摘要：A cone beam circular half-scan scheme is becoming an attractive
imaging method in cone beam CT since it improves the temporal
resolution. Traditionally, the redundant data in the circular
half-scan range is weighted by a central scanning plane-dependent
weighting function; FDK algorithm is then applied on the weighted
projection data for reconstruction. However, this scheme still
suffers the attenuation coefficient drop inherited with FDK when
the cone angle becomes large. A new heuristic cone beam
geometry-dependent weighting scheme is proposed based on the idea
that there exists less redundancy for the projection data away
from the central scanning plane. The performance of FDKHSCW scheme
is evaluated by comparing it to the FDK full-scan (FDKFS) scheme
and the traditional FDK half-scan scheme with Parker's fan beam
weighting function (FDKHSFW). Computer simulation is employed and
conducted on a 3D Shepp-Logan phantom. The result illustrates a
correction of FDKHSCW to the attenuation coefficient drop in the
off-scanning plane associated with FDKFS and FDKHSFW while
maintaining the same spatial resolution.
