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BRL Abstracts Database |
Your search for ultrasound produced 3296 results. Page 249 out of 330
Title |
The antivascular action of physiotherapy ultrasound on murine tumors. |
Author |
Wood AKW, Ansaloni S, Ziemer LS, Lee WMF, Feldman MD, Sehgal CM. |
Journal |
Ultrasound Med Biol |
Volume |
|
Year |
2005 |
Abstract |
This study was aimed at determining if physiotherapy ultrasound (US) affected the fragile and leaky angiogenic blood vessels in a tumor. In 22 C3HV/HeN mice, a subcutaneous melanoma (K173522) was insonated (1,2 or 3 min) with continuous 1-MHz low-intensity (spatial-average temporal-average = 2.28 W cm-2), physiotherapy US. Contrast-enhanced (0.1 mL Optison) power Doppler US observations were made and histogram analyses of the images were performed. Before insonation, all but 7 % of the tumor was perfused. The avascular area in tumors receiving 3-min treatment increased to 82% (p < 0.001). A linear regression analysis showed that each min of insonation led to a 25% reduction in tumor vascularity; the antivascular activity persisted for 24 h. Histology demonstrated disruption of vascular walls and tumor cell death in areas of vascular congestion and thrombosis. Physiotherapy US particularly targeted the vascular structures, and the effects on tumor cells appeared to be secondary to the resultant ischemia. |
Title |
The application of a fractal model to the scattering of ultrasound in biological media. |
Author |
Javanaud C. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1989 |
Abstract |
The implications of a fractal model of medium structure for the angular dependence of the ultrasonic differential scattering cross section and for the frequency dependence of the total ultrasonic scattering cross section are explored. The results for the differential scattering cross section agree well with published experimental values for liver and those for the total scattering cross section are not inconsistent with the literature data. |
Title |
The application of transducer arrays in ultrasound computerized tomography. |
Author |
Hiller D, Ermert H. |
Journal |
Proc Ultrason Int Conf |
Volume |
|
Year |
1979 |
Abstract |
A system for Ultrasound Computerized Tomography is investigated, which uses linear transducer arrays instead of a mechanically scanned pair of focused transducers. Such an array based system is able to work in a very fast manner. The results of some experiments, carried out on waterimmersed sponge phantoms are reported. |
Title |
The application of ultrasound in labyrinthine disturbances. |
Author |
Kossoff G. |
Journal |
Proc IREE Aust |
Volume |
|
Year |
1964 |
Abstract |
Vertigo and other labyrinthine disturbances have been successfully treated by ultrasonic irradiation. Some of the audiometric tests being used in diagnosing these conditions are described. The initial Italian generator and its performance are analysed. The acoustic and electric design of the Commonwealth Acoustic Laboratories (C.A.L.) transistorised ultrasonic generator and focused probe is outlined. The method employed in measuring the ultrasonic power output and the clinical results obtained are discussed. |
Title |
The application of ultrasound locating techniques to opthalmology. Part I. Theoretical considerations and acoustic properties of ocular media. |
Author |
Baum GB, Greenwood I. |
Journal |
Rep Natl Inst Health |
Volume |
|
Year |
unknown (late 50's) |
Abstract |
This manuscript is presented in an incomplete form to enable the review committee to evaluate the work of the project when deciding upon its continuation. Certain aspects of the reflection data are under further study and may require the addition of a correction factor. Current studies imply that the tissues of the eye are affected by the osmotic pressure of the solution in which they are immersed and that after a period of immersion their acoustic impedances show measurable changes. Experiments are currently in progress to substantiate or refute this observation. If this observation should be substantiated one may expect some minor errors in predicting tissue interface reflections on the basis of measurements made on isolated tissues. This phenomena might permit one to study osmotic and diffusion processes in the intact eye. The absorption data is accurate because the energy loss due to reflection is too small to be significant in these measurements. Obviously, certain corrections may have to be made in the final text, based on the findings of the corrected data. |
Title |
The atenuation of ultrasound in biological fluids. |
Author |
Narayana PA, Ophir J,Maklad NF. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1984 |
Abstract |
We have measured the ultrasonic attenuation parameters alpha o and n of several biological fluids in vitro in the frequency range 2.8-6.8 MHz, using frequency shift and/or a sinc (.) sidelobe ratio technique. The parameters αo and n describe the frequency-dependent attenuation via a power-law model, i.e.,α(f)=αofn, where f is frequency. The samples investigated were blood, pus, cyst fluid, bile, and infected hematoma. It was found that the values of αo span approximately the range between 0.03-0.3 dB cm-1MHz-n, and values of n range from about 1.1-1.3. |
Title |
The attenuation of ultrasound in dilute polymeric fiber suspensions. |
Author |
Habeger CC. |
Journal |
J Acoust Soc Am |
Volume |
|
Year |
1982 |
Abstract |
Experimental data for the attenuation of ultrasound by dilute fiber suspensions are presented. Measurements are taken from 0.6 to 10 MHz using rayon, polyester, and nylon fibers with radii in the 7- to 120-?m range. A theory of attenuation due to isolated, infinite, cylindrical inclusions in a fluid is developed. Theory and experiment are found to be in good agreement. |
Title |
The benefit of ultrasound imaging in evaluation of the breast: review of a 3-year clinical program. |
Author |
Harper AP, Kelly-Fry E. |
Journal |
J Indiana State Med Assoc |
Volume |
|
Year |
1981 |
Abstract |
no abstract avoidable. |
Title |
The biochemistry of the inner ear and the consequences of treatment by ultrasound. |
Author |
Hughes DE, Chou JT. |
Journal |
Acta Otolaryngol |
Volume |
|
Year |
No date available. |
Abstract |
No abstract available. |
Title |
The biological effects of ultrasound. |
Author |
Stratmeyer ME, Christman CL. |
Journal |
Women Health |
Volume |
|
Year |
1982 |
Abstract |
In summary, there are many deficiencies and gaps in the current data base for ultrasound-induced bioeffects. More information is needed on the effects of low intensity ultrasound, the effects of pulsed ultrasound, the relationship between.peak intensities and average intensities of pulsed ultrasound, the possibility of cumulative effects, and the possibility of long-term effects. Also, very little of the data, either positive or negative, has been verified by other laboratories. Although.there is presently no evidence to indicate that diagnostic ultrasound involves a significant risk, the evidence is insufficient to justify an unqualified acceptance of safety. The potential for acute adverse effects has not been systematically explored, and the potential for delayed effects has been virtually ignored. Because of the difficulties involved in searching for and defining potential risks from exposure to low levels of chemicals, radiation, or other forms of energy, it is unreasonable to expect that in the near future, the degree of risk, if any, will be clearly defined for diagnostic ultrasound. As in other areas (e.g., the effects of ionizing radiation) no single study, epidemiological or experimental, can accomplish this goal. In the meantime, a prudent public health policy calls for judicious use of diagnostic ultrasound, using it only when diagnostic benefits to patients are indicated, and keeping any exposure to diagnostic ultrasound as low as practicable, consistent with its intended purpose. |
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