An axisymmetric dual-phase-lag bioheat model for laser heating of living tissues

A two-dimensional (2D) axisymmetric dual-phase-lag (DPL) model is proposed to describe heat transfer in living biological tissues with nonhomogeneous inner structures. The DPL constitutive equation is incorporated, for the first time, into the 2D axisymmetric bioheat transfer model in living tissues, and corresponding numerical approach is developed. Two heating schemes (surface heating and body heating) and two beam profiles (flat beam and Gaussian beam) are examined in detail. The numerical results indicate that the DPL bioheat conduction model describes different thermal responses from the thermal-wave and Pennes' bioheat conduction models, depending on the values of the two lagging times. For a local heating with the heated spot smaller than the tissue bulk, the variations of the non-uniform distributions of temperature suggest that the multi-dimensional effects of thermal wave and diffusion not be negligible. It is also found that due to the presence of blood perfusion in living tissues, the present DPL bioheat conduction model reduces to the Pennes' bioheat model only when τq=τT=0.