Figure 4

Comparison of the doses received by OAR between 60-Gy 3D-CRT, 60-Gy IMRT and 72-Gy SIB-IMRT for all patients (P1 to P16). Doses relative to 60-Gy 3D-CRT are drawn in white, grey for 60-Gy IMRT and black for 72-Gy SIB-IMRT. No significant difference is found when considering the maximum dose received by 1% of the optic chiasm (41.63 vs 45.47 and 42.08 Gy, p > 0.088) (Figure 4a). For the brainstem, the maximum dose received by 1% of the organ is significantly lower (57.01 vs 44.30 and 44.00 Gy, p < 0.001) in 60-Gy IMRT and 72-Gy SIB-IMRT (Figure 4b). Histograms of dose-volumes relative to normal brain comparing 60-Gy 3D-CRT (white), 60-Gy IMRT (grey) and 72-Gy SIB-IMRT (balck) are shown on Figure 4c. No significant difference is found when considering the V18 (p > 0.326). 60-Gy IMRT and 72-Gy SIB-IMRT were significantly smaller for V36 and V50 (19 and 20 vs. 23%, p = 0.049,7 and 7 vs. 12%, p < 0.001). No significant differences for V36 and V50 were found between 72-Gy SIB-IMRT and 60-Gy IMRT (p = 0.605).