caa a22 4500 445304111 CHVBK 20180317142607.0 cr unu---uuuuu 170323e20100301xx s 000 0 eng 10.1007/s13246-010-0001-0 doi (NATIONALLICENCE)springer-10.1007/s13246-010-0001-0 Pre-treatment verification of intensity modulated radiation therapy plans using a commercial electronic portal dosimetry system [Elektronische Daten] [Kathleen Roxby, Jeffrey Crosbie] We commissioned a commercially available portal dosimetry system for quality assurance of intensity modulated radiation therapy (IMRT) treatment plans. The system included gamma analysis software to compare the measured and predicted fluence maps from individual IMRT fields. The portal dosimetry system was tested using six head and neck IMRT patient plans, and we demonstrated that the accuracy of the alignment of measured and predicted images improved by retracting and repositioning the electronic portal imaging device (EPID) at each new gantry angle. The mean gamma score (fraction of pixels passing the gamma criteria) for the six test plans (after initial testing and using the EPID retracting and repositioning method) was 0.987 (2SD=0.018), using gamma criteria of a dose difference of 2% of the maximum field dose and 2mm distance to agreement. The mean gamma score was 0.989 (2SD=0.017) for 24 head and neck IMRT patient plans carried out with portal dosimetry. Using gamma criteria of 2% maximum field dose and 2mm distance to agreement, a gamma score tolerance of 0.980 is a useful way of highlighting only those fields requiring further analysis. Portal dosimetry is a quick way of assessing individual field fluence distributions and can be integrated into an IMRT quality assurance programme. Australasian College of Physical Scientists and Engineers in Medicine, 2010 Portal dosimetry nationallicence IMRT nationallicence Quality assurance nationallicence Roxby Kathleen William Buckland Radiotherapy Centre, The Alfred, Commercial Road, 3004, Melbourne, VIC, Australia aut Crosbie Jeffrey William Buckland Radiotherapy Centre, The Alfred, Commercial Road, 3004, Melbourne, VIC, Australia aut Australasian Physical & Engineering Sciences in Medicine Springer Netherlands 33/1(2010-03-01), 51-57 0158-9938 33:1<51 2010 33 13246 https://doi.org/10.1007/s13246-010-0001-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s13246-010-0001-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Roxby Kathleen William Buckland Radiotherapy Centre, The Alfred, Commercial Road, 3004, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Crosbie Jeffrey William Buckland Radiotherapy Centre, The Alfred, Commercial Road, 3004, Melbourne, VIC, Australia aut NATIONALLICENCE 773 0- Australasian Physical & Engineering Sciences in Medicine Springer Netherlands 33/1(2010-03-01), 51-57 0158-9938 33:1<51 2010 33 13246 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer