Table 1.

Summary of the differences between the planned and measured MLC positions for test deliveries. The difference is averaged for all infield leaves at all measured EPID image frames during the delivery and is given in the form of an RMS error and mean difference, $\mu \pm 1\text{SD}$. Each field was measured and analyzed three times, measured at monthly intervals. All measurements are stated in mm.

	Test 1		Test 2		Test 3
VMAT Plan	RMS	$\mu \pm 1\text{SD}$	RMS	$\mu \pm 1\text{SD}$	RMS	$\mu \pm 1\text{SD}$
Prostate 1	0.38	$0.06\pm 0.38$	0.39	$0.07\pm 0.38$	0.38	$0.05\pm 0.37$
Prostate 2	0.39	$0.06\pm 0.39$	0.38	$0.05\pm 0.38$	0.40	$0.06\pm 0.39$
Prostate 3	0.37	$0.05\pm 0.37$	0.37	$0.06\pm 0.37$	0.37	$0.06\pm 0.38$
Head Neck 1	0.44	$0.07\pm 0.44$	0.45	$0.06\pm 0.44$	0.45	$0.08\pm 0.45$
Head Neck 2	0.48	$0.03\pm 0.47$	0.47	$0.04\pm 0.47$	0.45	$0.04\pm 0.44$
Head Neck 3	0.55	$0.06\pm 0.54$	0.58	$0.06\pm 0.58$	0.51	$0.06\pm 0.50$