| Zugriffsnummer | 31493 |
| Dokumenttyp | Konferenzartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Reliable and robust RF safety assessment of transmit array coils at ultrahigh fields |
| Autor(in); Institution |
Seifert, Frank; 8.1, Medizinische Messtechnik, PTB-Berlin
Cassara, Antonino; 8.1, Medizinische Messtechnik, PTB-Berlin
Weidemann, Gerd; 8.1, Medizinische Messtechnik, PTB-Berlin
Ittermann, Bernd; 8.1, Medizinische Messtechnik, PTB-Berlin
|
| Quelle/Jahr | ISMRM 22th annual meeting & exhibition: 10-16 May 2014; Milan, Italy:(2014), 4891 |
| Availability | [CD-ROM] ; file name: 4891.pdf |
| Konferenzangaben | ISMRM 22th Scientific Meeting of the International Society for Magnetic Resonance in Medicine, Milano, 10-16, May, 2014, Italy |
| Zusammenfassung | We developed a procedure to find an upper limit for the local SAR10g from the Q-matrix of transmit array coils. When applying this procedure to a 7T 8-channel transmit head coil the resulting local SAR related power limit is only 25 % lower than the forward power limit for the head SAR which has to be obeyed anyway. This holds for both voxel models used ('Duke' and 'Ella') and thus allows the easy and safe use of the coil without substantial loss in performance. It appears questionable whether the remaining room for improvement justifies the effort of dedicated hardware, software and sequences for on-the-fly SAR calculations. This holds especially as such dedicated hard- and software is inaccessible and its correct performance cannot be tested or evaluated by the user. Care has to be taken when using a Butler matrix in conjunction with the array coil. Since a Butler matrix allows for coherent voltage superposition of all channels the local SAR can be ) 1.5 times higher than without Butler matrix. |
Zitierung
Seifert, F., Cassara, A., Weidemann, G., & Ittermann, B. (2014). Reliable and robust RF safety assessment of transmit array coils at ultrahigh fields. ISMRM 22th Scientific Meeting of the International Society for Magnetic Resonance in Medicine, Milano, 10-16, May, 2014, Italy.