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Updated: Jun 23, 2026
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Multi-timescale Microscopy Methods for the Characterization of Fluorescently-labeled Microbubbles for Ultrasound-Triggered Drug Release
Published on: June 12, 2021
Reflection from bound microbubbles at high ultrasound frequencies
Olivier Couture1, Michael R Sprague, Emmanuel Cherin
1Imaging Research, Sunnybrook Health Sciences Centre/Department of Medical Biophysics, University of Toronto, Toronto, Canada. olicou@gmail.com
Summary
This study shows how microbubbles attached to a surface enhance ultrasound reflection. This finding helps optimize ultrasound imaging for targeted contrast agents in research.
Area of Science:
- Biomedical Engineering
- Acoustics
- Medical Imaging
Background:
- Targeted contrast agents and ultrasound imaging are increasingly used for in vivo biomarker assessment in animal models.
- Understanding ultrasound echoes from cell-bound contrast agents is crucial for advancing these applications.
Purpose of the Study:
- To investigate and quantify the ultrasound reflection enhancement caused by microbubbles bound to a surface.
- To develop a predictive model for ultrasound echoes from microbubble-covered surfaces.
Main Methods:
- Measured ultrasound reflection enhancement using microbubbles on a gelatin surface at high frequency (40 MHz) and low pressure.
- Applied a linear approximation due to low acoustic pressure.
- Developed and validated a multiple scattering model for predicting reflection coefficients.
Main Results:
- Reflection coefficient increased with microbubble density, reaching saturation at 0.9 with 35% surface coverage.
- The multiple scattering model accurately predicted reflection coefficients, even at high surface densities.
Conclusions:
- The study quantifies reflection enhancement by surface-bound microbubbles.
- A multiple scattering model can predict ultrasound echoes from targeted contrast agents.
- Results aid in optimizing high-frequency ultrasound sensitivity for targeted contrast agents.
