Acoustic response of microbubbles derived from phase-change nanodroplet

Ken Ichi Kawabata, Rei Asami, Takashi Azuma, Shin Ichiro Umemura

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24 Citations (Scopus)


An in vitro feasibility test for a novel ultrasound therapy using a type of superheated perfluorocarbon droplet, phase-change nanodroplet (PCND), was performed in gel phantoms with the goal of high selectivity and low invasiveness. Measurements of broadband signal emission revealed that a triggering ultrasound pulse (peak negative pressure of 2.4 MPa) reduces the pressure threshold for cavitation induced by a subsequent ultrasound exposure at an order of magnitude from 2.4 to 0.2 MPa. The maximum allowed interval between the two ultrasound exposures for inducing cavitation with 100- and 1,000-cycle triggering ultrasound was about 100 and 500 ms, respectively. The echo signal increases induced by the triggering ultrasound with 100- and 1000-cycles were enhanced and suppressed by the subsequent ultrasound exposure, respectively. This different behavior seemed to be due to the presence of enlarged free bubbles, which should be avoided for the localization of therapeutic effects.

Original languageEnglish
Article number07HF18
JournalJapanese journal of applied physics
Issue number7 PART 2
Publication statusPublished - 2010 Jul 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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