✦ LIBER ✦

Radiofrequency shielding of surface coils at 4.0 t

✍ Scribed by Kenneth C. Ong; Han Wen; A. Scott Chesnick; Stefan Duewell; Farouc A. Jaffer; Robert S. Balaban

Publisher: John Wiley and Sons
Year: 1995
Tongue: English
Weight: 512 KB
Volume: 5
Category: Article
ISSN: 1053-1807
DOI: 10.1002/jmri.1880050626

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

Because radiation loss associated with a radiofrequency (RF) coil increases as roughly the fourth power of the frequency, this loss mechanism may become important in high‐field studies above 2.0 T. In this study, the contribution of radiation losses at 4.0 T were determined in a rectangular surface coil using an RF shield to modify the radiation losses. The effect of this shield was determined on coil Q, B~1~ distribution, and signal to noise as a function of distance between the coil and the shield. Phantoms and human tissue were evaluated to characterize the loss mechanisms. The results demonstrate a large radiation loss in the unshielded surface coil. However, the radiation losses in vivo were not dominant owing to a large inductive loss occurring from dielectric currents in the body at 170 MHz.

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