Comparative analysis of repetitive pulsed and continuous laser heating in multi-layered skin: Bioheat vs. dual-phase lag model perspective

Precise thermal control is critical for safe and effective laser-based skin treatments. Existing studies often overlook the limitations of conventional heat transfer models, particularly when applied to repetitive pulsed laser exposure. This study addresses this gap by comparing the Bioheat and Dual-Phase Lag (DPL) models for predicting thermo-mechanical responses in multi-layered human skin. A validated one-dimensional computational framework was developed, incorporating light propagation, non-Fourier heat transfer, thermal damage via the Arrhenius model, and tissue deformation analysis. The model was rigorously validated against published data, demonstrating strong agreement with measured temperature profiles. Results indicate that repetitive pulsed laser irradiation generates sharper temperature gradients and higher transient thermal stress than continuous exposure, with the Bioheat model consistently overestimating surface temperatures (60.12 °C vs. 50.53 °C) and thermal damage, exceeding DPL predictions by up to three orders of magnitude. Likewise, Bioheat-based deformation and dermal stress were ∼0.4 mm (140%) and ∼0.29 MPa (126%) higher, respectively. These findings confirm that heat transfer assumptions critically influence temperature, damage, and mechanical predictions in laser-tissue interactions. Incorporating realistic models such as DPL is essential for optimizing laser protocols, improving treatment safety, and enhancing clinical outcomes in dermatology and biomedical applications.