[an error occurred while processing this directive] | [an error occurred while processing this directive]
Study on the sensitivity of different 3D detectors to MLC positioning errors in volumetric modulated arc therapy (VMAT) plan for nasopharyngeal carcinoma
Zhang Peng1, Yan Bing2, Xue Xudong2, Wu Aidong1,2
1Department of Biomedical Engineering,College of Life Sciences,Anhui Medical University,Hefei 230032,China; 2Department of Radiation Oncology,First Affiliated Hospital of University of Science and Technology of China,Hefei 230001,China
AbstractObjective To compare the sensitivity of Delta4 and ArcCHECK 3D detectors to detect the multi-leaf collimator (MLC) positioning errors in the dose verification of volumetric modulated arc therapy (VMAT) plans for nasopharyngeal carcinoma (NPC). Methods Ten NPC patients receiving VMAT plans were selected. The positioning error of 0.5-4.0 mm was introduced into the leaves of each MLC segment in the original file to expand,contract or shift the whole segments. The possible positioning errors of MLC in the treatment of VMAT were simulated. The Delta4 and ArcCHECK were utilized to verify the measurements. The absolute gamma passing rate was compared between the calculated dose and the measured dose of the VMAT plan by using the paired t-test. Results When the evaluation criterion was taken as 3 mm/3%,the absolute passing rate verified by the original plans of two detectors was greater than 95%. The positioning errors of MLC expansion,contraction and shifting detected by Delta4 and ArcCHECK were 1.5 mm,1.0 mm,2.0 mm and 3.0 mm,1.0 mm,and 3.0 mm,respectively. When taking 2 mm/2% as the evaluation criterion,the absolute passing rate verified by the original plan was decreased significantly. Delta4 and ArcCHECK detected that the positioning errors of MLC expansion,contraction and shifting were 1.0 mm,1.0 mm,2.0 mm and 1.5 mm,0.5 mm,and 2.0 mm,respectively. Conclusions The dose verification of the VMAT plan for NPC by Delta4 and ArcCHECK can detect different types and sizes of MLC positioning errors,whereas the detection sensitivity slightly differs between Delta4 and ArcCHECK. Both of them are not sensitive to detect the MLC positioning errors less than 1.0 mm. It is fairly necessary to strengthen the quality assurance of MLC in the daily work.
Zhang Peng,Yan Bing,Xue Xudong et al. Study on the sensitivity of different 3D detectors to MLC positioning errors in volumetric modulated arc therapy (VMAT) plan for nasopharyngeal carcinoma[J]. Chinese Journal of Radiation Oncology, 2019, 28(7): 527-531.
Zhang Peng,Yan Bing,Xue Xudong et al. Study on the sensitivity of different 3D detectors to MLC positioning errors in volumetric modulated arc therapy (VMAT) plan for nasopharyngeal carcinoma[J]. Chinese Journal of Radiation Oncology, 2019, 28(7): 527-531.
[1]Otto K. Volumetric modulated arc therapy:IMRT in a single gantry arc[J]. Med Phys,2008,35(1):310-317. DOI:10.1186/1748-717X-9-167. [2]Kim JI,Park SY,Kim HJ,et al. The sensitivity of gamma-index method to the positioning errors of high-definition MLC in patient-specific VMAT QA for SBRT[J]. Radiat Oncol,2014,9(1):167. DOI:10.1186/1748-717X-9-167. [3]Heilemann G,Poppe B,Laub W. On the sensitivity of common gamma-index evaluation methods to MLC misalignments in Rapidarc quality assurance[J]. Med Phys,2013,40(3):031702 1-12. DOI:10.1118/1.4789580. [4]Boylan C,Mcwilliam A,Johnstone E,et al. The impact of continuously-variable dose rate VMAT on beam stability,MLC positioning,and overall plan dosimetry[J]. J Appl Clin Med Phys,2012,13(6):254-266. DOI:10.1120/ jacmp.v13i6.4023. [5]Coleman L,Skourou C. Sensitivity of volumetric modulated arc therapy patient specific QA results to multileaf collimator errors and correlation to dose volume histogram based metrics[J]. Med Phys,2013,40(11):111715. DOI:10.1118/1.4824433. [6]Vieillevigne L,Molinier J,Brun T,et al. Gamma index comparison of three VMAT QA systems and evaluation of their sensitivity to delivery errors[J]. Phys Med,2015,31(7):720-725. DOI:10.1016/j.ejmp.2015.05.016. [7]Bedford JL,Lee YK,Wai P,et al. Evaluation of the Delta4 phantom for IMRT and VMAT verification[J]. Phys Med Biol,2009,54(9):N167. DOI:10.1016/j.ejmp.2012.04.005. [8]Li G,Zhang Y,Jiang X,et al. Evaluation of the ArcCHECK QA system for IMRT and VMAT verification[J]. Eur J Med Phys,2013,29(3):295. DOI:10.1016/j.ejmp.2012.04.005. [9]Li G,Bai S,Chen N,et al. Evaluation of the sensitivity of two 3D diode array dosimetry systems to setup error for quality assurance (QA) of volumetric-modulated arc therapy (VMAT)[J]. J Appl Clin Med Phys,2013,14(5):13-24. DOI:10.1120/jacmp.v14i5.3828. [10]Klein EE,Hanley J,Bayouth J,et al. Task Group 142 report:quality assurance of medical accelerators[J]. Med Phys,2009,36(9):4197-4212. DOI:10.1118/1.3190392. [11]Mu G,Ludlum F,Xia P. Impact of MLC leaf position errors on simple and complex IMRT plans for head and neck cancer[J]. Phys Med Biol,2008,53(1):77-88. DOI:10.1088/ 0031-9155/53/1/005. [12]Yan G,Liu C,Simon TA,et al. On the sensitivity of patient-specific IMRT QA to MLC positioning errors[J]. J Appl Clin Med Phys,2009,10(1):120–128. DOI:10.1120/jacmp.v10i1.2915. [13]García-Vicente F,Fernández V,Bermüdez R,et al. Sensitivity of a helical diode array device to delivery errors in IMRT treatment and establishment of tolerance level for pretreatment QA[J]. J Appl Clin Med Phys,2012,13(1):111-123. DOI:10.1120/jacmp.v13i1.3660. [14]Oliver M,Bush K,Zavgorodni S,et al. Understanding the impact of RapidArc therapy delivery errors for prostate cancer[J]. J Appl Clin Med Phys,2011,12(3):32-43. DOI:10.1120/jacmp.v12i3.3409. [15]Oliver M,Gagne I,Bush K,et al. Clinical significance of multi-leaf collimator positional errors for volumetric modulated arc therapy[J]. Radiother Oncol,2010,97(3):554-560. DOI:10.1016/j.radonc.2010.06.013. [16]Liang B,Liu B,Zhou F,et al. Comparisons of volumetric modulated arc therapy (VMAT) quality assurance (QA) systems:sensitivity analysis to machine errors[J]. Radiat Oncol,2016,11(1):146. DOI:10.1186/s13014-016-0725-4. [17]倪昕晔,高留刚,林涛. Delta-4探测MLC细小位置偏差敏感性研究[J]. 中华放射肿瘤学杂志,2016,25(2):168-171. DOI:10.3760/cma.j.issn.1004-4221.2016.02.018. Ni XY,Gao LG,Lin T. Study of sensitivity for detecting small positional deviation of MLC by 3D Detector array Delta-4[J]. Chin J Radiat Oncol,2016,25(2):168-171. DOI:10.3760/cma.j.issn.1004-4221.2016.02.018. [18]程燕铭,胡彩容,阴晓娟,等. 鼻咽癌IMRT和VMAT计划对机器跳数和MLC误差剂量学敏感度对比研究[J]. 中华放射肿瘤学杂志,2017,26(10):1199-1203. DOI:10.3760/cma.j.issn.1004-4221.2017.10.019 Cheng YM,Hu CR,Yin XJ,et al. Dosimetric sensitivity with MU and MLC errors in IMRT versus VMAT plan for nasopharyngeal carcinoma[J]. Chin J Radiat Oncol,2017,26(10):1199-1203. DOI:10.3760/cma.j.issn.1004-4221.2017.10.019.
[1]
Zhejiang Cancer Diagnosis and Treatment QalityControl Center, Chen Xiaozhong, Zhu Yuan, Di Xiaoyun, Yang Yongting, Ge Minghua, Chen Ming. Quality control report of tumor radiotherapy in Zhejiang province[J]. Chinese Journal of Radiation Oncology, 2019, 28(5): 321-325.
2019, Vol. 28 
