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We have constructed a near-real-time combined imager suitable for simultaneous ultrasound and near-infrared diffusive light imaging and coregistration. The imager consists of a combined hand-held probe and the associated electronics for data acquisition. A two-dimensional ultrasound array is deployed at the center of the combined probe, and 12 dual-wavelength laser source fibers (780 and 830 nm) and 8 optical detector fibers are deployed at the periphery. We have experimentally evaluated the effects of missing optical sources in the middle of the combined probe on the accuracy of the reconstructed optical absorption coefficient and assessed the improvements of a reconstructed absorption coefficient with the guidance of the coregistered ultrasound. The results have shown that, when the central ultrasound array area is in the neighborhood of 2 cm x 2 cm, which corresponds to the size of most commercial ultrasound transducers, the optical imaging is not affected. The results have also shown that the iterative inversion algorithm converges quickly with the guidance of a priori three-dimensional target distribution, and only one iteration is needed to reconstruct an accurate optical absorption coefficient. OCIS codes: 170.0170, 170.3010, 170.5270, 170.7170, 170.3830.

Coherent artifacts in optical coherence tomography (OCT) images can severely degrade image quality by introducing false targets if no targets are present at the artifact locations. Coherent artifacts can also add constructively or destructively to the targets that are present at the artifact locations. This constructive or destructive interference will result in cancellation of the true targets or in display of incorrect echo amplitudes of the targets. We introduce the use of a nonlinear deconvolution algorithm, CLEAN, to cancel coherent artifacts in OCT images of extracted human teeth. The results show that CLEAN can reduce the coherent artifacts to the noise background, sharpen the air-enamel and enamel-dentin interfaces, and improve the image contrast. OCIS codes: 170.4500, 170.3880, 170.3890, 170.1850.