Method and apparatus for reducing artifacts in computed tomography image reconstruction

A computed tomography apparatus, comprising:

• a scanner for scanning an object using X-rays to obtain original data for generating an original reconstructed image;
• and
• a processor operably coupled to said scanner and programmable to obtain an original reconstructed image and an original sinogram, and programmable to determine a proportion of metal pixels in the original reconstructed image,
• wherein, if the proportion of metal pixels is greater than a first threshold value, the processor is configured to:
• generate an expanded metal template based on the original reconstructed image, wherein the expanded metal template includes a two-dimensional or three-dimensional expansion for different pixels,
• generate a metal-free, MAR image based on the expanded metal template and the original sinogram, and
• generate a final image based on the expanded metal template and the metal-free, MAR image;
• and
• wherein, if the proportion of metal pixels is less than a second threshold value, the processor is configured to:
• generate an expanded metal template based on the original reconstructed image,
• generate a metal-free, MAR image based on a treatment including weighting of the expanded metal template and the original sinogram, and
• generate a final image based on the expanded metal template and the metal-free, MAR image.