An Ultrasonic Absolute Power Transfer Standard

Fick, Steven E.; Breckenridge, F. R.; Tschiegg, Carroll E.; Eitzen, D. G.

doi:10.6028/jres.089.012

Cited by 20 publications

(19 citation statements)

References 4 publications

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“…Two types of PVDF hydrophones were developed, viz., needle (Lewin, 1981) and membrane (DeReggi et al, 1981;Bacon, 1982;Harris, 1982;Preston et al, 1983). The US National Bureau of Standards (now the National Institute of Standards and Technology, NIST) developed an ultrasound power transfer standard (Fick et al, 1984), and the UK National Physical Laboratory developed both a two-transducer reciprocity technique and an optical technique (Smith, 1986). …”

Section: A Brief Historymentioning

confidence: 99%

Ultrasound–biophysics mechanisms

O’Brien

2007

Progress in Biophysics and Molecular Biology

609

416

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Ultrasonic biophysics is the study of mechanisms responsible for how ultrasound and biological materials interact. Ultrasound-induced bioeffect or risk studies focus on issues related to the effects of ultrasound on biological materials. On the other hand, when biological materials affect the ultrasonic wave, this can be viewed as the basis for diagnostic ultrasound. Thus, an understanding of the interaction of ultrasound with tissue provides the scientific basis for image production and risk assessment. Relative to the bioeffect or risk studies, that is, the biophysical mechanisms by which ultrasound affects biological materials, ultrasound-induced bioeffects are generally separated into thermal and nonthermal mechanisms. Ultrasonic dosimetry is concerned with the quantitative determination of ultrasonic energy interaction with biological materials. Whenever ultrasonic energy is propagated into an attenuating material such as tissue, the amplitude of the wave decreases with distance. This attenuation is due to either absorption or scattering. Absorption is a mechanism that represents that portion of ultrasonic wave that is converted into heat, and scattering can be thought of as that portion of the wave, which changes direction. Because the medium can absorb energy to produce heat, a temperature rise may occur as long as the rate of heat production is greater than the rate of heat removal. Current interest with thermally mediated ultrasound-induced bioeffects has focused on the thermal isoeffect concept. The non-thermal mechanism that has received the most attention is acoustically generated cavitation wherein ultrasonic energy by cavitation bubbles is concentrated. Acoustic cavitation, in a broad sense, refers to ultrasonically induced bubble activity occurring in a biological material that contains pre-existing gaseous inclusions. Cavitation-related mechanisms include radiation force, microstreaming, shock waves, free radicals, microjets and strain. It is more challenging to deduce the causes of mechanical effects in tissues that do not contain gas bodies. These ultrasonic biophysics mechanisms will be discussed in the context of diagnostic ultrasound exposure risk concerns.

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Section: A Brief Historymentioning

confidence: 99%

Ultrasound–biophysics mechanisms

O’Brien

2007

Progress in Biophysics and Molecular Biology

609

416

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“…In accordance with the above guidelines, 10 independent measurements are made of the NIST power standard source [8] using a radiation force balance. The experimental procedure for setting up and using the reference source must be scrupulously followed according to the directions provided by NIST [8].…”

Section: Calibration Of Radiation Force Balancementioning

confidence: 99%

“…The experimental procedure for setting up and using the reference source must be scrupulously followed according to the directions provided by NIST [8].…”

Section: Calibration Of Radiation Force Balancementioning

confidence: 99%

Specification of acoustic output level and measurement uncertainty in ultrasonic exposimetry

Ziskin

2003

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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This manuscript was written to bring together the pertinent statistical procedures for specifying acoustic output values and measurement uncertainties of ultrasound devices, and to present them in a way that would be clear and convenient to the reader. Implementations of these procedures are illustrated in several examples: measurement of ultrasonic power of a single transducer, measurement of the power output of a transducer model, and measurement of the power output of an ultrasound scanner series. This manuscript is intended to be helpful to ultrasound device manufacturers who need to specify these quantities when applying for Food and Drug Administration (FDA) approval to market their new devices. It also is intended to be helpful to ultrasound users who need to interpret these values in order to meaningfully evaluate the relative risks and benefits of performing ultrasound examinations on their patients.

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“…They also received instructions for use of the standard source and were referred to previous publications [8][9][10][11] for a comprehensive description of the PRS. Briefly, the source is made of a lithium niobate crystal operating at the fundamental resonance frequency of approximately 1 MHz.…”

Section: National Institute Of Standards and Technology Prsmentioning

confidence: 99%

“…1,[4][5][6][7] The power was produced by the National Institute of Standards and Technology (NIST, Gaithersburg, MD; formerly National Bureau of Standards) reference power source. [8][9][10][11] The reference power source uses lithium niobate as the piezoelectric material and constitutes a convenient, transportable, and traceable standard source designed to operate in a frequency range similar to that used in clinical sonographic imaging. Therefore, it was considered an appropriate reference for interlaboratory calibration.…”

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confidence: 99%

Interlaboratory Acoustic Power Measurement

Lewin

Barrie-Smith

Ide

et al. 2003

Journal of Ultrasound in Medicine

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Objective. This article describes an American Institute of Ultrasound in Medicine-sponsored intercomparison of the results of acoustic power measurements performed by several laboratories. Methods. Two primary calibration techniques, namely, planar scanning and radiation force balance, were used in the frequency range typical of that in which sonographic imaging devices operate. The same reference source, the National Institute of Standards and Technology (Gaithersburg, MD) standard ultrasonic power source, capable of producing acoustic fields in the frequency range from approximately 1 to 21 MHz, was circulated to 3 laboratories. Results. The results of the calibrations indicate that the overall uncertainty in acoustic power measurements depends on the target and the measurement method. In the case of radiation force balance measurements with an absorbing target, the largest discrepancy between the available National Institute of Standards and Technology-calibrated results and the reported data was 10.6% at approximately 2.5 MHz. At higher frequencies, beyond 10 MHz, the largest discrepancy reported with an absorbing target was 8.4%. For a reflecting target, the largest discrepancies were 16.2% at approximately 3.7 MHz and 15.4% at about 10 MHz. The largest discrepancy identified for the planar scanning technique below 10 MHz was 7.4% at 3.7 MHz. Conclusions. The results obtained suggest that an absorbing target may be preferable for acoustic power measurements with radiation force balance. In a group that consists of 2 research laboratories and 1 manufacturer, the power measurements agreed within 16%. Key words: planar scanning technique; radiation force balance; ultrasonic hydrophones; ultrasonic transducers.

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An Ultrasonic Absolute Power Transfer Standard

Cited by 20 publications

References 4 publications

Ultrasound–biophysics mechanisms

Ultrasound–biophysics mechanisms

Specification of acoustic output level and measurement uncertainty in ultrasonic exposimetry

Interlaboratory Acoustic Power Measurement

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