Medical ultrasound and its biological effects.

The increased use of clinical ultrasound in diagnostic scanning of the pregnant uterus, in fetal monitoring, and in neonatal physiologic monitoring, have led to a concern for the safety aspects of clinically used ultrasonic dosage levels. In this paper, the current status of the understanding of the interaction mechanisms of ultrasound with biological media and the factors that govern different biological effects are surveyed. There is a critical need for further investigations to establish safe dosage levels for the fetus, and guidelines for adequate ultrasonic equipment manufacturing and management practices.