Combined PET and X-ray CT tomograph

A combined positron emission tomography (PET) and X-Ray computerized tomography (CT) tomograph for acquiring PET and CT images sequentially in a single device, said combined PET and X-Ray CT tomograph comprising:

• a CT scanner having a patient gantry, said CT scanner including a plurality of detectors mounted on a rotating support, said CT scanner being provided for acquiring a CT image;
• a PET scanner having a patient gantry separate from said CT scanner patient gantry, said PET scanner including a plurality of detectors, said PET scanner being provided for acquiring a PET image;
• a patient support for supporting a patient positioned within each of said CT scanner patient gantry and said PET scanner patient gantry, said patient support being movable axially within each of said CT scanner patient gantry and said PET scanner patient gantry;
• a processor for correcting said CT image for artifacts due to field of view truncation, for reconstructing said CT image to achieve a reconstructed CT image, for generating attenuation correction factors from said reconstructed CT image, for correcting said PET image for scatter to achieve a scatter-corrected PET image, applying said attenuation correction factors to said scatter-corrected PET image to achieve an attenuation-corrected PET image, for reconstructing said attenuation-corrected PET image to achieve a reconstructed PET image, and for fusing the reconstructed CT image and the reconstructed PET image to achieve a fused PET/CT image, wherein said processor corrects said CT image for artifacts by obtaining a non-corrected PET image reconstructed without attenuation correction, by determining a boundary of a truncated portion of a selected region of the patient using said non-corrected PET image, by estimating a volume within said boundary of the truncated portion of the selected region using an average linear attenuation coefficient for the truncated portion of the selected region and by adding said volume to said CT image;
• and
• a display device for displaying at least one of the reconstructed CT image, the reconstructed PET image and the fused PET/CT image generated by said combined PET and X-Ray CT tomograph.