In 1990 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, volume 2, pages 1513-1517, Arlington, Virginia, 22-27 October 1990.
Fan beam collimator geometries offer advantages over parallel hole collimator geometries in several areas, but present a major difficulty in the reconstruction. Previous investigators have proposed direct recontruction methods and rebinning of the rays to a parallel hole collimator geometry. These rebinning methods, which use interpolation and distance weighted averaging, assume that the space of projection rays intersecting the object is Euclidean or cylindrical. We have developed a new distance function for projection rays which reflects a different curvature of the projection space. An application to simulated data is presented. While originally designed for SPECT reconstructions, it can be applied to any modality where rebinning of projection rays is needed.