title: The effect of speed of sound in ultrasound test objects on lateral resolution.
abstract: Urethane test objects are available that are more durable than traditional gel-based objects. Their ultrasound (US) propagation speed differs from scanner calibration velocity. This is clearly a disadvantage in checking caliper accuracy, but its effect on other measurements such as resolution is not well known. A test object containing a column of nylon filaments was constructed and filled with water at different temperatures to give US speeds of 1,540 m s(-1) and 1,450 m s(-1). Images of the filaments were digitally captured and analysed to obtain the full-width half-maximum of the target images at each depth. Target image width was greater at 1,450 m s(-1). Measurements were also performed for the two types of tissue-mimicking test objects; results were in close agreement with the water test object. US beam profiles are broader in media with low propagation velocities.
authors.affiliation: Medical Physics Department, Nottingham City Hospital, Nottingham, UK. ndudley@ncht.trent.nhs.uk
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Dudley
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Gibson
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Fleckney
authors.forename: Peter D
authors.initials: PD
authors.lastname: Clark
mesh_terms: D000162:Acoustics; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D019047:Phantoms, Imaging; D011786:Quality Control; D014463:Ultrasonography / Q000295:instrumentation* / Q000592:standards; D014520:Urethane
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D014520:Urethane