بررسی میزان مواجهه شغلی با میدان های مغناطیسی پایا واثرات بهداشتی آن در مراکز تصویر برداری تشدید مغناطیسی

 Background and aim:  Magnetic resonance imaging as one of the best medical scanning technique is considered to be the most important sources of static magnetic fields. The staffs of MRI ´s units frequently exposed to these static magnetic fields. This study aims to determine the occupational exposure level to mentioned field and its related health effects in MRI´s units.    Methods:  The occupational exposure level of 20 staffs in the four MRI ´s units in the Shiraz city was measured using personal monitoring instrument model HI 3550 based on IEEE C95.3.1 method. A questionnaire related to health effects of magnetic fields was distributed and completed between 25 staffs of MRI ´s units and 30 nurses employed in typical hospital as a control group. Finally, the obtained data was analyzed by spss19 software.    Results:  The result showed that the time weighted average of the staffs exposure was 48.6±2 mT/8 hours in relation to 1.5 T MRI systems. Therefore, occupational exposure of staffs was lower than Iran national exposure limits (60mT/8 hours). In addition, magnetic field strength decreased with increasing the distance from MRI system. In addition, the frequency of health effects related to magnetic fields such as anxiety, sleep and concentration disorders and tiredness between case and control groups were not significant (P >0.05).  Conclusion: The staffs exposure to static magnetic fields compared with the national exposure limits were in the acceptable level. However, MRI devices were assigned to be the most important sources of static magnetic fields. While the available evidences in the scientific literatures in the worldwide are not sufficient to draw any conclusions about potential health effects of magnetic field, it is suggested that, health and training programs were applied to increase the awareness of staffs