 Photofrin registered is a sensitizer used in photodynamic therapy, PDT, to treat cancer and skin diseases, with porphyrinoid derivatives being the most successful in producing requisite singlet oxygen. Other approved PDT sensitizers include benzoporphyrin derivative monoacid ring A, BPDMA, metatetra, hydroxylphenol, chlorine, MTHPC, enospartylchlorine E6, NPE6, and precursors to endogenous protoporphyrin-9, PPIX-1, 5, aminolevulinic acid ALA, methylaminolevulinate, MAL, hexaminolevulinate, HAL. Anthroquinone, phenothiazine, xanthine, cyanone, and curcuminoid sensitizers are also under consideration for PDT applications. This article was authored by Harold S. Freeman and Alexander B. Ormond. We are article.tv, links in the description below.