Table 3.

Dose heterogeneity

Index	PSW (Gy(RBE) or %)	PSWO (Gy(RBE) or %)
HI - whole brain	1.038 ± 0.01	1.031 ± 0.01*
IC - whole brain	0.036 ± 0.01	0.03 ± 0.01*
HI - brainstem	1.064 ± 0.06	1.028 ± 0.05*
IC - brainstem	0.06 ± 0.05	0.026 ± 0.04*

Abbreviations: PSW passive scatter with compensator; PSWO passive scatter without compensator; HI (homogeneity index) = D5/D95; IC (inhomogeneity coefficient) = D5% - D95%/Dmean; Data presented as mean ± standard deviation. *significant vs. PSW (p < 0.05), Student’s t-test with Bonferroni correction for multiple comparisons.