  Metallic implants introduce severe artifacts in CT images, which degrades the
image quality. It is an effective method to reduce metal artifacts by replacing
the metal affected projection with the forward projection of a prior image. How
to find a good prior image is the key of this class methods, and numerous
algorithms have been proposed to address this issue recently. In this work, by
using image mutual correlation, pixels in the original reconstructed image or
linear interpolation corrected image, which are less affected by artifacts, are
selected to build a combined image. Thereafter, a better prior image is
generated from the combined image by using tissue classification. The results
of three patients' CT images show that the proposed method can reduce metal
artifacts remarkably.
