BACKGROUND: In radiotherapy treatments, it is crucial to monitor the performance of 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 machine-related errors in treatments. METHODS: The EPID @entity11373 , gantry @entity11373 , changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the @entity11373 in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three @entity5377 linacs were investigated. RESULTS: The average EPID @entity11373 was within 1 mm for all tested linacs. Two machines showed >1 mm gantry @entity11373 . Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1   in all machines. The maximum @entity11373 in leaf bank assembly was <1 mm. CONCLUSION: The method and software developed in this study provide a simple tool for effective investigation of the behavior of @entity5377 linac components with @entity717 . Such a comprehensive study has been performed for the first time on @entity5377 machines.

Investigation of the mechanical performance of XXXX linacs components during arc: gantry, MLC, and electronic portal imaging device.

@entity717 :: ('MESH:D009069', 'Disease') :: ['gantry rotation'] @entity11373 :: ('6295', 'Gene') :: ['sag'] @entity5377 :: ('MESH:D053560', 'Disease') :: ['Siemens']
@entity5377 :: (MESH:D053560,Disease) :: ['Siemens']
