J. Kushibiki et al., VHF UHF RANGE BIOULTRASONIC SPECTROSCOPY SYSTEM AND METHOD, IEEE transactions on ultrasonics, ferroelectrics, and frequency control, 42(6), 1995, pp. 1028-1039
A new system and method for characterizing biological tissues in vitro
and liquids in the VHF and UHF ranges is described. Bulk acoustic pro
perties such as the sound velocity, attenuation, acoustic impedance, a
nd density are determined in reflection and transmission modes, with t
he biological tissue/liquid specimen sandwiched between the parallel s
urfaces of synthetic silica glass buffer rods having ZnO piezoelectric
film transducers on their opposite ends, The method is an ultrasonic
transmission line comparison method wherein the reference medium is di
stilled water, for which all acoustic properties are known, Measuremen
t errors due to diffraction losses in the acoustic media and to mode c
onversion at the buffer/sample interfaces are corrected, Special techn
iques for achieving precise parallelism between the two rod surfaces,
for movement to adjust the gap distance, and for signal processing are
employed in order to obtain high measurement accuracy, Attenuation an
d reflection coefficients are determined using the gated pulse echo me
thod, The sound velocity is determined with the gated pulse interferen
ce method by sweeping the ultrasonic frequency, or by changing the gap
distance, Results of measurements on castor oil, cottonseed oil, sili
cone oil, and bovine liver, in the frequency range from 10 to 500 MHz,
are presented and compared with results of earlier reports.