Analyzing Two Laser Thermal Energy Calculation Equations: A Comparison of Beer-Lambert's Law and Light Transport Equation

Jedsadakorn Saemathong1

Nattadon Pannucharoenwong1, Email

Vannakorn Mongkol1

Somsak Vongpradubchai1

Phadungsak Rattanadecho1

Center of Excellence in Electromagnetic Energy Utilization in Engineering (CEEE), Department of Mechanical Engineering, Faculty of Engineering, Thammasat School of Engineering, Thammasat University, 12120, Thailand.

Abstract

An estimated 2-3 million skin cancers are occurring worldwide each year, most of which are caused by UV exposure. Therefore, many methods of prevention and treatment are required. As a result, a new technique for treatment, such as the use of laser treatment, has been proposed to study through mathematical models because human studies have ethical limitations. Previously, the laser power was calculated using two of the most widely used laser equations: Beer-lambert's law (BLL) and light transport equation (LTE). In this work, the temperature distribution from the two equations was studied and compared, and the effect of skin thickness is also being investigated.  The study found that in the model, the thickness of the thin epidermis at low wavelengths was slightly different and interchangeable. However, the Light Transport Equation model has a higher depth temperature distribution at high wavelengths 800 and 980 nm in thin and thick models. There was a clear difference in temperature distribution in the simulations exposed to high-wavelength laser radiation. Furthermore, the laser beam radius and fluency rate impact the temperature distribution in the same way, i.e., as the calculated model temperature parameter increases. The radial temperature distribution increases as the laser beam radius increases.

Analyzing Two Laser Thermal Energy Calculation Equations: A Comparison of Beer-Lambert's Law and Light Transport Equation