The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)
- Volume 23 Issue 2
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- Pages.97-102
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- 2011
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- 1598-8449(pISSN)
Evaluation of Uncertainty of IMRT QA Using 2Dimensional Array Detector for Head & Neck Patients
두경부암에서 2차원 배열 검출기를 이용한 IMRT QA의 불확실성에 대한 연구
- Ban, Tae-Joon (Department of Radiation Oncology, Asan Medical Center) ;
- Lee, Woo-Suk (Department of Radiation Oncology, Asan Medical Center) ;
- Kim, Dae-Sup (Department of Radiation Oncology, Asan Medical Center) ;
- Baek, Geum-Mun (Department of Radiation Oncology, Asan Medical Center) ;
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Kwak, Jung-Won
(Department of Radiation Oncology, Asan Medical Center)
- 반태준 (서울아산병원 방사선종양학과) ;
- 이우석 (서울아산병원 방사선종양학과) ;
- 김대섭 (서울아산병원 방사선종양학과) ;
- 백금문 (서울아산병원 방사선종양학과) ;
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곽정원
(서울아산병원 방사선종양학과)
- Received : 2011.05.15
- Accepted : 2011.07.29
- Published : 2011.09.30
Abstract
Purpose: IMRT QA using 2Dimensional array detector is carried out with condition for discrete dose distribution clinically. And it can affect uncertainty of evaluation using gamma method. We analyze gamma index variation according to grid size and suggest validate range of grid size for IMRT QA in Hospital. Materials and Methods: We performed QA using OniPro I'mRT system software version 1.7b on 10 patients (head and neck) for IMRT. The reference dose plane (grid size, 0.1 cm; location, [0, 0, 0]) from RTP was compared with the dose plane that has different grid size (0.1 cm, 0.5 cm, 1.0 cm, 2.0 cm, 4.0 cm) and different location (along Y-axis 0 cm, 0.2 cm, 0.5 cm, 1.0 cm). The gamma index variation was evaluated by observing the level of changes in Gamma pass rate, Average signal, Standard deviation for each case. Results: The average signal for each grid size showed difference levels of 0%, -0.19%, -0.04%, -0.46%, -8.32% and the standard deviation for each grid size showed difference levels of 0%, -0.30%, 1.24%, -0.70%, -7.99%. The gamma pass rate for each grid size showed difference levels of 0%, 0.27%, -1.43%, 5.32%, 5.60%. The gamma evaluation results according to distance in grid size range of 0.1 cm to 1.0 cm showed good agreement with reference condition (grid size 0.1 cm) within 1.5% and over 5% in case of the grid size was greater than 2.0 cm. Conclusion: We recognize that the grid size of gamma evaluation can make errors of IMRT QA. So we have to consider uncertainty of gamma evaluation according to the grid size and apply smaller than 2 cm grid size to reduce error and increase accuracy clinically.
목 적: 2차원 배열 검출기를 이용하여 세기변조 방사선 치료 품질관리를 시행할 때 정량적 분석을 위한 감마(