Porcine skin damage thresholds for 0.6 to 9.5 cm beam diameters from 1070-nm continuous-wave infrared laser radiation

Rebecca L Vincelette,Jeffrey W Oliver,David J Stolarski,Kurt J Schuster,Semih S Kumru,Gary D Noojin,Aurora D Shingledecker,Corey A Harbert

doi:10.1117/1.jbo.19.3.035007

Rebecca L Vincelette, Jeffrey W Oliver + Show 6 more

Open Access

https://doi.org/10.1117/1.jbo.19.3.035007

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Abstract

There is an increasing use of high-power fiber lasers in manufacturing and telecommunications industries operating in the infrared spectrum between 1000 and 2000 nm, which are advertised to provide as much as 10 kW continuous output power at 1070 nm. Safety standards have traditionally been based on experimental and modeling investigations with scant data available for these wavelengths. A series of studies using 1070-nm infrared lasers to determine the minimum visible lesion damage thresholds in skin using the Yucatan miniature pig (Sus scrofa domestica) for a range of beam diameters (0.6, 1.1, 1.9, 2.4, 4.7, and 9.5 cm) and a range of exposure durations (10 ms to 10 s) is presented. Experimental peak temperatures associated with each damage threshold were measured using thermal imaging. Peak temperatures at damage threshold for the 10-s exposures were ∼10°C lower than those at shorter exposures. The lowest and highest experimental minimum visible lesion damage thresholds were found to have peak radiant exposures of 19 and 432 J/cm2 for the beam diameter-exposure duration pairs of 2.4 cm, 25 ms and 0.6 cm, 10 s, respectively. Thresholds for beam diameters >2.5 cm had a weak to no effect on threshold radiant exposure levels for exposure times ≤0.25 s, but may have a larger effect on thresholds for exposures ≥10 s.

Highlights

The number of lasers in the operational range of 1000 to 2000 nm continues to increase in medical, industrial, communications, and military applications, while relatively few safety studies for skin damage from continuous-wave (CW) exposures at these wavelengths can be found in the literature
The maximum permissible exposure (MPE) recommended through the ANSI Z136.1-20071 is for a limiting, or measurement, aperture diameter of 0.35 cm in this wavelength region for exposures to skin with little empirical evidence that the standard recommendations are adequate for larger beam diameters, especially for highly penetrating wavelengths such as 1070 nm
A total of 1306 skin exposures were completed on both flanks of 22 Yucatan miniature pigs with the 1070-nm laser

Summary

Introduction

The number of lasers in the operational range of 1000 to 2000 nm continues to increase in medical, industrial, communications, and military applications, while relatively few safety studies for skin damage from continuous-wave (CW) exposures at these wavelengths can be found in the literature. High-power fiber lasers utilize advanced technologies to combine active optical fibers with semiconductor diodes. These active fibers allow for an extremely high-intensity light out of a very small core, making it possible to produce multikilowatt lasers. For these lasers, powers >10 kW are routinely used in manufacturing processes and the telecommunications industry. The maximum permissible exposure (MPE) recommended through the ANSI Z136.1-20071 is for a limiting, or measurement, aperture diameter of 0.35 cm in this wavelength region for exposures to skin with little empirical evidence that the standard recommendations are adequate for larger beam diameters, especially for highly penetrating wavelengths such as 1070 nm. Irradiances can exceed 10 kW∕cm[2] and little or no minimum damage threshold data are available for these high levels

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