New Physics: Sae Mulli (새물리)

Korean Physical Society (한국물리학회)
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Dosimetric Characteristics of a Polymer Gel for a 45 MeV Proton Beam

45 MeV 양성자 빔을 이용한 중합체 겔 선량계의 특성 평가

  • Bong, Jihye (Department of Medical Physics, Kyonggi University, Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Kim, Kumbae (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Yang, Tae-Keun (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Ko, Inok (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Park, Jiae (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Min, Kyeong (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Jung, Haijo (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Ji, Younghoon (Research Institute of Radiological & Medical Science, Korea Institute of Radiological & Medical Sciences) ;
  • Kwon, Soo-Il (Department of Medical Physics, Kyonggi University)
  • 봉지혜 (경기대학교 대학원 의학물리학과, 한국원자력 의학원 방사선 의학 연구소) ;
  • 김금배 (한국원자력 의학원 방사선 의학 연구소) ;
  • 양태건 (한국원자력 의학원 방사선 의학 연구소) ;
  • 고인옥 (한국원자력 의학원 방사선 의학 연구소) ;
  • 박지애 (한국원자력 의학원 방사선 의학 연구소) ;
  • 김경민 (한국원자력 의학원 방사선 의학 연구소) ;
  • 정해조 (한국원자력 의학원 방사선 의학 연구소) ;
  • 지영훈 (한국원자력 의학원 방사선 의학 연구소) ;
  • 권수일 (경기대학교 대학원 의학물리학과)
  • Published : 2012.01.31
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Abstract

A normoxic polymer gel dosimeter was developed to measure the dosimetric characteristics of a 45 MeV proton beam. The gel dosimeter was synthesized using gelatin, methacrylic acid (MAA), hydroquinon (HQ), tetrakis (THPC) and Distilled water (HPLC) and was poured into an ABS container. The 45 MeV proton beam of the MC-50 cyclotron accelerator was used for testing the gel dosimeter, and using a collimator, we exposed the gel dosimeter at a diameter of 12 mm and a beam current of 2 nA. For the comparison with the gel dosimeter, 50 films of EBT2 were seriated and exposed to 5 nA for 5 sec. The relaxation rate $(R_2)$ of the gel dosimeter exposed to the beam was obtained using 3.0T MRI and its dose was analyzed. In the dosimetric range of 0 ~ 15.5 Gy, the correlation coefficient was analyzed. The bragg peak of the proton beam based on the dosimetric changes in the 3.9 ~ 5.3 Gy dosimetric range was found at WED 12.39 mm. The possibility for using the gel dosimeter with films for the dosimetric measurement of a proton beam was confirmed.

정상산소 중합체 겔 선량계를 제작하여 45 MeV 양성자 빔에 대한 선량 특성을 측정하였다. 겔 선량계는 젤라틴(Gelatin), 메타크릴산(MAA), 히드로퀴논(HQ), 테트라키스(THPC), 증류수(HPLC)를 이용하여 합성하고 ABS용기에 넣었다. 겔 선량계는 MC-50 사이클로트론 가속기의 45 MeV 양성자 빔을 사용하였으며 콜리메이터를 이용하여 지름 12 mm, 빔전류 2 nA 로 조사하였다. 겔 선량계와의 비교를 위해서 $Gafchromic^{(R)}$ 필름 50장을 연속 배열하여 5 nA로 5 초 동안 조사시켰다. 빔이 조사된 겔 선량계는 3.0 T MRI를 이용하여 횡이완률 $R_2$ 값을 얻어 선량을 분석하였다. 0 ~ 15.5 Gy 선량범위에서 선형상관계수를 구하였다. 3.9 ~ 5.3 Gy 선량 영역에서 선량변화에 따른 양성자 빔의 브래그 피이크는 WED 12.39 mm 에서 나타났다. 양성자 빔의 선량 측정에 겔 선량계가 필름과 함께 선량분포를 확인하는데 유용하게 사용될 수 있는 가능성을 확인하였다.

Keywords

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