Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published April 1, 2007 | Published
Journal Article Open

Ultrasound-modulated optical tomography with intense acoustic bursts


Ultrasound-modulated optical tomography (UOT) detects ultrasonically modulated light to spatially localize multiply scattered photons in turbid media with the ultimate goal of imaging the optical properties in living subjects. A principal challenge of the technique is weak modulated signal strength. We discuss ways to push the limits of signal enhancement with intense acoustic bursts while conforming to optical and ultrasonic safety standards. A CCD-based speckle-contrast detection scheme is used to detect acoustically modulated light by measuring changes in speckle statistics between ultrasound-on and ultrasound-off states. The CCD image capture is synchronized with the ultrasound burst pulse sequence. Transient acoustic radiation force, a consequence of bursts, is seen to produce slight signal enhancement over pure ultrasonic-modulation mechanisms for bursts and CCD exposure times of the order of milliseconds. However, acoustic radiation-force-induced shear waves are launched away from the acoustic sample volume, which degrade UOT spatial resolution. By time gating the CCD camera to capture modulated light before radiation force has an opportunity to accumulate significant tissue displacement, we reduce the effects of shear-wave image degradation, while enabling very high signal-to-noise ratios. Additionally, we maintain high-resolution images representative of optical and not mechanical contrast. Signal-to-noise levels are sufficiently high so as to enable acquisition of 2D images of phantoms with one acoustic burst per pixel.

Additional Information

© 2007 Optical Society of America. Received 12 June 2006; revised 4 October 2006; accepted 10 October 2006; posted 12 October 2006 (Doc. ID 71876); published 13 March 2007. We thank Sava Sakadžić for fruitful discussions. We acknowledge funding from the National Institutes of Health R21/R33 CA094267.

Attached Files

Published - ao-46-10-1615.pdf


Files (696.2 kB)
Name Size Download all
696.2 kB Preview Download

Additional details

August 19, 2023
October 23, 2023