1 July 2008 Risk estimation of skin damage due to ultrashort pulsed, focused near-infrared laser irradiation at 800 nm
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Abstract
New imaging techniques using near-infrared (NIR) femtosecond lasers (fs-lasers) in multiphoton laser scanning microscopy (MPLSM) have great potential for in vivo applications, particularly in human skin. However, little is known about possible risks. In order to evaluate the risk, a “biological dosimeter” was used. We irradiated fresh human skin samples with both an fs-laser and a solar simulator UV source (SSU). DNA damage introduced in the epidermis was evaluated using fluorescent antibodies against cyclobutane-pyrimidin-dimers (CPDs) in combination with immunofluorescence image analysis. Four fs-irradiation regimes (at 800-nm wavelength) were evaluated differing in laser power and step width of horizontal scans. Fs-irradiation did not give CPDs at 15-mW or 30-mW irradiation power using 10 horizontal scans every 5 microns. CPDs could be seen at 60-mW laser power and 5-µm step size and at 35-mW using 1-micron step width. Quantitative comparison of SSU-induced CPDs showed that the 60-mW laser irradiation regime is comparable to UV-irradiation, giving 0.6 minimal erythemal dose (MED). The 1-micron irradiation regime was comparable to 0.45 MED. Under these experimental conditions, the risk of DNA damage due to fs-laser irradiation on skin is in the range of natural UV-exposure.
© (2008) Society of Photo-Optical Instrumentation Engineers (SPIE)
Frank F. Fischer, Beate Volkmer, Stefan Puschmann, Ruediger Greinert, Wolfgang Breitbart, J. Kiefer, R. Wepf, "Risk estimation of skin damage due to ultrashort pulsed, focused near-infrared laser irradiation at 800 nm," Journal of Biomedical Optics 13(4), 041320 (1 July 2008). https://doi.org/10.1117/1.2960016 . Submission:
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