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d'Errico F, Di Fulvio A. Advanced readout methods for superheated emulsion detectors. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:053304. [PMID: 29864841 DOI: 10.1063/1.5017756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Superheated emulsions develop visible vapor bubbles when exposed to ionizing radiation. They consist in droplets of a metastable liquid, emulsified in an inert matrix. The formation of a bubble cavity is accompanied by sound waves. Evaporated bubbles also exhibit a lower refractive index, compared to the inert gel matrix. These two physical phenomena have been exploited to count the number of evaporated bubbles and thus measure the interacting radiation flux. Systems based on piezoelectric transducers have been traditionally used to acquire the acoustic (pressure) signals generated by bubble evaporation. Such systems can operate at ambient noise levels exceeding 100 dB; however, they are affected by a significant dead time (>10 ms). An optical readout technique relying on the scattering of light by neutron-induced bubbles has been recently improved in order to minimize measurement dead time and ambient noise sensitivity. Beams of infra-red light from light-emitting diode (LED) sources cross the active area of the detector and are deflected by evaporated bubbles. The scattered light correlates with bubble density. Planar photodiodes are affixed along the detector length in optimized positions, allowing the detection of scattered light from the bubbles and minimizing the detection of direct light from the LEDs. A low-noise signal-conditioning stage has been designed and realized to amplify the current induced in the photodiodes by scattered light and to subtract the background signal due to intrinsic scattering within the detector matrix. The proposed amplification architecture maximizes the measurement signal-to-noise ratio, yielding a readout uncertainty of 6% (±1 SD), with 1000 evaporated bubbles in a detector active volume of 150 ml (6 cm detector diameter). In this work, we prove that the intensity of scattered light also relates to the bubble size, which can be controlled by applying an external pressure to the detector emulsion. This effect can be exploited during the readout procedure to minimize shadowing effects between bubbles, which become severe when the latter are several thousands. The detector we used in this work is based on superheated C-318 (octafluorocyclobutane), emulsified in 100 μm ± 10% (1 SD) diameter drops in an inert matrix of approximately 150 ml. The detector was operated at room temperature and ambient pressure.
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Affiliation(s)
- F d'Errico
- Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06511, USA
| | - A Di Fulvio
- Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06511, USA
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2
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Bhowmik T, Liu H, Ye Z, Oraintara S. Dimensionality Reduction Based Optimization Algorithm for Sparse 3-D Image Reconstruction in Diffuse Optical Tomography. Sci Rep 2016; 6:22242. [PMID: 26940661 PMCID: PMC4778023 DOI: 10.1038/srep22242] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 02/10/2016] [Indexed: 11/13/2022] Open
Abstract
Diffuse optical tomography (DOT) is a relatively low cost and portable imaging modality for reconstruction of optical properties in a highly scattering medium, such as human tissue. The inverse problem in DOT is highly ill-posed, making reconstruction of high-quality image a critical challenge. Because of the nature of sparsity in DOT, sparsity regularization has been utilized to achieve high-quality DOT reconstruction. However, conventional approaches using sparse optimization are computationally expensive and have no selection criteria to optimize the regularization parameter. In this paper, a novel algorithm, Dimensionality Reduction based Optimization for DOT (DRO-DOT), is proposed. It reduces the dimensionality of the inverse DOT problem by reducing the number of unknowns in two steps and thereby makes the overall process fast. First, it constructs a low resolution voxel basis based on the sensing-matrix properties to find an image support. Second, it reconstructs the sparse image inside this support. To compensate for the reduced sensitivity with increasing depth, depth compensation is incorporated in DRO-DOT. An efficient method to optimally select the regularization parameter is proposed for obtaining a high-quality DOT image. DRO-DOT is also able to reconstruct high-resolution images even with a limited number of optodes in a spatially limited imaging set-up.
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Affiliation(s)
- Tanmoy Bhowmik
- Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Zhou Ye
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Soontorn Oraintara
- Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX 76019, USA.,Department of Biomedical Engineering, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
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3
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Naser MA, Deen MJ. Time-domain diffuse optical tomography using recursive direct method of calculating Jacobian at selected temporal points. Biomed Phys Eng Express 2015. [DOI: 10.1088/2057-1976/1/4/045207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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4
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Grabtchak S, Montgomery LG, Pang B, Wang Y, Zhang C, Li Z, Xia Y, Whelan WM. Interstitial diffuse radiance spectroscopy of gold nanocages and nanorods in bulk muscle tissues. Int J Nanomedicine 2015; 10:1307-20. [PMID: 25709450 PMCID: PMC4335609 DOI: 10.2147/ijn.s79246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Radiance spectroscopy was applied to the interstitial detection of localized inclusions containing Au nanocages or nanorods with various concentrations embedded in porcine muscle phantoms. The radiance was quantified using a perturbation approach, which enabled the separation of contributions from the porcine phantom and the localized inclusion, with the inclusion serving as a perturbation probe of photon distributions in the turbid medium. Positioning the inclusion at various places in the phantom allowed for tracking of photons that originated from a light source, passed through the inclusion's location, and reached a detector. The inclusions with high extinction coefficients were able to absorb nearly all photons in the range of 650-900 nm, leading to a spectrally flat radiance signal. This signal could be converted to the relative density of photons incident on the inclusion. Finally, the experimentally measured quantities were expressed via the relative perturbation and arranged into the classical Beer-Lambert law that allowed one to extract the extinction coefficients of various types of Au nanoparticles in both the transmission and back reflection geometries. It was shown that the spatial variation of perturbation could be described as 1/r dependence, where r is the distance between the inclusion and the detector. Due to a larger absorption cross section, Au nanocages produced greater perturbations than Au nanorods of equal particle concentration, indicating a better suitability of Au nanocages as contrast agents for optical measurements in turbid media. Individual measurements from different inclusions were combined into detectability maps.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, Canada
| | - Logan G Montgomery
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
| | - Bo Pang
- Department of Biomedical Engineering, Peking University, Beijing, People’s Republic of China
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Yi Wang
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Key Laboratory of Green Synthesis and Applications, College of Chemistry, Chongqing Normal University, Chongqing, People’s Republic of China
| | - Chao Zhang
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Physics and Optoelectronics, South China University of Technology, Guangzhou, People’s Republic of China
| | - Zhiyuan Li
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Physics and Optoelectronics, South China University of Technology, Guangzhou, People’s Republic of China
| | - Younan Xia
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- School of Chemistry and Biochemistry, and School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - William M Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Atlantic Veterinary College, Charlottetown, PEI, Canada
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5
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Cybulski TR, Glaser JI, Marblestone AH, Zamft BM, Boyden ES, Church GM, Kording KP. Spatial information in large-scale neural recordings. Front Comput Neurosci 2015; 8:172. [PMID: 25653613 PMCID: PMC4301009 DOI: 10.3389/fncom.2014.00172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 12/12/2014] [Indexed: 11/16/2022] Open
Abstract
To record from a given neuron, a recording technology must be able to separate the activity of that neuron from the activity of its neighbors. Here, we develop a Fisher information based framework to determine the conditions under which this is feasible for a given technology. This framework combines measurable point spread functions with measurable noise distributions to produce theoretical bounds on the precision with which a recording technology can localize neural activities. If there is sufficient information to uniquely localize neural activities, then a technology will, from an information theoretic perspective, be able to record from these neurons. We (1) describe this framework, and (2) demonstrate its application in model experiments. This method generalizes to many recording devices that resolve objects in space and should be useful in the design of next-generation scalable neural recording systems.
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Affiliation(s)
- Thaddeus R. Cybulski
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern UniversityChicago, IL, USA
| | - Joshua I. Glaser
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern UniversityChicago, IL, USA
| | - Adam H. Marblestone
- Biophysics Program, Harvard UniversityBoston, MA, USA
- Wyss Institute, Harvard UniversityBoston, MA, USA
| | - Bradley M. Zamft
- Department of Genetics, Harvard Medical School, Harvard UniversityBoston, MA, USA
| | - Edward S. Boyden
- Media Lab, Massachusetts Institute of TechnologyCambridge, MA, USA
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridge, MA, USA
- McGovern Institute, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - George M. Church
- Biophysics Program, Harvard UniversityBoston, MA, USA
- Wyss Institute, Harvard UniversityBoston, MA, USA
- Department of Genetics, Harvard Medical School, Harvard UniversityBoston, MA, USA
| | - Konrad P. Kording
- Department of Physical Medicine and Rehabilitation, Rehabilitation Institute of Chicago, Northwestern UniversityChicago, IL, USA
- Department of Physiology, Northwestern UniversityChicago, IL, USA
- Department of Applied Mathematics, Northwestern UniversityChicago, IL, USA
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6
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Hu X, Deng Y, Lin X, Suo J, Dai Q, Barsi C, Raskar R. Robust and accurate transient light transport decomposition via convolutional sparse coding. OPTICS LETTERS 2014; 39:3177-3180. [PMID: 24876006 DOI: 10.1364/ol.39.003177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ultrafast sources and detectors have been used to record the time-resolved scattering of light propagating through macroscopic scenes. In the context of computational imaging, decomposition of this transient light transport (TLT) is useful for applications, such as characterizing materials, imaging through diffuser layers, and relighting scenes dynamically. Here, we demonstrate a method of convolutional sparse coding to decompose TLT into direct reflections, inter-reflections, and subsurface scattering. The method relies on the sparsity composition of the time-resolved kernel. We show that it is robust and accurate to noise during the acquisition process.
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Carbone NA, Baez GR, García HA, Waks Serra MV, Di Rocco HO, Iriarte DI, Pomarico JA, Grosenick D, Macdonald R. Diffuse reflectance optical topography: location of inclusions in 3D and detectability limits. BIOMEDICAL OPTICS EXPRESS 2014; 5:1336-1354. [PMID: 24876999 PMCID: PMC4026887 DOI: 10.1364/boe.5.001336] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 02/06/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
In the present contribution we investigate the images of CW diffusely reflected light for a point-like source, registered by a CCD camera imaging a turbid medium containing an absorbing lesion. We show that detection of μa variations (absorption anomalies) is achieved if images are normalized to background intensity. A theoretical analysis based on the diffusion approximation is presented to investigate the sensitivity and the limitations of our proposal and a novel procedure to find the location of the inclusions in 3D is given and tested. An analysis of the noise and its influence on the detection capabilities of our proposal is provided. Experimental results on phantoms are also given, supporting the proposed approach.
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Affiliation(s)
- N. A. Carbone
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - G. R. Baez
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - H. A. García
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - M. V. Waks Serra
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - H. O. Di Rocco
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - D. I. Iriarte
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - J. A. Pomarico
- IFAS, CIFICEN (CONICET - UNCPBA) - Pinto 399- B7000GHG Tandil
Argentina
| | - D. Grosenick
- PHYSIKALISCH-TECHNISCHE BUNDESANSTALT (PTB), Abbestr. 2-12, 10587 Berlin -
Germany
| | - R. Macdonald
- PHYSIKALISCH-TECHNISCHE BUNDESANSTALT (PTB), Abbestr. 2-12, 10587 Berlin -
Germany
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8
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Naik N, Barsi C, Velten A, Raskar R. Estimating wide-angle, spatially varying reflectance using time-resolved inversion of backscattered light. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2014; 31:957-963. [PMID: 24979627 DOI: 10.1364/josaa.31.000957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Imaging through complex media is a well-known challenge, as scattering distorts a signal and invalidates imaging equations. For coherent imaging, the input field can be reconstructed using phase conjugation or knowledge of the complex transmission matrix. However, for incoherent light, wave interference methods are limited to small viewing angles. On the other hand, time-resolved methods do not rely on signal or object phase correlations, making them suitable for reconstructing wide-angle, larger-scale objects. Previously, a time-resolved technique was demonstrated for uniformly reflecting objects. Here, we generalize the technique to reconstruct the spatially varying reflectance of shapes hidden by angle-dependent diffuse layers. The technique is a noninvasive method of imaging three-dimensional objects without relying on coherence. For a given diffuser, ultrafast measurements are used in a convex optimization program to reconstruct a wide-angle, three-dimensional reflectance function. The method has potential use for biological imaging and material characterization.
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9
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Grabtchak S, Callaghan KB, Whelan WM. Tagging photons with gold nanoparticles as localized absorbers in optical measurements in turbid media. BIOMEDICAL OPTICS EXPRESS 2013; 4:2989-3006. [PMID: 24409396 PMCID: PMC3862156 DOI: 10.1364/boe.4.002989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 06/03/2023]
Abstract
We analyze a role of a localized inclusion as a probe for spatial distributions of migrating photons in turbid media. We present new experimental data and two-dimensional analysis of radiance detection of a localized absorptive inclusion formed by gold nanoparticles in Intralipid-1% when the target is translated along the line connecting the light source and detector. Data are analyzed using the novel analytical expression for the relative angular photon distribution function for radiance developed by extending the perturbation approach for fluence. Obtained photon maps allow predicting conditions for detectability of inclusions for which proximity to the detector is essential.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, NS B3H3J5, Canada
| | - Kristen B. Callaghan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
| | - William M. Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Atlantic Veterinary College, Charlottetown, PEI C1A4P3, Canada
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10
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Grabtchak S, Palmer TJ, Vitkin IA, Whelan WM. Radiance detection of non-scattering inclusions in turbid media. BIOMEDICAL OPTICS EXPRESS 2012; 3:3001-11. [PMID: 23162735 PMCID: PMC3493233 DOI: 10.1364/boe.3.003001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 10/24/2012] [Accepted: 10/25/2012] [Indexed: 05/10/2023]
Abstract
Detection of non-scattering domains (voids) is an area of active research in biomedical optics. To avoid complexities of image reconstruction algorithms and requirements of a priori knowledge of void locations inherent to diffuse optical tomography (DOT), it would be useful to establish specific experimental signatures of voids that would help identify and detect them by other means. To address this, we present a radiance-based spectro-angular mapping approach that identifies void locations in the angular domain and establishes their spectral features. Using water-filled capillaries in scattering Intralipid as a test platform, we demonstrate perturbations in the directional photon density distribution produced by individual voids.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, NS, Canada
| | - Tyler J. Palmer
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
| | - I. Alex Vitkin
- Departments of Medical Biophysics and Radiation Oncology, University of Toronto and Ontario Cancer Institute/University Health Network, Toronto, ON, Canada
| | - William M. Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Atlantic Veterinary College, Charlottetown, PEI, Canada
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11
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Chuang CC, Lee CY, Chen CM, Hsieh YS, Liu TC, Sun CW. Diffuser-aided diffuse optical imaging for breast tumor: a feasibility study based on time-resolved three-dimensional Monte Carlo modeling. IEEE Trans Biomed Eng 2012; 59:1454-61. [PMID: 22394571 DOI: 10.1109/tbme.2012.2187900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This study proposed diffuser-aided diffuse optical imaging (DADOI) as a new approach to improve the performance of the conventional diffuse optical tomography (DOT) approach for breast imaging. The 3-D breast model for Monte Carlo simulation is remodeled from clinical MRI image. The modified Beer-Lambert's law is adopted with the DADOI approach to substitute the complex algorithms of inverse problem for mapping of spatial distribution, and the depth information is obtained based on the time-of-flight estimation. The simulation results demonstrate that the time-resolved Monte Carlo method can be capable of performing source-detector separations analysis. The dynamics of photon migration with various source-detector separations are analyzed for the characterization of breast tissue and estimation of optode arrangement. The source-detector separations should be less than 4 cm for breast imaging in DOT system. Meanwhile, the feasibility of DADOI was manifested in this study. In the results, DADOI approach can provide better imaging contrast and faster imaging than conventional DOT measurement. The DADOI approach possesses great potential to detect the breast tumor in early stage and chemotherapy monitoring that implies a good feasibility for clinical application.
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Affiliation(s)
- Ching-Cheng Chuang
- Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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12
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Nouizi F, Torregrossa M, Chabrier R, Poulet P. Improvement of absorption and scattering discrimination by selection of sensitive points on temporal profile in diffuse optical tomography. OPTICS EXPRESS 2011; 19:12843-54. [PMID: 21716527 DOI: 10.1364/oe.19.012843] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We present a new method allowing the reconstruction of 3D time-domain diffuse optical tomography images, based on the time-dependent diffusion equation and an iterative algorithm (ART) using specific points on the temporal profiles. The first advantage of our method versus the full time-resolved scheme consists in considerably reducing the inverse problem resolution time. Secondly, in the presence of scattering heterogeneities, our method provides images of better quality comparatively to classical methods using full-time data or the first moments of the profiles.
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Affiliation(s)
- Farouk Nouizi
- Laboratoire d’Imagerie et de Neurosciences Cognitives, UMR 7237, Université de Strasbourg/CNRS, 4 rue Kirschleger, 67085 Strasbourg Cedex, France.
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13
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Maslennikova AV, Orlova AG, Golubiatnikov GY, Kamensky VA, Shakhova NM, Babaev AA, Snopova LB, Ivanova IP, Plekhanov VI, Prianikova TI, Turchin IV. Comparative study of tumor hypoxia by diffuse optical spectroscopy and immunohistochemistry in two tumor models. JOURNAL OF BIOPHOTONICS 2010; 3:743-51. [PMID: 20715133 DOI: 10.1002/jbio.201000060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The capabilities of diffuse optical spectroscopy for noninvasive assessing of oxygen status in experimental tumors have been demonstrated. Specific features of the distribution of total hemoglobin, oxygenated hemoglobin, deoxygenated hemoglobin, and blood-oxygen saturation were shown on two tumor models having different histological structure and functional characteristics. The results obtained by the optical technique were verified by immunohistochemical study of tissue samples marked with exogenous marker of hypoxia--pimonidazole.
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Affiliation(s)
- Anna V Maslennikova
- Institute of Applied Physics RAS, 46 Ulyanov Str., Nizhny Novgorod, Russia; Nizhny Novgorod State Medical Academy, 10/1 Minin Sqr., Nizhny Novgorod, Russia.
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14
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Soloviev VY, D'Andrea C, Mohan PS, Valentini G, Cubeddu R, Arridge SR. Fluorescence lifetime optical tomography with Discontinuous Galerkin discretisation scheme. BIOMEDICAL OPTICS EXPRESS 2010; 1:998-1013. [PMID: 21258525 PMCID: PMC3018046 DOI: 10.1364/boe.1.000998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 09/07/2010] [Accepted: 09/12/2010] [Indexed: 05/23/2023]
Abstract
We develop discontinuous Galerkin framework for solving direct and inverse problems in fluorescence diffusion optical tomography in turbid media. We show the advantages and the disadvantages of this method by comparing it with previously developed framework based on the finite volume discretization. The reconstruction algorithm was used with time-gated experimental dataset acquired by imaging a highly scattering cylindrical phantom concealing small fluorescent tubes. Optical parameters, quantum yield and lifetime were simultaneously reconstructed. Reconstruction results are presented and discussed.
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Affiliation(s)
- Vadim Y. Soloviev
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Cosimo D'Andrea
- Centre for Nano Science and Technology of Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - P. Surya Mohan
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
| | - Gianluca Valentini
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Rinaldo Cubeddu
- Istituto di Fotonica e Nanotecnologie (IFN-CNR), Italian Institute of Technology (IIT), Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Simon R. Arridge
- Departments of Computer Science, University College London, Gower Street, London WC1E 6BT, UK
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Durduran T, Choe R, Baker WB, Yodh AG. Diffuse Optics for Tissue Monitoring and Tomography. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2010; 73:076701. [PMID: 26120204 PMCID: PMC4482362 DOI: 10.1088/0034-4885/73/7/076701] [Citation(s) in RCA: 558] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This review describes the diffusion model for light transport in tissues and the medical applications of diffuse light. Diffuse optics is particularly useful for measurement of tissue hemodynamics, wherein quantitative assessment of oxy- and deoxy-hemoglobin concentrations and blood flow are desired. The theoretical basis for near-infrared or diffuse optical spectroscopy (NIRS or DOS, respectively) is developed, and the basic elements of diffuse optical tomography (DOT) are outlined. We also discuss diffuse correlation spectroscopy (DCS), a technique whereby temporal correlation functions of diffusing light are transported through tissue and are used to measure blood flow. Essential instrumentation is described, and representative brain and breast functional imaging and monitoring results illustrate the workings of these new tissue diagnostics.
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Affiliation(s)
- T Durduran
- ICFO- Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain
| | - R Choe
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - W B Baker
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - A G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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16
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Vasefi F, Ng E, Kaminska B, Chapman GH, Jordan K, Carson JJL. Transmission and fluorescence angular domain optical projection tomography of turbid media. APPLIED OPTICS 2009; 48:6448-6457. [PMID: 19935964 DOI: 10.1364/ao.48.006448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
When imaging through turbid media, objects are often blurred by scattered light. An optical collimator (i.e., an angular filter array) improves images by accepting only photons propagating within a narrow solid angle about the direction of the incident light. These photons are expected to participate in a limited number of small-angle scattering events, maintaining their original propagation direction and, finally, contributing to the development of a faithful image of an object within a turbid medium. The collimation method, also referred to as angular domain imaging (ADI), applies to a see-through configuration where the incident collimated light beam can be aligned with the collimator in a transillumination mode of operation. In this paper, we present angular domain optical projection tomography (ADOPT), a method that can extract depth information of optical contrast in turbid media with high longitudinal resolution based on ADI technology. The resolution of the ADI system has been tested over various depths in a 5 cm optical cuvette using a resolution target suspended in a homogeneous turbid medium. The ADOPT system reconstructed images from a series of angular domain projections collected at angular intervals. The system was used to measure the attenuation of an absorbing target in transmission mode (t-ADOPT) and to measure the light emitting from a fluorescent target (f-ADOPT). Tissue-mimicking phantoms were used to validate the performance of the method. In the t-ADOPT configuration, a background scattered light estimation and subtraction methodology was introduced to improve the imaging contrast. A target consisting of two graphite rods (0.9 mm diameter) was suspended in the cuvette by a rotation stage. An Indocyanine Green-filled glass rod was used as an imaging target in the f-ADOPT arrangement. The target was placed in a manner such that the line of laser light was perpendicular to the longitudinal axis of the rods. Several projections were collected at increments of 1.8 degrees and compiled into a sinogram. A transverse image was reconstructed from the sinogram by using filtered backprojection and image contrast was improved by experimental scatter measurements using a wedge prism and an image processing algorithm. The submillimeter target embedded in a 2 cm thick scattering medium (reduced scattering coefficient < or = 2.4 cm(-1)) was discernable in both the sinograms and the reconstructed images. In the f-ADOPT system, fluorescent line targets <1 cm in diameter embedded in a 2 cm thick scattering medium (reduced scattering coefficient < or = 0.8 cm(-1)) were discernable in both the sinograms and the reconstructed images. The proposed method could be used as the basis to construct an optical tomographic scanner for simultaneous absorption and fluorescence-based imaging of biological specimens (i.e., up to 7 mm across).
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Affiliation(s)
- Fartash Vasefi
- The School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
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17
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Erickson SJ, Godavarty A. Hand-held based near-infrared optical imaging devices: A review. Med Eng Phys 2009; 31:495-509. [DOI: 10.1016/j.medengphy.2008.10.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 07/12/2008] [Accepted: 10/15/2008] [Indexed: 11/15/2022]
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18
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Ge J, Zhu B, Regalado S, Godavarty A. Three-dimensional fluorescence-enhanced optical tomography using a hand-held probe based imaging system. Med Phys 2008; 35:3354-63. [PMID: 18697559 DOI: 10.1118/1.2940603] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Hand-held based optical imaging systems are a recent development towards diagnostic imaging of breast cancer. To date, all the hand-held based optical imagers are used to perform only surface mapping and target localization, but are not capable of demonstrating tomographic imaging. Herein, a novel hand-held probe based optical imager is developed towards three-dimensional (3-D) optical tomography studies. The unique features of this optical imager, which primarily consists of a hand-held probe and an intensified charge coupled device detector, are its ability to; (i) image large tissue areas (5 x 10 sq. cm) in a single scan, (ii) perform simultaneous multiple point illumination and collection, thus reducing the overall imaging time; and (iii) adapt to varying tissue curvatures, from a flexible probe head design. Experimental studies are performed in the frequency domain on large slab phantoms (approximately 650 ml) using fluorescence target(s) under perfect uptake (1:0) contrast ratios, and varying target depths (1-2 cm) and X-Y locations. The effect of implementing simultaneous over sequential multiple point illumination towards 3-D tomography is experimentally demonstrated. The feasibility of 3-D optical tomography studies has been demonstrated for the first time using a hand-held based optical imager. Preliminary fluorescence-enhanced optical tomography studies are able to reconstruct 0.45 ml target(s) located at different target depths (1-2 cm). However, the depth recovery was limited as the actual target depth increased, since only reflectance measurements were acquired. Extensive tomography studies are currently carried out to determine the resolution and performance limits of the imager on flat and curved phantoms.
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Affiliation(s)
- Jiajia Ge
- Optical Imaging Laboratory, Department of Biomedical Engineering, Florida International University, Miami, Florida 33174, USA
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19
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Jayachandran B, Ge J, Regalado S, Godavarty A. Design and development of a hand-held optical probe toward fluorescence diagnostic imaging. JOURNAL OF BIOMEDICAL OPTICS 2007; 12:054014. [PMID: 17994902 DOI: 10.1117/1.2799193] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Near-infrared optical imaging is an emerging noninvasive technology toward breast cancer diagnosis. The optical imaging systems available to date are limited either by flexibility to image any given breast volume, patient comfort, or instrument portability. Here, a hand-held optical probe is designed and developed, 1. employing a unique measurement scheme of simultaneous multiple point illumination and collection for rapid data acquisition and minimal patient discomfort, and 2. employing a curved probe head such that it allows flexible imaging of tissue curvatures. Simulation studies are carried out on homogeneous slab phantoms (5x10x8 cc) to determine an appropriate source-detector configuration for the probe head. These design features are implemented in the development of the probe, which consisted of six simultaneous illuminating and 165 simultaneous collecting fibers, spaced 0.5 cm apart on a 5x10 sq-cm probe head. Simulation studies on 3-D slab and curved phantoms demonstrate an increase in the total area of predicted fluorescence amplitude and overall signal strength on using simultaneous multiple point sources over a single point source. The probe is designed and developed such that on coupling with a detection system in the future, the hand-held probe based imager can be clinically assessed toward cancer diagnostic imaging.
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Affiliation(s)
- Bhavani Jayachandran
- Florida International University, Optical Imaging Laboratory, Department of Biomedical Engineering, Miami, Florida 33174, USA
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20
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Nishidate I, Goto M, Sasaki Y, Yuasa T, Devaraj B, Niizeki K, Akatsuka T. Near-infrared laser tomographic imaging with right-angled scattered coherent light using an optical heterodyne-detection-based confocal scanning system. APPLIED OPTICS 2007; 46:2123-30. [PMID: 17384729 DOI: 10.1364/ao.46.002123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We demonstrate, what is to the best of our knowledge, a novel optical tomographic method for the visualization of the inner structure of scattering media such as biological tissue in the near-infrared region. We constructed a scanning confocal imaging system with a cross-axes arrangement using optical fibers. This system is based on the optical heterodyne technique and enables the detection of very weak coherence photons that are generated in the spatially restricted confocal region and scattered laterally (90 degrees ) against an incident beam. To evaluate the fundamental imaging capabilities of the system, we assessed measurements from scattering phantoms composed of an Intralipid suspension with varying volume concentrations. The results of this study demonstrate that the right-angled scattered light adheres to the Lambert-Beer law and that the present system can detect light propagating through a distance of approximately 31l of the mean free path. An inclusion as small as 100 microm can be discriminated in a scattering media with an optical thickness of 4. We investigated the potential of the proposed system for imaging biological tissues in preliminary experiments using samples of chicken breast tissue.
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Affiliation(s)
- Izumi Nishidate
- Department of Bio-System Engineering, Yamagata University, Yonezawa, Japan.
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21
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Li C, Zhao H, Anderson B, Jiang H. Multispectral breast imaging using a ten-wavelength, 64 x 64 source/detector channels silicon photodiode-based diffuse optical tomography system. Med Phys 2006; 33:627-36. [PMID: 16878566 DOI: 10.1118/1.2171508] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We describe a compact diffuse optical tomography system specifically designed for breast imaging. The system consists of 64 silicon photodiode detectors, 64 excitation points, and 10 diode lasers in the near-infrared region, allowing multispectral, three-dimensional optical imaging of breast tissue. We also detail the system performance and optimization through a calibration procedure. The system is evaluated using tissue-like phantom experiments and an in vivo clinic experiment. Quantitative two-dimensional (2D) and three-dimensional (3D) images of absorption and reduced scattering coefficients are obtained from these experiments. The ten-wavelength spectra of the extracted reduced scattering coefficient enable quantitative morphological images to be reconstructed with this system. From the in vivo clinic experiment, functional images including deoxyhemoglobin, oxyhemoglobin, and water concentration are recovered and tumors are detected with correct size and position compared with the mammography.
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Affiliation(s)
- Changqing Li
- Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611-6131, USA
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22
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Yates TD, Hebden JC, Gibson AP, Enfield L, Everdell NL, Arridge SR, Delpy DT. Time-resolved optical mammography using a liquid coupled interface. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:054011. [PMID: 16292971 DOI: 10.1117/1.2063327] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A method has been devised for generating three-dimensional optical images of the breast using a 32-channel time-resolved system and a liquid-coupled interface. The breast is placed in a hemispherical cup surrounded by sources and detectors, and the remaining space is filled with a fluid with tissue-like optical properties. This approach has three significant benefits. First, cups can accommodate a large range of breast sizes, enabling the entire volume of the breast to be sampled. Second, the coupling of the source and detector optics at the surface is constant and independent of the subject, enabling intensity measurements to be employed in the image reconstruction. Third, the external geometry of the reconstructed volume is known exactly. Images of isolated targets with contrasting absorbing and scattering properties have been acquired, and the performance of the system has been evaluated in terms of the contrast, spatial resolution, and localization accuracy. These parameters were strongly dependent on the location of the targets within the imaged volume. Preliminary images of a healthy human subject are also presented, which reveal subtle heterogeneity, particularly in the distribution of scatter. The ability to detect an absorbing target adjacent to the breast is also demonstrated.
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Affiliation(s)
- Tara D Yates
- University College London, Department of Medical Physics & Bioengineering, London WC1E 6BT, United Kingdom
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23
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Yates T, Hebden JC, Gibson A, Everdell N, Arridge SR, Douek M. Optical tomography of the breast using a multi-channel time-resolved imager. Phys Med Biol 2005; 50:2503-17. [PMID: 15901951 DOI: 10.1088/0031-9155/50/11/005] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A time-resolved optical tomography system has been used to generate cross-sectional images of the human breast. Images are reconstructed using an iterative, nonlinear algorithm and measurements of mean photon flight time relative to those acquired on a homogeneous reference phantom. Thirty-eight studies have been performed on three healthy volunteers and 21 patients with a variety of breast lesions including cancer. We have successfully detected 17 out of 19 lesions, and shown that optical images of the healthy breast of the same volunteer display a heterogeneity which is repeatable over a period of months. However, results also indicate that the lack of accurate quantitation of optical parameters and limited morphological information limits the ability to characterize different types of lesions and distinguish benign from malignant tissues. Drawbacks of our current methodology and plans for overcoming them are discussed.
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Affiliation(s)
- Tara Yates
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT, UK
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24
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Markel VA, Schotland JC. Multiple projection optical diffusion tomography with plane wave illumination. Phys Med Biol 2005; 50:2351-64. [PMID: 15876672 DOI: 10.1088/0031-9155/50/10/012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We describe a new data collection scheme for optical diffusion tomography in which plane wave illumination is combined with multiple projections in the slab imaging geometry. Multiple projection measurements are performed by rotating the slab around the sample. The advantage of the proposed method is that the measured data are more compatible with the dynamic range of most commonly used detectors. At the same time, multiple projections improve image quality by mutually interchanging the depth and transverse directions, and the scanned (detection) and integrated (illumination) surfaces. Inversion methods are derived for image reconstructions with extremely large data sets. Numerical simulations are performed for fixed and rotated slabs.
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Affiliation(s)
- Vadim A Markel
- Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA.
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25
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Hebden JC, Yates TD, Gibson A, Everdell N, Arridge SR, Chicken DW, Douek M, Keshtgar MRS. Monitoring recovery after laser surgery of the breast with optical tomography: a case study. APPLIED OPTICS 2005; 44:1898-1904. [PMID: 15813526 DOI: 10.1364/ao.44.001898] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Results are presented of a study to monitor the changes in the optical properties of breast tissue over a 12-month period after interstitial laser photocoagulation treatment of a fibroadenoma. The study involved generating cross-sectional images of the breast with a multichannel time-resolved imaging system and a nonlinear image reconstruction algorithm. Images of the internal absorbing and scattering properties revealed the expected initial inflammatory response, followed by the development of low-scattering cysts consistent with corresponding ultrasound examinations. Although results indicate that purely qualitative images can potentially provide clinically valuable data, means of enhancing diagnostic information by overcoming present limitations of the approach are discussed.
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Affiliation(s)
- Jeremy C Hebden
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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26
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Kanmani B, Vasu RM. Diffuse optical tomography using intensity measurements and the a priori acquired regions of interest: theory and simulations. Phys Med Biol 2004; 50:247-64. [PMID: 15742942 DOI: 10.1088/0031-9155/50/2/005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Light transmission data collected around an object show large variation with source-detector separation owing to the presence of single or multiple inhomogeneous regions in the object. This variation in the measured intensity is made use of to reconstruct regions of the inhomogeneous inclusions. In addition, it is possible to select a set of data from the above which is most likely least affected by the presence of the inhomogeneity, and estimate reasonably accurately the background optical properties from it. The reconstructed region is found to always contain the inhomogeneity and is of size approximately 140% by area of the inhomogeneity. With the regions to be reconstructed a priori known, a model-based iterative reconstruction procedure for reconstructing the optical properties of the region converged five times faster than without such information. It is also shown that whereas for the full object, a view-based propagation-backpropagation reconstruction procedure failed to converge, owing to large underdeterminacy of the problem, a smaller problem attempting to reconstruct a priori specified regions of interest converged and did so faster than a non-view-based approach for similar objects. Reconstruction results are presented from simulated transmitted intensity data from the following objects with regions of inhomogeneity in both absorption and scattering: (i) single centrally located inhomogeneity, (ii) two off-centred inhomogeneous regions of equal size and contrast (iii) two off-centred inhomogeneous regions of unequal size and equal contrast and (iv) two off-centred inhomogeneous regions of unequal size and contrast. Whereas the model-based iterative image reconstruction procedure gave good convergence in the first, second and third cases, in the fourth case the reconstructions failed to recover the exact numerical value of the optical properties in the higher contrast region.
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Affiliation(s)
- B Kanmani
- Department of Instrumentation, Indian Institute of Science, Bangalore 560 012, India
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27
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Srinivasan R, Singh M. Multislice Tomographic Imaging and Analysis of Human Breast-Equivalent Phantoms and Biological Tissues. IEEE Trans Biomed Eng 2004; 51:1830-7. [PMID: 15490830 DOI: 10.1109/tbme.2004.831527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A laser transillumination tomographic system, consisting of electrical, optical, mechanical, and software components, to obtain multislice images of tissue-equivalent breast phantoms and biological tissues, is developed. The tissue-equivalent phantoms are prepared from paraffin wax mixed with wax color pigments by matching their surface backscattered profiles as measured by multiprobe laser reflectometer, with that of respective tissues. The optical parameters of these phantoms are determined by matching their reflectance profiles with that as obtained by Monte Carlo simulation of optical scattering. For multislice tomographic analysis conical breast phantoms of height 80.0 mm and 80.0 mm base diameter with inclusions of different optical properties and dimensions are developed. The resolution of the inclusions in the tomograms depends on their sizes and optical parameters. The minimum size of the inclusion as detected by this procedure in a slice of diameter 50.0 mm is 3.0 mm. The structural variation as observed in the tomograms of phantoms of combination of biological tissues indicates its possible applications in detecting the abnormalities developing in human healthy soft tissues.
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Affiliation(s)
- R Srinivasan
- Indian Institute of Technology-Madras, Tamilnadu 600036, India
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28
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Abstract
We propose a new approach to optical diffusion tomography that incorporates two orthogonal projections. All the data obtained in a double projection measurement are treated simultaneously. The second projection improves image quality due to the fact that the depth and transverse directions are interchanged. An image reconstruction algorithm is derived and illustrated with simulations. It is shown that the spatial resolution of images improves by a factor of 4-5 due to the second projection.
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Affiliation(s)
- Vadim A Markel
- Departments of Radiology and Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Garofalakis A, Zacharakis G, Filippidis G, Sanidas E, Tsiftsis DD, Ntziachristos V, Papazoglou TG, Ripoll J. Characterization of the reduced scattering coefficient for optically thin samples: theory and experiments. ACTA ACUST UNITED AC 2004. [DOI: 10.1088/1464-4258/6/7/012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Hielscher AH, Bartel S. Parallel programming of gradient-based iterative image reconstruction schemes for optical tomography. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2004; 73:101-113. [PMID: 14757254 DOI: 10.1016/s0169-2607(03)00020-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Optical tomography (OT) is a fast developing novel imaging modality that uses near-infrared (NIR) light to obtain cross-sectional views of optical properties inside the human body. A major challenge remains the time-consuming, computational-intensive image reconstruction problem that converts NIR transmission measurements into cross-sectional images. To increase the speed of iterative image reconstruction schemes that are commonly applied for OT, we have developed and implemented several parallel algorithms on a cluster of workstations. Static process distribution as well as dynamic load balancing schemes suitable for heterogeneous clusters and varying machine performances are introduced and tested. The resulting algorithms are shown to accelerate the reconstruction process to various degrees, substantially reducing the computation times for clinically relevant problems.
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Affiliation(s)
- Andreas H Hielscher
- Departments of Biomedical Engineering and Radiology, Columbia University, 500 West 120th Street, MC 8904, New York, NY 10027, USA.
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Boas DA, Dale AM, Franceschini MA. Diffuse optical imaging of brain activation: approaches to optimizing image sensitivity, resolution, and accuracy. Neuroimage 2004; 23 Suppl 1:S275-88. [PMID: 15501097 DOI: 10.1016/j.neuroimage.2004.07.011] [Citation(s) in RCA: 444] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Accepted: 07/01/2004] [Indexed: 11/18/2022] Open
Abstract
Near-infrared spectroscopy (NIRS) and diffuse optical imaging (DOI) are finding widespread application in the study of human brain activation, motivating further application-specific development of the technology. NIRS and DOI offer the potential to quantify changes in deoxyhemoglobin (HbR) and total hemoglobin (HbT) concentration, thus enabling distinction of oxygen consumption and blood flow changes during brain activation. While the techniques implemented presently provide important results for cognition and the neurosciences through their relative measures of HbR and HbT concentrations, there is much to be done to improve sensitivity, accuracy, and resolution. In this paper, we review the advances currently being made and issues to consider for improving optical image quality. These include the optimal selection of wavelengths to minimize random and systematic error propagation in the calculation of the hemoglobin concentrations, the filtering of systemic physiological signal clutter to improve sensitivity to the hemodynamic response to brain activation, the implementation of overlapping measurements to improve image spatial resolution and uniformity, and the utilization of spatial prior information from structural and functional MRI to reduce DOI partial volume error and improve image quantitative accuracy.
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Affiliation(s)
- David A Boas
- Anthinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
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Lyubimov VV. Application of transform algorithms to high-resolution image reconstruction in optical diffusion tomography of strongly scattering media. JOURNAL OF ELECTRONIC IMAGING 2003; 12:602. [DOI: 10.1117/1.1604119] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
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Prince S, Kolehmainen V, Kaipio JP, Franceschini MA, Boas D, Arridge SR. Time-series estimation of biological factors in optical diffusion tomography. Phys Med Biol 2003; 48:1491-504. [PMID: 12817933 DOI: 10.1088/0031-9155/48/11/301] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We apply state space estimation techniques to the time-varying reconstruction problem in optical tomography. We develop a stochastic model for describing the evolution of quasi-sinusoidal medical signals such as the heartbeat, assuming these are represented as a known frequency with randomly varying amplitude and phase. We use the extended Kalman filter in combination with spatial regularization techniques to reconstruct images from highly under-determined time-series data. This system also naturally segments activity belonging to different biological processes. We present reconstructions of simulated data and of real data recorded from the human motor cortex (Franceschini et al 2000 Optics Express 6 49-57). It is argued that the application of these time-series techniques improves both the fidelity and temporal resolution of reconstruction in optical tomography.
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Affiliation(s)
- Simon Prince
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 113576.
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Gao F, Tanikawa Y, Zhao H, Yamada Y. Semi-three-dimensional algorithm for time-resolved diffuse optical tomography by use of the generalized pulse spectrum technique. APPLIED OPTICS 2002; 41:7346-7358. [PMID: 12477128 DOI: 10.1364/ao.41.007346] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Although a foil three-dimensional (3-D) reconstruction with both 3-D forward and inverse models provide, the optimal solution for diffuse optical tomography (DOT), because of the 3-D nature of photon diffusion in tissue, it is computationally costly for both memory requirement and execution time in a conventional computing environment. Thus in practice there is motivation to develop an image reconstruction algorithm with dimensional reduction based on some modeling approximations. Here we have implemented a semi-3-D modified generalized pulse spectrum technique for time-resolved DOT, where a two-dimensional (2-D) distribution of optical properties is approximately assumed, while we retain 3-D distribution of photon migration in tissue. We have validated the proposed algorithm by reconstructing 3-D structural test objects from both numerically simulated and experimental date. We demonstrate our algorithm by comparing it with the calibrated 2-D reconstruction that is in widespread use as a shortcut to 3-D imaging and proving that the semi-3-D algorithm outperforms the calibrated 2-D algorithm.
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Affiliation(s)
- Feng Gao
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, 1-2 Namiki, Tsukuba, Ibaraki 305-8564, Japan.
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36
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Xu Y, Gu X, Khan T, Jiang H. Absorption and scattering images of heterogeneous scattering media can be simultaneously reconstructed by use of dc data. APPLIED OPTICS 2002; 41:5427-5437. [PMID: 12211574 DOI: 10.1364/ao.41.005427] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present a carefully designed phantom experimental study aimed to provide solid evidence that both absorption and scattering images of heterogeneous scattering media can be reconstructed independently from dc data. We also study the important absorption-scattering cross-talk issue. In this regard, we develop a simple normalizing scheme that is incorporated into our nonlinear finite-element-based reconstruction algorithm. Our results from the controlled phantom experiments show that the cross talk of an absorption object appearing in scattering images can be eliminated and that the cross talk of a scattering object appearing in absorption images can be reduced considerably. In addition, these carefully designed phantom experiments clearly suggest that both absorption and scattering images can be simultaneously recovered and quantitatively separated in highly scattering media by use of dc measurements. Finally, we discuss our results in light of recent theoretical findings on nonuniqueness for dc image reconstruction.
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Affiliation(s)
- Yong Xu
- Department of Physics and Astronomy, Clemson University, South Carolina 29634, USA
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37
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Pogue BW, Song X, Tosteson TD, McBride TO, Jiang S, Paulsen KD. Statistical analysis of nonlinearly reconstructed near-infrared tomographic images: Part I--Theory and simulations. IEEE TRANSACTIONS ON MEDICAL IMAGING 2002; 21:755-63. [PMID: 12374313 DOI: 10.1109/tmi.2002.801155] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Near-infrared (NIR) diffuse tomography is an emerging method for imaging the interior of tissues to quantify concentrations of hemoglobin and exogenous chromophores non-invasively in vivo. It often exploits an optical diffusion model-based image reconstruction algorithm to estimate spatial property values from measurements of the light flux at the surface of the tissue. In this study, mean-squared error (MSE) over the image is used to evaluate methods for regularizing the ill-posed inverse image reconstruction problem in NIR tomography. Estimates of image bias and image standard deviation were calculated based upon 100 repeated reconstructions of a test image with randomly distributed noise added to the light flux measurements. It was observed that the bias error dominates at high regularization parameter values while variance dominates as the algorithm is allowed to approach the optimal solution. This optimum does not necessarily correspond to the minimum projection error solution, but typically requires further iteration with a decreasing regularization parameter to reach the lowest image error. Increasing measurement noise causes a need to constrain the minimum regularization parameter to higher values in order to achieve a minimum in the overall image MSE.
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Affiliation(s)
- Brian W Pogue
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA.
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38
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Lyubimov VV, Kalintsev AG, Konovalov AB, Lyamtsev OV, Kravtsenyuk OV, Murzin AG, Golubkina OV, Mordvinov GB, Soms LN, Yavorskaya LM. Application of the photon average trajectories method to real-time reconstruction of tissue inhomogeneities in diffuse optical tomography of strongly scattering media. Phys Med Biol 2002; 47:2109-28. [PMID: 12118604 DOI: 10.1088/0031-9155/47/12/308] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The possibility of application of the photon average trajectories (PAT) method to real-time reconstruction of tissue inhomogeneities in diffuse optical tomography of strongly scattering media has been substantiated. By this method, the inverse problem is reduced to solution of the integral equation with integration along a conditional PAT. Such an approach allows the standard fast algebraic algorithms commonly used in projection computed tomography to be applied to diffuse optical image reconstruction. To demonstrate the capabilities of the PAT method, a numerical experiment on cross-sectional reconstruction of cylindrical strongly scattering objects with absorbing inhomogeneities has been done. Relative shadows caused by inhomogeneities are simulated via numerical solution of the non-stationary diffusion equation. To solve the inverse problem, the QR-factorization least-squares algorithm and the multiplicative algebraic reconstruction technique are used. The results are compared with those obtained by a well-known software package for temporal optical absorption and scattering tomography based on multiple solution of the diffusion equation. It is shown that the PAT method allows reconstruction of the optical structure of objects with comparable accuracy while saving reconstruction time considerably.
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39
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Zhao H, Gao F, Tanikawa Y, Onodera Y, Ohmi M, Haruna M, Yamada Y. Imaging of in vitro chicken leg using time-resolved near-infrared optical tomography. Phys Med Biol 2002; 47:1979-93. [PMID: 12108779 DOI: 10.1088/0031-9155/47/11/310] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Near-infrared optical imaging gains much attention because of its noninvasiveness and deep penetration depths into tissue. Here, we report near-infrared optical tomographic imaging of an in vitro chicken leg from time-resolved measurements. The in vitro chicken leg, dipped in a cylindrical container filled with diluted Intralipid-10% solution, was imaged with a multichannel time-resolved imaging system. A two-dimensional reconstruction algorithm based on a modified generalized pulse spectrum technique has been developed to reconstruct the images of both the absorption and reduced scattering coefficients simultaneously and quickly. The results demonstrate that a simultaneous reconstruction of absorption and reduced scattering coefficients from time-resolved measurement has a potential to reveal the changes in the optical properties associated with not only the physiological information but also the anatomical structure of the organ.
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Affiliation(s)
- Huijuan Zhao
- National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
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40
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Gao F, Zhao H, Yamada Y. Improvement of image quality in diffuse optical tomography by use of full time-resolved data. APPLIED OPTICS 2002; 41:778-91. [PMID: 11993926 DOI: 10.1364/ao.41.000778] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In the field of diffuse optical tomography (DOT), it is widely accepted that time-resolved (TR) measurement can provide the richest information on photon migration in a turbid medium, such as biological tissue. However, the currently available image reconstruction algorithms for TR DOT are based mostly on the cw component or some featured data types of original temporal profiles, which are related to the solution of a time-independent diffusion equation. Although this methodology can greatly simplify the reconstruction process, it suffers from low spatial resolution and poor quantitativeness owing to the limitation of effectively applicable data types. To improve image quality, it has been argued that exploiting the full TR data is essential. We propose implementation of a DOT algorithm by using full TR data and furthermore a variant algorithm with time slices of TR data to alleviate the computational complexity and enhance noise robustness. Compared with those algorithms where the featured data types are used, our evaluations on the spatial resolution and quantitativeness show that a significant improvement in imaging quality can be achieved when full TR data are used, which convinces the DOT community of the potential advantage of the TR domain over cw and frequency domains.
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Affiliation(s)
- Feng Gao
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Tsukuba, lbaraki, Japan.
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41
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Xu Y, Iftimia N, Jiang H, Key LL, Bolster MB. Three-dimensional diffuse optical tomography of bones and joints. JOURNAL OF BIOMEDICAL OPTICS 2002; 7:88-92. [PMID: 11818016 DOI: 10.1117/1.1427336] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2001] [Revised: 08/23/2001] [Accepted: 08/24/2001] [Indexed: 05/20/2023]
Abstract
We present for the first time full three-dimensional (3D) volumetric reconstruction of absorption images of in vitro and in vivo bones and joints from near-infrared tomographic measurements. Imaging experiments were conducted on human finger and chicken bones embedded in cylindrical scattering media using a Clemson multichannel diffuse optical imager. The volumetric optical images were recovered with our 3D finite element based reconstruction algorithm. Our results show that 3D imaging methods can provide details of the joint structure/composition that would be impossible from two-dimensional imaging methods.
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Affiliation(s)
- Yong Xu
- Clemson University, Biomedical Optics Laboratory, Department of Physics and Astronomy, Clemson, South Carolina 29634-0978, USA
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42
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Jiang H, Xu Y, Iftimia N, Eggert J, Klove K, Baron L, Fajardo L. Three-dimensional optical tomographic imaging of breast in a human subject. IEEE TRANSACTIONS ON MEDICAL IMAGING 2001; 20:1334-40. [PMID: 11811833 DOI: 10.1109/42.974928] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present for the first time a full three-dimensional (3-D) reconstruction of absorption images of breast from continuous-wave (cw) measurements performed on a premenopausal woman. Our 3-D optical images clearly reveal a large primary tumor as well as a small secondary tumor in a separate location of the breast. The multiple tumors identified by our 3-D optical imaging have been confirmed by the subsequent biopsy examination of the breast. Quantitative information of the optical images obtained is provided in terms of the location, size, and absorption coefficient of the tumors.
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Affiliation(s)
- H Jiang
- Department of Physics & Astronomy, Clemson University, SC 29634-0978, USA.
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43
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Tsuchiya Y. Photon path distribution and optical responses of turbid media: theoretical analysis based on the microscopic Beer-Lambert law. Phys Med Biol 2001; 46:2067-84. [PMID: 11512611 DOI: 10.1088/0031-9155/46/8/303] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A concise theoretical treatment has been developed to describe the optical responses of a highly scattering inhomogeneous medium using functions of the photon path distribution (PPD). The treatment is based on the microscopic Beer-Lambert law and has been found to yield a complete set of optical responses by time- and frequency-domain measurements. The PPD is defined for possible photons having a total zigzag pathlength of l between the points of light input and detection. Such a distribution is independent of the absorption properties of the medium and can be uniquely determined for the medium under quantification. Therefore, the PPD can be calculated with an imaginary reference medium having the same optical properties as the medium under quantification except for the absence of absorption. One of the advantages of this method is that the optical responses, the total attenuation, the mean pathlength, etc are expressed by functions of the PPD and the absorption distribution.
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Affiliation(s)
- Y Tsuchiya
- Central Research Laboratory, Hamamatsu Photonics K.K., Japan.
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44
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Hebden JC, Veenstra H, Dehghani H, Hillman EM, Schweiger M, Arridge SR, Delpy DT. Three-dimensional time-resolved optical tomography of a conical breast phantom. APPLIED OPTICS 2001; 40:3278-87. [PMID: 11958270 DOI: 10.1364/ao.40.003278] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A 32-channel time-resolved imaging device for medical optical tomography has been employed to evaluate a scheme for imaging the human female breast. The fully automated instrument and the reconstruction procedure have been tested on a conical phantom with tissue-equivalent optical properties. The imaging protocol has been designed to obviate compression of the breast and the need for coupling fluids. Images are generated from experimental data with an iterative reconstruction algorithm that employs a three-dimensional (3D) finite-element diffusion-based forward model. Embedded regions with twice the background optical properties are revealed in separate 3D absorption and scattering images of the phantom. The implications for 3D time-resolved optical tomography of the breast are discussed.
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Affiliation(s)
- J C Hebden
- Department of Medical Physics and Bioengineering, University College London, UK.
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45
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Hillman EM, Hebden JC, Schweiger M, Dehghani H, Schmidt FE, Delpy DT, Arridge SR. Time resolved optical tomography of the human forearm. Phys Med Biol 2001; 46:1117-30. [PMID: 11324955 DOI: 10.1088/0031-9155/46/4/315] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A 32-channel time-resolved optical imaging instrument has been developed principally to study functional parameters of the new-born infant brain. As a prelude to studies on infants, the device and image reconstruction methodology have been evaluated on the adult human forearm. Cross-sectional images were generated using time-resolved measurements of transmitted light at two wavelengths. All data were acquired using a fully automated computer-controlled protocol. Images representing the internal scattering and absorbing properties of the arm are presented, as well as images that reveal physiological changes during a simple finger flexion exercise. The results presented in this paper represent the first simultaneous tomographic reconstruction of the internal scattering and absorbing properties of a clinical subject using purely temporal data, with additional co-registered difference images showing repeatable absorption changes at two wavelengths in response to exercise.
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Affiliation(s)
- E M Hillman
- Department of Medical Physics and Bioengineering, University College London, UK
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46
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Schmitz CH, Graber HL, Luo H, Arif I, Hira J, Pei Y, Bluestone A, Zhong S, Andronica R, Soller I, Ramirez N, Barbour SL, Barbour RL. Instrumentation and calibration protocol for imaging dynamic features in dense-scattering media by optical tomography. APPLIED OPTICS 2000; 39:6466-86. [PMID: 18354661 DOI: 10.1364/ao.39.006466] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Instrumentation is described that is suitable for acquiring multisource, multidetector, time-series optical data at high sampling rates (up to 150 Hz) from tissues having arbitrary geometries. The design rationale, calibration protocol, and measured performance features are given for both a currently used, CCD-camera-based instrument and a new silicon-photodiode-based system under construction. Also shown are representative images that we reconstructed from data acquired in laboratory studies using the described CCD-based instrument.
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Affiliation(s)
- C H Schmitz
- Downstate Medical Center, State University of New York, Box 25, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
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47
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Gao F, Poulet P, Yamada Y. Simultaneous mapping of absorption and scattering coefficients from a three-dimensional model of time-resolved optical tomography. APPLIED OPTICS 2000; 39:5898-910. [PMID: 18354594 DOI: 10.1364/ao.39.005898] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
A Newton-Raphson inversion algorithm has been extended for simultaneous absorption and scattering reconstruction of fully three-dimensional (3D) diffuse optical tomographic imaging from time-resolved measurements. The proposed algorithm is derived from the efficient computation of the Jacobian matrix of the forward model and uses either the algebraic reconstruction technique or truncated singular-value decomposition as the linear inversion tool. Its validation was examined with numerically simulated data from 3-D finite-element discretization models of tissuelike phantoms, with several combinations of geometric and optical properties, as well as two commonly used source-detector configurations. Our results show that the fully 3-D image reconstruction of an object can be achieved with reasonable quality when volumetric light propagation in tissues is considered, and temporal information from the measurements can be effectively employed. Also, we investigated the conditions under which 3-D issues could be approximately addressed with two-dimensional reconstruction algorithms and further demonstrated that these conditions are seldom predictable or attainable in practice. Thus the application of 3-D algorithms to realistic situations is necessary.
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48
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Iftimia N, Jiang H. Quantitative optical image reconstruction of turbid media by use of direct-current measurements. APPLIED OPTICS 2000; 39:5256-61. [PMID: 18354522 DOI: 10.1364/ao.39.005256] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We present a detailed experimental study concerning quantitative optical property reconstruction of heterogeneous turbid media by use of absolute dc data only. We performed experiments by using tissuelike phantoms in both single-target and multitarget configurations in which variations in target size and optical contrast with the background were explored. Our results show that both scattering and absorption images can be reconstructed quantitatively by use of dc data only, whereas it was impossible to obtain such quantitative information in previously reported studies. We believe that this improvement is primarily a result of the realization of a novel data preprocessing/optimization scheme for accurately determining several critical parameters needed for reconstruction. The use of this data preprocessing/optimization scheme also eliminates the calibration reference measurement previously required for reconstruction. Experimental confirmation of this scheme is given in detail.
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Affiliation(s)
- N Iftimia
- Department of Physics and Astronomy, Biomedical Optics Laboratory, Clemson University, Clemson, South Carolina 29634-0978, USA
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49
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Painchaud Y, Chatigny S, Morin M, Vernon ML, Beaudry P. Dual-spatial integration for longitudinal localization of inclusions in turbid media. APPLIED OPTICS 2000; 39:4730-4732. [PMID: 18350065 DOI: 10.1364/ao.39.004730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We introduce a technique called dual-spatial integration (DSI) that is used to isolate and enhance inclusions that differ only by their longitudinal placement within a scattering medium. DSI uses three different source-detector configurations to section a scattering medium into three longitudinal zones. This sectioning permits the extraction of structures close to surfaces and the enhancement of those structures located in the central part of the medium. Both the simulation and the experimental results indicate that DSI has potential interest for applications in biomedical imaging such as optical mammography.
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Affiliation(s)
- Y Painchaud
- National Optics Institute (INO), 2740 Einstein, Sainte-Foy, Québec G1P 4S4, Canada.
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50
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Hawrysz DJ, Sevick-Muraca EM. Developments toward diagnostic breast cancer imaging using near-infrared optical measurements and fluorescent contrast agents. Neoplasia 2000; 2:388-417. [PMID: 11191107 PMCID: PMC1507982 DOI: 10.1038/sj.neo.7900118] [Citation(s) in RCA: 269] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2000] [Accepted: 10/10/2000] [Indexed: 11/09/2022]
Abstract
The use of near-infrared (NIR) light to interrogate deep tissues has enormous potential for molecular-based imaging when coupled with NIR excitable dyes. More than a decade has now passed since the initial proposals for NIR optical tomography for breast cancer screening using time-dependent measurements of light propagation in the breast. Much accomplishment in the development of optical mammography has been demonstrated, most recently in the application of time-domain, frequency-domain, and continuous-wave measurements that depend on endogenous contrast owing to angiogenesis and increased hemoglobin absorbance for contrast. Although exciting and promising, the necessity of angiogenesis-mediated absorption contrast for diagnostic optical mammography minimizes the potential for using NIR techniques to assess sentinel lymph node staging, metastatic spread, and multifocality of breast disease, among other applications. In this review, we summarize the progress made in the development of optical mammography, and focus on the emerging work underway in the use of diagnostic contrast agents for the molecular-based, diagnostic imaging of breast.
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Affiliation(s)
- D J Hawrysz
- Department of Chemical Engineering, Texas A&M University, College Station 77843-3122, USA
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