Ultrasonic imaging of displacements inside objects induced by continuously applied fluctuating acoustic radiation forces

Hideyuki Hasegawa, Y. Odagiri, H. Kanai

Research output: Contribution to journalConference articlepeer-review

Abstract

One possible way to evaluate acupuncture therapy quantitatively is to measure the change in the elastic property of muscle after application of the therapy. Many studies have been conducted to measure mechanical properties of tissues using ultrasound-induced acoustic radiation force. To assess mechanical properties, strain must be generated in an object. However, a single radiation force is not effective because it mainly generates translational motion when the object is much harder than the surrounding medium. In the present study, two cyclic radiation forces are simultaneously applied to a muscle phantom from two opposite horizontal directions so that the object is cyclically compressed in the horizontal direction. By the horizontal compression, the object is expanded vertically based on its incompressibility. The resultant vertical displacement is measured using another ultrasound pulse. Two ultrasonic transducers for actuation were both driven by the sum of two continuous sinusoidal signals at two slightly different frequencies (1 MHz and (1 M+5) Hz). The displacement of several micrometers in amplitude, which fluctuated at 5 Hz, was measured by the ultrasonic phased tracking method. Increase in thickness inside the object was observed just when acoustic radiation forces increased. Such changes in thickness correspond to vertical expansion due to horizontal compression.

Original languageEnglish
Pages (from-to)6197-6202
Number of pages6
JournalProceedings - European Conference on Noise Control
Publication statusPublished - 2008 Dec 1
Event7th European Conference on Noise Control 2008, EURONOISE 2008 - Paris, France
Duration: 2008 Jun 292008 Jul 4

ASJC Scopus subject areas

  • Acoustics and Ultrasonics
  • Public Health, Environmental and Occupational Health
  • Building and Construction
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Automotive Engineering
  • Aerospace Engineering

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