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16 March 2007 Iterative extended field of view reconstruction
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Incomplete data due to the object extent beyond the scanning field of view (SFOV) is a common problem in computed tomography. In these cases, there are parts of the object to be reconstructed for which only incomplete projections of less than 180o are available. Applying iterative algorithms like algebraic reconstruction technique (ART) or simultaneous algebraic reconstruction Technique (SART) onto the problem of truncated projections can not produce a satisfying solution unless special constraints are used. To regularize the reconstruction algorithm, we extend iterative reconstruction algorithms by introducing information regarding the statistics of the attenuation values of the reconstructed object in terms of the log likelihood function of attenuation values. This information can be taken from the regions of the image still inside the SFOV but close to the region where the object exceeds the SFOV. The information can be utilized in an algebraic reconstruction method by adding a constraint term to the cost function that shall be minimized. Experiments show that for not severely truncated projections, as they are common for CT applications, including this information yields good estimates about the object.
© (2007) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Holger Kunze, Wolfgang Härer, and Karl Stierstorfer "Iterative extended field of view reconstruction", Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65105X (16 March 2007);

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