How Thin Can You Go? Performance of Thin Copper and Aluminum RF Coil Conductors

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  • This is the peer reviewed version of the following article: Magn Reson Med. Early View, which has been published in final form at This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
    To evaluate the impact of emerging conductor technology on radio-frequency (RF) coils. Performance and resulting image quality of thin or alternate conductors (e.g., aluminum instead of copper) and thicknesses (9–600μm) are compared in terms of signal-to-noise ratio (SNR).
    Eight prototype RF coils (15 cm × 15 cm square loops) were constructed and bench tested to measure quality factor (Q). The coils used 6 mm wide conducting strips of either copper or aluminum of a few different thicknesses (copper: 17, 32, 35, 127, 600 μm; aluminum: 9, 13, 20, 127 μm) on acetate projector sheets for backing. Corresponding image SNR was measured at 0.48 T (20.56 MHz).
    The coils spanned a range of unloaded quality factors from 89 to 390 and a five-fold range of losses. The image SNRs were consistent with the coils’ bench-measured efficiencies (0.33 to 0.73). Thin aluminum conductors (9 μm) led to the highest reduction in SNR (65% that of 127 μm copper). Thin copper (<32 μm) conductors lead to a much smaller decrease in SNR (approximately 10%) compared to 127 μm copper. No performance difference was observed between 127 μm thick copper and aluminum. The much thicker 600 μm copper bars only yield a 5% improvement in SNR.
    Even at 0.48 T copper RF coil conductors much thinner than those in conventional construction can be used while maintaining SNR greater than 50% that of thick copper. These emerging coil conductor technologies enable RF coil functionality that cannot be achieved otherwise.

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    Attribution-NonCommercial-NoDerivatives 4.0 International