1. A method of detecting objects in computed tomography (CT) data for a region comprising: performing a first object detection process on the CT data for the region to detect a first type of object associated with the first object detection process; and performing a second object detection process on the CT data for the region to detect a second type of object, said second object detection process being associated with the second type of object, wherein performing the second object detection process on the CT data for the region comprises processing the CT data for the region to eliminate data that represents objects of the first type of object from the CT data for the region.