Table 4.

Comparison of ArcCHECK patient-specific QA results between dose grid sizes of 1 mm × 1 mm and 2 mm × 2 mm for SBRT plans. The difference is statistically significant if a p value is < 0.05.

	Group C: SBRT DCAT†
Gamma criteria	3%/3 mm		3%/2 mm		2%/2 mm		2%/1 mm
Dose grid size	2 mm	1 mm	2 mm	1 mm	2 mm	1 mm	2 mm	1 mm
Gamma passing rate (mean ± SD) (%)	100	100	99.71 ± 0.40	99.80 ± 0.36	97.22 ± 2.62	97.60 ± 2.41	85.51 ± 9.32	86.39 ± 8.69
Statistically significantly different? (Y/N)	unavailable		N (p value = 0.4375)		Y (p value = 0.0313)		Y (p value = 0.0098)
	Group D: SBRT VMAT‡
Gamma criteria	3%/3 mm		3%/2 mm		2%/2 mm		2%/1 mm
Dose grid size	2 mm	1 mm	2 mm	1 mm	2 mm	1 mm	2 mm	1 mm
Gamma passing rate (mean ± SD) (%)	98.83 ± 3.67	99.82 ± 0.34	97.73 ± 5.88	99.71 ± 0.51	95.96 ± 6.68	99.00 ± 1.17	86.85 ± 13.55	93.60 ± 4.57
Statistically significantly different? (Y/N)	Y (p value <0.0001)		Y (p value <0.0001)		Y (p value <0.0001)		Y (p value <0.0001)

^†Dynamic conformal arc therapy

^‡Volumetric modulated arc therapy