Tag Archives: magnet

More Than Just A Pretty Face…

How I long to be judged for my content… my substance… and not just how I look!

No, not me, the author, but the figurative ‘me‘, this blog…

I don’t know if you’ve ever used them, but all of the major internet search engines have tools that you can use to find images that match your search criteria. Every so often there’s a new paparazzi picture of some starlet in mid-wardrobe-malfunction or a politician with a facial expression that looks like they just smelled something awful that become the ‘it’ picture of the day.

Well, based on the number of hits our blog has been getting recently, and the image search tools that many of these hits are coming from, apparently we have a lesser ‘it’ picture, and it has nothing to do with politics or racy nudity…

It’s a picture of an ICU bed stuck to the face of an MRI.

The 'it' photo of MRI Safety

Pictures of things stuck to magnets often generate wide-eyed looks, even laughter. After all, the juxtaposition can be pretty silly. But each of these pictures is only possible because of horrible mishaps that can each result in serious injury, or even fatality.

We encourage people to find and view these pictures, not to have a larger number of viewers snicker at them. We put them up to help deflate the ‘that could never happen here’ mythology that is dangerous. If you can see magnets, floor polishers, oxygen cylinders, wheelchairs or, as above, ICU beds that look like ones in use at the hospital or imaging center, then maybe the internal monologue becomes something more like, ‘what would have to happen here for us to have a similar accident?’

Most importantly, we hope that all of these efforts work to motivate Technologists, Radiographers, Imaging Managers, Radiologists, Risk-Managers and Compliance Officers to imagine which steps they could take at their locations to reduce the likelihood of these sorts of accidents.

There are many steps that can be taken to help improve the effectiveness of pre-screening for magnet hazards. One of the most obvious is also one of the easiest, the use of ferromagnetic detectors.

We encourage you to view and share the information contained on these pages and we hope that each of these resources, even the racy pictures of MRI missile accidents, help shape improvements to MRI safety at your facilities.

After all, I’m lot more than just a pretty face…

Tobias Gilk, President & MRI Safety Director
Mednovus, Inc.

Inside The Scanner Room? Too Little, Far Too Late!

Many facilities planning for ferromagnetic detectors, particularly existing MRI providers who must retrofit the new technology into tight-fit suite layouts, have a hard time finding optimal locations for the new MRI pre-screening instruments.

Real estate within the outer walls of the hospital is at such a premium that a good proportion of MRI providers are already working within MRI suites into which their large (and frequently growing) operational requirements have been shoehorned-in. They could really do with several hundred additional square feet, so the addition of anything to the suite can trigger a domino series of complications.

Pass-through ferromagnetic detection portals, such as the Mednovus Sentinel® series products, can be sited as either free-standing or doorway-mounted instruments. One caveat for doorway-mounted versions is that the door should not swing through the aperture of the portal (door hardware, even on most RF-shielded doors for MRI suites, has ferromagnetic components and would set off the detector). This means that there is one side of the doorway that is ill-suited to receive a mounted portal.

For MRI suites where space is already at a premium, it is sometimes felt that mounting a ferromagnetic detector at the door into the magnet room is the only place where both existing operations and available space will permit.

But if the door to that room swings out (as is currently recommended by the majority of MRI equipment manufacturers), can you put the detector on the other side of the doorway; on the inside of the MRI scanner room? Physically, yes, you can put the instrument there. Physically, you could also use your MRI scanner room as a waiting area for patients with unknown medical implants and devices, but both ideas would have grave dangers.

The intention of ferromagnetic detection is to alert you to the presence of magnetically attracted materials before they get close to the magnet. Placing a ferromagnetic detector inside the room would only be less effective if were mounted at the face of the bore of the magnet.

Since it often takes a moment to react to the alarm of a ferromagnetic detector, the step or two that a person may take past the ferromagnetic detector isn’t typically a problem outside the MRI scanner room, but in the room where inches can make enormous differences in the magnetically attractive effects, those couple steps can make the difference between avoiding an accident or cleaning-up after one.

Couple the compromised effectiveness with the fact that – at one time or another – everything needs servicing, and you’ve introduced another object into the MRI scanner room that may necessitate servicing from workers with tools. The attempt at increasing safety has actually introduced a new opportunity for accidents.

Lastly, MRI equipment manufactures are (justifiably) nervous about the introduction of equipment into the room which supports the MRI scanner. Does this other equipment emit RF noise that might interfere with the MRI images? Is it going to compromise the function of the scanner? Will the magnetic fields of the scanner adversely effect the other equipment?

In response to these concerns, MRI equipment vendors typically prohibit equipment or devices that haven’t been tested and deemed non-disruptive. Even just placing a ferromagnetic detector inside the MRI scanner room would very likely void significant portions of your MRI manufacturer’s warranty.

The fact is that there are often alternate locations for siting of a pass-through ferromagnetic detectors. It may take a little creative thought or a willingness to slightly modify operational protocols, but typically there are a handful of possibilities for each site. There is no reason – whatsoever – to place a ferromagnetic detector inside the MRI scanning room, and it is extremely ill-advised to do so.

Tobias Gilk, President & MRI Safety Director
Mednovus, Inc.

Do Hand-Held Magnets = Ferromagnetic Detection?

In short, no. Hand-held magnets do not do the same job that ferromagnetic detectors do.

In many MRI facilities, foreign materials brought by people to the MR suite are tested for magnetic field hazards with high strength hand-held magnets. Ones designed specifically for MRI screening are far stronger than the ones holding up my daughter’s artwork on my refrigerator. Some of these ‘test’ magnets can be 1 Tesla at the surface (10,000 gauss)!

Example of hand-held MRI test magnet

These extremely powerful hand-held magnets can help users differentiate between superficial materials that are, and are not, ferromagnetic, but the extraordinary strength of these magnets introduces a number of additional cautions which limit their use.

First, the key word in the paragraph above is ‘superficial.’ The magnetic field of all permanent magnets drops off precipitously (field strength drops with the cube of distance… double the distance and the magnetic field is cut to 1/8th the original value), so permanent magnets will be useful for distinguishing ferromagnetic materials only at or near the surface of an object. Ferromagnetic components below the surface may go undetected by a hand-held magnet, but rest assured that the MRI will find them if those objects make it into the scanner room!

Second, the potential forces exerted on a ferromagnetic body with magnetic field strengths of near 1 Tesla mean that shallow ferromagnetic material within the body of the patient could be moved, perhaps dangerously, by these very strong magnetic forces. But if the purpose of screening is to prevent accidents instead of preemptively causing them, hand-held magnets are poorly suited for patient screening.

Third, if screening medical equipment instead of patients, even some pieces of equipment designed for use in MRI scanner rooms have maximum allowable static and dynamic magnetic field values. Sticking a 1 Tesla magnet all over an anesthesia machine may wind up having some unintended consequences with regard to operation.

Lastly, 1-Tesla magnets stick hard to things. While the hand held magnets aren’t weighty, their magnetic force can require a bit of elbow-grease to get them separated from the cart or medical gas cylinder to which they got stuck. No, it’s not like it becomes epoxied on, but wielding one of these high strength permanent magnets is not a trivial affair.

Each ferromagnetic detection product has its own limitations, so I’m not attempting to state that FMD systems are the perfect solution to the hand-held magnet problem. Hand-held magnets can be useful, in a limited range of uses.

When it comes to the recommendations of the ACR Guidance Document for Safe MR Practices, or the Joint Commission Sentinel Event Alert (#38) on MRI Accidents and Injuries, or the U.S. Veterans Administration’s new MRI Design Guide, the experts all seem to have recognized the benefits of ferromagnetic detection and made a clear distinction between the new technology and the old custom of using permanent magnets to test for safety.

Tobias Gilk, President & MRI Safety Director
Mednovus, Inc.