LOCAL CT IMAGE RECONSTRUCTION WITH LIMITED X-RAY EXPOSURE

Methods and apparatus for reconstructing an image of an object utilizing an imaging system, in which a limited width beam of radiation is emitted towards the object, the limited width beam of radiation having a fan beam angle extent selected to encompass a perimeter of a region of interest (ROI) within the object and to encompass less than a perimeter of the object itself; a set of truncated projection data of the object, including projection data of the ROI, is obtained by detecting the radiation from the limited width beam of radiation passing through the object; low frequency components of the set of truncated projection data are estimated; and an image of the ROI within the object is reconstructed utilizing the set of truncated projection data and the estimated low frequency components. Information from a limited set of complete projection data can be used to estimate the low frequency components of the set of truncated projection data, but such information is not required.