A One Layer Tissue Fluorescence Model Based On Electromagnetic Theory

Panou-Diamandi, O.; Uzunoglu, N.K.; Zacharakis, Giannis; Filippidis, George; Papazoglou, Theodore G.; Koutsouris, Dimitrios

doi:10.1163/156939398x01321

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…16 -23 At the same time, autofluorescence properties of human skin in vivo were systematically studied and characterized. 24 -26 The results demonstrated that the spatial distribution of the skin fluorophores is not uniform, as was assumed in theoretical models, [10][11][12][13][14][15]24 and has a layered quasiperiodical structure. 19,26 In this paper, we investigate the distribution of fluorescence emission within skin tissue and the detector depth sen-sitivity, provided that the distribution of skin fluorophores corresponds to the collagen fiber packing.…”

Section: Introductionmentioning

confidence: 85%

“…Fluorescence emission is affected by several factors including spatial distribution of the fluorophore and its photophysical parameters ͑i.e., quantum yield, fluorescence lifetime, etc.͒ 9 Both excitation and fluorescence radiation that traverse and arise from a volume of tissue are subjected to tissue optics ͑scattering, absorption, and anisotropy͒. To elucidate these effects various theoretical models have been developed: electromagnetic theory, 10 Kubelka-Munk approximation, 11 diffusion theory, [12][13][14] random walk theory, 15 and Monte Carlo ͑MC͒ techniques. 16 -23 At the same time, autofluorescence properties of human skin in vivo were systematically studied and characterized.…”

Section: Introductionmentioning

confidence: 99%

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Amending of fluorescence sensor signal localization in human skin by matching of the refractive index

2004

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Fluorescence diagnostic techniques are notable amongst many other optical methods because they offer high sensitivity and noninvasive measurement of tissue properties. However, a combination of multiple scattering and physical heterogeneity of biological tissues hampers interpretation of the fluorescence measurements. Analyses of the spatial distribution of endogenous and exogenous fluorophores excitation within tissues and their contribution to the detected signal localization are essential for many applications. We have developed a novel Monte Carlo technique that gives a graphical perception of how the excitation and fluorescence detected signal are localized in tissues. Our model takes into account the spatial distribution of fluorophores, the variation of concentrations and quantum yield. We demonstrate that matching the refractive indices of the ambient medium and topical skin layer improves spatial localization of the detected fluorescence signal within the tissues.

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Section: Introductionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Amending of fluorescence sensor signal localization in human skin by matching of the refractive index

2004

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“…In most media, the measured emission spectrum is distorted due to light reabsorption and/or scattering, which makes its interpretation especially difficult. Different theories have emerged that attempt to explain the propagation of light in a turbid medium, including fluorescence emission: radiative transfer equation (Richards-Kortum et al, 1989;Gardner et al, 1996;Emmel & Hersch, 1998), two-flux Kubelka-Munk (KM) theory and four-flux extensions (Allen, 1964;Fukshansky & Kazarinova, 1980;Bonham, 1986;Shakespeare & Shakespeare, 2003), Monte Carlo simulations (Wu et al, 1993;Crilly et al, 1997;Welch et al, 1997), or rigorous analysis of tissue fluorescence based on electromagnetic theory (Panou-Diamandi et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

FluorMODleaf: A new leaf fluorescence emission model based on the PROSPECT model

Pedrós

Goulas

Jacquemoud

et al. 2010

Remote Sensing of Environment

103

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A new model of chlorophyll a fluorescence emission by plant leaves, FluorMODleaf, is presented. It is an extension of PROSPECT, a widely used leaf optical properties model that regards the leaf as a pile of N absorbing and diffusing elementary plates. In FluorMODleaf, fluorescence emission of an infinitesimal layer of thickness dx is integrated over the entire elementary plate. The fluorescence source function is based on the excitation spectrum of diluted isolated thylakoids and on the emission spectra of isolated photosystems, PSI and PSII, which are the main pigment-protein complexes involved in the initial stages of photosynthesis. Scattering within the leaf is produced by multiple reflections within and between elementary plates. The input variables of FluorMODleaf are: the number of elementary plates N, also called leaf structure parameter, the total chlorophyll content C ab , the total carotenoid content C cx , the equivalent water thickness C w , and the dry matter content C m (or leaf mass per area), as in the new PROSPECT-5, plus the σ II /σ I ratio referring to the relative absorption cross section of PSI and PSII, and the fluorescence quantum efficiency of PSI and PSII, τ I and τ II , that are introduced here as mean fluorescence lifetimes. The model, which considers the reabsorption of emitted light within the leaf, allows good quantitative estimation of both upward and downward apparent spectral fluorescence yield (ASFY) at different excitation wavelengths from 400 nm to 700 nm. It also emphasizes the role of scattering in fluorescence emission by leaves having high chlorophyll content.

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“…To predict the fluorescence distribution in biological media, various techniques have been developed and used. These include electromagnetic theory [9], Kubelka-Munk approximation [10], the diffusion theory [11,12], random walk theory [13][14][15] and Monte Carlo (MC) techniques [16][17][18][19][20][21][22][23]. The MC technique has a number of advantages over analytical models: different boundary conditions can be accounted for; the technique allows the investigation of various phenomena; the method is suitable for both highly scattering and absorbing multilayered media; the technique may also be adapted for fluorescence modelling.…”

Section: Introductionmentioning

confidence: 99%

Analysis of skin tissues spatial fluorescence distribution by the Monte Carlo simulation

Churmakov

Meglinski

Piletsky

et al. 2003

J. Phys. D: Appl. Phys.

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A novel Monte Carlo technique of simulation of spatial fluorescence distribution within the human skin is presented. The computational model of skin takes into account the spatial distribution of fluorophores, which would arise due to the structure of collagen fibres, compared to the epidermis and stratum corneum where the distribution of fluorophores is assumed to be homogeneous. The results of simulation suggest that distribution of auto-fluorescence is significantly suppressed in the near-infrared spectral region, whereas the spatial distribution of fluorescence sources within a sensor layer embedded in the epidermis is localized at an 'effective' depth.

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A One Layer Tissue Fluorescence Model Based On Electromagnetic Theory

Cited by 7 publications

References 15 publications

Amending of fluorescence sensor signal localization in human skin by matching of the refractive index

Amending of fluorescence sensor signal localization in human skin by matching of the refractive index

FluorMODleaf: A new leaf fluorescence emission model based on the PROSPECT model

Analysis of skin tissues spatial fluorescence distribution by the Monte Carlo simulation

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