Three-dimensional registration of PET and CT images

The authors describe an evaluation of the registration of positron emission tomography (PET) scans with X-ray computed tomography (CT) scans of the human. The registration is performed in three dimensions rather than slice by slice. PET and CT scan pairs are obtained for two subjects with fiducial markers placed on each subject´s head. The CT and PET scans are then registered, first by using the fiducial markers, and next by applying the registration method currently under study, completely ignoring fiducial markers. In both cases, the positions of markers in PET scans and CT scans are compared. The results based on aligning two sets of scans are presented and are considered promising.