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Correlation between gamma analysis for midline and lateralized tumors by using volumetric modulated arc therapy
Abstract
Purpose: The aim of this study was to evaluate the fluence for midline and lateralized tumors for volumetric modulated arc therapy (VMAT) by using a two-dimensional array.
Methods: For this study, we selected 60 patients who were undergoing VMAT. The octavius phantom was computed tomography (CT) scanned and imported to the planning system. Verification plans were created for each plan and exported. The measurements were performed using 2D seven29 ion chamber array. Fluence measurement values for all the delivered plans were analyzed using VeriSoft software. The TPS calculated values were then compared with the measured gamma values.
Results: The gamma pass percentage for midline tumors was found to be higher than that for lateralized tumors. The standard deviations between the gamma values for midline and lateralized tumors were 1.96 and 2.86, respectively. Moreover, the standard deviations between the point doses for midline and lateralized tumors were 0.360 and 0.283, respectively. The mean gamma passing rate was 96.96% for midline tumors and 96.57% for lateralized tumors for 3%DD/3-mm criteria. There is no significance found in the gamma values for midline and lateralized tumors with p-value 0.08.
Conclusion: No particular correlation was found between the gamma pass percentage for midline tumors and that for lateralized tumors. Only a marginal difference was found in the gamma pass percentage.
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Low DA, Dempsey JF. Evaluation of the gamma dose distribution comparison method. Med Phys. 2003;30:2455-64.
Harms WB Sr, Low DA, Wong JW, Purdy JA. A software tool for the quantitative evaluation of 3D dose calculation algorithms. Med Phys. 1998;25:1830-6.
Depuydt T, Van Esch A, Huyskens DP. A quantitative evaluation of IMRT dose distributions: refinement and clinical assessment of the gamma evaluation. Radiother Oncol. 2002;62:309-19.
Low DA, Harms WB, Mutic S, Purdy JA. A technique for the quantitative evaluation of dose distributions. Med Phys. 1998;25:656-61.
Kumar SA, Holla R, Sukumar P, et al. Treatment planning and dosimetric comparison study on two different volumetric modulated arc therapy delivery techniques. Rep PractOncolRadiother. 2012;18:87-94.
PTW Radiation Medicine QA Solutions, PTW, Freiburg, Germany.
Depuydt T, Van Esch A, Huyskens DP. A quantitative evaluation of IMRT dose distributions: refinement and clinical assessment of the gamma evaluation. RadiotherOncol. 2002;62:309-19.
Agazaryan N, Solberg TD, DeMarco JJ. Patient specific quality assurance for the delivery of intensity modulated radiotherapy. J ApplClin Med Phys. 2003;4:40-50.
Low DA. Gamma dose distribution evaluation tool. J Phys.: ConfSer2010;250: 012071.
Mancuso GM, Fontenot JD, Gibbons JP, Parker BC. Comparison of action levels for patient-specific quality assurance of intensity modulated radiation therapy and volumetric modulated arc therapy treatments. Med Phys. 2012; 39:4378-85.
Winiecki J, Morgaś T, Majewska K, Drzewiecka B. The gamma evaluation method as a routine QA procedure of IMRT.Reports of practical oncology and radiotherapy. 2009; 14:162-8.
Prescribing, Recording, and Reporting Photon-Beam Intensity-Modulated Radiation Therapy (IMRT): Contents. J ICRU. 2010;10:NP.
Poppe B, Blechschmidt A, Djouguela A, et al. Two- dimensional ionization chamber arrays for IMRT plan verification. Med Phys. 2006; 33:1005-15.
Li QL, Deng XW, Chen LX, et al. The angular dependence of a 2-dimensional diode array and the feasibility of its application in verifying the composite dose distribution of intensity-modulated radiation therapy. Chin J Cancer. 2010;29:617-20.
Chung H, Li J, Samant S. Feasibility of using two-dimensional array dosimeter for in vivo dose reconstruction via transit dosimetry. J ApplClin Med Phys. 2011;12:3370.
Mynampati DK, Yaparpalvi R, Hong L, et al. Application of AAPM TG 119 to volumetric arc therapy (VMAT). J ApplClin Med Phys. 2012;13:3382.
Van Esch A, Clermont C, Devillers M, et al. Online quality assurance of rotational radiotherapy treatment delivery by means of a 2D ion chamber array and the Octavius phantom. Med Phys. 2007; 34:3825-37.
DOI: http://dx.doi.org/10.14319/ijcto.33.24
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International Journal of Cancer Therapy and Oncology (ISSN 2330-4049)
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