Frequently Asked Questions
Frequently Asked Questions about Gamma Knife Surgery
- Why is it called a Gamma Knife?
The original Stereotactic Gamma Unit made a "knife-like" lesion in the brain leading to it being called the "Gamma Knife".
- How long has Gamma Knife Radiosurgery been available?
The first unit became operational in Sweden in 1968. The first unit in the United States was installed at the University of Pittsburgh in 1987.
- Can Gamma Knife Radiosurgery be used for other body areas?
No. Gamma Knife Radiosurgery was invented by a Neurosurgeon for non-invasive brain surgery. The physical design of the unit prevents using it for lesions in other areas of the body. It can only treat lesions in the brain and head.
- What are the side effects of Gamma Knife Radiosurgery?
Side effects are limited and uncommon. Since there is no incision, there is no risk of infection, blood loss or spinal fluid leak. Brain or other tissue adjacent to the lesion treated can be injured but the risk of that is usually small. The neurosurgeon will discuss specific risks associated with lesions to be treated with patients in the initial consultation, prior to treatment.
- Is Gamma Knife Radiosurgery painful?
The actual procedure is painless. Head frame attachment is done with local anesthetic and mild sedative and is usually not uncomfortable.
- Will the rest of my head be radiated?
The 192 Cobalt sources in a Gamma Knife Perfexion unit all converge to produce a single beam of radiation which target the lesion being treated. Consequently, any point in the brain, away from the lesions being treated, is exposed to a minimal dose of radiation.
- What are the advantages of Gamma Knife Radiosurgery versus tradional brain surgery?
When it is possible to do Gamma Knife Radiosurgery as an alternative to traditional "open skull" neurosurgery, the risks are generally lower, it is less painful, there is no hospitalization and the costs are usually lower.
- Is it cost effective?
Costs associated with Gamma Knife treatment are usually considerably less than for traditional neurosurgical treatment of the same lesion. The most obvious cost saving, to the patient, is from the lack of recovery after Gamma Knife Radiosurgery. The procedure is typically done in a single, outpatient visit, so the cost of hospital stays is reduced. Since there is little convalescence needed after Gamma Knife Radiosurgery, there is no prolonged absence from work or other activities as there often is after more traditional "open skull" brain surgery.
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
- 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 and a light sedative is used before the frame is secured in place. This frame will remain in place throughout the treatment process, and ensures no movement occurs during the process. This frame allows Gamma Knife treatment to be extremely accurate. Next, the patient has an MRI or CT 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. The radiation treatment cannot be seen or felt. Actual treatment time varies based on the condition being treated and its location. When treatment is completed, 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.
- 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 sound. Patients can listen to music, and some even fall asleep during treatment.
- Will my head be shaved?
No, Gamma Knife treatment does not require a patient's head is be shaved. In rare cases the treatment may cause some temporary 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 greatly reduced. Hospitalization is rarely required and recovery time is minimal. While individual patient outcomes may vary, patients may resume their normal pre-treatment lifestyle within a few days. Gamma Knife treatment has been in use for over 40 years. Over 600,000 people worldwide have been treated with Gamma Knife, and more than 3,000 peer-reviewed clinical papers have been written about Gamma Knife treatment. Gamma Knife is also FDA approved.
- 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 like open brain surgery. Patients of advanced age or in poor medical condition can be at an unacceptably high risk for general 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 an 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, conventional radiation therapy, or chemotherapy.
- 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 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. 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.
- 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 you will have are the same you had prior to your treatment.
- How does treatment with the Gamma Knife Perfexion differ from other forms of radiation therapy?
Treatment with the Gamma Knife Perfexion differs from other forms radiation therapy in a couple of ways. The Gamma Knife is a form of stereotactic radiosurgery which only directs treatment to targeted areas and spares adjacent, normal brain tissue. Other forms of radiation therapy do not provide such a 'fitted' treatment, and may not deliver as high of a treatment dose as Gamma Knife. Treatment with the Gamma Knife is performed in a single (one) day treatment session versus other forms of radiation therapy which may require three to thirty or more treatments over several weeks. Gamma Knife treatment can often be repeated if necessary where other forms may not. Gamma Knife treatment also does not typically interrupt or impede ongoing chemotherapy for a primary cancer, and may not require patients to hold other medications for treatment.
- Will my insurance cover this procedure?
Gamma Knife radiosurgery is reimbursed by most insurance companies, PPOs, HMOs, and Medicare.