ABSTRACT
Photodynamic therapy (PDT) is a clinical treatment that combines the effects of visible light irradiation with subsequent biochemical events that arise from the presence of a photosensitizing drug (possessing no dark toxicity) to cause destruction of selected cells (Gannon and Brown 1999). The photosensitizer, when introduced into the body, accumulates in the target cells and a measured light dose of appropriate wavelength is then used to irradiate the target tissue (De Rosa and Bentley 2000; Peng et al. 1997). This activates the drug through a series of electronic excitations and elicits a series of cytotoxic reactions, which can be dependent on, or independent of, the generation of reactive oxygen species (Fritsch et al. 1998).
