Table 1.

Dosimetric parameters reported by IROC–H [11] for 6 MV beams from Clinac 2100 linacs, and for 6 MV FFF beams from TrueBeam linacs

Parameter	Field size (cm2)	N Clinac 2100	N TrueBeam
PDD at dmax	10 ×10	116	11
PDD at 5, 15, and 20 cm	6 ×6	99	11
	10 ×10	116	11
	20 ×20	99	11
Off-axis ratios at 5 cm left,	40 ×40	116	11
10 cm avg.,
and 15 cm left
Open field OF at dmax	6 ×6	104	11
	15 ×15
	20 ×20
	30 ×30
IMRT-style OF at 10 cm	2 ×2	4	11
	3 ×3
	4 ×4
	6 ×6
SBRT-style OF at 10 cm	2 ×2	20	4
	3 ×3
	4 ×4
	6 ×6

N represents the number of linacs studied for each parameter. Data for Clinac 2100 were taken from the class ‘2100’, except for the SBRT–style OF, which were taken from the class ‘Base’. Data for TrueBeam were taken from the class ‘TB–FFF’