Nonlinear and linear propagation of diagnostic ultrasound pulses

Filipczyński, L.; Kujawska, T.; Tymkiewicz, R.; Wójcik, Janusz

doi:10.1016/s0301-5629(98)00174-4

Cited by 25 publications

(4 citation statements)

References 11 publications

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“…However, it is impossible to speak here of stationary heat effects. The some results of numerical and experimental applications of the formulas presented here were published in [11,12]. Good agreement between and observations is observed -Fig.…”

Section: Discussionsupporting

confidence: 74%

Dispersion and Energy Losses

Wójcik

2003

SSP

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In the present paper, the energy effects accompanying a strong sound disturbance of a medium are analyzed. The waves may be, in time, periodic -continuous or pulsed -or have the form of single pulses. The description is based on the continuous medium equations in potential approximation. The Fourier analysis, elements of the theory of linear operators and analytical functions are applied. A general method is given for the construction of the dispersion operator in the domain of space-time coordinates ( , )x t , to which the small-signal absorption coefficient corresponds. The connection between the absorption operator and visco-elastic components of the stress tensor is given. The relations between absorption operators in the space and time domains are shown. It is demonstrated that in nonlinear interactions, where terms of such type -nonlinear function of pressure -dominate, the power (energy) of the disturbance is conserved. Just as in the linear notation, the only reason why the total power (energy) changes is linear absorption, but that one which occurs under the conditions of nonlinear propagation. In consequence, the equations of power (and energy) balance of the disturbance have the same formal shape in nonlinear and linear descriptions. The equations provide a theoretical basis for different, easier and more accurate methods than those used previously for numerical and experimental determination, of, e.g., the power density of heat sources generated by sound.

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Section: Discussionsupporting

confidence: 74%

Dispersion and Energy Losses

Wójcik

2003

SSP

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“…One approach has been to compare the hydrophone response to that predicted from theoretical nonlinear field calculations [98], [99]. In a more direct approach, TDS has been used to calibrate a membrane hydrophone from 1-40 MHz, and the maximum difference from an interferometric calibration of the same hydrophone was 1.3 dB [100].…”

Section: Hydrophone Calibration At High Frequenciesmentioning

confidence: 99%

Progress in medical ultrasound exposimetry

Harris

2005

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

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Biomedical applications of ultrasound have experienced tremendous growth over the past 50 years. Early work in thermal therapy and surgery soon was followed by diagnostic imaging and Doppler. Because patient safety was an important issue from the beginning, the study of methods for measuring exposure levels, and their relationship to possible biological effects, paralleled the growth of the various therapeutic and diagnostic techniques. The diverse conditions of use have presented a range of exposure measurement challenges, and the sensors and techniques used to evaluate ultrasound fields have had to evolve as new or expanded clinical applications have emerged. In this paper some of the more notable of these developments are presented and discussed. Topics covered include devices and techniques, methods of calibration, progress in standardization, and current problem areas, including the effects of nonlinear propagation. Some early methods are described, but emphasis is given to more recent work applicable to present and future uses of ultrasound in medicine and biology.

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“…An important parameter required in these models is the attenuation coefficient in the medium of interest. In addition, a number of models (Christopher and Parker 1991;Filipczynski et al 1999;Cahill et al 2002;Cahill and Humphrey 2000;Kharin and Vince 2004;Tjotta and Tjotta 1980;Zemp et al 2003) now exist that predict nonlinear pressure fields obtained from diffractive sources and the generation of harmonics that occurs in these fields. In these models, knowledge of the frequency dependence of the attenuation coefficient is required to characterize the absorption of energy in the higher harmonics.…”

Section: Introductionmentioning

confidence: 99%