Analysis of the MRI-Used Bird Cage Resonator

Abstract

An application of Magnetic Resonance Imaging (MRI) has become a part of the every-day medical diagnostics resulted in an interest in related possible human health effects. An appropriate way of a calculation of a RF electromagnetic energy deposition in the human body is performing a numerical simulation. These calculations have been performed for the case of the modeled head exposed to the RF field of the saddle-shaped coils¹. The comparison and the advantages of using circular over linear polarization² led to the application of a bird-cage coil³. The analysis performed here gives the resonant frequency calculation, followed by a calculation of a current distribution in the rods. This is of importance, because these currents give rise to the transverse RF magnetic field, which is necessary for nuclear magnetic resonance imaging. Therefore, the knowledge of the current distribution in rods represents a basis for performing numerical simulations later on.