Tag Archives: hand held

Dr. Emanuel Kanal Recommends Ferromagnetic Detection

If you ever get a chance to hear Dr. Kanal speak, GO! Apart from being Director of MR Services for the University of Pittsburgh Medical Center, a Fellow of both the ISMRM and the ACR, Chair of the ACR’s MR Safety Committee and one of the world’s experts in instruction for the mind-boggling complexity of MR physics, you’ll also find him to be one of the most animated, enthusiastic and downright approachable speakers, ever.

That’s precisely what about 100 – 200 Radiology Administrators at the AHRA Annual Meeting, held just a couple weeks ago in Denver, found out in Dr. Kanal’s MRI Safety Update presentation.

His talk whisked through a number of topics in the brief hour that he had, but one of the chief subjects of his presentation was his enthusiastic support for the use of ferromagnetic detection (FMD) systems as a quality assurance step to assure patient compliance.

At his direction, the University of Pittsburgh Medical Center (UPMC) has purchased 20 Mednovus SAFESCAN® hand-held Target Scanners™, which are in use throughout the UPMC system. Dr. Kanal’s MRI suite is also the ‘proving grounds’ for ferromagnetic detectors from different vendors and he highlighted the use of the Mednovus Entry Sentinel® GS walk-through portal, which is currently being used in a trial to verify screening compliance.

In the coming days and weeks, I hope to share with you specific excerpts from Dr. Kanal’s presentation to the AHRA annual meeting. Suffice it to say that the world’s foremost authority on the breadth of MRI safety issues is a firm believer that MRI-projectile accidents are among the most common source of MRI-related injury – and that ferromagnetic detection can be a remarkably effective tool to help minimize these most frequent safety lapses.

Stay tuned for more information from Dr. Kanal’s presentation, coming soon.

Tobias Gilk, President & MRI Safety Director
Mednovus, Inc.
Tobias.Gilk@Mednovus.com
www.MEDNOVUS.com

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.
Tobias.Gilk@Mednovus.com
www.MEDNOVUS.com

Not ‘Metal Detector’ But ‘Ferromagnetic Detector’

What a metal detector actually does is pretty self-evident by the name of the product… it detects metals. If you’re looking for gold doubloons on the beach or trying to find an underground gas pipe, a conventional metal detector is what you want. But if you’re screening people and objects before they go into the room with the giant magnet at the heart of a magnetic resonance imager (MRI), you’re likely concerned about finding those things  – like pocketknives, cell phones, iron-containing jewelry, wheelchairs, medical gas cylinders, etc… – that can be attracted to the magnet with such force that they can fly across the room.

Click To Read More About What We Look For And What These Instruments Find…