4 Zones: Implementing Safety In Your MRI Suite.

(Reprinted from MRI Newsletter, April 2005)

“Four zones! I barely have four rooms!” So goes the lament of many diagnostic imaging facilities. Sadly, this is even true for many designed after the American College of Radiology’s White Paper on MR Safety was published.

Hospital space tends to be at such a premium, both in terms of cost and scarcity, that no department is immune from pressures to squeeze out every possible square foot. Many real-world MRI suites are only scale models of what they ought to be, every function corseted far too tightly to function efficiently. Scanners shoe-horned into walk-in closets, waiting rooms where patients pack in like sardines, patients and staff crashing into each other… any of this sound familiar?

And it is into this situation that the ACR releases the White Paper on MR Safety which indicates that every MRI facility should provide sequential zones of screening and access control. Surely there are imaging administrators out there thinking that a job with the bomb squad would be less tense. But, alas, there is good news!

If MRI safety weren’t already self-justifying, there are several good reasons to implement the ACR’s 4-zone principles…

  • It’s actually relatively easy to do
  • It can be done with minimal expenditure
  • It can actually improve patient throughput

First, the 4-zone principle doesn’t actually require four zones in the MRI suite. My office is in your Zone 1. So is the bus stop on the corner, the airport across the river, and my mom’s house across the state. Essentially, Zone 1 is everywhere your magnet isn’t. It’s the outside world. So your facility really only needs to provide three of the four zones.

Working from the other end, your magnet room is Zone IV. So now you only need to provide two spaces between your magnet room and the outside world. This can be made up of waiting rooms, screening areas, change rooms, prep areas, patient holding bays, control room. Surely you have two rooms between the magnet and the rest of the world!

This is not to say that every MRI suite that has at least three rooms meets the 4-Zone standard or that you even need to have walls to differentiate all of your zones.

The core of the 4-Zone principle is that, as you progress towards the magnet room you undergo increasing levels of screening and observation to prevent incidents that could threaten the safety of patients and staff. A hundred-room MRI suite without screening and access controls won’t comply with the 4-Zone principle, but a two room suite with stanchions with velvet ropes and a clearly indicated path of sequential screening could comply with the principle.

Which brings us to our second point, applying the 4-Zone principles doesn’t have to cost much. One or two strategically placed locking doors may be able to help your facility improve safety and meet the intention of the ACR. And, in fact, they don’t even have to necessarily be doors. You could run down to Home Depot and put a fence where you need access controls (building code permitting).

The cost of a new door can be only a few hundred dollars. Perhaps a new wall, plus a door, plus a couple coats of paint would be a few thousand dollars. Think of this as 30 minutes of scanner time reinvested to improve safety for the life of your facility.

Do make sure that any access control devices you provide are in full compliance with all applicable codes. Adding a locked door to improve MRI suite safety is counterproductive if it also traps occupants inside the building during a fire. It is often very smart to bring in an architect to help evaluate the life-safety implications of new access control doorways and locks. In most municipalities, it will actually be required.

Our last point is that the ACR 4-Zone principle can actually improve patient throughput. Unfortunately, this isn’t automatic. It’s not as if putting a supercharger on a station wagon will turn it into a dragster. Similarly, dropping a door or a wall into your MRI suite won’t, by themselves, improve efficiency.

But if you look at the 4-Zone principle as a process, a methodology for screening and preparing patients for their scans, you can think best about how to implement it to work with your patients, your facility and your operations. When well thought out, these improvements should have no negative effects on patient throughput. In fact, when seen as an enhancement to your process, a well laid out suite can increase screening efficiency and reduce the number of missed ferrous objects that, minimally, take time from patient scanning.

So, ultimately you don’t need a 10,000 square foot imaging department to employ the ACR 4-Zone principle. It doesn’t require a million-dollar budget or months of agonizing committee meetings. It can be simple and inexpensive to implement and, if done with a touch of forethought, can improve the performance of your MRI suite. In short, there is no good reason to not implement it!

By Tobias Gilk, M.Arch


(please follow us on Twitter, too. http://twitter.com/RADplanning)

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4 Responses to 4 Zones: Implementing Safety In Your MRI Suite.

  1. Diane Gibford says:

    In regards to safety in the MRI suite, the ACR guidelines say zone 3 should be restricted. Does restricted have to be a locked door or when the MRI technologist is present can it be restricted by a sign across doorway with chain physically stopping entrance into the zone?

    • RAD-Editor says:

      Great question, Diane! You’re getting deep into the interpretation of the 4-Zone principles. In general, my personal opinion would be that as long as (1) there was a clear barrier between Zone II and Zone III that was unambiguous about the fact that unauthorized people were not to proceed beyond, and (2) the technologist had direct and immediate situational awareness to be able to see if the ‘soft’ barrier (e.g. a rope across an open doorway) has been defeated.

      So, if the tech is at the console and can see the doorway from Zone II into Zone III, then AT THAT TIME, the soft barrier would be sufficient. However, if the tech goes into the magnet room, and loses situational awareness of that doorway, then I would consider that a collapse of the Four Zone.

      I hope this helps.

      Tobias Gilk

  2. didi says:

    Please forgive me for my bad english, i would like to ask you about a certain condition in my hospital… in the hospital lounge, which is located somewhere above the MRI room, you can still hear the sound of the MRI machine when it’s working, in that situation is it safe to stay and spend quite a lot of time in that lounge ? thank you for your reply….

    • RAD-Editor says:


      It is possible that the sound levels are disruptive, but it is unlikely that they are loud enough to be damaging with short-term use of the lounge. Hearing the operation of the MRI unit, however, is no indication that there are any other safety problems. It probably is an indication of poor design and construction, though.

      I hope this helps.

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