Abstract Objective To investigate the feasibility of detector array in Monaco modeling for MLC parameters adjustment. Methods One parameter was fixed, and then the other parameter was changed. The γ pass rates of the test beams, namely 3ABUT, 7SegA, and FOUR L, were assessed to determine the values of leaf transmission and leaf offset. A total of 12 tumor cases from different anatomical sites were randomly selected. Two-dimensional dose verification (rack angle zero) of Step& Shot and dMLC plans as well as three-dimensional dose validation of VMAT plan were performed using Octavius 4D system. The γ pass rates were analyzed at a standard of 3%/3 mm. Meanwhile, the point dose verification for these three plans was analyzed to obtain the dose deviations. Results The values of leaf transmission and leaf offset were 0.0105 and-0.08 mm, respectively. The average γ pass rates (%) of Step& Shot, dMLC, and VMAT plans were 88.59±2.94, 87.81±3.28, and 87.45±2.24 before adjustment and 98.45±1.23, 98.9±1.01, and 96.03±1.66 after adjustment. In addition, the average dose deviations (%) according to the point dose verification were 0.85±0.75, 0.95±0.39, and 0.98±0.40 before adjustment and 0.97±0.57, 1.08±0.76, and 0.86±0.45 after adjustment. Conclusions Octavius detector 729 ionization chamber array is a feasible and reliable device in Monaco modeling for MLC parameters adjustment.
Niu Zhenyang,Fei Zhenle,Duan Zongjin et al. Application of detector array in treatment planning system modeling adjustment[J]. Chinese Journal of Radiation Oncology, 2017, 26(7): 806-809.
Niu Zhenyang,Fei Zhenle,Duan Zongjin et al. Application of detector array in treatment planning system modeling adjustment[J]. Chinese Journal of Radiation Oncology, 2017, 26(7): 806-809.
[1] 石梅,马林,周振山.肿瘤放射治疗新技术及临床实践[M].西安:第四军医大学出版社,2015:164-182. Shi M,Ma L,Zhou ZS.New techniques and clinical practice of tumor radiotherapy[M].Xi’an:The Fourth Military Medical University Press,2015:164-182. [2] Herzen J,Todorovic M,Cremers F,et al. Dosimetric evaluation of a 2D pixel ionization chamber for implementation in clinical routine[J].Phys Med Biol,2007,52(4):1197-1208.DOI:10.1088/0031-9155/52/4/023. [3] Li JG,Yan GH,Liu C.Comparison of two commercial detector arrays for IMRT quality assurance[J].J Appl Clin Med Phys,2009,10(2):62-74.DOI:10.1120/jacmp.v10i2.2942. [4] Spezi E,Angelini AL,Romani F,et al. Characterization of a 2D ion chamber array for the verification of radiotherapy treatments[J].Phys Med Biol,2005,50(14):3361-3373.DOI:10.1088/0031-9155/50/14/012. [5] McGarry CK,O’Connell BF,Grattan MWD,et al. Octavius 4D characterization for flattened and flattening filter free rotational deliveries[J].Med Phys,2013,40(9):091707.DOI:10.1118/1.4817482. [6] 刘苓苓,费振乐,李兵兵,等.呼吸幅度对旋转容积调强剂量分布的影响研究[J].中华放射医学与防护杂志,2016,36(3):220-224.DOI:10.3760/cma.j.issn.0254-5098.2016.03.012. Liu LL,Fei ZL,Li BB,et al. Effect of respiratory amplitude on the dose distribution of volumetric modulated arc therapy[J].Chin J Radiol Med Prot,2016,36(3):220-224.DOI:10.3760/cma.j.issn.0254-5098.2016.03.012. [7] 杨金磊,刘博宇,路双臣,等.Monaco与Pinnacle计划系统在肺癌容积旋转调强计划中的比较[J].中华放射医学与防护杂志,2015,35(2):119-122.DOI:10.3760/cma.j.issn.0254-5098.2015.02.010. Yang JL,Liu BY,Lu SC,et al. Comparison of Monaco and Pinnacle treatment planning systems in volumetric modulated arc therapy optimization for lung cancer[J].Chin J Radiol Med Prot,2015,35(2):119-122.DOI:10.3760/cma.j.issn.0254-5098.2015.02.010. [8] Lang S,Reggiori G,Vaqué JP,et al. Pretreatment quality assurance of flattening filter free beams on 224 patients for intensity modulated plans:a multicentric study[J].Med Phys,2012,39(3):1351-1356.DOI:10.1118/1.3685461. [9] Ezzell GA,Burmeister JW,Gogan N,et al. IMRT commissioning:multiple institution planning and dosimetry comparisons,a report from AAPM Task Group 119[J].Med Phys,2009,36(11):5359-5373.DOI:10.1118/1.3238104. [10] Basran PS,Woo MK.An analysis of tolerance levels in IMRT quality assurance procedures[J].Med Phys,2008,35(6):2300-2307.DOI:10.1118/1.2919075. [11] Fippel M.Fast Monte Carlo dose calculation for photon beams based on the VMC electron algorithm[J].Med Phys,1999,26(8):1466-1475.DOI:10.1118/1.598676. [12] Fippel M,Haryanto F,Dohm O,et al. A virtual photon energy fluence model for Monte Carlo dose calculation[J].Med Phys,2003,30(3):301-311.DOI:10.1118/1.1543152. [13] 石锦平,陈立新,谢秋英,等.容积调强弧形治疗冠矢状面剂量验证的初步探讨[J].中华放射肿瘤学杂志,2012,21(4):377-380.DOI:10.3760/cma.j.issn.1004-4221.2012.04.024. Shi JP,Chen LX,Xie QY,et al. The elementary discussion of volumetric modulated arc therapy using the orthogonal plane dose verification[J].Chin J Radiat Oncol,2012,21(4):377-380.DOI:10.3760/cma.j.issn.1004-4221.2012.04.024. [14] 张建英.插值对二维电离室矩阵调强验证Gamma通过率的影响[J].中国医学物理学杂志,2010,27(6):2224-2226.DOI:10.3969/j.issn.1005-202X.2010.06.006. Zhang JY.The effort to Gamma pass rates of interpolation during the 2D chamber array IMRT QA[J].Chin J Med Phys,2010,27(6):2224-2226.DOI:10.3969/j.issn.1005-202X.2010.06.006.
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