Effects of acoustic radiation force and shear waves for absorption and stiffness sensing in ultrasound modulated optical tomography.
Author(s)
Li, R
Elson, DS
Dunsby, C
Eckersley, R
Tang, MX
Type
Journal Article
Abstract
Ultrasound-modulated optical tomography (UOT) combines optical contrast with ultrasound spatial resolution and has great potential for soft tissue functional imaging. One current problem with this technique is the weak optical modulation signal, primarily due to strong optical scattering in diffuse media and minimal acoustically induced modulation. The acoustic radiation force (ARF) can create large particle displacements in tissue and has been shown to be able to improve optical modulation signals. However, shear wave propagation induced by the ARF can be a significant source of nonlocal optical modulation which may reduce UOT spatial resolution and contrast. In this paper, the time evolution of shear waves was examined on tissue mimicking-phantoms exposed to 5 MHz ultrasound and 532 nm optical radiation and measured with a CCD camera. It has been demonstrated that by generating an ARF with an acoustic burst and adjusting both the timing and the exposure time of the CCD measurement, optical contrast and spatial resolution can be improved by ~110% and ~40% respectively when using the ARF rather than 5 MHz ultrasound alone. Furthermore, it has been demonstrated that this technique simultaneously detects both optical and mechanical contrast in the medium and the optical and mechanical contrast can be distinguished by adjusting the CCD exposure time.
Date Issued
2011-04-11
Citation
Opt Express, 2011, 19 (8), pp.7299-7311
ISSN
1094-4087
Publisher
Optical Society of America
Start Page
7299
End Page
7311
Journal / Book Title
Opt Express
Volume
19
Issue
8
Copyright Statement
© 2011 Optical Society of America
Description
31/07/12 MEB. Publisher permits published version to be added
Identifier
http://www.ncbi.nlm.nih.gov/pubmed/21503041
PII: 211482
Subjects
Acoustics
Contrast Media
Equipment Design
Image Enhancement
Lasers
Materials Testing
Optics and Photonics
Phantoms, Imaging
Tomography, Optical
Ultrasonics
Notes
PubMed ID: 21503041
Coverage Spatial
United States