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@ARTICLE{Fiedler:303192,
      author       = {T. Fiedler$^*$ and S. Orzada$^*$ and J. Grimm$^*$ and B.
                      Batkai$^*$ and S. Dinkelacker$^*$ and F. Kratzer$^*$ and C.
                      Klein$^*$ and M. W. May and F. Mayer$^*$ and L. Schweins$^*$
                      and M. Ladd$^*$},
      title        = {{R}eal-time specific absorption rate supervision for a
                      32-channel {RF} transmit system with virtual observation
                      points.},
      journal      = {Magnetic resonance in medicine},
      volume       = {nn},
      issn         = {1522-2594},
      address      = {New York, NY [u.a.]},
      publisher    = {Wiley-Liss},
      reportid     = {DKFZ-2025-01543},
      pages        = {nn},
      year         = {2025},
      note         = {#EA:E020#LA:E020# / epub},
      abstract     = {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.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.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.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.},
      keywords     = {GPU acceleration (Other) / UHF MRI (Other) / VOPs (Other) /
                      local SAR (Other) / safety supervision (Other)},
      cin          = {E020 / E230},
      ddc          = {610},
      cid          = {I:(DE-He78)E020-20160331 / I:(DE-He78)E230-20160331},
      pnm          = {315 - Bildgebung und Radioonkologie (POF4-315)},
      pid          = {G:(DE-HGF)POF4-315},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:40711974},
      doi          = {10.1002/mrm.30643},
      url          = {https://inrepo02.dkfz.de/record/303192},
}