The Study of Dosimetric Characteristics of the XHA600D Medical Linear Accelerator Based on a Monte Carlo Code

Table 5

The simulated and measured profiles of penumbras (cm) of FF and FFF beams for different fields at 10 cm depth (The uncertainties of simulated penumbras in FF mode of 4 × 4, 6 × 6, 8 × 8, 10 × 10, 15 × 15, 20 × 20, 25 × 25, 30 × 30 cm² fields were as follows: 0.4%, 0.8%, 0.6%, 0.8%, 1.2%, 1.6%, 1.8%, 2% (k = 2). The uncertainties of simulated penumbras in FFF mode of 4 × 4, 6 × 6, 8 × 8, 10 × 10, 15 × 15, 20 × 20, 25 × 25, 30 × 30 cm² fields were as follows: 0.8%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6% (k = 2)).

Field size (cm^2)	FF			FFF
	Simulated (cm)	Measured (cm)	Diff. (%)	Simulated (cm)	Measured (cm)	Diff. (%)
4 × 4	0.646	0.649	−0.462	0.639	0.645	−0.930
6 × 6	0.676	0.673	0.446	0.657	0.672	−2.23
8 × 8	0.711	0.716	−0.698	0.702	0.711	−1.27
10 × 10	0.748	0.752	−0.532	0.741	0.752	−1.46
15 × 15	0.812	0.808	0.495	0.795	0.804	−1.12
20 × 20	0.853	0.867	−1.61	0.845	0.866	−2.42
25 × 25	0.874	0.913	−4.27	0.873	0.902	−3.22
30 × 30	0.990	0.991	−0.100	0.940	0.958	−1.88