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Glen Head, NY, United States

Flexman M.L.,Columbia University | Khalil M.A.,Columbia University | Abdi R.A.,New York University | Kim H.K.,Columbia University | And 6 more authors.
Journal of Biomedical Optics | Year: 2011

Diffuse optical tomography has shown promising results as a tool for breast cancer screening and monitoring response to chemotherapy. Dynamic imaging of the transient response of the breast to an external stimulus, such as pressure or a respiratory maneuver, can provide additional information that can be used to detect tumors. We present a new digital continuous-wave optical tomography system designed to simultaneously image both breasts at fast frame rates and with a large number of sources and detectors. The system uses a master-slave digital signal processor-based detection architecture to achieve a dynamic range of 160 dB and a frame rate of 1.7 Hz with 32 sources, 64 detectors, and 4 wavelengths per breast. Included is a preliminary study of one healthy patient and two breast cancer patients showing the ability to identify an invasive carcinoma based on the hemodynamic response to a breath hold. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Pflieger M.E.,Source Signal Imaging, Inc. | Barbour R.L.,SUNY Downstate Medical Center | Barbour R.L.,NIRx Medical Technologies LLC
Biomedical Optics, BIOMED 2012 | Year: 2012

Multimodal integration in the field of human brain mapping has evolved from structural-functional co-registrations toward functional-functional combinations. This paper briefly reviews fMRI-EEG, fMRI-NIRS, EEG-NIRS, and fMRI-EEG-NIRS combinations. © OSA 2012.

Piao D.,Oklahoma State University | Barbour R.L.,SUNY Downstate Medical Center | Barbour R.L.,NIRx Medical Technologies LLC | Graber H.L.,NIRx Medical Technologies LLC | Lee D.C.,University of Oklahoma
Novel Techniques in Microscopy, NTM 2015 | Year: 2015

We estimate analytically how much the differential pathlength factor for steady-state near-infrared spectroscopy of homogeneous medium varies when evaluated in geometries including sphere as applying to neonatal head, comparing to that in the semi-infinite half-space. © OSA 2015.

Piao D.,Oklahoma State University | Barbour R.L.,SUNY Downstate Medical Center | Barbour R.L.,NIRx Medical Technologies LLC | Graber H.L.,NIRx Medical Technologies LLC | Lee D.C.,University of Oklahoma
Journal of Biomedical Optics | Year: 2015

This work analytically examines some dependences of the differential pathlength factor (DPF) for steady-state photon diffusion in a homogeneous medium on the shape, dimension, and absorption and reduced scattering coefficients of the medium. The medium geometries considered include a semi-infinite geometry, an infinite-length cylinder evaluated along the azimuthal direction, and a sphere. Steady-state photon fluence rate in the cylinder and sphere geometries is represented by a form involving the physical source, its image with respect to the associated extrapolated half-plane, and a radius-dependent term, leading to simplified formula for estimating the DPFs. With the source-detector distance and medium optical properties held fixed across all three geometries, and equal radii for the cylinder and sphere, the DPF is the greatest in the semi-infinite and the smallest in the sphere geometry. When compared to the results from finite-element method, the DPFs analytically estimated for 10 to 25 mm source-detector separations on a sphere of 50 mm radius with μa = 0.01 mm-1 and μs′=1.0 mm-1 are on average less than 5% different. The approximation for sphere, generally valid for a diameter ≥20 times of the effective attenuation pathlength, may be useful for rapid estimation of DPFs in near-infrared spectroscopy of an infant head and for short source-detector separation. © The Authors 2015.

Graber H.L.,SUNY Downstate Medical Center | Graber H.L.,NIRx Medical Technologies LLC | Al abdi R.,Jordan University of Science and Technology | Xu Y.,SUNY Downstate Medical Center | And 9 more authors.
Medical Physics | Year: 2015

Purpose: The work presented here demonstrates an application of diffuse optical tomography (DOT) to the problem of breast-cancer diagnosis. The potential for using spatial and temporal variability measures of the hemoglobin signal to identify useful biomarkers was studied. Methods: DOT imaging data were collected using two instrumentation platforms the authors developed, which were suitable for exploring tissue dynamics while performing a simultaneous bilateral exam. For each component of the hemoglobin signal (e.g., total, oxygenated), the image time series was reduced to eight scalar metrics that were affected by one or more dynamic properties of the breast microvasculature (e.g., average amplitude, amplitude heterogeneity, strength of spatial coordination). Receiver-operator characteristic (ROC) analyses, comparing groups of subjects with breast cancer to various control groups (i.e., all noncancer subjects, only those with diagnosed benign breast pathology, and only those with no known breast pathology), were performed to evaluate the effect of cancer on the magnitudes of the metrics and of their interbreast differences and ratios. Results: For women with known breast cancer, simultaneous bilateral DOT breast measures reveal a marked increase in the resting-state amplitude of the vasomotor response in the hemoglobin signal for the affected breast, compared to the contralateral, noncancer breast. Reconstructed 3D spatial maps of observed dynamics also show that this behavior extends well beyond the tumor border. In an effort to identify biomarkers that have the potential to support clinical aims, a group of scalar quantities extracted from the time series measures was systematically examined. This analysis showed that many of the quantities obtained by computing paired responses from the bilateral scans (e.g., interbreast differences, ratios) reveal statistically significant differences between the cancer-positive and -negative subject groups, while the corresponding measures derived from individual breast scans do not. ROC analyses yield area-under-curve values in the 77% 87% range, depending on the metric, with sensitivity and specificity values ranging from 66% to 91%. An interesting result is the initially unexpected finding that the hemodynamic-image metrics are only weakly dependent on the tumor burden, implying that the DOT technique employed is sensitive to tumor-induced changes in the vascular dynamics of the surrounding breast tissue as well. Computational modeling studies serve to identify which properties of the vasomotor response (e.g., average amplitude, amplitude heterogeneity, and phase heterogeneity) principally determine the values of the metrics and their codependences. Findings from the modeling studies also serve to clarify the influence of spatial-response heterogeneity and of system-design limitations, and they reveal the impact that a complex dependence of metric values on the modeled behaviors has on the success in distinguishing between cancer-positive and -negative subjects. Conclusions: The authors identified promising hemoglobin-based biomarkers for breast cancer from measures of the resting-state dynamics of the vascular bed. A notable feature of these biomarkers is that their spatial extent encompasses a large fraction of the breast volume, which is mainly independent of tumor size. Tumor-induced induction of nitric oxide synthesis, a well-established concomitant of many breast cancers, is offered as a plausible biological causal factor for the reported findings. © 2015 American Association of Physicists in Medicine.

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