A stereotactic device for use with an imager such as a magnetic resonance imager is disclosed, which permits an imaging scan to be taken with reference to a personal coordinate system (or PCS) that is independent of a machine coordinate system (or MCS). Methods using the device to obtain imaging scans are described such that the imaging scans are superimposable even if taken at different time periods using the same or a different imager. The device comprises a frame that can be reproducibly positioned on a subject and which is equipped with non-invasive affixing means and localizing means that provide the PCS. The device and methods of the invention are particularly well suited for routine initial or follow-up examinations, pre-surgical planning and post-surgical evaluation. Markers on a stereotactic device can be tracked during an MRI scan to compensate for patient motion during the scan.