An Study on Laser Propagation Characteristics of Skin in Vivo

Laser has been used clinically as a therapeutic tool for at least twenty years and has achieved good clinical results. An understanding of optical properties of tissue is important for these applications. However, applying the rigorous electromagnetic theory to analyze light propagation in tissue is almost impossible. Therefore, several approximate analysis approaches to model the light propagation in tissue were introduced. In this study we tried to measure the power of diffuse light on body surface non-invasively and brought the data into comparison. Five positions which the superficial tissues are different were selected and Automation Control Technology was used to improve measurement efficiency and accuracy. Our study suggests that the distributions of diffuse light along different paths on the surface of skin are conformed to exponential attenuation law but the attenuation coefficients are different. Otherwise, the exponential attenuation coefficient of the same position is also influenced by the gender of subject.