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Gamma Knife® versus the Accuray CyberKnife®

Gamma Knife stereotactic radiosurgery (SRS) is the gold standard for treating intracranial SRS procedures. It has been used for nearly four decades, with more than 350,000 cases treated worldwide. It has provided the data for more than 2,000 medical publications. Gamma Knife is used as the standard against which other technologies, such as the Accuray CyberKnife, are measured.

UK HealthCare's team of specialists offer the following comparison of Gamma Knife and CyberKnife:

Gamma Knife




201-source cobalt unit designed exclusively for non-invasive brain surgery


Single-source linear accelerator with robotic arm to compensate for patient movement during treatment;  not exclusively used for intracranial SRS 

Radiologic accuracy better than 0.3 mm


1 mm accuracy; dose outside the target area is two to six times greater than with Gamma Knife

Rigid immobilization to prevent head movement using a lightweight stereotactic head frame fixed to the outer skull. Provides exact MR and CT correlation from planning to treatment delivery in 3D.  


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 CT correlation from planning to treatment delivery in 3D. The CyberKnife is inherently less accurate since the positioning is optically guided, not head-frame based.  

Treatment delivered during one session


Single or multiple treatments, possibly over a period of days

Target position is confirmed 10 times per second 


Target position confirmed once every 10 seconds

Page last updated: 2/16/2015 2:27:30 PM