[Risks from magnetic fields and radiowaves in equipment for magnetic resonance tomography]

The use of Nuclear Magnetic Resonance Imaging for diagnostic purposes requires a careful analysis of potential risks for workers, patients and public. Aim of this work is a review of the most important biological effects produced by static magnetic fields, radiofrequency fields and field gradients. It's common opinion in fact that the use of magnetic and radiofrequency fields instead of ionizing radiations fields is a safety warranty for patients and workers. Biological experiments in small animals and microorganisms show that also in this case some risks may be expected, due to the trend to employ as much high as possible magnetic fields (and therefore radiofrequency fields). The available data show that the normally used magnetic and radiofrequency fields are below the threshold for somatic effects but denote the necessity of a careful risks/benefit analysis for some patients groups (pacemakers and small surgical metallic implants carriers) and the need of extended and deep studies to specify a possible synergy of different physical agents and incidental oncogenic and teratogenic consequence on the patient.