Magnetic resonance safety bioeffects of gradient magnetic fields

From the safety point of view, there are areas to consider in operating a Magnetic Resonance (MR) facility. Time-varying magnetic fields, caused by the switched gradient on imaging systems, will induce currents in conductive pathways in the body. There are different thresholds for eliciting excitation for different tissues. Information was obtained from a MR research facility which could be bear in mind when a small sample is investigated although there are limitations upon the use of this information for biological tissues. Because a number of effects in man occur, there are recommendations made by the National Radiological Protection Board (NRPB) in the UK and the US Food and Drug Administration (FDA) has issued safety guidelines as well, which are considered in this work. (author)