Beam-on time and Treatment time analysis
Beam-on time was collected from Eclipse and RefleXion X1 TPS and compared. Total treatment time from imaging to end of treatment session was recorded using Aria offline review for Eclipse VMAT plans for every fifth fraction for each patient. Institutional guidelines for VMAT CSI treatment include imaging all isocenters separately using kV/kV orthogonal pairs, shifting and adjusting positioning to obtain an accurate match for each isocenter position. CBCT is used for the first fraction and every 5th fraction or if alignment is problematic. After the imaging and adjustments, each isocenter position is confirmed with planar MV port added to the arc to confirm the accuracy of the shifts.