Holley Stewart

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Determination of in situ ultrasound exposures in experimental animals and patients is necessary to assess any potential hazard of ultrasound implied by reported biological effects in animals. A layered model was used to calculate total attenuation of ultrasound pulses as they passed through tissue layers to an organ site, thus enabling calculation of in(More)
The growth of ultrasound applications in diagnostic medicine has helped stimulate related biological effects investigations. Current data related to effects associated with diagnostic ultrasound indicate the need for additional research on cell surface structures, motility and developmental effects. Research on biological effects, especially for evaluating(More)
A compilation of reports of biological effects and related ultrasound exposure levels can be useful in the identification of trends in effects data that may be developing in the literature. The exposures in the experiments reviewed were at frequencies used in medicine. For short (10 minutes or less) continuous wave exposure, with the exception of behavioral(More)
This paper examines determinants of one aspect of sexual behaviour--coital frequency--among 2,188 married women in the Central African Republic using a secondary analysis of data from the Demographic and Health Survey of 1994-95. Female genital cutting (or circumcision) is practised in the Central African Republic and self-reported circumcision status was(More)
Ultrasonographic B-mode images were obtained at various exposure levels with three real-time diagnostic scanners. Adult human and tissue-equivalent phantom images were compared in terms of diagnostic content and depth of penetration. For the exposure level settings used, spatial-peak pulse-average intensities ranged from approximately 10 to 500 W/cm2. At(More)
A regulatory performance standard for ultrasound therapy equipment has been published by the Bureau of Radiological Health under the authority of The Radiation Control for Health and Safety Act of 1968. To clarify this standard and its intents, a number of topics relevant to the use of ultrasound in physical therapy are discussed, including the physics of(More)