TY - JOUR
T1 - Use of a radio frequency shield during 1.5 and 3.0 tesla magnetic resonance imaging
T2 - Experimental evaluation
AU - Favazza, Christopher P.
AU - King, Deirdre M.
AU - Edmonson, Heidi A.
AU - Felmlee, Joel P.
AU - Rossman, Phillip J.
AU - Hangiandreou, Nicholas J.
AU - Watson, Robert E.
AU - Gorny, Krzysztof R.
N1 - Publisher Copyright:
© 2014 Favazza et al.
PY - 2014/10/29
Y1 - 2014/10/29
N2 - Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient’s body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices.
AB - Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient’s body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices.
KW - Magnetic resonance imaging
KW - Radiofrequency attenuation
KW - Radiofrequency shield
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U2 - 10.2147/MDER.S68657
DO - 10.2147/MDER.S68657
M3 - Article
AN - SCOPUS:84908305947
SN - 1179-1470
VL - 7
SP - 363
EP - 370
JO - Medical Devices: Evidence and Research
JF - Medical Devices: Evidence and Research
ER -