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Monte Carlo Simulation for the Measurement of Entrance Skin Dose on Newborn and Infants

영·유아의 입사피부선량 측정을 위한 몬테카를로 시뮬레이션

  • Received : 2012.04.02
  • Accepted : 2012.05.03
  • Published : 2012.06.28

Abstract

Radiation dose estimation on the newborn and infants during radiation examinations, unlike for the adults, is not actively being progressed. Therefore, as an index to present exposure dose during radiation examinations on newborn and infants, entrance skin dose was measured, and the result was compared with results of monte carlo simulation to raise reproducibility of entrance skin dose measurement, and it was proved that various geometry implementation was possible. The resulting values through monte carlo simulation was estimated using normalization factors for entrance skin dose to calibrate radiation dose and then normalized to a unit X ray radiation field size. Average entrance skin dose per one time exposure was $78.41{\mu}Gy$ and the percentage error between measurement by dosimeter and by monte carlo simulation was found to be -4.77%. Entrance skin dose assessment by monte carlo simulation provides possible alternative method in difficult entrance skin dose estimation for the newborn and infants who visit hospital for actual diagnosis.

성인과 달리 영 유아에게 행해지는 방사선 검사 시 투여되는 방사선량의 평가는 활발하게 이루어지지 않고 있다. 따라서 영 유아의 방사선 검사 시 피폭되는 정도를 나타내는 지표로서 입사피부선량을 측정하고 Geant4를 이용한 몬테카를로 시뮬레이션을 통한 결과값을 비교하여 입사피부선량 측정의 재현성을 높이고 다양한 지오메트리 구현의 가능성을 증명하였다. 몬테카를로 시뮬레이션 결과값은 입사피부선량을 선량보정을 위한 정규인자를 통해 추정하였고 단위 X선 조사영역크기로 표준화한 결과 영 유아에게 있어 일회의 방사선 촬영 당 평균 입사피부선량은 $78.41{\mu}Gy$ 였으며 선량계를 통한 측정값과 몬테카를로 시뮬레이션값의 백분율 오차는 최대 -4.77%로 나타났다. 몬테카를로 시뮬레이션을 통한 입사피부선량 평가 방법은 의료기관에서 실제 진단을 위해 내원한 환아를 대상으로 한 입사피부선량 평가의 어려움을 대체할만한 수단으로서의 가능성을 보여준다.

Keywords

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