The AAPM/RSNA physics tutorial for residents - MR imaging safety considerations

Experience and research over the past decade have demonstrated that diagnos tic magnetic resonance (MR) imaging is a biologically safe imaging modality . Specifically, there is currently no convincing evidence that there is any longterm or irreversible biologic effects associated with the radiation an d magnetic fields used in MR imaging, specifically radio-frequency (RF) rad iation, static magnetic fields, and time-varying gradient fields. However, numerous hazards of MR imaging do exist that can cause severe injuries or e ven death. These hazards are primarily the result of (a) strong magnetic fi elds and the strong force that they exert on ferromagnetic objects brought into their influence, including interference with electronic devices such a s pacemakers and other implanted electronic devices, and (b) RF bums result ing from inadvertently induced currents in conductive loops placed on the p atient's skin surface (eg, electrocardiographic leads and other monitoring devices). Other potential concerns are peripheral nerve stimulation resulti ng from rapidly switched gradients and auditory noise levels. Establishing a complete and coordinated educational program for all MR imaging facility personnel and conducting effective screening and preparation of patients sc heduled for MR imaging procedures are essential to avoid accidents and RF b ums and to maintain a safe MR imaging facility.