Table 1. Penumbra values in mm for all collimator sizes at 5.0 cm and 10.0 cm depth.

The higher value of the wheel plan and orthoplane penumbra are recorded. Wheel plane is defined as the plane that contains the collimator wheel. The orthoplane is perpendicular to it.

Collimator size	4 mm	5 mm	7.5 mm	10 mm	12.5 mm	15 mm	20 mm	25 mm
Left Penumbra 5 cm	1.77	1.88	1.94	2.00	2.06	2.11	2.19	2.27
Left Penumbra 10 cm	2.00	2.12	2.21	2.29	2.35	2.43	2.54	2.64
Right Penumbra 5 cm	1.78	1.85	1.93	1.99	2.08	2.11	2.19	2.27
Right Penumbra 10 cm	2.02	2.11	2.19	2.28	2.39	2.44	2.53	2.69