. >> gerhard klaus has spent his life developing a strategy explored how these beams can be energized to precisely target tumor cells while sparing the surrounding tissue. the technique has proven so effective that 90% of the patients recover. >> with the material around in general is at the end. though you can go somewhere in and do something at the end. it's like a knife which is at the end very sharp and in between you don't see it at all. >> particle beams work exceptionally well when they are treating tumors in parts of the body like the brain which can be held absolutely still. but many tumors appear in the body in areas like the lungs and the liver and they're continuously moving inside the patient. the machine tracks the movement of the tumor during therapy. they used a robot to emulate the movement of a lung tumor inside the patient's chest. the particle beam tracks the cancer and continues to produce a dose of radiation where it's needed. >> like in the setup here for example you could really see from the outside you could just follow the row boat movement -- robot movement