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People working with or close to MRI scanners may have a heightened risk of an accident driving to or from work and – in the case of women – abnormal menstrual bleeding. Research carried out by the Institute for Risk Assessment Sciences (IRAS) at Utrecht ľ�ϸ���Ӱ�� (Faculty of Veterinary Medicine) among members of the Dutch Society of Medical Imaging and Radiotherapy (NVMBR) shows that exposure to stray electromagnetic fields from these scanners would not appear to be without risk.

MRI scanners are a blessing to patients. They avoid the need for exposure to the ionising radiation that plays a role in techniques such as conventional radiology and CT scans. But exposure to stray electromagnetic fields from MRI scanners appears to be putting the people who work with or close to these scanners (such as medical imaging and radiation technicians) at risk.

Dizziness

Previous research carried out by the Institute for Risk Assessment Sciences (IRAS) at Utrecht ľ�ϸ���Ӱ�� revealed that people working in this profession sometimes experience dizziness after being exposed to stray electromagnetic fields from MRI scanners. The chance of dizziness appears to increase in line with the level of exposure to these fields. The IRAS also found evidence of an increased risk of accidents among people testing MRI systems at one of the manufacturers. It then seemed logical to study the health effects on medical imaging and radiation technicians in more detail.

Accidents driving to and from work

Together with the Dutch Society of Medical Imaging and Radiotherapy (the union representing medical imaging and radiation technicians), the IRAS conducted a study of the incidence of accidents and of abnormal menstrual bleeding among members of their profession who had worked with conventional radiology, MRI or both techniques. Almost five hundred medical imaging and radiation technicians took part in the study. The researchers gathered data about accidents and near-misses driving or cycling to and from work, health, lifestyle, and job, duties and responsibilities.

The risk of medical imaging and radiation technicians who had worked with MRI during the 12 months preceding the study having an accident or a near-miss turned out to be twice as high. The risk rose in line with the frequency with which people had worked with MRI and was higher among those who had worked with more powerful MRI scanners. This effect was evident in journeys both to and from work. The mechanism behind this discovery is still unclear, but additional research should shed more light.

Abnormal menstrual bleeding

The researchers also studied data relating to almost four hundred female medical imaging and radiation technicians, half of whom had worked with MRI and approximately 20% of whom had an IUD. The chances of this group having abnormal menstrual bleeding turned out to be twice as high as that of medical imaging and radiation technicians who did not have an IUD and had not been exposed to MRI. Medical imaging and radiation technicians with an IUD who were close to scanners in operation were three-and-a half times as likely to experience abnormal bleeding.

“Both studies were based on the same observational cross-section, so it is too soon to draw firm conclusions,” says Hans Kromhout, researcher with IRAS. “We don't have any hard proof of a causal link, but the results certainly confirm conclusions from previous research studying accidents after a similar type of exposure. Cases of abnormal menstrual bleeding have also been reported in Italy.”

Follow-up research

The researchers’ conclusion is that follow-up research is needed. “MRI scanning is becoming more commonplace, the systems are increasingly powerful and more interactive applications are being developed,” says Kromhout. “Volunteers and patients could also be affected. This matter needs serious attention.”

Link to the publications:

• A. Huss, K. Schaap, H. Kromhout. Environmental Research.
• A. Huss, K. Schaap, H. Kromhout. Magnetic Resonance in Medicine. 

Contact details: Professor Hans Kromhout (h.kromhout@uu.nl) (tel. +31 6 34502449)