Investigating the Dose Parameters of Low-Level Laser Therapy to Optimize Therapeutic Efficacy

Introduction Low-level laser therapy (LLLT), also known as photobiomodulation, has emerged as a promising therapeutic option for various medical applications, including pain management and wound healing. This study aims to investigate the dose parameters of LLLT to optimize therapeutic efficacy. Materials and Methods We utilized Finite Element Analysis within the COMSOL Multiphysics software package to model light-tissue interactions and refine dosing protocols. Lasers with wavelengths of 660 nm, 780 nm, and 808 nm were selected due to their widespread use in therapy. Additionally, we examined several factors that impact the effectiveness of the treatment. Key parameters considered include energy, energy density, power, power density, irradiation time, and tissue penetration depth. Results The recommended stimulation time should not exceed six minutes (480 seconds) at a power density of 15.62 mW/cm². However, if the power density is reduced to a maximum of 3.10 mW/cm 2 , the stimulation time can be safely extended to 10 minutes (600 seconds) without causing undesirable thermal effects, as long as the tissue temperature does not exceed 40°C during the extended stimulation. It is important to note that the dose applied to the surface of the tissue significantly decreases as it penetrates deeper. The average energy loss is approximately 11% per millimetre of tissue. Our simulations indicate that effective doses range from 0.38 J/cm² to 9.37 J/cm² while maintaining safe tissue temperatures, which are consistent with WALT recommendations. Conclusion Our findings help identify factors influencing stimulation, guiding therapists to standardize treatment parameters such as wavelength, exposure time, and dosages measured in joules, watts, W/cm², and J/cm² for consistency and safety across studies.