Characterization of Radiofrequency (RF) Coil Heating in Magnetic Resonance Imaging Systems

Abstract

This NEMA Standards publication describes measurement procedures for determining the maximum surface temperature of RF coils (integrated transmit, integrated receive, detachable receive, detachable transmit/receive, specialty coils), as specified in IEC 60601-1, due to absorbed RF power under worstcase normal use conditions when in a volume transmit coil.

Non-volume transmit-receive array coils, nonvolume transmit array coils, and detachable coils with their own RF screen/shield are out of scope for this edition and may be considered in a future revision.

Additional thoughts regarding the applicability of the Standard to out of scope coils are found in appendix B.

This Standard provides recommendations for coils configured for intended use, consideration for systems operating in a B1 shimmed configuration, multi-frequency coils, and the unplugged condition.

The methods described may be applicable to other coil types, with appropriate modifications.

Gradient induced heating is out of scope.

Certain large surface area RF coil designs may experience additional incremental heating due to intensive gradient activity.

Users of this Standard will identify and adapt appropriate methods as necessary.

Consult with local regulations and IRBs when applying these methods to research, prototype, or investigational device coils.

All uses of “Note:” are to be interpreted as informative, not normative text in this Standard.