Table 2. Dose statistics for clinical, HSRT, and BSRT treatment plans for all 8 NPT cases.
| Dose Statistic | Standard Clinical | HSRT | BSRT | p-value | |||||
|---|---|---|---|---|---|---|---|---|---|
| Mean | Range | Mean | Range | Mean | Range | Clinical vs HSRT | Clinical vs BSRT | HSRT vs BSRT | |
| PTV | |||||||||
| Conformity Index (CI) | 0.77 | 0.70–0.84 | 0.78 | 0.72–0.84 | 0.75 | 0.70–0.80 | 0.613 | 0.310 | 0.127 |
| Homogeneity Index (HI) | 0.12 | 0.08–0.23 | 0.14 | 0.10–0.24 | 0.14 | 0.11–0.24 | 0.467 | 0.436 | 0.975 |
| PTV1 edited D95% (Gy) | 61.5 | 57.0–62.6 | 61.0 | 56.7–62.3 | 61.0 | 56.9–62.0 | 0.051 | 0.001 | 0.839 |
| Hippocampi | |||||||||
| Bilateral hippocampus max (Gy) | 43.6 | 15.5–62.4 | 27.1 | 10.1–45.6 | 33.7 | 8.6–59.9 | 0.001 | 0.026 | 0.169 |
| Bilateral hippocampus mean EQD2 (Gy) | 21.5 | 13.3–32.0 | 8.4 | 4.3–23.2 | 8.7 | 3.6–17.2 | 0.001 | 0.001 | 0.939 |
| Bilateral hippocampus D40% EQD2 (Gy) | 23.5 | 14.5–35.0 | 8.6 | 4.2–24.7 | 9.0 | 4.3–17.3 | 0.001 | <0.001 | 0.865 |
| Probability of NCF impairment | 0.73 | 0.42–0.98 | 0.24 | 0.10–0.89 | 0.24 | 0.08–0.62 | 0.001 | <0.001 | 0.944 |
| Other Brain Structures | |||||||||
| Whole brain mean (Gy) | 12.6 | 9.3–16.8 | 10.4 | 8.2–15.1 | 9.3 | 5.6–14.1 | 0.006 | <0.001 | 0.012 |
| Whole brain max (Gy) | 63.6 | 58.4–69.3 | 62.8 | 57.5–70.3 | 63.6 | 59.2–69.4 | 0.179 | 1.000 | 0.147 |
| Cerebellum mean (Gy) | 34.1 | 26.3–39.8 | 29.2 | 24.7–37.0 | 28.3 | 17.8–36.1 | 0.033 | 0.037 | 0.720 |
| Cerebellum V20Gy (%) | 93.6 | 76.9–98.9 | 82.5 | 64.7–94.4 | 74.9 | 37.6–97.7 | 0.026 | 0.011 | 0.284 |
| Cerebellum max (Gy) | 58.3 | 52.4–65.1 | 55.7 | 49.7–60.4 | 57.7 | 51.9–66.2 | 0.041 | 0.585 | 0.282 |
| Brainstem max (Gy) | 49.7 | 48.0–51.6 | 49.1 | 46.7–51.8 | 50.4 | 49.0–52.1 | 0.268 | 0.110 | 0.070 |
| Brainstem mean (Gy) | 36.1 | 27.3–42.4 | 32.3 | 28.5–35.9 | 29.6 | 20.9–34.1 | 0.011 | 0.001 | 0.055 |
| Brainstem V20Gy (%) | 91.8 | 67.5–100.0 | 89.5 | 74.3–97.9 | 75.1 | 44.0–96.1 | 0.172 | <0.001 | 0.004 |
| Left cochlear mean (Gy) | 49.4 | 37.5–65.5 | 43.4 | 28.7–66.4 | 41.7 | 21.0–65.2 | 0.010 | 0.048 | 0.394 |
| Right cochlear mean (Gy) | 54.1 | 36.4–65.4 | 48.3 | 32.2–65.5 | 45.2 | 25.8–66.2 | 0.035 | 0.024 | 0.201 |
| Left temporal lobe mean (Gy) | 24.4 | 18.6–34.9 | 20.1 | 13.7–33.1 | 20.5 | 12.9–29.4 | 0.012 | 0.019 | 0.715 |
| Right temporal lobe mean (Gy) | 27.0 | 19.2–36.6 | 21.3 | 14.7–34.0 | 19.2 | 9.3–31.4 | 0.003 | 0.002 | 0.057 |
| Bilateral temporal lobe max (Gy) | 63.0 | 56.3–69.2 | 62.4 | 56.6–70.2 | 62.0 | 54.8–69.0 | 0.376 | 0.342 | 0.637 |
| Optic chiasm max (Gy) | 44.8 | 34.6–53.4 | 43.7 | 32.7–54.0 | 42.0 | 30.4–54.0 | 0.529 | 0.332 | 0.563 |
| Left optic nerve max (Gy) | 37.4 | 10.6–52.8 | 36.7 | 12.3–54.0 | 37.8 | 15.6–54.4 | 0.782 | 0.829 | 0.617 |
| Right optic nerve max (Gy) | 37.8 | 14.0–52.9 | 38.4 | 15.0–55.0 | 35.5 | 12.7–50.6 | 0.663 | 0.270 | 0.162 |
| Other OARs | |||||||||
| Right parotid mean (Gy) | 39.3 | 31.3–48.7 | 39.4 | 32.9–50.5 | 41.6 | 32.0–53.5 | 0.926 | 0.022 | 0.123 |
| Left parotid mean (Gy) | 36.3 | 27.9–45.6 | 35.4 | 27.4–45.6 | 38.2 | 29.0–51.0 | 0.097 | 0.066 | 0.012 |
| Superficial parotids mean (Gy) | 29.0 | 20.8–34.6 | 29.0 | 20.4–34.7 | 32.3 | 20.9–40.0 | 0.981 | 0.011 | 0.024 |
| Mandible mean (Gy) | 45.6 | 41.9–51.4 | 43.6 | 40.6–47.8 | 43.6 | 40.3–48.2 | 0.049 | 0.065 | 0.990 |
| Left lens mean (Gy) | 4.5 | 3.0–8.8 | 4.1 | 2.9–8.4 | 5.0 | 3.0–10.6 | 0.100 | 0.133 | 0.014 |
| Right lens mean (Gy) | 5.4 | 2.8–10.8 | 4.6 | 2.7–10.6 | 5.3 | 2.8–10.5 | 0.126 | 0.943 | 0.026 |
| Cochlear PRV max dose (Gy) | 59.5 | 47.1–68.3 | 57.3 | 46.7–68.5 | 56.0 | 46.8–69.0 | 0.050 | 0.074 | 0.301 |
Statistically significant results (p < 0.05) are highlighted in bold. Doses are in absolute dose, except those stated for the bilateral hippocampus, that are EQD2 assuming α/β = 2 Gy. The probability of NCF impairment was calculated using the NTCP model of Gondi et al., (2013) [13].