Bio-applicable Ti-based composites with reduced image distortion under high magnetic field

When viewed using a magnetic resonance imaging (MRI) system, invasive materials inside the human body, in many cases, severely distort the MR image of human tissues. The degree of the MR image distortion increases in proportion not only to the difference in the susceptibility between the invasive material and the human tissue, but also to the intensity of the magnetic field induced by the MRI system. In this study, by blending paramagnetic Ti particles with diamagnetic graphite, we synthesized Ti _100-xC _x composites that can reduce the artifact in the MR image under the high-strength magnetic field. Of the developed composites, Ti ₇₀C ₃₀ showed the magnetic susceptibility of χ = 67.6 × 10 ^-6, which corresponds to 30% of those of commercially available Ti alloys, the lowest reported in the literature. The level of the MR image distortion in the vicinity of the Ti ₇₀C ₃₀ composite insert was nearly negligible even under the high magnetic field of 4.7 T. In this paper, we reported on a methodology of designing new structural materials for bio-applications, their synthesis, experimental confirmation and measurement of MR images.