It costs only about 30,000 yuan (US$3,600), much less than the 600,000 yuan needed to buy a similar instrument from Israel, said Gao Jianping, an associate professor at the institute who led the research team.

The invention, Gao said, means China will not have to be dependent on foreign imports for lasers that can be used more widely - inside the mouth and not difficult to reach organs that straight-line lasers cannot reach.

Tao Changzhong, deputy director of Shanghai Changzheng Hospital's dentistry department, which is testing the new invention, said: "The Chinese 'bendable' laser scalpel will surely become excellent medical equipment for dental operations, causing less bleeding and pain."

The bendable laser was first invented by Japanese scientists in the late 1980s.

Funded by a grant of 1.5 million yuan from the Ministry of Science and Technology, researchers spent the past five years trying to make silver halide, a chemical compound of a halogen with a more electro-positive element, into optical cable - the "soft pipelines" that direct laser beams to go to a desired location.

Because light travels in a straight line, earlier laser scalpels can only be applied to surfaces.

"The toughest challenge we faced was to find an adequate material to form the optical fiber. It took us five of our 10 years of re-search," Gao said.

He also said that since quartz optical-fiber, which is widely used in facsimile transmission, absorbs inter-mediate infrared - the basic light that forms a laser beam that is needed in operations - they had to use another material, which turned out to be silver halide because it's transparent to light.

(eastday 08/08/2001)