Health complaints among nurses working near MRI scanners—A descriptive pilot study

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Abstract

A questionnaire-based descriptive pilot study was conducted among all nurses routinely working with MRI in the Northern part of Sweden to provide an indication of the self-reported prevalence of health complaints related to working with MRI systems.

Fifty-nine nurses (88% response rate), with on average 8 (±6) years experience with MRI scanning procedures, returned the questionnaire. In total, 9 nurses (15%) reported regularly experiencing at least one of the health complaints (1–5% for specific health complaints) attributed to arise or be aggravated by their presence in the MRI scanning room. Stratification of the results indicated that reporting of adverse symptoms was not related to the level of occupational workload/stress. However, reporting of health complaints was related to the strength of the magnet(s) the nurses worked with, with 57% of symptoms reported by those nurses working with the strongest systems (both 1.5 and 3 T scanners in this population).

Although this descriptive study did not include a control population and was based on self-reporting of health complaints, these data indicate that the prevalence of reported health complaints is not related to perceived work load or occupational stress, but does confirm data from other occupational sectors and indicates that the prevalence of adverse health complaints increases with the strength of the MRI system for nurses as well.

Introduction

Radiology nurses working with MRI (magnetic resonance imaging) (MRI Nurses) are highly exposed to static magnetic fields near the MRI scanner. Today it is most common to have clinical MRI scanners of 1.5 or 3 T, but others exist as well (up to 7 T). Personnel operating MRI scanners can, in addition to other electromagnetic fields, be exposed to high levels of static magnetic fields (SMF) surrounding the MRI scanner (magnetic stray field) and symptoms like headaches, vertigo, nausea, a metal taste, and illusions of movement are sometimes reported, especially when moving fast around the magnet bore [1], [2]. There is hardly any data available in the public domain, but what is available suggests that if symptoms are reported, these are acute and generally disappear quickly after the subject left the magnetic stray field [1], [2], and at least some seem to have an established threshold level [3]. However, the only available data in occupational situations has been collected among MR engineers and these suggest that the frequency of the reported symptoms are related to the strength of the MRI system, the duration of presence in the stray field, and the speed at which a subject moves in the field [2]. Data from controlled trials suggest that movement in heterogeneous stray fields from MRI systems affects the visual perception and visuo-motor neurobehavioral domains, most likely through interference with the vestibulo-ocular reflex [4], [5], and that the magnitude of the effects depends on the strength of the magnetic field combined with the movement speed [2], [5], [6]. It has further been argued that these effects are caused by movement in the spatial stray field itself, rather than by time-varying magnetic fields only [7] or by the gradient switching process in MRI procedures [8].

In view of the discussion about the implementation of the European Union Directive on occupational EMF exposure [9], [10], and discussions of specially controlled environments where higher limit values for static magnetic fields could be applied, it is of interest to get further information about possible health complaints among personnel working close to the MRI magnet bore; especially since an EU commissioned study and a UK HSE commissioned study both showed that the original proposed limits would be exceeded regularly by people working close to the end of the magnet bore [11], [12]. This was also showed by means of personal exposure measurements specifically for MR engineers [13].

In this descriptive pilot study a questionnaire has been distributed to all nurses routinely working with MRI in the Northern part of Sweden to obtain an overview of the degree of symptoms and when these health complaints normally occur. The aim of the pilot study was to provide an indication of the prevalence of MRI related health complaints among nurses routinely working with MRI systems.

Section snippets

Materials and methods

A questionnaire to all (N = 67) nurses routinely working with MRI systems, but who might on occasion also be involved in X-ray imaging, in any of nine hospitals in the Northern part of Sweden, has been sent out for an in depth study of their working environment and health complaints. At each hospital a contact person handed out and later collected the questionnaire.

The questionnaire concentrated on MRI related questions such as how frequently and for how long have they been present inside the MRI

Results

In total 59 (out of 67) questionnaires were returned resulting in an 88% response rate. Out of those, 10 were returned by men and 49 by women. The mean age of the population was 47 years (standard deviation (SD): ±10 years) with on average 8 (±6) years experience with MRI scanning procedures. They were involved in on average 10 (±5) MRI procedures per day (range: 1–40) which resulted in an average of 61 (±36) min in the MRI examination room (range: 2–200 min).

The prevalence of symptoms, as well

Discussion

This pilot study aimed at examining the prevalence of self-reported symptoms that have been linked to exposure to the magnetic fields from MRI systems in nurses in the north of Sweden routinely working with MRI systems.

The most important disadvantage of this exploratory study is that the questionnaire was not distributed among a comparable comparison group to provide the ‘natural occupational background’ for these symptoms in the nursing population in the north of Sweden. As such, this study

Conclusions

These data indicate that about 15% of nurses routinely working with MRI regularly experience one or more adverse health complaints which are caused or aggravated by MRI. Reporting of these symptoms is not related to occupational stress but seems related to the strength of the MRI system. This study provides a basis for a larger study where more hospitals which should include a proper control group, preferably on an international basis.

Conflict of interest

None declared.

Acknowledgements

The authors wish to express gratitude to Asst. Prof. Kjell Hansson Mild for valuable comments and discussions throughout the project. Also all nurses within the study deserve appreciations. The study was funded by the Northern County Councils.

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