CyberKnife vs Gamma Knife

Both systems provide stereotactic radiosurgery/radiotherapy, but their radiation sources, delivery mechanisms and clinical flexibility differ.

Feature	CyberKnife	Gamma Knife
Radiation source	Compact linear accelerator producing X-rays	Multiple sealed radioactive Cobalt-60 sources producing gamma rays
Delivery	Robotic arm moves the radiation source around the patient	Many fixed gamma beams converge on a target
Beam direction	Many dynamically selected angles	Fixed source geometry
Image guidance	Integrated image guidance and tracking	Uses stereotactic localization; modern systems may incorporate image guidance
Patient motion	Can track/correct for certain motion depending on system and site	Traditionally requires rigid/stereotactic immobilization; modern workflows vary
Typical use	Intracranial and selected extracranial lesions	Primarily intracranial lesions
Flexibility	Highly flexible beam positioning	Highly precise fixed geometry
Radiation source replacement	No radioactive cobalt source replacement; linac maintenance required	Requires management/replacement of radioactive sources according to system and regulations

CyberKnife

CyberKnife uses a small linear accelerator mounted on a robotic arm. The robot directs X-ray beams from many angles while image guidance helps localize the target.

Gamma Knife

Gamma Knife uses multiple Cobalt-60 sources arranged around the patient. Their gamma beams are focused on a target so that the target receives a high dose while surrounding tissue receives substantially less dose.

Conclusion

CyberKnife = robotic linac-based, flexible image-guided delivery.

Gamma Knife = multi-source Cobalt-60 stereotactic gamma-ray treatment, mainly for intracranial targets.