SYSTEM AND METHOD FOR HELICAL CONE-BEAM COMPUTED TOMOGRAPHY WITH EXACT RECONSTRUCTION

摘要

A helical conebeam computed tomography imaging system includes an x-ray source ( 12 ) that produces an x ray conebeam, and an x-ray detector array ( 16 ) that detects the x ray conebeam after passing through an examination region ( 14 ). The x-ray detector array ( 16 ) generates projection data in a detector coordinate system defined with reference to the detector array ( 16 ). A derivative processor ( 60 ) computes a derivative of the projection data with respect to a helix angle of the helical trajectory at fixed projection direction to generate differentiated projection data. A convolution processor ( 64 ) convolves the differentiated projection data with a kernel function to produce filtered projection data. The convolving is performed in the detector coordinate system. A backprojector ( 42, 82 ) backprojects the filtered projection data to obtain an image representation.