title: Acoustical characterization of polysaccharide polymers tissue-mimicking materials.
abstract: Tissue-mimicking phantoms play a crucial role in medical ultrasound research because they can simulate biological soft tissues. In last years, many types of polymeric tissues have been proposed and characterized from an acoustical and a thermal point of view, but, rarely, a deep discussion about the quality of the measurements, in terms of the uncertainty evaluation, has been reported. In this work, considering the necessity to develop laboratory standards for the measurement of ultrasonic exposure and dose quantities, a detailed description of the experimental apparatuses for the sound speed and the attenuation coefficient measurements is given, focusing the attention on the uncertainty evaluation both of the results and analysis algorithms. In particular, this algorithm reveals a novel empirical relation, fixing a limit to the energy content (therefore limits the number of cycles) of the three parts in which the authors have proposed to divide the acoustical signal. Furthermore, the realisation of multi-components phantoms, Agar and Phytagel based tissue-mimicking gels along with others long chain molecules (dextrane or polyvinyl alcohol) and scattering materials (silicon carbide and kieselguhr) are investigated. This paper reports accurate speed of sound and attenuation coefficient measurements. Speed of sound is measured by a pulse-echo technique in far-field condition, using an optical glass buffer rod; while attenuation coefficient is determined by an insertion technique, using demineralized water as reference material. The experimental sound speed results are subjected to an overall estimated relative uncertainty of about 1.5% and the attenuation coefficient uncertainty is less than 2.5%. For the development of laboratory standards, a detailed analysis of the measurement uncertainty is fundamental to make sample properties comparable. The authors believe this study could represent the right direction to make phantoms characterizations referable and traceable.
authors.affiliation: INRiM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy. Electronic address: r.cuccaro@inrim.it.
authors.forename: Rugiada
authors.initials: R
authors.lastname: Cuccaro
authors.affiliation: INRiM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy. Electronic address: c.musacchio@inrim.it.
authors.forename: Chiara
authors.initials: C
authors.lastname: Musacchio
authors.affiliation: INRiM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy. Electronic address: a.albo@inrim.it.
authors.forename: P Alberto
authors.initials: PA
authors.lastname: Giuliano Albo
authors.affiliation: INRiM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy. Electronic address: a.troia@inrim.it.
authors.forename: Adriano
authors.initials: A
authors.lastname: Troia
authors.affiliation: INRiM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy. Electronic address: s.lago@inrim.it.
authors.forename: Simona
authors.initials: S
authors.lastname: Lago
mesh_terms: D000162:Acoustics; D000465:Algorithms; D004548:Elasticity; D011108:Polymers; D011134:Polysaccharides; D014465:Ultrasonics
chemical_list: D011108:Polymers; D011134:Polysaccharides
keywords: Attenuation coefficient; Sound speed; Tissue-mimicking material; Ultrasound; Uncertainty evaluation