Beam Hardening Artifacts in CT (Single and Dual Energy)

Beam hardening artifacts in CT lead to darkening in the image such as cupping artifacts and dark streaks between highly attenuating objects such as bone or iodine.

The physics of beam hardening can be traced to the harder x-ray beams having effectively a lower x-ray attenuation, and longer path lengths create harder x-ray beams.

Water based pre-correction does a good job of correcting the cupping artifacts but dark streaks can remain between bone or iodine regions. So called higher order corrections for beam hardening help to significantly reduce the dark streaks.

Finally, dual energy CT and photo-counting CT offer a methods to inherently remove beam hardening artifacts through the acquisition where material specific information can be computed.