MRI Safety Protocols: What You Need to Know for the ARRT Exam

MRI safety questions show up all over the registry exam. They're testing whether you actually understand why certain things are dangerous around a giant magnet - not just if you memorized a list.

Know Your Safety Zones

The ACR breaks down MRI areas into four zones. You need to know these:

Zone I is just public space. Waiting rooms, hallways. No restrictions.

Zone II is where you screen patients before they go anywhere near the magnet. This is where you catch the guy who forgot to mention his pacemaker.

Zone III is restricted. Only MRI staff and screened patients. The magnetic field might already be present here.

Zone IV is the scan room. The magnet is live 24/7, even when you're not scanning. This is where bad things happen if you're not careful.

Patient Screening Isn't Optional

Every patient gets screened. Every time. No exceptions. The exam wants you to know what's an absolute no-go and what might be okay with precautions.

Absolute contraindications: Most pacemakers (unless they're specifically MRI-safe), certain old aneurysm clips, some cochlear implants, metal fragments in the eye. If they have any of these, they're not getting scanned.

Relative contraindications need judgment calls. First trimester pregnancy? Maybe wait unless it's urgent. Claustrophobia? You can work with that. Some prosthetics? Depends on the type.

Everything Becomes a Missile

Here's what people don't get until they see it - ferromagnetic objects don't just stick to the magnet. They fly. Fast. Oxygen tanks, clipboards, mop buckets, scissors. There are horror stories of chairs and IV poles getting sucked into the bore. Know which materials are safe (titanium, most aluminum) and which aren't (steel, iron, nickel).

RF Burns Are Real

SAR - Specific Absorption Rate - measures how much radiofrequency energy gets absorbed by tissue. Too much and you're literally heating up the patient. The FDA has limits. Higher field strength, certain sequences, larger patients - all increase SAR. You need to know when to back off.

When to Hit the Emergency Button

Quenching the magnet means releasing all the helium at once. It's loud, it's expensive, and it displaces oxygen in the room. You only do this in a true life-or-death emergency - like someone's trapped and you can't get them out. If it happens, everyone evacuates immediately.

The exam tests whether you understand the why behind these rules, not just the rules themselves. Know the physics, know the risks, and you'll handle these questions fine.

Test your safety knowledge with our MRI Safety Practice Quiz.

Written by Pass MR