TITLE:
Image Reconstruction from Fan-Beam Projections without Back-Projection Weight in a 2-D Dynamic CT: Compensation of Time-Dependent Rotational, Uniform Scaling and Translational Deformations
AUTHORS:
A. V. Narasimhadhan, Aman Sharma, Dipen Mistry
KEYWORDS:
Fan-Beam Reconstruction Algorithm; Hilbert Filter; Virtual Acquisition Geometry; Equiangular Detector Geometry; Rotational; Uniform Scaling and Translational Deformation; Position Dependent Back-Projection Weight
JOURNAL NAME:
Open Journal of Medical Imaging,
Vol.3 No.4,
December
9,
2013
ABSTRACT:
In a dynamic CT, the acquired projections are corrupted due to
strong dynamic nature of the object, for example: lungs, heart etc. In this
paper, we present fan-beam reconstruction algorithm without position-dependent
backprojection weight which compensates for the time-dependent translational, uniform
scaling and rotational deformations occurring in the object of interest during
the data acquisition process. We shall also compare the computational cost of
the proposed reconstruction algorithm with the existing one which has position-dependent
weight. To accomplish the objective listed above, we first formulate
admissibility conditions on deformations that is required to exactly
reconstruct the object from acquired sequential deformed projections and then
derive the reconstruction algorithm to compensate the above listed deformations
satisfying the admissibility conditions. For this, 2-D time-dependent
deformation model is incorporated in the fan-beam FBP reconstruction algorithm
with no backprojection weight, assuming the motion parameters being known.
Finally the proposed reconstruction algorithm is evaluated with the motion
corrupted projection data simulated on the computer.