Methods for Beam Hardening Artifacts Reduction in CT

Computed tomography is widely used for disease detection. On many occasions, image quality is affected due to the effect of hardening the X-ray beam, generating artifacts. In the present research, several methods used for the reduction of metallic artifacts (NMAR, ISMAR and LIMAR) were adapted to the reduction of artifacts by X-ray beam hardening, evaluating their effectiveness through quantitative and qualitative metrics of image quality on regions of interest (ROI). The metrics were: signal-to-noise ratio, image contrast, edge visibility, 10% of the MTF and the expert evaluation on a 8 points scale. The different methods were implemented on Matlab. To study its performance, images corrupted with this type of artifact from a physical phantom and two from patients were used. The method that showed the best performance was NMAR, but its computational efficiency for clinical routine is highly dependent on the hardware used. The methods studied do not provide satisfactory results in images that present large areas of very dense tissue.