Biomedical Devices and Instrumentation Commons^™

Quantitative Fluorescence Imaging Using A Paired Agent Approach For Improving Surgical Decision Making, Sanjana Pannem

Dartmouth College Ph.D Dissertations

Surgical resection remains to be the cornerstone of treatment for most solid tumors, where the primary objective is to remove all visible and microscopic disease. However, the extent of tumor resection is inherently limited by the surgeon’s ability to distinguish tumor from normal tissue, intraoperatively. As a result, positive surgical margins (PSM), where residual tumor remains after surgery, are a common occurrence and are associated with increased recurrence, need for adjuvant therapies, dismal patient outcomes, and high healthcare costs.

Fluorescence guided surgery (FGS) has emerged as a promising technique to enhance intraoperative visualization of tumors and may help reduce the …

Methods For Radiation-Sparing Navigation In Endovascular And Spine Surgery, William Ross Warner

Dartmouth College Ph.D Dissertations

Modern surgical navigation systems improve procedural accuracy, limit complications, and can reduce reliance on intraoperative ionizing radiation, yet their adoption remains uneven across surgical domains. Informed by clinical immersion, this thesis identifies and addresses two unmet needs revealed through contrasting image-guidance practices in endovascular and spine surgery, where existing guidance techniques are costly, intermittent, or fundamentally limited. Specifically, these needs include (1) the absence of radiation-sparing navigation techniques for endovascular procedures, which rely heavily on 2D x-ray angiography, and (2) the need for dynamic registration methods in open spine surgery, where navigation accuracy can degrade after initial registration and intraoperative …

Volumetric Wear Analysis Of Polyethylene Orthopedic Liners Using Point Clouds, Gabriel Landi

Dartmouth College Master’s Theses

In vivo wear of ultra-high molecular weight polyethylene (UHMWPE) orthopedic bearings represents a major problem in shoulder and knee arthroplasty, with significant amounts of devices failing due to the complication itself, and even more due to associated reasons for retrieval, including aseptic loosening. However, quantification of UHMWPE wear has largely been limited to linear and in vitro volumetric analyses, obscuring the understanding of the amount of clinically relevant material loss. This study proposes new methods to measure articular, rim, and backside surfaces of retrieved shoulder and knee UHMWPE liners, centered around the coordinate measuring machine (CMM)-based collection of high density …

Design And Validation Of A Novel Patterned Microfluidic Culture Platform For Hipsc-Cm Maturation, Anisia Gabriela Țiplea

Dartmouth College Master’s Theses

Adult cardiomyocytes (CMs) are among the most challenging cells to culture in vitro, given their poor adherence to plastic culture wells and poor maturation outside the native extracellular matrix (Narkar et al., 2022). Human induced pluripotent stem cell-derived CMs (hiPSC-CMs) offer a viable alternative to study heart development and disease progression. While not comparable to adult CMs in their maturity (Narkar et al., 2022), they mimic the clinical phenotypes of heart failure and are more feasible to culture. Nevertheless, hiPSC-CMs require specialized culture conditions that cannot be achieved with 2D static culturing, which fail to replicate native tissue environments (X. …

The Implementation And Miniaturization Of A New Current Source Into The Consolidated Layout Of An Electrical Impedance Tomography Probe With A Novel Approach To Electrode Layout, Katherine M. Bullion

Dartmouth College Master’s Theses

Prostate cancer is the most highly diagnosed form of cancer in male subjects in the United States. As a result, over 100,000 radical prostatectomies are performed annually in the US [1]. However, it is currently very difficult for surgeons to confirm that all impacted tissues have been effectively removed from the patient. Positive surgical margins are an independent risk factor for the recurrence of cancer, yet currently there is no method to efficiently, intraoperatively assess the status of surgical margins during a radical prostatectomy. There is a need for a new tool that is small enough to fit into a …

Smart Toys For Sensing And Soothing Distress In Pediatric Patients, Jonathan Daniel Bonilla

Dartmouth College Master’s Theses

This thesis develops and evaluates child-centered technologies to support remote monitoring of pediatric patients, with an emphasis on childhood cancer and pediatric chronic pain. For these and many other health conditions, current therapies tend to focus on treating physical symptoms yet neglect the psycho-emotional aspects of managing the illness. However, such mental states play a major role in recovery. Research has shown that cancer patients with better mental health have better prognoses, higher possibilities of remission, and faster healing processes, while chronic pain patients with better mental health report lower levels of pain. To enable more personalized, continuous, and scalable …

Patterned Magnetic And Plasmonic Nanostructures In Microfluidics For Extracellular Vesicle Screening And Drug Loading, John H. Molinski

Dartmouth College Ph.D Dissertations

Extracellular vesicles (EVs), once dismissed as shuttles for cellular waste, have emerged as vital nanoscale biomolecules, facilitating intercellular communication through transfer of host-cell specific molecular cargo. Tumor-derived EVs, released by cancer cells, hold potential as diagnostic biomolecules due to their links to cancer cells, abundance within biofluids, and potential for direct extraction and detection. More broadly, EVs from a wide array of cellular origins have been explored as therapeutic carriers, stemming from their innate function as cargo carriers, high biocompatibility, and their ability to evade immune detection. However, harnessing EVs for diagnostic or therapeutic applications necessitates efficient isolation, purification, and …

Towards A Wearable Device For Measuring Impedance Plethysmography Of The Radial Artery, Pritom Chowdhury

Dartmouth College Master’s Theses

Recent advancements in bioimpedance technology have demonstrated significant promise in the application of cardiac health monitoring. This research explores the design and development of a forearm-based wearable bioimpedance device for non-invasive measurement of heart rate and respiratory rate at an accuracy level comparable to medical-grade monitors. It utilizes a tetrapolar electrode configuration to analyze bioimpedance changes in the radial artery due to blood flow.

An ongoing aspect of this work involves the preliminary development of an embedded framework intended to integrate signal generation, acquisition, and processing within the device to achieve compact and efficient system design, anticipated to contribute to …

Toward Electrical Impedance Sensing Surgical Drill For Tissue Boundary Detection, Harshavardhan Devaraj

Dartmouth College Ph.D Dissertations

Dental implantation is an increasingly common procedure used to treat missing teeth. However, surgical drilling to place the implant poses a high risk of injury to critical anatomy, such as inferior alveolar nerve injury or maxillary sinus perforation. A real-time surgical feedback system sensing proximity of these critical anatomy could reduce injury risks. This dissertation investigates the development of such a system that incorporates an electrical impedance sensor into the tip of a surgical drill.

A simulation framework based on finite element method (FEM) was developed to optimize the sensor as it approached a high impedance boundary. The accuracy of …

Surgical Navigation In Image-Guided Transoral Robotic Surgery, Yuan Shi

Dartmouth College Ph.D Dissertations

Transoral robotic surgery (TORS) is a minimally invasive approach in treating head and neck cancers and has demonstrated improved surgical outcomes with reduced morbidity when compared to traditional open surgery. However, the lack of haptic feedback makes it more difficult to assess the tumor extent and locate critical structures (e.g., artery and nerves). In standard-of-care TORS, preoperative imaging is used as guidance; however, it becomes inaccurate intraoperatively: the patient’s neck is hyper-extended, surgical instruments are introduced, and soft tissues deform significantly. As a result, the surgeon is required to mentally predict intraoperative deformation, which can lead to bleeding complications and …

An Fpga-Based Eit System For Deep Space Medical Imaging, Kendall R. Farnham

Dartmouth College Ph.D Dissertations

Dangers associated with high radiation and microgravity exposure in space are critical challenges inhibiting us from exploring deep space and pursuing long-duration missions, as current medical systems are unable to monitor, diagnose, or treat tissue injury within physical spacecraft constraints and communication limits. Ultrasound (US) is the current imaging system used on the International Space Station, but this technology relies on telemedical support (or onboard artificial intelligence/autonomous capabilities) for both operation and diagnosis, posing challenges for crews isolated in deep space. Electrical impedance tomography (EIT) is a non-invasive, non-ionizing technology that produces images of the electrical properties of tissues and …

Design Of Asic Based Electrical Impedance Tomography Microendoscopic System For Prostate Cancer Surgical Marginal Assessment, Mohsen Shahghasemi

Dartmouth College Ph.D Dissertations

Prostate cancer is the second most common cancer in the United States. It is typically treated by surgically excising the cancerous section of the prostate. Because there is not always a visible distinction between the healthy and cancerous sections, surgery often leaves some cancerous tissue behind. This is referred to as a positive surgical margin and it requires adjuvant treatment with adverse side effects. Electrical impedance tomography (EIT) is a low-cost low-form-factor method that can be used to assess surgical marginal intraoperatively to ensure that no cancerous tissue is left behind. EIT-based surgical margin assessment works on the principle that …

Piezoelectric And Conductive Polymer Based Flexible Devices Enabling Cardiovascular Health Sensing And Energy Harvesting, Andrew Closson

Dartmouth College Ph.D Dissertations

Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible …

Deutj: An Imagej Plugin For Improved Automatic Masking And Segmentation Of Images From Confocal Microscopy, Sunny Cui

Independent Student Projects and Publications

Due to advances in microscopic imaging, there are a plethora of biological molecules that can now be tagged and subsequentially imaged from almost any cell, organism, or tissue. However, the ability of software to analyze these images remains to be a challenge. ImageJ is open source software that allows for the processing of these images, but faces challenges when dealing with images that show weak contrast between objects of interest and background. DeutJ is an ImageJ plugin that color corrects and brightness corrects gradients that inhibit segmentation in confocal microscopy images. It can analyze hundreds of images from a given …

Zinc Oxide Based Nanomaterials And Device Designs - For Bioenergy Harvesting, Sensing And Water Purification, Congran Jin

Dartmouth College Ph.D Dissertations

Biomechanical energy harvested from the human body can power implantable electronics such as cardiac pacemakers, replacing conventional batteries and offering a lifelong energy solution. The electrical signals converted from biomechanical motions contain vital physiological information, making them suitable as a sensor to monitor one's health condition. Zinc Oxide (ZnO) is a versatile material with various intriguing properties, including piezoelectricity, photo-catalytic and piezo-catalytic properties. This thesis aims to exploit and enhance these properties of ZnO by rationally designing its nano- and micron-structures and employing them, along with other functional materials, in the development of novel biomechanical energy harvesting, water purification, and …

Mechanical Design Of A Microwave Imaging Device For Breast Cancer Detection In Mri Scanners, Grace M. Player

Dartmouth College Master’s Theses

This project seeks to develop an updated version of a microwave imaging device for use in conjunction with breast MRI, improving upon existing technology and developing novel concepts for the device. It posits three primary redesign targets for updating the previous system: resizing the system height, making the device more iteration- friendly, and improving the overall manufacturability of the device by replacing custom components with commercially available alternatives. All three of these redesign targets are met in the new design, V2.0. The height is reduced by reducing antenna travel and height, embedding some components, and shortening the tank wall, resulting …

Advanced Tools For Time-Resolved Imaging Of Tissue Metabolism, Arthur Petusseau

Dartmouth College Ph.D Dissertations

Medical imaging is a crucial tool in diagnosing and treating diseases, and by far the most common set of tools used for point-of-care guidance between a physician and patient are optical devices. For example, visible light imaging has unique applications in endoscopy, dermatology, microscopy, and this range of devices utilize a wide range of optical signals for sensing the tissue. Fluorescence imaging has become a niche but growing methodology in medical diagnostics and treatment because of its simplicity and the ability to integrate reporter molecules, that can reveal detailed information about cellular structures, metabolism, signaling, and other biomolecular features of …

Flash Radiotherapy: Skin Pigmentation As A Non-Invasive Indicator For Radiation-Induced Damage, Brady Mccallister

ENGS 88 Honors Thesis (AB Students)

FLASH ultra-high dose rate radiotherapy (RT) is one of the most rapidly growing subfields of radiation oncology today due to its potential to increase the limits of the therapeutic ratio. The FLASH effect, which includes heightened normal tissue sparing paired with iso-effective tumor cell killing, has been literature documented, in a limited manner, in rodent models, a few large animals, and one clinical patients.

A porcine-based experiment was conducted to test the effects of FLASH RT on normal tissue compared to conventional (CONV) RT. A clinical linear accelerator (LINAC) was reversibly converted to be capable of FLASH RT. A female …

Classifying Common Knee Rehabilitation Exercise Mistakes Using Imu Data, Fedor Myagkov

Dartmouth College Undergraduate Theses

Physical therapy following major surgeries is a branch of medicine that has seen its fair share of technologically inspired advances. One important facet of physical therapy, the “at-home exercises” patients are prescribed to do, is still somewhat of a “black box” to many physical therapists (PTs). PTs have no way of knowing (1) whether the patient is doing the home exercises, or (2) whether the patient is doing the exercises in the correct and healthy manner. This lack of awareness makes it difficult for the PT to guide the patient, which can often lead to prolonged rehabilitation periods or (sometimes) …

Utilizing Neural Networks And Wearables To Quantify Hip Joint Angles And Moments During Walking And Stair Ascent, Megan V. Mccabe

ENGS 88 Honors Thesis (AB Students)

Wearable sensors were leveraged to develop two methods for computing hip joint angles and moments during walking and stair ascent that are more portable than the gold standard. The Insole-Standard (I-S) approach replaced force plates with force-measuring insoles and achieved results that match the curvature of results from similar studies. Peaks in I-S kinetic results are high due to error induced by applying the ground reaction force to the talus. The Wearable-ANN (W-A) approach combines wearables with artificial neural networks to compute the same results. Compared against the I-S, the W-A approach performs well (average rRMSE = 18%, R^{2 …}

A Physical And Computational Reverse-Engineering Approach To Determine Dimensional Change And Its Relationship To Oxidation In Retrieved Orthopedic Implants, Josephine Kalshoven

ENGS 88 Honors Thesis (AB Students)

Oxidation of the Ultra-High Molecular Weight Polyethylene (UHMWPE) tibial inserts of total knee arthroplasty devices is a major factor underlying multiple modes of failure for these devices, including delamination, wear, and fracture. Previous research has demonstrated that oxidation of UHMWPE is driven by a high concentration of free radicals in the polyethylene. However, even new devices created with undetectable amounts of free radicals are oxidizing in vivo. One theory is that, in the absence of residual free radicals, oxidation is facilitated by absorbed species (e.g. lipids, ROS) delivered or exacerbated by contact stress. However, no method exists to comprehensively …

Humeral Guide For Intraosseous Vascular Access, Alexa Lewis, Colin Minor, Josephine Kalshoven, Ellie Ng, Gabriela Lowry, Alana Tucker

ENGS 89/90 Reports

Intraosseous (IO) infusion is a procedure performed in emergency situations, in order to rapidly infuse fluid or medications into a patient’s vascular system via bone marrow in the humerus or tibia. Unfortunately, the current method for identifying the humeral insertion site (palpation) can be impossible in heavily muscled or obese patients, which may result in needle misplacement, the leading cause of complications. To overcome these difficulties, this project, sponsored by IOMETRY, Inc., focused on the development of an insertion site guide, which is compatible with current IO access equipment and allows rapid and accurate identification of the humeral insertion site.

Rethinking Solutions For Male Incontinence, Martin S. Gross, Jayanth V. Batchu, Douglas R. Beahm, Rebecca J. Conway, Aamuktha Porika, Noura Srour

ENGS 89/90 Reports

Following a radical prostatectomy, the main surgical treatment for prostate cancer, a majority of men will experience some level of urinary incontinence. When severe, this incontinence creates social isolation, leads to risk of infection from dried urine, and prevents men from participating in activities they love. The most common treatment in the US is a surgically placed AMS 800, produced by Boston Scientific. The AMS 800 surgery is highly invasive with a lengthy recovery time. Also, the device requires manual activation using a pump in the scrotum and erodes the urethra over time by constant compression.

Our group’s design is …

Singular Value Decomposition Metrics Show Limitations Of Detector Design In Diffuse Fluorescence Tomography, Frederic Leblond, Kenneth M. Tichauer, Brian W. Pogue

Dartmouth Scholarship

The spatial resolution and recovered contrast of images reconstructed from diffuse fluorescence tomography data are limited by the high scattering properties of light propagation in biological tissue. As a result, the image reconstruction process can be exceedingly vulnerable to inaccurate prior knowledge of tissue optical properties and stochastic noise. In light of these limitations, the optimal source-detector geometry for a fluorescence tomography system is non-trivial, requiring analytical methods to guide design. Analysis of the singular value decomposition of the matrix to be inverted for image reconstruction is one potential approach, providing key quantitative metrics, such as singular image mode spatial …