What is the Gamma Knife?

The Leksell Gamma Knife® was developed by Lars Leksell, M.D., a neurosurgeon, and Borje Larsson, M.D., a physicist in the 1950's. Gamma Knife is a radiosurgery technique that allows a neurosurgeon to target and deliver a single dose of radiation to a very specific areas in the brain without actually making an incision. Gamma Knife radiosurgery is recognized world wide as the preferred treatment for metastatic brain tumors. It is proven safe and a very effective non-operative treatment for many intracranial disorders.

How does it work?

No incision is made. Instead of surgically treating abnormal areas of the brain, the Gamma Knife's uses 190 radiation sources focused on the area to be treated. The gamma radiation painlessly, silently and with extreme precision treats the abnormal tissue. Only the treated area receives a significant dose of radiation, which is unique compared to other radiation therapy treatments that do not spare the surrounding brain tissue. Generally only one treatment is necessary. Gamma Knife radiosurgery can be repeated in other areas of the brain at the same or different times.


Gamma Knife radiosurgery is recognized as an effective treatment for multiple conditions such as: Acoustic Neuromas Arteriovenous malformations Astrocytomas Meningiomas Pineal tumors Pituitary tumors Glioblastoma Multiforme Metastatic tumors to the brain Trigeminal Neuralgia Essential Tremor Parkinsons tremor.

You go home the same day after Gamma Knife Radiosurgery Risks:

The risks of Gamma Knife Radiosurgery vary from patient to patient based on location of the area to be treated and the condition being treated. Treatment risks include but are not limited to radiation necrosis, secondary malignancy caused by the radiation (ie: formation of new tumor), hemorrhage, infection from the placement of the stereotactic head frame, paralysis and death. Gamma Knife treatment doesn't eliminate the potential need for open surgery. In some cases swelling in the region treated may require steroid therapy or surgery. Discuss your particular situation with your treating physician.

Treatment Options

There are four phases to the treatment process:

  1. Application of the head frame
  2. Imaging
  3. Treatment planning
  4. The treatment itself

Frame Application:

The application of the Leksell Stereotactic Coordinate Frame® is the only uncomfortable portion of the procedure. Local anesthetic is injected into the scalp. The frame clamps on to the patients head so it will not move during treatment. Most patients describe the sensation of frame application as "pressure". Once the frame is in place the "pressure" sensation lessons and you will notice the added weight of the frame. After the frame is in place several measurements are made. These measurements are entered into the Gamma Knife computer. These measurements are used in calculations that will help us position you for treatment.


After the frame is placed and the measurements are completed an imaging study is performed. This is usually a high resolution MRI scan of the brain, in some cases it is a CT scan. When AVM's are being treated an angiogram may be obtained. The imaging study is loaded into the Gamma Knife computer.

Treatment Planning:

The MRI images are used by the Gamma Knife team to develop a treatment plan specific for each patient. The exact location of the area in the brain to be treated is identified by your neurosurgeon and radiation oncologist.


Once the treatment plan is developed the patient is positioned for treatment on the Gamma Knife couch. Once positioned, the couch will move automatically into the Gamma Knife Unit. The system automatically focuses the Cobalt-60 beams on the target. The treatment is silent and painless. You will be monitored by the staff continuously during the treatment.

On the day of treatment:

  1. You will need to check in at admissions at the time instructed in the main lobby. Please allow time to get to Roswell Park Cancer Institute and park.
  2. You will be taken to the Gamma Knife Center where you will meet your nurse.
  3. After your nursing evaluation, the head frame will be applied by Dr. Landi.
  4. You will then have an imaging study of the brain (usually an MRI scan) with the head frame in place.
  5. Your imaging study will be used by Dr. Landi and Dr. Shah to develop your treatment plan.
  6. Your Gamma Knife treatment is painless and silent. It may take 15 minutes to over an hour depending on what is being treated. If you have a favorite CD that you would like to listen to during the treatment, bring it with you.
  7. After the treatment is completed, the head frame will be removed. You will be discharged shortly thereafter. Your family should wait in the radiation oncology waiting area on the ground floor. They will be able to see you immediately after the procedure. If you have any questions call our office 716-631-3555