Optimization of sound-absorbent material employment in phantoms for echographic imaging studies

The knowledge of ultrasound contrast agent (UCA) behaviour is continuously improving, mainly thanks to "in vitro" measurements performed by means of specific phantoms, mimicking the acoustic properties of several human body districts. For such purposes, it is necessary to develop experimental setups able to minimise chemical and physical effects due to environmental conditions. In this paper we discuss the design of a new tissue-mimicking phantom, specifically evaluating the sound-absorption properties of three synthetic materials (Polyurethane, Airex©, ethylene vinyl acetate (EVA©)) laid on the bottom of the phantom. Our goal is to establish the best material to use in order to minimise the artefacts within the tissue-mimicking matrix. Polyurethane showed the best sound-absorbent behaviour for every tested ultrasound frequency, so its employment in covering the bottom of tissue-mimicking phantoms is suggested in order to allow experimental investigations of acoustic properties of different UCAs without additional aspects due to environmental boundary conditions.