Enhancement of ultrasonic absorption by microbubbles for therapeutic application

Use of a microbubble agent to increase the effects of high intensity focused ultrasound on liver tissue

“…With regard to the mechanism by which microbubbles in the ultrasound field cause heating, two factors may be involved: heating by oscillation or explosion of microbubble contrast agents exposed to HIFU, and cavitation bubbles generated by HIFU exposure [16][17][18][19][26][27][28]. Although the presence of the microbubble agent was associated with higher temperatures and more tissue damage, it is not sure how much of the differences between groups to attribute to cavitation and how much to attribute to microbubble oscillation.…”

“…Recently, a report was published regarding the benefits of microbubbles in HIFU therapy against renal tissue [15]. In the field of engineering, we and others reported on the heating effect of microbubbles in an ultrasound field in vitro [16][17][18][19].…”

Optimal dosage of ultrasound contrast agent for ultrasound surgery: Thermal effect of linear plane wave

“…absorption is approximately one order of magnitude larger than scattering by a microbubble whose size is approximately the resonance size or smaller [6]. Therefore, the scattering component of attenuation was assumed to be small and negligible.…”

“…Numerous studies have demonstrated enhancement of ultrasound surgical effects with the presence of ultrasound contrast agent (UCA) [1][2][3][4][5][6]. Low amplitude oscillation of UCA in acoustic field increases thermal deposition [5,6].…”

“…Low amplitude oscillation of UCA in acoustic field increases thermal deposition [5,6]. UCA can also nucleate cavitation, so that a combination of mechanical and thermal damage can be induced at a highly localized area even at a low power level of ultrasound [2][3][4].…”