Alteration of laser-tissue interaction with the 805 nm diode laser using indocyanine green in the canine prostate

Background and Objective: Research interests in laser prostatectomy continue to evaluate a variety of wavelengths and treatment parameters in an effort to optimize treatment. Recently, a semiconductor diode laser with a wavelength of 805 nn has become available for clinical use; however, free-beam noncontact applications were limited by the low power output (25 W). In this study in the canine prostate, the possible potentiating effects of intravenously administered indocyanine green (ICG) were evaluated with the 805 nm diode laser. Study Design/Materials and Methods: A total of 16 fixed position, free-beam lasings were performed at 25 W for 60 sec in four dogs with eight lasings before and eight lasings after ICG administration Endoscopic observations and measurements of lesion volumes were used to evaluate the laser-tissue interactions. Results: Prior to ICG administration, we observed that side fire irradiation produced primarily small coagulative lesions. Following ICG administration, however, immediate and more noticeable tissue vaporization occurred, although total lesion size was not increased. Pathologic review demonstrated less coagulation and hyperemia, but a larger vaporized cavity in the ICG treated tissue. Conclusion: These findings suggest intravenous ICG alters laser-tissue interaction with the 805 nn diode laser in the canine prostate. The use of the 805 nn diode laser with enhancing chromophores deserves further investigation. (C) 1996 Wiley-Liss, Inc.