Investigation of non-Fourier effects in bio-tissues during laser assisted photothermal therapy

The success of laser hyperthermia in the treatment of cancer depends on the extent of heat diffusion to the cancerous tissue. Understanding and optimising hyperthermia treatment requires accurate measurement and control of temperature distribution. This paper reports experimental and theoretical results of surface temperature distribution and thermal lagging effect in tissue-mimics during laser irradiation. Experiments are conducted on bio-tissue mimics embedded with and without gold nanostructures irradiated by a continuous wave diode-pumped solid state laser having wavelength of 1064 nm. The experimental results of surface temperature distribution are compared with the computational prediction, obtained by solving numerically the Pennes bio-heat transfer based on classical Fourier model and on the dual phase lag model. Based on the multiple scattering phenomenon a new model for the laser attenuation in tissues is proposed. It compares well with the experimental data. In addition, the qualitative nature of damage to bio-tissue upon laser irradiation has been examined experimentally using atomic force microscopy to demonstrate the denaturation potential of the surface temperature, when gold nanostructures are used to mitigate temperature rise.