Cyberknife Radiosurgery - A New Treatment Method for Image-guided, Robotic, High-precision Radiosurgery
Cyberknife Radiosurgery - A New Treatment Method for Image-guided, Robotic, High-precision Radiosurgery
Cyberknife Radiosurgery – Overview
Cyberknife technology is based on radiosurgical principles that have been in clinical practice for 30 years. Radiosurgery is the precise application of a high (tumour-destructing) dose of radiation in a precisely defined target volume, while protecting the surrounding healthy tissue. During radiosurgery, many radiation beams from different directions intersect in the tumour region, where they accumulate. The surrounding healthy tissue receives only a small amount of the total dose. Until recently, the Gamma Knife system was the standard instrument for neurosurgical applications, and some centres use linear accelerators (linacs) for clinical radiosurgical procedures. These systems, which are used mostly in conventional radiation oncology, have to be readjusted for every radiosurgical treatment. They must also undergo physical testing, because radiosurgical applications demand significantly higher quality and precision requirements than conventional radio-oncological applications. However, Gamma Knife and conventional linacs share the same necessity of applying an invasive stereotactic ring on the patient’s head in order to achieve the desired accuracy of ±1mm. The revolutionary development of the Cyberknife technology, combining integrated image-guided and robotic technology, has led to a paradigm shift in radiosurgery.1,2
Advantages of Cyberknife Radiosurgery
With Cyberknife technology, an invasive stereotactic head frame is no longer required in order to obtain the highest possible accuracy for brain treatments. Non-invasive and pain-free radiosurgical treatment is now available to patients. In addition, if feasible, the treatment can be divided into several stages,2 which makes it even safer to treat larger lesions or those in highly sensitive areas. Apart from standard neurosurgical indications (i.e. acoustic neurinomas, meningeomas, brain metastases), radiosurgical applications are currently evolving to include extracranial indications. It is now possible to treat tumours of the spine, pancreas, lung and liver safely and effectively with radiosurgical techniques in cases where the tumours are well delineated from the surrounding healthy tissue. In selected cases, this could replace a surgical procedure. Because of the physiological breathdependent organ movement, until now it has not been possible to apply high-radiation doses to body lesions. The newest development in Cyberknife radiosurgery is a breath-triggered realtime movement-correction system, which makes it possible to apply radiosurgical doses to these lesions. The Cyberknife moves according to the tumour’s movement. Infrared cameras follow the breath excursions and send information online to a robot, which steers the linac into position.6 Anaesthesia or dedicated body stereotactic frames, as used with conventional radiation devices to suppress respiration, are no longer necessary. Cyberknife treatment is designed for outpatient treatment, which significantly enhances the quality of life of cancer patients. A hospital stay or rehabilitation is not needed in most cases. Treatment time is dependent on tumour location and size and the organs at risk. A full course of radiosurgery lasts between 60 and 90 minutes.
