The elementary discussion of volumetric modulated arc therapy using the orthogonal plane dose verification / 中华放射肿瘤学杂志

ABSTRACT

ObjectiveThis study was to explore the feasibility of using the orthogonal plane dose formed by the coronal and sagittal plane to verify the volumetric modulated arc therapy (VMAT) plan.MethodsThe VMAT plans of 12 patients were included in this study.The orthogonal plane dose formed by the coronal and sagittal plane were measured based on the combination of 2D ionization chamber array and multicube phantom,and the point dose were measured based on a multiple hole cylindrical phantom attached with two 0.125 cm3 ionization chamber probes.ResultsIn the measurement of the point dose,the average error was 1.5％ in high dose area ( more than 80％ of maximum),and 1.7％ in low dose area ( less than 80％ of maximum),respectively.The discrepancy of point dose measurement was 1.3％ between the 2D ionization chamber array and the VMAT planning system.In the measurement of the orthogonal plane dose,the pass rate of γ were 93.7％ for 2％/2 mm and 97.2％ for 3％/3 mm.ConclusionIt is reliable for using the orthogonal plane dose formed by the coronal and sagittal plane to verify the VMAT plan.