Perspectives on the Role of Photodynamic Therapy in the Treatment of Pancreatic Cancer

Figure 2

Mechanisms leading to the formation of ROS. There are two types of reactions during PDT. In Type I reaction, the triplet photosensitizer reacts with the neighboring substrate and forms free radicals as well as radical ions, which further interact with molecular oxygen and produce ROS. In Type II reaction, the triplet photosensitizer transfers its energy directly to molecular oxygen and form excited-state singlet oxygen.