title: Analysis of iterative region-of-interest image reconstruction for x-ray computed tomography.
abstract: One of the challenges for iterative image reconstruction (IIR) is that such algorithms solve an imaging model implicitly, requiring a complete representation of the scanned subject within the viewing domain of the scanner. This requirement can place a prohibitively high computational burden for IIR applied to x-ray computed tomography (CT), especially when high-resolution tomographic volumes are required. In this work, we aim to develop an IIR algorithm for direct region-of-interest (ROI) image reconstruction. The proposed class of IIR algorithms is based on an optimization problem that incorporates a data fidelity term, which compares a derivative of the estimated data with the available projection data. In order to characterize this optimization problem, we apply it to computer-simulated two-dimensional fan-beam CT data, using both ideal noiseless data and realistic data containing a level of noise comparable to that of the breast CT application. The proposed method is demonstrated for both complete field-of-view and ROI imaging. To demonstrate the potential utility of the proposed ROI imaging method, it is applied to actual CT scanner data.
authors: University of Chicago, Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States.
authors: Emil Y
authors: EY
authors: Sidky
authors: University of Chicago, Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States.
authors: David N
authors: DN
authors: Kraemer
authors: University of Chicago, Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States.
authors: Erin G
authors: EG
authors: Roth
authors: XCounter AB, Svärdvägen 23, floor 1, SE-182 33 Danderyd, Sweden.
authors: Christer
authors: C
authors: Ullberg
authors: University of Chicago, Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States.
authors: Ingrid S
authors: IS
authors: Reiser
authors: University of Chicago, Department of Radiology, 5841 South Maryland Avenue, Chicago, Illinois 60637, United States.
authors: Xiaochuan
authors: X
authors: Pan
keywords: iterative image reconstruction; region-of-interest imaging; x-ray CT