Читать книгу Essentials of MRI Safety - Donald W. McRobbie - Страница 26

Other configurations of MRI systems are also available, although less common. Resistive magnets producing fields up to 0.4 T are sometimes configured as open or C‐arm systems, affording better access to the patient and a less claustrophobic experience. Resistive magnets have one safety‐related advantage: the field can be routinely switched off.

Permanent magnets are used in low field niche scanners for extremity imaging or in “upright systems”. These employ various rare earth materials such as neodymium‐iron‐boron (Nd‐Fe‐B). Their magnetic field is always present.