Background: Investigating temperature changes and thermal distribution in the interaction of different lasers with various materials has always interested researchers. This study estimated thermal distribution and temperature change of skin, fat, and muscle tissue in interaction with different wavelengths of laser in laser therapy technique for repairing musculoskeletal injuries using COMSOL Multi-physics software.
Methods: A three-dimensional cube with separate layers and various thicknesses was determined, and then the optical and thermal parameters were determined for materials in different wavelengths. Bio-heat transfer physics in biological tissue was utilized to investigate thermal distribution. In addition, the energy radiated by the laser beam at different wavelengths was considered as a radiant heat source.
Results: The results of the calculations by the software showed that different wavelengths of the laser could change the skin temperature up to 38.8 degrees Celsius. However, no noticeable temperature changes were observed in deeper tissues such as muscle tissue.
Conclusion: In laser therapy methods for tissue repairing, photochemical phenomena are important, not thermal processes. In the present study, it was proven that temperature changes in tissues are not significant.