Figure 6. Use of a volumetric data set. Projection data are typically used to reconstruct axial images of interpretive thickness for conventional review, which is performed by using printed film or with a picture archiving and communication system. Although it is occasionally useful to view thin axial images for osseous detail, axial viewing is usually performed with a section thickness of 3–5 mm. If necessary, a thin-section data set can be generated in addition to or in place of the traditional interpretive axial images. This may be called the volumetric data set because it is intended to be used not for primary axial interpretation but rather for generating high-quality multiplanar reformatted or volume-rendered images. This data set typically consists of axial images with a section thickness approaching 1 mm or even less, preferably with an overlapping interval.