Tj. Esward et Jr. Blakey, ULTRASONIC CHARACTERIZATION OF INHOMOGENEOUS MATERIALS - SOME PROBLEMS WITH MEASUREMENTS OF FORWARD SCATTERED FIELDS, Ultrasonics, 34(2-5), 1996, pp. 499-502
Citations number
8
Categorie Soggetti
Acoustics,"Radiology,Nuclear Medicine & Medical Imaging
Measurements of the complex pressure fields transmitted by scattering
specimens consisting of glass beads in silicone rubber and of in vitro
samples of ox myocardium, liver and kidneys have been carried out by
point-by-point mapping of the amplitude and phase of the fields, using
a new design of PVDF needle hydrophone in a high precision scanning t
ank. The results show that disruption of the phase fronts by the speci
mens is small and the measured values depend on the choice of measurem
ent distance and frequency, and spatial sampling interval. As a result
, there is little difference between phase sensitive and phase insensi
tive measurements at frequencies below 5 MHz. It is therefore unlikely
that the proposed method could be applied successfully to the charact
erisation of such materials at low megahertz frequencies.