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 co ntinue to evaluate a variety of wavelengths and treatment parameters i n an effort to optimize treatment. Recently, a semiconductor diode las er with a wavelength of 805 nn has become available for clinical use; however, free-beam noncontact applications were limited by the low pow er output (25 W). In this study in the canine prostate, the possible p otentiating effects of intravenously administered indocyanine green (I CG) were evaluated with the 805 nm diode laser. Study Design/Materials and Methods: A total of 16 fixed position, free-beam lasings were per formed at 25 W for 60 sec in four dogs with eight lasings before and e ight lasings after ICG administration Endoscopic observations and meas urements of lesion volumes were used to evaluate the laser-tissue inte ractions. Results: Prior to ICG administration, we observed that side fire irradiation produced primarily small coagulative lesions. Followi ng ICG administration, however, immediate and more noticeable tissue v aporization occurred, although total lesion size was not increased. Pa thologic review demonstrated less coagulation and hyperemia, but a lar ger vaporized cavity in the ICG treated tissue. Conclusion: These find ings 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.