title: Development and evaluation of a small and mobile Magneto Alert Sensor (MALSE) to support safety requirements for magnetic resonance imaging.
abstract: OBJECTIVE
  The purpose of this study is to (i) design a small and mobile Magnetic field ALert SEnsor (MALSE), (ii) to carefully evaluate its sensors to their consistency of activation/deactivation and sensitivity to magnetic fields, and (iii) to demonstrate the applicability of MALSE in 1.5 T, 3.0 T and 7.0 T MR fringe field environments.
  
  
  METHODS
  MALSE comprises a set of reed sensors, which activate in response to their exposure to a magnetic field. The activation/deactivation of reed sensors was examined by moving them in/out of the fringe field generated by 7TMR.
  
  
  RESULTS
  The consistency with which individual reed sensors would activate at the same field strength was found to be 100% for the setup used. All of the reed switches investigated required a substantial drop in ambient magnetic field strength before they deactivated.
  
  
  CONCLUSIONS
  MALSE is a simple concept for alerting MRI staff to a ferromagnetic object being brought into fringe magnetic fields which exceeds MALSEs activation magnetic field. MALSE can easily be attached to ferromagnetic objects within the vicinity of a scanner, thus creating a barrier for hazardous situations induced by ferromagnetic parts which should not enter the vicinity of an MR-system to occur.
authors.affiliation: Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany. conrad.martin@mdc-berlin.de
authors.forename: Conrad
authors.initials: C
authors.lastname: Martin
authors.forename: Tobias
authors.initials: T
authors.lastname: Frauenrath
authors.forename: Celal
authors.initials: C
authors.lastname: Ozerdem
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Renz
authors.forename: Thoralf
authors.initials: T
authors.lastname: Niendorf
mesh_terms: D004574:Electromagnetic Fields; D004867:Equipment Design; D006801:Humans; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics / Q000295:instrumentation; D016272:Occupational Health; D061214:Patient Safety