Power Scaling Methods for RF Excitation Fields in MRI Systems
In this paper, we analyze the homogeneity of the transmitted radiofrequency (RF) field by applying different power scaling methods ranging from low-field (12.8 MHz, 0.3 T) to high-field (298 MHz, 7.0 T) magnetic resonance imaging (MRI) systems. Homogeneity strongly depends on RF power scaling, espec...
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The Korean Institute of Electromagnetic Engineering and Science
2025-03-01
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| Series: | Journal of Electromagnetic Engineering and Science |
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| Online Access: | https://www.jees.kr/upload/pdf/jees-2025-2-r-289.pdf |
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| author | Seon-Eui Hong Giuseppe Carluccio Christopher M. Collins Hyung-Do Choi Sukhoon Oh |
| author_facet | Seon-Eui Hong Giuseppe Carluccio Christopher M. Collins Hyung-Do Choi Sukhoon Oh |
| author_sort | Seon-Eui Hong |
| collection | DOAJ |
| description | In this paper, we analyze the homogeneity of the transmitted radiofrequency (RF) field by applying different power scaling methods ranging from low-field (12.8 MHz, 0.3 T) to high-field (298 MHz, 7.0 T) magnetic resonance imaging (MRI) systems. Homogeneity strongly depends on RF power scaling, especially in higher-field MRI. While no notable homogeneity problem is usually observed in lower-field MRI, strong center brightening occurs at a higher field, owing to shortened wavelength. In particular, the dependence of homogeneity on RF power scaling appears during the initial MRI system calibration. In this study, we evaluate the 10-g averaged specific absorption rate (SAR) to evaluate RF safety. This rate may suffer from severe phase interferences, especially in the case of higher-field MRI, due to the increased strength of the static magnetic field and the complex distribution of electrical properties in structures, such as the human head. In particular, the 10-g averaged SAR level is up to six times higher in higher-field MRI with entire-area RF power scaling than with center scaling. Overall, this study establishes the importance of accounting for MRI scan homogeneity and RF safety during MRI examinations. |
| format | Article |
| id | doaj-art-a0930f1fcc8b422bb516df865ede7df8 |
| institution | Kabale University |
| issn | 2671-7255 2671-7263 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | The Korean Institute of Electromagnetic Engineering and Science |
| record_format | Article |
| series | Journal of Electromagnetic Engineering and Science |
| spelling | doaj-art-a0930f1fcc8b422bb516df865ede7df82025-08-20T03:53:46ZengThe Korean Institute of Electromagnetic Engineering and ScienceJournal of Electromagnetic Engineering and Science2671-72552671-72632025-03-0125217518310.26866/jees.2025.2.r.2893734Power Scaling Methods for RF Excitation Fields in MRI SystemsSeon-Eui Hong0Giuseppe Carluccio1Christopher M. Collins2Hyung-Do Choi3Sukhoon Oh4 Terrestrial & Non-terrestrial Integrated Telecommunications Research Lab., Electronics and Telecommunications Research Institute, Daejeon, Korea Department of Electrical and Information Technology of the Universita’ Federico II di Napoli, Napoli, Italy Department of Radiology of New York University, New York, NY, USA Terrestrial & Non-terrestrial Integrated Telecommunications Research Lab., Electronics and Telecommunications Research Institute, Daejeon, Korea MRI Imaging and Translational Research Group, Korea Basic Science Institute, Cheongju, KoreaIn this paper, we analyze the homogeneity of the transmitted radiofrequency (RF) field by applying different power scaling methods ranging from low-field (12.8 MHz, 0.3 T) to high-field (298 MHz, 7.0 T) magnetic resonance imaging (MRI) systems. Homogeneity strongly depends on RF power scaling, especially in higher-field MRI. While no notable homogeneity problem is usually observed in lower-field MRI, strong center brightening occurs at a higher field, owing to shortened wavelength. In particular, the dependence of homogeneity on RF power scaling appears during the initial MRI system calibration. In this study, we evaluate the 10-g averaged specific absorption rate (SAR) to evaluate RF safety. This rate may suffer from severe phase interferences, especially in the case of higher-field MRI, due to the increased strength of the static magnetic field and the complex distribution of electrical properties in structures, such as the human head. In particular, the 10-g averaged SAR level is up to six times higher in higher-field MRI with entire-area RF power scaling than with center scaling. Overall, this study establishes the importance of accounting for MRI scan homogeneity and RF safety during MRI examinations.https://www.jees.kr/upload/pdf/jees-2025-2-r-289.pdfmagnetic resonance imagingpower scalinghomogeneityradiofrequency signalspecific absorption rate |
| spellingShingle | Seon-Eui Hong Giuseppe Carluccio Christopher M. Collins Hyung-Do Choi Sukhoon Oh Power Scaling Methods for RF Excitation Fields in MRI Systems Journal of Electromagnetic Engineering and Science magnetic resonance imaging power scaling homogeneity radiofrequency signal specific absorption rate |
| title | Power Scaling Methods for RF Excitation Fields in MRI Systems |
| title_full | Power Scaling Methods for RF Excitation Fields in MRI Systems |
| title_fullStr | Power Scaling Methods for RF Excitation Fields in MRI Systems |
| title_full_unstemmed | Power Scaling Methods for RF Excitation Fields in MRI Systems |
| title_short | Power Scaling Methods for RF Excitation Fields in MRI Systems |
| title_sort | power scaling methods for rf excitation fields in mri systems |
| topic | magnetic resonance imaging power scaling homogeneity radiofrequency signal specific absorption rate |
| url | https://www.jees.kr/upload/pdf/jees-2025-2-r-289.pdf |
| work_keys_str_mv | AT seoneuihong powerscalingmethodsforrfexcitationfieldsinmrisystems AT giuseppecarluccio powerscalingmethodsforrfexcitationfieldsinmrisystems AT christophermcollins powerscalingmethodsforrfexcitationfieldsinmrisystems AT hyungdochoi powerscalingmethodsforrfexcitationfieldsinmrisystems AT sukhoonoh powerscalingmethodsforrfexcitationfieldsinmrisystems |