RECENT ADVANCES IN PHOTODYNAMIC THERAPY

Photodynamic therapy is a relatively new clinical modality consisting of systemic administration of a photosensitizing dye that is preferent ially retained by tumors. Photodamage occurs when the sensitized tissu e is irradiated with light at a wavelength corresponding to the absorp tion bands of the photosensitizer. The result is a highly selective fo rm of tumor eradication. A review of the literature indicates that a v ariety of veterinary tumors can be effectively treated with photodynam ic therapy. Minimum toxicity has been noted, This technique does not s eem to share cross-resistance with other treatment modalities and can be repeatedly administered without additive toxic effects. Its potenti al for diagnostic imaging is also promising.