Table 1.

Mean (±1SD) gamma pass rate difference between the original ArcCheck dose matrix resolution of 5 mm (left columns) and 1mm resolution (right column) for lung SABR VMAT plans delivered with different collimator, MLCFS and MLCShift variations. A lower gamma pass rate number indicates greater sensitivity to the introduced‐variation.

Variation type/magnitude	Gamma pass rate (%, mean ± SD) ArcCheck original image resolution of (5 mm)				Gamma pass rate (%, mean ± SD) ArcCheck image resolution of (1 mm)
	3%/3 mm	2%/2 mm	2%/1 mm	1%/1 mm	3%/3 mm	2%/2 mm	2%/1 mm	1%/1 mm
Collimator (degree)
+1°	99.68 ± 0.0	99.44 ± 0.0	99.44 ± 0.0	98.84 ± 0.0	99.97 ± 0.0	99.84 ± 0.0	99.61 ± 0.0	99.04 ± 0.0
+5°	91.53 ± 4.9	82.97 ± 7.2	82.97 ± 7.2	67.93 ± 6.3	99.06 ± 0.1	93.55 ± 2.5	84.23 ± 7.1	69.83 ± 7.6
−2°	99.40 ± 0.0	99.07 ± 0.0	99.07 ± 0.0	96.19 ± 0.0	99.96 ± 0.0	99.67 ± 0.0	99.21 ± 0.0	96.98 ± 0.0
−5°	92.96 ± 3.9	86.01 ± 6.5	86.01 ± 6.5	70.59 ± 4.7	98.38 ± 1.0	93.50 ± 3.1	87.20 ± 6.9	72.36 ± 5.7
MLC field size (mm)
+1	78.87 ± 8.5	64.01 ± 8.6	64.01 ± 8.6	30.27 ± 10.8	94.08 ± 5.3	79.53 ± 7.3	64.61 ± 8.3	30.17 ± 11.1
+2	65.20 ± 0.0	46.36 ± 0.0	46.36 ± 0.0	16.89 ± 0.0	91.54 ± 0.0	66.06 ± 0.0	46.74 ± 0.0	16.52 ± 0.0
+5	23.70 ± 0.0	16.03 ± 0.0	16.03 ± 0.0	15.89 ± 0.0	41.34 ± 0.0	21.94 ± 0.0	15.54 ± 0.0	15.44 ± 0.0
−1	75.91 ± 8.4	60.67 ± 4.2	60.67 ± 4.2	28.18 ± 4.8	92.53 ± 5.1	77.67 ± 4.3	61.48 ± 3.7	28.28 ± 4.9
−2	56.69 ± 0.0	30.74 ± 0.0	30.74 ± 0.0	16.40 ± 0.0	74.26 ± 0.0	45.93 ± 0.0	30.73 ± 0.0	16.17 ± 0.0
MLC shift (mm)
+1	98.02 ± 2.7	94.49 ± 6.6	94.49 ± 6.6	82.79 ± 10.5	99.85 ± 0.1	98.62 ± 1.8	95.06 ± 6.8	84.09 ± 10.9
+2	94.74 ± 0.0	87.39 ± 0.0	87.39 ± 0.0	70.55 ± 0.0	99.25 ± 0.0	94.31 ± 0.0	88.21 ± 0.0	73.03 ± 0.0
+5	75.39 ± 0.0	66.82 ± 0.0	66.82 ± 0.0	52.53 ± 0.0	91.78 ± 0.0	80.91 ± 0.0	68.50 ± 0.0	53.82 ± 0.0
−1	94.68 ± 9.3	90.95 ± 13.7	90.95 ± 3.7	77.81 ± 21.3	97.66 ± 4.5	94.89 ± 9.2	91.51 ± 13.8	79.07 ± 21.1
−2	92.84 ± 2.7	85.25 ± 3.6	85.25 ± 3.6	70.20 ± 3.8	98.90 ± 0.9	93.89 ± 1.6	86.48 ± 4.2	71.58 ± 4.1