Abstract

Acousto-optic imaging is a new hybrid technique that combines ultrasound with diffuse light to achieve deep-tissue imaging of optical properties with the spatial resolution of ultrasound. In this technique, the sample is simultaneously insonified by an ultrasound beam and illuminated with a laser source. The ultrasound modulates the optical field in the interaction region, and detection of the modulated optical field gives an indication of the strength of the AO interaction. We have previously demonstrated that a photorefractive crystal (PRC) based optical detection system can be used to detect the AO response generated using pulsed ultrasound from a commercial medical scanner (Analogic AN2300) in vitro. The previous system operated at an optical wavelength of 532 nm, where high optical scattering limits the imaging depth. In addition, the previous system used a BSO photorefractive crystal with response time insufficient to respond to physiological motion. In order to overcome these limitations, a new AO imaging system operating in the near-infrared (NIR) wavelength range using a GaAs photorefractive crystal has been developed. We demonstrate that the response time of the GaAs PRC can be on an order of 1 ms, which is sufficient to overcome speckle decorrelation and is thus suitable for in vivo measurements. Preliminary experimental results demonstrating the detection of an optical absorber in a highly scattering tissue phantom using the NIR acousto-optic system are presented. Work supported in part by CenSSIS, the Center for Subsurface Sensing and Imaging Systems, under the Engineering Research Centers Program of the National Science Foundation (Award Number EEC-9986821).

Notes

Poster presented at the 2006 Thrust R1A Nonlinear and Dual Wave Probes Conference

Keywords

Acousto-Optic Imaging, Near Infrared, ultrasound, deep-tissue, PRC, NIR, GaAs

Subject Categories

Diagnostic imaging

Disciplines

Biomedical Engineering and Bioengineering

Publisher

Bernard M. Gordon Center for Subsurface Sensing and Imaging Systems (Gordon-CenSSIS)

Publication Date

2006

Rights Holder

Bernard M. Gordon Center for Subsurface Sensing and Imaging Systems (Gordon-CenSSIS)


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