ABSTRACT
The development of Photofrin-based clinical photodynamic therapy (PDT) has progressed at an accelerated pace in recent years and, correspondingly, our understanding of the mechanisms leading to PDT tissue destruction has expanded. In a typical PDT treatment in experimental rodent tumors, there is rapid and severe vascular stasis, which inevitably causes tissue hypoxia and anoxia. The chapter outlines some of the factors that determine the extent and time frame of the PDT tissue response, including information derived from a variety of different new sensitizers for which preclinical data exist. Most sensitizers are distributed to, and are retained by, normal as well as neoplastic tissues. Knowledge of localization of photosensitizers in skin is important because the response of this tissue defines the limiting photodynamic dose in dermato-logical PDT cases. Knowledge of localization of photosensitizers in skin is important because the response of this tissue defines the limiting photodynamic dose in dermato-logical PDT cases.
