Browsing by Author "Hsieh, Chen-Hsi"

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Patient delivery quality assurance for linac-based IMRT and helical tomotherapy using solid state detectors
(2011-12-01)
Chong, Ngot Swan
;
Lee, Jason J. S.
;
Kung, Wei-Hsiang
;
Chen, Chien-An
;
Hsieh, Chen-Hsi
The purpose of this study is to demonstrate how to perform and define appropriate action levels for the intensity-modulated radiation therapy (IMRT) delivery quality assurance (DQA) for both linear accelerator (linac) and helical tomotherapy (HT) plans using a 2D array diode detector. MapCHECK (Sun Nuclear, Melbourne, FL, USA) was used to perform the DQA measurements of patient plans at various sites: brain, head and neck, chest, abdomen, pelvis, spine, bone and others. The measured and planned doses were compared using gamma analysis with a total dose discrepancy of 3% or a gradient difference of 3 mm criteria. DQAs for 507 HT and 380 linac-based IMRT plans were performed, and the mean diode percentage passing rates for 3%/3 mm criteria were 93.8% and 95.1% respectively. For HT delivery, 4.6% and 9.5% of the plans had the passing rates below 80% and 85%, while for linac-based IMRT, 7.4% of the plans had the passing rates lower than 90%. Applying confidence limit with multiplier of 1, action levels for passing rates of 87% and 90% are recommended for HT and IMRT plans respectively. (C) 2011 Elsevier Ltd. All rights reserved.