Cooling efficiency of cryogen spray during laser therapy of skin
| Autor: | Guillermo Aguilar, Lars O. Svaasand, Lise Lyngsnes Randeberg, Sol Kimel, Enrique J. Lavernia, J.S. Nelson, Boris Majaron |
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| Rok vydání: | 2003 |
| Předmět: |
Pathology
medicine.medical_specialty Silver Materials science Nozzle Human skin Dermatology Heat transfer coefficient law.invention Thermal conductivity law Thermal insulation Hydrocarbons Chlorinated Stratum corneum medicine Humans Low-Level Light Therapy Ethane business.industry Port-wine stain Thermal Conductivity Equipment Design medicine.disease Laser medicine.anatomical_structure Cryotherapy Thermography Surgery Skin Temperature business Biomedical engineering |
| Zdroj: | Lasers in Surgery and Medicine. 32:137-142 |
| ISSN: | 1096-9101 0196-8092 |
| Popis: | Background and Objectives: Cryogen spray cooling (CSC) is used extensively for epidermal protection during laser-induced photothermolysis of port wine stains and other vascular skin lesions. The efficacy of CSC depends critically on the heat transfer coefficient (H) at the skin surface for which, however, no reliable values exist. Reported values for H, based on tissue phantoms, vary from 1,600 to 60,000 W/m 2 K. Study Design/Materials and Methods: A simple experimental model was designed and constructed, consisting of a pure silver-measuring disk (diameter 10 mm, thickness � 1 mm), embedded in a thermal insulator. The disk was covered with a 10 mm thick stratum corneum layer, detached from in vivo human skin. The heat transfer coefficient of the stratum corneum/cryogen interface was measured during CSC with short spurts of atomized tetrafluoroethane. Results:H was found to be dependent on the specific design of the cryogen valve and nozzle. With nozzles used in typical clinical settings,H was 11,500 W/m 2 K, when averaged over a 100 ms spurt, and 8,000 W/m 2 K when averaged over a 200 ms spurt. Conclusions: The presented model enables accurate prediction of H and thus improve control over temperature depth profile and cooling efficiency during laser therapy. Thereby, it may contribute to improvement of therapeutic outcome. Lasers Surg. Med. 32:137–142, 2003. 2003 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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