Analysis Of Scatter Artifacts In Cone-Beam Ct Due To Scattered Radiation Of Metallic Objects

Cone-beam computed tomography (CBCT) is a widely used technique for diagnostic or monitoring purposes. Compared to the traditional CT, a CBCT is more affected by scatter artifacts because of the large volume being irradiated by the beam. The research divulged in this paper is about the assessment of the influence that metallic implants may have on degrading image quality of CBCT due to scattered radiation. The evaluation method is based on Monte-Carlo (MC) simulations of the physical processes that X-ray photons undergo in typical CBCT setups, in presence and absence of highly scattering metallic implants (coils used for treatment of aneurysms and pacemakers). The results show that the scattered radiation caused by metallic objects and reaching the detector produces slight degradation of CBCT image quality and, moreover, it is demonstrated that the intrinsic absorption and beam-hardening effect of these implants have bigger impact on the overall image fidelity.