Penalized weighted least-squares image reconstruction for dual energy X-ray transmission tomography.
We present a dual-energy (DE) transmission computed tomography (CT) reconstruction method. It is statistically motivated and features nonnegativity constraints in the density domain. A penalized weighted least squares (PWLS) objective function has been chosen to handle the non-Poisson noise added by amorphous silicon (aSi:H) detectors. A Gauss-Seidel algorithm has been used to minimize the objective function. The behavior of the method in terms of bias/standard deviation tradeoff has been compared to that of a DE method that is based on filtered back projection (FBP). The advantages of the DE PWLS method are largest for high noise and/or low flux cases. Qualitative results suggest this as well. Also, the reconstructed images of an object with opaque regions are presented. Possible applications of the method are: attenuation correction for positron emission tomography (PET) images, various quantitative computed tomography (QCT) methods such as bone mineral densitometry (BMD), and the removal of metal streak artifacts.
Sukovic
P
P
Department of Biomedical Engineering, The University of Michigan, Ann Arbor 48109, USA.
Clinthorne
N H
NH
D000465:Algorithms; D007091:Image Processing, Computer-Assisted; D015900:Radiography, Dual-Energy Scanned Projection; D014056:Tomography, X-Ray / Q000379:methods*