Abstract
Background and Objectives
Objective evaluation of the pigmentation index (PI) and the eythema index (EI) of human skin is a prerequisite for successful optimization of laserโ and intenseโpulsedโlight (IPL)โbased treatment modalities in dermatology.
Study Design/Materials and Methods
We describe a threeโwavelength technique for determining PI and EI as well as its particular implementation using LEDs operating at wavelengths of 560, 650, and 710 nm and a largeโarea photodiode. The instrument has been evaluated both in vitro and in vivo.
Results
In vitro, good correlation between the measured indices and results obtained with commercially available techniques has been observed. In addition, linearity of the PI with melanin concentration in the phantom medium up to 7โรโ10^โ3^ nm^โ1^ (defined as a slope of the optical density spectrum) has been established. In vivo, feasibility of using the technique for predicting the minimal erythema dose (MED), minimal phototoxic dose (MPD), and the threshold of epidermal damage in a photothermal treatment has been demonstrated.
Conclusions
The data suggest that the technique has a substantial potential as a method of preโtreatment diagnostics for photochemical and photothermal procedures. Lasers Surg. Med. 34:127โ135, 2004. ยฉ 2004 WileyโLiss, Inc.