(Left) pre-treatment CT dry slice (a) and wet slice (b) of sample S3 before registration, and the corresponding registered dry (a′) and wet (b′) slices. (Right) post-treatment CT dry slice (c) and wet slice (d) after registration, and the corresponding registered dry (c′) and wet (d′) slices. The slices were chosen at 2 mm to the front of the sample. The red and green ovals show the features used in image registration for the pre- and post-treatment images, respectively.