The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)
- Volume 25 Issue 1
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- Pages.1-8
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- 2013
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- 1598-8449(pISSN)
The Effect of Partially Used High Energy Photon on Intensity-modulated Radiation Therapy Plan for Head and Neck Cancer
두경부암 세기변조방사선치료 계획 시 부분적 고에너지 광자선 사용에 따른 치료계획 평가
- Chang, Nam Joon (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam) ;
- Seok, Jin Yong (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam) ;
- Won, Hui Su (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam) ;
- Hong, Joo Wan (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam) ;
- Choi, Ji Hun (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam) ;
- Park, Jin Hong (Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam)
- 장남준 (분당서울대학교병원 방사선종양학과) ;
- 석진용 (분당서울대학교병원 방사선종양학과) ;
- 원희수 (분당서울대학교병원 방사선종양학과) ;
- 홍주완 (분당서울대학교병원 방사선종양학과) ;
- 최지훈 (분당서울대학교병원 방사선종양학과) ;
- 박진홍 (분당서울대학교병원 방사선종양학과)
- Received : 2013.02.15
- Accepted : 2013.03.10
- Published : 2013.03.31
Abstract
Purpose: A selection of proper energy in treatment planning is very important because of having different dose distribution in body as photon energy. In generally, the low energy photon has been used in intensity-modulated radiation therapy (IMRT) for head and neck (H&N) cancer. The aim of this study was to evaluate the effect of partially used high energy photon at posterior oblique fields on IMRT plan for H&N cancer. Materials and Methods: The study was carried out on 10 patients (nasopharyngeal cancer 5, tonsilar cancer 5) treated with IMRT in Seoul National University Bundang Hospital. CT images were acquired 3 mm of thickness in the same condition and the treatment plan was performed by Eclipse (Ver.7.1, Varian, Palo Alto, USA). Two plans were generated under same planing objectives, dose volume constraints, and eight fields setting: (1) The low energy plan (LEP) created using 6 MV beam alone, (2) the partially used high energy plan (PHEP) created partially using 15 MV beam at two posterior oblique fields with deeper penetration depths, while 6 MV beam was used at the rest of fields. The plans for LEP and PHEP were compared in terms of coverage, conformity index (CI) and homogeneity index (HI) for planning target volume (PTV). For organs at risk (OARs),
목 적: 체내에서 광자선은 에너지에 따라 다른 선량분포 특성을 보이기 때문에 치료계획 시 적절한 에너지 선택이 중요하다. 두경부암 세기변조방사선치료(intensity modulated radiation therapy, IMRT)는 주로 저에너지 광자선을 사용하는데, 본 연구에서는 후사방향 조사면에 부분적으로 고에너지 광자선을 사용하였을 때 치료계획에 미치는 영향을 알아보고자 한다. 대상 및 방법: 본원에서 두경부암 세기변조방사선치료를 시행한 10명(nasopharyngeal carcinoma 5, tonsilar carcinoma 5)의 환자를 대상으로 하였다. 동일한 조건하에 환자의 CT영상을 3 mm 두께로 획득하고 치료계획시스템은 Eclipse (Ver 7.1, Varian, Palo Alto, USA)를 사용하였다. 환자마다 8개 조사면으로 6 MV 에너지를 사용한 치료계획(low energy plan, LEP)과 상대적으로 투과 깊이가 깊은 후사방향의 2개 조사면에서 15 MV 에너지를 사용한 치료계획(partially used high energy plan, PHEP)을 각각 수립하였으며, 다른 치료계획조건들과 plan normalization은 동일하게 적용하였다. 수립된 치료계획을 평가하기 위해서 계획표적체적(planning target volume, PTV)의 coverage, conformity index (CI), homogeneity index (HI)를 비교하였고 양측 이하선의
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