A new approximate algorithm for image reconstruction in cone-beam spiral CT at small cone-angles

Presents a new approximate algorithm for image reconstruction with cone-beam spiral CT data at relatively small cone-angles. Based on the algorithm of Wang et al. (1993), our method combines a special complementary interpolation with filtered backprojection. The presented algorithm has three main advantages over Wang´s algorithm: (1) It overcomes the pitch limitation of Wang´s algorithm. (2) It significantly improves z-resolution when suitable sampling schemes are applied. (3) It avoids the waste of applied radiation dose inherent to Wang´s algorithm. Usage of the total applied dose is an important requirement in medical imaging. Our method has been implemented on a standard workstation. Reconstructions of computer-simulated data of different phantoms, assuming sampling conditions and image quality requirements typical to medical CT, show encouraging results