An X-ray CT scanner for imaging an object is provided. The scanner includes an X-ray emitter configured to emit X-ray beams, a detector array including a plurality of detector elements, and a precollimator positioned between the X-ray emitter and the object, the precollimator configured to prevent the emitted X-ray beams from being directly incident on a first subset of the plurality of detector elements, and allow the emitted X-ray beams to be directly incident on a second subset of said plurality of detector elements. A processing device communicatively coupled to the detector array is configured to determine a signature of the object based on a first set of data acquired using the first subset of the plurality of detector elements, and tomographically reconstruct an image of the object based on a second set of data acquired using the second subset of said plurality of detector elements.
