Reordering Schemes for Multiple-Rotation Fan-Beam CT Scanner

The number of detectors in a fan-beam CT scanner can be substantially decreased if a multiple-rotation data collection mode is used to provide appropriate spatial resolution. The efficiency of multiple-rotation schemes using a detector offset combined with angular shift of the detectors in each cycle for projection space filling is examined. It is shown that in reordering into parallel projections, angular interpolation can be avoided if an appropriate angular offset of the source with respect to the axis of a fan can be made in each cycle. To achieve even spacing of rays at the ends of the reordered parallel projections, the shifted positions of each detector must be symmetrical with respect to the position of the detector in the original symmetric fan. Results of the computer simulation are presented.