High Resolution Acoustic Mapping of Gelatin-Based Soft Tissue Phantoms

Abstract

AbstractBackgroundUtilizing spatially and temporally uniform tissue-mimicking phantoms for ultrasonic applications can facilitate the characterization of beam distortion and attenuation. The implementation of acoustic phantoms can enhance the efficacy of ultrasound therapy or imaging by providing guidance on optimal ultrasonic parameters, such as frequency and power. The efficacy of phantoms is heavily dependent on the accuracy and reliability of measurement techniques employed for assessing their acoustic properties.PurposeThe work aims to develop, build, and characterize, via high resolution acoustic mapping, Gelatin-Based ultrasound (US) soft tissue phantoms. To that effect, we built acoustic maps of the intensity distribution of US waves passing through the phantoms and studied the effect of gelatin concentrations and US frequency, duty cycle, and applied voltage on the acoustic intensity and focal region of the US waves. The methodology developed here offers well characterized and reproducible Gelatin-Based US phantoms for soft tissue (both acoustically and mechanically).MethodsWe developed gelatin-based phantoms, with conveniently adjustable parameters and measured, with high resolution, the acoustic attenuation of ultrasound waves when encountering the gelatin phantoms. This was done via a motorized acoustic system built for 3D-acoustic mapping of ultrasound waves. Mechanical assessment of the phantoms’ elasticity was carried out through unconfined compression tests. We characterized tissue mimicking phantoms with realistic acoustic properties and mechanical elasticity, emphasizing the effect of varying gelatin concentration on the ultrasound maximal intensity, thus causing acoustic attenuation throughout the acoustic profile. For validation, we used computational simulations to compare our data to predicted acoustical outcomes.ResultsOur results show high-resolution mapping of US waves in fluid with and without Gelatin-Based phantoms. We also confirm the impact of recipe and gelatin concentration on mechanical and acoustic characterization of phantoms. The density of the gelatin-based phantoms scales with the Young’s modulus. When characterizing the acoustic profiles of the different ultrasound transducers, the focal areas increased systematically as a function of increasing applied voltage and duty cycle yet decreased as a function of increased ultrasonic frequency.ConclusionsWe developed a Gelatin-Based US phantoms are a reliable and reproduce tool for examining the acoustic attenuations taking place as a function of increased tissue elasticity and stiffness. High resolution acoustic maps of the intensity distribution of US can provide essential information on the spatial changes in US wave intensity and focal point enabling a more in-depth examination of the effect of tissue on US waves.