IMPROVED TOMOGRAPHIC RECONSTRUCTION IN SEVEN-PINHOLE IMAGING.

The authors' discuss whether the potentialities of seven-pinhole (7P) tomography have been fully investigated. The reconstruction problem is formulated in mathematical terms; both a continuous version and a discrete version of the problem are presented. Then it is argued that feasible reconstruction methods should be sought in the class of discrete iterative techniques. Up to now, reconstruction of 7P images has been performed almost exclusively on the basis of the SMART algorithm. To answer the question as to whether this algorithm is the best reconstruction method for this application, it is compared to two other iterative techniques, SIRT (to which SMART bears some similarities) and a modified version of ART3. Furthermore, a new operator is introduced to postprocess the reconstructed tomograms. Finally, it is shown that the ART3-based reconstruction algorithm, extended with the postreconstruction operator, renders it worthwhile to reconsider the use of 7P tomography as a standard clinical imaging technique for the heart.