Electronic Theses and Dissertations

Date of Award

1-1-2025

Document Type

Thesis

Degree Name

M.S. in Physics

First Advisor

Cecille Labuda

Second Advisor

Likun Zhang

Third Advisor

Joel Mobley

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

Preparing tissue-mimicking phantoms for brain ultrasound studies presents unique challenges due to the need to replicate the complex acoustic properties of cerebral tissue. Human brain tissue exhibits a speed of sound typically between 1520 and 1540 m/s, an attenuation coefficient ranging from 0.58 to 2.42 dB/cm in the 1–3 MHz frequency range, and a notably low backscatter coefficient between –94 and –82 dB/(cm・sr). Accurately reproducing these parameters simultaneously in a synthetic phantom is difficult because of the naturally low scattering properties of brain tissue and the interdependence of ultrasonic attenuation and scattering mechanisms. Polyvinyl alcohol (PVA) has emerged as a promising base material for fabricating brain phantoms due to its tunable mechanical and acoustic properties, achieved through freeze–thaw cycling and the incorporation of scattering additives such as talcum powder. These methods allow semi-independent adjustment of speed of sound, attenuation, and backscatter properties. The use of PVA-based phantoms provides a stable, non-toxic, and reproducible platform suitable for repeated experimental studies. In this study, a PVA-based phantom of the brain that was developed by Taghizdeh et al.[1] is acoustically characterized. The acoustic properties measured in this study are compared to the measurements previously published and to the acoustic properties of human brain tissue. This phantom provide a standardized tool for ultrasound research and clinical training. Such phantoms have significant potential to advance neurosonography techniques, assist in transducer calibration, and support therapeutic ultrasound development, especially in resource-limited settings where conventional imaging modalities like Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) are often inaccessible. By enabling controlled, ethical, and repeatable experiments, tissue-mimicking phantoms serve as crucial models in the advancement of ultrasound-based brain diagnostics and treatments.

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