Date of Award

Summer 8-18-2023

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Biological Engineering

Advisor

Michael Mason

Second Committee Member

Todd O'Brien

Third Committee Member

Bruce Segee

Abstract

Osteoporosis is a medical condition in which there is a progressive degradation of bone tissue that correlates with a characteristic decrease in bone density (BD). It is estimated that osteoporosis affects over 200 million people globally and is responsible for 8.9 million fractures annually. Populations at risk for developing osteoporosis include post-menopausal women, diabetic patients, and the elderly, representing a large population within the state of Maine. Current densitometric and sonometric devices used to monitor BD include quantitative computed tomography (QCT), dual-energy x-ray absorption (DXA), and ultrasound (QUS). All methods are expensive and, in the cases of QCT and DXA, patients are exposed to small, frequent doses of ionizing radiation. While these methods can effectively measure BD, they are critically limited for applications in rural healthcare because they are cost-prohibitive to rural medical facilities and to patients that require routine screening. The diversity of at-risk patient populations, current expensive and invasive BD devices drives the need for a rapid, low-cost, and non-invasive approach to monitoring BD. The present work explores audible sound as a potential solution that could safely and effectively measure BD by minimizing cost drivers and increasing device simplicity to improve availability. The current prototype aims to measure calcaneal (heel) BD using audible sound and time delay spectroscopy (TDS).

To assess the feasibility of such a device, iterative prototypes were constructed and evaluated, a relative sensitivity analysis was performed, and testing of critical device components was completed. The testing included the ability of the device to measure the frequency and phase of a signal, measure the coupling force applied at the patient and device interface, and measure the geometries of a test material. The relative sensitivity analysis supported the use of audible sound in this application. The testing showed the device can measure the frequency and phase of a signal and the geometries of a test material while design changes are required to measure the coupling force. With the indicated improvements, the device is ready for testing materials that share similar material properties with bone.

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