A method for quantitative characterization of port wine stain (PWS) is presented. Pulsed photothermal radiometry

ABSTRACT A method for quantitative characterization of port wine stain (PWS) is presented. Pulsed photothermal radiometry(Pr'TR) uses a non-invasive infrared radiometry system to measure changes in surface temperature induced by pulsedradiation. When a pulsed laser is used to irradiate a PWS, an initial temperature jump (T-jump) is seen due to the heating of the epidermis as a result of melanin absorption. Subsequently, heat generated in the subsurface blood vessels due to hemoglobin absorption is detected by PPTR as a delayed thermal wave as the heat diffuses toward theskin surface. The time delay and magnitude of the delayed PPTR signal indicate the depth and thickness of the PWS.In this report, we present an initial clinical study of PPTR measurements on PWS patients. Computer simulationsof various classes of PWS illustrate how the PPTR signal depends on the concent.ration of epidermal melanin, and depth and thickness of the PWS. The goal of this research is to provide a means of characterizing PWS before