FDK Half-Scan with a Heuristic Weighting Scheme on a Flat Panel Detector-Based Cone Beam CT (FDKHSCW)

摘要

A cone beam circular half-scan scheme is becoming an attractiveimaging method in cone beam CT since it improves the temporalresolution. Traditionally, the redundant data in the circularhalf-scan range is weighted by a central scanning plane-dependentweighting function; FDK algorithm is then applied on the weightedprojection data for reconstruction. However, this scheme stillsuffers the attenuation coefficient drop inherited with FDK whenthe cone angle becomes large. A new heuristic cone beamgeometry-dependent weighting scheme is proposed based on the ideathat there exists less redundancy for the projection data awayfrom the central scanning plane. The performance of FDKHSCW schemeis evaluated by comparing it to the FDK full-scan (FDKFS) schemeand the traditional FDK half-scan scheme with Parker's fan beamweighting function (FDKHSFW). Computer simulation is employed andconducted on a 3D Shepp-Logan phantom. The result illustrates acorrection of FDKHSCW to the attenuation coefficient drop in theoff-scanning plane associated with FDKFS and FDKHSFW whilemaintaining the same spatial resolution.