The Effects of the Statistical Uncertainties in Monte Carlo Photon Dose Calculation for the Radiation Therapy

방사선 치료를 위한 몬테칼로 광자선 선량계산 시 통계적 불확실성 영향 평가

  • Cheong, Kwang-Ho (Dept. of Biomedical Engineering, The Catholic University of Korea) ;
  • Suh, Tae-Suk (Dept. of Biomedical Engineering, The Catholic University of Korea) ;
  • Cho, Byung-Chul (Dept. of Radiation Oncology, Hallym University Sacred Heart Hospital)
  • 정광호 (가톨릭의대 의공학교실) ;
  • 서태석 (가톨릭의대 의공학교실) ;
  • 조병철 (한림성심병원 방사선종양학과)
  • Published : 2004.06.30

Abstract

The Monte Carlo simulation requires very much time to obtain a result of acceptable accuracy. Therefore we should know the optimum number of history not to sacrifice time as well as the accuracy. In this study, we have investigated the effects of statistical uncertainties of the photon dose calculation. BEAMnrc and DOSXYZnrc systems were used for the Monte Carlo dose calculation and the case of mediastinum was simulated. The several dose calculation result from various number of histories had been obtained and analyzed using the criteria of isodose curve comparison, dose volume histogram comparison(DVH) and root mean-square differences(RMSD). Statistical uncertainties were observed most evidently in isodose curve comparison and RMSD while DVHs were less sensitive. The acceptable uncertainties $(\bar{{\Delta}D})$ of the Monte Carlo photon dose calculation for the radiation therapy were estimated within total 9% error or 1% error for over than $D_{max}/2$ voxels or voxels at maximum dose.

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