  In projection-based magnetic particle imaging (MPI) with a field-free-line
(FFL) encoding scheme, projection data are usually acquired by moving the FFL
in a zigzag and a difference in the projection data occurs depending on the
scanning direction of FFL, resulting in blurring in the reconstructed images.
In this study, we developed a method for correcting the blur by deconvolution
using a signal-delay constant ({\xi}). The {\xi} value for correction ({\xi}c)
was determined by acquiring projection data in positive and negative directions
and searching for the {\xi} value which minimized the 2-norm between the
deconvolved projection data in the two directions. We validated our method
using a line and A-shaped phantoms for various velocities of FFL (vFFL). The
{\xi}c value correlated linearly with vFFL. The full width at half maximum of
the line phantom decreased significantly after correction of the blur. The
effectiveness of our method was also confirmed by the MPI images of the
A-shaped phantom. These results suggest that our method will be useful for
enhancing the reliability of projection-based MPI.
