TY - JOUR
T1 - A comprehensive study of the mechanical performance of gantry, EPID and the MLC assembly in Elekta linacs during gantry rotation
AU - Rowshanfarzad, Pejman
AU - Riis, H.L.
AU - Zimmermann, S.J.
AU - Ebert, Martin
PY - 2015
Y1 - 2015
N2 - ©2015 The Authors. Objective: In radiotherapy treatments, it is crucial to monitor the performance of linear accelerator (linac) components, including gantry, collimation system and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machinerelated errors in treatments. Methods: The EPID sag, gantry sag, changes in source-todetector distance (SDD), EPID and collimator skewness, EPID tilt and the sag in leaf bank assembly owing to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with 5 ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of the image data. Nine Elekta AB (Stockholm, Sweden) linacs of different models and number of years in service were investigated. Results: The average EPID sag was within 2mm for all tested linacs. Some machines showed >1-mm gantry sag. Changes in the SDD values were within 1.3 cm. EPID skewness and tilt values were
AB - ©2015 The Authors. Objective: In radiotherapy treatments, it is crucial to monitor the performance of linear accelerator (linac) components, including gantry, collimation system and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machinerelated errors in treatments. Methods: The EPID sag, gantry sag, changes in source-todetector distance (SDD), EPID and collimator skewness, EPID tilt and the sag in leaf bank assembly owing to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with 5 ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of the image data. Nine Elekta AB (Stockholm, Sweden) linacs of different models and number of years in service were investigated. Results: The average EPID sag was within 2mm for all tested linacs. Some machines showed >1-mm gantry sag. Changes in the SDD values were within 1.3 cm. EPID skewness and tilt values were
U2 - 10.1259/bjr.20140581
DO - 10.1259/bjr.20140581
M3 - Article
C2 - 25906294
SN - 0007-1285
VL - 88
SP - 20140581
JO - British Journal of Radiology
JF - British Journal of Radiology
IS - 1051
ER -