Direct backprojection-filtration formula for region-of-interest imaging with few additional projections

International audienceThis paper provides a backprojection-filtrationmethod for image reconstruction in divergent circular fan-beamand cone-beam geometries with flat detectors. It is based on asplitting of the acquisition angular range into angular sectorsadmitting filtering orientations in the image space where asimple, mono-directional Fourier-based filtering is possible. Thenew workflow is used for region-of-interest (ROI) reconstructionfrom dual-rotation acquisitions, consisting of a truncated, denselysampled acquisition and of a few additional non-truncated views.Results show that the reconstructed images using our newapproach are similar to what FBP would achieve in the non-truncated case, and demonstrate the feasibility of an accuratedirect reconstruction method for dual-rotation ROI imaging withvery few non-truncated views.