Implementations of statistical reconstruction algorithm for CT scanners with flying focal spot

Abstract

This paper presents some practical realizations of image reconstruction methods for spiral cone-beam tomography scanners in which an X-ray tube with a flying focal spot is used. These methods are related to the original formulated 3D statistical model-based iterative reconstruction approach for tomography with flying focal spot. The conception proposed here is based on principles of a statistical model-based iterative reconstruction (MBIR) methodology, where the reconstruction problem is formulated as a shift-invariant system (a continuous-to-continuous data model). We adopted nutating reconstruction-based approaches, i.e. the advanced single slice rebinning methodology (usually applied in CT scanners with X-ray tubes with a flying focal spot), and a procedure compliant with the FDK scheme. We showed that our methods significantly improve the quality of obtained images compared to the traditional FBP algorithms. Consequently, it can allow for a reduction in the x-ray dose absorbed by a patient. Additionally, we show that our approach can be competitive in terms of the time of calculations, especially if we consider commercially used statistical reconstruction systems.