Enhancing laser therapy procedure through surface temperature control in multi-layered skin tissue

Laser therapy is extensively utilized in dermatology and medicine due to its ability to precisely target tissues, particularly for skin rejuvenation and colla-gen stimulation. However, the complex interactions between laser irradiation and multilayered skin structures remain insufficiently understood. This study presents a two-dimensional dual-phase-lag heat conduction model to simu-late the temperature distribution in multilayered skin subjected to pulsating laser irradiation. The model incorporates the distinct optical and thermal properties of different skin layers, enhancing the accuracy of heat transfer analysis. To regulate laser intensity and maintain surface temperature within a predefined range, a proportional-integral-derivative (PID) control system is implemented. Experimental validation using an agar-based phantom shows strong agreement with simulation results, confirming the model's reliability. The results further indicate that the PID control system effectively maintains the target temperature with minimal overshoot. However, while surface temperature remains regulated, deeper skin layers may experience higher peak temperatures, emphasizing the need for improved subsurface thermal monitoring, particularly in high absorption treatments. Additionally, the study systematically analyzes the influence of PID gain parameters on temperature regulation, highlighting their impact on system stability and response time. These findings underscore the critical role of integrated control systems in laser-based thermal therapies, enhancing precision, safety, and clinical efficacy. The proposed framework provides a robust foundation for real-time temperature management, contributing to more reliable and effective medical applications of laser technology.