Biomedical Studies using Ultrasonic Holography

Abstract

The use of ultrasound to obtain information about the internal structure of the body has become an accepted clinical tool and a number of instruments are commercially available. Essentially all of these instruments and the associated techniques are based on the transmission of short pulses of ultrasound into the subject and measurement of the time lag and magnitude of the reflections or echos from interfaces within the body. There are a number of shortcomings associated with these so-called pulse-echo or echo-ranging techniques. These include high attenuation of the ultrasound, artifacts introduced by motion of the subject or inhomogeneities of the intervening tissues, and lack of gray scale in the image.