title: Sono-photoacoustic imaging of gold nanoemulsions: Part II. Real time imaging.
abstract: Photoacoustic (PA) imaging using exogenous agents can be limited by degraded specificity due to strong background signals. This paper introduces a technique called sono-photoacoustics (SPA) applied to perfluorohexane nanodroplets coated with gold nanospheres. Pulsed laser and ultrasound (US) excitations are applied simultaneously to the contrast agent to induce a phase-transition ultimately creating a transient microbubble. The US field present during the phase transition combined with the large thermal expansion of the bubble leads to 20-30 dB signal enhancement. Aqueous solutions and phantoms with very low concentrations of this agent were probed using pulsed laser radiation at diagnostic exposures and a conventional US array used both for excitation and imaging. Contrast specificity of the agent was demonstrated with a coherent differential scheme to suppress US and linear PA background signals. SPA shows great potential for molecular imaging with ultrasensitive detection of targeted gold coated nanoemulsions and cavitation-assisted theranostic approaches.
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States.
authors.forename: Bastien
authors.initials: B
authors.lastname: Arnal
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States.
authors.forename: Chen-Wei
authors.initials: CW
authors.lastname: Wei
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States ; University of Washington, Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, 1013 NE 40th Street, Seattle, WA 98105-6698, United States.
authors.forename: Camilo
authors.initials: C
authors.lastname: Perez
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States.
authors.forename: Thu-Mai
authors.initials: TM
authors.lastname: Nguyen
authors.affiliation: University of Washington, Department of Chemical Engineering, Box 351750, Seattle, WA 98195-1750, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Lombardo
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States ; International Laser Center, Moscow State University, Moscow, Russian Federation.
authors.forename: Ivan
authors.initials: I
authors.lastname: Pelivanov
authors.affiliation: University of Washington, Department of Chemical Engineering, Box 351750, Seattle, WA 98195-1750, United States.
authors.forename: Lilo D
authors.initials: LD
authors.lastname: Pozzo
authors.affiliation: University of Washington, Department of Bioengineering, 616 NE Northlake Place, Seattle, WA 98105, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
keywords: Background suppression; Gold nanoparticles; Nanoemulsion; Non-linear photoacoustics; Photoacoustic cavitation; Vaporization