SCIENTISTS at QinetiQ in Malvern have developed a new type of metal detector to prevent accidents at hospital magnetic resonance imager (MRI) suites.

MRI is one of the most useful medical scanners but to do its job, generates a powerful magnetic field.

If any objects made of ferrous metal have accidentally been left lying around, they can fly around dangerously. These accidents are costly, causing injuries to staff and patients, and damage to the expensive equipment.

In one tragic incident three years ago, a child undergoing an MRI examination was killed when hit by a loose oxygen cylinder which got pulled into the machine.

Malvern-based scientist Dr Mark Keene was at a conference in San Diego, California, in 2001 when he heard about this incident - and realised he could do something about it.

Dr Keene, a technical leader in the magnetic sensors department, started by looking at safety procedures already in place at MRI suites.

"All they relied on was staff training and a set of warning stickers about what to take in," he said.

Where metal detectors were in place, they were cumbersome and liable to be set off by any metals, not just the ferrous metals affected by magnetism.

Three years on, the result is QinetiQ's Ferroguard MRI, a cheap device which automatically scans people and goes off if someone tries to pass with ferrous metal objects.

It was launched at the UK Radiological Congress in Manchester last month, and ten units have already been sold in the USA. The same technology is also being applied to the security market.