The Journal of the Korea Contents Association (한국콘텐츠학회논문지)

The Korea Contents Association (한국콘텐츠학회)
권호 표지
DOI QR코드

DOI QR Code

Analysis of Specific Absorption Rate in Magnetic Resonance Imaging

자기공명영상장치에서 전자파흡수율 분석

  • 한재복 (전남대학교 전자컴퓨터공학과) ;
  • 홍성훈 (전남대학교 전자컴퓨터공학과) ;
  • 최남길 (동신대학교 방사선학과) ;
  • 성호진 (조선대학교 원자력공학과)
  • Received : 2013.01.02
  • Accepted : 2013.02.01
  • Published : 2013.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, we measured specific absorption rate (SAR) using characteristic variables such as flip angle, repetition time (TR) and echo time (TE) at magnetic resonance imaging. The subject was applied to same scan technique from body weight 10 kg to 90 kg, were measured for the average SAR and the peak SAR values according to the change of parameter. SAR with different body weight levels was not seen a significant change at TE but it increased in the larger flip angle and the shorter TR. SAR value was within the limits of human head acceptable standard and SNR in segmental body weights was not proportional to the increase of body weights. In conclusion, this study can be helpful for diagnosis by using appropriate parameters which obtained the various contrast and SNR.

본 연구는 자기공명영상장치의 특성변수인 숙임각(flip angle), 반복시간(repetition time, TR), 에코시간(echo time, TE)을 사용하여 전자파흡수율(specific absorption rate, SAR)을 알아보고자 하였다. 연구대상은 체중 10 kg부터 90 kg까지를 대상으로 하여 동일한 검사기법을 적용하였고, 매개변수의 변화에 따른 평균 SAR 및 peak SAR 값을 측정하였다. 체중에 따른 SAR는 TE에서 변화는 없지만 숙임각이 커지고 TR이 짧을수록 증가하였다. SAR 값은 두부 허용 기준치 범위에 포함이 되었고 분절별 체중에 따른 영상의 신호 대 잡음비(signal to noise ratio, SNR)는 체중이 증가함에 따라 SNR은 증가하지는 않았다. 본 결과를 바탕으로 적절한 특성변수를 사용하여 다양한 대조도와 SNR을 얻어 진단의 가치를 높일 수 있을 것이다.

Keywords

References

  1. S. J. Go, "Metal Artifact Caused by Magnetic Field Strength and Sequence on T1WI-MRI," J. of Contents Association, Vol.10, No.9, pp.302-308, 2010. https://doi.org/10.5392/JKCA.2010.10.9.302
  2. L. S. Babiars, J. M. Romero, E. K. Murphy, B. Brobeck, P. W. Schaefer, and R. G. Gonzlez, "Contrast enhanced MR angiography is not more accurate than unenhanced 2D time-of-flight MR angiography for determining internal cartoid artery stenosis," AJNR Am J Neuroradial, Vol.30, pp.760-768, 2009.
  3. J. Alvarez Linera, J. Benito-Len, J. EscribanoJ, J. Campollo, and R. Gesto, "Prospective evaluation of cartoid artery stenosis: elliptic centric contrast-enhanced MR angiography and spiral CT angiography compared with digital subtraction angiography," AJNR Am J Neuroradial, Vol.24, pp.1012-1019, 2003.
  4. K. S. Lee, H. Sim, J. H. Moon, and J. C. Oh, "Implementation about measurement of the head SAR and variable parameter according to operation control mode in brain MR study with 1.5Tesla," The Transactions of the Korean Institute of Electrical Engineers, Vol.4, pp58-60, 2007.
  5. A. K. Lee, H. D. Choi, and J. S. Kim, "Analysis of SAR in a Human Head for a Celluar Phone," Journal of Electromagnetic Engineering and Science, Vol.9, No.6, pp.776-787, 1998.
  6. American National Standard-Safety levels with respect to human exposure to radio frequency electromagnetic fields, 3 kHz to 300 GHz, ANSI/IEEE C95.1-1992.
  7. H. Bosmans, G. Marchal, G. Luktio, Time-of -flight MR angiography of the brain: comparison of acquistion techniques in healthy volunteers," Am J Roentgenol, Vo1.164, pp.161-167, 1995.
  8. F. R. Korosec and C. A. Mistretta "MR angiography: basic principles and theory," Magn Reson Imaging Clin N am, Vol.6, pp.223-256, 1998.
  9. FCC, OET Bulletin 65, Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic fields, Edition 97-01, released August 25, 1997.
  10. CENELEC, Considerations for Human Exposure to EMFs from Mobile Telecommunication Equipment (MTE) in the Frequency Range 30 MHz - 6 GHz, European Committee for Electrotechnical Standardisation SECRETARIAT SE 211/B WAMTE Fec. 1997.
  11. J. Hennig and K. Scheffler, "Hyperechoes in RARE(TSE, FSE)-sequences," Pro. Intl. Soc. Mag Reson Med, Nol.9. pp.1769, 2001.