Why Gamma Knife® surgery is the best choice for treating brain tumors

Leksell Gamma Knife is the ONLY stereotactic radiosurgery system specifically approved for treating brain tumors, also known as brain metastases, based on long-term scientific proof. Here’s why leading neurosurgeons worldwide choose Gamma Knife surgery for their patients:

Accuracy is the single most important aspect of SRS

Gamma Knife radiosurgery sets the bar for accuracy, with guaranteed precision that enhances physician confidence and ensures patient safety. (1)

This superior level of accuracy is due to three factors:

  1. Gamma Knife was designed specifically to provide the very best radiosurgical treatment of brain tumors
  2. The radiation source never moves during operation
  3. The patient’s head is stationary

When treating a target as delicate as the brain, neurosurgeons try to avoid any movement that might reduce accuracy. CyberKnife, a linear accelerator used to treat the whole body, has a continually moving arm.

Frameless neurosurgery is a myth

Neurosurgeons will tell you that immobilizing the target – the patient’s head – is the first step in performing any type of brain surgery. The most widely used neurosurgical head frame – called a stereotactic frame – is manufactured by Elekta, and it’s the same stereotactic frame used with Gamma Knife surgery.

CyberKnife claims that no head frame is required for stereotactic radiosurgery. Instead they use a claustrophobic mask that is pressed against the patient’s face for hours. And despite the constraint, their head can still move. (2)

Reducing excess radiation to the body

The Gamma Knife is designed so all radiation focuses into a single point within the brain and the shielding of the machine specifically protects the body from excess radiation.

Excess radiation is not well-contained in the CyberKnife design, and its treatment delivers as much as 100 times more stray radiation compared to Gamma Knife radiosurgery. (3)

Eliminating X-rays of the brain

With Gamma Knife radiosurgery, a head frame is attached with temporary placement pins and the patient has a single MRI – the preferred method of imaging the brain. There are no X-rays.

Because CyberKnife and other linac treatments recommend use of a face mask instead of a head frame, X-rays of the brain must be taken every two minutes during treatment to ensure the target hasn’t moved. (2) These added X-rays increase radiation exposure to the patient and lengthens treatment time.

Treating the body is different from treating the brain

Leksell Gamma Knife is specifically optimized for the brain. Because the head can be immobilized during Gamma Knife radiosurgery, physicians feel confident in the accuracy of their treatment and can use a single, high dose of radiation. Patients can return home the same day and resume normal activities.

The body and its internal organs are virtually impossible to immobilize, requiring imaging throughout a linac treatment. The physician needs constant imaging to treat with confidence and often reduces the dose and increases the number of treatment sessions to compensate.

Unmatched clinical evidence and experience

Gamma Knife radiosurgery has been used to treat over half a million people, with treatments documented in more than 2,000 peer-reviewed clinical papers…including one that tracks patients over a 15-year period.

Leksell Gamma Knife is such an established standard of care that Medicare has designated a unique authorization code for radiosurgery on the Gamma Knife.

CyberKnife has been in use for more than 15 years and has little or no clinical evidence for treating brain tumors. (4) According to the system’s manufacturer, “the safety and effectiveness of the CyberKnife system for certain uses is not yet supported by long-term clinical data. (5)

This lack of long-term clinical data is why insurance companies are likely to decline or deny coverage for CyberKnife treatments.

For more information on the treatment and care of brain tumors go to braintumortreatment.org

Learn more about Gamma Knife SRS:


  1. Mack, Kreiner et. al; “Quality assurance in stereotactic space. A system for verifying the accuracy of aim in radiosurgery.” Medical Physics 29:4. April 2002.
  2. Petti et al, Med Physics, 33:1770-9, 2006
  3. Murphy et al, Patterns of patient movement during frameless image guided radiosurgery, IJROBP, Vol 55, No. 5, pp 1400-1408, 2003
  4. Medline search, “Brain Tumor, radiosurgery”, January 2007
  5. US SEC Form S-1, Accuray Inc., 2007