Nonlinear propagation acoustics of dual-frequency wide-band excitation pulses in a focused ultrasound system

2010 ◽  
Vol 128 (5) ◽  
pp. 2695-2703 ◽  
Author(s):  
Svein-Erik Måsøy ◽  
Øyvind Standal ◽  
Jochen M. Deibele ◽  
Sven Peter Näsholm ◽  
Bjørn Angelsen ◽  
...  
Keyword(s):  
Focused Ultrasound ◽  
Wide Band ◽  
Nonlinear Propagation ◽  
Dual Frequency ◽  
Ultrasound System

Temperature Feedback Control for Hyperthermia of Chest Wall Volumes With Dual-Frequency Ultrasound

1999 ◽  
Author(s):  
Eduardo G. Moros ◽  
William L. Straube ◽  
Robert J. Myerson
Keyword(s):  
Feedback Control ◽  
Chest Wall ◽  
Focused Ultrasound ◽  
Technology Development ◽  
Optimal Parameter ◽  
Heat Removal ◽  
Blood Perfusion ◽  
Dual Frequency ◽  
Temperature Feedback ◽  
Ultrasound System

Abstract Therapeutic temperature distributions during hyperthermia treatments are very difficult to maintain (e.g., 41.5 to 43°C for 45 to 60 min.) due to many heat removal/loss mechanisms. Thermoregulatory responses of the human body are efficacious in preserving and re-establishing normothermic conditions, and are considered to be the main cause of temperature non-uniformities through effected changes in blood perfusion and blood flow in large vessels. From the very beginning of hyperthermia technology development temperature feedback control systems (temperature controllers) have been proposed as a way to counterbalance thermoregulation and improve thermal doses. Only a few controllers, however, have been thoroughly tested numerically, experimentally, and most importantly, clinically. In this paper the proportional-integral-derivative bang-bang (PIDBB) controller of Lin et al. (1990), originally designed for a scanned focused ultrasound system for deep localized hyperthermia, was applied numerically to a scanned dual-frequency planar ultrasound system for chest wall hyperthermia. It was found that PIDBB controller with the optimal parameter values as determined by Lin et al. (1990) performed satisfactorily in controlling temperatures in superficial chest wall volumes.

Dual Frequency Wide Band Cusp Antenna Fed by Coplanar Waveguide

1998 ◽  
Author(s):  
E. A. Soliman ◽  
S. Brebels ◽  
E. Beyne ◽  
G. Vandenbosch
Keyword(s):  
Coplanar Waveguide ◽  
Wide Band ◽  
Dual Frequency

Nonlinear Derating of High-Intensity Therapeutic Ultrasound Beams Using Gaussian Modal Sums

2013 ◽  
Author(s):  
Seyed Ahmad Reza Dibaji ◽  
Matthew R. Myers ◽  
Joshua E. Soneson ◽  
Rupak K. Banerjee
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
High Intensity Focused Ultrasound ◽  
Nonlinear Propagation ◽  
Tissue Temperature ◽  
Medical Procedure ◽  
Pressure Amplitude ◽  
Pressure Trace ◽  
The Difference ◽  
Semi Empirical

High intensity focused ultrasound (HIFU) is a noninvasive medical procedure during which a large amount of energy is deposited in a short duration which causes sudden localized rise in tissue temperature, and ultimately, cell necrosis. In assessing the influence of HIFU on biological tissue, semi-empirical mathematical models can be useful for predicting thermal effects. These models require values of the pressure amplitude in the tissue of interest, which can be difficult to obtain experimentally. One common method for estimating the pressure amplitude in tissue is to operate the HIFU transducer in water, measure the pressure amplitude, then multiply by a scaling factor that accounts for the difference in attenuation between water and tissue. This procedure can be accurate when the ultrasound amplitude is low, and the pressure trace in tissue is proportional to that in water. Because of this proportionality, the procedure for reducing the amplitude from water to tissue is called linear derating. At higher intensities, however, harmonics of the fundamental frequency are generated due to nonlinear propagation effects. Higher harmonics are attenuated differently in water and tissue (Hamilton and Blackstock [1]), and the pressure waves in water and tissue are no longer proportional to one another. Techniques for nonlinearly transforming pressure amplitudes measured in water to values appropriate for tissue are therefore desirable when bioeffects of higher intensity procedures are being studied. These techniques are labeled “nonlinear derating”.

Auto‐tuning network for phased‐array high‐intensity focused ultrasound system

2018 ◽  
Vol 54 (21) ◽  
pp. 1202-1204 ◽  
Author(s):  
Xusheng Wang ◽  
Ming Zhang ◽  
Francis Rodes ◽  
Congjun Cao
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Phased Array ◽  
High Intensity Focused Ultrasound ◽  
Ultrasound System ◽  
Auto Tuning
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