Deformable Image Registration - Improved Fast Free Form Deformation

In this paper, we describe a class of deformable registration techniques with application to radiotherapy of prostate cancer. To solve registration problem we introduced Jacobi and successive over-relaxation methods and compared them with the Gauss-Seidel used in the variational framework previously proposed in literature. A multi-resolution scheme was used to improve speed of computation, robustness and ability to recover bigger image deformations. To investigate the properties of these algorithms they were tested using simulated data with known displacement filed and real CT images . The results show that it is possible to improve currently widely used algorithms by introducing simple modifications in the numerical solving scheme.