Development of a 1.0 T MR microscope using a Nd-Fe-B permanent magnet

A compact 1.0 T MR microscope was developed using a permanent magnet made of high performance Nd-Fe-B magnetic material and a compact MRI console (54 cm (W) × 77 cm (H) × 60 cm (D), 80 kg weight). Since the magnetic field of the permanent magnet had a large temperature coefficient (−1200 ppm/deg), an internal NMR locking technique was developed for the imaging sequences. The performance of the system was evaluated using several biological specimens. As a result, good SNR 3D images at (50 μm)3–(200 μm)3 voxel dimensions were obtained in practical imaging times (0.5–7.5 hours). Thus we have concluded that the permanent-magnet compact MR microscope has great promise as a research or analytical tool.