Figure 4

Scenario of our proposed registration framework. In the first step (left) for each animal ‘R’, we registered segmented CT volumes (CT ^R,S) from different time points (t _n ) to a baseline scan and stored the deformation fields $\left(d_{t_n\to \text{base}}\right)$. Since the PET images are co-registered with these CT scans, we applied the corresponding deformation field to the segmented PET scan (PET ^R,S) in order to align the PET radiotracer regions over time (PET ^{R, aligned})(right). This process allowed visualization of changes in active PET lesions throughout the imaging study.