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Browsing by Author "Cong, Alexander X."

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    Extended interior methods and systems for spectral, optical, and photoacoustic imaging
    (United States Patent and Trademark Office, 2014-10-14)
    The present invention relates to the field of medical imaging. More particularly, embodiments of the invention relate to methods, systems, and devices for imaging, including for tomography-based applications. Embodiments of the invention include, for example, a computed tomography based imaging system comprising: (a) at least one wide-beam gray-scale imaging chain capable of performing a global scan of an object and acquiring projection data relating to the object; (b) at least one narrow-beam true-color imaging chain capable of performing a spectral interior scan of a region of interest (ROI) of and acquiring projection data relating to the object; (c) a processing module operably configured for: (1) receiving the projection data; (2) reconstructing the ROI into an image by analyzing the data with a color interior tomography algorithm, aided by an individualized gray-scale reconstruction of an entire field of view (FOV), including the ROI; and (d) a processor for executing the processing module. The extended interior methods and systems for spectral, optical, and photoacoustic imaging presented in this application can lead to better medical diagnoses by providing images with higher resolution or quality, and can lead to safer procedures by providing systems capable of reducing a patient's exposure time to, and thus quantity of, potentially harmful x-rays. Embodiments of the invention also provide tools for real-time tomography-based analyses.
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    Improving the Accuracy of the Diffusion Model in Highly Absorbing Media
    Cong, Alexander X.; Shen, Haiou; Cong, Wenxiang; Wang, Ge (Hindawi, 2007-08-29)
    The diffusion approximation of the Boltzmann transport equation is most commonly used for describing the photon propagation in turbid media. It produces satisfactory results in weakly absorbing and highly scattering media, but the accuracy lessens with the decreasing albedo. In this paper, we presented a method to improve the accuracy of the diffusion model in strongly absorbing media by adjusting the optical parameters. Genetic algorithm-based optimization tool is used to find the optimal optical parameters. The diffusion model behaves more closely to the physical model with the actual optical parameters substituted by the optimized optical parameters. The effectiveness of the proposed technique was demonstrated by the numerical experiments using the Monte Carlosimulation data as measurements.