To prevent a false irradiation to the surrounding urotherial tissue during stones laser fragmentation, we applied a new method, fiber-optic pulsed photo-thermal radiometry (PPTR), to discriminate between them. The experiments were made in vitro with wet stones and canine urotherial tissues irradiated by various lasers. The Ge-Se-Te glass fiber was used as a detection line. The ultraviolet Ar laser irradiation carried out better result than CO laser iradiation for the discrimination of the wet sample. The canine urotherial tissue was able to be clearly differential from the wet stones by the measurement of the e-folding decay time from the peak of the PPTR waveform.
