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Proceedings Paper

Inertial cavitation in theranostic nanoemulsions with simultaneous pulsed laser and low frequency ultrasound excitation
Author(s): Bastien Arnal; Chen-Wei Wei; Jinjun Xia; Ivan M. Pelivanov; Michael Lombardo; Camilo Perez; Thomas J. Matula; Danilo Pozzo; Matthew O'Donnell
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Paper Abstract

Ultrasound-induced inertial cavitation is a mechanical process used for site-localized therapies such as non-invasive surgery. Initiating cavitation in tissue requires very high intensity focused ultrasound (HIFU) and low-frequencies. Hence, some applications like thrombolysis require targeted contrast agents to reduce peak intensities and the potential for secondary effects. A new type of theranostic nanoemulsion has been developed as a combined ultrasound (US)/photoacoustic(PA) agent for molecular imaging and therapy. It includes a nanoscale emulsion core encapsulated with a layer of gold nanospheres at the water/ oil interface. Its optical absorption exhibits a spectrum broadened up to 1100 nm, opening the possibility that 1064 nm light can excite cavitation nuclei. If optically-excited nuclei are produced at the same time that a low-frequency US wave is at peak negative pressure, then highly localized therapies based on acoustic cavitation may be enabled at very low US pressures. We have demonstrated this concept using a low-cost, low energy, portable 1064 nm fiber laser in conjunction with a 1.24 MHz US transducer for simultaneous laser/US excitation of nanoemulsions. Active cavitation detection from backscattered signals indicated that cavitation can be initiated at very low acoustic pressures (less than 1 MPa) when laser excitation coincides with the rarefaction phase of the acoustic wave, and that no cavitation is produced when light is delivered during the compressive phase. US can sustain cavitation activity during long acoustic bursts and stimulate diffusion of the emulsion, thus increasing treatment speed. An in vitro clot model has been used to demonstrate combined US and laser excitation of the nanoemulsion for efficient thrombolysis.

Paper Details

Date Published: 3 March 2014
PDF: 8 pages
Proc. SPIE 8943, Photons Plus Ultrasound: Imaging and Sensing 2014, 89433E (3 March 2014); doi: 10.1117/12.2042348
Show Author Affiliations
Bastien Arnal, Univ. of Washington (United States)
Chen-Wei Wei, Univ. of Washington (United States)
Jinjun Xia, Univ. of Washington (United States)
Ivan M. Pelivanov, Univ. of Washington (United States)
Moscow State Univ. (Russian Federation)
Michael Lombardo, Univ. of Washington (United States)
Camilo Perez, Univ. of Washington (United States)
Thomas J. Matula, Univ. of Washington (United States)
Danilo Pozzo, Univ. of Washington (United States)
Matthew O'Donnell, Univ. of Washington (United States)


Published in SPIE Proceedings Vol. 8943:
Photons Plus Ultrasound: Imaging and Sensing 2014
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)

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