Andreas Klaus Bitz1,2, Irina Brote1,2, Stephan Orzada1,2, Oliver Kraff1,2, Stefan Maderwald1,2, Harald H. Quick1,2, Pedram Yazdanbakhsh3, Klaus Solbach3, Achim Bahr4, Thomas Bolz4, Karsten Wicklow5, Franz Schmitt5, Mark E. Ladd1,2
1Erwin L. Hahn Institute for MRI, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; 3University Duisburg-Essen, Duisburg, Germany; 4IMST GmbH, Kamp-Lintfort, Germany; 5Siemens Healthcare, Erlangen, Germany
An 8-channel add-on system for RF shimming was integrated into a 7 T whole-body MR scanner to enable research on the limits and benefits of RF shimming in various body regions. The system allows computer-controlled setting of amplitude and phase of each transmit channel by use of inexpensive vector modulators on the small-signal side of the system. Real-time supervision of the transmitted RF power was implemented to guarantee operation within the limits given in the IEC safety guidelines. The shimming system has already been successfully utilized for MRI of the human head, the abdomen, and thorax.