Table 1.

Pearson correlation values (r) and two-tailed p-values correlating the magnitude of anatomy dose errors to three IMRT QA Gamma passing rate performance metrics. Significant p-values (p<0.01) are italicized for emphasis. (Note: The statistically significant correlations have positive r-value (positive slope) indicating that the highest critical dose errors happen at the higher Gamma passing rates.)

IMRT QA criteriaa	Spinal cord D1cc error		Contralateral parotid mean dose error		Ipsilateral parotid mean dose error		Larynx mean dose error		CTV D95 error
	r	p -value	r	p -value	r	p -value	r	p -value	r	p -value
3%∕3 mm	−0.183	0.07	0.328	<0.01	0.523	<0.01	−0.167	0.20	0.604	<0.01
2%∕2 mm	−0.141	0.17	0.118	0.25	0.588	<0.01	−0.134	0.31	0.653	<0.01
1%∕1 mm	−0.130	0.21	0.10	0.33	0.551	<0.01	−0.295	0.022	0.619	<0.01

^aAnalysis criteria method: Global % difference (normalized to max dose), 10% lower threshold, and γ index≤1 as the passing criterion.