Analysis of Heat Affected Zone During Short Pulse Laser Irradiation of Tumors

The objective of this study is to analyze the heat-affected zone in tissue phantoms containing inhomogeneities and skin tumors in live anaesthetized rats when irradiated with a focused beam from a short pulse laser source. Tumors are simulated with the inhomogeneities embedded inside the tissue phantoms with different combinations of optical and thermo-physical properties with respect to the base tissue matrix. Experiments are also performed on anaesthetized rats with tumorogenic agent injected below and on the skin. The experiments performed demonstrate that short-pulsed laser heating results in a higher peak temperature rise with a lower heat affected zone compared to a continuous wave source. Hyperbolic non-Fourier heat conduction formulation is used to study axial and radial temperature distributions in tissue medium. Experimentally measured temperature profiles match extremely well with the prediction from the non-Fourier model than the Fourier formulation, particularly for time less than the relaxation time of tissues.