From the October 2014 issue of HealthCare Business News magazine
An entryway application involves utilizing a ferromagnetic detection system to monitor and screen individuals and items attempting to enter an MR suite, or scanner room. Therefore, it is very common for the ferromagnetic detection system to be mounted at the door jamb of the entry point to Zone 3 or Zone 4. Depending on the layout and operation of an MR suite, it may not be practical to provide the entryway mass screener at the entrance to Zone 3, even though this is the preferred location. In nearly all situations, however, a solution can be found in which the FMDS is placed at the entrance to either Zone 3 or Zone 4.
A third application would be a combination of prescreen and entryway screening systems. Utilizing both applications ensures that patients have been thoroughly screened prior to entering the suite. It also ensures that the magnet room itself has additional protection from anyone that may enter the suite, including those previously identified as likely getting around the standard screening process.
Depending on the sitting conditions, including the location and swing direction of the door, selecting a proper product and installation location for an entryway application requires some careful consideration. Doors, even RF shielded doors at the entrance to Zone 4, contain ferrous material, which can lead to unintended positive indications on a ferromagnetic detection system if the door is in motion as someone passes through the system. The obvious solution would be to use a ferrous-free door, but unfortunately. Even an aluminum (or other non-ferromagnetic material) door would create a phenomena known as “eddy currents” when it opened or closed, which would trigger a sufficiently sensitive FMDS.
Design guidelines for a ferromagnetic detection system
In order for a mass screener ferromagnetic detection system to be effective, the users and site designers can consider several options. The first and most ideal option is to layout the suite with the implementation of a ferromagnetic detection system planned into the site layout. In an ideal situation, the planners would be able to create an entryway hall or partition wall that leads to the magnet room. An entryway that extends several feet away from the entrance allows patients and staff to pass through the entry way prior to opening the magnet room door, which will limit the possibility of false positives generated by door motion. As many sites are in existence and many others lack the space needed to implement such an option, a second option of proper training and safety protocols can be utilized to avoid the potential of incidental alarms from door movement. For example, as part of the protocols for entering the room, staff can first open the door prior to allowing patients to pass through the room. Once the door is open and no longer in motion, it would be possible for individual to pass through the ferromagnetic detection system for an appropriate screening without any interference from door motion.
