Open AccessHand‐held pulsed photothermal radiometry system to estimate epidermal temperature rise during laser therapy
Author(s) -
Jung Byungjo,
Kim ChangSeok,
Choi Bernard,
Stuart Nelson J.
Publication year - 2006
Publication title -
skin research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.521
H-Index - 69
eISSN - 1600-0846
pISSN - 0909-752X
DOI - 10.1111/j.0909-752x.2006.00175.x
Subject(s) - optics , photothermal therapy , laser , biomedical engineering , materials science , calibration , signal (programming language) , human skin , nuclear medicine , optoelectronics , medicine , physics , computer science , quantum mechanics , biology , genetics , programming language
Background/purpose: During laser therapy of port wine stain (PWS) birthmarks in human skin, measurement of the epidermal temperature rise (Δ T epi ) is important to determine the maximal permissible light dose. In order to measure Δ T epi on a specific PWS skin site, we developed an AC‐coupled hand‐held pulsed photothermal radiometry (PPTR) system, which overcomes the in vivo measurement limitations of bench‐top systems. Methods: The developed hand‐held PPTR system consists of an infrared (IR) lens, AC‐coupled thermoelectrically cooled IR detector, laser hand‐piece holder, and positioning aperture. The raw AC‐coupled signal was integrated to obtain a higher signal‐to‐noise ratio (SNR). The experimental temperature difference (Δ T ) calibration was compared with theoretical computations. In vitro and in vivo measurements of Δ T were performed with a tissue phantom as a function of radiant exposure and human subject as a function of melanin concentration, respectively. Results: The integrated AC‐coupled signal provided higher SNR as compared with the raw AC‐coupled signal. The experimental Δ T calibration resulted in good agreements with the theoretical results. The in vitro and in vivo results also presented good agreements with theory. Conclusions: A fiber‐free, hand‐held AC‐coupled PPTR system is capable of accurate epidermis temperature rise (Δ T epi ) measurements of human skin during pulsed laser exposure.