Prof. Magda O. El-Shenawee Profile

Prof. Magda O. El-Shenawee

Professor at Univ of Arkansas

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Publications (21)

SPIE Journal Paper | 5 December 2024 Open Access

Polarimetry terahertz imaging of human breast cancer surgical specimens

Nikita Gurjar, Keith Bailey, Magda El-Shenawee

JMI, Vol. 11, Issue 06, 065503, (December 2024) https://doi.org/10.1117/12.10.1117/1.JMI.11.6.065503

KEYWORDS: Tissues, Terahertz radiation, Biological samples, Polarization, Pathology, Cancer, Polarimetry, Tumors, Breast, Mueller matrices

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PurposeWe investigate terahertz (THz) polarimetry imaging of seven human breast cancer surgical specimens. The goal is to enhance image contrast between adjacent tissue types of cancer, healthy collagen, and fat in excised breast tumors. Based on the biological perception of random growth of cancer and invasion of surrounding healthy tissues in the breast, we hypothesize that cancerous cells interact with the THz electric field in a different manner compared with healthy cells. This difference can be best captured using multiple polarizations instead of single polarization.ApproachTime domain pulsed signals are experimentally collected from each pixel of the specimen in horizontal–horizontal, vertical–horizontal, vertical–vertical, and horizontal–vertical polarizations. The time domain pulses are transformed to the frequency domain to obtain the power spectra and 16 Mueller matrix images. The whole-slide pathology imaging was used to interpret and label all images.ResultsThe results of the cross and co-polarization power spectrum images demonstrated a strong dependency on the tissue orientation with respect to the emitted and detected electric fields. At the 130-deg rotation angle of the scanned samples, the detector showed the strongest reflected signal in cross-polarization. Furthermore, the Mueller matrix images consistently demonstrated patterns in fresh and block tissues confirming the differentiation between tissue types in breast tumor specimens.ConclusionsTHz polarimetry imaging shows a potential for improving image contrast in excised tumor tissues compared with single polarization imaging. Cross-polarization signals demonstrated smaller amplitudes compared with co-polarized signals. However, averaging the signal during measurements has tremendously improved the image. Furthermore, in post-processing, averaging the frequency domain images and the Mueller matrix elements with respect to frequency has led to better image contrast. Some patterns in the Mueller matrix images were difficult to interpret leading to the necessity of more investigation of the Mueller matrix and its physiological interpretation of breast tumor tissues.

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SPIE Journal Paper | 12 January 2022

Hyperspectral terahertz imaging and optical clearance for cancer classification in breast tumor surgical specimen

Nagma Vohra, Haoyan Liu, Alexander H. Nelson, Keith Bailey, Magda El-Shenawee

JMI, Vol. 9, Issue 01, 014002, (January 2022) https://doi.org/10.1117/12.10.1117/1.JMI.9.1.014002

KEYWORDS: Tissues, Terahertz radiation, Cancer, Tumors, Pathology, Collagen, Hyperspectral imaging, Absorption, Breast, Image classification

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Purpose: We investigate the enhancement in terahertz (THz) images of freshly excised breast tumors upon treatment with an optical clearance agent. The hyperspectral imaging and spectral classifications are used to quantitatively demonstrate the image enhancement. Glycerol solution with 60% concentration is applied to excised breast tumor specimens for various time durations to investigate the effectiveness on image enhancement. Approach: THz reflection spectroscopy is utilized to obtain the absorption coefficient and the index of refraction of untreated and glycerol-treated tissues at each frequency up to 3 THz. Two classifiers, spectral angular mapping (SAM) based on several kernels and Euclidean minimum distance (EMD) are implemented to evaluate the effectiveness of the treatment. The testing raw data is obtained from five breast cancer specimens: two untreated specimens and three specimens treated with glycerol solution for 20, 40, or 60 min. All tumors used in the testing data have healthy tissues adjacent to cancerous ones consistent with the challenge faced in lumpectomy surgeries. Results: The glycerol-treated tissues showed a decrease in the absorption coefficients compared with untreated tissues, especially as the period of treatment increased. Although the sensitivity metric of the classifier presented higher values in the untreated tissues compared with the treated ones, the specificity and accuracy metrics demonstrated higher values for the treated tissues compared with the untreated ones. Conclusions: The biocompatible glycerol solution is a potential optical clearance agent in THz imaging while keeping the histopathology imaging intact. The SAM technique provided a good classification of cancerous tissues despite the small amount of cancer in the training data (only 7%). The SAM exponential kernel and EMD presented classification accuracy of ∼80 % to 85% compared with linear and polynomial kernels that provided accuracy ranging from 70% to 80%. Overall, glycerol treatment provides a potential improvement in cancer classification in freshly excised breast tumors.

SPIE Journal Paper | 26 April 2021 Open Access

Mammary tumors in Sprague Dawley rats induced by N-ethyl-N-nitrosourea for evaluating terahertz imaging of breast cancer

Nagma Vohra, Tanny Chavez, Joel Troncoso, Narasimhan Rajaram, Jingxian Wu, Patricia Coan, Todd Jackson, Keith Bailey, Magda El-Shenawee

JMI, Vol. 8, Issue 02, 023504, (April 2021) https://doi.org/10.1117/12.10.1117/1.JMI.8.2.023504

KEYWORDS: Tumors, Tissues, Terahertz radiation, Cancer, Pathology, Expectation maximization algorithms, Image segmentation, Tumor growth modeling, Breast cancer, Breast

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SPIE Journal Paper | 14 May 2019

Terahertz tomographic imaging of freshly excised human breast tissues

Tyler Bowman, Nagma Vohra, Keith Bailey, Magda El-Shenawee

JMI, Vol. 6, Issue 02, 023501, (May 2019) https://doi.org/10.1117/12.10.1117/1.JMI.6.2.023501

KEYWORDS: Tissues, Terahertz radiation, Cancer, Collagen, Imaging spectroscopy, Breast, Spectroscopy, Absorption, Refractive index, Reflection

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SPIE Journal Paper | 14 February 2018 Open Access

Pulsed terahertz imaging of breast cancer in freshly excised murine tumors

Tyler Bowman, Tanny Chavez, Kamrul Khan, Jingxian Wu, Avishek Chakraborty, Narasimhan Rajaram, Keith Bailey, Magda El-Shenawee

JBO, Vol. 23, Issue 02, 026004, (February 2018) https://doi.org/10.1117/12.10.1117/1.JBO.23.2.026004

KEYWORDS: Tissues, Pathology, Cancer, Terahertz radiation, Tumors, Image classification, Breast cancer, Statistical modeling, Millimeter wave imaging, Statistical analysis

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SPIE Journal Paper | 24 January 2017 Open Access

Review of terahertz photoconductive antenna technology

Nathan Burford, Magda El-Shenawee

OE, Vol. 56, Issue 01, 010901, (January 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.1.010901

KEYWORDS: Terahertz radiation, Principal component analysis, Antennas, Electrodes, Gallium arsenide, Terahertz technology, Plasmonics, Nanostructures, Signal to noise ratio, Sensors

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Proceedings Article | 18 March 2016 Presentation + Paper

Margin assessment of three-dimensional breast cancer phantoms using terahertz imaging

Tyler Bowman, Alec Walter, Magda El-Shenawee

Proceedings Volume 9700, 97000J (2016) https://doi.org/10.1117/12.2212671

KEYWORDS: Breast cancer, Tissues, Millimeter wave imaging, Cancer, 3D image processing, Optical phantoms, Terahertz radiation, Reflection, Tumors, Tumor growth modeling

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Proceedings Article | 18 March 2016 Presentation + Paper

Development of breast cancer tissue phantoms for terahertz imaging

Alec Walter, Tyler Bowman, Magda El-Shenawee

Proceedings Volume 9700, 970003 (2016) https://doi.org/10.1117/12.2211176

KEYWORDS: Tissues, Breast, Breast cancer, Refractive index, Absorption, Spectroscopy, Terahertz spectroscopy, Cancer, Water, Terahertz radiation, Optical properties, Tissue optics, Tumors, Solids

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Proceedings Article | 7 March 2016 Presentation + Paper

Adaptive enhancement and visualization techniques for 3D THz images of breast cancer tumors

Yuhao Wu, Tyler Bowman, John Gauch, Magda El-Shenawee

Proceedings Volume 9706, 970602 (2016) https://doi.org/10.1117/12.2209706

KEYWORDS: Terahertz radiation, Tissues, Visualization, Image enhancement, Image processing, Image segmentation, 3D image enhancement, 3D image processing, Cancer, Image visualization, Tumors, Breast cancer, Breast, Image filtering

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Proceedings Article | 7 March 2016 Paper

Regional spectroscopy of paraffin-embedded breast cancer tissue using pulsed terahertz transmission imaging

Tyler Bowman, Magda El-Shenawee, Lucas Campbell

Proceedings Volume 9706, 97061W (2016) https://doi.org/10.1117/12.2212704

KEYWORDS: Imaging spectroscopy, Spectroscopy, Tissues, Breast cancer, Tissue optics, Terahertz spectroscopy, Cancer, Terahertz radiation, Absorption, Refractive index

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Proceedings Article | 7 March 2016 Paper

Time of flight estimation for breast cancer margin thickness using embedded tumors

Tyler Bowman, Magda El-Shenawee, Lucas Campbell

Proceedings Volume 9706, 97061V (2016) https://doi.org/10.1117/12.2211167

KEYWORDS: Breast cancer, Millimeter wave imaging, Imaging systems, 3D image processing, Analytical research, Terahertz sources, Biological research, Reflection, Natural surfaces, Cancer, Tumors, Tissue optics, Terahertz radiation, Pathology

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Proceedings Article | 25 February 2016 Paper

Simulation, fabrication, and measurement of a plasmonic-enhanced terahertz photoconductive antenna

Nathan Burford, Magda El-Shenawee

Proceedings Volume 9747, 974704 (2016) https://doi.org/10.1117/12.2217852

KEYWORDS: Terahertz radiation, Antennas, Gallium arsenide, Plasmonics, Principal component analysis, Thin films, Pyroelectric detectors, Thermography, Electrodes, Photons

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Proceedings Article | 21 May 2004 Paper

Computational algorithm for reconstructing the profile of 2D rough surfaces

Magda El-Shenawee, Eric Miller

Proceedings Volume 5299, (2004) https://doi.org/10.1117/12.529306

KEYWORDS: Reconstruction algorithms, Receivers, Algorithm development, Dielectrics, Detection and tracking algorithms, General packet radio service, Electromagnetic radiation, Optimization (mathematics), Dielectric polarization, Radar signal processing

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Proceedings Article | 11 September 2003 Paper

Scattering from dielectric targets buried beneath 2D randomly rough surfaces

Magda El-Shenawee, Carey Rappaport, Eric Miller

Proceedings Volume 5089, (2003) https://doi.org/10.1117/12.486752

KEYWORDS: Scattering, Dielectrics, Polarimetry, 3D acquisition, Monte Carlo methods, Land mines, Dielectric polarization, Target detection, Free space, Electrical engineering

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Proceedings Article | 11 September 2003 Paper

Covariance matrix for radar imaging of targets buried beneath two-dimensional rough surfaces

Magda El-Shenawee, Eric Miller

Proceedings Volume 5089, (2003) https://doi.org/10.1117/12.488497

KEYWORDS: Radar, Target detection, Scattering, Radar imaging, Backscatter, Electromagnetic scattering, Dielectrics, Polarimetry, 3D acquisition, Electromagnetic radiation

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Proceedings Article | 13 August 2002 Paper

Parametric investigation of ground roughness on the interference between AP-mine and clutter-object buried under two-dimensional random rough surfaces

Magda El-Shenawee, Carey Rappaport

Proceedings Volume 4742, (2002) https://doi.org/10.1117/12.479103

KEYWORDS: Scattering, Electromagnetic scattering, Magnetism, Electromagnetism, Land mines, Mining, Dielectrics, Multiple scattering, Target detection, 3D modeling

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Proceedings Article | 13 August 2002 Paper

Hypothesis testing detection of mines buried under rough ground surfaces using 2D FDTD modeling

He Zhan, Carey Rappaport, Magda El-Shenawee, Eric Miller

Proceedings Volume 4742, (2002) https://doi.org/10.1117/12.479073

KEYWORDS: Finite-difference time-domain method, Signal processing, Target detection, Land mines, General packet radio service, Dielectrics, Reflection, Surface roughness, Receivers, Monte Carlo methods

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In ground penetrating radar (GPR) antipersonnel mine sensing, in which the target is small, shallow and often of low dielectric contrast, detection is challenging. One of the difficulties is that it is hard to distinguish the target signal from the omnipresent random rough ground reflection clutter. In this work, a Monte Carlo computational simulation using 2-dimensional (2-D) transverse magnetic (TM) finite difference time domain (FDTD) with multiple rough surfaces is implemented to investigate single TNT target buries in dispersive soil. Based on the effects of the random rough surface on an impulse GPR signal and the knowledge of wave propagation differences in different media - air, soil, and TNT - a special background average process using physics based signal processing (PBSP) is performed to remove the ground clutter signal. This procedure first involves shifting and scaling multiple time signals from target-free random rough ground to establish the nominal (average) ground reflection pulse shape. Next, this nominal pulse shape is correlated in time with each trial signal, then shifted and scaled to match the ground surface clutter of that trial signal. Subtracting this shifted scaled clutter signal from the trial signal ideally leaves the target signal (with some additional multiple scattering between the target and ground surface). The PBSP algorithm reapplied in cases for which surface scattering occurs at multiple points. The statistical results of PBSP surface clutter removal indicate that the detection performance degrades with increasing surface roughness and decreasing burial depth. Hypothesis testing on the processed results proved to be successful in a detection and estimation point of view. This paper presents the detection performances in terms of Receiver Operating Characteristics (ROC) for various ground surface roughness and target burial depth cases. Also demonstrated is the performance improvements expected from multiple views: indicating that a multi-bistatic configuration appears to be superior to multistatic transmitter/receiver geometry with minimum combinations.

Proceedings Article | 13 August 2002 Paper

Scattering from multilayered random rough surfaces using the Steepest Descent Fast Multipole Method (SDFMM) and the multiple interaction model

Magda El-Shenawee

Proceedings Volume 4742, (2002) https://doi.org/10.1117/12.479075

KEYWORDS: Multiple scattering, Magnetism, Scattering, Multilayers, Interfaces, 3D modeling, Electromagnetic scattering, Optical spheres, Near field, Dielectrics

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Proceedings Article | 18 October 2001 Paper

Statistics of electromagnetic near fields scattered from 3D AP mines buried under random rough surface calculated using the steepest descent fast multipole method (SDFMM)

Magda El-Shenawee, Carey Rappaport

Proceedings Volume 4394, (2001) https://doi.org/10.1117/12.445504

KEYWORDS: Mining, Interfaces, Dielectrics, Near field, Scattering, Gaussian beams, Monte Carlo methods, Optical spheres, Electromagnetism, General packet radio service

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Proceedings Article | 22 August 2000 Paper

Quantifying the effects of different rough surface statistics for mine detection using the FDTD technique

Magda El-Shenawee, Carey Rappaport

Proceedings Volume 4038, (2000) https://doi.org/10.1117/12.396180

KEYWORDS: Composites, Monte Carlo methods, Finite-difference time-domain method, Land mines, Distortion, Surface roughness, Receivers, Transmitters, Correlation function, Fourier transforms

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Proceedings Article | 30 October 1998 Paper

High-frequency approximations of the full wave solutions to single and double scatter cross sections for two-dimensional random rough surfaces

Ezekiel Bahar, Magda El-Shenawee

Proceedings Volume 3426, (1998) https://doi.org/10.1117/12.328459

KEYWORDS: Backscatter, Scattering, Polarization, Radar, Electromagnetism, Receivers, Electro optics, Maxwell's equations, Geometrical optics, Numerical analysis

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The like and cross polarized single and double scattered fields are derived using a full wave approach. This approach is based on the complete expansion of the electromagnetic fields, the imposition of exact boundary conditions and the conversion of Maxwell's equations into generalized telegraphists equations for the scattered wave amplitudes. Thus, the zero order iterative solutions for the generalized telegraphists equations yield the primary electromagnetic (source) fields impressed upon the rough surface. The first and second order iterative solutions to the generalized telegropherts' equations yield the single and double scattered fields. This can be clearly demonstrated by taking the geometric optics limit of the full wave solutions. To obtain the corresponding like and cross polarized scatter cross sections, as in the case of scattering from one dimensional rough surfaces, it is necessary to account for contributions from the quasi parallel double scatter paths as well as the quasi antiparallel double scatter paths. However, for scattering from two dimensional rough surfaces, these paths are not restricted to the plane of incidence. The full wave solutions for the double scattered fields are expressed as six dimensional integrals, that account for the complete wave spectra of scattered fields and the coordinate variables at a pair of points on the rough surface. These expressions are used to obtain the multidimensional integrals for the like and cross polarized cross sections. To make these solutions tractable for computational purposes, a high frequency approximation of the full wave double scatter cross sections are expressed as four dimensional integrals involving scatter wave vector variables. These results can be evaluated in significantly less time than standard numerical solutions of the integral equations. Moreover, the physical interpretation of the results shed light on the impact, of different statistical parameters of the random rough surfaces, upon the backscatter enhancement.

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