Future of Photodynamic Therapy for Diagnosis and Treatment of Malignant Tumors

Abstract

Since 1978, our groups have synthesized more than 700 kinds of porphyrin derivatives and studied the mechanism of tumor tissue affinity and photodynamic therapy. Recently our studies suggest that tumor tissue affinity of porphyrin is based on specific physico-chemical properties of porphyrin and lack or imcompleteness of lymphatic system in cancer tissue.
The importance of triplet life time of porphyrins was reported and we can estimate the capacity of singlet oxygen production of each sensitizer. The absorption wave length of future photosensitizer may be 670-700nm. Two photon excitation method is practically expected not to be effective in PDT.