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Photodynamic therapy (PDT) is a relatively new treatment modality. Clinical PDT procedure involves the administration of a photosensitizer followed by local illumination with visible light of a specific wavelength. In the presence of molecule oxygen, the light illumination of photosensitizer can lead to a series of photochemical reactions and consequently generate a variety of cytotoxic species.The nature, location and quantity of PDT-induced cytotoxic species and the sensitivity of the target cells determine the outcome of a PDT treatment.Since the first govment approval of photosensitizer Photofrin was granted, for the treatment of bladder cancer in Canada in 1993,1 the utilization of PDT in the treatment of malignant and non-malignant diseases has increased significantly due to the improvement in photosensitizers and light applicators. Several similar photosensitizers have been developed and utilization in China since the 1980s.2