Progress in Medical Physics (한국의학물리학회지:의학물리)

Korean Society of Medical Physics (한국의학물리학회)
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Evaluation of Setup Errors for Tomotherapy Using Differently Applied Vacuum Compression with the Bodyfix Immobilization System

토모테라피 치료 시 Bodyfix System에서 진공압박에 따른 환자 위치잡이오차(Setup errors)의 평가

  • Jung, Jae-Hong (Department of Biomedical Engineering, The Catholic University of Korea College of Medicine) ;
  • Cho, Kwang-Hwan (Department of Radiation Oncology, Soonchunhyang University Bucheon Hospital) ;
  • Lee, Jeong-Woo (Department of Radiation Oncology, Konkuk University Medical Center, Research Institute of Health Sciences) ;
  • Kim, Min-Joo (Department of Biomedical Engineering, The Catholic University of Korea College of Medicine) ;
  • Lim, Kwang-Chae (Department of Radiation Oncology, Soonchunhyang University Bucheon Hospital) ;
  • Moon, Seong-Kwon (Department of Radiation Oncology, Soonchunhyang University Bucheon Hospital) ;
  • Kim, Yong-Ho (Department of Radiation Oncology, Soonchunhyang University Bucheon Hospital) ;
  • Suh, Tae-Suk (Department of Biomedical Engineering, The Catholic University of Korea College of Medicine)
  • 정재홍 (가톨릭대학교 의과대학 의공학교실) ;
  • 조광환 (순천향대학교 부천병원 방사선종양학과) ;
  • 이정우 (건국대학교병원 방사선종양학과) ;
  • 김민주 (가톨릭대학교 의과대학 의공학교실) ;
  • 임광채 (순천향대학교 부천병원 방사선종양학과) ;
  • 문성권 (순천향대학교 부천병원 방사선종양학과) ;
  • 김용호 (순천향대학교 부천병원 방사선종양학과) ;
  • 서태석 (가톨릭대학교 의과대학 의공학교실)
  • Received : 2011.05.03
  • Accepted : 2011.06.03
  • Published : 2011.06.30
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Abstract

The aim of this study is to evaluate the patient's setup errors in TomoTherapy (Hi-Art II, TomoTherapy, USA) Bodyfix system (Medical Intelligence, Ele-kta, Schwabmuchen, Germany) pressure in the vacuum compression, depending on and were evaluated. Bodyfix immobilization system and vacuum pressure was compression applied to the patients who received Tomotherapy thoracic and abdominal area, 21 patients were selected and TomoTehpay treatment total 477 of MVCT images were obtained. The translational (medial-lateral: ML, anterior-posterior: AP, superior-inferior: SI directions) and rolling were recorded and analyzed statistically. Using Pearson's product-moment coefficient and One-way ANOVA, the degree of correlation depending on the different vacuum pressure levels were statistically analyzed for setup errors from five groups (p<0.05). The largest average and standard deviation of systematic errors were 6.00, 5.95 mm in the AP and SI directions, respectively. The largest average of random errors were 4.72 mm in the SI directions. The correlation coefficients were 0.485, 0.244, and 0.637 for the ML-Roll, AP-Vector, and SI-Vector, respectively. SI-Vector direction showed the best relationship. In the results of the different degree of vacuum pressure in five groups (Pressure range: 30~70 mbar), the setup errors between the ML, SI in both directions and Roll p=0.00 (p<0.05) were shown significant differences. The average errors of SI direction in the vacuum pressure of 40 mbar and 70 mbar group were 4.78 mm and -0.74 mm, respectively. In this study, the correlation between the vacuum pressure and the setup-errors were statistically analyzed. The fact that setup-errors in SI direction is dependent in vacuum pressure considerly setup-errors and movement of interal organs was identified. Finally, setup-errors, and it, based on the movement of internal organs in Bodyfix system we should apply more than 50 mbar vacuum pressure. Based on the results of this study, it is suggested that accuracy of the vacuum pressure and the quantitative analysis of movement of internal organs and the tumor should be studied.

본 연구의 목적은 토모테라피(Hi-ArtII, TomoTherapy, USA) 치료 시 Bodyfix system (Medical Intelligence, Ele-kta, Schwabmuchen, Germany)에서 진공압박(Vacuum compression)에 따라 환자 위치잡이오차(Patient's setup-errors)를 평가하고자 하였다. Bodyfix system와 진공압박을 적용한 토모테라피를 이용하여 치료를 시행한 흉복부 환자 21명을 선정하였으며, 모든 환자는 치료 전 촬영된 총 477개의 메가볼테이지 전산화단층촬영(Mega-voltage computed tomography, MVCT)영상을 얻었다. 이를 통하여 확인된 좌우방향(Medial-Lateral direction, ML), 앞뒤방향(Anterior-Posterior direction, AP), 상하방향(Superior-Inferior direction, SI)과 SI중심축 회전각(Rotational angle of SI axis direction, Roll)에 대한 오차를 기록하고, 분석하였다. 세 방향 및 Roll에 대한 상관관계와 진공압박 정도가 다르게 적용된 다섯 그룹에 대하여 setup-errors를 분석하기 위해 각각 Pearson's product-moment coefficient와 One-way ANOVA를 이용하여 통계적으로 분석하였다(p<0.05). 분석결과 Systematic errors의 평균은 AP에서 6.00 mm, 표준편차는 SI에서 5.95 mm로 큰 오차를 보였다. Random errors의 평균은 SI방향에서 4.72 mm로 큰 오차가 발생하였다. 관계분석에서는 상관계수가 ML-Roll과 AP-Vector는 0.485, 0.244이고, SI-Vector에서 관계가 제일 높았다(0.637). 또한, 진공압박 정도가 다르게 적용된 다섯 그룹(Pressure range: 30~70 mbar) 사이의 setup errors를 분석한 결과 ML, SI방향과 Roll에서 모두 p=0.00 (p<0.05)로써 유의한 차이를 보였으며, SI방향에서 진공압박에 따른 오차 평균은 40 mbar과 70 mbar그룹에서 4.78 mm, -0.74 mm였다. 본 연구에서는 진공압박과 setup-errors의 평가를 통계적으로 분석하였으며, 압박 정도에 따라 SI방향에서 setup-errors의 차이를 확인하였다. 최종적으로 setup-errors와 내부장기의 움직임을 고려하자면 Bodyfix system을 이용한 진공압박을 적용시 최소 50 mbar 이상을 사용해야 할 것이다. 본 연구결과를 토대로 진공압박의 정확성과 내부장기 및 종양의 움직임을 정량적으로 분석할 필요가 있다고 판단된다.

Keywords

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