The dosimetry of small ultrasonic beams

Wells, P.N.T.; Bullen, M. A.; Follett, D H; Freundlich, H.; James, John A.

doi:10.1016/0041-624x(63)90062-3

Cited by 40 publications

(14 citation statements)

References 5 publications

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“…The use of multiple thermal sensors can cater better for nonuniform heating distributions provided that the number of sensors is adequate and that their presence does not affect the absorption process. It has been proposed previously for the measurement of ultrasound power or intensity (Wells 1963;Mikhailov 1964;Lloyd 1967;van den Ende 1969;Herman and Stewart, 1973;Zapf et al 1976;Torr and Watmough 1977;Delchar and Melvin, 1994). To do this in a HIFU field where the Ϫ6 dB focal diameter may be 1 mm or less would require an extremely high sensor density.…”

Section: Principlesmentioning

confidence: 98%

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

Shaw

2008

Ultrasound in Medicine & Biology

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Section: Principlesmentioning

confidence: 98%

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

Shaw

2008

Ultrasound in Medicine & Biology

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“…All of the improvements dealt with absolute procedures to quantify second-order quantities, and consisted of ultrasonic intensity via thermocouple probe (Fry and Fry, 1954a,b;Fry and Dunn, 1957;Dunn and Breyer, 1962) and electrodynamic method (Filipczynski, 1967), and ultrasonic power via radiation pressure and calorimetry (Wells et al, 1963) and radiation pressure balance (Newell, 1963;Kossoff, 1965).…”

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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“…This approach was used in early work on calibration of power transducers used for treating Menie`re's disease (Wells et al 1978). Whilst this particular application does not call for very high sensitivity, calorimetric methods can be developed to be highly sensitive, and a good indication of what is possible is the parallel work that has been carried out with ionising radiation dosimetry (Laughlin & Genna 1966).…”

Section: Calorimetrymentioning

confidence: 98%

Detection and Measurement of Acoustic Fields

Hill

2004

Physical Principles of Medical Ultrasonics

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The dosimetry of small ultrasonic beams

Cited by 40 publications

References 5 publications

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

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

Ultrasound–biophysics mechanisms

Detection and Measurement of Acoustic Fields

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