7 September 1994 In vivo fluorescence spectroscopy and imaging of ALA-induced endogenous porphyrins in skin after Er:YAG ablation of human stratum corneum
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Proceedings Volume 2128, Laser Surgery: Advanced Characterization, Therapeutics, and Systems IV; (1994); doi: 10.1117/12.184901
Event: OE/LASE '94, 1994, Los Angeles, CA, United States
Abstract
Limited regions of human stratum corneum were removed by laser ablation using an Er:YAG laser. Immediately after this procedure, an ointment containing 5-aminolevulinic acid (ALA) was applied topically to the laser-treated and surrounding skin. The time-dependent ALA- induced biosynthesis of protoporphyrin IX was measured by fluorescence detection. Fluorescence in the red spectral region was found to occur in the ablated skin regions only. Time-resolved measurements showed the formation of long-lived fluorophores (16 ns) indicating the presence of ALA-induced monomeric porphyrin. Naturally occurring fluorophores (NAD(P)H, flavins, collagen, elastin) possess shorter fluorescence decay times. Therefore, time-gated measurements in the nanosecond region enable the specific detection of ALA-stimulated porphyrin fluorescence by choosing an appropriate time-window. In addition, detection of backscattered excitation light can be avoided. High-contrast video images of ALA-incubated fluorescent areas were obtained using this novel imaging technique.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Karsten Koenig, Herbert Schneckenburger, Wolf-Henning Boehncke, Raimund Hibst, "In vivo fluorescence spectroscopy and imaging of ALA-induced endogenous porphyrins in skin after Er:YAG ablation of human stratum corneum", Proc. SPIE 2128, Laser Surgery: Advanced Characterization, Therapeutics, and Systems IV, (7 September 1994); doi: 10.1117/12.184901; https://doi.org/10.1117/12.184901
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KEYWORDS
Luminescence

Skin

Imaging spectroscopy

Laser ablation

Er:YAG lasers

Fluorescence spectroscopy

In vivo imaging

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