Medicines and Healthcare Products Regulatory Agency
The UK regulatory agency recognizes FERROMAGNETIC DETECTORS

5.4.11 Ferromagnetic detectors
A number of ferromagnetic material detectors are now available. The ferromagnetic
detection systems have a number of advantages over conventional metal detectors including being totally passive systems and allowing non-ferrous metal objects to pass by without alarming.

Ferromagnetic detection systems are designed to be operated in two different modes; for pre-screening patients or for guarding the scan room entryway. In the pre-screening mode
the system is typically located in the changing room area and will allow a patient to be scanned for small ferrous items well in advance of entering the scan room.

As well as reducing the likelihood of small projectile incidents, the systems are designed to reduce the likelihood of an MRI scan having to be repeated e.g. due to the presence of an object distorting the MRI scan image. In the MRI entryway protection mode the ferromagnetic detection system would be located at the entrance to the MRI suite. It is placed or mounted either side or the doorway and as such presents no obstruction to entry into the scan room. The detection sensitivity is somewhat lower than a pre-screen mode and the systems are designed to reduce the likelihood of a major ‘projectile effect’ incident.

Ferromagnetic detection systems are intended as ancillary screening devices and are not intended to be used as a replacement for traditional safety programmes, training or primary screening methods.

MHRA DB2007(03) December 2007, Page 72/104

The entire paper can be accessed through these links:
http://www.mhra.gov.uk/home/idcplg?IdcService=SS_GET_PAGE&useSecondary=true&ssDocName=CON2033018&ssTargetNodeId=834