Commissioning and testing of treatment planning system model of an Edge accelerator with a high-definition multi-leaf collimator
Ma Yangguang1, Wang Tao1, Hu Jinyan1, Zhang Zheng1, Wang Fangna1, Wang Xuemin2, Guo Yuexin1
1Department of Radiation Oncology, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052,China; 2Department of Radiotherapy Hospital Unit Radiation Therapy, Shanxi Provincial Tumor Hospital, Xi′an 710061,China
Abstract：Objective To investigate the commissioning and testing of the Eclipse model of an Edge accelerator with high-definition multi-leaf collimator (HD-MLC).Methods The percentage depth dose (PDD), profile, output factor measured by Razor and CC13 were statistically compared with the standard data. Penumbra, transmission factor (TF), leakage, concave-convex groove, accuracy of movement and dosimetry leaf gap (DLG) were measured with EBT3, electronic portal image device (EPID) and PTW SRS1000&SRS1500. The optimal DLG/TF was acquired when the γ pass rate of test cases was the highest. The point dose of regular fields, intensity-modulated radiation therapy (IMRT) and volume-modulated radiation therapy (VMAT) was verified with FC65-G. The planar dose of these case was verified with Octavius 4D and EBT3.Results The measured PDD data were consistent with the standard data. The measured penumbra of 3 cm and 4 cm square fields was smaller, whereas that of 6 cm square field was larger than the standard values. The left and right edge, field size, center of the field were distributed within the range of -1.0-0.4 mm、0.2-1.7 mm,-0.3-1.9 mm and -0.1-0.8 mm, respectively. The mean penumbra of the left and right MLC in different positions were (2.5±0.042) mm and (2.7±0.005) mm. The leakage of MLC was 0.009-0.016. The measured DLG/TF was 0.1861 cm/0.0116 and the optimal DLG/TF was 0.015 cm/0.014. The differences of point dose of all the test cases except the one which was in the low-dose area were within ±3%. Local and global γ pass rates of all IMRT were 79.81%-100% and 96.3%-100% (3%/3 mm), 71.3%-98.9% and 94.3%-99.8% for VMAT cases.Conclusions This method can accurately test and commission the Eclipse treatment planning model of Edge Linac equipped with HD-MLC.
Ma Yangguang,Wang Tao,Hu Jinyan et al. Commissioning and testing of treatment planning system model of an Edge accelerator with a high-definition multi-leaf collimator[J]. Chinese Journal of Radiation Oncology, 2019, 28(2): 113-118.
[1] Commissioning and quality assurance of computerized planning systems for radiation treatment of cancer[M].Austria:IAEA,2004. [2] Bedford JL,Warrington AP.Commiss ioning of volumetric modulated arc therapy (VMAT)[J].Int J Radiat Oncol Biol Phys,2009,73(2):537-545.DOI:10.1016/j.ijrobp.2008.08.055. [3] Ling CC,Zhang P,Archambault Y,et al. Commiss ioning and quality assurance of rapidArc radiotherapy delivery system[J].Int J Radiat Oncol Biol Phys,2008,72(2):575-581.DOI:10.1016/j.ijrobp.2008.05.060. [4] Bhagwat MS,Han Z,Ng SK,et al. An oscillating sweeping gap test for VMAT quality assurance[J].Phys Med Biol,2010,55(17):5029-5044.DOI:10.1088/0031-9155/55/17/010. [5] Sharma dS,Dongre PM,Mhatre V,et al. Physical anddosimetric characteristic of high-definition multileaf collimator (HDMLC) for SRS and IMRT[J].J Appl Clin Med Phys,2011,12(3):142-160.DOI:10.1120/jacmp.v12i3.3475. [6] Wen N,Li H,Song K,et al. Characteristics of a novel treatment system for linear accelerator-based stereotactic radiosurgery[J].J Appl Clin Med Phys,2015,16(4):125-148.DOI:10.1120/jacmp.v16i4.5313. [7] Godson H,Ravikumar M,Sathiyan S,et al. Analysis of small field percent depth dose and profiles:Comparison of measurements with various detectors and effects ofdetector orientation with different jaw settings[J].J Med Phys,2016,41(1):12.DOI:10.4103/0971-6203.177284. [8] Tanny S,Sperling N,Parsai EI.Correction factor measurements for multiple detectors used in small field dosimetry on the Varian Edge radio surgery system[J].Med Phys,2015,42(9):5370–5376.DOI:10.1118/1.4928602. [9] Qin Y,Zhong H,Wen N,ET AL.Deriving detector-specific correction factors for rectangular small fields using a scintillator detector[J].J Appl Clin Med Phys,2016,17(6):379-391.DOI:10.1120/jacmp.v17i6.6433. [10] Dieterich S,Sherouse GW.Experimental comparison of seven commercial dosimetry diodes for measurement of stereotactic radio surgery cone factors Experimental comparison of seven commercial dosimetry diodes for measurement of stereotactic radiosurgery cone factors[J].MedPhys,2011,38(20):4166-4173.DOI:10.1118/1.3592647. [11] Wu Q,Chang Z,Adamson J,et al. SU-E-T-560:a method todetermine optimal dynamic MLC parameters for Varian true beam with millennium MLC and HDMLC[J].Med Phys,2013,40(6 Pt 19):334.DOI:10.1118/1.4814989. [12] Kielar K,Mok E,Wang L,et al. Verification ofdosimetric accuracy on the trueBeam STx:rounded leaf effect of the high definition MLC[J].Med Phys,2012,39(10):6360–6371.DOI:10.1118/1.4752444. [13] Vial P,Oliver L,Greer PB,et al. An experimental investigation into the radiation field offset of adynamic multileaf collimator. Phys[J].Med Biol,2006,51(21):5517-5538.DOI:10.1088/0031-9155/51/21/009.
2019, Vol. 28 
