Figure 8.

(a) Deformed pCT (light) and directly outlined rCT (dark) structure comparison for a single patient—the right lung (green), spinal canal  +  5 mm (blue), heart (purple) and CTV  +  1 cm (red) are overlaid for both structure sets on a single transverse slice. Whilst the lung and spinal canal are similar, the CTV  +  1 cm outlined on the rCT is much larger than the deformed CTV  +  1 cm. Although the heart appears well-matched on this slice, the heart that was outlined on the rCT extends further superiorly than the deformed structure. (b) Directly outlined spinal canal  +  5 mm (top) compared with deformed spinal canal  +  5 mm (bottom). Although the structures are similar, there is a noticeable difference in maximum dose as the directly outlined rCT structure slightly overlaps the treatment field whereas the deformed structure does not.