Cyberknife

CyberKnife is the U.S. manufacturer Accuray manufacturer's designation for its robotic linear accelerator for radiosurgery, which was developed at Stanford University. According to the manufacturer until 2010 234 CyberKnife systems have been installed worldwide. In Germany there are eight systems (October 2012). Worldwide over 100,000 treatments were already performed with the CyberKnife System.

Construction

As radiation source is a linear accelerator. The length of the jet is 50 cm with a weight of 150 kg. The nominal dose rate of 6 Gy / minute in the reference distance of 80 cm. It produces photons of nominal energy 6 MeV; this energy corresponds to the body tissue to a dose decrease to 80 % after 6.7 cm. The relative biological effectiveness of these relatively low acceleration energy is estimated to be 1. The beam is expanded by a stray cones on field sizes of 5-60 mm. The linear accelerator is mounted on a conventional six -axis industrial robots. The positioning accuracy of the robot is specified by the manufacturer with 0.2 mm. A second robotic arm supporting the patient table. Media reports indicate the purchase price of 6 million U.S. dollars.

The system is continuously tracked during therapy and therefore comes without the usual radiosurgery securely to the patient bolted fixing frame from. The tracking system consists of two X-ray and an image processing computer. The axes of the two X-ray tubes are perpendicular and intersect at the center of the target area. The system thus provides a stereoscopic image. This image is compared with images reconstructed from the planning computed tomography. The position of distinctive bony structures or implanted gold markers must match. Displacements and rotations with respect to the reference position are supplied as a correction value to the robot.

The treatment planning software takes into account the particular irradiation geometry and uses an inverse algorithm with ray-tracing or Monte Carlo simulations. The treatment time is - depending on the complexity of the target volume - between 30 and 120 minutes.

Range of treatments

• Choroidal melanomas, acoustic neuromas, meningiomas, arteriovenous malformations, brain metastases, trigeminal neuralgia
• Metastases, neuromas and meningiomas of the spine
• Bronchial carcinomas in early stages, lung metastases
• Hepatocellular carcinoma and liver metastases
• Selected prostate carcinoma

History of CyberKnife technology

Lars Leksell developed in 1951, Professor of Neurosurgery at the Karolinska Institute and the physicist Börje Larsson at the University of Uppsala in the so-called of them radiosurgery. In 1968, it installed the first prototype of the gamma knife in Stockholm. In 1972, the Leksell Elekta Instruments, which from now produced the gamma knife devices. 1987 John Adler developed after his return from Sweden, where he had worked for Leksell, the first CyberKnife at Stanford University in California, USA. In 1990, the company Accuray was founded in California in order to produce and develop these devices. 1999 approved the American FDA in the treatment of brain and skull tumors in the United States. 2000, the authorization was extended to tumors throughout the body. In 2002, the CyberKnife System has been approved in Europe for the treatment of tumors throughout the body. 2005 the FDA issued the dynamic positioning ( Synchrony respiratory tracking ) approval. This made it possible (for example, lung) vorherzuberechnen the movements of the patient or of certain organs in the treatment.

Locations in Germany

Since 2005 there is a system in Munich, since April 2010 in Soest, since November 2010 in Mecklenburg Gustrow, since September 2011, in Hamburg- Long Horn and Berlin in November 2011, in Cologne, in June 2012 in the University Hospital Frankfurt am Main since November 2012 on the grounds of the Helios Klinikum Erfurt, and since July 2013, the clinic at Eichert in Göppingen.