Journal of the Korean Society of Radiology (한국방사선학회논문지)

The Korean Society of Radiology (한국방사선학회)
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Analysis of the Photon Beam Characteristics by Medical Linear Accelerator According to Various Target Materials using MCNP-code

MCNP-code를 이용한 의료용 선형가속기의 타깃 재질에 따른 광자선 특성 분석

  • Lee, Dong-Yeon (Department of Radiation Oncology, Dongnam Inst. of Radiological & Medical Science) ;
  • Park, Eun-Tae (Department of Radiation Oncology, Busan Paik Hospital, Inje University) ;
  • Kim, Jung-Hoon (Department of Radiological Science, College of Health Sciences, Catholic University of Pusan)
  • 이동연 (동남권원자력의학원 방사선종양학과) ;
  • 박은태 (인제대학교 부산백병원 방사선종양학과) ;
  • 김정훈 (부산가톨릭대학교 보건과학대학 방사선학과)
  • Received : 2017.05.30
  • Accepted : 2017.08.31
  • Published : 2017.08.31
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Abstract

This study purpose is propose the basic data for selecting the optimal target material by analyzing the photon characteristics of various materials which was located in the head of medical linear accelerator. In this study, energy spectrum of 6, 15 MV photon beams were compared and analyzed for 13 target materials using MCNPX of Monte Carlo method. The mean energy for the 6 MV energy spectrum was 1.69 ~ 1.84 MeV and that for the 15 MV was 3.38 ~ 3.56 MeV, according to the target material. The flux for the 6 MV energy spectrum was $1.64{\times}10^{-5}{\sim}1.80{\times}10^{-5}{\sharp}/cm^2/e$ and that for the 15 MV was $1.76{\times}10^{-4}{\sim}1.85{\times}10^{-4}{\sharp}/cm^2/e$. The analysis shows that the average energy and flux increase with higher atomic number of the target material. Based on this study, it is possible to present the basic data about the physical characteristics of the photon, and it will be possible to select the target later considering economic, efficiency and physical aspect.

의료용 선형가속장치의 두부 구성요소 중 광자 발생의 원인이 되는 타깃에 대한 연구로써, 타깃의 재질에 따른 광자를 분석하여 타깃 재질 별 발생하는 광자특성에 대한 기초자료를 제시하고자 한다. 본 연구에서는 몬테카를로 방식을 바탕으로 한 MCNPX를 사용하여 타깃 재질에 따른 6, 15 MV의 광자 특성을 비교분석하였다. 타깃 재질 별 평균에너지는 6 MV에서 1.69 ~ 1.84 MeV, 15 MV에서는 3.38 ~ 3.56 MeV로 분석되었다. Flux는 6 MV에서 $1.64{\times}10^{-5}{\sim}1.80{\times}10^{-5}{\sharp}/cm^2/e$, 15 MV는 $1.76{\times}10^{-4}{\sim}1.85{\times}10^{-4}{\sharp}/cm^2/e$로 계산되었다. 결과를 분석하면, 타깃 재질이 고원자번호일수록 평균에너지와 Flux가 증가하는 것으로 평가다. 본 연구를 바탕으로 광자의 물리적 특성에 대한 기초적인 자료를 제시할 수 있었으며, 추후 타깃 선정 시 경제성, 효율성은 물론 물리적 측면을 고려할 수 있어 적절한 선택을 할 수 있을 것으로 판단된다.

Keywords

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