Investigation Of Thermal Effects On Tissues During Laser Applications

Abstract

With the development of technology, laser applications have become one of the important methods for the health sector. A better understanding of laser-tissue interaction can improve the effectiveness of treatment and diagnosis. Moreover, the usage of laser in the health sector can be expanded. However, laser application causes tissue to warm up. Undesirable conditions may be encountered during treatment or diagnosis if this warming does not fall within certain limits or if it cannot be maintained within the desired area / volume. With the help of mathematical models, this thermal effect which is experienced in laser tissue interactions can be calculated in advance. Thus, unwanted situations can be avoided.

In this study, a mathematical model was developed to understand the thermal effects of laser on tissues. This model is formed based on porous media theory. It is based on the fundamental energy equation and is derived as a macroscale model taking into account the mechanisms at the microscale. During the model derivation phase, tissue and blood were assumed to be under local thermal nonequilibrium conditions.

The developed model was solved using numerical methods. The solution was performed using MATLAB program. The obtained results were compared with Pennes and DPL model which are frequently used in literature. Differences between the results of the models were observed and the possible reasons of them were discussed. The effect of porosity and properties of laser irradiance on temperature was also investigated.