Light scattering study of tissues

Тучин, В. В.

doi:10.1070/pu1997v040n05abeh000236

Cited by 230 publications

(69 citation statements)

References 88 publications

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“…In that case the central limit theorem applies and the mean-square displacement of photons is proportional to time. This is typically the case for light in cloudy atmospheres [3] or in biological tissues [4].…”

Section: Introductionmentioning

confidence: 99%

Signatures of Lévy flights with annealed disorder

Baudouin

Pierrat²,

Eloy³

et al. 2014

Phys. Rev. E

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We present theoretical and experimental results of Lévy flights of light originating from a random walk of photons in a hot atomic vapor. In contrast to systems with quenched disorder, this system does not present any correlations between the position and the step length of the random walk. In an analytical model based on microscopic first principles including Doppler broadening we find anomalous Lévy-type superdiffusion corresponding to a single-step size distribution P (x) ∝ x −(1+α) , with α ≈ 1. We show that this step size distribution leads to a violation of Ohm', as expected for a Lévy walk of independent steps. Furthermore the spatial profile of the transmitted light develops power law tails [T diff (r) ∝ r −3−α ]. In an experiment using a slab geometry with hot rubidium vapor, we measured the total diffuse transmission T diff and the spatial profile of the transmitted light T diff (r). We obtained the microscopic Lévy parameter α under macroscopic multiple scattering conditions paving the way to investigation of Lévy flights in different atomic physics and astrophysics systems.

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Section: Introductionmentioning

confidence: 99%

Signatures of Lévy flights with annealed disorder

Baudouin

Pierrat²,

Eloy³

et al. 2014

Phys. Rev. E

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“…The anisotropy parameter (g) for description of the scattering process in the medium is defined as average cosine of scattering angle g = \cos h[, which ranges from g = 1, 0, and -1 for forward, isotropic, and backward scattering, respectively. The reduced scattering coefficient (l 0 s Þ (cm -1 ) is given by l 0 s = l s (1 -g) [35]. Determination of optical parameters of the tissues was carried out by curve fitting method, which is based on the inverse problem.…”

Section: Determination Of Optical Parametersmentioning

confidence: 99%

Multilayer imaging and compositional analysis of human male breast by laser reflectometry and Monte Carlo simulation

Pandian

Lad

Singh

2009

Med Biol Eng Comput

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The laser backscattering from biological tissues depends on their composition and blood flow. The onset of abnormalities in tissues is associated with the change in composition at a specific location which may affect laser backscattering. The objective of this work is to study the point-to-point compositional variation of male breast tissues as this site has been prone to cancer development. The normalized backscattered intensity (NBI) profiles at various locations of human chest region of five subjects by multi-probe laser reflectometer are obtained. Based on these data the images of tissue composition, showing the point-to-point changes at various depths from the tissue surface, are reconstructed. The analysis of data shows that the maximum NBI variation is at the pectoralis major muscle and minimum variation is observed at the sternum. The optical parameters, based on the NBI data obtained for five human subjects, show the maximum increase in absorption (p < 0.0001) and minimum change in scattering (p < 0.0001) coefficients compared to that as observed at the sternum. Also the minimum absorption and maximum scattering coefficients are observed at the pectoralis major muscles. The regional variations of NBI and optical parameters further support these findings. The variations in the NBI and optical parameters may indicate the compositional change in tissues, which could be used for diagnostic and therapeutic applications of laser.

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“…For collection of backscattered photons, the separation between surface and tips of optical fibers through acceptance angle was accounted. Further details of the procedure are given elsewhere [18,19].…”

Section: Determination Of Optical Parameters By Monte Carlo Simulationmentioning

confidence: 99%