1
|
Bai Y, Cai S, Xie S, Dong B. High-resolution optical coherence tomography using gapped spectrum and real-valued iterative adaptive approach. OPTICS EXPRESS 2023; 31:5519-5530. [PMID: 36823830 DOI: 10.1364/oe.481206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
Optical coherence tomography (OCT) is a powerful imaging technique that is capable of imaging cross-sectional structures with micrometer resolution. After combining with phase-sensitive detection, it can sense small changes in the physical quantities inside an object. In OCT, axial resolution is generally improved by expanding the bandwidth of the light source. However, when the bandwidth is expanded discontinuously, the wavelength gap induces abnormal sidelobes when estimating OCT signals in the depth domain. This problem can lead to poor axial resolution. Herein, we present a method based on a real-valued iterative adaptive approach (RIAA) to achieve a high axial resolution under a discontinuous bandwidth condition. The method uses a weighted matrix to suppress the abnormal sidelobes caused by the wavelength gap and, therefore, can realize high-resolution measurements. A single-reflector OCT spectrum was first measured for validation, and its amplitude in the depth domain was estimated using different methods. The results indicate that the RIAA had the best capability of suppressing abnormal sidelobes, thereby achieving a high axial resolution. In addition, cross-sectional images and phase-difference maps of three different samples were measured. A comparison of the results validated the practical value of this method.
Collapse
|
2
|
Song G, Jelly ET, Chu KK, Kendall WY, Wax A. A review of low-cost and portable optical coherence tomography. PROGRESS IN BIOMEDICAL ENGINEERING (BRISTOL, ENGLAND) 2021; 3:032002. [PMID: 37645660 PMCID: PMC10465117 DOI: 10.1088/2516-1091/abfeb7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Optical coherence tomography (OCT) is a powerful optical imaging technique capable of visualizing the internal structure of biological tissues at near cellular resolution. For years, OCT has been regarded as the standard of care in ophthalmology, acting as an invaluable tool for the assessment of retinal pathology. However, the costly nature of most current commercial OCT systems has limited its general accessibility, especially in low-resource environments. It is therefore timely to review the development of low-cost OCT systems as a route for applying this technology to population-scale disease screening. Low-cost, portable and easy to use OCT systems will be essential to facilitate widespread use at point of care settings while ensuring that they offer the necessary imaging performances needed for clinical detection of retinal pathology. The development of low-cost OCT also offers the potential to enable application in fields outside ophthalmology by lowering the barrier to entry. In this paper, we review the current development and applications of low-cost, portable and handheld OCT in both translational and research settings. Design and cost-reduction techniques are described for general low-cost OCT systems, including considerations regarding spectrometer-based detection, scanning optics, system control, signal processing, and the role of 3D printing technology. Lastly, a review of clinical applications enabled by low-cost OCT is presented, along with a detailed discussion of current limitations and outlook.
Collapse
Affiliation(s)
- Ge Song
- Author to whom any correspondence should be addressed.
| | | | - Kengyeh K Chu
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Wesley Y Kendall
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| | - Adam Wax
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, United States of America
| |
Collapse
|
3
|
Sahoo GR, Dey R, Das N, Ghosh N, Pradhan A. Two dimensional multifractal detrended fluctuation analysis of low coherence images for diagnosis of cervical pre-cancer. Biomed Phys Eng Express 2020; 6:025011. [PMID: 33438637 DOI: 10.1088/2057-1976/ab6e17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We report detection of cervical pre-cancer through their low coherence images by applying two dimensional multifractal detrended fluctuation analysis. Low coherent backscattered images of pre-cancerous cervical tissue sections were captured using a common path interferometric setup. The captured images contain both depth and lateral information of the spatial variation in refractive index (RI) occurring with progression of cervical pre-cancer. A two-dimensional multifractal detrended fluctuation analysis (2D MFDFA) was applied on these low coherent images to study the variations occurring in their fractal nature. Long-range correlations were observed in the RI fluctuations and the strength of multifractality was found to be stronger for higher grades of cervical pre-cancer. A combination of derived multifractal parameters, namely, the generalized Hurst exponent and width of singularity spectrum showed clear differences among the different grades of pre-cancers. Normal, CIN-I and CIN-II were clearly discriminated by application of support vector machine (SVM) using radial Bessel function (RBF) kernel. The specificities and sensitivities between normal and CIN-I, CIN-I and CIN-II and normal and CIN-II were found to be 94%, 88% and 93%, 96% and 98%, 100% respectively.
Collapse
|
4
|
Borycki D, Hamkało M, Nowakowski M, Szkulmowski M, Wojtkowski M. Spatiotemporal optical coherence (STOC) manipulation suppresses coherent cross-talk in full-field swept-source optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2019; 10:2032-2054. [PMID: 31086716 PMCID: PMC6485009 DOI: 10.1364/boe.10.002032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 05/05/2023]
Abstract
Full-field swept-source optical coherence tomography (FF-SS-OCT) provides high-resolution depth-resolved images of the sample by parallel Fourier-domain interferometric detection. Although FF-SS-OCT implements high-speed volumetric imaging, it suffers from the cross-talk-generated noise from spatially coherent lasers. This noise reduces the transversal image resolution, which in turn, limits the wide adaptation of FF-SS-OCT for practical and clinical applications. Here, we introduce the novel spatiotemporal optical coherence (STOC) manipulation. In STOC the time-varying inhomogeneous phase masks are used to modulate the light incident on the sample. By properly adjusting these phase masks, the spatial coherence can be reduced. Consequently, the cross-talk-generated noise is suppressed, the transversal image resolution is improved by the factor of2 , and sample features become visible. STOC approach is validated by imaging 1951 USAF resolution test chart covered by the diffuser, scattering phantom and the rat skin ex vivo. In all these cases STOC suppresses the cross-talk-generated noise, and importantly, do not compromise the transversal resolution. Thus, our method provides an enhancement of FF-SS-OCT that can be beneficial for imaging biological samples.
Collapse
Affiliation(s)
- Dawid Borycki
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Michał Hamkało
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Maciej Nowakowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| | - Maciej Wojtkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun, Poland
| |
Collapse
|
5
|
Abstract
Ultraviolet (UV) spectroscopy is a powerful tool for quantitative (bio)chemical analysis, but its application to molecular imaging and microscopy has been limited. Here we introduce ultraviolet hyperspectral interferometric (UHI) microscopy, which leverages coherent detection of optical fields to overcome significant challenges associated with UV spectroscopy when applied to molecular imaging. We demonstrate that this method enables quantitative spectral analysis of important endogenous biomolecules with subcellular spatial resolution and sensitivity to nanometer-scaled structures for label-free molecular imaging of live cells.
Collapse
|
6
|
Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings. APPLIED SCIENCES-BASEL 2017. [DOI: 10.3390/app7040351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
7
|
Barrick J, Doblas A, Gardner MR, Sears PR, Ostrowski LE, Oldenburg AL. High-speed and high-sensitivity parallel spectral-domain optical coherence tomography using a supercontinuum light source. OPTICS LETTERS 2016; 41:5620-5623. [PMID: 27973473 PMCID: PMC5235345 DOI: 10.1364/ol.41.005620] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The three most important metrics in optical coherence tomography (OCT) are resolution, speed, and sensitivity. Because there is a complex interplay between these metrics, no previous work has obtained the best performance in all three metrics simultaneously. We demonstrate that a high-power supercontinuum source, in combination with parallel spectral-domain OCT, achieves an unparalleled combination of resolution, speed, and sensitivity. This system captures cross-sectional images spanning 4 mm×0.5 mm at 1,024,000 lines/s with 2×14 μm resolution (axial×transverse) at a sensitivity of 113 dB. Imaging using the proposed system is demonstrated on highly differentiated human bronchial epithelial cells to capture and spatially localize ciliary dynamics.
Collapse
|
8
|
McNamara PM, Dsouza R, O'Riordan C, Collins S, O'Brien P, Wilson C, Hogan J, Leahy MJ. Development of a first-generation miniature multiple reference optical coherence tomography imaging device. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:126020. [PMID: 28030742 DOI: 10.1117/1.jbo.21.12.126020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/07/2016] [Indexed: 05/15/2023]
Abstract
Multiple reference optical coherence tomography (MR-OCT) is a technology ideally suited to low-cost, compact OCT imaging. This modality is an extension of time-domain OCT with the addition of a partial mirror in front of the reference mirror. This enables extended, simultaneous depth scanning with the relatively short scan range of a miniature voice coil motor on which the scanning mirror is mounted. This work details early stage development of the first iteration of a miniature MR-OCT device. This iteration utilizes a fiber-coupled input from an off-board superluminescent diode. The dimensions of the module are 40 × 57 ?? mm . Off-the-shelf miniature optical components, voice coil motors, and photodetectors are used, with the complexity of design depending on the specific application. The photonic module can be configured as either polarized or nonpolarized and can include balanced detection. The results shown in this work are from the nonpolarized device. The system was characterized through measurement of the input spectrum, axial resolution, and signal-to-noise ratio. Typical B-scans of static and in vivo samples are shown, which illustrate the potential applications for such a technology.
Collapse
Affiliation(s)
- Paul M McNamara
- National University of Ireland, School of Physics, Tissue Optics and Microcirculation Imaging Group, National Biophotonics and Imaging Platform, Galway H91 CF50, IrelandbCompact Imaging Inc., 897 Independence Avenue, Suite 5B, Mountain View, California 94043, United States
| | - Roshan Dsouza
- National University of Ireland, School of Physics, Tissue Optics and Microcirculation Imaging Group, National Biophotonics and Imaging Platform, Galway H91 CF50, IrelandbCompact Imaging Inc., 897 Independence Avenue, Suite 5B, Mountain View, California 94043, United States
| | - Colm O'Riordan
- Irish Photonic Integration Centre (IPIC), Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12 R5CP, Ireland
| | - Seán Collins
- Irish Photonic Integration Centre (IPIC), Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12 R5CP, Ireland
| | - Peter O'Brien
- Irish Photonic Integration Centre (IPIC), Tyndall National Institute, Lee Maltings Complex, Dyke Parade, Cork T12 R5CP, Ireland
| | - Carol Wilson
- Compact Imaging Inc., 897 Independence Avenue, Suite 5B, Mountain View, California 94043, United States
| | - Josh Hogan
- Compact Imaging Inc., 897 Independence Avenue, Suite 5B, Mountain View, California 94043, United States
| | - Martin J Leahy
- National University of Ireland, School of Physics, Tissue Optics and Microcirculation Imaging Group, National Biophotonics and Imaging Platform, Galway H91 CF50, Ireland
| |
Collapse
|
9
|
Lawman S, Dong Y, Williams BM, Romano V, Kaye S, Harding SP, Willoughby C, Shen YC, Zheng Y. High resolution corneal and single pulse imaging with line field spectral domain optical coherence tomography. OPTICS EXPRESS 2016; 24:12395-405. [PMID: 27410154 DOI: 10.1364/oe.24.012395] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We report the development of a Spectral Domain Line Field Optical Coherence Tomography (LF-OCT) system, using a broad bandwidth and spatial coherent Super-Continuum (SC) source. With conventional quasi-Continuous Wave (CW) setup we achieve axial resolutions up to 2.1 μm in air and 3D volume imaging speeds up to 213 kA-Scan/s. Furthermore, we report the use of a single SC pulse, of 2 ns duration, to temporally gate an OCT B-Scan image of 70 A-Scans. This is the equivalent of 35 GA-Scans/s. We apply the CW setup for high resolution imaging of the fine structures of a human cornea sample ex-vivo. The single pulse setup is applied to imaging of a coated pharmaceutical tablet. The fixed pattern noise due to spectral noise is removed by subtracting the median magnitude A-Scan. We also demonstrate that the Fourier phase can be used to remove aberration caused artefacts.
Collapse
|
10
|
Brown WJ, Kim S, Wax A. Noise characterization of supercontinuum sources for low-coherence interferometry applications. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:2703-10. [PMID: 25606759 PMCID: PMC4457326 DOI: 10.1364/josaa.31.002703] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We examine the noise properties of supercontinuum light sources when used in low-coherence interferometry applications. The first application is a multiple-scattering low-coherence interferometry (ms2/LCI) system, where high power and long image acquisition times are required to image deep into tissue. For this system, we compare the noise characteristics of two supercontinuum sources from different suppliers. Both sources have long-term drift that limits the amount of time over which signal averaging is advantageous for reducing noise. The second application is a high-resolution optical coherence tomography system, where broadband light is needed for high axial resolution. For this system, we compare the noise performance of the two supercontinuum sources and a light source based on four superluminescent diodes (SLD) using imaging contrast as a comparative metric. We find that the NKT SuperK has superior noise performance compared with the Fianium SC-450-4, but neither meets the performance of the SLD.
Collapse
Affiliation(s)
- William J. Brown
- Department of Biomedical Engineering and Fitzpatrick Center for Photonics, Duke University, Durham, North Carolina 27708, USA
| | - Sanghoon Kim
- Department of Biomedical Engineering and Fitzpatrick Center for Photonics, Duke University, Durham, North Carolina 27708, USA
| | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Center for Photonics, Duke University, Durham, North Carolina 27708, USA
- Corresponding author:
| |
Collapse
|
11
|
Lee HY, Marvdashti T, Duan L, Khan SA, Ellerbee AK. Scalable multiplexing for parallel imaging with interleaved optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2014; 5:3192-203. [PMID: 25401031 PMCID: PMC4230859 DOI: 10.1364/boe.5.003192] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 05/28/2023]
Abstract
We demonstrate highly parallel imaging with interleaved optical coherence tomography (iOCT) using an in-house-fabricated, air-spaced virtually-imaged phased array (VIPA). The air-spaced VIPA performs spectral encoding of the interferograms from multiple lateral points within a single sweep of the source and allows us to tune and balance several imaging parameters: number of multiplexed points, ranging depth, and sensitivity. In addition to a thorough discussion of the parameters and operating principles of the VIPA, we experimentally demonstrate the effect of different VIPA designs on the multiplexing potential of iOCT. Using a 200-kHz light source, we achieve an effective A-scan rate of 3.2-MHz by multiplexing 16 lateral points onto a single wavelength sweep. The improved sensitivity of this system is demonstrated for 3D imaging of biological samples such as a human finger and a fruit fly.
Collapse
|
12
|
Rinehart MT, Jaedicke V, Wax A. Quantitative phase microscopy with off-axis optical coherence tomography. OPTICS LETTERS 2014; 39:1996-9. [PMID: 24686658 DOI: 10.1364/ol.39.001996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We have developed a modality for quantitative phase imaging within spectral domain optical coherence tomography based on using an off-axis reference beam. By tilting the propagation of the reference beam relative to that of the sample beam, a spatially varying fringe is generated. Upon detection of this fringe using a parallel spectral domain scheme, the fringe can be used to separate the interference component of the signal and obtain the complex sample field. In addition to providing quantitative phase measurements within a depth resolved measurement, this approach also allows elimination of the complex conjugate artifact, a known limitation of spectral interferometry. The principle of the approach is described here along with demonstration of its capabilities using technical samples.
Collapse
|
13
|
Lee HY, Sudkamp H, Marvdashti T, Ellerbee AK. Interleaved optical coherence tomography. OPTICS EXPRESS 2013; 21:26542-56. [PMID: 24216876 DOI: 10.1364/oe.21.026542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present a novel and cost-effective technique--interleaved optical coherence tomography (iOCT)--to enhance the imaging speed of swept source OCT systems by acquiring data from multiple lateral positions simultaneously during a single wavelength sweep, using a single detector and a virtually imaged phase array (VIPA) as a multi-band demultiplexer. This technique uses spectral encoding to convert coherence length into higher imaging speed; the speed enhancement factor is independent of the source speed or center wavelength, and the effective A-scan rate scales linearly with sweep speed. The optical configuration requires only a change in the sample arm of a traditional OCT system and preserves the axial resolution and fall-off characteristic of a traditional SS-OCT using the same light source. Using 10 kHz, 20 kHz and 100 kHz sources we provide a first demonstration of image speed enhancement factors of up to 12, 6 and 10, respectively, which yield effective A-scan rates of 120 kHz, 120 kHz and 1 MHz for B-scan imaging, with a sensitivity of up to 82.5 dB. We also show that iOCT can image faster dynamics than traditional OCT B-scan imaging and is capable of 3D biological imaging. The iOCT concept suggests a new route to high-speed OCT imaging for laser developers: that is, by focusing on improving the coherence length and linewidth of existing and emerging sources. Hence, iOCT is a nice complement to ongoing research and commercial efforts to enable faster imaging through development of lasers with faster sweep rates, and offers new hope for existing sources with slow sweep rates and potential for enhancement of coherence length to compete with faster sources to achieve high-speed OCT.
Collapse
|
14
|
Li YL, Seekell K, Yuan H, Robles FE, Wax A. Multispectral nanoparticle contrast agents for true-color spectroscopic optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2012; 3:1914-23. [PMID: 22876354 PMCID: PMC3409709 DOI: 10.1364/boe.3.001914] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/18/2012] [Accepted: 07/18/2012] [Indexed: 05/18/2023]
Abstract
We have recently developed a novel dual window scheme for processing spectroscopic OCT images to provide spatially resolved true color imaging of chromophores in scattering samples. Here we apply this method to measure the extinction spectra of plasmonic nanoparticles at various concentrations for potential in vivo applications. We experimentally demonstrate sub-nanomolar sensitivity in the measurement of nanoparticle concentrations, and show that colorimetric imaging with multiple species of nanoparticles produces enhanced contrast for spectroscopic OCT in both tissue phantom and cell studies.
Collapse
Affiliation(s)
- You Leo Li
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | - Kevin Seekell
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | - Hsiangkuo Yuan
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| | | | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham NC 27708, USA
| |
Collapse
|
15
|
Abstract
Nonlinear phase dispersion spectroscopy is introduced as a means to retrieve wideband, high spectral resolution profiles of the wavelength-dependent real part of the refractive index. The method is based on detecting dispersion effects imparted to a light field with low coherence transmitted through a thin sample and detected interferometrically in the spectral domain. The same sampled signal is also processed to yield quantitative phase maps and spectral information regarding the total attenuation coefficient using spectral-domain phase microscopy and spectroscopic optical coherence tomography (SOCT), respectively. Proof-of-concept experiments using fluorescent and nonfluorescent polystyrene beads and another using a red blood cell demonstrate the ability of the method to quantify various absorptive/dispersive features. The increased sensitivity of this method, novel to our knowledge, is compared to intensity-based spectroscopy (e.g., SOCT), and potential applications are discussed.
Collapse
Affiliation(s)
- Francisco E Robles
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA.
| | | | | |
Collapse
|
16
|
Robles FE, Wilson C, Grant G, Wax A. Molecular imaging true-colour spectroscopic optical coherence tomography. NATURE PHOTONICS 2011; 5:744-747. [PMID: 23144652 PMCID: PMC3491993 DOI: 10.1038/nphoton.2011.257] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Molecular imaging holds a pivotal role in medicine due to its ability to provide invaluable insight into disease mechanisms at molecular and cellular levels. To this end, various techniques have been developed for molecular imaging, each with its own advantages and disadvantages(1-4). For example, fluorescence imaging achieves micrometre-scale resolution, but has low penetration depths and is mostly limited to exogenous agents. Here, we demonstrate molecular imaging of endogenous and exogenous chromophores using a novel form of spectroscopic optical coherence tomography. Our approach consists of using a wide spectral bandwidth laser source centred in the visible spectrum, thereby allowing facile assessment of haemoglobin oxygen levels, providing contrast from readily available absorbers, and enabling true-colour representation of samples. This approach provides high spectral fidelity while imaging at the micrometre scale in three dimensions. Molecular imaging true-colour spectroscopic optical coherence tomography (METRiCS OCT) has significant implications for many biomedical applications including ophthalmology, early cancer detection, and understanding fundamental disease mechanisms such as hypoxia and angiogenesis.
Collapse
Affiliation(s)
- Francisco E. Robles
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, USA
- Medical Physics Program, Duke University, Durham, North Carolina 27708, USA
| | - Christy Wilson
- Pediatric Neurosurgery, Duke University, Durham, North Carolina 27708, USA
| | - Gerald Grant
- Pediatric Neurosurgery, Duke University, Durham, North Carolina 27708, USA
| | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, USA
- Medical Physics Program, Duke University, Durham, North Carolina 27708, USA
- Correspondence and requests for materials should be addressed to A.W.
| |
Collapse
|
17
|
Giacomelli MG, Wax A. Imaging beyond the ballistic limit in coherence imaging using multiply scattered light. OPTICS EXPRESS 2011; 19:4268-79. [PMID: 21369257 PMCID: PMC3368313 DOI: 10.1364/oe.19.004268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We present an imaging system based on low coherence interferometric detection of multiply scattered light for extended depth imaging into highly scattering media. By incorporating angle-resolved detection, coherence imaging with multiply scattered photons is shown to be both feasible and potentially superior to existing techniques for performing time-resolved measurements of scattered light. Imaging is demonstrated through nearly 100 mean free paths of scattering phantom in a single-ended geometry. The resolution and imaging contrast are compared to those obtained with conventional OCT systems which chiefly detect singly scattered light.
Collapse
Affiliation(s)
- Michael G. Giacomelli
- Department of Biomedical Engineering and Fitzpatrick Center for Photonics, Duke University, Durham, North Carolina 27708,
USA
| | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Center for Photonics, Duke University, Durham, North Carolina 27708,
USA
| |
Collapse
|
18
|
Robles FE, Zhu Y, Lee J, Sharma S, Wax A. Detection of early colorectal cancer development in the azoxymethane rat carcinogenesis model with Fourier domain low coherence interferometry. BIOMEDICAL OPTICS EXPRESS 2010; 1:736-745. [PMID: 21258505 PMCID: PMC3017982 DOI: 10.1364/boe.1.000736] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 08/16/2010] [Accepted: 08/20/2010] [Indexed: 05/03/2023]
Abstract
Fourier domain low coherence interferometry (fLCI) is an emerging optical technique used to quantitatively assess cell nuclear morphology in tissue as a means of detecting early cancer development. In this work, we use the azoxymethane rat carcinogenesis model, a well characterized and established model for colon cancer research, to demonstrate the ability of fLCI to distinguish between normal and preneoplastic ex-vivo colon tissue. The results show highly statistically significant differences between the measured cell nuclear diameters of normal and azoxymethane-treated tissues, thus providing strong evidence that fLCI may be a powerful tool for non-invasive, quantitative detection of early changes associated with colorectal cancer development.
Collapse
Affiliation(s)
- Francisco E. Robles
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics,
Duke University, Durham NC 27708, USA
- Medical Physics Program, Duke University, Durham NC 27708, USA
| | - Yizheng Zhu
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics,
Duke University, Durham NC 27708, USA
| | - Jin Lee
- The Hamner Institutes for Health, Research Triangle Park, NC 27709, USA
| | - Sheela Sharma
- The Hamner Institutes for Health, Research Triangle Park, NC 27709, USA
| | - Adam Wax
- Department of Biomedical Engineering and Fitzpatrick Institute for Photonics,
Duke University, Durham NC 27708, USA
- Medical Physics Program, Duke University, Durham NC 27708, USA
| |
Collapse
|
19
|
Robles FE, Chowdhury S, Wax A. Assessing hemoglobin concentration using spectroscopic optical coherence tomography for feasibility of tissue diagnostics. BIOMEDICAL OPTICS EXPRESS 2010; 1:310-317. [PMID: 21258468 DOI: 10.1364/boe.1.000310] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 07/16/2010] [Accepted: 07/16/2010] [Indexed: 05/18/2023]
Abstract
Hemoglobin (Hb) concentration and oxygen saturation levels are important biomarkers for various diseases, including cancer. Here, we investigate the ability to measure these parameters for tissue using spectroscopic optical coherence tomography (SOCT). A parallel frequency domain OCT system is used with detection spanning the visible region of the spectrum (450 nm to 700 nm). Oxygenated and deoxygenated Hb absorbing phantoms are analyzed. The results show that Hb concentrations as low as 1.2 g/L at 1 mm can be retrieved indicating that both normal and cancerous tissue measurements may be obtained. However, measurement of oxygen saturation levels may not be achieved with this approach.
Collapse
|
20
|
Robles FE, Wax A. Measuring morphological features using light-scattering spectroscopy and Fourier-domain low-coherence interferometry. OPTICS LETTERS 2010; 35:360-2. [PMID: 20125721 PMCID: PMC2831473 DOI: 10.1364/ol.35.000360] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We present measurements of morphological features in a thick turbid sample using light-scattering spectroscopy (LSS) and Fourier-domain low-coherence interferometry (fLCI) by processing with the dual-window (DW) method. A parallel frequency domain optical coherence tomography (OCT) system with a white-light source is used to image a two-layer phantom containing polystyrene beads of diameters 4.00 and 6.98 mum on the top and bottom layers, respectively. The DW method decomposes each OCT A-scan into a time-frequency distribution with simultaneously high spectral and spatial resolution. The spectral information from localized regions in the sample is used to determine scatterer structure. The results show that the two scatterer populations can be differentiated using LSS and fLCI.
Collapse
|
21
|
Graf RN, Robles FE, Chen X, Wax A. Detecting precancerous lesions in the hamster cheek pouch using spectroscopic white-light optical coherence tomography to assess nuclear morphology via spectral oscillations. JOURNAL OF BIOMEDICAL OPTICS 2009; 14:064030. [PMID: 20059268 PMCID: PMC2803719 DOI: 10.1117/1.3269680] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 10/08/2009] [Accepted: 10/09/2009] [Indexed: 05/19/2023]
Abstract
We have developed a novel dual-window approach for spectroscopic optical coherence tomography (OCT) measurements and applied it to probe nuclear morphology in tissue samples drawn from the hamster cheek pouch carcinogenesis model. The dual-window approach enables high spectral and depth resolution simultaneously, allowing detection of spectral oscillations, which we isolate to determine the structure of cell nuclei in the basal layer of the epithelium. The measurements were executed with our parallel frequency domain OCT system, which uses light from a thermal source, providing high bandwidth and access to the visible portion of the spectrum. The structural measurements show a highly statistically significant difference between untreated (normal) and treated (hyperplastic/dysplastic) tissues, indicating the potential utility of this approach as a diagnostic method.
Collapse
Affiliation(s)
- Robert N Graf
- Duke University, Department of Biomedical Engineering, 136 Hudson Hall, Durham, North Carolina 27708, USA
| | | | | | | |
Collapse
|
22
|
Liu J, Xu Z, Kim YL. Virtual pinhole-scanning spectroscopic imaging platform using low-coherence enhanced backscattering. OPTICS LETTERS 2009; 34:2387-2389. [PMID: 19684791 DOI: 10.1364/ol.34.002387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present that multiple mutually independent coherence areas can be used for simultaneous spatial filtering in an imaging platform as effective as pinhole scanning. In this imaging platform, the unique combination of low-spatial-coherence illumination and differential angle imaging allows us to take advantage of low-coherence enhanced-backscattering (LEBS) phenomenon to permit self-generated optical sectioning to the subsurface in a relatively large area. We further demonstrate that LEBS spectroscopic imaging substantially minimizes cross talk among adjacent pixels, rejects the background light caused by out-of-plane scattered light, and thereby enhances image contrast and resolution.
Collapse
Affiliation(s)
- Jingjing Liu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | | | | |
Collapse
|
23
|
Robles F, Graf RN, Wax A. Dual window method for processing spectroscopic optical coherence tomography signals with simultaneously high spectral and temporal resolution. OPTICS EXPRESS 2009; 17:6799-812. [PMID: 19365509 PMCID: PMC2834290 DOI: 10.1364/oe.17.006799] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Current methods for analysis of spectroscopic optical coherence tomography (SOCT) signals suffer from an inherent tradeoff between time (depth) and frequency (wavelength) resolution. Here, we present a dual window (DW) method for reconstructing time frequency distributions (TFDs) that applies two orthogonal Gaussian windows that independently determine the spectral and temporal resolution. The effectiveness of the method is demonstrated in simulations and in processing of measured OCT signals that contain fields which vary in time and frequency. The DW method yields TFDs that maintain high spectral and temporal resolution and are free from the artifacts and limitations commonly observed with other processing methods.
Collapse
Affiliation(s)
- Francisco Robles
- Department of Medical Physics, Duke University, Durham, NC 27708
- Department of Biomedical Engineering and the Fitzpatrick Institute for Photonics Duke University, Durham, NC 27708
| | - Robert N. Graf
- Department of Biomedical Engineering and the Fitzpatrick Institute for Photonics Duke University, Durham, NC 27708
| | - Adam Wax
- Department of Biomedical Engineering and the Fitzpatrick Institute for Photonics Duke University, Durham, NC 27708
| |
Collapse
|