Three-Dimensional Registration of Cardiac Positron Emission Tomography Attenuation Scans

A method is described and tested which allows three-dimensional registration of two cardiac PET attenuation scans of the same subject acquired at different times. The alignment method is based on maximizing the correlation coefficient between the stacks of slices obtained during each of the two imaging sessions. The method appears accurate to better than 1 mm in x, y and z, and better than 1.5 o in the three angles of rotation. The method has been tested by using it to realign deliberately misaligned attenuation scans, and also by using realigned attenuation scans to correct fluorodeoxyglucose (FDG) emission scan data