Coupled Poroviscoelastic and Optical Monte Carlo Simulation of Dynamic Light Transport Through Indented Soft Tissue

2013 ◽  
Author(s):  
William C. Vogt ◽  
Christopher G. Rylander
Keyword(s):  
Refractive Index ◽  
Water Distribution ◽  
Biological Tissues ◽  
Light Transport ◽  
Mathematical Framework ◽  
Interstitial Fluid Flow ◽  
Tissue Water ◽  
Porous Flow ◽  
Optical Clearing ◽  
Tissue Optical Properties

Biological tissues are heterogeneous materials that may be considered mixtures of water, proteins, and cells. The large mismatch in refractive index between these constituents causes tissues to be highly turbid, diffusing light and limiting the efficacy of optical diagnostic and therapeutic techniques [1]. Mechanical optical clearing is a technique for reducing tissue scattering and absorption using controlled tissue deformation. Mechanical optical clearing is performed using indentation to locally modify tissue optical properties, including refractive index [2] and reduced scattering coefficient [3]. This effect is attributed to transient changes in tissue water distribution as a result of interstitial fluid flow due to tissue compression. In this study, we have developed a multi-domain mathematical framework for simulating mechanical optical clearing effects on tissue mechanical and optical behavior, including hyperelasticity, viscoelasticity, porous flow, and light transport. This model was then fitted to mechanical force data and used to predict experimentally measured optical transmission.

Enhancement of OCT imaging by blood optical clearing in vessels – A feasibility study

2016 ◽  
Vol 5 (2) ◽  
Author(s):  
Olga Zhernovaya ◽  
Valery V. Tuchin ◽  
Martin J. Leahy
Keyword(s):  
Light Scattering ◽  
Blood Vessels ◽  
Feasibility Study ◽  
Biological Tissues ◽  
Intradermal Injection ◽  
Light Transport ◽  
Optical Clearing ◽  
Intravenous Injections ◽  
Oct Imaging ◽  
System Operating

AbstractThe results of a feasibility study of the application of PEG-300 and fructose as two independent optical clearing agents for the reduction of light scattering in biological tissues are presented.An OCT system operating at 1300 nm was used to study optical clearing effects. InThe intradermal injection of fructose in combination with the intravenous injection of PEG-300 led to a rapid optical clearing effect. In the experiments on miceThe experiments on mice have clearly demonstrated that intradermal and intravenous injections of optical clearing agents enhanced light transport through the skin and blood vessels.

QUANTITATIVE CONTROL OF OPTICAL CLEARING EFFECTS STUDIED WITH TISSUE-LIKE PHANTOM

2010 ◽  
Vol 03 (03) ◽  
pp. 195-202 ◽  
Author(s):  
JINGYING JIANG ◽  
WEI CHEN ◽  
QILIANG GONG ◽  
KEXIN XU
Keyword(s):  
Optical Properties ◽  
Biological Tissues ◽  
Porcine Skin ◽  
Tissue Samples ◽  
Optical Clearing ◽  
Tissue Optical Properties ◽  
Application Potential ◽  
The Difference ◽  
Tissue Optical Clearing

Tissue optical clearing by use of optical clearing agents (OCAs) has been proven to have potential to reduce the highly scattering effect of biological tissues in optical techniques. However, the difference in tissue samples could lead to unreliable results, making it difficult to quantitatively control the dose of OCAs during the course of tissue optical clearing. In this work, in order to study the effects of optical clearing, we customized tissue-like phantoms with optical properties of some biological tissue. Diffuse reflectance and total transmittance of tissue-like phantoms with different OCAs (DMSO or glycerol) and porcine skin tissues were measured. Then optical property parameters were calculated by inverse adding-doubling (IAD) algorithm. Results showed that OCAs could lead to a reduction in scattering of tissue-like phantoms as it did to porcine skin tissue in vitro. Furthermore, a series of relational expressions could be fit to quantitatively describe the relationship between the doses of OCAs and the reduction of scattering effects. Therefore, proper tissue-like phantom could facilitate optical clearing to be used in quantitative control of tissue optical properties, and further promote the application potential of optical clearing to light-based noninvasive diagnostic and therapeutic techniques.

scholarly journals PARAMETRIC STUDY OF TISSUE OPTICAL CLEARING BY LOCALIZED MECHANICAL COMPRESSION USING COMBINED FINITE ELEMENT AND MONTE CARLO SIMULATION

2010 ◽  
Vol 03 (03) ◽  
pp. 203-211 ◽  
Author(s):  
WILLIAM C. VOGT ◽  
HAIOU SHEN ◽  
GE WANG ◽  
CHRISTOPHER G. RYLANDER
Keyword(s):  
Finite Element ◽  
Monte Carlo ◽  
Optical Properties ◽  
Light Transmission ◽  
Compressive Strain ◽  
Monte Carlo Model ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Tissue Optical Properties ◽  
Tissue Optical Clearing

Tissue Optical Clearing Devices (TOCDs) have been shown to increase light transmission through mechanically compressed regions of naturally turbid biological tissues. We hypothesize that zones of high compressive strain induced by TOCD pins produce localized water displacement and reversible changes in tissue optical properties. In this paper, we demonstrate a novel combined mechanical finite element model and optical Monte Carlo model which simulates TOCD pin compression of an ex vivo porcine skin sample and modified spatial photon fluence distributions within the tissue. Results of this simulation qualitatively suggest that light transmission through the skin can be significantly affected by changes in compressed tissue geometry as well as concurrent changes in tissue optical properties. The development of a comprehensive multi-domain model of TOCD application to tissues such as skin could ultimately be used as a framework for optimizing future design of TOCDs.

scholarly journals Toward Better Medical Diagnosis: Tissue Optical Clearing

2020 ◽  
Vol 2 (1) ◽  
pp. 13-21
Author(s):  
Omnia Hamdy ◽  
Rania M. Abdelazeem
Keyword(s):  
Refractive Index ◽  
Medical Diagnosis ◽  
Imaging Techniques ◽  
High Refractive Index ◽  
Biological Tissues ◽  
Optical Clearing ◽  
Research Areas ◽  
Body Tissues ◽  
Deep Imaging ◽  
Tissue Optical Clearing

Reaching efficient, safe and painless medical diagnosis procedure is a very valued goal for many research areas. Despite the great advantages of using optical imaging techniques in medical diagnosis including high safety and relative simplicity, it still suffers from relatively low resolution and penetration depth in the multiple scattering mediums such as biological tissues. Therefore, researchers began to devise ways to reduce the scattering properties of the tissue, hence increasing the imaging contrast. Optical clearing concept is introduced to do this job. This technique can reduce tissues scattering properties by using high refractive index chemicals, thus making the tissue transparent by equalizing the refractive index through that medium. In this paper, theory and techniques of optical clearing method are illustrated utilizing its benefits for deep imaging of different body tissues and organs.

Effects of Tissue Dehydration on Optical Diffuse Reflectance and Transmittance in Ex Vivo Porcine Skin

2012 ◽  
Author(s):  
William C. Vogt ◽  
Christopher G. Rylander
Keyword(s):  
Water Distribution ◽  
Diffuse Reflectance ◽  
Soft Tissues ◽  
Ex Vivo ◽  
Optical Response ◽  
Tissue Water ◽  
Optical Signals ◽  
Optical Clearing ◽  
High Degree

Soft tissues are heterogeneous materials that may be considered mixtures of water, proteins, and cells. The high degree of mismatch in refractive index between these constituents causes tissues to be highly turbid media [1]. Mechanical optical clearing is a technique for reducing tissue scattering and improving light-based diagnostics and therapeutics. Mechanical optical clearing is performed using indentation to locally modify tissue optical response, and this effect has been shown to be reversible in vivo [2]. This effect is attributed to transient changes in tissue water distribution as a result of interstitial pore flow of water due to tissue compression. This leads to the hypothesis that tissue optical response is also correlated to the tissue’s state of hydration. The goal of this study was to investigate whether or not a difference in tissue water content produces a measurable difference in tissue optical response and to correlate that response with mechanical deformation. Both diffuse reflectance and transmittance were selected as extrinsic optical signals of interest.

scholarly journals Machine learning estimation of tissue optical properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brett H. Hokr ◽  
Joel N. Bixler
Keyword(s):  
Neural Network ◽  
Optical Properties ◽  
Biological Tissues ◽  
Homogeneous Layer ◽  
In Vivo Measurement ◽  
Tissue Optical Properties ◽  
The Neural Network ◽  
Spatio Temporal ◽  
Fully Connected

AbstractDynamic, in vivo measurement of the optical properties of biological tissues is still an elusive and critically important problem. Here we develop a technique for inverting a Monte Carlo simulation to extract tissue optical properties from the statistical moments of the spatio-temporal response of the tissue by training a 5-layer fully connected neural network. We demonstrate the accuracy of the method across a very wide parameter space on a single homogeneous layer tissue model and demonstrate that the method is insensitive to parameter selection of the neural network model itself. Finally, we propose an experimental setup capable of measuring the required information in real time in an in vivo environment and demonstrate proof-of-concept level experimental results.

MCVM: MONTE CARLO MODELING OF PHOTON MIGRATION IN VOXELIZED MEDIA

2010 ◽  
Vol 03 (02) ◽  
pp. 91-102 ◽  
Author(s):  
TING LI ◽  
HUI GONG ◽  
QINGMING LUO
Keyword(s):  
Monte Carlo ◽  
Refractive Index ◽  
High Precision ◽  
Heterogeneous Media ◽  
Homogeneous Medium ◽  
Software Tool ◽  
Light Transport ◽  
Photon Migration ◽  
Monte Carlo Code ◽  
Monte Carlo Modeling

The Monte Carlo code MCML (Monte Carlo modeling of light transport in multi-layered tissue) has been the gold standard for simulations of light transport in multi-layer tissue, but it is ineffective in the presence of three-dimensional (3D) heterogeneity. New techniques have been attempted to resolve this problem, such as MCLS, which is derived from MCML, and tMCimg, which draws upon image datasets. Nevertheless, these approaches are insufficient because of their low precision or simplistic modeling. We report on the development of a novel model for photon migration in voxelized media (MCVM) with 3D heterogeneity. Voxel crossing detection and refractive-index-unmatched boundaries were considered to improve the precision and eliminate dependence on refractive-index-matched tissue. Using a semi-infinite homogeneous medium, steady-state and time-resolved simulations of MCVM agreed well with MCML, with high precision (~100%) for the total diffuse reflectance and total fractional absorption compared to those of tMCimg (< 70%). Based on a refractive-index-matched heterogeneous skin model, the results of MCVM were found to coincide with those of MCLS. Finally, MCVM was applied to a two-layered sphere with multi-inclusions, which is an example of a 3D heterogeneous media with refractive-index-unmatched boundaries. MCVM provided a reliable model for simulation of photon migration in voxelized 3D heterogeneous media, and it was developed to be a flexible and simple software tool that delivers high-precision results.

Nonlinear Optical Investigation of Biochemical Analytes in Blood Serum via Z-Scan Technique

2021 ◽  
Author(s):  
Samane Raji ◽  
Mohammad Ali Haddad ◽  
Seyed Mohammad Moshtaghioun ◽  
Zahra Dehghan
Keyword(s):  
Refractive Index ◽  
Blood Serum ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Diagnostic Procedures ◽  
Biological Tissues ◽  
Optical Characteristics ◽  
Closed Aperture ◽  
Optical Investigation ◽  
Medical Diagnoses

Background and Aims: Biomolecules' optical and nonlinear optical properties are widely used for different medical diagnoses and applications in biophotonic devices. These properties are essential in studying biological processes in living tissues. Aside from biomolecules' linear optical characteristics, their nonlinear optical characteristics have lately been considered. Materials and Methods: In this paper, the nonlinear optical responses of three biochemical analytes in blood serum, including glucose, triglycerides, and cholesterol are examined using the laser-based Z-Scan technique. Hence, different laboratory samples of blood serum with various concentrations of biochemical analytes are taken from patients for this purpose. Results: The normalized transmission curves were taken and analyzed in a closed aperture configuration of the Z-Scan technique and led to evaluating the nonlinear refractive index (n2) as an indicator of nonlinear responses of samples. The results show significant nonlinear optical behaviors of the samples under a strong electrical field of the laser, which leads to the measurement of the nonlinear refractive index (n2) of the samples with an error of less than ̴ 0.5 × 10-8 cm2/w. It is found that the values of nonlinear refractive index (n2) vary proportionally as a function of their concentration in blood serum. Conclusion: The findings of this study imply that the above sample's nonlinear optical response and, probable, those of other biological tissues might be used in medical diagnoses. In addition, the Z-Scan technique might be considered as a complementary method with other conventional diagnostic procedures due to its simplicity and quick experimental approach.

Optical Clearing of Biological Tissues: Prospects of Application for Multimodal Malignancy Diagnostics

2020 ◽  
pp. 107-131
Author(s):  
Elina A. Genina ◽  
Luís M. C. Oliveira ◽  
Alexey N. Bashkatov ◽  
Valery V. Tuchin
Keyword(s):  
Biological Tissues ◽  
Optical Clearing ◽  
Prospects Of Application

scholarly journals Molecular modeling of post-diffusion stage of biotissue optical clearing under effect of iohexol aqueous solution

2021 ◽  
Vol 2103 (1) ◽  
pp. 012048
Author(s):  
I T Shagautdinova ◽  
A M Likhter ◽  
K V Berezin ◽  
K N Dvoretsky ◽  
V V Nechaev ◽  
...  
Keyword(s):  
Experimental Data ◽  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Molecular Modeling ◽  
Biological Tissues ◽  
Optical Clearing ◽  
X Ray ◽  
Diffusion Stage ◽  
Collagen Peptide ◽  
Main Components

Abstract Interaction of iohexol (Omnipaque), an X-Ray contrast agent, with a mimetic peptide of collagen (GPH)3 as one of the main components of biological tissues has been studied with the use of methods of classical molecular dynamics (GROMACS). Complex molecular modeling of the post-diffusion stage of optical clearing allowed to evaluate such parameters as the average number of hydrogen bonds, formed between the clearing agent and collagen per unit time, and the immersion agent’s effect on changes in the collagen peptide volume. The obtained results are compared with similar results for glycerol, a polyatomic alcohol, and with the existing experimental data on the efficiency of optical clearing of these immersion agents.

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