Photodynamic therapy in gastroenterology: Current status in the year 2000

Photodynamic therapy (PDT) involves the interaction between a photosensitiz ing agent and light, in the presence of oxygen, to produce photodamage to t arget tissue, While photodynamic therapy has been used since ancient times to treat dermatoses, it was not until the 1960s that porphyrin-based photos ensitizers were first used for photodetection and phototherapy of malignanc ies, Thereafter, clinical experience accumulated slowly until the mid-1990s , when regulatory approval for PDT using porfimer sodium was granted in par ts of North America, Europe, and Japan. This paper reviews recent clinical advances and discusses technological developments that may soon alter the w ay in which photodynamic therapy is used.