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Scientific article
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English

PFOB sonosensitive microdroplets: determining their interaction radii with focused ultrasound using MR thermometry and a Gaussian convolution kernel computation

Published inInternational journal of hyperthermia, vol. 39, no. 1, p. 108-119
Publication date2022
Abstract

Purpose: Micron-sized perfluorocarbon droplet adjuvants to focused ultrasound therapies allow lower applied power, circumvent unwanted prefocal heating, and enhance thermal dose in highly perfused tissues. The heat enhancement has been shown to saturate at increasing concentrations. Experiments were performed to empirically model the saturating heating effects during focused ultrasound.

Materials and methods: The measurements were made at varying concentrations using magnetic resonance thermometry and focused ultrasound by circulating droplets of mean diameter 1.9 to 2.3 µm through a perfused phantom. A simulation was performed to estimate the interaction radius size, empirically.

Results: The interaction radius, representing the radius of a sphere encompassing 90% of the probability for the transformation of acoustic energy into heat deposition around a single droplet, was determined experimentally from ultrasonic absorption coefficient measurements The simulations suggest the interaction radius was approximately 12.5-fold larger than the geometrical radius of droplets, corresponding to an interaction volume on the order of 2000 larger than the geometrical volume.

Conclusions: The results provide information regarding the dose-response relationship from the droplets, a measure with 15% precision of their interaction radii with focused ultrasound, and subsequent insights into the underlying physical heating mechanism.

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Keywords
  • MR thermometry
  • Focused ultrasound
  • Microdroplets
  • Perfluorocarbon emulsions
  • Sonosensitizers
  • Thermal ablation
  • Fluorocarbons
  • High-Intensity Focused Ultrasound Ablation / methods
  • Hydrocarbons, Brominated
  • Magnetic Resonance Imaging / methods
  • Radius
  • Thermometry / methods
Funding
Citation (ISO format)
HOLMAN, Ryan Hawley et al. PFOB sonosensitive microdroplets: determining their interaction radii with focused ultrasound using MR thermometry and a Gaussian convolution kernel computation. In: International journal of hyperthermia, 2022, vol. 39, n° 1, p. 108–119. doi: 10.1080/02656736.2021.2021304
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ISSN of the journal0265-6736
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Technical informations

Creation09/21/2022 3:28:00 PM
First validation09/21/2022 3:28:00 PM
Update time09/04/2023 11:39:10 AM
Status update09/04/2023 11:39:10 AM
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