How does Cyberknife work?
Cyberknife combines three different technologies that work hand in hand and thus enable very precise radiation of tumors.
This generates high-energy photon beams (X-rays) and directs them onto the tumor from many different directions in space. The rays hit the cancerous tissue in bundled form, overlap there, develop their effect in a targeted manner and thus switch off the tumor – this can be compared to a “crossfire” that the cancer focus gets into.
Every single beam in itself would be too weak to harm the tumor. But taken together, the rays develop an enormous impact force. The surrounding healthy tissue receives only a small part of the radiation energy and can therefore be largely spared.
The photon emitter is attached to a robot arm that has several joints and can therefore be flexibly controlled. The robot has various safety systems so that it does not come too close to the patient during the irradiation.
Computer-controlled image location system and dynamic position correction
Cyberknife has a special image location system. This consists of two X-ray tubes on the ceiling and two image detectors located in the floor. In this way, structures and organs can be precisely located in space.
In addition, the position of the robot can be adjusted dynamically. During the irradiation, patients have LEDs on their upper body, the movements of which are recorded by a camera. During the Cyberknife treatment, the system tracks and corrects all of the patient’s movements in real time. It continuously produces new X-ray images and compares them with the original images from the computer tomography. The system can calculate deviations and compensate for movements of the tumor, for example when a patient is breathing (breathing compensation). The system synchronizes both pieces of information – the tumor position and the breathing movement – and then creates a model of the tumor movement.