731 / 1542
VMAT
Aperture weights (MU) variation:
Gantry speed
(mechanical limitations)
Dose rate variations
Transition between adjacent apertures: MLC motion trajectories
→
as the gantry rotates the beam is on
→
the subfields of adjacent beam
angles should not require the MLC leaves to travel long distances
(ensuring smooth leaf motion in the leaf-sequencing algorithm)
Beam fluence:
1. The MLC leaf trajectories as a function of time
2. The gantry angle as a function of time
3. The dose rate as a function of time