A method for correcting a positron emission tomography (PET) emission
image is described. The method includes obtaining a PET emission sinogram
of an object, obtaining a computed tomography (CT) image for a scanned
portion of the object, the object having a truncated portion outside a
field of view (FOV) of a CT image, determining a correction set of CT
data based on a measured set of CT data within the CT sinogram,
generating modified attenuation correction factors from the measured and
correction sets of CT data, and correcting the PET sinogram using the
modified attenuation correction factors.