Inverse-geometry CT (IGCT) employs a large area x-ray source array opposite a small area detector array.
The system is expected to provide sub-second volumetric imaging with isotropic resolution and no cone-beam
effects. Due to the large amount of data, it is desirable to have an exact 3D reconstruction algorithm that is
fast. Currently known IGCT algorithms are either slow, due to 3D backprojection, and/or require a reprojection
step, or are inexact. Defrise et al. developed an exact Fourier rebinning algorithm (FORE-J) for 3D PET. This
algorithm first rebins the 3D PET data into in-plane sinograms and then reconstructs the series of axial slices
using any 2D method. FORE-J is fast, exact, and efficiently uses all of the acquired PET data. We modified this
algorithm to adapt it to the IGCT geometry. Experiments were performed using a numerical "Defrise" phantom
consisting of high-intensity discs spaced in z to assess the accuracy of the modified algorithm as well as highlight
any cone-beam effects. A noise simulation was performed to analyze the noise properties of FORE-J and the
modified algorithm. The modified algorithm is very fast and slightly more accurate than the original algorithm
with a very small noise penalty in the central axial slices.
Samuel R. Mazin,
Norbert J. Pelc,
"A fast 3D reconstruction algorithm for inverse-geometry CT based on an exact PET rebinning algorithm", Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65105C (16 March 2007); doi: 10.1117/12.708961; https://doi.org/10.1117/12.708961
Samuel R. Mazin, Norbert J. Pelc, "A fast 3D reconstruction algorithm for inverse-geometry CT based on an exact PET rebinning algorithm," Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65105C (16 March 2007);