Non-Fourier heat conduction effect on laser-induced thermal damage in biological tissues

To ensure personal safety and improve treatment efficiency in laser medical applications, one of the most important issues is to understand and accurately assess laser-induced thermal damage to biological tissues. Biological tissues generally consist of nonhomogeneous inner structures, in which heat flux equilibrates to the imposed temperature gradient via a relaxation phenomenon characterized by a thermal relaxation time. Therefore, it is naturally expected that assessment of thermal damage to tissues could be inaccurate when a classical bioheat conduction model is employed. However, little attention has been given to studying the impact of the bioheat non-Fourier effect. In this article, a thermal wave model of bioheat transfer, together with a seven-flux model for light propagation and a rate process equation for tissue damage, is presented to investigate thermal damage in biological tissues. It is shown that the thermal damage assessed with the thermal wave bioheat model may differ significantly from that assessed with the classical bioheat model. Without including the bioheat non-Fourier effect, the assessment of thermal damage to biological tissue may not be reliable.