Bioheat transfer analysis of biological tissues induced by laser irradiation

• The thermal response of biological tissues during laser irradiation is studied based on a generalized DPL model.
• The governing equation is analytically solved by employing the separation of variables and Duhamel's integral.
• The obtained results by the generalized DPL model are totally different with those obtained by the classical DPL model.
• The impacts of the blood flow, coupling factor and the time delay τT on the time history of temperature are similar.
• The generalized DPL model predicts the lower temperature than that of the classical DPL model.

This paper develops an analytical solution for a generalized dual phase lag (DPL) model based on the nonequilibrium heat transfer in biological tissues during laser irradiation achieved by performing volume average to the local instantaneous energy equation for blood and tissue. The obtained energy equation is solved by employing the separation of variables and Duhamel's integral method for both absorbing and scattering tissues. The generalized DPL model anticipates different results than that of the predicted by the classical DPL and Pennes bioheat transfer (parabolic) models. It is found that the generalized DPL model calculates lower temperature than that of obtained by the classical DPL model due to considering heat convection between blood vessels and tissue. The obtained analytical results are also compared with existing numerical and experimental data to verify the accuracy of the analytical solution. The results indicate that the generalized DPL model reduces to Pennes bioheat transfer model when both thermal lag times are zero. It is shown that effects of blood perfusion rate, coupling factor and the lag time τT on the temperature response of tissue are similar. Furthermore, the comparison between the analytical results and existed experimental data shows that the present mathematical model is an efficient tool for evaluation of bioheat transfer in biological tissues.