Dependence of laser-induced tissue ablation on optical fiber movements for laser prostatectomy.

Abstract

The aim of the current study was to identify the efficient fiber movements for 532-nm laser prostatectomy. 532-nm Lithium triborate (LBO) laser light was tested on 120 kidney tissues at three different translational speeds (TS 1, 2, and 4mm/s) and four different rotational speeds (RS 0.5, 1.0, 1.6, and 2.1rad/s). The applied power was 120W at a 2-mm working distance and 60° sweeping angle. Ablation rate and dimensions of resulting ablation craters were measured. Slower TSs and RSs created deeper and wider ablation craters with thinner coagulation, leading to more efficient ablation performance. Maximal ablation rate was achieved at a TS of 2mm/s and RSs of 0.5 and 1.0rad/s. An RS of 0.5rad/s accompanied surface carbonization for all the TSs. Irrespective of TS, ablation rate became saturated at faster RSs than 1.0rad/s. Faster TSs or RSs reduced tissue ablation, but increased thermal coagulation due to a shorter interaction time. Optimal ablation efficiency occurred at a TS of 2mm/s and a RS of 1.0rad/s with a thin coagulation of around 1.0mm and no or minimal carbonization. Further studies will validate the current findings with prostate tissue and high-power levels for laser prostatectomy.