Title :
A comparative study of human skin thermal response to sapphire contact and cryogen spray cooling
Author :
Anvari, Bahman ; Milner, Thomas E. ; Tanenbaum, B. Samuel ; Nelson, J. Stuart
Author_Institution :
Dept. of Eng., Harvey Mudd Coll., Claremont, CA, USA
fDate :
7/1/1998 12:00:00 AM
Abstract :
Surface cooling, in conjunction with various thermally mediated therapeutic procedures, can provide a means to protect superficial tissues from injury while achieving destruction of deeper targeted structures. We have investigated the thermal response of in-vivo human skin to: (1) contact cooling with a sapphire window (6-12°C); and (2) spray cooling with a freon substitute cryogen [tetrafluoroethane; boiling point ≈-26°C at 1 atmospheric pressure (atm)]. Measurements utilizing infrared radiometry show surface temperature reductions from 30°C to 14-19°C are obtained within approximately is in response to sapphire contact cooling. Surface temperature reductions to values between 5°C and -9°C are obtained in response to 20-100-ms cryogen spurts. Computational results, based on fitting the measured radiometric surface temperature to estimate heat transfer parameters, show: (1) temperature reductions remain localized to approximately 200 μm of superficial tissue; and (2) values of heat flux and total energy removed per unit skin surface area at least doubled when using cryogen spray cooling.
Keywords :
biothermics; cooling; infrared imaging; patient treatment; radiometry; skin; spectral methods of temperature measurement; -9 to 5 degC; 14 to 19 degC; 6 to 12 degC; Al/sub 2/O/sub 3/; boiling point; cryogen spray cooling; cryogen spurts; deeper targeted structures; freon substitute cryogen; heat flux; heat transfer parameters; human skin thermal response; in-vivo human skin; infrared radiometry; injury; radiometric surface temperature; sapphire contact cooling; sapphire window; superficial tissues; surface cooling; surface temperature reductions; tetrafluoroethane; thermally mediated therapeutic procedures; total energy removed per unit skin surface area; Atmospheric measurements; Cooling; Heat transfer; Humans; Protection; Radiometry; Skin; Surface fitting; Temperature measurement; Thermal spraying; Aerosol Propellants; Aluminum Oxide; Body Temperature; Body Temperature Regulation; Cryotherapy; Energy Metabolism; Humans; Hydrocarbons, Fluorinated; Ice; Radiometry; Reference Values; Sensitivity and Specificity; Skin; Surface Properties;
Journal_Title :
Biomedical Engineering, IEEE Transactions on
