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Development of Unfolding Energy Spectrum with Clinical Linear Accelerator based on Transmission Data

물질투과율 측정정보 기반 의료용 선형가속기의 에너지스펙트럼 유도기술 개발

  • Choi, Hyun Joon (Department of Radiation Convergence Engineering, Yonsei University) ;
  • Park, Hyo Jun (Department of Radiation Convergence Engineering, Yonsei University) ;
  • Yoo, Do Hyeon (Department of Radiation Convergence Engineering, Yonsei University) ;
  • Kim, Byoung-Chul (Center for Ionizing Radiation, Korea Research Institute of Standards and Science) ;
  • Yi, Chul-Young (Center for Ionizing Radiation, Korea Research Institute of Standards and Science) ;
  • Min, Chul Hee (Department of Radiation Convergence Engineering, Yonsei University)
  • 최현준 (연세대학교 방사선융합공학과) ;
  • 박효준 (연세대학교 방사선융합공학과) ;
  • 유도현 (연세대학교 방사선융합공학과) ;
  • 김병철 (한국표준과학연구원 방사선표준센터) ;
  • 이철영 (한국표준과학연구원 방사선표준센터) ;
  • 민철희 (연세대학교 방사선융합공학과)
  • Received : 2015.12.21
  • Accepted : 2016.03.15
  • Published : 2016.03.31

Abstract

Background: For the accurate dose assessment in radiation therapy, energy spectrum of the photon beam generated from the linac head is essential. The aim of this study is to develop the technique to accurately unfolding the energy spectrum with the transmission analysis method. Materials and Methods: Clinical linear accelerator and Monet Carlo method was employed to evaluate the transmission signals according to the thickness of the observer material, and then the response function of the ion chamber response was determined with the mono energy beam. Finally the energy spectrum was unfolded with HEPROW program. Elekta Synergy Flatform and Geant4 tool kits was used in this study. Results and Discussion: In the comparison between calculated and measured transmission signals using aluminum alloy as an attenuator, root mean squared error was 0.43%. In the comparison between unfolded spectrum using HEPROW program and calculated spectrum using Geant4, the difference of peak and mean energy were 0.066 and 0.03 MeV, respectively. However, for the accurate prediction of the energy spectrum, additional experiment with various type of material and improvement of the unfolding program is required. Conclusion: In this research, it is demonstrated that unfolding spectra technique could be used in megavoltage photon beam with aluminum alloy and HEPROW program.

Acknowledgement

Supported by : 한국연구재단, 한국표준과학연구원

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