Cone-beam pseudo lambda tomography under FDK framework / 南方医科大学学报

The medical CT scanner is rapidly evolving from the fan-beam mode to the cone-beam geometry mode. In this paper, a new cone-beam pseudo Lambda tomography was proposed based on the Noo's fan beam super-short scan formula and FDK framework. The proposed pseudo-LT algorithm, which avoids the computation of any PI line and any differential operation, has a significant practical implementation, thus leading to the images with quality improvement and reduced artifacts. The results in the simulation studies confirm the observation that the new algorithm can improve the image resolution over the traditional algorithms with noise projection data.

Elimination of direct derivative of the projection data for image reconstruction based on hybrid filter in helical cone-beam CT / 南方医科大学学报

<p><b>OBJECTIVE</b>We present an alternative approach for precise reconstruction of the images from helical cone-beam projections combining Hilbert filter and Ramp filter.</p><p><b>METHODS</b>Based on the Katsevich algorithm framework, the proposed algorithm combined the FDK-type algorithms and Katsevich algorithm for their respective advantages, to completely avoid the direct derivatives with respect to the coordinates on the detector plane.</p><p><b>RESULTS</b>The experimental results validated the accuracy of the new algorithm, and this approach significantly improved the resolution of the reconstructed images with much reduced artifacts.</p><p><b>CONCLUSION</b>The proposed reconstruction formula based on hybrid Hilbert-Ramp filter is an important development of Katsevich reconstruction formula, and the different forms of the Ramp filters can be designed to realize frequency modulation according to the actual clinical application.</p>