This document provides an overview of the operation of a computed tomography (CT) system and the interpretation of the results with the aim of providing the operator with technical information to enable the selection of suitable parameters. This document applies to industrial imaging (i.e. non-medical applications) and provides a consistent set of definitions of CT performance parameters, including how these performance parameters relate to CT system specifications. This document deals with computed axial tomography and excludes other types of tomography such as translational tomography and tomosynthesis.