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Skin model surface temperatures during single and multiple cryogen spurts used in laser dermatologic surgery
Julio C Ramirez-San-Juan1, Guillermo Aguilar, Alia T Tuqan
1Beckman Laser Institute and Medical Clinic, University of California, Irvine, California 92612, USA.
Lasers in Surgery and Medicine
|February 11, 2005
Summary
Cryogen spray cooling (CSC) applied to human skin phantoms (HSP) shows that cooling patterns significantly impact epidermal protection. Multiple cryogen spurts (MCS) may offer better cryo-injury prevention than single cryogen spurts (SCS) for longer cooling durations.
Area of Science:
- Dermatology
- Biomedical Engineering
- Thermal Physics
Background:
- Cryogen spray cooling (CSC) is utilized in laser dermatologic surgery to mitigate epidermal damage.
- Concerns exist regarding potential cryo-injury induced by CSC, necessitating further investigation.
Purpose of the Study:
- To evaluate the effects of prolonged cryogen spray cooling (CSC) on human skin phantoms (HSP).
- To measure key thermal parameters including minimum surface temperature (T(min)), time to T(min) (t(Tmin)), sub-zero time (Δt(s)), and residence time (Δt(r)) under various CSC conditions.
Main Methods:
- Human skin phantoms (HSP) were subjected to 17 different cryogen spray patterns, encompassing single (SCS) and multiple (MCS) spurts.
- Total cryo-delivery time (Δt(c)) and total cooling time (Δt(total)) were systematically varied.
- Initial HSP substrate temperatures (T(i)) of 23°C and 70°C were investigated.
Main Results:
- For total cooling times (Δt(total)) up to 110 milliseconds, both SCS and MCS exhibited negligible differences in thermal parameters.
- Beyond 110 milliseconds, while T(min) and t(Tmin) remained similar, MCS demonstrated more pronounced differences in sub-zero time (Δt(s)) and residence time (Δt(r)) compared to SCS.
- In prolonged cooling (110 ms < Δt(total) ≤ 280 ms), MCS maintained T(min) and Δt(s) similar to values observed at Δt(total) = 110 ms.
Conclusions:
- SCS and MCS provide comparable epidermal protection for total cooling times up to 110 milliseconds.
- For extended cooling durations (110 ms < Δt(total) ≤ 280 ms), MCS may offer advantages in preventing cryo-injury by maintaining shorter sub-zero durations.