M.A. ALI

Dept. of Biophysics, Faculty of Science, Cairo University, Giza – Egypt, P.O. Box 12613

Abstract. The safety aspects of the magnetic resonance imaging (MRI) requires an understanding of the interactions between the electric and magnetic fields generated by such instruments and the human body. Knowledge of MRI safety can not only guide radiofrequency coil and pulse sequence design but can also affect sequence selections, thereby ensuring safe and efficient system operation. However, in addition to the static magnetic field, power intense sequences, fast gradient switching, and localized imaging / spectroscopy all have the potential of subjecting the human body to intense magnetic and electric field fluctuations. This further accentuates the need for a detailed understanding of the effects of exposure to these fields. Such an effect was evaluated for 25 patients subjected to MRI through measurements of some biophysical properties of erythrocytes. Results showed that there is a significant decrease (p < 0.05) in RBC membrane permeability, cellular membrane elasticity and erythrocytes sedimentation rate (ESR) during MRI, but post MRI there are non significant changes (p > 0.05). Scanning electron microscope (SEM) was used to follow the morphological modification of erythrocytes during MRI. It is concluded that a relatively large force (high magnet and RF) causes the membrane to undergo a continuous deformation. Removal of the force results in the cessation of deformation of the RBC membrane (reversible changes). These results confirm the safety of MRI.

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