Research Topics
| Hamid DehghaniSummaryAffiliation: Dartmouth Medical School Country: USA Publications
| Collaborators
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Detail Information
Publications
Effects of refractive index on near-infrared tomography of the breastHamid Dehghani
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, New Hampshire 03755 8000, USA
Appl Opt 44:1870-8. 2005..The results suggest that provided the refractive index of breast tissue is approximately 1.3-1.4, their exclusion will have minimal effect on the reconstructed images...- Three-dimensional optical tomography: resolution in small-object imagingHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Appl Opt 42:3117-28. 2003..Furthermore, the accuracy of quantitative imaging is increased to almost 100% of the target values when a priori information regarding the internal structure of imaging domain is utilized... - Multiwavelength three-dimensional near-infrared tomography of the breast: initial simulation, phantom, and clinical resultsHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Appl Opt 42:135-45. 2003.... - Linear single-step image reconstruction in the presence of nonscattering regionsH Dehghani
Department of Medical Physics and Bioengineering, University College London, UK
J Opt Soc Am A Opt Image Sci Vis 19:1162-71. 2002..The errors in quantitative and localization accuracies depend on the size and location of the clear regions... - In vivo hemoglobin and water concentrations, oxygen saturation, and scattering estimates from near-infrared breast tomography using spectral reconstructionSubhadra Srinivasan
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Acad Radiol 13:195-202. 2006.... - Image reconstruction of effective Mie scattering parameters of breast tissue in vivo with near-infrared tomographyXin Wang
Dartmouth College, Department of Physics and Astronomy, Hanover, New Hampshire 03755, USA
J Biomed Opt 11:041106. 2006.... - Spectrally constrained chromophore and scattering near-infrared tomography provides quantitative and robust reconstructionSubhadra Srinivasan
Department of Biomedical Engineering, Thayer School of Engineering, Dartmouth College, P O Box 8000, Hanover, New Hampshire 03755, USA
Appl Opt 44:1858-69. 2005..Accurate quantification was obtained with a mean error of 7.7% for oxygen saturation and 6.2% for total hemoglobin, with minimal cross talk between different parameters... - Spectral priors improve near-infrared diffuse tomography more than spatial priorsBen Brooksby
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, New Hampshire 03755, USA
Opt Lett 30:1968-70. 2005..When both spatial and spectral priors were applied in a healthy volunteer, glandular tissue showed a higher [Hb(T)], water fraction, and scattering power compared to adipose tissue... 
Imaging breast adipose and fibroglandular tissue molecular signatures by using hybrid MRI-guided near-infrared spectral tomographyBen Brooksby
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755, USA
Proc Natl Acad Sci U S A 103:8828-33. 2006..Combined MR and near-infrared tomography provides fundamental molecular information about these tissue types with resolution governed by MR T1 images...- Implementation of a computationally efficient least-squares algorithm for highly under-determined three-dimensional diffuse optical tomography problemsPhaneendra K Yalavarthy
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Med Phys 35:1682-97. 2008..Use of these new alternative forms becomes effective when the ratio of the number of imaging property parameters exceeds the number of measurements by a factor greater than 2... - Characterization of hemoglobin, water, and NIR scattering in breast tissue: analysis of intersubject variability and menstrual cycle changesBrian W Pogue
Thayer School of Engineering, Dartmouth College, 800 Cummings Hall, Hanover, New Hampshire 03755, USA
J Biomed Opt 9:541-52. 2004.... - Breast deformation modelling for image reconstruction in near infrared optical tomographyHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Phys Med Biol 49:1131-45. 2004..Finally, assuming a non-deformed breast shape for image reconstruction is shown to lead to poor quality images since the geometry of the breast is greatly altered, whereas using the correct deformed geometry produces the best images... - Combining near-infrared tomography and magnetic resonance imaging to study in vivo breast tissue: implementation of a Laplacian-type regularization to incorporate magnetic resonance structureBen Brooksby
Dartmouth College, Thayer School of Engineering, 8000 Cummings Hall, Hanover, New Hampshire 03755, USA
J Biomed Opt 10:051504. 2005..This approach is expected to improve recovery of abnormalities within the breast, as the inclusion of structural information increases the accuracy of recovery of embedded heterogeneities, at least in phantom studies... - Near-infrared characterization of breast tumors in vivo using spectrally-constrained reconstructionSubhadra Srinivasan
Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, USA
Technol Cancer Res Treat 4:513-26. 2005..These changes represent potential diagnostic indicators, which can be assessed to characterize breast tumors... - Magnetic-resonance-imaging-coupled broadband near-infrared tomography system for small animal brain studiesHeng Xu
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Appl Opt 44:2177-88. 2005.... - Image analysis methods for diffuse optical tomographyBrian W Pogue
Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, USA
J Biomed Opt 11:33001. 2006..Each of these three major areas of image interpretation and analysis are reviewed in the context of medical imaging as well as how they are used to quantify the performance of diffuse optical imaging of tissue... - Improved quantification of small objects in near-infrared diffuse optical tomographySubhadra Srinivasan
Dartmouth College, Thayer School of Engineering, Hanover, NH 03755, USA
J Biomed Opt 9:1161-71. 2004..The algorithm is successfully applied to clinical data from a subject with a breast abnormality to yield quantitatively increased absorption coefficients, which enhances the contrast to 3.8 compared to 1.23 previously... - Receiver operating characteristic and location analysis of simulated near-infrared tomography imagesXiaomei Song
Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, USA
J Biomed Opt 12:054013. 2007..Interobserver variance performance in detecting objects in these images was low, suggesting that because of the low spatial resolution, detection tasks with NIR tomography is likely consistent between human observers... - Automated region detection based on the contrast-to-noise ratio in near-infrared tomographyXiaomei Song
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Appl Opt 43:1053-62. 2004..4. A new linear convolution method of CNR calculation was developed for automated region of interest (ROI) detection... - Image-guided optical spectroscopy provides molecular-specific information in vivo: MRI-guided spectroscopy of breast cancer hemoglobin, water, and scatterer sizeColin M Carpenter
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 32:933-5. 2007..Integration of molecular spectroscopy into standard clinical MRI can be achieved with this approach to spectral tomography... - The effects of internal refractive index variation in near-infrared optical tomography: a finite element modelling approachHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Phys Med Biol 48:2713-27. 2003.... - Absorption and scattering imaging of tissue with steady-state second-differential spectral-analysis tomographyHeng Xu
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 29:2043-5. 2004..The steady-state broadband CCD system has the potential to provide accurate chromophore imaging without the technological complexity of time- or frequency-domain systems... - Excitation patterns in three-dimensional electrical impedance tomographyHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Physiol Meas 26:S185-97. 2005..However, in terms of quantitative imaging an excitation pattern where all electrode layers are in phase produces better results... - Video-rate near-infrared optical tomography using spectrally encoded parallel light deliveryDaqing Piao
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 30:2593-5. 2005..35 mm diameter inclusion with an absorption coefficient of 0.01 mm(-1) and a reduced scattering coefficient of 1.5 mm(-1) that is moving along a circular path inside a 1% Intralipid solution... - Subsurface diffuse optical tomography can localize absorber and fluorescent objects but recovered image sensitivity is nonlinear with depthDax S Kepshire
Thayer School of Engineering, Dartmouth College, New Hampshire 03755, USA
Appl Opt 46:1669-78. 2007..However, increases in tissue curvature and/or the addition of prior information are expected to improve the linearity of the response. The potential for this type of imaging technique to serve as a surgical guide is highlighted... - Tissue drug concentration determines whether fluorescence or absorption measurements are more sensitive in diffuse optical tomography of exogenous contrast agentsScott C Davis
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Appl Opt 48:D262-72. 2009..Specifically, fluorescence measurements are favorable if background drug concentrations are below 135-200 nM for LuTex and 25-50 nM for ICG, while absorption measurements are more sensitive above these ranges... - Magnetic resonance-coupled fluorescence tomography scanner for molecular imaging of tissueScott C Davis
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Rev Sci Instrum 79:064302. 2008..A pilot murine study using an orthotopic glioma tumor model demonstrates optical-MRI imaging of an epidermal growth factor receptor targeted fluorescent probe in vivo... - A microcomputed tomography guided fluorescence tomography system for small animal molecular imagingDax Kepshire
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Rev Sci Instrum 80:043701. 2009..This multimodality imaging system will have a wide range of applications in preclinical cancer research ranging from studies of the tumor microenvironment and treatment efficacy for emerging cancer therapeutics... - Spectral derivative based image reconstruction provides inherent insensitivity to coupling and geometric errorsHeng Xu
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 30:2912-4. 2005.... - Fluorescence tomography characterization for sub-surface imaging with protoporphyrin IXDax Kepshire
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Opt Express 16:8581-93. 2008.... - Interpreting hemoglobin and water concentration, oxygen saturation, and scattering measured in vivo by near-infrared breast tomographySubhadra Srinivasan
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Proc Natl Acad Sci U S A 100:12349-54. 2003..These breast constituents vary significantly between individuals and can be altered because of changes in breast physiology or pathological state... 
Automatic exposure control and estimation of effective system noise in diffuse fluorescence tomographyDax L Kepshire
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755, USA
Opt Express 17:23272-83. 2009..This fluorophore has very low fluorescence yield, but high biological relevance for tumor imaging, given that it is produced in the mitochondria, and upregulated in many tumor types...- Early-photon fluorescence tomography: spatial resolution improvements and noise stability considerationsFrederic Leblond
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover New Hampshire 03755, USA
J Opt Soc Am A Opt Image Sci Vis 26:1444-57. 2009..5 to 2.5 mm) separated by less than 1.5 mm... - Implicit and explicit prior information in near-infrared spectral imaging: accuracy, quantification and diagnostic valueBrian W Pogue
Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
Philos Transact A Math Phys Eng Sci 369:4531-57. 2011..Most beneficial inclusion of prior information has been in the inversion/reconstruction process, because it solves the mathematical intractability. However, it is not clear that this is always the most beneficial stage... - Electrical impedance tomography of human brain function using reconstruction algorithms based on the finite element methodAndrew P Bagshaw
Department of Clinical Neurophysiology, University College London, UK
Neuroimage 20:752-64. 2003.... - Spectrally resolved bioluminescence optical tomographyHamid Dehghani
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 31:365-7. 2006..The location of the internal bioluminescence is obtained with 1 mm accuracy. Further, the amplitude of the reconstructed source is proportional to the actual bioluminescence intensity... - Weight-matrix structured regularization provides optimal generalized least-squares estimate in diffuse optical tomographyPhaneendra K Yalavarthy
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Med Phys 34:2085-98. 2007.... - Multiple-gate time domain diffuse fluorescence tomography allows more sparse tissue sampling without compromising image qualityRobert W Holt
Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755, USA
Opt Lett 37:2559-61. 2012.... - Near-infrared imaging in the small animal brain: optimization of fiber positionsHeng Xu
Dartmouth College, Thayer School of Engineering, Hanover, New Hampshire 03755, USA
J Biomed Opt 8:102-10. 2003..Practical space limitation considerations favor the one-sided fiber array geometry in the case where the NIR acquisition is expected to occur simultaneously with MRI... - A novel data calibration scheme for electrical impedance tomographyNirmal K Soni
Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755 8000, USA
Physiol Meas 24:421-35. 2003.... - Diffuse optical imagingAdam Gibson
Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT, UK
Philos Transact A Math Phys Eng Sci 367:3055-72. 2009..We aim to review the state of the art of optical imaging... - Optical tomography of a realistic neonatal head phantomAdam Gibson
Department of Medical Physics and Bioengineering, University College London, 11 20 Capper Street, London WC1E 6JA
Appl Opt 42:3109-16. 2003..The head-shaped mesh performed slightly better than the spherical mesh, particularly when the absorption of the central region of the phantom was increased... - Time resolved optical tomography of the human forearmE M Hillman
Department of Medical Physics and Bioengineering, University College London, UK
Phys Med Biol 46:1117-30. 2001.... - Contrast-detail analysis characterizing diffuse optical fluorescence tomography image reconstructionScott C Davis
J Biomed Opt 10:050501. 2005..Contrast-detail analysis using human detection of lower contrast limits provides fundamentally important information about the performance of reconstruction algorithms, and can be used to compare imaging performance of different systems... - Finite element implementation of Maxwell's equations for image reconstruction in electrical impedance tomographyNirmal K Soni
Philips Medical Systems, Cleveland, OH 44143, USA
IEEE Trans Med Imaging 25:55-61. 2006..The results show that scalar/vector potential reconstruction produces images which are essentially indistinguishable from a Laplace algorithm for frequencies below 1 MHz but superior at frequencies reaching 10 MHz... - Numerical modelling errors in electrical impedance tomographyHamid Dehghani
School of Physics, University of Exeter, UK
Physiol Meas 28:S45-55. 2007.... - Endoscopic, rapid near-infrared optical tomographyDaqing Piao
School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma, USA
Opt Lett 31:2876-8. 2006..This novel approach provides the key feasibility studies to allow this blood-based contrast imaging technology to be attempted in detection of cancer in internal organs via endoscopic interrogation... - Retinotopic mapping of adult human visual cortex with high-density diffuse optical tomographyBenjamin W Zeff
Department of Radiology, Washington University School of Medicine, St Louis, MO 63110, USA
Proc Natl Acad Sci U S A 104:12169-74. 2007..These results demonstrate that high-density DOT is a practical and powerful tool for mapping function in the human cortex...