INTERACTION OF HOLMIUM LASER-RADIATION AND CORTICAL BONE - ABLATION AND THERMAL-DAMAGE IN A TURBID MEDIUM

The ablation of cortical bone by holmium laser radiation is described by experimental values of the ablation rate, the depth of tissue damag e, and the tissue temperature. An ablation model is presented on the b asis of photon diffusion in a turbid medium. When this model is compar ed with experimental results for the ablation rate, the penetration de pth is determined. The expansion of the laser-induced heat can be expl ained by a point heat source located in a distance beneath the surface equal to the ablation depth. The accumulation of heat as a function o f the repetition rate of the laser leads to a limitation of the repeti tion rate. In order to avoid traumatic heat accumulation, a maximum re petition rate should not be exceeded. (C) 1997 Optical Society of Amer ica