Measurements, phantoms, and standardization

The last 25 years has seen a number of significant developments in the establishment of a measurement infrastructure supporting medical applications of ultrasound. This has allowed manufacturers and users of medical ultrasonic equipment to undertake and compare measurements of key parameters describing the magnitude or strength of the applied ultrasonic field in a meaningful and traceable way: for equipment development, standards compliance, and quality assurance purposes. This paper describes the current state of the art for measurement techniques used to determine the key properties of an ultrasonic field, principally acoustic pressure and acoustic power. Measurement tools and methodologies are described in detail, alongside considerations of how these are likely to develop, shaped by user need. The way that these measurement methods underpin a range of international and national specification standards enabling equipment manufacturers to demonstrate that their equipment is safe and fit for purpose is covered.