1. A scanning and data acquisition method for three dimensional computerized tomography (CT) imaging of an object in a field of view radially centered on a predetermined axis, the method comprising the steps of: applying cone beam energy from a cone beam source to at least a portion of the object; defining a source scanning trajectory as a path traversed by the source; using the cone beam source fixed relative to an area detector with both source and detector movably positioned relative to the object to scan about the object; specifying the source scanning trajectory as a helical path defining a plurality of mutually spaced stages on a predetermined geometric surface surrounding the field of view such that each plane passing through the field of view intersects the scanning trajectory in at least one point, the area detector having a predetermined dimension extending sufficiently along a direction generally parallel to the predetermined axis to span at least the two consecutive stages having the largest spacing therebetween, thereby obviating the predetermined dimension of the detector from fully spanning the field of view along the predetermined axis; scanning at a plurality of positions along the source scanning trajectory to obtain cone beam projection data corresponding to respective portions of the object; and using the cone beam projection data to provide a data set which can be reconstructed into an image of the object.