RESUMO
The pulsed dye laser(Technomed pulsolith) with a wave-length of 504nm was irradiated directly in vitro on four human ureters which were obtained by ureteronephrectomy. The irradiation was at 5Hz with a pulse energy of 40 to 100mJ and total pulse count of 200 to 1000. Immediately after irradiation, the ureteral tissues were fixed with formalin solution and H&E stain. The extent of tissue damage was examined with light microscope. In this experimental study, we observed that mucosal damage occurred from pulse energy of 60mJ, total pulse rate of 600 and submucosal damage occurred from pulse energy of 80mJ, total pulse rate of 800. But We believed that the pulsed dye laser was safe because most stones were fragmented at less than a pulse energy of 80mJ, a total pulse rate of 800, and the ureter was irradiated indirectly during laser lithotripsy.