The impact of piezoelectric PVDF on medical ultrasound exposure measurements, standards, and regulations

This paper describes the development of PVDF hydrophones for characterizing medical ultrasound fields. The polymer hydrophone approaches that have re suited from this work are discussed, with emphasis given to the spot-poled membrane design that has become the de facto reference device for these mea surements. The various national and international standards and regulations that have followed from the successful use of PVDF hydrophones also are su mmarized. The works discussed encompass polymer-based hydrophones designed primarily for diagnostic and lithotripsy exposure measurements, both in wat er and in vivo. The advent of these hydrophones has made possible accurate and reliable measurements of exposure levels encountered in medical ultraso und and, thus, has allowed questions of ultrasound bioeffects and device sa fety to be addressed in a consistent and scientifically sound manner.