What to Expect
Preparing for Your Treatment Day
Once you and your doctor confirm that you are a candidate for Gamma Knife radiosurgery, you will be scheduled for a treatment day. Our Gamma Knife Center staff will work with you to get the procedure scheduled as well as any necessary paperwork.
Once scheduled, here are some preparations you will need to make the night before your Gamma Knife procedure:
- Make sure you discuss all medications you are taking with your Gamma Knife physician prior to treatment day.
- Make sure to wash your hair, but avoid using any heavy products in your hair such as styling cream, spray or wax.
- Avoid eating or drinking anything but water after midnight as this helps reduce risk of stomach upset during the procedure.
On Treatment Day
On the day of your Gamma Knife treatment, you will need to arrive at your scheduled time to the Gamma Knife Center, which is located inside the Northern Westchester Cancer Treatment Center building. Please remember to:
- Wear loose, comfortable clothing
- Avoid wearing any make up or cosmetics as well as any hair products or accessories
- Avoid wearing any jewelry
Once you check in with our staff and any additional paperwork and/or questions you may have are answered, you will be taken back to begin the Gamma Knife surgery treatment process. Depending on your comfort level, you may receive oral and/or intravenous (IV) sedatives to help you relax during the procedure.
When you arrive for your Gamma Knife treatment, you will be greeted by our staff and provided with a consent form for your review and signature.
Your Gamma Knife treatment will consist of the following steps:
- Placement of the Head Frame: A stereotactic frame will be placed on your head and remain there throughout treatment. The frame is needed as a reference point during treatment planning, and it is used to hold your head in the exact position required for precise treatment.
- Obtaining Precise Images: MRI, CT scans, or Angiography (a way to visualize the blood vessels) will be used to obtain images that clearly define where the tumor, AVM, or treatment site is located. After the required images are obtained, you can relax while the team reviews the images and plans your treatment.
- Treatment Planning: Once the images are transferred to the Gamma Knife's computer planning system, the team examines them and accurately defines the target. The detailed treatment plan they create determines how long treatment will take. Planning a typical Gamma Knife treatment usually takes approximately one hour.
- Treatment: Once the treatment plan has been carefully reviewed by the team for precision and safety and has been thoroughly explained to you, your treatment will begin. You will enter the Gamma Knife room and recline on the couch portion of the unit. The team will attach the frame to the machine, and the treatment will begin. The team conducts treatment in an adjacent room, maintaining contact with you through video and intercom. You may choose to listen to the radio or music of your choice. When your treatment is over, the head frame is removed, and most individuals return to pre-treatment activities within a day or two.
- Post Gamma Knife Treatment: Your physician will monitor your treatment results by taking periodic MRI, CT scans or Angiography. The staff at Gamma Knife Center will stay in contact with your physician to monitor your progress.
After Your Treatment with Gamma Knife Perfexion
Most patients return to their pretreatment activities in roughly 24-72 hours. The only restrictions you will have will be the same as those prior to treatment.
The effects of Gamma Knife treatment occur over time, several weeks to years depending on the condition treated. The treatment goal with the Gamma Knife Perfexion is control. For tumors, the radiation delivered by the Gamma Knife unit alters the DNA of tumor cells so that they can no longer reproduce, eventually rendering the lesion static. For vascular disease, the goal of treatment is total obliteration of blood flow through the abnormal blood vessels. The abnormal blood vessels treated with the radiation swell and eventually cut off blood flow through them. For trigeminal neuralgia, the goal for treatment is reduction of or freedom from pain and medications.
Potential Gamma Knife Side Effects of Treatment
Even though Gamma Knife radiosurgery is a non-invasive technique, some patients do experience side effects of the radiation after treatment. Your Gamma Knife physicians should discuss potential complications of treatment prior to your treatment day. The common side effects can include headache and local swelling or tenderness of the pin sites. Rare side effects can include skin irritation, severe headache, and nausea.
Potential Treatment Results
With over 40 years of clinical use and results, the Gamma Knife has proven to be effective for a variety of brain diseases and conditions. While individual results may vary, here are some of the results for a few of the indications treated with Gamma Knife:
Metastatic Brain Tumors
Metastatic brain tumors are spread to the brain from elsewhere in the body. Over 252,400 cases of single and multiple brain metastases have been treated by the Gamma Knife worldwide. Clinical research has shown local control provided by Gamma Knife radiosurgery treatment of brain metastases in any brain location generally exceeds 85%.
Over 63,000 acoustic neuromas have been treated worldwide with Gamma Knife, and clinical evidence reports long-term tumor control rates of 93-100% for tumors 3cm or less. Gamma Knife radiosurgery typically carries a high hearing preservation rate of 60-90% for most patients. Research also supports that Gamma Knife treatment of acoustic neuromas helps preserve facial/trigeminal nerve function in more than 95% of patients.
Over 90,000 cases worldwide have been treated with Gamma Knife. Typically reserved for tumors less than 4 cm and those not causing a multitude of symptoms, Gamma Knife provides long-term tumor control in about 93-98% of patients. For tumors less than 3.5 cm, clinical data supports that treatment results with Gamma Knife is equivalent to that of surgical resection of Simpson Grade 1 tumors. Gamma Knife treatment provides superior control rates for Simpson Grade 2 and Grade3-4 resections. Gamma knife treatment can also be used to treat residual tumor, the tumor resection area, or for tumor recurrence or regrowth after surgery.
Over 50,000 cases have been treated with Gamma Knife worldwide. Clinical research supports tumor control rates between 90-100% with Gamma Knife treatment for both secreting and non-secreting tumors to be between 90-100%. For secreting tumors, research reports about 50-60% of patients will achieve hormonal control/balance 12-60 months after treatment.
Arteriovenous Malformations (AVMs)
Over 71,600 AVMs have been treated with Gamma Knife radiosurgery worldwide. Obliteration of blood flow typically occurs in 70-90% of patients over a period of one to six years.
Over 43,400 cases of trigeminal neuralgia have been treated with Gamma Knife worldwide. Clinical evidence supports 78-94% pain relief within three months post treatment. Most patients are able to begin tapering or decreasing medications. Long-term pain relief varies from 32-81% as reported by various treatment centers. Level 2 clinical evidence supports Gamma Knife to have the lowest rate of morbidity or associated sensory nerve dysfunction when compared to other treatments techniques.