In biological tissue, an increase in elasticity is often a marker of abnormalities. Techniques such as quasi-static ultrasound elastography have been developed to assess the strain distribution in soft tissues in two dimensions using a quasi-static compression. However, as abnormalities can exhibit very heterogeneous shapes, a three dimensional approach would be necessary to accurately measure ...

SOUND WAVES with frequencies greater than 20,000 cycles per second are above the limits of sound audible to the human ear and, therefore, are designated as ultrasound. Over the past several years ultrasonic irradiation has been widely employed as a form of treatment in physical medicine.' Concurrently, other uses of ultrasound have been developed that utilize the particular transmission charact...

The primary technical objective is to remotely generate and detect mid-frequency elastic waves within the body of a living cetacean and to use the measured propagation parameters of these waves to obtain the complex elastic moduli by inversion. A further technical objective is to extract moduli in this manner for intracranial tissues. This objective carries considerably more technical risk sinc...

Electromagnetic compatibility (EMC) is a key issue in the design and development of safe and effective medical instruments. The treatment probes of high intensity focused ultrasound (HIFU) systems not only receive and transmit electromagnetic waves, but also radiate ultrasound waves, resulting in electromagnetic coupling. In this paper, an electromagnetic shielding method involving the enclosur...

The authors have recently demonstrated the shear wave interference patterns created by two coherent vibration sources imaged with the vibration sonoelastography technique. If the two sources vibrate at slightly different frequencies omega and omega+deltaomega, respectively, the interference patterns move at an apparent velocity of (deltaomega/2omega)upsilon(shear), where upsilon(shear) is the s...

Ultrasound is a form of mechanical energy with its acoustic pressure wave at frequencies range from 20 to 20,000 Hz. To date, ultrasound waves are not only used in imaging medicine for diagnosis, but also are performed in physical therapy (PT) medicine for the purpose of preventing and curing disease due to its thermal and nonthermal effects, and the ultrasound frequencies used in PT are typica...

Laser ultrasonics is based on the generation of elastic waves by transient surface heating or ablation with short laser pulses. These waves are traveling through the sample, are reflected and scattered at interfaces and the backside of the sample. To realize an ultrasound measurement device we have used either an interferometer coupled to a continuous wave laser (contact-free) or the sample was...

The term ultrasound refers to sound with a frequency above that which can be detected by the human ear. The audible frequency range lies between 20Hz and 20kHz (one hertz equals one cycle per second, one kilohertz equals one thousand cycles per second), whereas the frequencies of sound waves used for diagnostic applications in medicine are of the order of one thousand times higher than this, wi...

Ultrasound technology was used to analyse the freezing behaviour of orange juice. The ultrasonic properties of orange juice, specifically velocity and attenuation coefficient, were characterised as the temperature was decreased from 20 to −50 ◦C. The results were compared with NMR free induction decay data and correlated with the amount of unfrozen water present in the frozen sample. The veloci...

Interoduction: Ultrasound images have often low contrast due to small differences in acoustic impedance between different tissues. Air or gas microbubbles that surrounded by membrane are most of the contrast agents in ultrasound imaging. Problems such as instability in sound pressure and inability in penetrating from the blood vessel into body tissues limited the use of microbubbles into the in...