Building an MRI Safety Program: Zones, Roles, and the 2024 ACR Manual Update

Introduction

An MRI safety program is the documented system of zones, trained personnel, screening procedures, and written policies that a facility uses to control four invisible and continuously present hazards: the static magnetic field, radiofrequency (RF) heating, switched gradient fields, and cryogen quench. Unlike X-ray or CT, where the radiation hazard exists only while the beam is on, the MRI magnet is always on — even during a power failure — which is exactly why MRI safety depends on engineered space, trained people, and disciplined process rather than a power switch.

The current national template for that system is the 2024 ACR Manual on MR Safety, published June 11, 2024, which reorganized the guidance into a chapter format and refreshed several practical elements: personnel training levels, staffing for routine, emergency, and remote scanning, a strengthened "full stop / final check" before entering the magnet room, pocketless attire and equipment tethering, a new pathway for patients with unclear or unlabeled implants, and a site policy checklist ^{1, 2}.

At the same time, the accreditation landscape moved. On January 1, 2026, the Joint Commission's new National Performance Goals (NPG) chapter replaced the long-standing National Patient Safety Goals, and NPG #13, "Protecting Patients and Providers in Imaging," now houses the MRI, CT, and fluoroscopy safety expectations hospitals already had to meet ⁵. This article explains how to build an MRI safety program that satisfies both — and where a board-certified medical physicist fits as your MR Safety Expert. Diagnostic Radiation Physics Services (DRPS) supports imaging programs across Florida, Maryland, Virginia, Washington DC, California, and Nevada.

Why This Topic Matters

MRI safety failures are rarely subtle — they are projectiles, burns, and quenches that injure patients and staff in seconds — and almost all of them trace back to a gap in zones, screening, or training rather than equipment failure. A ferromagnetic oxygen cylinder, a forgotten implanted device, or an unscreened visitor in the magnet room can turn a routine exam into a serious safety event.

That is also why MRI safety is increasingly written into accreditation and patient-safety frameworks. The updated National Quality Forum serious reportable events list now names MR Zone IV safety events and MRI-related thermal injury explicitly, and some of these may qualify regardless of whether the patient is injured — the focus is on the integrity of access control and screening, not just the outcome. We covered that shift in Sentinel Events vs Serious Reportable Events. A credible MRI safety program is now both a clinical necessity and an accreditation expectation.

Topic Explanation

The four-zone model

The backbone of every MRI safety program is the ACR four-zone model, which uses physical space and access control to keep unscreened people and ferromagnetic objects away from the magnet ¹. Each zone represents an increasing level of restriction:

Zone I — Freely accessible public space outside the MR environment (parking, general corridors). No MR-related screening is required, and anyone may be present.
Zone II — The interface between the public Zone I and the controlled Zones III and IV. Patients are greeted, their histories and screening forms are obtained, and they move only under the supervision of MR Personnel. This is where the screening conversation happens.
Zone III — A restricted region where free access by unscreened Non-MR Personnel or ferromagnetic objects can result in serious injury or death. Access is physically controlled (locked doors, badge or key access) and supervised exclusively by Level 2 MR Personnel.
Zone IV — The scanner magnet room itself. It is always located within Zone III, is marked with MR warning signage and an illuminated indicator that the magnet is on, and represents the highest-risk area for projectile and quench events.

The zones are not just signage. They are an engineered control: the boundary between Zone II and Zone III is the single most important line in the department, and it should never be crossed without screening and supervision.

The three safety roles

The 2024 manual organizes accountability around three named roles — the MR Medical Director (MRMD), the MR Safety Officer (MRSO), and the MR Safety Expert (MRSE) — so that medical, operational, and technical responsibility each has a clear owner ¹.

MR Medical Director (MRMD) — A physician who holds overall accountability for the MR safety program, sets policy, and makes the final medical decisions on complex cases.
MR Safety Officer (MRSO) — The person who implements the program day to day, usually a senior MRI technologist functioning at Level 2. The MRSO oversees screening, access control, staff competency, and incident follow-up.
MR Safety Expert (MRSE) — The scientific and technical authority, typically a medical physicist, who handles "the real nuts and bolts of the physics": adjudicating implant conditionality, field strength, spatial gradient, RF/SAR, and gradient-related questions, and advising on scanning decisions for patients with complex or unclear devices ¹.

These roles are complementary, not interchangeable. The MRSO runs the program; the MRSE supplies the physics that makes its decisions defensible.

Key Technical Principles

The four MRI hazards

Every MRI safety control exists to manage one of four physical hazards, and understanding them is what separates rote rule-following from genuine safety judgment.

Static magnetic field (B0). The main field — commonly 1.5 T or 3 T — is always on and produces the projectile (missile) effect, in which ferromagnetic objects are accelerated toward the bore with lethal force. It also exerts translational force and rotational torque on ferromagnetic implants and can disrupt active devices. Because the magnet does not switch off with the building power, this hazard persists 24/7.
Radiofrequency field (B1). The transmit RF pulses deposit energy in tissue, quantified as the specific absorption rate (SAR). Excess deposition causes heating and burns, which can occur through conductive loops (crossed cables, skin-to-skin contact, looped leads) even at compliant whole-body SAR.
Switched gradient fields (dB/dt). Rapidly switching gradients can cause peripheral nerve stimulation (PNS) and generate intense acoustic noise — often exceeding 99 dB — which is why hearing protection is mandatory for patients and anyone remaining in the room.
Cryogens and quench. Superconducting magnets are cooled by liquid helium. A quench rapidly boils off that helium; if the vent system fails or is inadequate, the expanding gas can displace oxygen and cause asphyxiation, along with frostbite and overpressure risks. A functioning quench pipe and an oxygen monitor in Zone IV are essential.

Operating modes and SAR limits

The IEC 60601-2-33 standard caps RF energy deposition through three operating modes, and knowing where the scanner is operating is part of safe practice ³.

Normal Operating Mode — Whole-body SAR ≤ 2 W/kg (averaged over 6 minutes); head SAR ≤ 3.2 W/kg. Appropriate for routine clinical scanning of all patients.
First Level Controlled Operating Mode — Whole-body SAR up to 4 W/kg, which may cause physiologic stress such as heating or PNS, and therefore requires medical supervision and a deliberate decision to enter.
Second Level Controlled Operating Mode — Above First Level limits; restricted to approved research under an ethics/IRB protocol.

The same standard governs gradient output to keep dB/dt below the PNS threshold, and scanners are required to display and record SAR and dB/dt when operating in First Level mode ³.

Implant labeling: MR Safe, MR Conditional, MR Unsafe

Implant and device screening hinges on the ASTM F2503 labeling system, which sorts every item into one of three categories ⁴:

MR Safe (square icon) — Poses no known hazard in any MR environment because it is nonconducting, nonmetallic, and nonmagnetic.
MR Conditional (triangle icon) — Safe only under specified conditions: a maximum static field strength (e.g., 1.5 T vs 3 T), a maximum spatial gradient magnetic field, SAR or B1+rms limits, scan duration, and operating mode. Each condition must be verified against the actual scanner before the patient is scanned.
MR Unsafe (circle-slash icon) — A known hazard that must never enter Zone IV.

The practical difficulty is that "MR Conditional" is not a green light — it is a checklist. Confirming that a patient's specific implant model matches every listed condition for your specific scanner is precisely the kind of determination the MR Safety Expert exists to support.

Clinical Impact

What the 2024 ACR Manual changed

The 2024 update is less a rewrite than a sharpening: it tightens the human and procedural layers of the program where most real-world incidents originate ^{1, 2}. The most operationally relevant changes for a facility rebuilding its program are:

Updated MR personnel training levels and role-specific safety elements, clarifying what Level 1 and Level 2 personnel must know.
Revised staffing guidance for routine, emergency, and the growing practice of remote scanning, where the technologist may not be physically present.
A strengthened "full stop / final check" immediately before a patient or object enters Zone IV — a deliberate pause to re-verify screening.
Pocketless attire and equipment tethering to reduce the chance that loose ferromagnetic items reach the magnet.
A new appendix and risk-assessment pathway for managing patients with unclear or unlabeled implanted devices, where conditionality cannot be read off a label.
A site policy checklist that facilities can use as a template for their own written program.

MR Personnel: Level 1, Level 2, and Non-MR Personnel

Access to the restricted zones is governed by a personnel classification that determines who can be where, and who can supervise whom ¹.

Non-MR Personnel — Anyone not trained and not cleared (patients, visitors, untrained staff). They must be screened and escorted at all times and may never be alone in Zone III or IV.
Level 1 MR Personnel — Staff who have passed minimal safety education sufficient to protect themselves in the MR environment. They may move within Zone III but cannot assume responsibility for Non-MR Personnel.
Level 2 MR Personnel — Staff extensively trained in the broader range of MR safety issues, including RF burns, peripheral nerve stimulation, implants, and screening. Only Level 2 personnel can independently authorize and supervise access to Zones III and IV, and the MRSO is a Level 2 role.

This is why screening is not a clerical task. The person clearing a patient into the magnet room must understand the physics of why a particular implant, tattoo, or external device matters.

Practical Optimization Tips

A defensible MRI safety program can be built and audited against a short, concrete set of pillars. Facilities standing up or refreshing a program should work through each one.

1. Map and physically enforce the four zones

Walk the department and confirm the Zone II → Zone III boundary is a real, controlled door — not an open hallway. Verify access control (badge/key), MR signage, the illuminated "magnet on" indicator at Zone IV, and a functioning ferromagnetic detection system where used.

2. Name the three roles in writing

Designate an MRMD, an MRSO, and an MRSE by name in the written policy, with defined responsibilities. A program without a named MR Safety Expert has no clear owner for the physics decisions that screening depends on.

3. Build a screening process, not a form

Implement two-stage screening (Zone II intake plus a Zone IV "full stop / final check"), with a documented pathway for MR Conditional implants that records the scanner's field strength, spatial gradient, and SAR/B1+rms against the device's stated conditions. Add the 2024 manual's risk-assessment pathway for unlabeled or unclear implants.

4. Control burns and acoustic risk at the scanner

Standardize coil and cable placement, pad to prevent conductive loops and skin-to-skin contact, and enforce hearing protection for every patient and anyone remaining in Zone IV.

5. Verify quench safety

Confirm the quench vent is unobstructed and the oxygen monitor in Zone IV is calibrated and alarming correctly, and that staff are trained on quench and emergency egress procedures.

6. Train, drill, and log

Maintain Level 1 / Level 2 training records, run periodic safety drills (projectile response, quench, code in Zone IV), and capture near-misses. Closing these gaps early also reduces the broader compliance exposure discussed in Common Radiation Safety Violations and How to Avoid Them.

Regulatory Considerations

MRI is regulated differently from ionizing-radiation modalities: there is no MQSA-style federal quality mandate, so the binding requirements come primarily from accreditation and the Joint Commission rather than a state radiation-control program ^{5, 6}. Three layers matter.

CMS / MIPPA accreditation. Non-hospital suppliers that bill Medicare Part B for the technical component of advanced diagnostic imaging — MRI, CT, and nuclear medicine/PET — must be accredited by a CMS-approved body (ACR, IAC, The Joint Commission, or RadSite) ⁶. ACR MRI accreditation, in turn, requires an annual MRI equipment performance evaluation by a qualified medical physicist or MR scientist, which connects directly to the broader physics obligations summarized in our ACR Accreditation Physics Requirements overview.
Joint Commission NPG #13 and EC.02.04.03. As of January 1, 2026, the Joint Commission's National Performance Goals chapter replaced the National Patient Safety Goals, and NPG #13, "Protecting Patients and Providers in Imaging," now houses the MRI/CT/fluoroscopy safety expectations ⁵. The Joint Commission has stated that the new chapter consolidates existing requirements without introducing new ones — so the long-standing diagnostic-imaging expectations (ferromagnetic screening, restricted Zone III/IV access, hearing protection, incident reporting, and staff competency) continue to apply under a new label. Separately, the Joint Commission's diagnostic-imaging requirements (Standard EC.02.04.03, EP 23) call for an annual MRI equipment performance evaluation by a diagnostic medical physicist or MR scientist ⁸.
Device labeling and consensus standards. MRI scanners are cleared as medical devices against the IEC 60601-2-33 safety standard, and implant/device safety is communicated through ASTM F2503 labeling, supported by FDA guidance on testing and labeling devices for the MR environment ^{3, 4, 7}.

Because MRI uses non-ionizing fields, most state radiation-control programs that govern X-ray and radioactive material do not directly regulate MRI quality — which makes accreditation and a documented safety program, rather than a state inspection, the practical backbone of compliance.

Frequently Asked Questions (FAQs)

What is an MRI safety program?

An MRI safety program is the documented system of zones, trained personnel, screening procedures, and policies a facility uses to control the four core MRI hazards: the static magnetic field, RF heating, switched gradient fields, and cryogen quench. The current template is the 2024 ACR Manual on MR Safety, which assigns oversight to an MR Medical Director, an MR Safety Officer, and an MR Safety Expert ¹.

What are the four ACR MRI safety zones?

Zone I is freely accessible public space with no MR screening. Zone II is the transition area where patients are greeted and screened under supervision. Zone III is restricted because unscreened people or ferromagnetic objects can be seriously injured, and access is controlled by Level 2 MR Personnel. Zone IV is the scanner magnet room itself, the highest-risk area, always located within Zone III ¹.

Who can be an MR Safety Officer (MRSO)?

The MR Safety Officer is typically a Level 2 MR Personnel member — most often a senior MRI technologist — who has been extensively trained in MR safety, including burns, peripheral nerve stimulation, implant issues, and screening. The MRSO implements the day-to-day safety program under the MR Medical Director and is distinct from the MR Safety Expert, who provides the underlying physics expertise ¹.

What is the difference between MR Safe, MR Conditional, and MR Unsafe?

Under ASTM F2503, MR Safe items pose no known hazard in any MR environment because they are nonconducting, nonmetallic, and nonmagnetic. MR Conditional items are safe only under specified conditions such as field strength, spatial gradient, and SAR limits, which must each be verified. MR Unsafe items are known hazards and must never enter Zone IV ⁴.

Does the Joint Commission require an MRI safety program?

Yes. Joint Commission diagnostic-imaging requirements call for managing MRI safety risks — ferromagnetic screening, restricted Zone III/IV access, hearing protection, incident reporting, and staff competency. As of January 1, 2026, these requirements are consolidated under National Performance Goal #13, "Protecting Patients and Providers in Imaging," which replaced the National Patient Safety Goals chapter without adding new requirements ⁵.

Do I need a medical physicist for MRI safety?

Yes, in two ways. The 2024 ACR Manual identifies the MR Safety Expert — typically a medical physicist — as the technical authority who adjudicates implant conditionality, field strength, spatial gradient, and SAR questions. Separately, ACR accreditation and the Joint Commission's diagnostic-imaging standard EC.02.04.03 call for an annual MRI equipment performance evaluation by a qualified medical physicist or MR scientist ^{1, 6, 8}.

Key Takeaways

An MRI safety program controls four always-on hazards — static field (projectile and torque), RF heating (SAR/burns), switched gradients (PNS and acoustic noise), and cryogen quench — through engineered space, trained people, and written process ^{1, 3}.
The four-zone model uses access control to keep unscreened people and ferromagnetic objects away from the magnet; the Zone II → Zone III boundary is the most critical line in the department ¹.
Accountability is split across three roles: the MRMD (medical), the MRSO (operational, usually a Level 2 technologist), and the MRSE (technical, typically a medical physicist) ¹.
IEC 60601-2-33 caps whole-body SAR at 2 W/kg in Normal mode and 4 W/kg in First Level Controlled mode, and ASTM F2503 classifies devices as MR Safe, MR Conditional, or MR Unsafe ^{3, 4}.
The 2024 ACR Manual strengthened training levels, remote-scanning staffing, the "full stop / final check," pocketless attire, and a pathway for unclear/unlabeled implants ^{1, 2}.
Joint Commission NPG #13 (effective January 1, 2026) consolidated imaging safety expectations without adding new ones, while ACR accreditation and the Joint Commission's diagnostic-imaging standard EC.02.04.03 require an annual MRI performance evaluation by a medical physicist or MR scientist ^{5, 6, 8}.

How DRPS Can Help

Diagnostic Radiation Physics Services (DRPS) helps imaging programs build and defend MRI safety programs that satisfy both the 2024 ACR Manual and Joint Commission NPG #13. Our board-certified medical physicists (PhD, DABR, DABSNM) can serve as your MR Safety Expert (MRSE) — adjudicating MR Conditional implant conditions against your scanner's field strength, spatial gradient, and SAR/B1+rms — perform your annual MRI equipment performance evaluation, audit your four-zone access controls and screening SOPs, and prepare your team for ACR and Joint Commission survey. We serve facilities across Florida, Maryland, Virginia, Washington DC, California, and Nevada. Contact DRPS to scope an MRI safety assessment.

Conclusion

A strong MRI safety program is not a binder on a shelf — it is the daily discipline of zones, screening, and trained judgment that keeps an always-on magnet from harming the people around it. The static field, RF heating, switched gradients, and cryogen quench do not turn off, so the controls cannot either.

The 2024 ACR Manual on MR Safety gives facilities an up-to-date template, sharpening the human layers — training levels, remote-scanning staffing, the full stop before Zone IV, and a pathway for unclear implants — where most incidents actually begin. The Joint Commission's move to National Performance Goal #13 in 2026 reframes, but does not relax, the expectation that hospitals manage these risks. Programs that name their three roles, enforce their zones, screen rigorously, and engage a medical physicist as their MR Safety Expert will be the ones that pass survey and, more importantly, keep patients and staff safe.

References

American College of Radiology, Committee on MR Safety. ACR Manual on MR Safety. American College of Radiology; 2024. acr.org
Pedrosa I, Altman DA, Dillman JR, et al. American College of Radiology Manual on MR Safety: 2024 Update and Revisions. Radiology. 2025;315(1):e241405. doi:10.1148/radiol.241405. doi.org
International Electrotechnical Commission. IEC 60601-2-33: Medical Electrical Equipment — Part 2-33: Particular Requirements for the Basic Safety and Essential Performance of Magnetic Resonance Equipment for Medical Diagnosis. iec.ch
ASTM International. ASTM F2503: Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment. astm.org
The Joint Commission. National Performance Goals — NPG #13: Protecting Patients and Providers in Imaging. Effective January 1, 2026. jointcommission.org
Centers for Medicare & Medicaid Services. Advanced Diagnostic Imaging Accreditation (MIPPA, Section 135). Accessed June 4, 2026. cms.gov
U.S. Food and Drug Administration. Testing and Labeling Medical Devices for Safety in the Magnetic Resonance (MR) Environment: Guidance for Industry and Food and Drug Administration Staff. fda.gov
The Joint Commission. Diagnostic Imaging Requirements — Standard EC.02.04.03, EP 23: annual MRI equipment performance evaluation by a diagnostic medical physicist or MR scientist. Comprehensive Accreditation Manual. jointcommission.org