Due to a lack of financial resources, we unfortunately have to suspend the import of any new radio frequency and mobile phone-related articles as of now (November 27, 2017). We apologize for this inconvenience and will keep you informed.

Because we received a large number of inquiries, we set up a bank account to accept donations. With their aid, we hope to resume, at least partly, the import of newly published articles to the RF archive of the EMF-Portal. Any contribution is greatly appreciated. Thank you for your kind support!

DONATION ACCOUNT: Uniklinik RWTH Aachen, IBAN: DE27 3905 0000 0013 0040 15, BIC: AACSDE33, Reference: GB-FM/380454/Arbm



MRI (magnetic resonance imaging) is a technique for visualizing internal structures of the body, particularly the soft tissues. In this way, pathological alterations in the body can be detected. Inside of the MRI there is a magnet generating a magnetic field that is several thousand times higher than that of the geomagnetic field.
Modern high field clinical MRI scanner
photo: KasugaHuang, license: CC BY-SA 3.0, via Wikimedia Commons
During a MRI procedure the patient is exposed a strong static magnetic field. During the MRI the magnetic characteristic of the atomic nucleus induce a certain orientation of the atoms within the magnetic field. Hereby, the atomic nuclei (e.g., hydrogen atoms) within the tissues of the body take up an identical alignment. By an electromagnetic radiofrequency pulse, this orientation is deranged. When the nuclei take back their orientation after the pulse, they emit an electromagnetic signal, which is converted to give the image.
MRI scan of a knee
photo: Test21, license: CC BY-SA 3.0, via Wikimedia Commons
In daily clinical practice, open MRIs are normally operated from 0.2 - 1 T and closed MRIs from 1.5 - 3 T for the examination of patients. Only in research facilities, magnetic fields from 7 T up to 9.4 T are used.

Typical measurement values for MRI can be found in the database of exposure sources.