Comparison of Photodynamic Therapy Using a Green or Red Light-Emitting Diode with Computer Simulation

Abstract

We compared the effi cacies of photodynamic therapy (PDT) with a light-emitting diode (LED) at the green or red wavelength region using a computational simulation model with the Monte Carlo method and a theoretical estimation based on quantum chemistry. The amount of singlet oxygen produced by a green or red LED was comparable with that produced by a green or red laser, respectively, and that produced by the green LED with a peak emission wavelength of 515 nm exceeded that produced by the red LED with a peak emission wavelength of 629 nm within a depth of about 2 mm. We infer that PDT with a green LED is effective for cancers localized around such tissue surfaces as the intraepithelial carcinoma of the bladder.