Reduction of ultrasound inertial cavitation threshold using bifrequency excitation
ABSTRACT Within the scope of an application to transcutaneous ultrasonic thrombolysis, this study compares inertial cavitation thresholds obtained at the focus of a transducer for two types of ultrasonic excitations: a classical one frequency signal and an excitation combining two slightly different frequencies. A cepstral filtering method is used to measure inertial cavitation activity for these signals. A 30% reduction of the threshold is observed when using bifrequency excitation.
Article: Bubbly cavitating flow generation and investigation of its erosional nature for biomedical applications.[show abstract] [hide abstract]
ABSTRACT: This paper presents a study that investigates the destructive energy output resulting from hydrodynamic bubbly cavitation in microchannels and its potential use in biomedical applications. The research performed in this study includes results from bubbly cavitation experiments and findings showing the destructive effects of bubbly cavitating flow on selected solid specimens and live cells. The bubbles generated by hydrodynamic cavitation are highly destructive at the surfaces of the target medium on which they are carefully focused. The resulting destructive energy output could be effectively used for biomedical treatments, such as destroying kidney stones (renal calculi) or killing cancer cells. Motivated by this potential, the cavitation damage to cancerous cells and material removal from chalk pieces (which possess similar material properties as some kidney stones) was investigated. Our results showed that cavitation could induce damage both on chalk pieces and leukemia/lymphoma cells. We discovered that hydrodynamic cavitation exposure had early and delayed effects on cancer cell survival. Hence, the potential of hydrodynamic bubbly cavitation generated at the microscale for biomedical treatments was revealed using the microchannel configuration as a microorifice (with an inner diameter of 147 μm and a length of 1.52 cm), which acts as the source of bubbly cavitating flows.IEEE transactions on bio-medical engineering 01/2011; 58(5):1337-46. · 2.15 Impact Factor