Competition to treat benign and malignant brain lesions, vascular malformations, and functional conditions with stereotactic radiosurgery (SRS) has increased dramatically in recent years. All-in-one systems like the Accuray CyberKnife® are aggressively positioning themselves as being comparable to the Leksell Gamma Knife® in effectiveness and efficiency.

Gamma Knife stereotactic radiosurgery is the gold standard for the treatment of intracranial SRS procedures. Its clinical efficacy has been documented across nearly four decades, with more than 350,000 cases treated worldwide providing the data for 2,000+ publications in peer-reviewed medical literature. It is used as the performance metric against which other technologies (such as the Accuray CyberKnife®) are measured. Gamma Knife® has the most accurate dose planning, the most conformal treatment and lowest dose of radiation to normal tissue.

What is critical is the difference in dose outside the target for Gamma Knife® compared to the Accuray CyberKnife®.
 
Perhaps the easiest way is to compare, point for point, the Gamma Knife® with the Accuray CyberKnife®.

Leksell Gamma Knife®	Accuray CyberKnife®
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
Radiological accuracy better than 0.3mm	1 mm accuracy; dose outside the target area is 2-6x greater than with the 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 Accuray 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

From a technical standpoint, the Gamma Knife® is unparalleled in its concept and design for maximal accuracy and intracranial targets.

From a clinical standpoint, it has the longest track record for numbers and results.

At San Diego Gamma Knife Center we have physicians who actually have experience in performing radiosurgery, and are not in the process of learning.