数学仿真研究光漂白对光动力治疗鲜红斑痣的影响

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,了解与光漂白有关的各种因素对单线态氧产生的影响,进而了解光漂白在光动力治疗鲜红斑痣中的作用和意义。方法用MonteCarlo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皮肤各层组织中单线态氧的产生。结果由于光漂白的作用,激光和光敏剂剂量的增加使血管壁单线态氧产量增加,比正常组织中多。光敏剂漂白特性的改变,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。结论数学仿真能较全面地描述光动力治疗鲜红斑痣中光漂白的作用和意义。

Influence of Photobleaching 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 generation of singlet oxygen in blood vessel, epidermis and dermis, analyzing the effects of various factors relating with photobleaching on the generation of singlet oxygen,to explore the action and value of photobleaching in photodynamic therapy on port wine stains. Methods The distribution of laser was formulated by Monte Carlo model.The distribution of photosensitizer in vessels by pharmacokinetics. The diffuseness of photosensitizer and oxygen in tissues was formulated by the Fick's law.The photobleaching was described by second order kinetic reaction including the content of oxygen in tissues. The generation of singlet oxygen in every tissue was calculated by the law of Lambert-Beer and quantum yields of singlet oxygen. Results The increase in singlet oxygen in vessel's wall was more than that in other normal tissues by the reason of photobleaching when the dose of laser or photosensitizer was increased. The change in photosensitizer bleaching characteristic had great effect on generation of singlet oxygen in epidermis and dermis, but no use in vessel. Conclusions Mathematical simulation could show whole aspects of photobleaching's action and value in photodynamic therapy on port wine stains.