CyberKnife radiosurgery for brain and spinal tumors

Abstract

Object: Radiosurgery utilizes stereotactic principles of localization and multiple cross-fired beams to deliver a large radiation dose to a well-defined target with little or no fractionation. The CyberKnife® is an image-guided radiosurgical instrument that by design avoids the use of a stereotactic frame. The prototype for this technology was first installed at Stanford University Hospital in 1994 and has been used to treat patients with brain or spinal lesions, many of whom lacked good surgical or radiotherapeutic treatment options. Methods: Recent phantom testing with the CyberKnife system has demonstrated that under nearly all circumstances, targeting accuracy is accurate to better than 1.2 mm (RMS error). Over the past 7 years, CyberKnife radiosurgery was used to treat 369 patients who harbored a large variety of brain or spine tumors. Three hundred and thirty-eight (338) of these patients had brain tumors, while 31 had lesions of the spine. Depending on the nature of the lesion to be treated, the CyberKnife was used to administer either single-fraction or limited-fraction (hypofractionated) radiosurgery. The average number of fractions used per patient was 1.9. Clinical situations in which the CyberKnife's flexibility proved to be uniquely beneficial will be presented. Conclusions: This initial experience at Stanford demonstrates the benefits of using image-guided robotic radiosurgery for a broad range of brain and spine tumors, many of which were untreatable with any other technology. The CyberKnife is becoming an increasingly accepted method for performing radiosurgery and promises to extend this procedure to almost any location in the body.