FBP reconstruction of cone-beam data acquired with a vertex path containing a circle

The paper presents a reconstruction algorithm for cone-beam (CB) data acquired with a vertex path which consists of a circle and of a complementary path such that Tuy's (1983) data sufficiency condition is fulfilled. The algorithm is based on the CB filtered-backprojection method of Defrise and Clack (1994), with an appropriate handling of redundancy to reduce the processing of the circle data to a stationary 2D filtering. The method is similar to a previous algorithm of Kudo and Saito (1994), and it also admits reconstruction from truncated data. However, the use of a 2D filter for the circle data instead of a 1D ramp filter avoids singularities in the filtered projections.