Fig. 1From: Target volume delineation of anal cancer based on magnetic resonance imaging or positron emission tomographyDelineations in one patient; all images from the same slice. Top row shows PET-based delineations. The left image is a single observer delineation of GTV (red) and GTVT (green) in the PET/CT basis. The central image compares the three observers’ GTVs with each other, and the right compares the GTVTs. These two latter panels show delineations in the planning CT basis. The bottom row shows three corresponding MRI-based delineationsBack to article page