Acoustic radiation force in vivo: A mechanism to assist targeting of microbubbles

Paul Dayton, Alexander Klibanov, Gary Brandenburger, Kathy Ferrara

Research output: Contribution to journalArticlepeer-review

258 Scopus citations


The goal of targeted imaging is to produce an enhanced view of physiological processes or pathological tissue components. Contrast agents may improve the specificity of imaging modalities through selective targeting, and this may be particularly significant when using ultrasound (US) to image inflammatory processes or thrombi. One means of selective targeting involves the attachment of contrast agents to the desired site with the use of a specific binding mechanism. Because molecular binding mechanisms are effective over distances on the order of nanometers, targeting effectiveness would be greatly increased if the agent is initially concentrated in a particular region, and if the velocity of the agent is decreased as it passes the potential binding site. Ultrasonic transmission produces a primary radiation force that can manipulate microbubbles with each acoustic pulse. Observations demonstrate that primary radiation force can displace US contrast agents from the center of the streamline to the wall of a 200-μm cellulose vessel in vitro. Here, the effects of radiation force on contrast agents in vivo are presented for the first time. Experimental results demonstrate that radiation force can displace a contrast agent to the wall of a 50-μm blood vessel in the mouse cremaster muscle, can significantly reduce the velocity of flowing contrast agents, and can produce a reversible aggregation. Acoustic radiation force presents a means to localize and concentrate contrast agents near a vessel wall, which may assist the delivery of targeted agents. Copyright (C) 1999 World Federation for Ultrasound in Medicine and Biology.

Original languageEnglish (US)
Pages (from-to)1195-1201
Number of pages7
JournalUltrasound in Medicine and Biology
Issue number8
StatePublished - Oct 1999
Externally publishedYes


  • Bjerknes force
  • Contrast agent
  • Drug delivery
  • Microbubble
  • Radiation force
  • Targeted imaging
  • Ultrasound
  • Ultrasound imaging

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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