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

Authors

Omemh Bawazeer, University of Sydney
Alison Gray, Liverpool and Macarthur Cancer Therapy Centres
Sankar Arumugam, Liverpool and Macarthur Cancer Therapy Centres
Philip J. Vial, Liverpool and Macarthur Cancer Therapy Centres, Liverpool Cancer Centre
David Thwaites, University of Sydney, University of SydneyFollow
Joseph Descallar, Liverpool and Macarthur Cancer Therapy Centres
Lois C. Holloway, Liverpool HospitalFollow

RIS ID

89855

Publication Details

Bawazeer, O., Gray, A., Arumugam, S., Vial, P., Thwaites, D., Descallar, J. & Holloway, L. (2014). Evaluation of the ability of a 2D ionisation chamber array and an EPID to detect systematic delivery errors in IMRT plans. Journal of Physics: Conference Series, 489 (1), 012071-1-012071-5. Journal of Physics: Conference Series

Abstract

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.