In medical applications of high intense focused ultrasound the mechanism of interaction between ultrasound waves and cavitation bubbles is responsible for several therapeutic effects as well as for undesired side effects. Based on a two-phase continuum approach for bubbly liquids, in this paper a numerical model is presented to simulate these interactions. The numerical results demonstrate the influence of the cavitation bubble cloud on ultrasound propagation. In the case of a lithotripter pulse an increased bubble density leads to significant changes in the tensile part of the pressure waveform. The calculations are verified by measurements with a fiber optical hydrophone and by experimental results of the bubble cloud dynamics.
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http://dx.doi.org/10.1016/j.ultras.2006.07.006 | DOI Listing |
Phys Med Biol
January 2025
Department of Electrical and Electronic Engineering, The University of Hong Kong, Chow Yei Ching 506, Hong Kong, 999077, HONG KONG.
. The propagation speed of a shear wave, whether externally or internally induced, in biological tissues is directly linked to the tissue's stiffness. The group shear wave speed (SWS) can be estimated using a class of time-of-flight (TOF) methods in the time-domain or phase speed-based methods in the frequency domain.
View Article and Find Full Text PDFSci Rep
January 2025
Institute of Molecular and Clinical Ophthalmology Basel (IOB), Mittlere Strasse 91, 4031, Basel, Switzerland.
The eye and the heart are two closely interlinked organs, and many diseases affecting the cardiovascular system manifest in the eye. To contribute to the understanding of blood flow propagation towards the retina, we developed a method to acquire electrocardiogram (ECG) coupled time-resolved dynamic optical coherence tomography (OCT) images. This method allows for continuous synchronised monitoring of the cardiac cycle and retinal blood flow dynamics.
View Article and Find Full Text PDFThyroid cytopathology, particularly in cases of atypia of undetermined significance/follicular lesions of undetermined significance (AUS/FLUS), suffers from suboptimal sensitivity and specificity challenges. Recent advancements in digital pathology and artificial intelligence (AI) hold promise for enhancing diagnostic accuracy. This systematic review included studies from 2000 to 2023, focusing on diagnostic accuracy in AUS/FLUS cases using AI, whole slide imaging (WSI), or both.
View Article and Find Full Text PDFUltrasonics
December 2024
School of Mechatronic & Automation Engineering, Shanghai University, Shanghai 200444, China; Key Laboratory of Silicate Cultural Relics Conservation (Shanghai University), Ministry of Education, China. Electronic address:
Fiber reinforced polymer composites (FRPs) are essential for various industrial fields, but wrinkles inside will greatly reduce their mechanical properties. Full-matrix capture (FMC) is a popular data structure for ultrasonic phased array imaging in composites. However, such structure may lead to data redundancy and noise interference.
View Article and Find Full Text PDFUltrasonics
December 2024
NDT&E Laboratory, Dalian University of Technology, Dalian 116085, China. Electronic address:
Ultrasonic time-of-flight diffraction (TOFD) technique is applied to non-destructive testing in engineering, but the dead zone influences its applicable range. Alternative TOFD techniques adopt the indirect diffracted waves having long propagation times to decouple from the lateral wave and detect near-surface defects. It should be noted that the applicability of these diffracted waves varies with parameter conditions employed for detection, e.
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