IMRT 2018

Dose rate vs. gantry speed, DRGS test

The test relies on correct MLC positioning Seven segments with • Combinations of dose rate and gantry speed • Separate parts of the EPID/film (static MLC defined 20x200mm 2 field) • Dose: Constant and identical in each segment

7: DR 600 MU/min GS 4.4 ° /s 6: DR 592 MU/min GS 4.8 ° /s 5: DR 524 MU/min GS 4.8 ° /s 4: DR 417 MU/min GS 4.8 ° /s 3: DR 314 MU/min GS 4.8 ° /s 2: DR 210 MU/min GS 4.8 ° /s 1: DR 105 MU/min GS 4.8 ° /s

Ling IJBOP 72,2008 Commissioning and quality assurance of rapidarc radiotherapy delivery system Jørgensen MedPhys 38, 2011. Tolerance levels of EPID-based quality control for volumetric modulated arc therapy