Precise Evaluation of Positioning Repeatability of MR-Compatible Manipulator Inside MRI

In this paper, we experimentally tested the positioning repeatability of MR-compatible manipulator with a CCD laser micrometer inside MRI. To evaluate the performance of MR-compatible manipulator inside MRI, the measuring system must be confirmed to work correctly inside MRI in advance. Therefore, the measuring system was tested to see if it can measure a specimen similarly regardless to inside or outside MRI. The results inside MRI were different from those outside MRI but the differences were small in comparison with the typical error of our manipulator. With this measuring system, the positioning repeatability of our MR-compatible manipulator was tested inside MRI with image sequence, inside MRI without image sequence, and outside MRI. The results proved that the manipulator performed 0.17[mm] translational and 0.17[deg] rotational positioning repeatability on average, whether inside or outside MRI, whether with or without image sequence.