IMRT 2018

VMAT Machine Quality Control • Other tests have been proposed • Beam flatness and symmetry at selected dose rates • MLC position and speed (ionisation chamber, film): • Selected MLC patters, gantry and collimator angles • Rotation tests • Static 1x20cm 2 field and dynamic 1x20cm 2 delivered to cylindrical phantom

Consistency of output during gantry rotation. The dose distribution should be axially symmetric.

Profile at different doser rates. zoom

sliding window prescription with leaf pauses

Bedford, IJROBP 73, 2009. Commissioning of volumetric modulated arc therapy (VMAT) Bedford, J Appl Clin Med Phys 16, 2015. Quality control of VMAT synchronization using portal imaging Zwan, MedPhys 44, 2017: Commissioning and quality assurance for VMAT delivery systems: An efficient time- resolved system using real-time EPID imaging