Three dimensional dose verification of VMAT plans using the Octavius 4D dosimetric system

8th International Conference on 3D Radiation Dosimetry

Arumugam, Sankar^1 ; Xing, Aitang^1 ; Young, Tony^1 ; Thwaites, David^2 ; Holloway, Lois^1,2,3,4

Liverpool and Macarthur Cancer Therapy Centres, Ingham Institute, NSW, Australia^1

Institute of Medical Physics, School of Physics, University of Sydney, NSW, Australia^2

Centre for Medical Radiation Physics, University of Wollongong, NSW, Australia^3

University of New South Wales, NSW, Australia^4

关键词: 2D detector;    Depth dose;    Detector size;    Dose verification;    Dosimetric systems;    High dose;    Static fields;    Treatment planning systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/573/1/012081/pdf
DOI  :  10.1088/1742-6596/573/1/012081

来源: IOP

【 摘 要 】

The Octavius 4D dosimetric system generates a 3D dose matrix based on a measured planar dose and user supplied Percentage Depth Dose (PDD) data. The accuracy of 3D dose matrices reconstructed by the Octavius 4D dosimetric system was systematically studied for an open static field, an open arc field and clinical VMAT plans. The Octavius reconstructed 3D dose matrices were compared with the Treatment Planning System (TPS) calculated 3D dose matrices using 3D gamma (γ) analysis with 2%/2mm and 3%/3mm tolerance criteria. The larger detector size in the 2D detector array of the Octavius system resulted in failed voxels in the high dose gradient regions. For the open arc fields mean (1σ) γ pass rates of 84.5(8.9) % and 94.2(4.5) % were observed with 2%/2mm and 3%/3mm tolerance criteria respectively and for clinical VMAT plans mean (1σ) γ pass rates of 86.8(3.5) % and 96.7(1.4) % were observed.