21 May 2001 Sequential cryogen spraying for heat flux control at the skin surface
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Proceedings Volume 4244, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems XI; (2001) https://doi.org/10.1117/12.427777
Event: BiOS 2001 The International Symposium on Biomedical Optics, 2001, San Jose, CA, United States
Abstract
Heat transfer rate at the skin-air interface is of critical importance for the benefits of cryogen spray cooling in combination with laser therapy of shallow subsurface skin lesions, such as port-wine stain birthmarks. With some cryogen spray devices, a layer of liquid cryogen builds up on the skin surface during the spurt, which may impair heat transfer across the skin surface due to relatively low thermal conductivity and potentially higher temperature of the liquid cryogen layer as compared to the spray droplets. While the mass flux of cryogen delivery can be adjusted by varying the atomizing nozzle geometry, this may strongly affect other spray properties, such as lateral spread (cone), droplet size, velocity, and temperature distribution. We present here first experiments with sequential cryogen spraying, which may enable accurate mass flux control through variation of spray duty cycle, while minimally affecting other spray characteristics. The observed increase of cooling rate and efficiency at moderate duty cycle levels supports the above described hypothesis of isolating liquid layer, and demonstrates a novel approach to optimization of cryogen spray devices for individual laser dermatological applications.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Boris Majaron, Boris Majaron, Guillermo Aguilar, Guillermo Aguilar, Brooke Basinger, Brooke Basinger, Lise Lyngsnes Randeberg, Lise Lyngsnes Randeberg, Lars Othar Svaasand, Lars Othar Svaasand, Enrique J. Lavernia, Enrique J. Lavernia, J. Stuart Nelson, J. Stuart Nelson, } "Sequential cryogen spraying for heat flux control at the skin surface", Proc. SPIE 4244, Lasers in Surgery: Advanced Characterization, Therapeutics, and Systems XI, (21 May 2001); doi: 10.1117/12.427777; https://doi.org/10.1117/12.427777
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