PLASTIC HOLLOW WAVE-GUIDES - PROPERTIES AND POSSIBILITIES AS A FLEXIBLE RADIATION DELIVERY SYSTEM FOR CO2-LASER RADIATION

Background and Objectives: One significant inconvenience of the CO2 la ser is the lack of flexible fibers essential for endoscopic applicatio ns. The goal of this study is to test the feasibility of hollow wavegu ides in view of a practical use in medicine. Study Design/Materials an d Methods: Various types of plastic hollow waveguides for flexible del ivery of CO2 laser radiation were examined. The transmission losses, d ivergence angle, damage threshold, and input and output beam profiles were determined. The interaction process between radiation transmitted through these guides with soft as well as hard tissues was studied. R esults: Plastic hollow waveguides can transmit high power (up to 50 W) with low losses (straight guide 1 dB/m) even through bendings. The di vergence angle is < 13-degrees. Cutting quality and extent of thermal damage are comparable to incisions performed with a free laser beam. C onclusion: The results of this study show good cutting quality and dur ability of these flexible plastic hollow waveguides, which render poss ible to deliver CO2 radiation in the power range needed for most surgi cal applications with affordable transmission losses. Plastic hollow w aveguides are, therefore, a real alternative to replace the mirror arm s. (C) 1995 Wiley-Liss, Inc.