The CyberKnife system is a method of delivering radiotherapy, with the intention of targeting treatment more accurately than standard radiotherapy. The two main elements of the CyberKnife are the radiation produced from a small linear particle accelerator and  a robotic arm which allows the energy to be directed at any part of the body from any direction.

Comparison with other stereotactic systems
One of the most widely known stereotactic radiosurgery systems is the Gamma Knife. The Gamma Knife was originally developed by Lars Leksell, remains the gold standard method for delivery of stereotactic radiosurgery to the brain, and is manufactured by Elekta. John Adler, the inventor of the CyberKnife system spent time training with Lars Leksell in Stockholm at the Karolinska Institute in 1985. The GammaKnife system uses 201 Cobalt-60 sources located in a ring around a central treatment point ("isocenter"). The Gamma Knife system is equipped with a series of 4 collimators of 4mm, 8mm, 14mm and 18mm diameter, and is capable of submillimeter accuracies. The Gamma Knife system does however require a head frame to be bolted onto the skull of the patient, and is only capable of treating cranial lesions. As a result of frame placement, treatment with Gamma Knife does not require real time imaging capability as the frame does not allow movement during treatment. Operators of the Gamma Knife system have argued that it is likely to be more accurate than CyberKnife for these reasons. The Cyberknife Society and Accuray maintain that there are no peer-reviewed published papers that establish Gamma Knife as being more accurate than CyberKnife.
Another popular stereotactic system is the Novalis produced by Brainlab. The Novalis radiosurgery system utilizes a small computer-controlled micro Multi Leaf Collimator (mMLC) that can produce many complicated shapes. The maximum radiation field size that the Novalis can produce is 98 mm x 98 mm and the minimum is 3 mm x 3 mm, allowing a considerable range of tumors to be treated. The Novalis system also has X-ray imaging using amorphous silicon flat panel X-ray detectors. A 2D/3D image fusion of the patient setup X-rays with digitally reconstructed radiographs from a planning CT scan quickly determines a correction vector for the patient's position. Infrared fiducial markers attached to the patient then allow precise tracking of the correction vector's application to the patient's position via an infrared camera, and a couch that can move in all six dimensions enables the precise positioning of the patient. Patient immobilization can also be performed framelessly with ExacTrac Patient Positioning, which uses high-resolution stereoscopic X-Ray images to detect and visualize the patient's internal anatomy before or during treatment. Novalis has become a leading player in the world of neurosurgery.

Conventional X-ray therapy linear accelerators can be utilized for radiosurgery, either by the use of additional blocking cones or by a removable or built in micro MLC system. Examples of removable micro MLC units are the Ergo from 3D line, the mMLC manufactured by Brainlab, and the AccuKnife produced by Direx., or the Novalis TX

Clinical uses