Automated, reference-free local error assessment of multimodal deformable image registration for radiotherapy in the head and neck

Background Head and neck MR-CT deformable image registration (DIR) for radiotherapy planning is hindered by the lack of both ground-truth and per-patient accuracy assessment methods. This study assesses novel post-registration reference-free error assessment algorithms, based on local rigid re-registration of native and pseudomodality images. Methods Head and neck MR obtained in and out of the treatment position underwent DIR to planning CT....