Enhancing the Accuracy of MRI-Compatible Robots with an Optical Tracking System

Abstract

Magnetic resonance imaging (MRI) is currently a widely used technology for obtaining a three-dimensional image of a patient’s internal structures. This study examines the measurement properties of an optical tracking system utilised in the MRI room. The results were used to assess the suitability of the device to be used as a part of the control system of a surgical robot. The position and orientation of the instrument, MRI scanner and the patient are measured using an optical tracking system in the MRI room. The measurement data can be used to display the instrument used as a part of the image of the patient. The optical tracking system used in the MRI room can also be considered as a part of the control system of a robot located in the room. When considering such use, the operations of the measuring device in different measurement conditions must be known. In terms of robot control, it is important to know the deviation attributed to measurement when defining the translation vector and orientation between two trackers. Five measurement series were carried out using the measurement device to examine the deviation in the translation vector and orientation data between two trackers. The distance and position between the trackers were changed between the measurement series. During the measurement series, the measurement device was moved to different distances from the trackers and the translation vector and orientation between the trackers were defined on the basis of the measurement results obtained. The measurements showed that the deviation of the translation vector did not significantly change as the measurement distance increased, but the deviation of orientation data between different trackers increased significantly. Deviation in the translation vector increased as the distance between trackers increased, but deviation in orientation did not change significantly.