Validated ultrasonic power measurements up to 20 w

A Buoyancy Method for the Measurement of Total Ultrasound Power Generated by HIFU Transducers

“…The total ultrasound output power of a HIFU system is a key quantity related to the delivered dose during clinical treatment. Traditionally, the use of a radiation force balance has been considered the most accurate method of measuring ultrasound power: it is described in detail in the literature (for example Greenspan et al 1978;Benjavic and Carson 1980;Stewart 1982;Tsciegg et al 1983;Livett 1984;Davidson 1991;Beissner et al 1996;Beissner 1999aBeissner , 1999bBeissner , and 2002Hekkenberg et al 2000;2001, Hekkenberg et al 2006Sutton et al 2003) and in IEC standard 61161 (IEC61161 (2006)). …”

Calibration and measurement issues for therapeutic ultrasound

“…Recent collaborative research carried out with European Community (EC) support has developed primary standard force balances using absorbing and reflecting targets in the therapy power ranges [37], with uncertainties of ±7%. An adaptation of the radiation force balance approach has been produced, in which the measurement container and absorbing target are a single entity -the so-called absorbing well [39].…”

“…The proportional power/radiation force relationship assumes plane wave propagation. In practice, corrections are applied to the measured power to account for deviations from plane wave behaviour, and for the attenuation of ultrasound in the water path [36,37]. Acoustic streaming [38] is a well-known phenomenon that occurs during ultrasound propagation, due to attenuation in the medium, which can affect measurements of radiation force, but its influence at low MHz frequencies used in physiotherapy ultrasound is small, and so it will not be considered here.…”

Transfer standard device to improve the traceable calibration of physiotherapy ultrasound machines

“…A correction method for the nonplane field structure (Beissner 1987) has been refined (Hekkenberg et al 2000;Hekkenberg et al 2001) and is embodied in the correction, corr C 1 . A second correction (corr C 2 ) is applied because measurement of power takes place at a finite distance from the transducer and has to be corrected to give the power generated at the emitting surface of the transducer (Hekkenberg et al 2000;Hekkenberg et al 2001). This correction automatically accounts for attenuation in the water path.…”