Table 1.

Summary of the validation protocol procedure, including the analysis performed and images evaluated for each of the protocol's four components.

	Analysis	Images Registered
Phantom study	Qualitative visual analysis of registration	CT to CT; MRI to MRI; PET to PET; MRI to CT; PET to CT
Relative validation	Comparison of post‐registration similarity measures	PET/CT; Longitudinal PET; Longitudinal thoracic CT; Male pelvic MRI to planning CT; Male pelvic MVCT to planning CT
Intra‐modality	Evaluation of post‐registration axial and 3D displacement errors (DE)	Synthetic thoracic CT to original thoracic CT
Inter‐modality	Evaluation of post‐registration contour metrics	Male pelvic MRI to planning CT