Figure 5. Evaluation of deformable registration as applied to response assessment. The CT component of pre‐ and post‐treatment PET scans is used for the registration and the resulting transform is applied on the SUV values for response assessment. Although algorithm 1, depicted in the left column, provides the best match voxel‐wise, clinically, algorithm 3 is more suitable to describe anatomical changes. Pre‐ and post datasets are shown in (a) and (b), while each column in the results section illustrates a different deformable registration algorithm.