의학물리학

  • [Phys Med Biol.] Development of Integrated Prompt Gamma Imaging and Positron Emission Tomography System for in Vivo 3-D Dose Verification: A Monte Carlo Study 생체 내 3차원 선량 검증을 위한 통합 즉발 감마 영상 및 양전자 방출 단층 촬영 시스템 개발 연구

    연세대 / 최현준, 민철희*

  • 출처
    Phys Med Biol.
  • 등재일
    2020 May 22
  • 저널이슈번호
    65(10):105005. doi: 10.1088/1361-6560/ab857c.
  • 내용

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    Abstract
    An accurate knowledge of in vivo proton dose distribution is key to fully utilizing the potential advantages of proton therapy. Two representative indirect methods for in vivo range verification, namely, prompt gamma (PG) imaging and positron emission tomography (PET), are available. This study proposes a PG-PET system that combines the advantages of these two methods and presents detector geometry and background reduction techniques optimized for the PG-PET system. The characteristics of the secondary radiations emitted by a water phantom by interaction with a 150 MeV proton beam were analysed using Geant4.10.00, and the 2-D PG distributions were obtained and assessed for different detector geometries. In addition, the energy window (EW), depth-of-interaction (DOI), and time-of-flight (TOF) techniques are proposed as the background reduction techniques. To evaluate the performance of the PG-PET system, the 3-D dose distribution in the water phantom caused by two proton beams of energies 80 MeV and 100 MeV was verified using 16 optimal detectors. The thickness of the parallel-hole tungsten collimator of pitch 8 mm and width 7 mm was determined as 200 mm, and that of the GAGG scintillator was determined as 30 mm, by an optimization study. Further, 3-7 MeV and 2-7 MeV were obtained as the optimal EWs when the DOI and both the DOI and TOF techniques were applied for data processing, respectively; the detector performances were improved by about 38% and 167%, respectively, compared with that when applying only the 3-5 MeV EW. In this study, we confirmed that the PG distribution can be obtained by simply combining the 2-D parallel hole collimator and the PET detector module. In the future, we will develop an accurate 3-D dose evaluation technique using deep learning algorithms based on the image sets of dose, PG, and PET distributions for various proton energies.

     

     

    Affiliation

    Hyun Joon Choi  1 , Ji Won Jang, Wook-Geun Shin, Hyojun Park, Sebastien Incerti, Chul Hee Min
    1 Department of Radiation Convergence Engineering, Yonsei University, Wonju 26493, Republic of Korea.

  • 편집위원

    Proton In-vivo 연구는 여전히 핫 이슈이며 임상에서의 필요성으로 인하여 많은 관심을 불러일으킵니다.

    2020-07-02 14:45:51

  • 편집위원

    즉발감마와 양전자단층영상을 합친 시스템을 구성하여 환자 체내의 3차원 선량을 측정하고자 한 시도가 좋았으며 에너지 윈도우를 적절하게 설정하고 백그라운드의 감소에 기여하는 다양한 방법을 함께 사용하여 측정기 성능을 167%나 향상시켰다니 앞으로 양성자빔 등 입자빔 치료에 많은 도움이 될 것으로 기대한다.

    2020-07-02 15:33:19

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