Traditional stereotactic radiosurgery therapies rely on a rigid metal frame fixed to a patient's skull for head immobilization and target localization. These frame-based systems have numerous limitations, including:

Restricting treatment to the brain.
Limiting the possible angles which radiation could be delivered.
Causing considerable discomfort to the patient.
Requiring inpatient hospitalization.

In contrast to the traditional frame-based radiosurgical treatments, the CyberKnife® uses noninvasive image-guided localization, and a robotic delivery system. This combination of technologies enables the CyberKnife® to overcome the limitations of older frame-based radiosurgery.