Gamma Knife

• designed exclusively for non-invasive brain surgery with a 201 source cobalt unit
• radiological accuracy better than 0.3 mm
• Rigid immobilization, to prevent head movement using, using a lightweight stereotactic head frame fixed to the skull. Provides exact MR and CT correlation from planning to treatment delivery in 3D.
• treatment delivered during one session
• target is confirmed 10 times per second

CyberKnife

• uses a single source linear accelerator; not exclusive to brain surgery
• 1 mm accuracy; dose outside the target area is 2-6 times greater than with the Gamma Knife
• Non-rigid immobilization reduces head movement by using a thermoplastic face mask that is shrink wrapped to the table during treatment. Provides relative MR and CR correlation from planning to treatment delivery in 3D. The CyberKnife is inherently less accurate because head positioning is optically guided, not head frame based.
• single or multiple treatments, possibly over a period of days
• target is confirmed once every 10 seconds