ED 50 study of femtosecond terawatt laser pulses on porcine skin

Kumru, Semih S.; Cain, Clarence P.; Noojin, Gary D.; Imholte, Michelle L.; Cox, Duane; Crane, Carrie C.; Rockwell, Benjamin A.

doi:10.1117/12.585036

Cited by 2 publications

(1 citation statement)

References 6 publications

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“…Only one MVL-ED 50 threshold has been reported for terawatts. 4 We have reported the skin MVL thresholds using the nanosecond and microsecond pulse durations previously and compared them with the ANSI standards. This paper will be the first combined reporting of so many pulse durations, wavelengths and spot sizes for the skin using Yucatan mini-pigs as the subjects.…”

Section: Introductionmentioning

confidence: 99%

Infrared laser damage thresholds for skin at wavelengths from 0.810 to 1.54 microns for femto-to-microsecond pulse durations

Cain

Roach²,

Stolarski

et al. 2007

SPIE Proceedings

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In this paper we report on our combined measurements of the visible lesion thresholds for porcine skin for wavelengths in the infrared from 810 nm at 44 fs to 1318 nm at pulse durations of 50 ns and 350 µs to 1540 nm including pulse durations of 31 ns and 600 µs. We also measure thresholds for various spot sizes from less than 1 mm to 5 mm in diameter. All three wavelengths and five pulse durations are used extensively in research and the military. We compare these minimum visible lesion thresholds with ANSI standards set for maximum permissible exposures in the infrared wavelengths. We have measured non-linear effects at the laser-tissue interface for pulse durations below 1 µs and determined that damage at these short pulse durations are usually not thermal effects. Damage at the skin surface may include acoustical effects, laser ablation and/or low-density plasma effects, depending on the wavelength and pulse duration. Also the damage effects may be short-lived and disappear within a few days or may last for much longer time periods including permanent discolorations. For femtosecond pulses at 810 nm, damage was almost instant and at 1 hour had an ED 50 of 8.2 mJ of pulse energy. After 24 hours, most of the lesions disappeared and the ED 50 increased by almost a factor of 3 to 21.3 mJ. There was a similar trend for the 1.318 µ laser for spot sizes of 2 mm and 5 mm where the ED 50 was larger after 24 hours. However, for the 1.54 µ laser with a spot size of 5 mm, the ED 50 actually decreased by a small amount; from 6.3 Jcm -2 to 6.1 Jcm -2 after 24 hours. Thresholds also decreased for the 1314 nm laser at 350 µs for spot sizes of 0.7 mm and 1.3 mm diameter after 24 hours. Different results were obtained for the 1540 nm laser at 600 µs pulse durations where the ED 50 decreased for spot sizes 1 mm and below, but increased slightly for the 5 mm diameter spot size from 6.4 Jcm -2 to 7.4 Jcm -2

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Section: Introductionmentioning

confidence: 99%

Infrared laser damage thresholds for skin at wavelengths from 0.810 to 1.54 microns for femto-to-microsecond pulse durations

Cain

Roach²,

Stolarski

et al. 2007

SPIE Proceedings

Self Cite

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Laser-induced injury of the skin: validation of a computer model to predict thresholds

Jean

Schulmeister

2021

Biomed. Opt. Express

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The exposure and emission limits of ICNIRP, IEC 60825-1 and ANSI Z136.1 to protect the skin are based on a limited number of in-vivo studies. To broaden the database, a computer model was developed to predict injury thresholds in the wavelength range from 400 nm to 20 µm and was validated by comparison with all applicable experimental threshold data (ED50) in the wavelength range from 488 nm to 10.6 µm and exposure durations between 8 µs and 630 s. The model predictions compare favorably with the in-vivo data with an average ratio of computer prediction to ED50 of 1.01 (standard deviation ± 46%) and a maximum deviation of 2.6. This computer model can be used to improve exposure limits or for a quantitative risk analysis of a given exposure of the skin.

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ED 50 study of femtosecond terawatt laser pulses on porcine skin

Cited by 2 publications

References 6 publications

Infrared laser damage thresholds for skin at wavelengths from 0.810 to 1.54 microns for femto-to-microsecond pulse durations

Infrared laser damage thresholds for skin at wavelengths from 0.810 to 1.54 microns for femto-to-microsecond pulse durations

Laser-induced injury of the skin: validation of a computer model to predict thresholds

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