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Niemeier R, Rogers J. Low-cost reflective Hilger-Chance refractometer used to determine Sellmeier coefficients of bulk polydimethylsiloxane. APPLIED OPTICS 2019; 58:6152-6156. [PMID: 31503940 PMCID: PMC9749033 DOI: 10.1364/ao.58.006152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/05/2019] [Indexed: 05/22/2023]
Abstract
Refractometry is important for characterizing the optical performance of materials. The refractive index can quickly be assessed using critical angle or thin-film techniques. However, these methods only assess the material surface. Measurement of bulk refractive index is performed by measuring the refracted angle of a transmitted beam but requires precision sample geometry. The method presented here avoids costly sample preparation by measuring the sample geometry and refracted angle simultaneously, using reflections from the front and back surfaces of a wedge of material. The method is demonstrated for polydimethylsiloxane prepared under a range of curing conditions, and no significant dependence was observed. Spectral dependence is characterized, and Sellmeier coefficients are reported.
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Affiliation(s)
- R. Niemeier
- Department of Biomedical Engineering & McPherson Eye Research Institute, University of Wisconsin–Madison
| | - J.D. Rogers
- Department of Biomedical Engineering & McPherson Eye Research Institute, University of Wisconsin–Madison
- Corresponding author:
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Häffner A, Krauter P, Kienle A. Density-dependent determination of scattering properties of pharmaceutical tablets using coherent backscattering spectroscopy. OPTICS EXPRESS 2018; 26:19964-19971. [PMID: 30119315 DOI: 10.1364/oe.26.019964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
We report on measurements of coherent backscattering from pharmaceutical tablets. Experimental data is analysed using the radiative transfer equation with focus on the determination of the reduced scattering coefficient μs'. The results show a good agreement with μs' determined by measuring the spatially resolved reflectance, whereat we demonstrate advantages of the coherent backscattering measurements. Furthermore, we present a correlation between μs' and tablet compression force, respectively density.
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Eshein A, Radosevich AJ, Gould B, Wu W, Konda V, Yang LW, Koons A, Feder S, Valuckaite V, Roy HK, Backman V, Nguyen TQ. Fully automated fiber-based optical spectroscopy system for use in a clinical setting. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-10. [PMID: 29981224 PMCID: PMC8357326 DOI: 10.1117/1.jbo.23.7.075003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 06/05/2018] [Indexed: 05/04/2023]
Abstract
While there are a plethora of in vivo fiber-optic spectroscopic techniques that have demonstrated the ability to detect a number of diseases in research trials with highly trained personnel familiar with the operation of experimental optical technologies, very few techniques show the same level of success in large multicenter trials. To meet the stringent requirements for a viable optical spectroscopy system to be used in a clinical setting, we developed components including an automated calibration tool, optical contact sensor for signal acquisition, and a methodology for real-time in vivo probe calibration correction. The end result is a state-of-the-art medical device that can be realistically used by a physician with spectroscopic fiber-optic probes. We show how the features of this system allow it to have excellent stability measuring two scattering phantoms in a clinical setting by clinical staff with ∼0.5 % standard deviation over 25 unique measurements on different days. In addition, we show the systems' ability to overcome many technical obstacles that spectroscopy applications often face such as speckle noise and user variability. While this system has been designed and optimized for our specific application, the system and design concepts are applicable to most in vivo fiber-optic-based spectroscopic techniques.
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Affiliation(s)
- Adam Eshein
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Andrew J. Radosevich
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Bradley Gould
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Wenli Wu
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Vani Konda
- University of Chicago Medicine, Center for Endoscopic Research and Therapeutics, Chicago, Illinois, United States
| | - Leslie W. Yang
- University of Chicago Medicine, Center for Endoscopic Research and Therapeutics, Chicago, Illinois, United States
| | - Ann Koons
- University of Chicago Medicine, Center for Endoscopic Research and Therapeutics, Chicago, Illinois, United States
| | - Seth Feder
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - Vesta Valuckaite
- University of Chicago Medicine, Center for Endoscopic Research and Therapeutics, Chicago, Illinois, United States
| | - Hemant K. Roy
- Boston Medical Center, Department of Gastroenterology, Boston, Massachusetts, United States
| | - Vadim Backman
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
| | - The-Quyen Nguyen
- Northwestern University, Department of Biomedical Engineering, Evanston, Illinois, United States
- Address all correspondence to: The-Quyen Nguyen, E-mail:
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Radosevich AJ, Mutyal NN, Eshein A, Nguyen TQ, Gould B, Rogers JD, Goldberg MJ, Bianchi LK, Yen EF, Konda V, Rex DK, Van Dam J, Backman V, Roy HK. Rectal Optical Markers for In Vivo Risk Stratification of Premalignant Colorectal Lesions. Clin Cancer Res 2015; 21:4347-4355. [PMID: 25991816 PMCID: PMC4592390 DOI: 10.1158/1078-0432.ccr-15-0136] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/04/2015] [Indexed: 02/06/2023]
Abstract
PURPOSE Colorectal cancer remains the second leading cause of cancer deaths in the United States despite being eminently preventable by colonoscopy via removal of premalignant adenomas. In order to more effectively reduce colorectal cancer mortality, improved screening paradigms are needed. Our group pioneered the use of low-coherence enhanced backscattering (LEBS) spectroscopy to detect the presence of adenomas throughout the colon via optical interrogation of the rectal mucosa. In a previous ex vivo biopsy study of 219 patients, LEBS demonstrated excellent diagnostic potential with 89.5% accuracy for advanced adenomas. The objective of the current cross-sectional study is to assess the viability of rectal LEBS in vivo. EXPERIMENTAL DESIGN Measurements from 619 patients were taken using a minimally invasive 3.4-mm diameter LEBS probe introduced into the rectum via anoscope or direct insertion, requiring approximately 1 minute from probe insertion to withdrawal. The diagnostic LEBS marker was formed as a logistic regression of the optical reduced scattering coefficient [Formula: see text] and mass density distribution factor D. RESULTS The rectal LEBS marker was significantly altered in patients harboring advanced adenomas and multiple non-advanced adenomas throughout the colon. Blinded and cross-validated test performance characteristics showed 88% sensitivity to advanced adenomas, 71% sensitivity to multiple non-advanced adenomas, and 72% specificity in the validation set. CONCLUSIONS We demonstrate the viability of in vivo LEBS measurement of histologically normal rectal mucosa to predict the presence of clinically relevant adenomas throughout the colon. The current work represents the next step in the development of rectal LEBS as a tool for colorectal cancer risk stratification.
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Affiliation(s)
| | - Nikhil N. Mutyal
- Biomedical Engineering Department, Northwestern University, Evanston, Il
| | - Adam Eshein
- Biomedical Engineering Department, Northwestern University, Evanston, Il
| | - The-Quyen Nguyen
- Biomedical Engineering Department, Northwestern University, Evanston, Il
| | - Bradley Gould
- Biomedical Engineering Department, Northwestern University, Evanston, Il
| | - Jeremy D. Rogers
- Biomedical Engineering Department, University of Wisconsin, Madison, Wisconsin
| | - Michael J Goldberg
- Department of Medicine, NorthShore University HealthSystems, Evanston, Il
| | - Laura K Bianchi
- Department of Medicine, NorthShore University HealthSystems, Evanston, Il
| | - Eugene F. Yen
- Department of Medicine, NorthShore University HealthSystems, Evanston, Il
| | - Vani Konda
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL
| | - Douglas K. Rex
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jacques Van Dam
- Advanced Digestive Health Center, University of Southern California Medical Center, Los Angeles, CA
| | - Vadim Backman
- Biomedical Engineering Department, Northwestern University, Evanston, Il
| | - Hemant K. Roy
- Department of Medicine, Boston University, Boston, Massachusetts
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Mutyal NN, Radosevich AJ, Bajaj S, Konda V, Siddiqui UD, Waxman I, Goldberg MJ, Rogers JD, Gould B, Eshein A, Upadhye S, Koons A, Gonzalez-Haba Ruiz M, Roy HK, Backman V. In vivo risk analysis of pancreatic cancer through optical characterization of duodenal mucosa. Pancreas 2015; 44:735-41. [PMID: 25906443 PMCID: PMC4464933 DOI: 10.1097/mpa.0000000000000340] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/17/2014] [Indexed: 12/18/2022]
Abstract
OBJECTIVES To reduce pancreatic cancer mortality, a paradigm shift in cancer screening is needed. Our group pioneered the use of low-coherence enhanced backscattering (LEBS) spectroscopy to predict the presence of pancreatic cancer by interrogating the duodenal mucosa. A previous ex vivo study (n = 203) demonstrated excellent diagnostic potential: sensitivity, 95%; specificity, 71%; and accuracy, 85%. The objective of the current case-control study was to evaluate this approach in vivo. METHODS We developed a novel endoscope-compatible fiber-optic probe to measure LEBS in the periampullary duodenum of 41 patients undergoing upper endoscopy. This approach enables minimally invasive detection of the ultrastructural consequences of pancreatic field carcinogenesis. RESULTS The LEBS parameters and optical properties were significantly altered in patients harboring adenocarcinomas (including early-stage) throughout the pancreas relative to healthy controls. Test performance characteristics were excellent with sensitivity = 78%, specificity = 85%, and accuracy = 81%. Moreover, the LEBS prediction rule was not confounded by patients' demographics. CONCLUSION We demonstrate the feasibility of in vivo measurement of histologically normal duodenal mucosa to predict the presence of adenocarcinoma throughout the pancreas. This represents the next step in establishing duodenal LEBS analysis as a prescreening technique that identifies clinically asymptomatic patients who are at elevated risk of PC.
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Affiliation(s)
- Nikhil N. Mutyal
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Andrew J. Radosevich
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Shailesh Bajaj
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Vani Konda
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Uzma D. Siddiqui
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Irving Waxman
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Michael J. Goldberg
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Jeremy D. Rogers
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Bradley Gould
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Adam Eshein
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Sudeep Upadhye
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Ann Koons
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Mariano Gonzalez-Haba Ruiz
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Hemant K. Roy
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
| | - Vadim Backman
- From the *Department of Biomedical Engineering, Northwestern University; †Department of Internal Medicine, NorthShore University HealthSystems, Evanston; ‡Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL; and §Department of Gastroenterology, Boston Medical Center, Boston, MA
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Buccal spectral markers for lung cancer risk stratification. PLoS One 2014; 9:e110157. [PMID: 25299667 PMCID: PMC4192585 DOI: 10.1371/journal.pone.0110157] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 09/04/2014] [Indexed: 12/11/2022] Open
Abstract
Lung cancer remains the leading cause of cancer deaths in the US with >150,000 deaths per year. In order to more effectively reduce lung cancer mortality, more sophisticated screening paradigms are needed. Previously, our group demonstrated the use of low-coherence enhanced backscattering (LEBS) spectroscopy to detect and quantify the micro/nano-architectural correlates of colorectal and pancreatic field carcinogenesis. In the lung, the buccal (cheek) mucosa has been suggested as an excellent surrogate site in the “field of injury”. We, therefore, wanted to assess whether LEBS could similarly sense the presence of lung. To this end, we applied a fiber-optic LEBS probe to a dataset of 27 smokers without diagnosed lung cancer (controls) and 46 with lung cancer (cases), which was divided into a training and a blinded validation set (32 and 41 subjects, respectively). LEBS readings of the buccal mucosa were taken from the oral cavity applying gentle contact. The diagnostic LEBS marker was notably altered in patients harboring lung cancer compared to smoking controls. The prediction rule developed on training set data provided excellent diagnostics with 94% sensitivity, 80% specificity, and 95% accuracy. Applying the same threshold to the blinded validation set yielded 79% sensitivity and 83% specificity. These results were not confounded by patient demographics or impacted by cancer type or location. Moreover, the prediction rule was robust across all stages of cancer including stage I. We envision the use of LEBS as the first part of a two-step paradigm shift in lung cancer screening in which patients with high LEBS risk markers are funnelled into more invasive screening for confirmation.
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Mutyal NN, Radosevich A, Gould B, Rogers JD, Gomes A, Turzhitsky V, Backman V. A fiber optic probe design to measure depth-limited optical properties in-vivo with low-coherence enhanced backscattering (LEBS) spectroscopy. OPTICS EXPRESS 2012; 20:19643-57. [PMID: 23037017 PMCID: PMC3635466 DOI: 10.1364/oe.20.019643] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 08/03/2012] [Accepted: 08/06/2012] [Indexed: 05/20/2023]
Abstract
Low-coherence enhanced backscattering (LEBS) spectroscopy is an angular resolved backscattering technique that is sensitive to sub-diffusion light transport length scales in which information about scattering phase function is preserved. Our group has shown the ability to measure the spatial backscattering impulse response function along with depth-selective optical properties in tissue ex-vivo using LEBS. Here we report the design and implementation of a lens-free fiber optic LEBS probe capable of providing depth-limited measurements of the reduced scattering coefficient in-vivo. Experimental measurements combined with Monte Carlo simulation of scattering phantoms consisting of polystyrene microspheres in water are used to validate the performance of the probe. Additionally, depth-limited capabilities are demonstrated using Monte Carlo modeling and experimental measurements from a two-layered phantom.
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Affiliation(s)
- Nikhil N. Mutyal
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Andrew Radosevich
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Bradley Gould
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Jeremy D. Rogers
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Andrew Gomes
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Vladimir Turzhitsky
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston IL 60208, USA
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Radosevich AJ, Rogers JD, Turzhitsky V, Mutyal NN, Yi J, Roy HK, Backman V. Polarized Enhanced Backscattering Spectroscopy for Characterization of Biological Tissues at Subdiffusion Length-scales. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2012; 18:1313-1325. [PMID: 24163574 PMCID: PMC3806115 DOI: 10.1109/jstqe.2011.2173659] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Since the early 1980's, the enhanced backscattering (EBS) phenomenon has been well-studied in a large variety of non-biological materials. Yet, until recently the use of conventional EBS for the characterization of biological tissue has been fairly limited. In this work we detail the unique ability of EBS to provide spectroscopic, polarimetric, and depth-resolved characterization of biological tissue using a simple backscattering instrument. We first explain the experimental and numerical procedures used to accurately measure and model the full azimuthal EBS peak shape in biological tissue. Next we explore the peak shape and height dependencies for different polarization channels and spatial coherence of illumination. We then illustrate the extraordinary sensitivity of EBS to the shape of the scattering phase function using suspensions of latex microspheres. Finally, we apply EBS to biological tissue samples in order to measure optical properties and observe the spatial length-scales at which backscattering is altered in early colon carcinogenesis.
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Affiliation(s)
- Andrew J Radosevich
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208 USA
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