Biomedical Studies Using Ultrasonic Holography

Ultrasonic pulse-echo techniques for medical diagnosis are finding increased acceptance. The results we have obtained using liquid-surface ultrasonic holography suggests that it has advantages over the pulse-echo method for certain applications. The formation of the hologram is analogous to the optical process [Brenden, in Acoustical Holography (Plenum Press, New York, 1969), Vol. I]. A reference and an object beam of ultrasonic energy interact at a liquid-gas interface to form a ripple pattern which serves as the hologram. The images are reconstructed in real-time by reflection and diffraction of a beam of coherent light from this liquid surface. Images may be viewed or photographed directly or recorded on video tape. A motion picture prepared from edited tape recordings will be used to illustrate our results. These include studies with experimental animals such as a live fish swimming in the holographic tank, the urogenital system of the rat, and stimulated contraction and motion of the valves of the heart. The instrument also has been used for in vivo and in vitro studies in the human: contraction of the uterus and uterofetal relationships in surgical specimens, and muscle and tendon motion in the hand.