Laser fragmentation of urinary calculi. In vitro studies

Parameters for effective in vitro laser fragmentation of urinary calculi by the neodynium-YAG (Nd:YAG) laser and the KrF-Excimer laser are examined. The results of reflection measurement of urinary calculi at wavelengths of different laser systems are presented. From lambda = 1046 nm (Nd:YAG laser) to lambda = 249 nm (KrF-Excimer laser) a continuous decline of reflection is found. The reflection at lambda = 1046 nm is above 90% whereas a complete absorption is found in the ultraviolet range. Furthermore a tube which contains as essential parts a water pump and a Nd:YAG laser system is presented. This tube allows by determination of its entrance size and by sucking off the urinary calculi fragmentation to particles which are not larger in diameter than the entrance size. Following these results experimental data with the KrF-Excimer laser are presented.