Semi-Analytical Solution and Experimental Analysis of Laser-Irradiated Skin Tissue Using the Dual-Phase-Lag Bioheat Model

This study presents a semi-analytical framework for predicting three-dimensional transient temperature distributions in skin tissue exposed to Gaussian laser irradiation. The model integrates the dual-phase-lag (DPL) bioheat transfer theory with photothermal tissue response to address non-Fourier thermal conduction phenomena during transient processes. By accounting for phase-lags in both heat flux and temperature gradient, the DPL bioheat equation is innovatively solved by employing the method of separation of variables in combination with the Newton-Cotes numerical integration scheme. And experimental validation is conducted through ex vivo porcine skin tissue trials so as to demonstrate agreement between theoretical predictions and measured surface temperature profiles. In addition, a complementary finite element model incorporating phase-lag effects is developed in COMSOL Multiphysics to analyze spatial and temporal thermal responses. Comparative evaluations show that the DPL model captures thermal lag behavior more accurately than the classical Pennes model, with a 15% reduction in surface temperature prediction error in 70 experimental trials. Parametric investigations demonstrate that the phase-lag times of heat flux and temperature gradient influence the temperature field significantly, and the latter having a more pronounced effect. Moreover, blood perfusion rate and laser spot size are identified as critical control parameters, showing non-linear relationships with thermal penetration depth and transient heating rates.