Impact of accelerator's gantry angle on multi-leaf collimator position accuracy / 中华放射肿瘤学杂志

Objective To study the impact of accelerator's gantry angle on MLC position accuracy. Methods Kodak X-omat-V Films were used, appropriate multi-leaf collimator positions and gantry angles were chosen, precise setup was needed , and the exposal films were analyzed by RIT113 software. Results At all conditions, most of the leaf position errors were less than 0. 5 mm. There were 2 pairs of leaf position errors larger than 1 mm when the gantry angle was 270° and the leaves moved from left to right. Conclu-sions Gantry angle can affect the accuracy of multi-leaf collimator position. Gravity and inertia increase the uncertainty of leaf position accuracy. Prieise setup is critical for the dose measurement.