Affiliations: Department of Physics and Astronomy, University of
Manitoba, Winnipeg, Manitoba, Canada | Medical Physics, CancerCare Manitoba, Winnipeg,
Manitoba, Canada | Department of Radiology, University of Manitoba,
Winnipeg, Manitoba, Canada
Abstract: This work presents a first generation incoherent scatter CT (ISCT)
hybrid (analytic-iterative) reconstruction algorithm for accurate ρ_{e} imaging
of objects with clinically relevant sizes. The algorithm
reconstructs quantitative images of ρ_{e} within a few iterations, avoiding the
challenges of optimization based reconstruction algorithms while addressing the
limitations of current analytical algorithms. A 4π
detector is conceptualized in order to address the issue of directional
dependency and is then replaced with a ring of detectors which detect a
constant fraction of the scattered photons. The ISCT algorithm corrects for the
attenuation of photons using a limited number of iterations and filtered back
projection (FBP) for image reconstruction. This results in a hybrid
reconstruction algorithm that was tested with sinograms generated by Monte
Carlo (MC) and analytical (AN) simulations. Results show that the ISCT
algorithm is weakly dependent on the ρ _{e} initial
estimate. Simulation results show that the proposed algorithm reconstruct
ρ _{e} images with a mean error of
−1% ± 3% for the AN model and
from −6% to −8% for the MC model. Finally, the algorithm is capable
of reconstructing qualitatively good images even in the presence of multiple
scatter. The proposed algorithm would be suitable for in-vivo medical
imaging as long as practical limitations can be addressed.
