TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Clemens, Markus
A1  - Bitz, Andreas
T1  - Safety of subjects during radiofrequency exposure in ultra-high-field magnetic resonance imaging
JF  - IEEE Letters on Electromagnetic Compatibility Practice and Applications
N2  - Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques. Since the introduction of MRI in the mid-1980s, there has been a continuous trend toward higher static magnetic fields to obtain i.a. a higher signal-to-noise ratio. The step toward ultra-high-field (UHF) MRI at 7 Tesla and higher, however, creates several challenges regarding the homogeneity of the spin excitation RF transmit field and the RF exposure of the subject. In UHF MRI systems, the wavelength of the RF field is in the range of the diameter of the human body, which can result in inhomogeneous spin excitation and local SAR hotspots. To optimize the homogeneity in a region of interest, UHF MRI systems use parallel transmit systems with multiple transmit antennas and time-dependent modulation of the RF signal in the individual transmit channels. Furthermore, SAR increases with increasing field strength, while the SAR limits remain unchanged. Two different approaches to generate the RF transmit field in UHF systems using antenna arrays close and remote to the body are investigated in this letter. Achievable imaging performance is evaluated compared to typical clinical RF transmit systems at lower field strength. The evaluation has been performed under consideration of RF exposure based on local SAR and tissue temperature. Furthermore, results for thermal dose as an alternative RF exposure metric are presented.
Y1  - 2020
SN  - 2637-6423
U6  - http://dx.doi.org/10.1109/LEMCPA.2020.3029747
VL  - 2
IS  - 3
SP  - 1
EP  - 8
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - CHAP
A1  - Bragard, Michael
A1  - Ronge, C.
A1  - De Doncker, R. W.
T1  - Sandwich design of high-power thyristor based devices with integrated MOSFET structure
T2  - Proceedings of the 2011 - 14th - European Conference on Power Electronics and Applications (EPE 2011) : Aug. 30, 2011 - Sept. 1, 2011, Birmingham, United Kingdom
Y1  - 2011
SN  - 978-1-61284-167-0 (Print)
SN  - 978-90-75815-15-3 (Online)
PB  - IEEE
CY  - Piscataway, NJ
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Bitz, Andreas
T1  - SAR Simulations & Safety
JF  - NeuroImage
Y1  - 2017
U6  - http://dx.doi.org/10.1016/j.neuroimage.2017.03.035
SN  - 1053-8119
IS  - Epub ahead of print
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Gligorevic, Snjezana
A1  - Jost, T.
A1  - Walter, M.
T1  - Scatterer based airport surface channel model
T2  - IEEE/AIAA 28th Digital Avionics Systems Conference : DASC '09 ; 23 - 29 [i.e. 25 - 29] Oct. 2009, Orlando, Fla.
Y1  - 2009
SN  - 978-1-4244-4078-8
SP  - 4C2-1
EP  - 4C2-10
ER  - 
TY  - JOUR
A1  - Heuermann, Holger
A1  - Schiek, Burkhard
T1  - Scattering Parameter Measurements of Microstrip Devices using the Double-LNN Calibration Technique
JF  - Conference proceedings : [Palais des Festivals et des Congrès Cannes, France, 5 - 8 September 1994]
Y1  - 1994
SN  - 0-9518032-5-5
N1  - European Microwave Conference <24, 1994, Cannes>
PB  - Nexus Business Communications
CY  - Swanley
ER  - 
TY  - BOOK
A1  - Gromov, Viacheslav
A1  - Hüning, Felix
T1  - Schnelleinstieg mit dem Renesas RL78/G14 Starter Kit
Y1  - 2015
SN  - 978-3-645-10157-8
PB  - Franzis
CY  - Poing
ER  - 
TY  - BOOK
A1  - Alt, Helmut
A1  - Schumny, Harald
T1  - Schreiben, Zeichnen, Tabellieren : (TI-59, HP-41 C) (Vieweg-Programmbibliothek Taschenrechner ; 4) / Helmut Alt ; Harald Schumny [Hrsg.]
Y1  - 1983
SN  - 3-528-04233-8
PB  - Vieweg + Teubner
CY  - Wiesbaden
ER  - 
TY  - JOUR
A1  - Samm, Doris
A1  - Faissner, H.
A1  - Göttlicher, P.
A1  - Matela, H.
T1  - Search for scalar and pseudoscalar bosons emitted in nuclear decays via their interactions / Faissner, H.; Goettlicher, P. ; Matela, H. ; Samm, D.
JF  - Zeitschrift für Physik A Hadrons and Nuclei. 341 (1992), H. 3
Y1  - 1992
SP  - 359
EP  - 364
ER  - 
TY  - JOUR
A1  - Samm, Doris
A1  - Faissner, H.
A1  - Heinrigs, W.
A1  - Preussger, A.
T1  - Search for the two-photon decay of a light penetrating particle from a 590 MeV proton beam dump / Faissner, H.; Heinrigs, W.; Preussger, A.; Reitz, J.; Samm, D. [u.a.]
JF  - Zeitschrift für Physik, C Particles and Fields. 44 (1989), H. 4
Y1  - 1989
SP  - 557
EP  - 566
ER  - 
TY  - JOUR
A1  - Alt, Helmut
T1  - Sechsunddreißig Spielarten der Verrechung : die Behandlung von Tilgungs- und Zinszahlungen
JF  - Frankfurter Zeitung : Blick durch die Wirtschaft : Zeitung für Finanzen, Steuern, Recht und Management
Y1  - 1989
SP  - vom 12.9.1989
ER  -