title: Comprehensive RF safety concept for parallel transmission MR.
abstract: OBJECTIVE
  The goal of this study is to increase patient safety in parallel transmission (pTx) MRI systems. A major concern in these systems is radiofrequency-induced tissue heating, which can be avoided by specific absorption rate (SAR) prediction and SAR monitoring before and during the scan.
  
  
  METHODS
  In this novel comprehensive safety concept, the SAR is predicted prior to the scan based on precalculated fields obtained from electromagnetic simulations on different body models. The radiofrequency fields and the global and local SAR are supervised in real time during the scan. This concept is integrated into a 3 T pTx MR scanner and validated experimentally.
  
  
  RESULTS
  Phantom and in vivo experiments successfully validated the basic feasibility of the real-time SAR supervision concept. Supervising the SAR minimizes SAR overestimation. Monitoring the radiofrequency fields allows the detection of unsafe radiofrequency situations for the patient, which a SAR supervision system alone cannot detect.
  
  
  CONCLUSIONS
  This study demonstrates safe scanning in a pTx system. This new safety concept is also applicable for field strengths above 3 T and represents an important step toward safe operation of pTx systems.
authors.affiliation: Department Tomographic Imaging Systems, Philips GmbH Innovative Technologies, Research Laboratories Hamburg, Hamburg, Germany.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Graesslin
authors.affiliation: Department Tomographic Imaging Systems, Philips GmbH Innovative Technologies, Research Laboratories Hamburg, Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Vernickel
authors.affiliation: Department Tomographic Imaging Systems, Philips GmbH Innovative Technologies, Research Laboratories Hamburg, Hamburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Börnert
authors.affiliation: Department Tomographic Imaging Systems, Philips GmbH Innovative Technologies, Research Laboratories Hamburg, Hamburg, Germany.
authors.forename: Kay
authors.initials: K
authors.lastname: Nehrke
authors.affiliation: MR Business Innovation Unit, Philips Healthcare, Best, The Netherlands.
authors.forename: Giel
authors.initials: G
authors.lastname: Mens
authors.affiliation: MR Business Innovation Unit, Philips Healthcare, Best, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Harvey
authors.affiliation: Department Tomographic Imaging Systems, Philips GmbH Innovative Technologies, Research Laboratories Hamburg, Hamburg, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Katscher
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D004869:Equipment Safety / Q000295:instrumentation*; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*
keywords: comprehensive safety concept; parallel transmission; radiofrequency patient safety; specific absorption rate prediction; specific absorption rate supervision; waveform supervision