PTV
Gantry Angle
Contribution of dose to a small subvolume of the target volume from a small angle
A
i
DR
i
G
i
GS
i
A
i+2
DR
i+2
G
i+3
GS
i+3
A
i+1
DR
i+1
G
i+1
GS
i+1
VMAT subsequent segments
Gantry angle rotation
Intensity modulation and interconnectivity: VMAT