Effects of Phase Constitution of Zr-based Alloys on Their Magnetic Susceptibility to Prevent Artifacts in MRI

摘要

Magnetic resonance imaging (MRI) is used as an important diagnostic tool for whole-body, especially for brain. This method has advantages in non-invasion and no exposure to radiation for the human body. However, images of organs and tissue are disturbed around metallic implants and artifacts occur in intense magnetic field of MRI instruments [1]. On the other hand, over 70% of implant devices consist of metals because of their high strength, high toughness and good durability, while magnetic susceptibility of metals is still relatively large. Therefore, metals show a low magnetic susceptibility or antimagnetic materials are required for medical devices and instruments for operations and treatments used under open MRI. Among various pure metals, Zr possesses low magnetic susceptibility compared to Ti, Co and Fe alloys. In addition, it is reported that Zr-Nb and Z-Mo alloys show good mechanical properties [2], corrosion resistance and constituent elements show low toxicity [3]. Thus, the Zr-based alloys are the promising alloy systems for preventing artifacts under MRI. The purpose of this study is to investigate the relation between magnetic susceptibility and composition of Zr-Nb and Zr-Mo alloys. Effects of phase constitution on their magnetic susceptibility of the Zr-based alloys were investigated. These researches will enhance the development of Zr-based alloys that prevent artifact under MRI.