1
|
Chang S, Krzyzanowska H, Bowden AK. Label-Free Optical Technologies to Enhance Noninvasive Endoscopic Imaging of Early-Stage Cancers. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2024; 17:289-311. [PMID: 38424030 DOI: 10.1146/annurev-anchem-061622-014208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
White light endoscopic imaging allows for the examination of internal human organs and is essential in the detection and treatment of early-stage cancers. To facilitate diagnosis of precancerous changes and early-stage cancers, label-free optical technologies that provide enhanced malignancy-specific contrast and depth information have been extensively researched. The rapid development of technology in the past two decades has enabled integration of these optical technologies into clinical endoscopy. In recent years, the significant advantages of using these adjunct optical devices have been shown, suggesting readiness for clinical translation. In this review, we provide an overview of the working principles and miniaturization considerations and summarize the clinical and preclinical demonstrations of several such techniques for early-stage cancer detection. We also offer an outlook for the integration of multiple technologies and the use of computer-aided diagnosis in clinical endoscopy.
Collapse
Affiliation(s)
- Shuang Chang
- 1Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Tennessee, USA;
- 2Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Halina Krzyzanowska
- 1Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Tennessee, USA;
- 2Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Audrey K Bowden
- 1Vanderbilt Biophotonics Center, Vanderbilt University, Nashville, Tennessee, USA;
- 2Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
- 3Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, Tennessee, USA
| |
Collapse
|
2
|
Steelman ZA, Ho DS, Chu KK, Wax A. Light scattering methods for tissue diagnosis. OPTICA 2019; 6:479-489. [PMID: 33043100 PMCID: PMC7544148 DOI: 10.1364/optica.6.000479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Light scattering has become a common biomedical research tool, enabling diagnostic sensitivity to myriad tissue alterations associated with disease. Light-tissue interactions are particularly attractive for diagnostics due to the variety of contrast mechanisms that can be used, including spectral, angle-resolved, and Fourier-domain detection. Photonic diagnostic tools offer further benefit in that they are non-ionizing, non-invasive, and give real-time feedback. In this review, we summarize recent innovations in light scattering technologies, with a focus on clinical achievements over the previous ten years.
Collapse
|
3
|
Ruderman S, Eshein A, Valuckaite V, Dougherty U, Almoghrabi A, Gomes A, Singh A, Pabla B, Roy HK, Hart J, Bissonnette M, Konda V, Backman V. Early increase in blood supply (EIBS) is associated with tumor risk in the Azoxymethane model of colon cancer. BMC Cancer 2018; 18:814. [PMID: 30103733 PMCID: PMC6090821 DOI: 10.1186/s12885-018-4709-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 07/31/2018] [Indexed: 01/20/2023] Open
Abstract
Background The present study aimed to investigate the role of blood supply in early tumorigenesis in colorectal cancer. We leveraged the renin angiotensin system (RAS) to alter colonic blood supply and determine the effect on tumor initiation and progression. Methods To test the effect of blood supply on tumorigenesis, 53 male A/J mice were randomly assigned to one of three RAS modulation groups and one of two AOM treatments. The RAS modulation groups were I) water (RAS-unmodulated) as a control group, II) angiotensin-II and III) the angiotensin receptor blocker, Losartan. The mice in each group were then randomly split into either the saline control condition or the AOM-treated condition in which tumors were induced with a standard protocol of serial azoxymethane (AOM) injections. To monitor microvascular changes in the rectal mucosa during the study, we used confocal laser endomicroscopy (CLE) with FITC-Dextran for in-vivo imaging of vessels and polarization-gated spectroscopy (PGS) to quantify rectal hemoglobin concentration ([Hb]) and blood vessel radius (BVR). Results At 12 weeks post-AOM injections and before tumor formation, CLE images revealed many traditional hallmarks of angiogenesis including vessel dilation, loss of co-planarity, irregularity, and vessel sprouting in the pericryptal capillaries of the rectal mucosa in AOM-Water tumor bearing mice. PGS measurements at the same time-point showed increased rectal [Hb] and decreased BVR. At later time points, CLE images showed pronounced angiogenic features including irregular networks throughout the colon. Notably, the AOM-Losartan mice had significantly lower tumor multiplicity and did not exhibit the same angiogenic features observed with CLE, or the increase in [Hb] or decrease in BVR measured with PGS. The AOM-AngII mice did not have any significant trends. Conclusion In-vivo PGS measurements of rectal colonic blood supply as well as CLE imaging revealed angiogenic disruptions to the capillary network prior to tumor formation. Losartan demonstrated an effective way to mitigate the changes to blood supply during tumorigenesis and reduce tumor multiplicity. These effects can be used in future studies to understand the early vessel changes observed.
Collapse
Affiliation(s)
- Sarah Ruderman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Adam Eshein
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Vesta Valuckaite
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Urszula Dougherty
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Anas Almoghrabi
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Andrew Gomes
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Ajaypal Singh
- Department of Gastroenterology, Rush University, Chicago, IL, 60612, USA
| | - Baldeep Pabla
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Hemant K Roy
- Department of Gastroenterology, Boston Medical Center, Boston, MA, 02118, USA
| | - John Hart
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Marc Bissonnette
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Vani Konda
- Center for Endoscopic Research and Therapeutics, University of Chicago Medicine, Chicago, IL, 60637, USA
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
| |
Collapse
|
4
|
Carvalho S, Gueiral N, Nogueira E, Henrique R, Oliveira L, Tuchin VV. Glucose diffusion in colorectal mucosa-a comparative study between normal and cancer tissues. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:91506. [PMID: 28241323 DOI: 10.1117/1.jbo.22.9.091506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/31/2017] [Indexed: 05/21/2023]
Abstract
Colorectal carcinoma is a major health concern worldwide and its high incidence and mortality require accurate screening methods. Following endoscopic examination, polyps must be removed for histopathological characterization. Aiming to contribute to the improvement of current endoscopy methods of colorectal carcinoma screening or even for future development of laser treatment procedures, we studied the diffusion properties of glucose and water in colorectal healthy and pathological mucosa. These parameters characterize the tissue dehydration and the refractive index matching mechanisms of optical clearing (OC). We used ex vivo tissues to measure the collimated transmittance spectra and thickness during treatments with OC solutions containing glucose in different concentrations. These time dependencies allowed for estimating the diffusion time and diffusion coefficient values of glucose and water in both types of tissues. The measured diffusion times for glucose in healthy and pathological mucosa samples were 299.2 ± 4.7 ?? s and 320.6 ± 10.6 ?? s for 40% and 35% glucose concentrations, respectively. Such a difference indicates a slower glucose diffusion in cancer tissues, which originate from their ability to trap far more glucose than healthy tissues. We have also found a higher free water content in cancerous tissue that is estimated as 64.4% instead of 59.4% for healthy mucosa.
Collapse
Affiliation(s)
- Sónia Carvalho
- Portuguese Oncology Institute of Porto, Department of Pathology and Cancer Biology and Epigenetics Group-Research Centre, Porto, Portugal
| | - Nuno Gueiral
- Polytechnic of Porto, School of Engineering, Physics Department, Porto, PortugalcCentre of Innovation in Engineering and Industrial Technology, ISEP, Porto, Portugal
| | - Elisabete Nogueira
- Polytechnic of Porto, School of Engineering, Physics Department, Porto, PortugalcCentre of Innovation in Engineering and Industrial Technology, ISEP, Porto, Portugal
| | - Rui Henrique
- Portuguese Oncology Institute of Porto, Department of Pathology and Cancer Biology and Epigenetics Group-Research Centre, Porto, PortugaldUniversity of Porto (ICBAS-UP), Institute of Biomedical Sciences Abel Salazar, Department of Pathology and Molecular Immunology, Porto, Portugal
| | - Luís Oliveira
- Polytechnic of Porto, School of Engineering, Physics Department, Porto, PortugalcCentre of Innovation in Engineering and Industrial Technology, ISEP, Porto, Portugal
| | - Valery V Tuchin
- Saratov National Research State University, Research-Educational Institute of Optics and Biophotonics, Saratov, RussiafPrecision Mechanics and Control Institute of the Russian Academy of Sciences, Laboratory of Laser Diagnostics of Technical and Living Systems, Saratov, RussiagNational Research Tomsk State University, Interdisciplinary Laboratory of Biophotonics, Tomsk, Russia
| |
Collapse
|
5
|
MCCLATCHY DAVIDM, RIZZO ELIZABETHJ, WELLS WENDYA, CHENEY PHILIPP, HWANG JEESEONGC, PAULSEN KEITHD, POGUE BRIANW, KANICK STEPHENC. Wide-field quantitative imaging of tissue microstructure using sub-diffuse spatial frequency domain imaging. OPTICA 2016; 3:613-621. [PMID: 27547790 PMCID: PMC4989924 DOI: 10.1364/optica.3.000613] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Localized measurements of scattering in biological tissue provide sensitivity to microstructural morphology but have limited utility to wide-field applications, such as surgical guidance. This study introduces sub-diffusive spatial frequency domain imaging (sd-SFDI), which uses high spatial frequency illumination to achieve wide-field sampling of localized reflectances. Model-based inversion recovers macroscopic variations in the reduced scattering coefficient [Formula: see text] and the phase function backscatter parameter (γ). Measurements in optical phantoms show quantitative imaging of user-tuned phase-function-based contrast with accurate decoupling of parameters that define both the density and the size-scale distribution of scatterers. Measurements of fresh ex vivo breast tissue samples revealed, for the first time, unique clustering of sub-diffusive scattering properties for different tissue types. The results support that sd-SFDI provides maps of microscopic structural biomarkers that cannot be obtained with diffuse wide-field imaging and characterizes spatial variations not resolved by point-based optical sampling.
Collapse
Affiliation(s)
- DAVID M. MCCLATCHY
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, USA
| | - ELIZABETH J. RIZZO
- Department of Pathology, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
| | - WENDY A. WELLS
- Department of Pathology, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
- Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
| | - PHILIP P. CHENEY
- Quantum Elecromagnetics Division, National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - JEESEONG C. HWANG
- Quantum Elecromagnetics Division, National Institute of Standards and Technology, 325 Broadway Street, Boulder, Colorado 80305, USA
| | - KEITH D. PAULSEN
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, USA
- Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
| | - BRIAN W. POGUE
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, USA
- Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
| | - STEPHEN C. KANICK
- Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, USA
- Norris Cotton Cancer Center, Dartmouth Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03756, USA
- Corresponding author:
| |
Collapse
|
6
|
Radosevich AJ, Eshein A, Nguyen TQ, Backman V. Subdiffusion reflectance spectroscopy to measure tissue ultrastructure and microvasculature: model and inverse algorithm. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:097002. [PMID: 26414387 PMCID: PMC4963470 DOI: 10.1117/1.jbo.20.9.097002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/31/2015] [Indexed: 05/19/2023]
Abstract
Reflectance measurements acquired from within the subdiffusion regime (i.e., lengthscales smaller than a transport mean free path) retain much of the original information about the shape of the scattering phase function. Given this sensitivity, many models of subdiffusion regime light propagation have focused on parametrizing the optical signal through various optical and empirical parameters. We argue, however, that a more useful and universal way to characterize such measurements is to focus instead on the fundamental physical properties, which give rise to the optical signal. This work presents the methodologies that used to model and extract tissue ultrastructural and microvascular properties from spatially resolved subdiffusion reflectance spectroscopy measurements. We demonstrate this approach using ex-vivo rat tissue samples measured by enhanced backscattering spectroscopy.
Collapse
Affiliation(s)
- Andrew J. Radosevich
- Northwestern University, Biomedical Engineering, Tech E310, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Address all correspondence to: Andrew J. Radosevich, E-mail:
| | - Adam Eshein
- Northwestern University, Biomedical Engineering, Tech E310, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - The-Quyen Nguyen
- Northwestern University, Biomedical Engineering, Tech E310, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Vadim Backman
- Northwestern University, Biomedical Engineering, Tech E310, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| |
Collapse
|
7
|
Kanick SC, McClatchy DM, Krishnaswamy V, Elliott JT, Paulsen KD, Pogue BW. Sub-diffusive scattering parameter maps recovered using wide-field high-frequency structured light imaging. BIOMEDICAL OPTICS EXPRESS 2014; 5:3376-90. [PMID: 25360357 PMCID: PMC4206309 DOI: 10.1364/boe.5.003376] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/22/2014] [Accepted: 08/25/2014] [Indexed: 05/03/2023]
Abstract
This study investigates the hypothesis that structured light reflectance imaging with high spatial frequency patterns [Formula: see text] can be used to quantitatively map the anisotropic scattering phase function distribution [Formula: see text] in turbid media. Monte Carlo simulations were used in part to establish a semi-empirical model of demodulated reflectance ([Formula: see text]) in terms of dimensionless scattering [Formula: see text] and [Formula: see text], a metric of the first two moments of the [Formula: see text] distribution. Experiments completed in tissue-simulating phantoms showed that simultaneous analysis of [Formula: see text] spectra sampled at multiple [Formula: see text] in the frequency range [0.05-0.5] [Formula: see text] allowed accurate estimation of both [Formula: see text] in the relevant tissue range [0.4-1.8] [Formula: see text], and [Formula: see text] in the range [1.4-1.75]. Pilot measurements of a healthy volunteer exhibited [Formula: see text]-based contrast between scar tissue and surrounding normal skin, which was not as apparent in wide field diffuse imaging. These results represent the first wide-field maps to quantify sub-diffuse scattering parameters, which are sensitive to sub-microscopic tissue structures and composition, and therefore, offer potential for fast diagnostic imaging of ultrastructure on a size scale that is relevant to surgical applications.
Collapse
|
8
|
Gomes AJ, Wolfsen HC, Wallace MB, Cayer FK, Backman V. Monte Carlo model of the depolarization of backscattered linearly polarized light in the sub-diffusion regime. OPTICS EXPRESS 2014; 22:5325-5340. [PMID: 24663873 DOI: 10.1364/oe.22.005325] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a predictive model of the depolarization ratio of backscattered linearly polarized light from spatially continuous refractive index media that is applicable to the sub-diffusion regime of light scattering. Using Monte Carlo simulations, we derived a simple relationship between the depolarization ratio and both the sample optical properties and illumination-collection geometry. Our model was validated on tissue simulating phantoms and found to be in good agreement. We further show the utility of this model by demonstrating its use for measuring the depolarization length from biological tissue in vivo. We expect our results to aid in the interpretation of the depolarization ratio from sub-diffusive reflectance measurements.
Collapse
|
9
|
van Leeuwen–van Zaane F, Gamm UA, van Driel PBAA, Snoeks TJA, de Bruijn HS, van der Ploeg–van den Heuvel A, Mol IM, Löwik CWGM, Sterenborg HJCM, Amelink A, Robinson DJ. In vivo quantification of the scattering properties of tissue using multi-diameter single fiber reflectance spectroscopy. BIOMEDICAL OPTICS EXPRESS 2013; 4:696-708. [PMID: 23667786 PMCID: PMC3646597 DOI: 10.1364/boe.4.000696] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/20/2013] [Accepted: 02/23/2013] [Indexed: 05/19/2023]
Abstract
Multi diameter single fiber reflectance (MDSFR) spectroscopy is a non-invasive optical technique based on using multiple fibers of different diameters to determine both the reduced scattering coefficient (μs') and a parameter γ that is related to the angular distribution of scattering, where γ = (1-g2)/(1-g1) and g1 and g2 the first and second moment of the phase function, respectively. Here we present the first in vivo MDSFR measurements of μs'(λ) and γ(λ) and their wavelength dependence. MDSFR is performed on nineteen mice in four tissue types including skin, liver, normal tongue and in an orthotopic oral squamous cell carcinoma. The wavelength-dependent slope of μs'(λ) (scattering power) is significantly higher for tongue and skin than for oral cancer and liver. The reduced scattering coefficient at 800 nm of oral cancer is significantly higher than of normal tongue and liver. Gamma generally increases with increasing wavelength; for tumor it increases monotonically with wavelength, while for skin, liver and tongue γ(λ) reaches a plateau or even decreases for longer wavelengths. The mean γ(λ) in the wavelength range 400-850 nm is highest for liver (1.87 ± 0.07) and lowest for skin (1.37 ± 0.14). Gamma of tumor and normal tongue falls in between these values where tumor exhibits a higher average γ(λ) (1.72 ± 0.09) than normal tongue (1.58 ± 0.07). This study shows the potential of using light scattering spectroscopy to optically characterize tissue in vivo.
Collapse
Affiliation(s)
- F. van Leeuwen–van Zaane
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | - U. A. Gamm
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | | | - T. J. A. Snoeks
- Department of Radiology, Leiden University Medical Centre,
Leiden, The Netherlands
| | - H. S. de Bruijn
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | - A. van der Ploeg–van den Heuvel
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | - I. M. Mol
- Department of Radiology, Leiden University Medical Centre,
Leiden, The Netherlands
| | - C. W. G. M. Löwik
- Department of Radiology, Leiden University Medical Centre,
Leiden, The Netherlands
| | - H. J. C. M. Sterenborg
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | - A. Amelink
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
| | - D. J. Robinson
- Department of Radiation Oncology, Center for Optical Diagnostics
and Therapy, Postgraduate School Molecular Medicine, Erasmus MC, P.O. box 2040, 3000 CA
Rotterdam, The Netherlands
- Department of Dermatology, Erasmus MC Rotterdam, The
Netherlands
| |
Collapse
|
10
|
Yi J, Radosevich AJ, Rogers JD, Norris SCP, Çapoğlu İR, Taflove A, Backman V. Can OCT be sensitive to nanoscale structural alterations in biological tissue? OPTICS EXPRESS 2013; 21:9043-59. [PMID: 23571994 PMCID: PMC3641881 DOI: 10.1364/oe.21.009043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/07/2013] [Accepted: 03/11/2013] [Indexed: 05/18/2023]
Abstract
Exploration of nanoscale tissue structures is crucial in understanding biological processes. Although novel optical microscopy methods have been developed to probe cellular features beyond the diffraction limit, nanometer-scale quantification remains still inaccessible for in situ tissue. Here we demonstrate that, without actually resolving specific geometrical feature, OCT can be sensitive to tissue structural properties at the nanometer length scale. The statistical mass-density distribution in tissue is quantified by its autocorrelation function modeled by the Whittle-Mateŕn functional family. By measuring the wavelength-dependent backscattering coefficient μb(λ) and the scattering coefficient μs, we introduce a technique called inverse spectroscopic OCT (ISOCT) to quantify the mass-density correlation function. We find that the length scale of sensitivity of ISOCT ranges from ~30 to ~450 nm. Although these sub-diffractional length scales are below the spatial resolution of OCT and therefore not resolvable, they are nonetheless detectable. The sub-diffractional sensitivity is validated by 1) numerical simulations; 2) tissue phantom studies; and 3) ex vivo colon tissue measurements cross-validated by scanning electron microscopy (SEM). Finally, the 3D imaging capability of ISOCT is demonstrated with ex vivo rat buccal and human colon samples.
Collapse
Affiliation(s)
- Ji Yi
- Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Rd.,Evanston, IL 60208, USA.
| | | | | | | | | | | | | |
Collapse
|
11
|
Backman V, Roy HK. Advances in biophotonics detection of field carcinogenesis for colon cancer risk stratification. J Cancer 2013; 4:251-61. [PMID: 23459690 PMCID: PMC3584838 DOI: 10.7150/jca.5838] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/11/2013] [Indexed: 02/06/2023] Open
Abstract
The process of neoplastic transformation of the colon involves a progression through hyperproliferative epithelium through the aberrant crypt foci→small adenoma→large adenoma→invasive cancer→metastatic disease. These are orchestrated by sequential genetic and epigenetic events which provide the underpinnings of cellular alterations such as early induction in proliferation/suppression of apoptosis, along with the late stage increase in invasiveness. Colorectal cancer (CRC) averages 49-111 mutations per tumor encompassing 10-15 critical signaling pathways[1]. Accumulating such a high number of mutations requires a fertile mutational field, which is the hallmark of colon carcinogenesis. While genetic susceptibility to colorectal cancer is well-known, at least half of the risk is believed to be due to exogeneous factors (e.g., obesity, diet, exercise). Understanding these risk factors represents a promising mode of tailoring screening modality and intensity. However, previous attempts using these factors (i.e., NCI risk calculator) have only been modestly successful with an area under receiver operating characteristics (ROC) curve (AUC) of just 0.61. One of the most important concepts is that risk is the interaction between these genetic and environmental components and is driven by the variety of polymorphisms. Thus, predicting risk is difficult given the complexity. On the other hand, the colonic mucosa represents the end product of the complex interplay between these multiple factors. The power of field carcinogenesis is that it reflects this interplay between genetics and environment.
Collapse
Affiliation(s)
- Vadim Backman
- 1. Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
| | | |
Collapse
|
12
|
Gomes AJ, Backman V. Analytical light reflectance models for overlapping illumination and collection area geometries. APPLIED OPTICS 2012. [PMID: 23207312 PMCID: PMC3655705 DOI: 10.1364/ao.51.008013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Several biomedical applications, such as detection of dysplasia, require selective interrogation of superficial tissue structures less than a few hundred micrometers thick. Techniques and methods have been developed to limit the penetration depth of light in tissue, including the design of systems such as fiber-optic probes that have overlapping illumination and collection areas on the tissue surface. For such geometries, the diffusion approximation to the light-transport equation typically does not apply, and as a result there is no general model to extract tissue optical properties from reflectance measurements. In the current study, we employ Monte Carlo (MC) simulations to develop simple and compact analytical models for the light reflectance from these overlapping geometries. These models incorporate the size of the illumination and collection areas, the collection angle, the polarization of the incident light, and the optical properties of the sample. Moreover, these MC simulations use the Whittle-Matérn model to describe scattering from spatially continuous refractive index media such as tissue, which is more general than models based on the conventionally used Henyey-Greenstein model. We validated these models on tissue-simulating phantoms. The models developed herein will facilitate the extraction of optical properties and aid in the design of optical systems employing overlapping illumination and collection areas, including fiber-optic probes for in vivo tissue diagnosis.
Collapse
|
13
|
Radosevich AJ, Rogers JD, Capoğlu IR, Mutyal NN, Pradhan P, Backman V. Open source software for electric field Monte Carlo simulation of coherent backscattering in biological media containing birefringence. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:115001. [PMID: 23123973 PMCID: PMC3487050 DOI: 10.1117/1.jbo.17.11.115001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
ABSTRACT. We present an open source electric field tracking Monte Carlo program to model backscattering in biological media containing birefringence, with computation of the coherent backscattering phenomenon as an example. These simulations enable the modeling of tissue scattering as a statistically homogeneous continuous random media under the Whittle-Matérn model, which includes the Henyey-Greenstein phase function as a special case, or as a composition of discrete spherical scatterers under Mie theory. The calculation of the amplitude scattering matrix for the above two cases as well as the implementation of birefringence using the Jones N-matrix formalism is presented. For ease of operator use and data processing, our simulation incorporates a graphical user interface written in MATLAB to interact with the underlying C code. Additionally, an increase in computational speed is achieved through implementation of message passing interface and the semi-analytical approach. Finally, we provide demonstrations of the results of our simulation for purely scattering media and scattering media containing linear birefringence.
Collapse
Affiliation(s)
- Andrew J Radosevich
- Northwestern University, Biomedical Engineering Department, Tech E310, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
| | | | | | | | | | | |
Collapse
|