A Mathematical Method to Adjust MLC Leaf End Position for Accurate Dose Calculation in Carbon Ion Beam Radiation Therapy Treatment Planning System

Table 3

The MLC leaf end offset correction and secondary radiation equivalent dose for different materials of 400 MeV/n carbon ion beam at different field sizes.

Field size/2 (cm)	1 cm^2	2 cm^2	3 cm^2	4 cm^2	5 cm^2	6 cm^2	7 cm^2	8 cm^2	9 cm^2	Secondary radiation equivalent dose (10^-4 Sv)
	Offset correction (mm)
W100	-0.05101	-0.12479	-0.19793	-0.27667	-0.34578	-0.36887	-0.43788	-0.50684	-0.57572	4.046 7
W90Cu10	-0.07208	-0.14874	-0.2208	-0.30202	-0.36022	-0.44136	-0.49946	-0.58049	-0.64328	3.8475
W50Cu50	-0.08587	-0.17915	-0.25441	-0.33522	-0.41607	-0.51409	-0.61493	-0.68951	-0.76274	3.613 8
Fe100	-0.10829	-0.21594	-0.32435	-0.43254	-0.54067	-0.65289	-0.7421	-0.8669	-0.9768	2.819 4
Ni100	-0.09836	-0.1921	-0.29042	-0.3864	-0.48112	-0.57674	-0.67966	-0.76811	-0.86531	2.696 4
Cu100	-0.10312	-0.19007	-0.299	-0.39392	-0.50628	-0.61128	-0.71152	-0.79512	-0.89624	2.971 6
Cu59Zn41(H59)	-0.10505	-0.21154	-0.31712	-0.41582	-0.5155	-0.6313	-0.7299	-0.84279	-0.94332	2.935 2
FeCrNiMn(SS304)	-0.10681	-0.21337	-0.3227	-0.42765	-0.53213	-0.62525	-0.73477	-0.84632	-0.95621	2.823 1
Al100	-0.25469	-0.51498	-0.77095	-1.02784	-1.28281	-1.54666	-1.79796	-2.06729	-2.31803	2.553 8