• Real-time specific absorption...

Treffer: Real-time specific absorption rate supervision for a 32-channel RF transmit system with virtual observation points.

Title:
Real-time specific absorption rate supervision for a 32-channel RF transmit system with virtual observation points.
Authors:
Fiedler TM; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Orzada S; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.; Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany., Grimm JA; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany., Batkai B; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Dinkelacker S; Medical Image Computing, German Cancer Research Center (DKFZ), Heidelberg, Germany., Kratzer FJ; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Klein C; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., May MW; Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.; High-Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany., Mayer F; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Schweins L; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany., Ladd ME; Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.; Erwin L. Hahn Institute for MRI, University Duisburg-Essen, Essen, Germany.; Faculty of Physics and Astronomy, Heidelberg University, Heidelberg, Germany.; Faculty of Medicine, Heidelberg University, Heidelberg, Germany.
Source:
Magnetic resonance in medicine [Magn Reson Med] 2025 Dec; Vol. 94 (6), pp. 2785-2793. Date of Electronic Publication: 2025 Jul 25.
Publication Type:
Journal Article
Language:
English
Journal Info:
Publisher: Wiley Country of Publication: United States NLM ID: 8505245 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1522-2594 (Electronic) Linking ISSN: 07403194 NLM ISO Abbreviation: Magn Reson Med Subsets: MEDLINE
Imprint Name(s):
Publication: 1999- : New York, NY : Wiley
Original Publication: San Diego : Academic Press,
MeSH Terms:
Magnetic Resonance Imaging*/instrumentation , Magnetic Resonance Imaging*/methods, Humans ; Radio Waves ; Equipment Design ; Phantoms, Imaging ; Computer Systems ; Algorithms
References:
Magn Reson Med. 2025 Feb;93(2):842-849. (PMID: 39301784)
PLoS One. 2019 Sep 12;14(9):e0222452. (PMID: 31513637)
Phys Med Biol. 2010 Jan 21;55(2):N23-38. (PMID: 20019402)
Neuroimage. 2018 Mar;168:33-58. (PMID: 28336426)
Magn Reson Med. 2012 Nov;68(5):1664-74. (PMID: 22231647)
Magn Reson Med. 2024 Dec;92(6):2696-2706. (PMID: 39056341)
Magn Reson Med. 2012 May;67(5):1367-78. (PMID: 22139808)
Magn Reson Med. 2004 Apr;51(4):775-84. (PMID: 15065251)
NMR Biomed. 2022 May;35(5):e4656. (PMID: 34962689)
Magn Reson Med. 2021 Jul;86(1):561-568. (PMID: 33634530)
Magn Reson Med. 2011 Nov;66(5):1468-76. (PMID: 21604294)
Magn Reson Med. 2016 Jul;76(1):20-31. (PMID: 26198052)
NMR Biomed. 2021 Jul;34(7):e4515. (PMID: 33942938)
MAGMA. 2021 Feb;34(1):153-163. (PMID: 32964299)
Magn Reson Med. 2017 Feb;77(2):635-643. (PMID: 26888654)
Magn Reson Med. 2025 Dec;94(6):2785-2793. (PMID: 40711974)
Contributed Indexing:
Keywords: GPU acceleration; UHF MRI; VOPs; local SAR; safety supervision
Entry Date(s):
Date Created: 20250725 Date Completed: 20251007 Latest Revision: 20251009
Update Code:
20251009
PubMed Central ID:
PMC12501689
DOI:
10.1002/mrm.30643
PMID:
40711974
Database:
MEDLINE

Weitere Informationen

Purpose: Real-time supervision is a crucial element of an RF parallel transmit (pTx) system to supervise safety of the subject during MR imaging and to utilize the full potential of the RF array. However, the computational demand for the specific absorption rate (SAR) calculation scales much greater than linearly with the number of RF channels. Furthermore, a high number of virtual observation points (VOPs) for the local SAR supervision is preferable to reduce the SAR overestimation during the VOP compression, increasing the computational demand further. An RF transmit supervision system for a 32-channel pTx system including local SAR calculation with a high number of VOPs was developed.
Methods: The system includes 64 digitizer channels to measure the real and imaginary parts of 32 transmit channels. To handle the high computational demand, local SAR calculation is performed on a graphics processing unit (GPU). SAR is averaged for 10 s and 6 min. The system operates independently of the MR system and shuts down the RF power amplifiers (RFPAs) if a SAR limit is exceeded, or the supervision system is interrupted.
Results: The presented system is able to monitor 32 transmit channels and perform real-time SAR calculation with up to 165 000 VOPs. When using only 16 or 8 channels, the number of VOPs increases to 730 000 and 2 300 000, respectively.
Conclusion: In this work, we present a real-time RF supervision system designed to monitor a 32-channel pTx systems including the relative phases of each channel and to perform the local SAR calculation based on VOPs from numerical simulations.
(© 2025 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)