Investigation of Inertial Cavitation Induced by Modulated Focused Ultrasound Stimuli

Abstract

A passive cavitation detection setup is used to assess and verify the capability of frequency- and amplitudemodulated ultrasound burst signals on the generation of inertial cavitation. The measurements were conducted with a flowthrough tissue-mimicking phantom with a canal of dc = 1mm in diameter simulating a fine blood vessel. By means of a flow velocity of vf= 50mm/s circulating blood in the cardiovascular system is imitated. Applying signal frequencies from f = 550 − 950 kHz and peak rarefaction pressures in a range from ˆpPRFP ≈ 0.17 − 1.81 MPa, various ultrasound stimuli with alternating signal parameters were investigated in the absence and presence of a talcum-water mixture acting as cavitation nuclei. By evaluating the broadband emissions in the frequency domain and calculating the voltage spectral density Srm, the results can be compared. The findings of the present study demonstrate that each ultrasound stimulus triggers a similar strength of cavitation noise at the same Mechanical Index, representing a certain pressure. Over the whole frequency and Mechanical Index (pressure) range, each ultrasound signal type generates a voltage spectral density from Srm= 0.25 − 2.25 V/ √ Hz.

Precision gas therapy by ultrasound‐triggered for anticancer therapeutics

“…Ultrasound technology is used for diagnostic and therapeutic purposes in the clinical due to its cheap characteristics, deep tissue penetration, safety, non‐invasiveness, and ease of use 47–49 . Regarding uses of ultrasound‐based therapy, it is possible to generate physical effects under the propagation of ultrasound, including acoustic fluid flow, pressure changes, cavitation, and heat therapy 50,51 . And sonication‐responsive therapeutic agents deliver devices demand biocompatible components as carriers, enabling the release or activation of therapeutic drugs by specified protonation, hydration, phase changes, and changes in molecular or supramolecular conformation 52 .…”

“…[47][48][49] Regarding uses of ultrasound-based therapy, it is possible to generate physical effects under the propagation of ultrasound, including acoustic fluid flow, pressure changes, cavitation, and heat therapy. 50,51 And sonicationresponsive therapeutic agents deliver devices demand biocompatible components as carriers, enabling the release or activation of therapeutic drugs by specified protonation, hydration, phase changes, and changes in molecular or supramolecular conformation. 52 During ultrasound irradiation, the ultrasonically generated pressure oscillations affect the homeostasis of the drug delivery, concomitant thermal and mechanical effects are much more prominent for making further configurational changes.…”