Computed tomographic beam-hardening artefacts: mathematical characterization and analysis.
This paper presents a mathematical characterization and analysis of beam-hardening artefacts in X-ray computed tomography (CT). In the field of dental and medical radiography, metal artefact reduction in CT is becoming increasingly important as artificial prostheses and metallic implants become more widespread in ageing populations. Metal artefacts are mainly caused by the beam-hardening of polychromatic X-ray photon beams, which causes mismatch between the actual sinogram data and the data model being the Radon transform of the unknown attenuation distribution in the CT reconstruction algorithm. We investigate the beam-hardening factor through a mathematical analysis of the discrepancy between the data and the Radon transform of the attenuation distribution at a fixed energy level. Separation of cupping artefacts from beam-hardening artefacts allows causes and effects of streaking artefacts to be analysed. Various computer simulations and experiments are performed to support our mathematical analysis.
Department of Computational Science and Engineering, Yonsei University, Seoul, Republic of Korea.
Hyoung Suk
HS
Park
Department of Radiology, Yonsei University College of Medicine, Seoul, Republic of Korea.
Yong Eun
YE
Chung
Department of Computational Science and Engineering, Yonsei University, Seoul, Republic of Korea seoj@yonsei.ac.kr.
Jin Keun
JK
Seo
Radon transform; beam-hardening artefacts; computerized tomography; wavefront set