Patent ID: 7778387

Claim:
A computed tomography reconstruction method, comprising: determining an absorption function of object points in an examination zone with a reconstruction computer using two non-empty sets of filtered projections, wherein for a predetermined odd number m≦a second predetermined odd number n: a first set of filtered projections yields, when back-projected, a first absorption function that contains only contributions of Radon-planes with at most m intersections with the source trajectory; a second set of filtered projections yields, when back-projected, a second absorption function that contains only contributions of Radon-planes with more than m intersections with the source trajectory; and at least one of the sets of filtered projections contains contributions from measuring values outside a n-PI window; and determining a partial derivative of measuring values with respect to an angular position of a radiation source, the measuring values being generated by parallel rays emanating from different radiation source positions; the first and the second set of filtered projections include, for each measuring value, a first and a second filtered value, respectively, wherein: each first and second filtered value corresponds to a weighted sum, with filter factors, of first and second intermediate filtered values, respectively, and each of said intermediate filtered values is the result of filtering the derived measuring values along an associated filtering line with a K-filter; and the absorption function of object points in the examination zone is reconstructed by weighted back-projection of the first and second filtered values.