Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
권호 표지

Evaluation of Photoneutron Energy Distribution in the Radiotherapy Room

방사선치료실 내의 광중성자 에너지 분포 평가

  • Park, Euntae (Dept. of Radiologic Science, Graduate School of Catholic University of Pusan) ;
  • Ko, Seongjin (Dept. of Radiologic Science, College of Health Sciences, Catholic University of Pusan) ;
  • Kim, Junghoon (Dept. of Radiologic Science, College of Health Sciences, Catholic University of Pusan) ;
  • Kang, Sesik (Dept. of Radiologic Science, College of Health Sciences, Catholic University of Pusan)
  • 박은태 (부산가톨릭대학교 대학원 방사선학과) ;
  • 고성진 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 김정훈 (부산가톨릭대학교 보건과학대학 방사선학과) ;
  • 강세식 (부산가톨릭대학교 보건과학대학 방사선학과)
  • Received : 2014.07.24
  • Accepted : 2014.09.17
  • Published : 2014.09.30
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Abstract

Medical linear accelerator is widely used in radiation treatment field, and high energy photons, above 10 MV nominal accelerator voltage, are commonly utilized for the radiation treatment. However, these high energy photons lead the photo-nuclear reaction and the generation of photo-neutrons are accompanied. Thus, these problematic factors are issued in the view of radiation protection. Therefore, linear accelerator and radiation treatment room are simulated from MCNPX program in this study. The measurement points of interest are selected and analyzed, and the resulting effects derived from the properties of photo-neutron are evaluated. Therefore, we realized that the number of generating photo-neutrons was decreased by depending on the distance from the source. No matter what the nominal energy is set, the rates thermal neutrons to fast neutrons are marginal. It is founded that the amount of the thermal neutrons were decreased by depending on the distance from the source.

의료용의 선형가속장치는 방사선치료에 있어서 그 활용도가 가장 높으며, 최근에는 10MV 이상의 고에너지 광자선을 이용한 치료가 보편화되고 있다. 그러나 광핵반응에 의한 광중성자가 생성됨으로써 방사선 방호측면에서 많은 문제를 야기 시키고 있다. 이에 본 연구는 MCNPX 프로그램을 이용하여 치료실 내의 위치별 중성자의 특성을 분석하였다. 그 결과, 광중성자의 생성 개수도 선원 중심점을 기준으로 거리가 멀어질수록 감소됨을 알 수 있었다. 그리고 10MV에서 20MV로 에너지가 높아짐에 따른 열중성자와 속중성자의 비율은 큰 차이가 없었지만, 선원 중심점으로부터 거리가 이격될수록 열중성자의 비율이 높아지는 현상을 확인할 수 있었다.

Keywords

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