Feasibility of sharpening limited-angle tomography by including an orthogonal set of projections

Abstract

In single photon emission nuclear medicine, computed tomography systems that employ only a limited angular range of projection data suffer from blurring in the depth (or z) direction. With simulated data, we show that including a second set of projections taken in an orthogonal direction sharpens the image in the z direction. For heart applications, this sharpening improves the sizing of a simulated 2 cm diameter "hot" infarct by 39%. It also should improve the contrast of "cold" infarcts by eliminating blurring from other planes, but here we have found a complication, in that, with the present approximate algorithm, effects from the lack of symmetry in two-view tomography may overshadow benefits from contrast improvement. Further simulation study is called for.