Table 4.
The average EUD and NTCP values for optic nerves, optic chiasm, brainstem and brain
| Organ at risk Structure | EUD and NTCP | nc-IMRTa | nc-VMATb | Hybrid IMRT/VMATc | Pairwise comparison P value |
|---|---|---|---|---|---|
| I/L optic nerve | EUD (Gy) | 44.06 ± 4.96 | 44.91 ± 3.69 | 42.23 ± 5.48 | b versus c (0.015*) a versus c (0.042*) |
| NTCPLogit (%) | 1.63 ± 1.72 | 1.66 ± 1.45 | 1.24 ± 1.52 | b versus c (0.021*) a versus c (0.029*) | |
| NTCPLKB (%) | 0.07 ± 0.12 | 0.09 ± 0.10 | 0.05 ± 0.08 | NS† | |
| C/L optic nerve | EUD (Gy) | 39.56 ± 5.99 | 39.90 ± 9.29 | 37.08 ± 9.18 | b versus c (0.034*) a versus c (0.021*) |
| NTCPLogit (%) | 0.63 ± 0.78 | 0.91 ± 1.11 | 0.60 ± 0.98 | b versus c (0.032*) | |
| NTCPLKB (%) | 0.01 ± 0.02 | 0.03 ± 0.09 | 0.02 ± 0.07 | NS† | |
| Optic chiasm | EUD (Gy) | 24.42 ± 9.70 | 21.35 ± 10.42 | 23.04 ± 8.89 | a versus b (0.041*) |
| NTCPLogit (%) | 0.04 + 0.08 | 0.02 ± 0.03 | 0.03 ± 0.10 | NS† | |
| NTCPLKB (%) | 0.003 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | NS† | |
| Brainstem | EUD (Gy) | 3.98 ± 4.58 | 4.67 + 5.51 | 4.14 ± 4.56 | NS† |
| NTCPLogit (%) | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | NS† | |
| NTCPLKB (%) | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | NS† | |
| Brain | EUD (Gy) | 26.51 ± 5.08 | 25.52 ± 3.71 | 24.99 ± 3.74 | NS† |
| NTCPLogit (%) | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | NS† | |
| NTCPLKB (%) | 0.00 ± 0.00 | 0.00 ± 0.00 | 0.00 ± 0.00 | NS† |
nc-IMRT = non-coplanar IMRT; nc-VMAT = non-coplanar VMAT; NTCP = normal tissue complication probability; EUD = equivalent uniform dose; LKB = Lyman–Kutcher–Burman model; I/L = ipsilateral; C/L = contralateral; NS = non-significant.
*Significant (P < 0.05).
† P > 0.01.