TY - JOUR A1 - Orzada, Stephan A1 - Solbach, Klaus A1 - Gratz, Marcel A1 - Brunheim, Sascha A1 - Fiedler, Thomas M. A1 - Johst, Sören A1 - Bitz, Andreas A1 - Shooshtary, Samaneh A1 - Abuelhaija, Ashraf A1 - Voelker, Maximilian N. A1 - Rietsch, Stefan H. G. A1 - Kraff, Oliver A1 - Maderwald, Stefan A1 - Flöser, Martina A1 - Oehmingen, Mark A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - A 32-channel parallel transmit system add-on for 7T MRI JF - Plos one Y1 - 2019 U6 - https://doi.org/10.1371/journal.pone.0222452 ER - TY - JOUR A1 - Orzada, Stephan A1 - Bitz, Andreas A1 - Johst, Sören A1 - Gratz, Marcel A1 - Völker, Maximilian N. A1 - Kraff, Oliver A1 - Abuelhaija, Ashraf A1 - Fiedler, Thomas M. A1 - Solbach, Klaus A1 - Quick, Harald H. A1 - Ladd, Mark E. T1 - Analysis of an integrated 8-Channel Tx/Rx body array for use as a body coil in 7-Tesla MRI JF - Frontiers in Physics Y1 - 2017 U6 - https://doi.org/10.3389/fphy.2017.00017 SN - 2296-424X N1 - Article number 17 VL - 5 IS - Jun ER - TY - JOUR A1 - Scholl, Ingrid A1 - Palm, Christoph A1 - Lehmann, Thomas Martin A1 - Spitzer, Klaus T1 - Quantitative Farbmessung in laryngoskopischen Bildern. Palm, C; Scholl, I; Lehmann, TM; Spitzer, K. JF - Bildverarbeitung für die Medizin 1998. Hrsg.: Thomas Lehmann ... Y1 - 1998 SN - 3-540-63885-7 SP - 412 EP - 416 PB - Springer CY - Berlin ER - TY - BOOK A1 - Pettrak, Jürgen T1 - Nutzung nachwachsender Rohstoffe bei der Herstellung thermoplastischer Elastomere aus Folgeprodukten der Olefinmetathese Y1 - 2014 SN - 978-3-942742-35-1 N1 - Nachwachsende Rohstoffe in Forschung und Praxis ; Bd. 4 PB - Attenkofer CY - Straubing ER - TY - JOUR A1 - Fiedler, Thomas M. A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits JF - Medical Physics Y1 - 2017 U6 - https://doi.org/10.1002/mp.12034 N1 - This article is corrected by: Errata: Erratum: “RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus tissue temperature limits” [Med. Phys. 44(1), 143–157 (2017)] Volume 44, Issue 2, 772 VL - 44 IS - 1 SP - 143 EP - 157 ER - TY - JOUR A1 - Dieringer, Matthias A. A1 - Renz, Wolfgang A1 - Lindel, Tomasz Dawid A1 - Seifert, Frank A1 - Frauenrath, Tobias A1 - von Knobelsdorf-Brenkenhoff, Florian A1 - Waiczies, Helmar A1 - Hoffmann, Werner A1 - Rieger, Jan A1 - Pfeiffer, Harald A1 - Ittermann, Bernd A1 - Schulz-Menger, Jeanette A1 - Niendorf, Thoralf T1 - Design and application of a four-channel transmit/receive surface coil for functional cardiac imaging at 7T JF - Journal of Magnetic Resonance Imaging N2 - 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. Y1 - 2011 U6 - https://doi.org/10.1002/jmri.22451 SN - 1522-2586 VL - 33 IS - 3 SP - 736 EP - 741 PB - Wiley-Liss CY - New York ER - 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 - https://doi.org/10.1109/LEMCPA.2020.3029747 VL - 2 IS - 3 SP - 1 EP - 8 PB - IEEE CY - New York, NY ER - TY - RPRT A1 - Ghinaiya, Jagdishkumar A1 - Lehmann, Thomas Martin A1 - Göttsche, Joachim T1 - LOCAL+ – ein kreislauffähiger Holzmodulbau mit nachhaltigem Energie- und Wohnraumkonzept T2 - Bauphysik N2 - Mit dem Beitrag des Teams der FH Aachen zum SDE 21/22 wird im Projekt LOCAL+ ein kreislauffähiger Holzmodulbau mit einem innovativen Wohnraumkonzept geplant und umgesetzt. Ziel dieses Konzeptes ist die Verringerung des stetig steigenden Wohnflächenbedarfs durch ein Raum-in-Raum Konzept. Gebäudetechnisch wird in dem Projekt nicht nur das Einzelgebäude betrachtet, sondern unter Berücksichtigung des Gebäudebestandes wird für das Quartier ein innovatives und nachhaltiges Energiekonzept entwickelt. Ein zentrales Wasserstoffsystem ist für ein Quartier geplant, um den Stromverbrauch aus dem Netz im Winter zu reduzieren. Zentraler Bestandteil des TGA-Konzepts ist ein unterirdischer Eisspeicher, eine PVT und eine Wärmepumpe mit intelligenter Regelstrategie. Ein Teil des neuen Gebäudes (Design Challenge DC) wird in Wuppertal als Hausdemonstrationseinheit (HDU) präsentiert. Eine hygrothermische Simulation der HDU wurde mit der WUFI-Software durchgeführt. Da im Innenraum Lehmmodule und -platten als Feuchtigkeitspuffer verwendet werden, spielen die Themen Feuchtigkeit, Holzfäule und Schimmelwachstum eine wichtige Rolle. KW - Energiekonzept KW - Gesamtwassergehalt KW - Feuchtigkeit KW - Verdunstungskälte KW - energy concept Y1 - 2022 U6 - https://doi.org/10.1002/bapi.202200010 SN - 0171-5445 (Print) SN - 1437-0980 (Online) VL - 44 IS - 3 SP - 136 EP - 142 PB - Ernst & Sohn CY - Hoboken ER - TY - BOOK A1 - Scholl, Ingrid ED - Lehmann, Thomas Martin ED - Spitzer, Klaus T1 - Bildverarbeitung für die Medizin : Algorithmen - Systeme - Anwendungen ; proceedings des Aachener Workshops am 8. und 9. November 1996 / Institut für Medizinische Informatik und Biometrie der RWTH Aachen. Hrsg. von Thomas Lehmann ; Ingrid Scholl ; Klaus Spitzer Y1 - 1996 SN - 3-86073-519-5 PB - Verlag der Augustinus-Buchhandlung CY - Aachen ER - TY - JOUR A1 - Blome, Hans-Joachim A1 - Mashhoon, Bahram T1 - Quasi-normal oscillations of a Schwarzschild black hole JF - Physics Letters A. 100 (1984), H. 5 Y1 - 1984 SN - 0375-9601 SP - 231 EP - 234 ER -