Infrared fiber optic radiometry analysis to prevent tissue injuries during endourological laser therapy

To prevent a false laser irradiation to an urotherial tissue during the laser stone fragmentation, we applied the fiber-optic pulsed photothermal radiometry (PPTR) to discrimination between urinary stones and urotherial tissues. The experiment was made in vitro with the various wet sample of the urinary stones and the canine urotherial tissues. Three different lasers, ultraviolet argon laser(UV Ar laser), visible argon laser(Vis. Ar laser) and carbon monoxide laser(CO laser), were used for excitation light sources of the PF'TR method and compared to obtain clear discrimination between the stones and the tissue. The UV Ar laser gave the best result among them. The wet canine urotherial tissue was clearly differential from the urinary stones by the measurement of the e-folding decay time of the PPTR waveform.