@article{OrzadaBitzJohstetal.2017,
  author    = {Orzada, Stephan and Bitz, Andreas and Johst, S{\"o}ren and Gratz, Marcel and V{\"o}lker, Maximilian N. and Kraff, Oliver and Abuelhaija, Ashraf and Fiedler, Thomas M. and Solbach, Klaus and Quick, Harald H. and Ladd, Mark E.},
  title     = {Analysis of an integrated 8-Channel Tx/Rx body array for use as a body coil in 7-Tesla MRI},
  series = {Frontiers in Physics},
  volume    = {5},
  journal   = {Frontiers in Physics},
  number    = {Jun},
  issn      = {2296-424X},
  doi       = {10.3389/fphy.2017.00017},
  year      = {2017},
  language  = {en}
}
@article{SchollPalmLehmannetal.1998,
  author    = {Scholl, Ingrid and Palm, Christoph and Lehmann, Thomas Martin and Spitzer, Klaus},
  title     = {Quantitative Farbmessung in laryngoskopischen Bildern. Palm, C; Scholl, I; Lehmann, TM; Spitzer, K.},
  series = {Bildverarbeitung f{\"u}r die Medizin 1998. Hrsg.: Thomas Lehmann ...},
  journal   = {Bildverarbeitung f{\"u}r die Medizin 1998. Hrsg.: Thomas Lehmann ...},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {3-540-63885-7},
  pages     = {412 -- 416},
  year      = {1998},
  language  = {en}
}
@article{FiedlerLaddBitz2017,
  author    = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas},
  title     = {RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits},
  series = {Medical Physics},
  volume    = {44},
  journal   = {Medical Physics},
  number    = {1},
  doi       = {10.1002/mp.12034},
  pages     = {143 -- 157},
  year      = {2017},
  language  = {en}
}
@article{DieringerRenzLindeletal.2011,
  author    = {Dieringer, Matthias A. and Renz, Wolfgang and Lindel, Tomasz Dawid and Seifert, Frank and Frauenrath, Tobias and von Knobelsdorf-Brenkenhoff, Florian and Waiczies, Helmar and Hoffmann, Werner and Rieger, Jan and Pfeiffer, Harald and Ittermann, Bernd and Schulz-Menger, Jeanette and Niendorf, Thoralf},
  title     = {Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T},
  series = {Journal of Magnetic Resonance Imaging},
  volume    = {33},
  journal   = {Journal of Magnetic Resonance Imaging},
  number    = {3},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1522-2586},
  doi       = {10.1002/jmri.22451},
  pages     = {736 -- 741},
  year      = {2011},
  abstract  = {Purpose To design and evaluate a four-channel cardiac transceiver coil array for functional cardiac imaging at 7T. Materials and Methods A four-element cardiac transceiver surface coil array was developed with two rectangular loops mounted on an anterior former and two rectangular loops on a posterior former. specific absorption rate (SAR) simulations were performed and a Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-1 calibration method was applied prior to obtain 2D FLASH CINE (mSENSE, R = 2) images from nine healthy volunteers with a spatial resolution of up to 1 × 1 × 2.5 mm3. Results Tuning and matching was found to be better than 10 dB for all subjects. The decoupling (S21) was measured to be >18 dB between neighboring loops, >20 dB for opposite loops, and >30 dB for other loop combinations. SAR values were well within the limits provided by the IEC. Imaging provided clinically acceptable signal homogeneity with an excellent blood-myocardium contrast applying the Burn:x-wiley:10531807:media:JMRI22451:tex2gif-stack-2 calibration approach. Conclusion A four-channel cardiac transceiver coil array for 7T was built, allowing for cardiac imaging with clinically acceptable signal homogeneity and an excellent blood-myocardium contrast. Minor anatomic structures, such as pericardium, mitral, and tricuspid valves and their apparatus, as well as trabeculae, were accurately delineated.},
  language  = {en}
}
@article{FiedlerLaddClemensetal.2020,
  author    = {Fiedler, Thomas M. and Ladd, Mark E. and Clemens, Markus and Bitz, Andreas},
  title     = {Safety of subjects during radiofrequency exposure in ultra-high-field magnetic resonance imaging},
  series = {IEEE Letters on Electromagnetic Compatibility Practice and Applications},
  volume    = {2},
  journal   = {IEEE Letters on Electromagnetic Compatibility Practice and Applications},
  number    = {3},
  publisher = {IEEE},
  address   = {New York, NY},
  isbn      = {2637-6423},
  doi       = {10.1109/LEMCPA.2020.3029747},
  pages     = {1 -- 8},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{BlomeMashhoon1984,
  author    = {Blome, Hans-Joachim and Mashhoon, Bahram},
  title     = {Quasi-normal oscillations of a Schwarzschild black hole},
  series = {Physics Letters A. 100 (1984), H. 5},
  journal   = {Physics Letters A. 100 (1984), H. 5},
  isbn      = {0375-9601},
  pages     = {231 -- 234},
  year      = {1984},
  language  = {en}
}
@article{HoehrPaulssenBenardetal.2014,
  author    = {Hoehr, Cornelia and Paulßen, Elisabeth and Benard, Francois and Lee, Chris Jaeil and Hou, Xinchi and Badesso, Brian and Ferguson, Simon and Miao, Qing and Yang, Hua and Buckley, Ken and Hanemaayer, Victoire and Zeisler, Stefan and Ruth, Thomas J. and Celler, Anna and Schaffer, Paul},
  title     = {⁴⁴ᶢSc production using a water target on a 13 MeV cyclotron},
  series = {Nuclear medicine and biology},
  volume    = {41},
  journal   = {Nuclear medicine and biology},
  number    = {5},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1872-9614},
  doi       = {10.1016/j.nucmedbio.2013.12.016},
  pages     = {401 -- 406},
  year      = {2014},
  abstract  = {Access to promising radiometals as isotopes for novel molecular imaging agents requires that they are routinely available and inexpensive to obtain. Proximity to a cyclotron center outfitted with solid target hardware, or to an isotope generator for the metal of interest is necessary, both of which can introduce significant hurdles in development of less common isotopes. Herein, we describe the production of ⁴⁴Sc (t₁⸝₂ = 3.97 h, Eavg,β⁺ = 1.47 MeV, branching ratio = 94.27\%) in a solution target and an automated loading system which allows a quick turn-around between different radiometallic isotopes and therefore greatly improves their availability for tracer development. Experimental yields are compared to theoretical calculations.},
  language  = {en}
}
@article{FiedlerLaddBitz2017,
  author    = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas},
  title     = {SAR Simulations \& Safety},
  series = {NeuroImage},
  journal   = {NeuroImage},
  number    = {Epub ahead of print},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1053-8119},
  doi       = {10.1016/j.neuroimage.2017.03.035},
  year      = {2017},
  language  = {en}
}
@article{OrzadaFiedlerBitzetal.2020,
  author    = {Orzada, Stephan and Fiedler, Thomas M. and Bitz, Andreas and Ladd, Mark E. and Quick, Harald H.},
  title     = {Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance},
  series = {Magnetic Resonance Materials in Physics, Biology and Medicine},
  journal   = {Magnetic Resonance Materials in Physics, Biology and Medicine},
  number    = {34 (2021)},
  publisher = {Springer},
  address   = {Heidelberg},
  isbn      = {1352-8661},
  doi       = {10.1007/s10334-020-00890-0},
  pages     = {153 -- 164},
  year      = {2020},
  abstract  = {Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20\% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission.},
  language  = {en}
}
@article{GraesslRenzHezeletal.2013,
  author    = {Gr{\"a}ßl, Andreas and Renz, Wolfgang and Hezel, Fabian and Dieringer, Matthias A. and Winter, Lukas and {\"O}zerdem, Celal and Rieger, Jan and Kellmann, Peter and Santoro, Davide and Lindel, Tomasz Dawid and Frauenrath, Tobias and Pfeiffer, Harald and Niendorf, Thoralf},
  title     = {Modular 32-channel transceiver coil array for cardiac MRI at 7.0T},
  series = {Magnetic Resonance in Medicine},
  volume    = {72},
  journal   = {Magnetic Resonance in Medicine},
  number    = {1},
  publisher = {Wiley-Liss},
  address   = {New York},
  issn      = {1522-2594},
  doi       = {10.1002/mrm.24903},
  pages     = {276 -- 290},
  year      = {2013},
  abstract  = {Purpose To design and evaluate a modular transceiver coil array with 32 independent channels for cardiac MRI at 7.0T. Methods The modular coil array comprises eight independent building blocks, each containing four transceiver loop elements. Numerical simulations were used for B1+ field homogenization and radiofrequency (RF) safety validation. RF characteristics were examined in a phantom study. The array's suitability for accelerated high spatial resolution two-dimensional (2D) FLASH CINE imaging of the heart was examined in a volunteer study. Results Transmission field adjustments and RF characteristics were found to be suitable for the volunteer study. The signal-to-noise intrinsic to 7.0T together with the coil performance afforded a spatial resolution of 1.1 × 1.1 × 2.5 mm3 for 2D CINE FLASH MRI, which is by a factor of 6 superior to standardized CINE protocols used in clinical practice at 1.5T. The 32-channel transceiver array supports one-dimensional acceleration factors of up to R = 4 without impairing image quality significantly. Conclusion The modular 32-channel transceiver cardiac array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0T.},
  language  = {en}
}