TY - CHAP M1 - Book, Section TI - Photodynamic Therapy A1 - Newlove, Tracey A1 - Anolik, Robert T. A2 - Geronemus, Roy G. A2 - Bernstein, Leonard J. A2 - Hale, Elizabeth K. A2 - Brightman, Lori A. A2 - Karen, Julie K. A2 - Weiss, Elliot T. A2 - Anolik, Robert T. PY - 2013 T2 - Lasers and Related Technologies in Dermatology AB - Throughout the 20th century, scientists explored the use of photodynamic therapy (PDT) in medicine. PDT is a photochemical reaction in which a photosensitizing molecule, a light source, and tissue oxygen interact to produce targeted tissue destruction. Although PDT was initially thought to have great potential, its clinical use was postponed by worries of prolonged retention of the photosensitizer. By the late 20th century, 5-aminolevulinic acid (ALA) was shown to convert itself into an effective photosensitizing molecule, namely, protophorphyrin IX, in targeted tissue while also having a reasonable period of tissue retention.1 This work paved the way for dermatologic applications. Topical PDT lends itself well to cutaneous disease because of the ease of application of a photosensitizer and delivery of light. In 1999, the Food and Drug Administration (FDA) approved the use of topical ALA and blue light for the treatment of actinic keratoses (AK), and its list of on- and off-label indications has since continued to expand. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/11/09 UR - dermatology.mhmedical.com/content.aspx?aid=1175385572 ER -