A 32-Channel Parallel Exciter/Amplifier Transmit System for 7T Imaging

Introduction: Parallel transmission (Tx) generalizes conventional Tx and RF shimming, offering extra degrees of freedom and significant opportunities for optimizing Tx performance, improving pulse design trade-off, and leveraging new coil concepts. The present work of developing a 32 Tx-channel system reflects an interest in 1) exploring the opportunities thoroughly and acquiring insights to the question of “what is the optimal number of channels?” and 2) developing state-of-the-art RF sequencer and power amplifier instrumentation. There were significant efforts in recent years prototyping high transmit channel-count research platforms [1,2]. In the following, we describe the RF sequencer and RF power amplifier development efforts and present initial bench testing results.