gamma Knife Perfexion?

Gamma Knife Perfexion treatment has many benefits. Designed solely to treat intracranial indications, Gamma Knife treatment is bloodless, virtually painless, requires no loss of hair or head shaving 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, and has been in use for over 40 years. This single day procedure is usually covered by most major health insurance companies and Medicare. Gamma Knife treatment may replace conventional brain surgery in some patients with brain tumors, vascular malformations and facial pain where deemed appropriate by our physician team. An individual who would be at risk for complications from conventional surgery or patients with inoperable disease 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 cases, other forms of radiation therapy and chemotherapy. There are also several benefits of having Gamma Knife radiosurgery verses other forms of radiation therapy. Treatment benefits with the Gamma Knife Perfexion (over conventional radiation therapy of the brain) include precise targeting where targeted tissue is treated and spares unnecessary treatment of adjacent, normal brain tissue, only a one-day treatment is required rather than many treatments over several weeks, and it often can be repeated, if necessary. Gamma Knife treatment will not interrupt ongoing chemotherapy for primary disease, unlike some forms of conventional radiation therapy. Gamma Knife can also be used in combination with other forms of radiation therapy if necessary.

What if I am older or have other medical conditions?

Gamma Knife Perfexion radiosurgery is especially valuable for patients whose neurological disorders require a difficult surgical approach or may be impossible to treat using conventional neurosurgical techniques. Patients of advanced age or in poor medical condition can be at an unacceptably high risk for anesthesia and conventional surgery, making Gamma Knife treatment an ideal solution. Gamma Knife Perfexion technology also is highly beneficial for patients whose lesions are situated in a surgically inaccessible or functionally critical area within the brain. In addition, the treatment can be used as an adjunct to the care of a patient who has undergone conventional brain surgery, interventional neuroradiology or conventional radiation therapy or chemotherapy.

What conditions can be treated by the Gamma Knife Perfexion?

Common conditions for which the Gamma Knife is considered are:

Malignant tumors such as:

• Metastases (cancer that has spread to the brain)

• Malignant gliomas

Benign tumors such as:

• Meningiomas

• Acoustic neuromas (vestibular schwannomas)

• Pituitary tumors

Low grade glioma and skull based tumors

Vascular malformations such as:

• Arteriovenous malformations (AVMs)

Cavernous angiomas (cavernous malformations)

Functional disorders such as:

• Trigeminal neuralgia

How are patients referred for Gamma Knife Perfexion treatment?

Most patients are referred to the Gamma Knife program by their doctors. However, some make self-referrals, and our center will accept self referral cases for review by our team. The Gamma Knife team reviews each patient's medical records to determine if Gamma Knife treatment would be appropriate for treatment.

What information is used to determine if Gamma Knife Perfexion treatment is appropriate?

• Medical and Surgical History

• Clinical Examinations

• Imaging studies, such as MRI, CT and/or PET scans

Is Gamma Knife Perfexion treatment effective?

The Gamma Knife’s success rate is impressive. Supported by more than four decades of clinical research, this neurosurgical tool has met with unprecedented results. Clinical applications continue to grow, and its many benefits as a non-invasive treatment modality continue to make it the treatment of choice for certain clinical conditions.

What happens during Gamma Knife Perfexion treatment?

Once a patient’s condition is reviewed by our multidisciplinary team and Gamma Knife treatment is deemed an appropriate, the patient will be scheduled for a treatment day. On the day of treatment, there are several steps that take place. First, a lightweight frame is attached to the patient’s head. Local anesthesia is used before the frame is secured in place. The patient then has an MRI imaging study or, in the case of an arteriovenous malformation, angiography, may be needed in order to precisely locate the diseased area. Data from the imaging study is transferred into the treatment planning computer. While the patient rests, the treatment team (a neurosurgeon, radiation oncologist and physicist) uses advanced software to determine the treatment plan. This takes one or 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. Actual treatment time varies based on the condition being treated and its location. Following treatment, the patient is automatically moved out of the machine, and the head frame is removed. Gamma Knife treatment is usually an outpatient procedure, but some cases may require an overnight stay. If a patient is treated on an outpatient basis, he or she will be observed for a period of time and released. If the procedure has been designated as inpatient, then the patient will be admitted to the hospital.

What will I feel during Gamma Knife Perfexion Treatment?

During the actual procedure, the patient does not see or feel the radiation during treatment. Before the treatment takes place, patients typically feel slight discomfort from the local anesthetic used prior to head frame placement, and have reported feeling pressure for a short time while the pins are inserted to fixate the head frame, but no pain.

Will I be awake during the procedure?

Yes, patients remain conscious throughout the entire procedure and may communicate with the treatment team through a two-way microphone. The treatment team monitors the patient during treatment by video and the microphone.

Will my head be shaved?

No, the head is not shaved. In rare cases, the treatment may cause some hair loss.

What can I expect after the treatment?

When the treatment is finished, the head frame will be removed. Sometimes there is a little bleeding from where the pins were attached to the head. In this case, gauze and pressure will be applied to stop the bleeding and keep the area clean. A temporary head dressing is placed to keep the pin sites clean. It is recommended that the patient take it easy over the next 12 to 24 hours. Pre-Gamma Knife activities can be resumed within a few days.

Is Gamma Knife Perfexion treatment safe?

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

How quickly will the treatment work?

The effects of Gamma Knife Perfexion radiosurgery occur over several weeks to several years, depending on the type of medical condition treated. 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. (For vascular malformations, control is generally considered total obliteration.) The radiation alters the DNA of the tumor or lesion being treated so that the cells no longer reproduce, eventually rendering the lesion static. Some abnormalities dissolve gradually, eventually disappearing. Others simply exhibit no further growth.

What are the complications of Gamma Knife Perfexion treatment?

Early complications may include:

Common side effects:

• Local pain and swelling in the scalp

• Headache

Rare complications:

• Skin reddening and irritation

• Nausea

• Seizure

Delayed complications may include:

Uncommon complications:

• Local loss of hair in superficial lesions

• Local brain swelling in the treatment site

• Local tissue necrosis in the treatment site

Rare complications:

• Visual loss (dependent on diagnosis and areas treated)

• Hearing loss (dependent on diagnosis and areas treated)

When can I return to my normal, pretreatment activities?

Most patients can typically return to pre-treatment activities within a few days. The only restrictions patients will have are the same ones they had prior to treatment.

Is Gamma Knife treatment more or less expensive than traditional brain surgery?

Cost studies have shown Gamma Knife radiosurgery to be less expensive than conventional neurosurgery because it eliminates lengthy post-surgical hospital stays, expensive medication and potentially months of rehabilitation. Importantly, there are virtually no post-surgical disability and convalescent costs with a Gamma Knife procedure.

Will my insurance cover Gamma Knife Treatment?

Gamma Knife radiosurgery is reimbursed or covered by most insurance companies, PPOs, HMOs and Medicare. Our center staff will help potentials patients navigate the insurance process in relation to Gamma Knife treatment.


What happens during a Gamma Knife Procedure?

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