Engineering Commons^™

Detecting The Presence Of Electronic Devices In Smart Homes Using Harmonic Radar, Beatrice Perez, Gregory Mazzaro, Timothy J. Pierson, David Kotz

Dartmouth Scholarship

Data about users is collected constantly by phones, cameras, Internet websites, and others. The advent of so-called ‘Smart Things' now enable ever-more sensitive data to be collected inside that most private of spaces: the home. The first step in helping users regain control of their information (inside their home) is to alert them to the presence of potentially unwanted electronics. In this paper, we present a system that could help homeowners (or home dwellers) find electronic devices in their living space. Specifically, we demonstrate the use of harmonic radars (sometimes called nonlinear junction detectors), which have also been used in …

Using Natural Language Processing And Sentiment Analysis To Augment Traditional User-Centered Design: Development And Usability Study, Curtis L. Petersen, Ryan Halter, David Kotz, Lorie Loeb, Summer B. Cook, Dawna M. Pidgeon, Brock Christensen, John A. Batsis

Dartmouth Scholarship

Background: Sarcopenia, defined as the age-associated loss of muscle mass and strength, can be effectively mitigated through resistance-based physical activity. With compliance at approximately 40% for home-based exercise prescriptions, implementing a remote sensing system would help patients and clinicians to better understand treatment progress and increase compliance. The inclusion of end users in the development of mobile apps for remote-sensing systems can ensure that they are both user friendly and facilitate compliance. With advancements in natural language processing (NLP), there is potential for these methods to be used with data collected through the user-centered design process.

Objective: This study aims …

1/Fnoise Modelling And Characterization For Cmos Quanta Image Sensors, Wei Deng, Eric R. Fossum

Dartmouth Scholarship

This work fits the measured in-pixel source-follower noise in a CMOS Quanta Image Sensor (QIS) prototype chip using physics-based 1/f noise models, rather than the widely-used fitting model for analog designers. This paper discusses the different origins of 1/f noise in QIS devices and includes correlated double sampling (CDS). The modelling results based on the Hooge mobility fluctuation, which uses one adjustable parameter, match the experimental measurements, including the variation in noise from room temperature to –70 °C. This work provides useful information for the implementation of QIS in scientific applications and suggests that even lower read noise is attainable …

Biomedical Engineering Or Biomedical Optics: Will The Real Discipline Please Stand Up?, Brian W. Pogue

Dartmouth Scholarship

This editorial reflects on the shape of biomedical engineering as a discipline, and its relation to biomedical optics.

Characterizing Short-Wave Infrared Fluorescence Of Conventional Near-Infrared Fluorophores, Brook K. Byrd, Margaret R. Folaron, Joseph P. Leonor, Rendall R. Strawbridge, Xu Cao, Petr Bruza, Scott C. Davis

Dartmouth Scholarship

The observed behavior of short-wave infrared (SWIR) light in tissue, characterized by relatively low scatter and subdiffuse photon transport, has generated considerable interest for the potential of SWIR imaging to produce high-resolution, subsurface images of fluorescence activity in vivo. These properties have important implications for fluorescence-guided surgery and preclinical biomedical research. Until recently, translational efforts have been impeded by the conventional understanding that fluorescence molecular imaging in the SWIR regime requires custom molecular probes that do not yet have proven safety profiles in humans. However, recent studies have shown that two readily available near-infrared (NIR-I) fluorophores produce measurable SWIR fluorescence, …

Diagnostic Performance Of Receptor-Specific Surgical Specimen Staining Correlates With Receptor Expression Level, Jasmin M. Schaefer, Connor W. Barth, Scott C. Davis, Summer L. Gibbs

Dartmouth Scholarship

Intraoperative margin assessment is imperative to cancer cure but is a continued challenge to successful surgery. Breast conserving surgery is a relevant example, where a cosmetically improved outcome is gained over mastectomy, but re-excision is required in >25  %   of cases due to positive or closely involved margins. Clinical translation of margin assessment modalities that must directly contact the patient or required administered contrast agents are time consuming and costly to move from bench to bedside. Tumor resections provide a unique surgical opportunity to deploy margin assessment technologies including contrast agents on the resected tissues, substantially shortening the path to …

Ensuring Scientific Publishing Credibility In Translational Biomedical Optics., Brian W. Pogue

Dartmouth Scholarship

Optics has consistently been the largest singular technology sector used in medicine, and major advances in biomedical optics are documented daily in peer-reviewed publications. However, the academic stature of this field can be damaged by weaknesses in scientific publishing, where a “credibility crisis” has emerged as a popularized and increasingly studied dialogue. While there are still relatively few overt cases of fraud or erroneous research, more insidious aspects are seen in papers with results that have either low statistical power, selective reporting of observations, or data or computer codes that cannot be independently verified. Interestingly, the same solutions that improve …

Novel Materials Can Radically Improve Whole-System Environmental Impacts Of Additive Manufacturing, Jeremy Faludi, Cory M. Van Sice, Yuan Shi, Justin Bower, Owen M.K Brooks

Dartmouth Scholarship

Additive manufacturing often has higher environmental impacts per part than traditional manufacturing at scale, but new materials can enable more sustainable 3D printing. This study developed and tested novel materials for paste extrusion printing, and tested materials invented by others. Testing compared their whole-system environmental impacts to standard ABS extrusion, measured by life cycle assessment (LCA); testing also assessed material strength, printability, and cost. Materials were chosen for low print energy (chemical bonding, not melting), low toxicity, and circular life cycle (biodegradable, ideally sourced from waste biomaterial). Printing energy was reduced 75% (from 160 to 40 Wh/part), and embodied impacts …

Cherenkov Excited Short-Wavelength Infrared Fluorescence Imaging In Vivo With External Beam Radiation, Xu Cao, Shudong Jiang, Mengyu Jeremy Jia, Jason R. Gunn, Tianshun Miao, Scott C. Davis, Petr Bruza, Brian W. Pogue

Dartmouth Scholarship

Cherenkov emission induced by external beam radiation therapy from a clinical linear accelerator (LINAC) can be used to excite phosphors deep in biological tissues. As with all luminescence imaging, there is a desire to minimize the spectral overlap between the excitation light and emission wavelengths, here between the Cherenkov and the phosphor. Cherenkov excited short-wavelength infrared (SWIR, 1000 to 1700 nm) fluorescence imaging has been demonstrated for the first time, using long Stokes-shift fluorophore PdSe quantum dots (QD) with nanosecond lifetime and an optimized SWIR detection. The 1  /  λ2 intensity spectrum characteristic of Cherenkov emission leads to low overlap …

Review Of Methods For Intraoperative Margin Detection For Breast Conserving Surgery, Benjamin W. Maloney, David M. Mcclatchy, Brian W. Pogue, Keith D. Paulsen, Wendy A. Wells, Richard J. Barth

Dartmouth Scholarship

Breast conserving surgery (BCS) is an effective treatment for early-stage cancers as long as the margins of the resected tissue are free of disease according to consensus guidelines for patient management. However, 15% to 35% of patients undergo a second surgery since malignant cells are found close to or at the margins of the original resection specimen. This review highlights imaging approaches being investigated to reduce the rate of positive margins, and they are reviewed with the assumption that a new system would need high sensitivity near 95% and specificity near 85%. The problem appears to be twofold. The first …

Optical And X-Ray Technology Synergies Enabling Diagnostic And Therapeutic Applications In Medicine, Brian W. Pogue, Brian C. Wilson

Dartmouth Scholarship

X-ray and optical technologies are the two central pillars for human imaging and therapy. The strengths of x-rays are deep tissue penetration, effective cytotoxicity, and the ability to image with robust projection and computed-tomography methods. The major limitations of x-ray use are the lack of molecular specificity and the carcinogenic risk. In comparison, optical interactions with tissue are strongly scatter dominated, leading to limited tissue penetration, making imaging and therapy largely restricted to superficial or endoscopically directed tissues. However, optical photon energies are comparable with molecular energy levels, thereby providing the strength of intrinsic molecular specificity. Additionally, optical technologies are …

Tissue Oxygen Saturation Predicts Response To Breast Cancer Neoadjuvant Chemotherapy Within 10 Days Of Treatment, Jeffrey M. Cochran, David R. Busch, Anais Leproux, Zheng Zhang, Thomas D. O'Sullivan, Albert E. Cerussi, Philip M. Carpenter, Rita S. Mehta, Darren Roblyer, Wei Yang, Keith D. Paulsen, Brian Pogue, Shudong Jiang, Peter A. Kaufman

Dartmouth Scholarship

Ideally, neoadjuvant chemotherapy (NAC) assessment should predict pathologic complete response (pCR), a surrogate clinical endpoint for 5-year survival, as early as possible during typical 3- to 6-month breast cancer treatments. We introduce and demonstrate an approach for predicting pCR within 10 days of initiating NAC. The method uses a bedside diffuse optical spectroscopic imaging (DOSI) technology and logistic regression modeling. Tumor and normal tissue physiological properties were measured longitudinally throughout the course of NAC in 33 patients enrolled in the American College of Radiology Imaging Network multicenter breast cancer DOSI trial (ACRIN-6691). An image analysis scheme, employing z-score normalization to …

Perspective Review Of What Is Needed For Molecular-Specific Fluorescence-Guided Surgery, Brian W. Pogue, Eben L. Rosenthal, Samuel Achilefu, Gooitzen M. Van Dam

Dartmouth Scholarship

Molecular image-guided surgery has the potential for translating the tools of molecular pathology to real-time guidance in surgery. As a whole, there are incredibly positive indicators of growth, including the first United States Food and Drug Administration clearance of an enzyme-biosynthetic-activated probe for surgery guidance, and a growing number of companies producing agents and imaging systems. The strengths and opportunities must be continued but are hampered by important weaknesses and threats within the field. A key issue to solve is the inability of macroscopic imaging tools to resolve microscopic biological disease heterogeneity and the limitations in microscopic systems matching surgery …

Indutivo: Contact-Based, Object-Driven Interactions With Inductive Sensing, Jun Gong, Xin Yang, Teddy Seyed, Josh Urban Davis, Xing-Dong Yang

Dartmouth Scholarship

We present Indutivo, a contact-based inductive sensing technique for contextual interactions. Our technique recognizes conductive objects (metallic primarily) that are commonly found in households and daily environments, as well as their individual movements when placed against the sensor. These movements include sliding, hinging, and rotation. We describe our sensing principle and how we designed the size, shape, and layout of our sensor coils to optimize sensitivity, sensing range, recognition and tracking accuracy. Through several studies, we also demonstrated the performance of our proposed sensing technique in environments with varying levels of noise and interference conditions. We conclude by presenting demo …

Phasorsec: Protocol Security Filters For Wide Area Measurement Systems, Prashant Anantharaman, Kartik Palani, Rafael Brantley, Sergey Bratus, Sean W. Smith

Dartmouth Scholarship

The addition of synchrophasors to the power grid to improve observability comes at the cost of an increased attack surface: the wide area measurement system. A common source of zero-days, that can be used to exploit the system, is improper input validation. The strict availability and timing requirements of the grid make it critical that input validation be done right and in a timely fashion. PhasorSec is a hardened security filter for the synchrophasor communication protocol, C37.118. PhasorSec is built using language theoretic principles which treat all input as a language with a specific grammar that defines what input must …

Battery-Free Eye Tracker On Glasses, Tianxing Li, Xia Zhou

Dartmouth Scholarship

This paper presents a battery-free wearable eye tracker that tracks both the 2D position and diameter of a pupil based on its light absorption property. With a few near-infrared (NIR) lights and photodiodes around the eye, NIR lights sequentially illuminate the eye from various directions while photodiodes sense spatial patterns of reflected light, which are used to infer pupil’s position and diameter on the fly via a lightweight inference algorithm. The system also exploits characteristics of different eye movement stages and adjusts its sensing and computation accordingly for further energy savings. A prototype is built with off-the-shelf hardware components and …

Light Scattering Measured With Spatial Frequency Domain Imaging Can Predict Stromal Versus Epithelial Proportions In Surgically Resected Breast Tissue, David M. Mcclatchy, Elizabeth J. Rizzo, Wendy A. Wells, Candice C. Black, Keith D. Paulsen, Stephen C. Kanick, Brian W. Pogue

Dartmouth Scholarship

This study aims to determine if light scatter parameters measured with spatial frequency domain imaging (SFDI) can accurately predict stromal, epithelial, and adipose fractions in freshly resected, unstained human breast specimens. An explicit model was developed to predict stromal, epithelial, and adipose fractions as a function of light scattering parameters, which was validated against a quantitative analysis of digitized histology slides for N  =  31 specimens using leave-one-out cross-fold validation. Specimen mean stromal, epithelial, and adipose volume fractions predicted from light scattering parameters strongly correlated with those calculated from digitized histology slides (r  =  0.90, 0.77, and 0.91, respectively, p-value× …

Quantifying Cancer Cell Receptors With Paired-Agent Fluorescent Imaging: A Novel Method To Account For Tissue Optical Property Effects., Negar Sadeghipour, Scott C. Davis, Kenneth M. Tichauer

Dartmouth Scholarship

Dynamic fluorescence imaging approaches can be used to estimate the concentration of cell surface receptorsin vivo. Kinetic models are used to generate the final estimation by taking the targeted imaging agent concentration as a function of time. However, tissue absorption and scattering properties cause the final readout signal to be on a different scale than the real fluorescent agent concentration. In paired-agent imaging approaches, simultaneous injection of a suitable control imaging agent with a targeted one can account for non-specific uptake and retention of the targeted agent. Additionally, the signal from the control agent can be a normalizing …

Grant Funding Needs Parallel The Start-Up Venture: An Analogy For Translational Research Success, Brian W. Pogue

Dartmouth Scholarship

This editorial offers some ways to think about how best to position a research group for funding, by examining the parallels between what is needed for translational grants versus industry start-ups.

Multi-Beam Scan Analysis With A Clinical Linac For High Resolution Cherenkov-Excited Molecular Luminescence Imaging In Tissue., Mengyu Jeremy Jia, Peter Bruza, Lesley A. Jarvis, David J. Gladstone, Brian W. Pogue

Dartmouth Scholarship

Cherenkov-excited luminescence scanned imaging (CELSI) is achieved with external beam radiotherapy to map out molecular luminescence intensity or lifetime in tissue. Just as in fluorescence microscopy, the choice of excitation geometry can affect the imaging time, spatial resolution and contrast recovered. In this study, the use of spatially patterned illumination was systematically studied comparing scan shapes, starting with line scan and block patterns and increasing from single beams to multiple parallel beams and then to clinically used treatment plans for radiation therapy. The image recovery was improved by a spatial-temporal modulation-demodulation method, which used the ability to capture simultaneous images …

Weighting Function Effects In A Direct Regularization Method For Image-Guided Near-Infrared Spectral Tomography Of Breast Cancer., Jinchao Feng, Shudong Jiang, Brian W. Pogue, Keith Paulsen

Dartmouth Scholarship

Structural image-guided near-infrared spectral tomography (NIRST) has been developed as a way to use diffuse NIR spectroscopy within the context of image-guided quantification of tissue spectral features. A direct regularization imaging (DRI) method for NIRST has the value of not requiring any image segmentation. Here, we present a comprehensive investigational study to analyze the impact of the weighting function implied when weighting the recovery of optical coefficients in DRI based NIRST. This was done using simulations, phantom and clinical patient exam data. Simulations where the true object is known indicate that changes to this weighting function can vary the contrast …

Correcting For Targeted And Control Agent Signal Differences In Paired-Agent Molecular Imaging Of Cancer Cell-Surface Receptors, Negar Sadeghipour, Scott C. Davis, Kenneth M. Tichauer

Dartmouth Scholarship

Paired-agent kinetic modeling protocols provide one means of estimating cancer cell-surface receptors with in vivo molecular imaging. The protocols employ the coadministration of a control imaging agent with one or more targeted imaging agent to account for the nonspecific uptake and retention of the targeted agent. These methods require the targeted and control agent data be converted to equivalent units of concentration, typically requiring specialized equipment and calibration, and/or complex algorithms that raise the barrier to adoption. This work evaluates a kinetic model capable of correcting for targeted and control agent signal differences. This approach was compared with an existing …

Medical Perspective Articles To Stimulate The Field For Needs-Finding, Brian W. Pogue

Dartmouth Scholarship

This editorial by the journal's Editor in Chief, Brian Pogue, explains the need for a new type of paper.

Radiotherapy-Induced Cherenkov Luminescence Imaging In A Human Body Phantom, Syed Rakin Ahmed, Mengyu Jia, Petr Bruza, Sergei A. Vinogradov, Shudong Jiang, David J. Gladstone, Lesley A. Jarvis, Brian W. Pogue

Dartmouth Scholarship

Radiation therapy produces Cherenkov optical emission in tissue, and this light can be utilized to activate molecular probes. The feasibility of sensing luminescence from a tissue molecular oxygen sensor from within a human body phantom was examined using the geometry of the axillary lymph node region. Detection of regions down to 30-mm deep was feasible with submillimeter spatial resolution with the total quantity of the phosphorescent sensor PtG4 near 1 nanomole. Radiation sheet scanning in an epi-illumination geometry provided optimal coverage, and maximum intensity projection images provided illustration of the concept. This work provides the preliminary information needed to attempt …

Optimal Wavelength Selection For Optical Spectroscopy Of Hemoglobin And Water Within A Simulated Light-Scattering Tissue, Mikael Marois, Stephen L. Jacques, Keith D. Paulsen

Dartmouth Scholarship

An algorithm that selects optimal wavelengths for spectral fitting of diffuse light reflectance spectra using a nonnegative least squares method is presented. Oxyhemoglobin, deoxyhemoglobin, and water are considered representative absorbers, but the approach is not constrained or limited by absorber selection provided native basis spectra are available. The method removes wavelengths iteratively from a scattering-modulated absorption matrix by maximizing the product of its singular values and offers considerable improvements over previously published wavelength selection schemes. Resulting wavelength selections are valid for a broad range of optical properties and yield lower RMS errors than other wavelength combinations. The method is easily …

Biomedical Optics Scientific Community, Brian W. Pogue

Dartmouth Scholarship

The new Editor-in-Chief, Brian Pogue, gives an overview of the biomedical optics community.

Development And Evaluation Of A Connective Tissue Phantom Model For Subsurface Visualization Of Cancers Requiring Wide Local Excision, Kimberly S. Samkoe, Brent D. Bates, Niki N. Tselepidakis, Alisha V. Dsouza, Jason R. Gunn, Dipak B. Ramkumar, Keith D. Paulsen, Brian W. Pogue, Eric R. Henderson

Dartmouth Scholarship

Wide local excision (WLE) of tumors with negative margins remains a challenge because surgeons cannot directly visualize the mass. Fluorescence-guided surgery (FGS) may improve surgical accuracy; however, conventional methods with direct surface tumor visualization are not immediately applicable, and properties of tissues surrounding the cancer must be considered. We developed a phantom model for sarcoma resection with the near-infrared fluorophore IRDye 800CW and used it to iteratively define the properties of connective tissues that typically surround sarcoma tumors. We then tested the ability of a blinded surgeon to resect fluorescent tumor-simulating inclusions with ∼1-cm margins using predetermined target fluorescence intensities …

Both Adhe And A Separate Nadph-Dependent Alcohol Dehydrogenase Gene, Adha, Are Necessary For High Ethanol Production In Thermoanaerobacterium Saccharolyticum, Tianyong Zheng, Daniel G. Olson, Sean J. Murphy, Xiongjun Shao, Liang Tian, Lee Lynd

Dartmouth Scholarship

Thermoanaerobacterium saccharolyticum has been engineered to produce ethanol at ∼90% theoretical yield and titer of 70 g/L. Its ethanol-producing ability has drawn attention to its metabolic pathways, which could potentially be transferred to other organisms of interest. Here we report that the iron-containing AdhA is important for ethanol production in the high-ethanol strain of T. saccharolyticum (LL1049). A single-gene deletion of adhA in LL1049 reduced ethanol production by ∼50%, whereas multiple gene deletions of all annotated alcohol dehydrogenases except adhA and adhE did not affect ethanol production. Deletion of adhA in wild-type T. saccharolyticum reduced NADPH-linked ADH activity (acetaldehyde-reducing) by …

Performance Assessment Of Diffuse Optical Spectroscopic Imaging Instruments In A 2-Year Multicenter Breast Cancer Trial, Anais Leproux, Thomas D.O. Sullivan, Albert E. Cerussi, Amanda Durkin, Brian Hill, Nola M. Hylton, Arjun G. Yodh, Stefan A. Carp, David A. Boas, Shudong Jiang, Keith D. Paulsen, Brian W. Pogue, Darren M. Roblyr, Wei T. Yang, Bruce J. Tromberg

Dartmouth Scholarship

We present a framework for characterizing the performance of an experimental imaging technology, diffuse optical spectroscopic imaging (DOSI), in a 2-year multicenter American College of Radiology Imaging Network (ACRIN) breast cancer study (ACRIN-6691). DOSI instruments combine broadband frequency-domain photon migration with time-independent near-infrared (650 to 1000 nm) spectroscopy to measure tissue absorption and reduced scattering spectra and tissue hemoglobin, water, and lipid composition. The goal of ACRIN-6691 was to test the effectiveness of optically derived imaging endpoints in predicting the final pathologic response of neoadjuvant chemotherapy (NAC). Sixty patients were enrolled over a 2-year period at participating sites and received …

Preclinical Evaluation Of Spatial Frequency Domain-Enabled Wide-Field Quantitative Imaging For Enhanced Glioma Resection, Mira Sibai, Carl Fisher, Israel Veilleux, Jonathan T. Elliot, Frederic Leblond, David W. Roberts, Brian Wilson

Dartmouth Scholarship

5-Aminolevelunic acid-induced protoporphyrin IX (PpIX) fluorescence-guided resection (FGR) enables maximum safe resection of glioma by providing real-time tumor contrast. However, the subjective visual assessment and the variable intrinsic optical attenuation of tissue limit this technique to reliably delineating only high-grade tumors that display strong fluorescence. We have previously shown, using a fiber-optic probe, that quantitative assessment using noninvasive point spectroscopic measurements of the absolute PpIX concentration in tissue further improves the accuracy of FGR, extending it to surgically curable low-grade glioma. More recently, we have shown that implementing spatial frequency domain imaging with a fluorescent-light transport model enables recovery of …