Biomedical Engineering and Bioengineering Commons^™

Development Of A Near-Full-View Angle Coverage Photoacoustic Tomography System And Its Application Towards Optical Fluence Distribution Imaging, Lawrence Cm Yip

Electronic Thesis and Dissertation Repository

Photoacoustic tomography (PAT) is a widely explored hybrid imaging modality combining advantages of ultrasound and optical imaging. However, on the acoustic detection side, limited-view angle coverage and limited-detector bandwidth are common key issues in PAT systems that result in unwanted artifacts. While analytical and simulation studies of limited-view artifacts are extensive, experimental setups capable of comparing limited-view to an ideal full-view case are lacking. Due to the lack of PAT systems capable of artifact-free full-view imaging, applications for such a system have also been left unexplored.

A custom ring-shaped detector array was assembled and mounted to a 6-axis robot, which …

Development Of A Hybrid Stereotactic Guidance System For Percutaneous Liver Tumour Ablation, Joeana N. Cambranis Romero

Electronic Thesis and Dissertation Repository

Stereotactic Image-Guided Surgical Navigation System (IGSNS) supports percutaneous procedures by using medical imaging and tracking information, to assist the surgeons in the preprocedural planning and intraprocedural steps. This thesis describes the development of a stereotactic IGSNS for percutaneous liver tumour ablation, the goal of which is to assist in positioning the tip of the ablation applicator accurately to ensure complete tumour coverage. The main system improvement is the employment of a mini stereotactic patient-attach aiming device that is used as a pointer to ensure needle tip position prior to needle insertion. The thesis chapters describe the development and validation of …

Intracardiac Ultrasound Guided Systems For Transcatheter Cardiac Interventions, Hareem Nisar

Electronic Thesis and Dissertation Repository

Transcatheter cardiac interventions are characterized by their percutaneous nature, increased patient safety, and low hospitalization times. Transcatheter procedures involve two major stages: navigation towards the target site and the positioning of tools to deliver the therapy, during which the interventionalists face the challenge of visualizing the anatomy and the relative position of the tools such as a guidewire. Fluoroscopic and transesophageal ultrasound (TEE) imaging are the most used techniques in cardiac procedures; however, they possess the disadvantage of radiation exposure and suboptimal imaging. This work explores the potential of intracardiac ultrasound (ICE) within an image guidance system (IGS) to facilitate …

Characterization Of Fundamental Parameters That Modulate Acoustofluidic-Mediated Molecular Delivery To Cells., Connor Sterling Centner

Electronic Theses and Dissertations

Cell-based therapies represent the latest biotechnological revolution in medicine, but significant limitations exist in non-viral intracellular delivery techniques during manufacturing of cell therapies. To address these limitations, a novel acoustofluidic device was developed to deliver ultrasound waves into a flow chamber for rapid molecular delivery to human cells. Our acoustofluidic device delivers biomolecules by inducing expansion and collapse of exogenous gas-filled microbubbles (“cavitation”), which enhances molecular delivery to nearby cells. Experimental studies were conducted to characterize key parameters that influence acoustofluidic-mediated molecular delivery to human cells. A clinical ultrasound transducer was generally utilized with varying cationic microbubble concentrations. Intracellular delivery …

Multimodal Ultrasound Imaging For Improved Metastatic Lymph Node Detection, Sidhartha Jandhyala

Dartmouth College Ph.D Dissertations

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and is complex in nature due to the variety of organs located in the head and neck region. Knowing the metastatic state of the lymph nodes is paramount in accurately staging and treating HNSCC patients. Currently, metastatic lymph node detection involves the use of magnetic resonance imaging and/or x-ray computed tomography, followed by biopsies for histological confirmation. The main diagnostic criteria is the size of the nodes; however, current imaging methods are not 100% accurate due natural lymph node variability. Ultrasound imaging is able to provide …

Photonic Crystal Hydrogels: Simulation, Fabrication & Biomedical Application, Mehenur Sarwar

FIU Electronic Theses and Dissertations

Photonic crystal (PhC) hydrogels are a unique class of material that has tremendous promise as biomedical sensors. The underlying crystal structure allows for simple analysis of microstructural properties by assessing the diffraction pattern generated following laser illumination. The hydrogel medium provides elasticity, regenerability, and potential functionalization. Combining these two properties, photonic crystal hydrogels have the potential for sensing physical forces and chemical reagents using a low-cost, reusable platform.

The development of biomedical sensors using this material is limited due to the lack of a method to accurately predict the diffraction pattern generated. To overcome this, a computational model was developed …

Phase-Changing Nanodroplets As Nanotheranostic Platform For Combination Cancer Therapy, Catalina-Paula Spatarelu

Dartmouth College Ph.D Dissertations

Cancer is a cluster of diseases, and 1.8 million Americans are newly diagnosed each year. Treatment issues such as drug instability, the occurrence of severe side effects, as well as resistance make the need for solutions to improve conventional methods, like chemotherapy, apparent. Nano-sized drug-delivery platforms, particles loaded with therapeutic molecules that escape the immune system clearance and accumulate at the tumor site, were proposed as one of these solutions. Despite the expansion of the field, several aspects still need to be addressed: inconsistent delivery of the drugs, inability of measuring the effective dose being delivered to the tumor, lack …

Characterizing Locomotor Disturbance Perception In Young Adults, Daniel James Liss

Graduate Theses, Dissertations, and Problem Reports

Falls during walking are a leading cause of injuries across aging. Many of these falls are due to slips and trips. The ability to perceive disturbances to ongoing motion may play an important role in the control of walking balance. However, disturbance perception has been investigated in standing balance, but its role in walking balance due to slip- and trip-like disturbances remains largely unknown. Characterizing locomotor disturbance perception in young adults may lead to a more comprehensive understanding of sensorimotor walking balance control.

This work defined locomotor disturbance perception in response to slip and trip-like disturbances in young adults. We …

Radial Artery Model For Catheterization Procedures, Kyla Beville, Mitchell Gagnon, Benjamin Stalls, Maya Ariza

Williams Honors College, Honors Research Projects

The purpose of this project was to create a radial artery model that is usable under ultrasound that would reduce complications during catheterization procedures. Each year, over one million of these procedures are done and complications can affect the outcomes of the patient. Using ultrasound during these procedures is an upcoming way to reduce these complications and improve the outcome that a patient will have.