Table 1. Dose conformity for permutations of plan parameters.

Plans were generated from permutations of physical objectives for each prescription sub-volume modifying various plan parameters. Bolded values represent default plan parameters. Pitches equivalent to 0.860 divided by an integer were used in this study to minimize the thread effect [17].

	Parameter	Definition	Value	Q0.95–1.05 (% PTV)
Prescription	Levels	Number of dose levels into which voxel-based prescription was discretized	3	69
			5	87
			7	92
			9	93
			11	93
Physical Delivery	Jaw	Longitudinal slice thickness projected at the machine isocenter	5.00 cm	81
			2.50 cm	87
			1.05 cm	93
	Pitch	Ratio of couch travel distance per rotation to the primary jaw width	0.860	91
			0.430	93
			0.287	93
			0.215	93
			0.172	93
	Modulation Factor	Ratio of the maximum leaf opening time to the average leaf opening time for all non- zero leaves	1	36
			1.5	90
			2	92
			3	93
			6	93
Optimization	DVH Volume Objective	Percentage of target substructure receiving prescribed dose or higher	25 %	91
			75 %	89
			VMean Dose	93
	Normalization Point	Scaling factor to normalize dose to primary target objective	Lowest Level	90
			Mean Dose	93
			Highest Level	92