Abstract
Vibro-acoustography (VA) is an imaging technique that uses the dynamic (oscillatory) radiation force of two continuous-wave (CW) ultrasound to image objects at low frequency (within the kHz range). In this technique, the dynamic radiation force is created by means of a confocused transducer emitting two ultrasound beams at slightly-shifted frequencies f 1 and f 2 = f 1 + Δ f. It has been demonstrated previously that high-resolution images of various types of inclusions and tissues can be obtained using this technique. However, if the targeted object reflects ultrasound directly back to the transducer, standing waves are produced that result in an artifact in the VA image. The goal of this study is to remove the standing wave artifact and improve VA images by means of a new process called chirp imaging. The procedure consists of sweeping the frequencies of the primary ultrasound beams in a selected bandwidth while keeping Δ f constant during the sweep. The chirp image is produced by averaging the amplitude of the acoustic emission produced during the sweep. Vibro-acoustography chirp imaging experiments are performed on a stainless-steel sphere attached to a latex sheet in a tank of degassed water. The resulting chirp images demonstrate remarkable reduction of the standing wave artifact compared to the "fixed frequency"VA images.
Original language | English (US) |
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Pages (from-to) | 1249-1255 |
Number of pages | 7 |
Journal | IEEE transactions on medical imaging |
Volume | 24 |
Issue number | 10 |
DOIs | |
State | Published - Oct 2005 |
Keywords
- Acoustic emission
- Chirp imaging
- Dynamic radiation force
- Standing wave
- Ultrasound imaging
- Vibro-acoustography
ASJC Scopus subject areas
- Software
- Radiological and Ultrasound Technology
- Computer Science Applications
- Electrical and Electronic Engineering