title: Laser-nucleated acoustic cavitation in focused ultrasound.
abstract: Acoustic cavitation can occur in therapeutic applications of high-amplitude focused ultrasound. Studying acoustic cavitation has been challenging, because the onset of nucleation is unpredictable. We hypothesized that acoustic cavitation can be forced to occur at a specific location using a laser to nucleate a microcavity in a pre-established ultrasound field. In this paper we describe a scientific instrument that is dedicated to this outcome, combining a focused ultrasound transducer with a pulsed laser. We present high-speed photographic observations of laser-induced cavitation and laser-nucleated acoustic cavitation, at frame rates of 0.5×10(6) frames per second, from laser pulses of energy above and below the optical breakdown threshold, respectively. Acoustic recordings demonstrated inertial cavitation can be controllably introduced to the ultrasound focus. This technique will contribute to the understanding of cavitation evolution in focused ultrasound including for potential therapeutic applications.
authors.affiliation: Institute for Medical Science and Technology, The University of Dundee, Dundee DD2 1FD, United Kingdom.
authors.forename: Bjoern
authors.initials: B
authors.lastname: Gerold
authors.forename: Spiros
authors.initials: S
authors.lastname: Kotopoulis
authors.forename: Craig
authors.initials: C
authors.lastname: McDougall
authors.forename: David
authors.initials: D
authors.lastname: McGloin
authors.forename: Michiel
authors.initials: M
authors.lastname: Postema
authors.forename: Paul
authors.initials: P
authors.lastname: Prentice
mesh_terms: D004867:Equipment Design; D007834:Lasers; D055620:Optical Phenomena; D010781:Photography; D014159:Transducers; D014465:Ultrasonics / Q000295:instrumentation*