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Abstract #1848

SAR Reduction using Non-Linear Gradients

Emre Kopanoglu1,2, Burak Akin1, Vakur B. Erturk2, Ergin Atalar1,2

1National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; 2Department of Electrical & Electronics Engineering, Bilkent University, Ankara, Turkey

Slice-profile is related to the frequency-spectrum of an RF envelope through the gradient field, which is conventionally linear. Although a rectangular pulse is more efficient as far as SAR is concerned, apodized sinc envelopes are widely used for excitation because the slice-profile of a rectangular pulse is not desirable. In this study, a method that employs non-linear gradients to modify the slice-profile of a rectangular pulse into a feasible one is proposed. As a sample study, the method is compared to an apodized sinc envelope, and showed 41% reduction in SAR as well as an increase in correct excitation in the region of interest from 71% to 94%.