Analysis of Heat Affected Zone during Short Pulse Laser
Irradiation of Tumors
Current Sponsor: Raydiance Inc.
Past Sponsor: Food and Drug Administration
Use of short pulse laser for minimally invasive therapeutic treatment has become an indispensable tool in the technological arsenal of laser induced surgery and medicine. Over the last few years, short pulse lasers are increasingly being used in hyperthermia treatment of tumors resulting in ablation at the desired high temperature. The objective of this research is to study the temperature distribution and analyze the heat-affected zone in tissue media during short pulse laser irradiation of tumors and tumor models using a converging laser beam tightly focused directly at the tumor location. Experiments are first performed on homogeneous tissue phantoms for selection of optimal laser parameters. Next, the experiments are performed on tissue phantoms containing inhomogeneities with the laser beam focused both at the surface and at the inhomogeneity located underneath the surface. Radial and axial temperature distributions are recorded using a thermal imaging camera and thermocouples respectively. Traditionally Fourier heat conduction model, which implies an infinite speed of propagation of heat, is used to model such bio-heat transfer phenomena. In this research, a hyperbolic non-Fourier heat conduction formulation is used to study axial and radial temperature distributions in tissue medium and compared with the Fourier model. Experimentally measured temperature profiles match the prediction from the non-Fourier model compared to the Fourier formulation, particularly for times less than the relaxation time of tissues. Temperature distributions are strong functions of the focusing depth and of the properties of the embedded inhomogeneities. Finally, experiments are performed on live anaesthetized mice containing mammary tumors.
Pal, G., Dutta, A., Kulkarni, S., Mitra, K., and Grace, M., “Heat Affected Zone in Layered Tissue Phantom and Animal Model during Short Pulse Laser Irradiation of Tumors,” American Society for Laser Medicine and Surgery Annual Meeting, Boston (Massachusetts), April 5-7 (2006) [Selected for Student Travel Award].
Pal, G., Basu, S., Mitra, K., “Bio-heat Transfer in Layered Skin Model Subjected to Short Pulse Laser Irradiation,” American Society for Laser Medicine and Surgery Annual Meeting, Orlando (Florida), March 31-April 3 (2005) [Selected for Student Travel Award].
Banerjee, A., Ogale, A., Das, C., Mitra, K., and Subramanian, C.S., “ Temperature Distribution in Different Materials Due to Short Pulse Laser Irradi Heat Transfer Engineering, Vol. 26, No. 8 (2005).
Mitra, K., Kumar, S., Vedavarz, A., and Moallemi, M.K., " Experimental Evidence of Hyperbolic Heat Conduction Waves in Processed Meat,” ASME Journal of Heat Transfer, Vol. 117, No. 3, pp. 568-573 (1995).