&lt;title&gt;Photobleaching of endogenous fluorochroms in tissues in vivo during laser irradiation&lt;/title&gt;

Stratonnikov, Alexander A.; Polikarpov, Vladimir S.; Loschenov, Victor B.

doi:10.1117/12.431555

Cited by 15 publications

(8 citation statements)

References 25 publications

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“…Laser-excited tissue AF spectra have been studied extensively over recent decades [1][2][3][4] . AF intensity decrease during irradiation (photo-bleaching) was observed by several authors [5][6][7][8] . In most cases it was characterized as exponential fading with time, indicating to decreased absorption or optical washout of fluorophores at the superficial layer of skin during irradiation.…”

Section: Introductionmentioning

confidence: 85%

RGB imaging of laser-excited skin autofluorescence bleaching rates

Jakovels

Spīgulis

2010

SPIE Proceedings

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Section: Introductionmentioning

confidence: 85%

RGB imaging of laser-excited skin autofluorescence bleaching rates

Jakovels

Spīgulis

2010

SPIE Proceedings

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“…Fluorescence photobleaching of exogenous fluorophores is widely used to determine the efficiency of photosensitizers, such as protoporphyrin IX, in photodynamic therapy. [1][2][3][4] The photobleaching of endogenous fluorophores of the skin can be utilized for different applications. In Raman spectroscopy, a fluorescent component is usually unwanted because a large background component complicates the analysis of Raman bands and can introduce artifacts during data analysis.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast to this interpretation, Berglund 18 claimed that the decay is truly nonexponential and that an exponential decay can solely be described by the spatially varying power density within the laser profile. Since higher intensity entails faster fluorescence decay, 4 the varying power density can introduce exponential decay rates. The simulations for this study were based on surface-immobilized fluorescent single molecules.…”

Section: Introductionmentioning

confidence: 99%

“…A recovery of the autofluorescence from the skin in the range of 3 to 6 days after irradiation has been observed in several studies, which suggest photochemical effects of the endogenous fluorophores. These studies were performed in vivo 4,17 or were assumed to be performed in vivo. 3 Photobleaching has also been suggested to be due to the permanent photodecomposition of fluorophores.…”

Section: Introductionmentioning

confidence: 99%

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Depth-dependent autofluorescence photobleaching using 325, 473, 633, and 785 nm of porcine ear skin ex vivo

2017

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Autofluorescence photobleaching describes the decrease of fluorescence intensity of endogenous fluorophores in biological tissue upon light irradiation. The origin of autofluorescence photobleaching is not fully understood. In the skin, the spatial distribution of various endogenous fluorophores varies within the skin layers. Most endogenous fluorophores are excited in the ultraviolet and short visible wavelength range, and only a few, such as porphyrins (red) and melanin (near-infrared), are excited at longer wavelengths. The excitation wavelength- and depth-dependent irradiation of skin will therefore excite different fluorophores, which will likely influence the photobleaching characteristics. The autofluorescence photobleaching of porcine ear skin has been measured ex vivo using 325, 473, 633, and 785 nm excitation at different skin depths from the surface to the dermis at 150 ? ? m . Confocal Raman microscopes were used to achieve sufficient spatial resolution of the measurements. The autofluorescence area under the curve was measured for 21 consecutive acquisitions of 15 s. In all cases, the photobleaching follows a two-exponential decay function approximated by nonlinear regression. The results show that photobleaching can be applied to improve the signal-to-noise ratio in Raman spectroscopy for all of the applied excitation wavelengths and skin depths.

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“…a b Figure 8. Skin autofluorescence photobleaching at continuous 532nm laser irradiation (10-85 mW/cm 2 ): a -temporal changes of the emission spectrum [36], b -partial recovery of the autofluorescence intensity after interrupted excitation [37].…”

Section: Prototype Device For Skin Fluorescence Imaging With a Smartpmentioning

confidence: 99%

Multispectral, Fluorescent and Photoplethysmographic Imaging for Remote Skin Assessment

Spīgulis¹

2017

Preprint

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Optical tissue imaging has several advantages over the routine clinical imaging methods, including non-invasiveness (does not change the structure of tissues), remote operation (avoids infection) and ability to quantify the tissue condition by means of specific image parameters. Dermatologists and other skin experts need compact (preferably pocket-size), self-sustained and easy-to-use imaging devices. The operational principles and designs of ten portable in-vivo skin imaging prototypes developed at the Biophotonics Laboratory of Institute of Atomic Physics and Spectroscopy, University of Latvia during the recent five years are presented in this paper. Four groups of imaging devices are considered. Multi-spectral imagers offer possibilities for distant mapping of specific skin parameters, so facilitating better diagnostics of skin malformations. Autofluorescence intensity and photobleaching rate imagers show a promising potential for skin tumor identification and margin delineation. Photoplethysmography video-imagers ensure remote detection of cutaneous blood pulsations and can provide real-time information on cardiovascular parameters and anesthesia efficiency. Multimodal skin imagers perform several of the above-mentioned functions by taking a number of spectral and video images with the same image sensor. Design details of the developed prototypes and results of clinical tests illustrating their functionality are presented and discussed.

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<title>Photobleaching of endogenous fluorochroms in tissues in vivo during laser irradiation</title>

Cited by 15 publications

References 25 publications

RGB imaging of laser-excited skin autofluorescence bleaching rates

RGB imaging of laser-excited skin autofluorescence bleaching rates

Depth-dependent autofluorescence photobleaching using 325, 473, 633, and 785 nm of porcine ear skin ex vivo

Multispectral, Fluorescent and Photoplethysmographic Imaging for Remote Skin Assessment

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