Figure 6.

Comparison of conventional Demons and XDD registration in a deformable phantom containing real deformations and a ∼1 cm³ excision of material emulating a tissue-in-air excision scenario. Coronal slices from the CBCT volume are shown. (a) Registered image (and zoomed-in region) resulting from the conventional Demons approach, with (b) NCC map (across the zoomed-in region) computed using a 10 × 10 × 10 voxel sliding window across the region of interest. (c) and (d) The same, for the XDD registration approach. Whereas (a) and (b) exhibit unrealistic distortion and reduction in NCC, (c) and (d) demonstrate a fairly accurate ejection of voxels within the region of excision and maintenance of NCC (with reduction within the air void likely due to quantum noise).