Modeling of thermal effects in Er:YAG laser skin resurfacing

The influence of Er:YAG laser pulse fluence and duration on temperature profile development, coagulation depth and the ablation threshold in skin resurfacing is analyzed using an original 1D numerical model. The model is focused on the role of mechanical properties of the treated tissue, such as elastic modulus and tensile strength. It combines a thermodynamic model of overhead tissue water with the response of surrounding elastic medium to the resulting pressure increase. Diffusion of dissipated heat is treated in one dimension for the case of isolated tissue surface. Additionally, the nonlinear protein denaturation process is modeled as usual. The results show how the pulse duration influences the depth of heat-affected layer in mid-IR laser skin resurfacing.