Robot arm targets tumours

A robotic arm armed wielding high-intensity radiation that can target tumours which move with breathing has proven effective in treating lung cancer.



In trials, medical physicist Cihat Ozhasoglu of the University of Pittsburgh Medical Center has managed to eradicate tumours in some patients after 3-4 months of treatment using the arm. Although it is too early to determine the technique’s long-term effectiveness, Ozhasoglu and his colleagues believe the new approach holds promise for the future treatment of lung cancer and other tumours that move during breathing.



Ozhasoglu heads a team working with the CyberKnife, a radiation delivery system manufactured by Accuray, that uses a precise robotic arm designed to aim highly focused X-ray beams at the site of a tumour. There are currently 76 active CyberKnife sites worldwide, and an additional 62 scheduled to be installed globally.



Recently, the Pittsburgh researchers upgraded their CyberKnife by adding a system called “Synchrony,” which accurately targets tumours that move as a result of breathing. Synchrony instructs the robotic arm to move the radiation source, a linear accelerator that produces X-rays, in synchronisation with the tumour motion.



Using this technique, the researchers have established methods for the safe treatment of lung tumours which otherwise could not be treated with a high dose of radiation. Treating lung tumours with the enhanced Cyberknife requires only 1-3 sessions lasting 60-90 minutes. In conventional radiotherapy, patients must endure dozens of radiation treatments, each lasting about 15 minutes but requiring 20-30 hospital visits.



In a single treatment, Cyberknife blasts a lung tumour from all sides by delivering typically 100-150 intense, focused X-ray beams, causing the tumour to absorb approximately 10 times more radiation than in a conventional radiotherapy session. Cyberknife can deliver much more radiation than other techniques because its robotic arm aims the X-rays precisely enough to avoid surrounding healthy tissue.