Investigation of maximum local specific absorption rate in 7 T magnetic resonance with respect to load size by use of electromagnetic simulations
| Autor: | Agostino Monorchio, Michela Tosetti, M R Symms, Gianluigi Tiberi, Mauro Costagli, Alessandra Retico, Riccardo Stara, Nunzia Fontana, Laura Biagi, Mirco Cosottini |
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| Rok vydání: | 2015 |
| Předmět: |
Physics
medicine.diagnostic_test Physiology fungi Biophysics Tissue heating Specific absorption rate Magnetic resonance imaging General Medicine Computational physics Magnetic field Nuclear magnetic resonance Ultra high frequency Electromagnetic coil Surface coil medicine Radiology Nuclear Medicine and imaging Bioelectromagnetics |
| Zdroj: | Bioelectromagnetics. 36:358-366 |
| ISSN: | 0197-8462 |
| DOI: | 10.1002/bem.21907 |
| Popis: | Local specific absorption rate (SAR) evaluation in ultra high field (UHF) magnetic resonance (MR) systems is a major concern. In fact, at UHF, radiofrequency (RF) field inhomogeneity generates hot-spots that could cause localized tissue heating. Unfortunately, local SAR measurements are not available in present MR systems; thus, electromagnetic simulations must be performed for RF fields and SAR analysis. In this study, we used three-dimensional full-wave numerical electromagnetic simulations to investigate the dependence of local SAR at 7.0 T with respect to subject size in two different scenarios: surface coil loaded by adult and child calves and quadrature volume coil loaded by adult and child heads. In the surface coil scenario, maximum local SAR decreased with decreasing load size, provided that the RF magnetic fields for the different load sizes were scaled to achieve the same slice average value. On the contrary, in the volume coil scenario, maximum local SAR was up to 15% higher in children than in adults. Bioelectromagnetics. 36:358–366, 2015. © 2015 Wiley Periodicals, Inc. |
| Databáze: | OpenAIRE |
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