APPARATUS AND METHOD FOR RECONSTRUCTION OF VOLUMETRIC IMAGES IN A HELICAL SCANNING CONE-BEAM COMPUTED TOMOGRAPHY SYSTEM

An apparatus and method for reconstructing image data for a region are described. A radiation source and an array of detectors located on opposed sides of a region are used to generate scan data for the region from a plurality of diverging radiation beams, i.e., a cone beam. The cone beam scan data for the region are converted into parallel beam scan data. The reordered parallel beam scan data are used to generate projection data related to a set of oblique slices for the region, wherein the oblique slices form a non-perpendicular angle with the longitudinal axis of the region. Convolution is applied to the projection data related to each oblique slice. The image data for the region are then generated by three-dimensional back projection of the convoluted projection data along the paths of the interpolated rays.