Department of Computational Science and Engineering, Yonsei University, Seoul, 03722, Korea.
Department of Radiology, Yonsei University College of Medicine, 03722, Korea.
Med Phys. 2017 Sep;44(9):e147-e152. doi: 10.1002/mp.12218.
This study aims to propose a physics-based method of reducing beam-hardening artifacts induced by high-attenuation materials such as metal stents or other metallic implants.
The proposed approach consists of deriving a sinogram inconsistency formula representing the energy dependence of the attenuation coefficient of high-attenuation materials. This inconsistency formula more accurately represents the inconsistencies of the sinogram than that of a previously reported formula (called the MAC-BC method). This is achieved by considering the properties of the high-attenuation materials, which include the materials' shapes and locations and their effects on the incident X-ray spectrum, including their attenuation coefficients.
Numerical simulation and phantom experiment demonstrate that the modeling error of MAC-BC method are nearly completely removed by means of the proposed method.
The proposed method reduces beam-hardening artifacts arising from high-attenuation materials by relaxing the assumptions of the MAC-BC method. In doing so, it outperforms the original MAC-BC method. Further research is required to address other potential sources of metal artifacts, such as photon starvation, scattering, and noise.
本研究旨在提出一种基于物理的方法，以减少由高衰减材料（如金属支架或其他金属植入物）引起的射束硬化伪影。
所提出的方法包括推导出一个能表示高衰减材料衰减系数能量依赖性的正弦图不一致公式。与之前报道的公式（称为 MAC-BC 方法）相比，该不一致公式更准确地表示了正弦图的不一致性。这是通过考虑高衰减材料的特性来实现的，这些特性包括材料的形状和位置及其对入射 X 射线谱的影响，包括它们的衰减系数。
数值模拟和体模实验表明，所提出的方法几乎完全消除了 MAC-BC 方法的建模误差。
所提出的方法通过放宽 MAC-BC 方法的假设，减少了来自高衰减材料的射束硬化伪影。在这方面，它优于原始的 MAC-BC 方法。需要进一步研究解决其他潜在的金属伪影来源，如光子饥饿、散射和噪声。
