THE DESIGN OF A PDT-LED LIGHTING SOURCE CONTROLLED BY SCM

摘要

Photodynamic therapy (PDT) is a promising new method for cancer, which damages healthy tissue significantly less than other methods. The most popularly accepted light source is laser, while the rapid development of LED provides a much better choice for superficial lesions. Our group has been working to develop a new PDT light source of LED array, with the regulable parameters: irradiation power, time for irradiation and intermission. The irradiation power of LED is regulated with PWM using the relatively high frequency output by SCM. The relatively low frequency outputs use the time of up levels to regular the time of irradiation while the time of low levels to regular that of intermission. The light sources that we designed are tested with a light-intensity distributing apparatus to learn about the effectiveness of PWM. The consequences prove a pro rata relationship between photocurrent and duty-ratio. We also take experiments of PDT with human hepatocellular carcinoma cell line HepG2, and justify the validity of our design by the inhibition ratio shown in MTT.