Metal Objects Show Dangerous Attraction in MRI Scanners
A new study quantifies how common items can act as projectiles in high-intensity magnetic fields.
Updated on Oct. 22, 2026 in Materials Science
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The December 2023 CHRISTMAS study published in The BMJ analyzed how common items behave when exposed to 3-tesla MRI magnets. Researchers demonstrated that everyday objects like cutlery and 10-pence coins can become dangerous projectiles by piercing ballistic gel.
Why it matters
The findings underscore persistent safety risks in radiology environments, where uncontrolled metal objects can be pulled into high-intensity magnetic fields. The study clarifies the physical behavior of common items that the FDA continues to track in hundreds of annual adverse event reports.
The study utilized a 3-tesla MRI magnet to test object attraction, finding that a knife achieved a maximum penetration depth of 5.5 centimeters into 10% concentration ballistic gel. Unlike cutlery, specific coins like 20p, 50p, and £2 pieces showed no measurable magnetic attraction.
The players
The BMJ
A peer-reviewed medical journal that publishes original research across clinical and public health disciplines.
FDA
The federal agency responsible for regulating medical devices and collecting data on adverse events in healthcare settings.
The details
Researchers used an electromagnetic launch funnel—a custom assembly of polystyrene foam and acrylic tubes—to slide objects toward the magnet at controlled entry points. They defined the SANTA value, or Static Attraction Non-magnetic Threshold Assessment, as the point where the magnetic pull overcomes surface friction to initiate acceleration. The ballistic gel, a 10% gelatin mixture, acted as a proxy for human tissue to measure potential trauma depth.
Timeline
2001: A metal oxygen tank caused a fatal MRI accident.
2008: Joint Commission safety alert regarding projectile incidents was issued.
December 2023: The CHRISTMAS study was published in The BMJ.
July 2025: A man died following an MRI projectile accident.
The Tech Race
This study updates the risk profile for clinical environments following the 2008 Joint Commission safety alert. It provides the necessary physical benchmarks to refine current safety screening protocols in hospital radiology departments.
Medical facilities rely on these findings to improve screening procedures for staff and patients entering 3-tesla scanner zones. Patients and staff must maintain strict control of personal items, as the study shows that everyday objects can cause significant damage or physical harm when pulled by the magnet.
The takeaway
The study demonstrates that seemingly inert items like cutlery pose a real risk of penetrating human tissue in the presence of strong magnets. Future safety efforts should monitor the frequency of projectile accidents reported to the FDA to see if awareness campaigns reduce these incidents.
Further reading
Explore the latest developments in safety and testing at Materials Science.
Source note: This article includes information reported by Medical Daily.
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