If you're running an MR suite, here's something you might add to your patient admission arsenal: check for concealed weapons before letting someone enter.

As more and more people feel it necessary to exercise their second amendment right to carry arms, a new gun risk has just popped up: In Indianapolis a veteran allegedly walked into an MR room packing a .45 pistol and it got sucked against the magnet and went off, according to initial reports.

Fortunately his wound was not life-threatening, but it might have been, according to a report in the Indianopolis Star.

The incident took place at Richard L. Roudebush Veterans Affairs Medical Center, which has since walked back the initial statement by an unnamed hospital spokesman that an MR machine was involved, stating only that the firing happened "in a procedure room."

Regardless, with more guns than ever being carried, it is possibly time to revisit standard operating procedures surrounding these powerfully magnetic machines. While this latest incident is apparently the first in which someone was shot, it is not the first time a weapon has gone off in proximity to MR.

A 2002 paper that appeared in the American Journal of Roentgenology reported that an off-duty police officer in Rochester brought his weapon with him when he went for MR imaging. He told the technologist he had the Colt pistol with him and was told to bring the gun with him — with the intention that he would be relieved of the weapon in the patient waiting area so that it could be kept safely by staff until after his exam. A misunderstanding led the officer to enter the MR suite itself with the weapon in his hand.

"Once the officer was inside the MR suite, the gun was pulled from his hand as he attempted to place the gun on top of a cabinet 3 ft (0.9 m) away from the magnet bore. The gun was immediately pulled into the bore, where it struck the left side and spontaneously discharged a round into the wall of the room at the rear of the magnet. Fortunately, no one was injured. Although the gun struck the magnet bore, only minimal cosmetic damage occurred to the magnet itself. The MR unit had full functional capability immediately after the gun discharged. The weapon's thumb safety was reportedly engaged when the gun discharged," according to the case report.

The magnet had to be powered down to remove the gun from its location stuck to an inner wall of the imaging bore.

Examination of the pistol led researchers to suggest that, "the gun likely discharged as a result of the effect of the magnetic field on the firing pin block. The firing pin block was probably drawn into its uppermost position by force of the magnetic field. The firing pin block has to overcome only light pressure from a relatively small spring to release the firing pin."

The advice that comes from this incident suggests that warning signs about weapons, at the very least, should be displayed in proximity to MR machines and that "all radiologists should re-examine our own site's screening methods to ensure that steps are implemented to prevent such a situation from ever recurring."

While adoption of MR has been rising steadily over the past several years, frequency of accidents has grown exponentially. To help improve safety protocols, a group of experts formed the American Board of MR Safety last year to standardize MR protocols and create certification standards to distinguish individuals who practice them.

For more on MR safety read "The rules of attraction: Safety in the MR environment" from the September issue of HCB News magazine