A New Rebinning Reconstruction Method for the Low Dose CT Scanners with Flying Focal Spot

This paper presents an original approach to the image reconstruction problem for spiral CT scanners where the multi-source and/or the Flying Focal Spot (FFS) technology is implemented. The geometry of those scanners causes problems for computed tomography systems based on traditional (FDK) reconstruction methods. Therefore, we propose an original rebinning strategy, where does not occur the problem of non-equiangular X-rays. It is possible to implement this approach in all three types of CT scanners (only Multi-Source, only Flying Focal Spot, mixed Multi-Source with Flying Focal Spot). This approach is divided into two blocks (rebinning and iterative reconstruction procedure). This method is based on statistical model-based iterative reconstruction (MBIR), where the reconstruction problem is formulated as a shift-invariant system (a continuous-to-continuous data model). Our method allows for reducing the X-ray dose absorbed by patients during examinations. The most significant feature of the proposed method is the possibility of parallel implementation using the various GPU graphic card - what we have done for the NVIDIA graphic card. This fact resulted in the acceleration of the calculation and the significantly shortened time for the first reconstructed image.