When Hampshire-based Qinetiq — one of the world’s leading defence technology companies — developed flux-gate metal detection, the Government was keen to see what the commercial world would make of it.

One of the main target applications was MRI environments in hospitals and clinics. Ferromagnetic objects taken through MRI doors can lead to serious injury, unplanned MRI restarts or MRI damage.

When ferrous objects reach the MRI magnet’s fringe field, they can be attracted strongly and therefore at high speed towards the magnet’s core — a dangerous phenomenon known as ‘the projectile effect’ that has caused 389 ‘events’, including nine deaths, in the past 10 years.

The ferromagnetic detection system, which was developed originally to look for submarines, is ‘unique’ in that it does not generate a magnetic field (as traditional metal detectors do) but senses small changes in the magnetic flux in the environment around it.

It is very sensitive and can be easily tuned to look for different sizes of metal objects; it can also be used in close proximity to hospital MRI scanners, where traditional detectors struggle to compete with the huge magnetic flux that MRIs generate.

To take Ferroguard to market, a Qinetiq spin-out company — Metrasens — was formed. The new company approached the Manufacturing Advisory Service (MAS), which in turn put them in touch with Smallfry — a Coventry-based team of industrial designers and engineers that was already familiar with the capabilities of Bedford-based Midas Pattern Co Ltd (www.midas-pattern.co.uk).

For Ferroguard, Midas designed and produced the pattern equipment, out-sourced the castings and finished them in-house to the high standards demanded for this medical application.

Ultimately, Smallfry managed to turn Metrasens’ metal detection technology prototype unit into a commercial proposition that is protecting patients, staff and equipment in MRI suites across the world. In fact, the product is also successful in a number of civilian security applications, predominantly for metal object spot checks in environments such prisons, shopping malls and theatres.