A Study of the Influence of Photosensitizer Characteristic in Photodynamic Treatment on Port Wine Stains by Mathematical Simulation

Objective: Through establishing mathematical model of the distribution of laser,photosensitizer, oxygen and their interaction relationship, simulating the produce of singlet oxygen in vascular, epidermis and dermis, analyzing the effects of photosensitizer's pharmacokinetics and diffuse characteristic on the produce of singlet oxygen, explore the action and value of photosensitizer characteristic in photodynamic therapy on port wine stains. Methods: Formulate the distribution of laser by Monte Carlo model. Formulate the distribution of photosensitizer in vessels by pharmacokinetics. Formulate the diffuseness of photosensitizer and oxygen in tissues by the Fick's law. Formulate photobleaching by second order kinetic reaction including the content of oxygen in tissues. Calculate the produce of singlet oxygen in every tissue by the law of Lambert-Beer and quantum yields of singlet oxygen. Results: The time begining to radiate laser would obviously the influence production of singlet oxygen in different tissue layers by the reason of the change of photosensitizer pharmacokinetics. The change of photosensitizer diffuse characteristic have a great effect on the producing of singlet oxygen in epidermis and dermis, but no use in vessel. Conclusions: Photosensitizer characteristics have obvious effects on photodynamic therapy for port wine stains, and mathematical simulation could show those points and their values in the round.