1997 Volume 88 Issue 10 Pages 885-891
(Background) We report basic animal experimental study which we evaluated the thermocoagulation effects of two different type of Nd: YAG laser (pulse and continuous wave (CW) laser).
(Methods) The Rotalase internally reflecting fiber delivery system coupled to the pulse and CW Nd: YAG laser was used to create lesions in Seminoma tissue implanted Scid mice with the fiber tip 2mm away from the target tissue under the water. Laser power output used was 20, 40 and 60-watt for varying times (30-180sec) of irradiation. Stationary lesions, where a single spot of target was irradiated, were created. On the other hand, we measured tissue temperatures at 7, 10 and 14mm from tissue surface. The seminoma tissues removed from Scid mice were photographed after bisection, the fixed in 10% formalin and examined histologically.
(Results) For the purpose of these experiments, ablated tissue is defined as the volume of tissue that has been destroyed by both coagulation and vaporization. Estimates of the volume of ablated tissue were made by macroscopic examintion of the bisected lesion, measuring the depth and width of the lesion as seen from the edges of the coagulated area around vaporized zone. The mean depth and width penetration, volume ablation and rising of the tissue temperature at pulsed 60-watt, 60 seconds was greater than that observed at other groups. Irradiated spot lesions were characterized by an initial 10-20 second period of tissue blanching followed by an audible “popcorn phenomenon” which meant more than 100°C in tissue temperature, then formation of small surface bubbles as tissue began to evaporate and char.
(Conclusion) This study suggests the potential usefulness of the pulse Nd: YAG laser for Visual Laser Ablation of the Prostate (VLAP).