CT metal artifacts simulation under x-ray total absorption

Computed tomography (CT) is a powerful tool for reconstruction and analysis of inner structure of objects applied in various fields. Although many classes of objects of interest may have highly absorbent inclusions, leading to a certain type of distortions on reconstructed volume images (metal-like artifacts). The correction of this type of artifacts can't be considered a solved task, despite all the efforts in this direction. The development and research of methods for suppressing CT artifacts require high-quality synthetic data which allow for numerical assessment of the accuracy of the metal-like artifacts reduction methods and training of neural networks. Although simplified methods considering only beam hardening and Poisson photon distribution are commonly used to simulate the data with type of distortions. In present work we design experiments using the tomographic scanner of the Federal Research Center "Crystallography and Photonics" of the Russian Academy of Sciences to demonstrate that in some cases beam hardening may not be the dominant reason for the arising of metal-like artifacts. These experiments are closely analyzed and modeled within different approaches. The problems in both simplified and state of the art approaches are emphasized and discussed. The provided results show the importance of paying attention to the dark current modeling for synthesized data generation under the conditions of total photon absorption.