Fig. 2.
Flowchart of the robust pulse design process. A first pulse is designed while constraining SAR to the FDA limit (Step 1). The worst case SAR (SARWC) for every SAR (and the global SAR matrix) is then calculated for maximum RF amplitude and phase chain errors (Step 2). If SARWC exceeds the SAR limit, a new pulse is designed with a reduced SAR constraint (Step 3). This process is iterated until we obtain an RF pulse with a worst-case SAR (global and local) below the safety limit. This guarantees that the SAR is never exceeded, even in the presence of error in the transmitted RF waveform.