The Journal of Korean Society for Radiation Therapy (대한방사선치료학회지)

Korean Society for Radiation Therapy (대한방사선치료학회)
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The Study on the Effect of Target Volume in DQA based on MLC log file

MLC 로그 파일 기반 DQA에서 타깃 용적에 따른 영향 연구

  • Shin, Dong Jin (epartment of Radiation Oncology, Yonsei Cancer Center) ;
  • Jung, Dong Min (epartment of Radiation Oncology, Yonsei Cancer Center) ;
  • Cho, Kang Chul (epartment of Radiation Oncology, Yonsei Cancer Center) ;
  • Kim, Ji Hoon (epartment of Radiation Oncology, Yonsei Cancer Center) ;
  • Yoon, Jong Won (epartment of Radiation Oncology, Yonsei Cancer Center) ;
  • Cho, Jeong Hee (epartment of Radiation Oncology, Yonsei Cancer Center)
  • 신동진 (연세암병원 방사선종양학과) ;
  • 정동민 (연세암병원 방사선종양학과) ;
  • 조강철 (연세암병원 방사선종양학과) ;
  • 김지훈 (연세암병원 방사선종양학과) ;
  • 윤종원 (연세암병원 방사선종양학과) ;
  • 조정희 (연세암병원 방사선종양학과)
  • Published : 2020.12.27
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Abstract

Purpose: The purpose of this study is to compare and analyze the difference between the MLC log file-based software (Mobius) and the conventional phantom-ionization chamber (ArcCheck) dose verification method according to the change of target volume. Material and method: Radius 0.25cm, 0.5cm, 1cm, 2cm, 3cm, 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm with a Sphere-shaped target Twelve plans were created and dose verification using Mobius and ArcCheck was conducted three times each. The irradiated data were compared and analyzed using the point dose error value and the gamma passing rate (3%/3mm) as evaluation indicators. Result: Mobius point dose error values were -9.87% at a radius of 0.25cm and -4.39% at 0.5cm, and the error value was within 3% at the remaining target volume. The gamma passing rate was 95% at a radius of 9cm and 93.9% at 10cm, and a passing rate of more than 95% was shown in the remaining target volume. In ArcCheck, the average error value of the point dose was about 2% in all target volumes. The gamma passing rate also showed a pass rate of 98% or more in all target volumes. Conclusion: For small targets with a radius of 0.5cm or less or a large target with a radius of 9cm or more, considering the uncertainty of DQA based on MLC log files, phantom-ionized DQA is used in complementary ways to include point dose, gamma index, DVH, and target coverage. It is believed that it is desirable to verify the dose delivery through a comprehensive analysis.

목 적: 본 연구의 목적은 타깃 용적의 변화에 따라 MLC 로그 파일 기반 소프트웨어(Mobius)와 기존의 팬텀-전리함(ArcCheck) 선량 검증 방법 간에 차이를 비교 분석하는데 목적이 있다. 대상 및 방법: 반지름이 0.25cm, 0.5cm, 1cm, 2cm, 3cm, 4cm, 5cm, 6cm, 7cm, 8cm, 9cm, 10cm까지 총 12개의 球(구) 모양 타깃이 있는 플랜을 생성하고 Mobius와 ArcCheck을 사용한 선량 검증을 각각 3번씩 실시하였다. 조사된 데이터를 점선량 오차값과 감마 통과율(3%/3mm)을 평가지표로 하여 비교 분석하였다. 결 과: Mobius의 점선량 오차값은 반지름 0.25cm에서 -9.87%, 0.5cm에서 -4.39%로 나타났고, 나머지 타깃 용적에서 오차값은 3% 이내로 나타났다. 감마 통과율은 반지름 9cm에서 95%, 10cm에서 93.9%로 나타났고, 나머지 타깃 용적에서는 95% 이상의 통과율을 보였다. ArcCheck에서 점선량 평균 오차값은 모든 타깃 용적에서 2% 내외의 일치율을 보였다. 감마 통과율 역시 모든 타깃 용적에서 98% 이상의 통과율을 보였다. 결 론: 반지름 0.5cm 이하의 작은 타깃이나 반지름 9cm 이상의 큰 타깃에서는 MLC 로그 파일 기반 DQA의 불확실성을 고려하여, 팬텀-전리함 기반 DQA를 상호 보완해서 사용함으로써 점선량, 감마 지표, DVH, 타깃 포함 등의 종합적인 분석으로 선량 전달 검증을 하는 것이 바람직하다고 사료된다.

Keywords

References

  1. Jonas D. Fontenot: Feasibility of a remote, automated daily delivery verification of volumetric-modulated arc therapy treatments using a commercial record and verify system. JOURNAL OF APPLIEDCLINICAL MEDICAL PHYSICS 2012;13:114
  2. Zhen H, Nelms BE, Tome WA: Moving from gamma passing rates to patient DVH-based QA metrics in pretreatment dose QA. Med Phys 2011;38:5477-5489 https://doi.org/10.1118/1.3633904
  3. Nelms BE, Zhen H, Tom WA: Per-beam, planar IMRT QA passing rates do not predict clinically relevant patient dose errors. Med Phys 2011;38:1037-1044 https://doi.org/10.1118/1.3544657
  4. Young yih Han: Review on the Pre-treatment Quality Assurance for Intensity Modulated Radiation Therapy. PROGRESS in MEDICAL PHYSICS 2013;24:217-218
  5. Dong-Jin Kang, Jae-Yong Jung, Young-Joo Shin, et al: 소프트웨어 기반 정도관리 시스템을 이용한 부피세기 조절회전치료 환자 별 정도관리의 유용성 평가. Journal of Radiological Science and Technology 2018;41:40
  6. Gary A, Jay W, Nesrin D, et al.: IMRT commissioning: Multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys 2009;11:5370-5372
  7. Yair Hillman: Refinement of MLC modeling improves commercial QA dosimetry system for SRS and SBRT patient-specific QA. Medical Physics 2018;45:1355
  8. Ezzell GA, Burmeister JW, Dogan N, et al: IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys 2009;36:5359-5373 https://doi.org/10.1118/1.3238104
  9. Luis Alberto Vazquez-Quino, Claudia Ivette Huerta-Hernandez, Dharanipathy Rangaraj et al: Clinical Experience with Machine Log File Software for Volumetric-Modulated Arc Therapy Techniques. Journal of Physics 2017;847:276-279
  10. Jihun Kim, Min Cheol Han, Eungman Lee, et al: Detailed evaluation of Mobius3D dose calculation accuracy for volumetric modulated arc therapy. Physica Medica 2020;74:125-132 https://doi.org/10.1016/j.ejmp.2020.05.015
  11. C Nelson, M Garcia, E Calderon et al: Validation of Mobius 3D and FX for Elekta Linear Accelerators. Medical Physics 2016;43:3533
  12. Childress N, Chen Q, Rong Y. Parallel/Opposed: IMRT QA using treatmen tlog files is superior to conventional measurement-based method. J Appl Clin Med Phys. 2015;16:4-7 https://doi.org/10.1120/jacmp.v16i1.5385
  13. L. Dewayne, S. Sotirios, E. Joseph et al: Investigation of error detection capabilities of phantom, EPID and MLC log file based IMRT QA methods. Med. Phys. 2017;18:172-179
  14. R. Dharanipahy, Z. Mingyao, Y. Deshan et al: Catching errors with patient-specific pretreatment machine log file analysis. Radiat. Oncol. 2013;3:80-90