REGION-OF-INTEREST IMAGING IN CONE-BEAM 3-D CT

Imaging a sectional region within an object with a detector just big e nough to cover the sectional region-of-interest is analyzed. With othe rwise complete (for small objects) cone beam scanning configurations, some of the Radon data are corrupted by unwanted measurements from out side the region-of-interest, and furthermore the region of corrupted d ata is in such a shape that the use of a priori information on the fin ite support of the object alone is not sufficient to recover the missi ng data. We show that with some suitable choice of scanning configurat ion and with an innovative method of data combination, all the Radon d ata can be obtained accurately. The algorithm is mathematically exact, and requires no iterations and no additional measurements. The method can be applied to inspect portions of large industrial objects in ind ustrial imaging, as well as to image portions of human bodies in medic al diagnosis.