Table 4: Brainstem sparing average values ( 1σ) for both collimator systems.

Group

Parameter

m3

MLC-160

p-value

III

(n = 16)

D0.1cm3 (Gy)

12.74 1.55

13.61 1.232

0.015

V ≥ 12Gy (cm3)

0.56 1.03

0.71 0.95

0.003

V ≥ pi (cm3)

0.37 1.04

0.42 0.98

0.065

IV

(n = 14)

D0.1cm3 (Gy)

12.54 1.93

13.14 1.95

0.008

V ≥ 12Gy (cm3)

0.29 0.25

0.53 0.39

< 0.001

V ≥ pi (cm3)

0.08 0.08

0.23 0.20

0.002