title: Speed of sound in rubber-based materials for ultrasonic phantoms.
abstract: OBJECTIVE
  In this work we provide measurements of speed of sound (SoS) and acoustic impedance (Z) of some doped/non-doped rubber-based materials dedicated to the development of ultrasound phantoms. These data are expected to be useful for speeding-up the preparation of multi-organ phantoms which show similar echogenicity to real tissues.
  
  
  METHODS
  Different silicones (Ecoflex, Dragon-Skin Medium) and polyurethane rubbers with different liquid (glycerol, commercial detergent,N-propanol) and solid (aluminum oxide, graphene, steel, silicon powder) inclusions were prepared.SoSof materials under investigation was measured in an experimental setup andZwas obtained by multiplying the density and theSoSof each material. Finally, an anatomically realistic liver phantom has been fabricated selecting some of the tested materials.
  
  
  RESULTS
  SoSandZevaluation for different rubber materials and formulations are reported. The presence of liquid additives appears to increase theSoS, while solid inclusions generally reduce theSoS. The ultrasound images of realized custom fabricated heterogeneous liver phantom and a real liver show remarkable similarities.
  
  
  CONCLUSIONS
  The development of new materials' formulations and the knowledge of acoustic properties, such as speed of sound and acoustic impedance, could improve and speed-up the development of phantoms for simulations of ultrasound medical procedures.
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa, Italy.
authors.forename: A
authors.identifier: 0000-0002-0626-8652
authors.initials: A
authors.lastname: Cafarelli
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Miloro
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Verbeni
authors.affiliation: EndoCAS Center, Università di Pisa, Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Carbone
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant'Anna, Viale Rinaldo Piaggio 34, 56025 Pontedera, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Menciassi
mesh_terms: D000433:1-Propanol; D000537:Aluminum Oxide; D003902:Detergents; D004867:Equipment Design; D005990:Glycerol; D006108:Graphite; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008954:Models, Biological; D019047:Phantoms, Imaging; D011140:Polyurethanes; D012408:Rubber; D012825:Silicon; D012828:Silicones; D013016:Sound; D013232:Steel; D014463:Ultrasonography / Q000295:instrumentation*
chemical_list: D003902:Detergents; D011140:Polyurethanes; D012828:Silicones; D013232:Steel; D006108:Graphite; D012408:Rubber; D000433:1-Propanol; D000537:Aluminum Oxide; D005990:Glycerol; D012825:Silicon
keywords: Acoustic characterization; Acoustic impedance; Silicone phantoms; Speed of sound measurement