A practical method to reducing metal artifact for dental CT scanners

An integrated and effective metal artifact reduction method named Metal Erasing (ME) especially suited to dental applications is proposed. Layout of metals is identified as metal-only tomogram, using its characteristics of X-ray opacity and simple image processing technique of binarization together with backward projection. Metal-only sinogram is calculated by forward projection of the metal-only tomogram, and identifies corrupted areas on the original sinogram. The areas are then replaced by interpolation, and filtered back projection (FBP) produces a tomogram without figures of metals. The metals can be reproduced by overlaying already obtained metal-only tomogram utilizing linear characteristics of FBP. It is expected that the ME method can be incorporated into commercial CT scanners easily with reasonable computational overhead.