Figure 1.

An illustration example on scanning procedures for 4D CT. (a) ‘Full views’ corresponds to full data acquisition with 32 projections for each phase; (b) ‘partial views’ corresponds to partial data acquisition with 8 projections, which is temporally stationary in each phase; (c) ‘dynamic views’, again with 8 projections, is, however, dynamically variant among phases, so that any view can be swept in some phase within a full dynamic cycle while avoiding redundant measurements of the common background structure at different phases. In this example one data acquisition cycle is synchronized with 4D images with four phases. Note that no temporal periodicity of the images is assumed.