&lt;title&gt;Cryogen spray cooling of human skin: effects of ambient humidity level, spraying distance, and cryogen boiling point&lt;/title&gt;

Anvari, Bahman; Steeg, Benjamin J. Ver; Milner, Thomas E.; Tanenbaum, B. Samuel; Gerstner, Eliot; Kimel, S.; Nelson, J. Stuart

doi:10.1117/12.297833

Cited by 18 publications

(14 citation statements)

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“…The only FDA-approved cryogen compound currently used in dermatology is tetra¯uoroethane (C 2 H 2 F 4 , also known as R-134a), with T b À 26 C at atmospheric pressure. From earlier studies, it is well known that the spray temperature (T) varies between À 25 C to À 60 C, depending primarily on the distance from the nozzle to the skin surface [9,10,11] and the atomizer nozzle design [10,12,13].…”

Section: Introductionmentioning

confidence: 99%

Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Aguilar

Majaron

Pope³

et al. 2001

Lasers Surg Med

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Section: Introductionmentioning

confidence: 99%

Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Aguilar

Majaron

Pope³

et al. 2001

Lasers Surg Med

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“…The thermocouple was supported by a rigid stick and inserted into the center of the spray cone at varying distances from the nozzle. Since water condensation and freezing can affect temperature measurements, these experiments were conducted in a chamber filled with dry air (relative humidity below 5%) [17].…”

Section: Temperature Measurementsmentioning

confidence: 99%

Experimental study of cryogen spray properties for application in dermatologic laser surgery

Aguilar

Majaron

Karapetian

et al. 2003

IEEE Trans. Biomed. Eng.

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Abstract-Cryogenic sprays are used for cooling human skin during laser dermatologic surgery. In this paper, six straight-tube nozzles are characterized by photographs of cryogenic spray shapes, as well as measurements of average droplet diameter, velocity, and temperature. A single-droplet evaporation model to predict average spray droplet diameter and temperature is tested using the experimental data presented here. The results show two distinct spray patterns-sprays for 1.4-mm-diameter nozzles (wide nozzles) show significantly larger average droplet diameters and higher temperatures as a function of distance from the nozzle compared with those for 0.5-0.8-mm-diameter nozzles (narrow nozzles). These results complement and support previously reported studies, indicating that wide nozzles induce more efficient heat extraction than the narrow nozzles.

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“…These sprays are produced by atomizing nozzles as cryogen is released from a pressurized container at 6.7 bar (its saturation pressure at room temperature) to the atmosphere. Based on systematic experiments, we have determined that the average spray temperature reaches a minimum between À55 and À628C, regardless of nozzle position [11], geometry [10,17], and relative humidity [10,18] and, therefore, we choose a value À608C to represent a constant T c for this study.…”

Section: Definition Of Cooling Efficiencymentioning

confidence: 99%

“…To solve this problem, recent studies have sought to optimize cryogen spurt durations to maximize the temperature difference between the epidermis and PWS vessels [6,7]. Other studies have focused on increasing the rate of the heat extraction through the skin surface (q) by different means, such as variation of nozzle diameter [8,9], nozzle-to-skin distance [10,11], control of cryogen deposition [12], and enhancement of cryogen film evaporation [13]. In general, it has been concluded that cryogen spurts of 100-250 milliseconds result in better epidermal protection than that provided by 30-50 milliseconds spurts-which most physicians still use, while the increase in q by all these means appears to be moderate.…”

Section: Introductionmentioning

confidence: 99%

Cryogen spray cooling efficiency: Improvement of port wine stain laser therapy through multiple‐intermittent cryogen spurts and laser pulses

et al. 2002

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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 mm thickness) was inserted between the two layers. Thermocouple depth and epider-mal thickness were measured using optical coherence tomography (OCT). Skin specimens were preheated to 308C 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.

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<title>Cryogen spray cooling of human skin: effects of ambient humidity level, spraying distance, and cryogen boiling point</title>

Cited by 18 publications

References 0 publications

Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Influence of nozzle‐to‐skin distance in cryogen spray cooling for dermatologic laser surgery

Experimental study of cryogen spray properties for application in dermatologic laser surgery

Cryogen spray cooling efficiency: Improvement of port wine stain laser therapy through multiple‐intermittent cryogen spurts and laser pulses

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