3-D RECONSTRUCTION OF THE HEART FROM FEW PROJECTIONS: A PRACTICAL IMPLEMENTATION OF THE MCKINNON-BATES ALGORITHM.

A method was implemented for improving the quality (by reducing artifacts) of images reconstructed from small numbers of projections. The technique is based on an algorithm originally proposed by C. G. McKinnon and R. H. T. Bates and includes enhancements suggested by P. B. Heffernan and R. A. Robb. Emphasis is on practical aspects of algorithm implementation, including important noise-suppressing refinements not previously incorporated into the algorithm. The efficacy of the method is demonstrated using actual X-ray projection data of the intact beating heart recorded with the Mayo Clinic's dynamic spatial reconstructor. The implications of improved 'stop-action' reconstruction of the heart are considered in the context of additional objectives, including automatic object recognition and definition, and improved four-dimensional reconstruction of the beating heart.