Abstract

Acousto-optic (AO) imaging is a new dual-wave modality 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 by pulsed ultrasound from a commercial medical scanner (Analogic AN2300) in vitro. In order to overcome the limitations of imaging depth and relatively long response time of the former AO imaging system working at an optical wavelength of 532 nm, a new setup 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 the order of 1~10 ms, which is sufficient to overcome speckle decorrelation and is thus suitable for in vivo measurements. Progress towards optimization of the NIR AO imaging system is detailed. In addition, preliminary experimental results demonstrating the detection of an optical absorber in both low and highly scattering tissue phantoms are presented.

Notes

Poster presented at the 2007 Thrust R1A Nonlinear and Dual Wave Probes Conference

Keywords

Near Infrared, acoustic imaging

Subject Categories

Diagnostic imaging

Disciplines

Biomedical Engineering and Bioengineering

Publisher

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

Publication Date

2007

Rights Holder

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

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