Evaluation of the ability of a 2D ionisation chamber array and an EPID to detect systematic delivery errors in IMRT plans

17th International Conference on the Use of Computers in Radiation Therapy

物理学;计算机科学

Bawazeer, Omemh^1 ; Gray, Alison^2 ; Arumugam, Sankar^2 ; Vial, Philip^1,2 ; Thwaites, David^1 ; Descallar, Joseph^2 ; Holloway, Lois^1,2,3,4

Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia^1

Liverpool and Macarthur Cancer Therapy Center, Ingham Institute, Sydney, NSW, Australia^2

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

South West Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia^4

关键词: Electronic portal imaging devices;    Gamma analysis;    Intensity-modulated radiotherapy;    Multileaf collimators;    Pass rate;    Positional errors;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/489/1/012071/pdf
DOI  :  10.1088/1742-6596/489/1/012071

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

Two clinical intensity modulated radiotherapy plans were selected. Eleven plan variations were created with systematic errors introduced: Multi-Leaf Collimator (MLC) positional errors with all leaf pairs shifted in the same or the opposite direction, and collimator rotation offsets. Plans were measured using an Electronic Portal Imaging Device (EPID) and an ionisation chamber array. The plans were evaluated using gamma analysis with different criteria. The gamma pass rates remained around 95% or higher for most cases with MLC positional errors of 1 mm and 2 mm with 3%/3mm criteria. The ability of both devices to detect delivery errors was similar.