Efficacy of perfluorobutane as a phase-change contrast agent for low-energy ultrasonic imaging

Sheeran, Paul S.; Wong, Vincent P.; McFarland, Ryan J.; Ross, William N.; Feingold, Steven; Matsunaga, Terry O.; Dayton, Paul A.

doi:10.1109/ultsym.2010.5935592

Cited by 1 publication

(1 citation statement)

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“…The array was connected to a research platform (Verasonics Vantage 256, Kirkland, WA, USA) to image phantoms at 1000 frames/s during irradiation, by use of a plane wave (0˚, no angle compounding) imaging sequence. The ultrasound center frequency was 9 MHz, and the peak negative pressure of the plane waves was 370 kPa (characterized with a 0.075-mm needle hydrophone, Precision Acoustics, Dorchester, England), well below the threshold for acoustic droplet vaporization (Sheeran et al 2010). The ultrasound radiofrequency (RF) data were beamformed offline using the Verasonics beamformer.…”

Section: Online Ultrasound Imaging and Image Processingmentioning

confidence: 99%

Spatiotemporal Distribution of Nanodroplet Vaporization in a Proton Beam Using Real-Time Ultrasound Imaging for Range Verification

Collado-Lara

Heymans

Rovituso³

et al. 2022

Ultrasound in Medicine & Biology

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The potential of proton therapy to improve the conformity of the delivered dose to the tumor volume is currently limited by range uncertainties. Injectable superheated nanodroplets have recently been proposed for ultrasound-based in vivo range verification, as these vaporize into echogenic microbubbles on proton irradiation. In previous studies, offline ultrasound images of phantoms with dispersed nanodroplets were acquired after irradiation, relating the induced vaporization profiles to the proton range. However, the aforementioned method did not enable the counting of individual vaporization events, and offline imaging cannot provide real-time feedback. In this study, we overcame these limitations using high-frame-rate ultrasound imaging with a linear array during proton irradiation of phantoms with dispersed perfluorobutane nanodroplets at 37˚C and 50˚C. Differential image analysis of subsequent frames allowed us to count individual vaporization events and to localize them with a resolution beyond the ultrasound diffraction limit, enabling spatial and temporal quantification of the interaction between ionizing radiation and nanodroplets. Vaporization maps were found to accurately correlate with the stopping distribution of protons (at 50˚C) or secondary particles (at both temperatures). Furthermore, a linear relationship between the vaporization count and the number of incoming protons was observed. These results indicate the potential of real-time high-frame-rate contrast-enhanced ultrasound imaging for proton range verification and dosimetry.

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Section: Online Ultrasound Imaging and Image Processingmentioning

confidence: 99%