Photo-thermo-mechanical model for laser hair removal simulation using multiphysics coupling of light transport, heat transfer, and mechanical deformation (case study)

The mathematical model has become one of the tools for prediction to assist physicians and specialists with hair laser removal in dermatology. This paper proposes a model that comprehensively predicts optical, thermal, and mechanical responses within the skin during laser hair removal to determine optimal therapeutic conditions and prevent skin tissue damage. This research highlighted developing a mathematical model using multiple physics of light transport, heat transfer, and mechanical deformation. The present mathematical model is resolved using the 2D axisymmetric finite element method (FEM) with optical, thermal, and mechanical properties to characterize the laser intensity, temperature distribution, mechanical stress, and displacements within skin tissue. The comparison of the simulated results in laser wavelengths of 595 nm, 800 nm, and 1064 nm is also provided. The results revealed that laser deposition with skin tissue depends on the wavelength and optical diffusion coefficient. Applying the 1064 nm performs the best treatment outcome for hair laser removal. In contrast, 595 nm and 800 nm might lead to adverse pain sensations. The high temperature caused an increase in mechanical stress and displacement. The results of this study indicate that laser therapy has certain limitations that must be considered