dB/dt Evaluation in MRI Sites: Is ICNIRP Threshold Limit (for Workers) Exceeded?

Area of Science:

• Medical Physics
• Occupational Health and Safety
• Electromagnetism

Background:

• Directive 2013/35/EU sets exposure standards for magnetic fields.
• ICNIRP guidelines, based on induced electric fields, are complex to measure.
• Theoretical models are used due to measurement complexities.

Purpose of the Study:

• To experimentally evaluate magnetic field exposures for MRI workers.
• To assess compliance with regulatory limits using measured dB/dt values.
• To investigate the implications of ultra-high field MRI on worker safety.

Main Methods:

• Measurements conducted on 0.35 T, 1.5 T, and 3.0 T MRI systems.
• Pocket magnetic dosimeters used during routine, emergency, and maintenance conditions.
• Data processed to compute dB/dt curves and apply weighted peak approach for compliance.

Main Results:

• Reference levels (RL) were consistently exceeded on the 3.0 T scanner.
• RL was sometimes exceeded on 1.5 T scanners.
• dB/dt peak values indicate potential overexposure risks.

Conclusions:

• Ultra-high field MRI scanners pose a significant risk of exceeding magnetic field exposure limits.
• Behavioral rules may offer a more practical safety approach than strict numerical limits.
• Further research into safety protocols for advanced MRI systems is warranted.