1. A method of pre-processing cone beam projection data for reconstructing substantially free of interpolation induced artifacts a three-dimensional (3D) image of a portion of an object using an inverse Radon transformation, said method comprising the steps of: providing a mutually spaced cone beam irradiating source and a surface array radiation detector in fixed relationship to one another; providing an object between said source and said detector; irradiating at least said portion of said object within a field of view of said source; moving both said source and detector relative to said object for scanning around said portion along a scan trajectory enclosing upper and lower extents of said portion by respective upper and lower scan paths joined therebetween by a predetermined connecting path; identifying a first region on said surface array detector as a cone beam projection of said object bounded between respective similar projections of said upper and lower scan paths; identifying second and third regions on said surface array detector respectively situated about said upper and lower scan path projections, each of said second and third regions respectively extending sufficiently beyond said first region to provide a predetermined additional cone beam projection of said object; detecting cone beam projection data at said surface array detector for a plurality of scan positions along said scan trajectory; retaining cone beam projection data acquired within said first, second and third regions; and processing said retained data to reconstruct substantially free of interpolation induced artifacts a 3D image of said portion by said inverse Radon transformation.