MRI Safety Zones and more 3

What is the purpose of the MRI Safety Zone system?

To restrict access to the magnet room and define safety boundaries based on distance from the MRI scanner.

How many MRI safety zones exist and how are they ordered?

Four zones, numbered 1 through 4, from least to most restrictive.

What does the MRI magnetic field extend through?

It extends in three dimensions and may reach into other rooms or floors of the facility.

What is Zone One in MRI safety?

The area freely accessible to the public, such as entrances and common areas; no magnetic hazard is present.

What is Zone Two in MRI safety?

A buffer between Zone One and Zone Three where patients are under general supervision of MRI personnel.

What areas may be included in Zone Two?

The MRI reception area, dressing rooms, and interview rooms.

Is there magnetic influence in Zone Two?

No, Zone Two is safe from the powerful magnetic field.

What is Zone Three in MRI safety?

An area restricted by a physical barrier where only approved MRI personnel and screened patients are allowed.

What is located within Zone Three?

The MRI control room and/or computer room.

Does Zone Three include magnetic influence?

Yes, magnetic influence is present, but Zone Three ends outside the 5-gauss line.

What is Zone Four in MRI safety?

The MRI scanner room itself, also called the magnet room.

How can one access Zone Four?

Access is only possible through Zone Three; there is no direct entrance from public areas.

Where is the 5-gauss line located?

Inside Zone Four.

What are Zones Three and Four sometimes collectively called?

The MRI Suite.

Who must be screened before entering the MRI Suite?

Anyone entering, including patients and staff, must be screened for unsafe medical devices or implants.

Why must patients with medical devices be screened?

Because the magnetic field and RF pulses can cause device malfunction or heating of implanted leads.

What can RF pulses in MRI cause with conductive leads?

They can induce electrical current, leading to heating and burns.

What are examples of unsafe medical devices in MRI?

Pacemakers, defibrillators, cochlear implants, aneurysm clips, implanted drug pumps, and neurostimulators.

What can happen to metallic surgical clips or staples in MRI?

They may torque or move due to magnetic forces, causing tissue damage.

Why is metal in the eye dangerous in MRI?

Because it can move or heat up, causing serious injury to the eye.

What is being done to improve MRI safety for patients with implants?

Manufacturers are producing more MRI-safe devices each year.

What should be done when a patient reports an implant?

The technologist should verify the implant’s safety status; many patients carry an implant card with detailed information.

What are the three MRI device safety classifications?

MRI Safe, MRI Conditional, and MRI Unsafe.

What does MRI Safe mean?

The device is always safe in all MRI environments.

What does MRI Conditional mean?

The device is safe under certain specified conditions.

What does MRI Unsafe mean?

The device is not safe and should never be used or brought into the MRI environment.

What must be done for patients who require monitoring during an MRI scan?

They must be disconnected from regular monitoring equipment and connected to MRI-safe equipment.

What should be done during a code blue (cardiac arrest) in the MRI suite?

Remove the patient from Zone Four and move them into Zone Two before resuscitation.

What must be done in the event of a fire in the MRI room?

The magnet must be quenched to allow firefighters access, and everyone must evacuate immediately.

What happens during an MRI magnet quench?

The magnetic field is shut down by releasing cryogenic gases that cool the superconducting coils.

Why is a magnet quench dangerous?

Because cryogenic gases can displace oxygen in the room and be deadly if not properly vented.

Why are magnets almost never turned off?

Because quenching is extremely expensive and potentially hazardous due to the release of cryogenic gases.

What are the most common patient injuries in the MRI suite?

Burns caused by heated leads, wires, or conductive materials.

What are examples of objects that may cause burns in MRI?

Wires, leads, pulse oximeter sensors, monitor cables, safety pins, metal clamps, drug delivery patches, and tattoos containing iron oxide.

What are the most common sources of projectile incidents in MRI?

Cleaning tools or maintenance equipment accidentally brought into the magnet room.

Why do MRI projectile incidents often occur?

Because staff such as housekeeping or maintenance workers may be unaware that the MRI magnet is always on.