Application of Lower Fluence Rate for Less Microvasculature Damage During Tumor Photodynamic Therapy

摘要

To study the role of the fluence rate of the illuminating light in the photodynamic therapy (PDT), an in vivo experiment is made, which focuses on the influence of light fluence rate on the microvasculature damage. The microvasculature damage is studied through observing the values of RBCs column diameter during the process of the HpD mediated PDT. It is found that less microvasculature damage is induced by 75 mW/cm~2 illumination than that by 150 mW/cm~2, to some extent, which can be used to explain the conclusions of some other studies that under 75 mW/cm~2 illumination tumor oxygen can be better preserved than 150 mW/cm~2. The vessels histology study is performed at the end of PDT and vessels damage can be seen in both groups (75 mW/cm~2 and 150 mW/cm~2). That indicates microvasculature will eventually be destroyed only if the administration of light fluence is enough, regardless of the illuminating fluence rates. Thus microvasculature damage induced by low fluence rate illumination can also do well in the tumor control after PDT.