Normal Tissues Dynamic Static 5 levels Static 10 levels Static 20 levels
Spinal cord Dmax 68.8 ± 9.8 70.8 ± 8.6
(0.211)
68.8 ± 10.3
(0.711)
68.9 ± 10.1
(0.883)
Dmean 52.6 ± 7.0 51.7 ± 6.8
(0.02)
51.8 ± 6.8
(0.02)
51.8 ± 6.8
(0.012)
D50 52.4 ±12.6 51.1 ± 12.1
(0.026)
51.7 ± 12.3
(0.016)
51.8 ± 12.4
(0.019)
Brain stem Dmax 75.5 ± 16 75.2 ± 16.9
(0.693)
75.1 ± 16.2
(0.294)
74.9 ± 16.2
(0.046)
Dmean 41.2 ± 8.7 40.1 ± 8.0
(0.053)
40.3 ± 8.1
(0.042)
40.4 ± 8.1
(0.060)
D50 41.2 ±10.8 40.0 ± 9.9
(0.981)
40.2 ± 10.1
(0.047)
40.3 ±10
(0.080)
L parotid Dmax 100.8±2.6 102.9±5.3
(0.179)
100.7±3.6
(0.818)
100.6±2.6
(0.121)
Dmean 66.4±13.5 65.0±13.5
(0.016)
65.3±14
(0.014)
65.3±13.8
(0.041)
D50 69.6±22.2 67.8±21.3
(0.019)
68.2±23.1
(0.022)
68.4±23.1
(0.032)
R parotid Dmax 96.4±8.6 99.6±9.4
(0.029)
97.1±8.9
(0.122)
96.6±8.5
(0.465)
Dmean 64.2±12.3 63.5±13.3
(0.347)
63.6±12.7
(0.163)
63.5±12.5
(0.037)
D50 72.9±20.1 72.5±21.84
(0.684)
72.7±21.1
(0.742)
72.5±20.9
(0.383)
Values are mean (%) ± standard deviation, ( ) - p values, * - Statistically significant
Table 2: Normal tissue dose for dynamic and static IMRT plans for head and neck cancers.