Nonrigid Versus Rigid Registration of Thoracic ¹⁸F-FDG PET and CT in Patients with Lung Cancer: An Intraindividual Comparison of Different Breathing Maneuvers

Abstract

The alignment quality of thoracic (18)F-FDG PET/CT exhibits a marked dependence on the breathing maneuver performed during the CT acquisition, as demonstrated in an intraindividual comparison. Nonrigid registration is a significant improvement over rigid registration if the CT is performed during full inspiration or full expiration. The best fusion results are obtained with the CT performed at mid breath-hold using rigid registration, without an improvement using nonrigid algorithms.