Table 1.

γ‐index off‐axis analysis of EPID and PTW ion chamber array measurements

Field size [cm2]	6 MV WFF γ‐index pass rate (%)			6 MV FFF γ‐index pass rate (%)
	3 mm/3%	2 mm/2%	1 mm/1%	3 mm/3%	2 mm/2%	1 mm/1%
4 × 4	100	96.3	75.4	99.5	92.5	67.9
10 × 10	100	99.8	87.2	99.7	97	82.2
15 × 15	100	99.9	92.3	100	98.8	90.2
	10 MV WFF γ‐index pass rate (%)			10 MV FFF γ‐index pass rate (%)
4 × 4	99.9	96.1	74.3	99.6	92.3	68.2
10 × 10	100	99.2	86.6	99.8	97.4	81.7
15 × 15	99.8	99.4	91.5	100	98.4	90.1
	15 MV WFF γ‐index pass rate (%)
4 × 4	99.6	96.6	73.9
10 × 10	99.7	98.3	85.8
15 × 15	99.4	98.1	91.2