TY - GEN
T1 - Effect of an active noise control system on acoustical noise during magnetic resonance imaging diagnosis
AU - Nakayama, Shohei
AU - Muto, Kenji
AU - Kazuo, Yagi
AU - Chen, Guoyue
PY - 2013/1/1
Y1 - 2013/1/1
N2 - A magnetic resonance imaging (MRI) equipment generates loud sounds during its operation. The sound pressure level depends on the imaging sequences but is generally around 100 dB. This makes patients uncomfortable, and temporary hearing loss is possible if ear protection to decrease the sound pressure level by 20 dB is not used. This situation is so discomforting to the patient that in some cases MRI diagnosis and treatment may be refused. We studied ear protectors with an active noise control (ANC) system. Traditional protectors can decrease sound pressure level for high frequencies, but ANC systems can control low-frequency sounds as well. This study considers improvements to the acoustical environment when using ANC systems for MRI patients. The ANC system we developed is a feedforward system because MRI acoustical noise is unsteady and pulsed. The system uses nonmagnetic devices, ear protectors, and optical microphones because MRI rooms are highly magnetic environments. A computer simulation showed that the transition of the level of MRI acoustical noise was controlled by the ANC system during a diagnosis. As a result, the system reduced the MRI acoustical noise from 110 dB to 70 dB and was capable of changing the imaging sequences during MRI operation. Copyright
AB - A magnetic resonance imaging (MRI) equipment generates loud sounds during its operation. The sound pressure level depends on the imaging sequences but is generally around 100 dB. This makes patients uncomfortable, and temporary hearing loss is possible if ear protection to decrease the sound pressure level by 20 dB is not used. This situation is so discomforting to the patient that in some cases MRI diagnosis and treatment may be refused. We studied ear protectors with an active noise control (ANC) system. Traditional protectors can decrease sound pressure level for high frequencies, but ANC systems can control low-frequency sounds as well. This study considers improvements to the acoustical environment when using ANC systems for MRI patients. The ANC system we developed is a feedforward system because MRI acoustical noise is unsteady and pulsed. The system uses nonmagnetic devices, ear protectors, and optical microphones because MRI rooms are highly magnetic environments. A computer simulation showed that the transition of the level of MRI acoustical noise was controlled by the ANC system during a diagnosis. As a result, the system reduced the MRI acoustical noise from 110 dB to 70 dB and was capable of changing the imaging sequences during MRI operation. Copyright
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M3 - Conference contribution
AN - SCOPUS:84904506646
SN - 9781632662675
T3 - 42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life
SP - 3603
EP - 3608
BT - 42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013
PB - OAL-Osterreichischer Arbeitsring fur Larmbekampfung
T2 - 42nd International Congress and Exposition on Noise Control Engineering 2013: Noise Control for Quality of Life, INTER-NOISE 2013
Y2 - 15 September 2013 through 18 September 2013
ER -