Photodynamic therapy (PDT) is a light-catalyzed process that can initiate cellular death pathways from the formation of cytotoxic reactive oxygen species at sub-cellular sites. Apoptosis was the first such pathway to be identified. Autophagy can also occur and is often found to be cytoprotective. Another process termed paraptosis can also have lethal consequences, even in cells with an impaired apoptotic pathway. PDT in vivo can evoke other potentially cytotoxic processes including vascular shutdown and enhanced immunologic recognition of neoplastic cells. Using appropriate photosensitizing agents, sub-cellular PDT targeting can be directed so that the resulting interplay among assorted death and survival pathways will result in an enhanced level of photokilling.

光动力疗法 (PDT) 是一种光催化过程，可以通过在亚细胞位点形成细胞毒性活性氧物质来启动细胞死亡途径。细胞凋亡是第一个被鉴定的此类途径。自噬也可能发生，并且经常被发现具有细胞保护作用。即使在细胞凋亡途径受损的细胞中，另一个称为细胞凋亡的过程也可能产生致命的后果。体内 PDT 可以引起其他潜在的细胞毒性过程，包括血管关闭和增强对肿瘤细胞的免疫识别。使用适当的光敏剂，可以定向亚细胞 PDT 靶向，从而导致各种死亡和生存途径之间的相互作用将导致光杀伤水平的提高。