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2 March 2006 Computer simulation of FDK reconstruction with the in-line holographic projection data
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Phase-contrast imaging uses the phase coefficient rather than the attenuation coefficient alone to image objects. Consequently, it may resolve some structures that have similar attenuation coefficients but different phase coefficients as their surroundings. Phase contrast imaging is also an edge-enhanced imaging technique. With this method, the boundary of inside small structures could be easily determined. In this paper, the possibility of incorporating the phase contrast in-line method into the current cone beam CT (CBCT) system was explored. Starting from the interference formula of in-line holography, some mathematical assumptions were made and thus, the terms in the interference formula could be approximately expressed as a line integral that is the requirement for all CBCT algorithms. So, the CBCT reconstruction algorithms, such as the FDK algorithm could be applied for the in-line holographic projections, with some mathematical imperfection. A point x-ray source and a high-resolution detector were assumed for computer simulation. The reconstructions for cone-beam CT imaging were studied. The results showed that all the lesions in the numerical phantom could be observed with an enhanced edge. However, due to the edge-enhancement nature of the inline holographic projection, the reconstructed images had obvious streak artifacts and numerical errors. The image quality could be improved by using a hamming window during the filtering process. In the presence of noise, the reconstructions from the in-line holographic projections showed clearer edges than the normal CT reconstructions did. Finally it was qualitatively illustrated that small cone angle and weak attenuation were preferred in this method.
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Weixing Cai, Ruola Ning, and Dong Yang "Computer simulation of FDK reconstruction with the in-line holographic projection data", Proc. SPIE 6142, Medical Imaging 2006: Physics of Medical Imaging, 61424G (2 March 2006);

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