A free geometry fan-beam CT for peripheral ROI imaging

lmaging the peripheral part of objects is useful in many applications. Here, we work on a CT system specifically designed for these applications, referred as PROI-FGCT, and focus on its practical reconstruction method. The projection data is truncated and only for a range of limited angles. A direct FBP type reconstruction method for PROI-FGCT is derived. It follows the framework of well-known analytical fan beam reconstruction formula without rebinning. The implementation mainly includes three steps: weighting projections, filtration and weighted back-projection. Computer simulation and a practical experiment are done to validate the method. Experimental results demonstrate that a clear structural ROI image can be obtained with this reconstruction method for a PROI-FGCT.