Table 1. Comparison of Rectal Toxicity with VMAT Alone to VMAT with a Rectal Spacer.

Volumetric modulated arc radiotherapy: VMAT

Dose received by [x%] of rectum	VMAT + spacer	VMAT
1%	60.4 Gy	78.7 Gy
2%	58.5 Gy	78.5 Gy
5%	54.4 Gy	77.1 Gy
10%	49.6 Gy	70.4 Gy
15%	45.90 Gy	62.5 Gy
20%	43.0 Gy	56.5 Gy
25%	40.37 Gy	51.8 Gy
30%	37.2 Gy	46.7 Gy
35%	33.66 Gy	38.9 Gy
40%	30.0 Gy	25 Gy
45%	25.72 Gy	13.7 Gy
50%	20.34 Gy	6.6 Gy