title: Evaluation of the sensitivity of two 3D diode array dosimetry systems to setup error for quality assurance (QA) of volumetric-modulated arc therapy (VMAT).
abstract: The purpose of this study is to evaluate the sensitivities of 3D diode arrays to setup error for patient-specific quality assurance (QA) of volumetric-modulated arc therapy (VMAT). Translational setup errors of ± 1, ± 2, and ± 3 mm in the RL, SI, and AP directions and rotational setup errors of ± 1° and ± 2° in the pitch, roll, and yaw directions were set up in two phantom systems, ArcCHECK and Delta4, with VMAT plans for 11 patients. Cone-beam computed tomography (CBCT) followed by automatic correction using a HexaPOD 6D treatment couch ensured the position accuracy. Dose distributions of the two phantoms were compared in order to evaluate the agreement between calculated and measured values by using γ analysis with 3%/3 mm, 3%/2 mm, and 2%/2 mm criteria. To determine the impact on setup error for VMAT QA, we evaluated the sensitivity of results acquired by both 3D diode array systems to setup errors in translation and rotation. For the VMAT QA of all patients, the pass rate with the 3%/3 mm criteria exceeded 95% using either phantom. For setup errors of 3 mm and 2°, respectively, the pass rates with the 3%/3mm criteria decreased by a maximum of 14.0% and 23.5% using ArcCHECK, and 14.4% and 5.0% using Delta4. Both systems are sensitive to setup error, and do not have mechanisms to account for setup errors in the software. The sensitivity of both VMAT QA systems was strongly dependent on the patient-specific plan. The sensitivity of ArcCHECK to the rotational error was higher than that of Delta4. In order to achieve less than 3% mean pass rate reduction of VMAT plan QA with the 3%/3 mm criteria, a setup accuracy of 2 mm/1° and 2 mm/2° is required for ArcCheck and Delta4 devices, respectively. The cumulative effect of the combined 2 mm translational and 1° rotational errors caused 3.8% and 2.4% mean pass rates reduction with 3%/3 mm criteria, respectively, for ArcCHECK and Delta4 systems. For QA of VMAT plans for nasopharyngeal cancer (NPC) using the ArcCHECK system, the setup should be more accurate.
authors.affiliation: Sichuan University West China Hospital. gjnick829@gmail.com.
authors.forename: Guangjun
authors.initials: G
authors.lastname: Li
authors.forename: Sen
authors.initials: S
authors.lastname: Bai
authors.forename: Nianyong
authors.initials: N
authors.lastname: Chen
authors.forename: Lansdale
authors.initials: L
authors.lastname: Henderson
authors.forename: Kui
authors.initials: K
authors.lastname: Wu
authors.forename: Jianghong
authors.initials: J
authors.lastname: Xiao
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Jiang
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Jiang
mesh_terms: D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000532:radiotherapy*; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care / Q000592:standards*; D011874:Radiometry / Q000295:instrumentation*; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D061106:Radiotherapy Setup Errors / Q000517:prevention & control / Q000706:statistics & numerical data*; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D012666:Semiconductors; D012680:Sensitivity and Specificity
references.citation: Int J Radiat Oncol Biol Phys. 2004 Nov 1;60(3):794-806
references.pmid: 15465196
references.citation: Radiother Oncol. 2010 May;95(2):153-7
references.pmid: 20116115
references.citation: Phys Med Biol. 2005 Jul 21;50(14):3361-73
references.pmid: 16177515
references.citation: Radiother Oncol. 2008 Nov;89(2):180-91
references.pmid: 18692929
references.citation: Int J Cancer. 2001 Dec 20;96(6):379-84
references.pmid: 11745509
references.citation: Med Phys. 2009 Sep;36(9):4197-212
references.pmid: 19810494
references.citation: Radiother Oncol. 2010 Feb;94(2):224-8
references.pmid: 20122745
references.citation: Int J Radiat Oncol Biol Phys. 2010 Jan 1;76(1):296-302
references.pmid: 19836151
references.citation: Int J Radiat Oncol Biol Phys. 2007 Sep 1;69(1):240-50
references.pmid: 17707278
references.citation: J Appl Clin Med Phys. 2011 Jan 31;12(2):3346
references.pmid: 21587178
references.citation: Int J Radiat Oncol Biol Phys. 2007 Mar 15;67(4):1220-8
references.pmid: 17336222
references.citation: Phys Med Biol. 2008 Oct 7;53(19):N359-70
references.pmid: 18758001
references.citation: Radiother Oncol. 2009 Oct;93(1):122-4
references.pmid: 19552979
references.citation: Med Phys. 2010 Jun;37(6):2837-46
references.pmid: 20632595
references.citation: Radiother Oncol. 2009 Nov;93(2):226-33
references.pmid: 19765846
references.citation: Med Phys. 2009 May;36(5):1813-21
references.pmid: 19544800
references.citation: Med Phys. 2007 Oct;34(10):3724-31
references.pmid: 17985617
references.citation: Med Phys. 2009 Jun;36(6):2328-39
references.pmid: 19610322
references.citation: Int J Radiat Oncol Biol Phys. 2002 Jun 1;53(2):453-63
references.pmid: 12023150
references.citation: Med Phys. 2008 Jun;35(6):2300-7
references.pmid: 18649462
references.citation: Int J Radiat Oncol Biol Phys. 2008 Nov 15;72(4):996-1001
references.pmid: 18455326
references.citation: Med Phys. 2008 Jan;35(1):310-7
references.pmid: 18293586
references.citation: Med Phys. 1999 Aug;26(8):1542-51
references.pmid: 10501054
references.citation: Acta Oncol. 2009;48(2):185-91
references.pmid: 18777411
references.citation: Med Phys. 2006 Apr;33(4):1005-15
references.pmid: 16696477
references.citation: Phys Med Biol. 2009 May 7;54(9):N167-76
references.pmid: 19384007
references.citation: Phys Med Biol. 2004 Jan 21;49(2):287-305
references.pmid: 15083672
references.citation: Med Phys. 2006 Jan;33(1):136-44
references.pmid: 16485420
references.citation: Int J Radiat Oncol Biol Phys. 2009 May 1;74(1):252-9
references.pmid: 19362244
references.citation: Acta Oncol. 2008;47(7):1438-43
references.pmid: 18654906
references.citation: Radiother Oncol. 2009 Nov;93(2):259-65
references.pmid: 19748146
references.citation: Med Phys. 2003 May;30(5):870-9
references.pmid: 12772995
references.citation: Med Phys. 2010 Jan;37(1):108-15
references.pmid: 20175471
references.citation: Radiother Oncol. 2010 May;95(2):142-8
references.pmid: 20188427
references.citation: Phys Med Biol. 2009 Jan 7;54(1):N9-20
references.pmid: 19075362
references.citation: J Appl Clin Med Phys. 2009 May 07;10(2):104-119
references.pmid: 19458595