Journal of the Korean Society of Radiology (한국방사선학회논문지)

The Korean Society of Radiology (한국방사선학회)
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A Study on Photon Spectrum in Medical Linear Accelerator Based on MCNPX

MCNPX를 이용한 의료용 선형가속장치의 광자 스펙트럼에 관한 연구

  • Park, Euntae (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan) ;
  • Lee, Dongyeon (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan) ;
  • Ko, Seongjin (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan) ;
  • Kim, Junghoon (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan) ;
  • Kang, Sesik (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan)
  • 박은태 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 이동연 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 고성진 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 김정훈 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 강세식 (부산가톨릭대학교 보건과학대학 방사선학과)
  • Received : 2014.05.26
  • Accepted : 2014.08.25
  • Published : 2014.08.30
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Abstract

Medical linear accelerator is used for radiotherapy since it was developed in 1952, the utilization rate is further increased. It is used high energy radiotherapy using the energy of the photon of 6 MeV or more is universal at present, but the creation of the neutron by photonuclear reaction cause a problem that is radiation exposure of patients and operators. Therefore, in this study, to analyze the spectrum of the photon beam of 6 to 24 MV that occurred in the medical linear accelerator using the Monte Carlo code MCNPX, the number of photons of 7.41 MeV or more, which is a neutron production threshold energy of tungsten and average energy. The result of 24 MV in the beginning and the 8 MV was 0.59% of the total number of detected photons and it was founded that the number of photons are increased which are possible to cause the photonuclear reaction.

의료용 선형가속장치는 1952년에 개발된 이후 방사선 치료에 사용되어 왔으며 그 활용도가 더욱 증가하고 있다. 현재는 6 MeV 이상의 광자 에너지를 사용하는 고 에너지 방사선치료가 보편화되어 사용되고 있으나, 광핵반응에 의한 중성자의 생성으로 환자 및 술자에 대한 피폭이 문제가 되고 있다. 이에 본 연구에서는 MCNPX를 사용하여 의료용 선형가속장치에서 발생되는 6~24 MV 광자선의 스펙트럼을 분석하고, 평균에너지 및 텅스텐의 중성자 생성 임계에너지인 7.41 MeV 이상의 광자 개수를 평가하였다. 그 결과 8 MV를 시작으로 24 MV에서는 전체 검출 광자 수에 비해 0.59%의 비율로서 광핵 반응을 일으킬 수 있는 광자수가 증가함을 알 수 있었다.

Keywords

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