Studies of the cavitational effects of clinical ultrasound by sonoluminescence: 3. Cavitation from pulses a few microseconds in length

Abstract

Sonoluminescence can readily be seen when aerated water is insonated with continuous wave therapeutic ultrasound at room temperature but is not easily observed when short pulses of diagnostic ultrasound are used. In this work an ultrasound generator, operating in the region of 1 MHz and capable of producing pulses of different length and repetition rate, was used for insonation. The pulse repetition rate of the ultrasound was fixed at 1 kHz since this is characteristic of diagnostic machines, and a series of thresholds for sonoluminescence was obtained for two transducers, one therapeutic and one diagnostic, as the number of cycles in each pulse was varied. Sonoluminescence was observed for pulses of a few cycles, but the ultrasound intensity threshold for onset increased sharply with decreasing pulse iength. Under all conditions tested, sonoluminescence was more readily sustained than initiated. At about 20 cycles per pulse, peak negative pressures of about 400 kPa initiated sonoluminescence. These conditions are well within the range of some regimens for Doppler ultrasound and not far removed from the diagnostic situation.

From Seas to Surgeries, From Babbling Brooks to Baby Scans: The Acoustics of Gas Bubbles in Liquids

“…This facility enabled cavitation, located via its sonoluminescent emissions, to the correlated with cell death 94 , which also occurred preferentially 95 at those antinodes compared to the nodes. Similarly, a temporal example provided data and new theories [96][97][98][99][100] relating to the cavitation hazard (and its suppression) associated with pulsing the field. The pulsing characteristics of biomedical fields present a key component in designing and assessing the hazard associated with that field, although is relevance to the hyperthermia biohazard (tissue heating) has received more attention than its relevance to the risk of cavitation (whether unwanted 105 The ability to correlate a given measure of biohazard (such as the cell death discussed above) with sonoluminescence allows correlation of that parameter with cavitation.…”

Industrial lubricant removal using an ultrasonically activated water stream, with potential application for Coronavirus decontamination and infection prevention for SARS-CoV-2

“…However in order to deliver both the microbubbles, and the ultrasound that excited surface waves on their walls, down a stream of water to the target to be cleaned ( Figure 1), Leighton, with his students and colleagues, needed to address the losses and scattering that would occur in streams of water surrounded by pressure-release acoustic boundaries 47,48 with acoustic pulsing. 15,[49][50][51][52]…”

From Sea to Surgeries, From Babbling Brooks to Baby Scans: Bubble Acoustics at Isvr

“…This facility enabled cavitation, located via its sonoluminescent emissions, to the correlated with cell death 94 , which also occurred preferentially 95 at those antinodes compared to the nodes. Similarly, a temporal example provided data and new theories [96][97][98][99][100] relating to the cavitation hazard (and its suppression) associated with pulsing the field. The pulsing characteristics of biomedical fields present a key component in designing and assessing the hazard associated with that field, although is relevance to the hyperthermia biohazard (tissue heating) has received more attention than its relevance to the risk of cavitation (whether unwanted 105 or desired 106).…”