Research On Biological Effects In LED Radiation And Design Of The Therapy System

Based on the mechanism of biological effects of low intensity laser, a new therapy light source, light emitting diode, is presented to displace Lasers in following field: wound and acupoints healing, the temporary relief of pain, and Photodynamic Therapy. The advantages of light emitting diode on light intensity, the span of wavelength and low price are discussed. Based on these analyses, the project of LED employed as new type therapy source is feasible. A therapy system based on LED is designed, and the clinical results are presented finally. The main contents are as follows: (1) The interaction mechanism of LED and tissue is analyzed, and LED can bring forth the same biological effects as the laser does. The interaction of monochromatic light with cells is non-resonant for photobiomodulation. Consequently, the conclusion that photobiomodulation on tissue and cells do not require the light source which has very narrow waveband is found. Therefore, LED can be applied to generate photobiomodulation effects. Compared with laser, LED has advantage in this aspect. (2) The actuality and evolution trend of LED technologies are introduced. According to introducing the development of semiconductor technologies, especially the achievements in extra bright LED research, we consider that LED is more suitable to be light source in therapy system than laser because of LED's advantages in such aspects: light intensity, waveband and lifetime. (3) A therapy system used in dermatology is designed. The LED array, main circuit of the system and the system-control software are designed in details. (4) The system is applied in dermatology clinic. It is demonstrated that fibroblast activity could be regulated using LED light source. Procollagen synthesis could be upregulated in human skin fibroblast culture by varying fluence and other irradiation parameters. The clinical results are in accordance with the theoretical analyses.