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.