Abstract: A computed tomography scanner includes a housing, a conveyor disposed at least partially within the housing and configured to move an object to be scanned through the housing along a direction of travel, a gantry connected to the housing and configured to receive the object to be scanned, an x-ray source attached to the gantry and configured to provide an x-ray beam that extends along a length in the direction of travel, and detector arrays attached to the gantry and configured and disposed to receive and detect x-rays from the x-ray source, the detector arrays being displaced relative to each other in the direction of travel an array spacing distance such that a geometric efficiency of the arrays is less than about 80%.

Abstract: The threat determination process for CT scan of baggage eliminates the need for complete reconstruction the bag. The CT scan data is analyzed during scanning to locate potential threats. The analysis is based upon a lineogram representing objects in the bag. The mass, size, location and atomic number of objects are determined based upon the lineogram data. Any potential threats are further subjected to data modification and reconstruction to enhance the view of the potential threat. Dual energy scanning may also be used to determine density for resolution of potential threats.