An ultrasonic human-blood-flow velocity profile measurement method using time-domain correlation of consecutive echo pairs has been developed. The time shift between a pair of range gated echoes is estimated by searching for the shift that results in the maximum correlation. The time shift indicates the distance a group of scatterers has moved, from which flow velocity is estimated. The basis for the computer simulations and error analyses of the scheme includes a band-passed white Gaussian noise signal model for an echo from a scattering medium, the estimate of flow velocity from both a single scatterer and multiple scatterers, and a derived precision estimation. The error analysis via computer simulation includes an evaluation of errors associated with the correlation method. For a uniform flow velocity profile, beamwidth modulation represents the greatest error source. However, for a nonuniform flow velocity profile, the jitter caused by a small flow velocity gradient can exceed the other error sources. A detailed computer simulation evaluated the interdependencies of window length, beam width, vessel diameter, and viewing angle on the estimation of flow velocity.

Imaging technologies for in vivo functional and molecular imaging in small animals have undergone a very fast development in the last years with very intense competition to further develop resolution and molecular sensitivity. Among the imaging technologies available, ultrasound-based molecular imaging methods are of particular interest, since the use of ultrasound contrast agents allows specific and sensitive depiction of molecular targets. Together with new developments in quantification methods of targeted microbubbles, sonography represents a dynamic and seminal tool for molecular imaging.

The successful use of targeted ultrasound contrast agents (USCAs) for qualitative US-based imaging has been shown by several academic and industrial research groups in different animal models. Furthermore, techniques have been developed that enable the in-vivo quantification of targeted microbubbles (MBs). USCAs for quantitative functional and molecular imaging in small animals can be used for a more detailed characterization of new and established disease models and provide quantitative biological insights into the interaction between drug and target or target and disease in living animals. The advantages of such contrast agents in research and development are seen to be as follows: new functional or molecular findings in the complex biology of disease development, these findings can lead to new therapeutic strategies or drug candidates, a better understanding of the treatment effects of new and existing drug candidates, a more sensitive and specific characterization of early treatment effects in living animals, identification of in-vivo biomarkers for translational medicine. Further outcomes are seen in speeding up the evaluation of new drug compounds and in a reduction of the number of animals used for biomedical research.

No abstract

PZT coatings have been produced in the thickness range of S-200 microns using a composite sol gel process high frequency transducers suitable for ultrasound [l]. The application of this process in the fabrication of biomicroscopy (UBM) has been investigated. Curved single element transducers have been produced in a range of 70-165MHz with -6dB bandwidths as high as 52% and minimum insertion losses ranging from -47 to -58dB. Laser micromachining techniques for patterning linear array smctures to operate at similar frequencies have been through 20pm of ceramic have been achieved with a developed. Trenches <10pmwide with a 50% taper pulsed frequency doubled Nd:YAG laser. Trenches Spm wide with straight walls have been achieved using a pulsed KrF excimer laser.