18-03 Physiological Hazards
The physiological risks of magnetic and radiofrequency fields have been intensively examined for a long time; still, there were hardly any long-term studies following persons who were exposed to such fields.
Known or feared negative health effects. Already in 1988 there was a report about sensations of vertigo, nausea, and metallic taste in a group of volunteers. More than twenty years later, scientific publications from the Netherlands throw new light on hazards of ultra-high field magnetic resonance equipment operating at fields higher than 2 Tesla. Rats avoid magnetic fields higher than 2 T.
There is also a danger of radiofrequency heating, shear forces between brain tissues, nerve stimulation by gradient fields, as well as genotoxic effects.
Numerous open questions concerning the safety of MR imaging remain, mostly at fields beyond 2 Tesla. However, to date there is no proof of any lasting harmful effect of MR equipment for humans below 2 Tesla.
To get an impression of the complexity of the topic we shall discuss some possible physiological hazards in more detail on the following pages.