Radiation Oncology Journal

  • 제25권4호
  • /
  • Pages.249-260
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  • 2007
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  • 2234-1900(pISSN)
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  • 2234-3156(eISSN)
대한방사선종양학회 (The Korean Society for Radiation Oncology)
권호 표지

원격 품질 보증 시스템을 사용한 세기변조 방사선치료의 예비 모니터링 결과

A Pilot Study for the Remote Monitoring of IMRT Using a Head and Neck Phantom

  • 한영이 (성균관대학교 의과대학 삼성서울병원 방사선종양학과) ;
  • 신은혁 (성균관대학교 의과대학 삼성서울병원 방사선종양학과) ;
  • 임천일 (한국식품의약품 안전청) ;
  • 강세권 (한림대학교 의과대학 강동성심병원 방사선종양학과) ;
  • 박성호 (울산대학교 의과대학 서울아산병원 방사선종양학과) ;
  • 라정은 (가톨릭대학교 의과대학 의공학교실) ;
  • 서태석 (가톨릭대학교 의과대학 의공학교실) ;
  • 윤명근 (국립암센터 양성자 치료센터) ;
  • 이세병 (국립암센터 양성자 치료센터) ;
  • 주상규 (성균관대학교 의과대학 삼성서울병원 방사선종양학과) ;
  • 안용찬 (성균관대학교 의과대학 삼성서울병원 방사선종양학과)
  • Han, Young-Yih (Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Shin, Eun-Hyuk (Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Lim, Chun-Il (Korea Food and Drug Administration (KFDA)) ;
  • Kang, Se-Kwon (Department of Radiation Oncology, Kang Dong Sacred Heart Hospital, College of Medicine, Hallym University) ;
  • Park, Sung-Ho (Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan) ;
  • Lah, Jeong-Eun (Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea) ;
  • Suh, Tae-Suk (Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea) ;
  • Yoon, Myong-Geun (Proton Therapy Center, National Cancer Center) ;
  • Lee, Se-Byeong (Proton Therapy Center, National Cancer Center) ;
  • Ju, Sang-Gyu (Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine) ;
  • Ahn, Yong-Chan (Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine)
  • 발행 : 2007.12.30
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초록

목적: 국내에서 시행되고 있는 세기변조 방사선 치료(IMRT)의 품질 향상을 위하여, 우편으로 시행하는 원격 품질보증 시스템을 개발하고, 이 시스템의 정확성 확인에 이어서, 국내 의료기관에서 타당성을 검증한다. 대상 및 방법: 원격 품질 보증 시스템은 두경부 팬톰과 IMRT의 치료계획 지침을 포함하는 사용자 설명서로 구성되어 있다. 두경부 용 팬톰은 내부에 CT영상에서 분별이 가능한 모사 치료표적(target)과 3개의 위험장기(좌, 우 이하선, 척추)를 포함하고 있으며, 각 모사 장기의 중심에서 열형광 소자(TLD)를 삽입하여 흡수 선량을 측정하도록 구성되어있다. 또한 2차원상의 선량분포를 확인 가능하도록 Gafchromic@EBT 필름을 2개의 평면에 삽입하도록 고안하였다. 고안된 팬톰과 사용자 설명서를 국내의 4개 기관에 보내어, 팬톰에 대한 IMRT치료계획을 수행하고 치료를 시행하였다. 치료계획 시 예측된 치료표적과 위험장기 내의 각 TLD에서 예측되는 절대 선량과 TLD의 측정값을 비교하였고, 횡단면에서 면의 중심을 지나는 2개의 직교하는 수평선과 수직선상에서 예측되는 상대적인 선량분포 값과 실제 측정값을 비교하였다. 결 과: 치료 표적에서의 선량측정 값은 모두 치료계획시의 예측값과 3% 오차 안에서 일치하였으나(평균오차, 1.5%), 좌우 이하선에 해당하는 위험장기에서는 최소 3.3%최대 19.8%의 차이를 보였다. 척추에 해당하는 위험장기에서의 오차의 범위는 $0.7{\sim}1.4%$였다. 2차원 선량분포는 3개 기관에 대한 자료를 분석하였는데, 직선상에서 예측 값과 5%이상의 차이를 보이는 비율이 수평선에서는 $7{\sim}27%$, 수직선상에서는 $7{\sim}14%$였다. 결 론: 본 연구에서 개발한 IMRT치료의 원격 품질보증 시스템과 사용자 설명서는 국내 시행이 가능한 상태로 판단된다. 그러나, 시행 시에 치료표적에서의 오차는 크지 않을 것으로 예상이 되지만, 위험장기에서의 오차는 클 것으로 예상되며, 이에 대한 방안이 마련돼야 할 것이며, 또한 임상의 중요성과 연관해 의미 있는 2차원 선량분포의 기준 마련이 요구된다.

Purpose: In order to enhance the quality of IMRT as employed in Korea, we developed a remote monitoring system. The feasibility of the system was evaluated by conducting a pilot study. Materials and Methods: The remote monitoring system consisted of a head and neck phantom and a user manual. The phantom contains a target and three OARs (organs at risk) that can be detected on CT images. TLD capsules were inserted at the center of the target and at the OARs. Two film slits for GafchromicEBT film were located on the axial and saggital planes. The user manual contained an IMRT planning guide and instructions for IMRT planning and the delivery process. After the manual and phantom were sent to four institutions, IMRT was planed and delivered. Predicted doses were compared with measured doses. Dose distribution along the two straight lines that intersected at the center of the axial film was measured and compared with the profiles predicted by the plan. Results: The measurements at the target agreed with the predicted dose within a 3% deviation. Doses at the OARs that represented the thyroid glands showed larger deviations (minimum 3.3% and maximum 19.8%). The deviation at OARs that represented the spiral cord was $0.7{\sim}1.4%$. The percentage of dose distributions that showed more than a 5% of deviation on the lines was $7{\sim}27%$ and $7{\sim}14%$ along the horizontal and vertical lines, respectively. Conculsion: Remote monitoring of IMRT using the developed system was feasible. With remote monitoring, the deviation at the target is expected to be small while the deviation at the OARs can be very large. Therefore, a method that is able to investigate the cause of a large deviation needs to be developed. In addition, a more clinically relevant measure for the two-dimensional dose comparison and pass/fail criteria need to be further developed.

키워드

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