THE EFFECT OF POPCORN AND CARBONIZATION ON NEODYMIUM - YAG LASER DOSIMETRY IN THE CANINE MODEL

Neodymium:YAC laser irradiation of the canine prostate provides an exp erimental model for the study of the laser-tissue interaction in laser prostatectomy. Prostate irradiation was undertaken using right-angle- firing laser fibers through an open suprapubic cystotomy, and the proc edure was monitored by video endoscopy via a perineal urethrostomy. Th e effects of popcorn and surface carbonization on intraprostatic heati ng profiles were determined by interstitial thermometry. We found that popcorn reduced intraprostatic temperatures but that continued irradi ation resulted in the restoration of heating, Carbonization resulted i n the loss of heating ability deep in the prostate. These observations allow the urologist to understand the thermal implications of observe d surface change and to modify lasing parameters during surgery to obt ain the desired laser-tissue interaction.