Journal of radiological science and technology (대한방사선기술학회지:방사선기술과학)

Korean Society of Radiological Science (대한방사선과학회)
권호 표지

Verification of Non-Uniform Dose Distribution in Field-In-Field Technique for Breast Tangential Irradiation

유방암 절선조사 시 종속조사면 병합방법의 불균등한 선량분포 확인

  • Park, Byung-Moon (Department of Radiation Oncology, Konkuk University Medical Center) ;
  • Bae, Yong-Ki (Department of Radiation Oncology, Konkuk University Medical Center) ;
  • Kang, Min-Young (Department of Radiation Oncology, Konkuk University Medical Center) ;
  • Bang, Dong-Wan (Department of Radiation Oncology, Konkuk University Medical Center) ;
  • Kim, Yon-Lae (Department of Radiologic Technology, Choonhae Health College) ;
  • Lee, Jeong-Woo (Department of Radiation Oncology, Konkuk University Medical Center)
  • 박병문 (건국대학교병원 방사선종양학과) ;
  • 배용기 (건국대학교병원 방사선종양학과) ;
  • 강민영 (건국대학교병원 방사선종양학과) ;
  • 방동완 (건국대학교병원 방사선종양학과) ;
  • 김연래 (춘해보건대학 방사선과) ;
  • 이정우 (건국대학교병원 방사선종양학과)
  • Received : 2010.07.21
  • Accepted : 2010.08.30
  • Published : 2010.09.30
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Abstract

The study is to verify non-uniform dose distribution in Field-In-Field (FIF) technique using two-dimensional ionization chamber (MatriXX, Wellhofer Dosimetrie, Germany) for breast tangential irradiation. The MatriXX and an inverse planning system (Eclipse, ver 6.5, Varian, Palo Alto, USA) were used. Hybrid plans were made from the original twenty patients plans. To verify the non-uniform dose distribution in FIF technique, each portal prescribed doses (90 cGy) was delivered to the MatriXX. The measured doses on the MatriXX were compared to the planned doses. The quantitative analyses were done with a commercial analyzing tool (OmniPro IMRT, ver. 1.4, Wellhofer Dosimetrie, Germany). The delivered doses at the normalization points were different to average 1.6% between the calculated and the measured. In analysis of line profiles, there were some differences of 1.3-5.5% (Avg: 2.4%), 0.9-3.9% (Avg: 2.5%) in longitudinal and transverse planes respectively. For the gamma index (criteria: 3 mm, 3%) analyses, there were shown that 90.23-99.69% (avg: 95.11%, std: 2.81) for acceptable range ($\gamma$-index $\geq$ 1) through the twenty patients cases. In conclusion, through our study, we have confirmed the availability of the FIF technique by comparing the calculated with the measured using MatriXX. In the future, various clinical applications of the FIF techniques would be good trials for better treatment results.

본 연구의 목적은 유방암 환자의 절선조사 시 종속조사면 병합(FIF) 치료방법을 2차원 이온전리함을 이용하여 불균등한 선량분포를 확인하고자하였다. 실험을 위해 2차원 이온전리함 배열(MatriXX, Wellhofer Dosimetrie, Germany)와 치료계획장치(Eclipse, ver 6.5, Varian, Palo Alto, USA)가 사용되었다. 불균등한 선량분포 확인을 위해 FIF 방법으로 치료계획 한 20명의 환자를 선택하여 각각 90 cGy를 처방하여 하이브리드계획을 수행하였으며, 측정값과 비교를 위해 동일한 기하학적 조건에서 MatriXX를 이용해 측정하였다. 정량적인 분석을 위해 상용화된 분석 소프트웨어(OmniPro IMRT, ver, 1.4, Wellhofer, Dosimetrie, Germany)를 이용하여 분석하였다. 실험 결과로 기준점에 선량처방 시 계산값과 측정값이 평균 1.6% 차이를 보였고, 선형프로파일(Line-Profile)을 통해 분석한 결과 종단면에서는 1.3-5.5%(평균 : 2.4%), 횡단면에서는 0.9-3.9%(평균 : 2.5%)로 변동을 보였다. 감마인덱스 히스토그람(기준 : 3 mm, 3%)로 분석한 결과 90.23-99.69%(평균 : 95.11%, 표준편차 : 2.81) 범위를 나타냈다(유효범위 ; $\gamma$-index $\geq$ 1). 본 실험에서는 MatriXX 이용하여 측정한 결과 치료계획 선량과 측정값이 오차범위 이내로 일치하였으며, 향후 다양한 종양치료에 있어 FIF방법의 활용도를 높이는 연구가 필요하다고 생각한다.

Keywords

References

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