On the Hyper Thermal Therapy of Tumor Tissues by Direct Laser Heating and Gold Nano Particles

Abstract

Hyper thermal therapy using lasers is emerging as a new promising route for the cancer treatment. The tumor can be directly heated by the radiation or indirectly using gold nano particles based on plasmon resonance phe nolmenon. These two possibilities are explored here by solving the space and time dependent bio - heat equation under different conditions. The knowledge of temperature profiles in the tumor region helps to bypass the pain ful placement of sensors for monitoring tumor’s heating by the laser. Important properties which could be useful for developing an efficient tumor therapy are introduced for the first time. It is found that the effects of metabol ism consist essentially in a redefinition of the blood temperature which increases proportional to the heat of me tabolism. Blood perfusion in a given tissue leads to a new characteristic length of order one or two centimeters and a blood convection parameter typically of order 30 W · m -1 · K -1 . Effects of these parameters are scrutinized within the resolution of the bio - heat equation under a variety of conditions. In general, space modulations of the temperature throughout biological tissues are weak but front kinetics are quite fast. Specific examples show the way to monitor the temperature rise taking into account the tumor’s nature and size.