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

Table 2

The comparison of simulated and measured penumbra widths (cm) at 0.1, 0.25, and 0.4 cm for three different fields at 10 cm depth. The uncertainties of simulated values were less than or equal to 2% under the condition of k = 2.

FWHM (cm) of three field sizes	Penumbra widths
	Simulated (cm)	Measured (cm)	Diff. (%)
0.1 (4 × 4 cm^2)	0.410	0.649	−36.8
0.25 (4 × 4 cm^2)	0.646	0.649	−0.462
0.4 (4 × 4 cm^2)	0.977	0.649	50.5
0.1 (10 × 10 cm^2)	0.539	0.752	−28.3
0.25 (10 × 10 cm^2)	0.748	0.752	−0.532
0.4 (10 × 10 cm^2)	1.20	0.752	59.6
0.1 (30 × 30 cm^2)	0.551	0.991	−44.4
0.25 (30 × 30 cm^2)	0.990	0.991	−0.101
0.4 (30 × 30 cm^2)	1.25	0.991	26.1