Assessment of RF Safety of Transmit Coils at 7 Tesla by Experimental & Numerical Procedures

Andreas Klaus Bitz^1,2, Oliver Kraff^1,2, Stephan Orzada^1,2, Stefan Maderwald^1,2, Irina Brote^1,2, Sren Johst^1,2, Mark E. Ladd^1,2

To guarantee safe operation of RF transmit coils during MR examinations, the maximum permitted input power at which SAR limits are not exceeded must be determined. In particular, SAR estimation in high-field MR demands RF simulations with detailed numerical models including transmit coil and heterogeneous human bodies. For validation of the numerical results, an iterative procedure for RF safety testing of transmit coils is proposed which incorporates validation by field measurements in well-defined, canonical test configurations. The proposed test procedure has been applied for safety tests of local and volume coils at 7 Tesla. Results are presented for an 8-channel head and an 8-channel body coil.