Preliminary evaluation of a pulsed 2.15-micron laser system for fiberoptic endoscopic surgery

There is a need for lasers that are compatible with fiberoptic endoscopes and that provide greater cutting precision than currently can be produced by the widely used Nd:YAG (1.06 micron) laser. Recently available lasers that operate in the 2-micron region fill this need. This laser light energy can be transmitted by low OH- silica fibers and has much less tissue penetration than radiation at 1.06 micron. We have been evaluating a prototype solid state laser system that produces pulses of 2.15 microns light that is delivered by a silica based fiberoptic delivery system with negligible transmission losses. This system is based on a thulium-holmium-chromium doped YAG (Tm-Ho-Cr: YAG) rod that lases at 2.15 micron. The laser does not require cryogenic cooling, toxic gases, or custom utilities and should be practical in a clinical environment. In vivo animal testing of this laser confirms that it provides greater ablating precision than does the Nd:YAG laser at 1.06 micron.