Evaluation of maximum local SAR for parallel transmission (pTx) pulses based on pre-calculated field data using a selected subset of "Virtual Observation Points"
نویسندگان
چکیده
M. Gebhardt, D. Diehl, E. Adalsteinsson, L. L. Wald, and G. Eichfelder Siemens Healthcare, Erlangen, Germany, Siemens Corporate Technology, Erlangen, Germany, Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States, Martinos Center for Biomedical Imaging, Harvard University, Charlestown, MA, United States, Applied Mathematics II, University of Erlangen-Nuremberg, Erlangen, Germany
منابع مشابه
Specific absorption rate studies of the parallel transmission of inner-volume excitations at 7T.
PURPOSE To investigate the behavior of whole-head and local specific absorption rate (SAR) as a function of trajectory acceleration factor and target excitation pattern due to the parallel transmission (pTX) of spatially tailored excitations at 7T. MATERIALS AND METHODS Finite-difference time domain (FDTD) simulations in a multitissue head model were used to obtain B(1) (+) and electric field...
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Introduction Simultaneous multi-slice (SMS) imaging with receiver arrays allows for greatly accelerated 2D single-shot acquisitions with BOLD or diffusionweighted EPI (1-4), and spirals (5). The commonly used SMS excitation methods require specially designed multi-band (MB) (1,2) or PINS RF pulses (6) to excite N slices. In this abstract we explore the use of parallel transmission (pTX) for SMS...
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Purpose—We propose a constrained optimization approach for designing parallel transmit (pTx) pulses satisfying all regulatory and hardware limits. We study the trade-offs between excitation accuracy, local and global SAR, and maximum and average power for small flip-angle pTx (8 channels) spokes pulses in the torso at 3 T and in the head at 7 T. Methods—We compare the trade-offs between the abo...
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