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Lilge L, Manalac A, Weersink M, Schwiegelshohn F, Young-Schultz T, Abdalrhman AS, Wang C, Ngan A, Gu FX, Betz V, Hofmann R. Light propagation within N95 filtered face respirators: A simulation study for UVC decontamination. JOURNAL OF BIOPHOTONICS 2020; 13:e202000232. [PMID: 32888380 DOI: 10.1002/jbio.202000232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 05/24/2023]
Abstract
This study presents numerical simulations of UVC light propagation through seven different filtered face respirators (FFR) to determine their suitability for Ultraviolet germicidal inactivation (UVGI). UV propagation was modeled using the FullMonte program for two external light illuminations. The optical properties of the dominant three layers were determined using the inverse adding doubling method. The resulting fluence rate volume histograms and the lowest fluence rate recorded in the modeled volume, sometimes in the nW cm-2 , provide feedback on a respirator's suitability for UVGI and the required exposure time for a given light source. While UVGI can present an economical approach to extend an FFR's useable lifetime, it requires careful optimization of the illumination setup and selection of appropriate respirators.
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Affiliation(s)
- Lothar Lilge
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Angelica Manalac
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Madrigal Weersink
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Fynn Schwiegelshohn
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | - Tanner Young-Schultz
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | | | - Chengjin Wang
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
| | - Aldrich Ngan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Frank X Gu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
| | - Vaughn Betz
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | - Ron Hofmann
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
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Hein S, Modrić D, Westland S, Tomeček M. Objective shade matching, communication, and reproduction by combining dental photography and numeric shade quantification. J ESTHET RESTOR DENT 2020; 33:107-117. [PMID: 32840048 DOI: 10.1111/jerd.12641] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The subject of this case report is the application of a newly developed workflow for objective shade communication sans visual shade assessment or the use of shade guides. CLINICAL CONSIDERATIONS Clinical complications stemming from issues relating to esthetic integration can present a burden on the restorative team, often resulting in strenuous relationships among its members. The faithful imitation of the optical appearance of dental hard tissues with direct- and indirect restorations has been at the center of interest in a great number of publications from the realm of esthetic dentistry over the past 40 years. The present report describes a new approach to objective shade communication, by transcending the role of dental photography from its purely descriptive purpose to the level of quantification, thus abandoning the use of the established shading regimes and replacing them with a patient personal shade recipe based on the CIELAB color space instead. CONCLUSIONS Objective shade communication is possible with the eLAB system by combining numeric shade quantification with dental photography. CLINICAL SIGNIFICANCE The eLAB system presents a viable alternative to the traditional approach to shade communication and shade matching in dentistry.
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Soltaninezhad M, Bavali A, Nazifinia Z, Soleimani V. Optical anisotropy measurement in normal and cancerous tissues: backscattering technique. BIOMEDICAL OPTICS EXPRESS 2020; 11:2996-3008. [PMID: 32637237 PMCID: PMC7316004 DOI: 10.1364/boe.393079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/23/2020] [Accepted: 05/04/2020] [Indexed: 05/30/2023]
Abstract
Investigating the deformation of tissue architecture is one of the most important clinical methods for cancer diagnosis. Optical methods are now widely developed for rapid, precise, and real-time assessment of these alterations at the microscopic scale. One of the proposed methods is enhanced backscattering (EBS) technique that allows in-vivo measurement of the optical scattering characteristics. Here, EBS technique is employed to evaluate the optical anisotropy of human epithelial tissues as a measure to distinguish between normal and cancerous one. Orientation dependence of the mean scattering length is assessed in healthy and cancerous tissues of five different human organs i. e. uterus, bladder, colon, kidney, and liver. Helicity preserving channel and rotating ground glass diffuser are utilized to eliminate the polarization induced anisotropy and the background speckle noises respectively. Analysis of the backscattering cones recorded by a high-resolution CCD camera reveals the modification of the strength and degree of optical anisotropy in different tissues during cancer progression. Pathology data affirm the correlation between the experimental results and the morphological alteration of the epithelial cells in each carcinoma type. In general, tissues with fibrous constructional cells are subject to a decrease in anisotropy due to cancer, whereas those with cuboidal cells experience an increase in anisotropy. This complementary information enhances the potency of the EBS technique as a fast, non-destructive, and easily accessible tool for real-time tissue diagnosis.
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Affiliation(s)
- Mohammad Soltaninezhad
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Ali Bavali
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Ziba Nazifinia
- Department of Energy Engineering and Physics, Amirkabir University of Technology (Tehran Polytechnic), Iran
| | - Vahid Soleimani
- Department of Cancer Institute, Imam Khomeini Medical Centre, Tehran, Iran
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Abstract
This article reviews the past and current statuses of time-domain near-infrared spectroscopy (TD-NIRS) and imaging. Although time-domain technology is not yet widely employed due to its drawbacks of being cumbersome, bulky, and very expensive compared to commercial continuous wave (CW) and frequency-domain (FD) fNIRS systems, TD-NIRS has great advantages over CW and FD systems because time-resolved data measured by TD systems contain the richest information about optical properties inside measured objects. This article focuses on reviewing the theoretical background, advanced theories and methods, instruments, and studies on clinical applications for TD-NIRS including some clinical studies which used TD-NIRS systems. Major events in the development of TD-NIRS and imaging are identified and summarized in chronological tables and figures. Finally, prospects for TD-NIRS in the near future are briefly described.
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Jacucci G, Onelli OD, De Luca A, Bertolotti J, Sapienza R, Vignolini S. Coherent backscattering of light by an anisotropic biological network. Interface Focus 2018; 9:20180050. [PMID: 30603070 DOI: 10.1098/rsfs.2018.0050] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2018] [Indexed: 11/12/2022] Open
Abstract
The scattering strength of a random medium relies on the geometry and spatial distribution of its components as well as on their refractive index. Anisotropy can, therefore, play a major role in the optimization of the scattering efficiency in both biological and synthetic materials. In this study, we show that, by exploiting the coherent backscattering phenomenon, it is possible to characterize the optical anisotropy in Cyphochilus beetle scales without the need to change their orientation or their thickness. For this reason, such a static and easily accessible experimental approach is particularly suitable for the study of biological specimens. Moreover, estimation of the anisotropy in Cyphochilus beetle scales might provide inspiration for improving the scattering strength of artificial white materials.
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Affiliation(s)
- Gianni Jacucci
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Olimpia D Onelli
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Antonio De Luca
- Department of Physics, University of Calabria, via Pietro Bucci, Rende 87036, Italy.,National Research Council, Institute of Nanotechnology, via Pietro Bucci, Rende 87036, Italy
| | - Jacopo Bertolotti
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
| | - Riccardo Sapienza
- The Blackett Laboratory, Department of Physics, Imperial College London, London SW7 2BW, UK
| | - Silvia Vignolini
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Van Beers R, Kokawa M, Aernouts B, Watté R, De Smet S, Saeys W. Evolution of the bulk optical properties of bovine muscles during wet aging. Meat Sci 2018; 136:50-58. [DOI: 10.1016/j.meatsci.2017.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 09/18/2017] [Accepted: 10/16/2017] [Indexed: 11/26/2022]
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Van Beers R, Aernouts B, Reis MM, Saeys W. Anisotropic light propagation in bovine muscle tissue depends on the initial fiber orientation, muscle type and wavelength. OPTICS EXPRESS 2017; 25:22082-22095. [PMID: 29041497 DOI: 10.1364/oe.25.022082] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 08/22/2017] [Indexed: 06/07/2023]
Abstract
The effects of fiber orientation on vis/NIR light propagation were studied in three bovine muscles: biceps brachii, brachialis and soleus. Broadband light was focused onto the sample and the diffuse reflectance spot was captured using a hyperspectral camera (470-1620 nm), after which rhombuses were fitted to equi-intensity points. In samples with fibers running parallel to the measurement surface, the rhombus' major axis was oriented perpendicular to the fiber direction close to the point of illumination. However, at larger distances from the illumination spot, the major axis orientation aligned with the fiber direction. This phenomenon was found to be muscle dependent. Furthermore, the rhombus orientation was highly dependent on the sample positioning underneath the camera, especially when the muscle fibers ran parallel to the measurement surface. The bias parameter, indicating the deviation from a circular shape, was higher for samples with the fibers running parallel to the measurement surface. Moreover, clear effects of wavelength and distance from the illumination point on this parameter were observed. These results show the importance of fiber orientation when considering optical techniques for measurements on anisotropic, fibrous tissues. Moreover, the prediction of muscle fiber orientation seemed feasible, which can be of interest to the meat industry.
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Alerstam E. Anisotropic diffusive transport: connecting microscopic scattering and macroscopic transport properties. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:063202. [PMID: 25019904 DOI: 10.1103/physreve.89.063202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 06/03/2023]
Abstract
This work concerns the modeling of radiative transfer in anisotropic turbid media using diffusion theory. A theory for the relationship between microscopic scattering properties (i.e., an arbitrary differential scattering cross-section) and the macroscopic diffusion tensor, in the limit of independent scatterers, is presented. The theory is accompanied by a numerical method capable of performing the calculations. In addition, a boundary condition appropriate for modeling systems with anisotropic radiance is derived. It is shown that anisotropic diffusion theory, when based on these developments, indeed can describe radiative transfer in anisotropic turbid media. More specifically, it is reported that solutions to the anisotropic diffusion equation are in excellent agreement with Monte Carlo simulations, both in steady-state and time-domain. This stands in contrast to previous work on the topic, where inadequate boundary conditions and/or incorrect relations between microscopic scattering properties and the diffusion tensor have caused disagreement between simulations and diffusion theory. The present work thus falsify previous claims that anisotropic diffusion theory cannot describe anisotropic radiative transfer, and instead open for accurate quantitative diffusion-based modeling of anisotropic turbid materials.
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Affiliation(s)
- Erik Alerstam
- Division of Atomic Physics, Department of Physics, Lund University, P.O. Box 118, 221 00 Lund, Sweden
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Simon E, Krauter P, Kienle A. Time-resolved measurements of the optical properties of fibrous media using the anisotropic diffusion equation. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:075006. [PMID: 25055055 DOI: 10.1117/1.jbo.19.7.075006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 06/25/2014] [Indexed: 06/03/2023]
Abstract
Transmittance and reflectance from spruce wood and bovine ligamentum nuchae as two different fibrous media are examined by time-of-flight spectroscopy for varying source detector separations and several orientations of the fibers in the sample. The anisotropic diffusion theory is used to obtain the absorption coefficient and the diffusion coefficients parallel and perpendicular to the fibers. The results are compared to those obtained with the isotropic diffusion theory. It is shown that for increasing source detector separations, the retrieved optical properties change as expected from Monte Carlo simulations performed in a previous study. This confirms that the anisotropic diffusion theory yields useful results for certain experimental conditions.
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