光敏剂特性影响光动力治疗鲜红斑痣的数学仿真研究

目的：通过建立光动力治疗鲜红斑痣中激光、光敏剂、氧的分布及其相互作用关系的数学模型，对表皮、真皮、血管中单线态氧的产生过程进行仿真，了解光敏剂的药代动力学和扩散特性对单线态氧产生的影响，进而了解光敏剂特性在光动力治疗鲜红斑痣中的作用和意义。方法：用’Monte Carlo方法描述光在组织中的分布；用药代动力学描述光敏剂在血管中的变化规律；用Fick定律描述光敏剂和氧在组织中的扩散和分布；用与氧含量有关的二级动力学描述光敏剂的漂白；用Lambert—Beer定律和单线态氧的量子产率来计算各层组织中单线态氧的产生。结果：光敏剂药代动力学的变化，使注射光敏剂后开始照光的时间对各层组织中单线态氧产量有明显的影响。光敏剂扩散特性的改变，对真皮和表皮中单线态氧的产生有较大影响，对血管中单线态氧的产生没有影响。结论：光敏剂的特性对光动力治疗鲜红斑痣有明显的影响，数学仿真能较全面地反应这种作用的特点和意义。

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.