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Thermal responses of ex vivo human skin during multiple cryogen spurts and 1,450 nm laser pulses
Author(s) -
Zhang Rong,
RamirezSanJuan Julio C.,
Choi Bernard,
Jia Wangcun,
Aguilar Guillermo,
Kelly Kristen M.,
Nelson J. Stuart
Publication year - 2006
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.20297
Subject(s) - laser , ex vivo , optics , materials science , in vivo , thermal , human skin , biomedical engineering , medicine , physics , biology , thermodynamics , genetics , microbiology and biotechnology
Background and Objective Although cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic surgery, concern has been expressed that CSC may induce cryo‐injury. The objective of this study is to measure temperature variations at the epidermal–dermal junction in ex vivo human skin during three clinically relevant multiple cryogen spurt—laser pulse sequences (MCS‐LPS). Study Design/Materials and Methods The epidermis of ex vivo human skin was separated from the dermis and a thin‐foil thermocouple (13 µm thickness) was inserted between the two layers. Thermocouple depth and epidermal thickness were measured using optical coherence tomography (OCT). Skin specimens were preheated to 30°C before the MCS‐LPS were initiated. Three MCS‐LPS patterns, with total cryogen spray times of 38, 30, and 25 milliseconds respectively, were applied to the specimens in combination with laser fluences of 10 and 14 J/cm 2 , while the thermocouple recorded the temperature changes at the epidermal–dermal junction. Results The thermocouple effectively recorded fast temperature changes during three MCS‐LPS patterns. The lowest temperatures measured corresponded to the sequences with longer pre‐cooling cryogen spurts. No sub‐zero temperatures were measured for any of the MCS‐LPS patterns under study. Conclusions The three clinically relevant MCS‐LPS patterns evaluated in this study do not cause sub‐zero temperatures in ex vivo human skin at the epidermal–dermal junction and, therefore, are unlikely to cause significant cryogen induced epidermal injury. Lasers Surg. Med. 38:137–141, 2006. © 2006 Wiley‐Liss, Inc.