Table 5.
Organs at risk for 6 patients in the 45-patient VMAT cohort with both IMRT and VMAT plans
| Median (Range) | |||
|---|---|---|---|
| IMRT | VMAT | P* | |
| Braina | |||
| Dmean (Gy) | 27.3 (25.8–38.9) | 26.1 (25.1–35.6) | 0.03 |
| Dmax (Gy) | 63.6 (63.1–65.8) | 63.5 (63.1–64.7) | 0.75 |
| V30Gy (%) | 36.6 (32.2–61.1) | 34.8 (32.0–61.5) | 0.60 |
| V60Gy (%) | 4.7 (2.4–7.4) | 4.0 (1.8–6.9) | 0.03 |
| Brainb | |||
| GI50Gy | 1.8 (1.7–2.0) | 1.9 (1.7–2.1) | 0.12 |
| GI60Gy | 6.3 (3.3–8.2) | 7.2 (3.2–8.8) | 0.05 |
| Brainstem | |||
| Dmean (Gy) | 24.3 (16.9–33.8) | 14.1 (9.5–27.2) | 0.03 |
| Dmax (Gy) | 53.8 (51.2–59.4) | 53.5 (49.5–59.9) | 0.12 |
| V30Gy (%) | 27.0 (15.3–56.2) | 19.3 (10.2–45.0) | 0.03 |
| Ipsilateral Hippocampus | |||
| Dmean (Gy) | 45.5 (33.8–58.9) | 41.7 (35.4–58.7) | 0.07 |
| Dmax (Gy) | 56.2 (50.6–63.0) | 56.5 (51.4–63.3) | 0.25 |
| D100% (Gy) | 26.5 (12.1–52.8) | 10.0 (8.4–51.1) | 0.03 |
| Contralateral Hippocampus | |||
| Dmean (Gy) | 21.0 (15.8–45.4) | 23.7 (15.1–42.0) | 0.25 |
| Dmax (Gy) | 44.6 (32.8–62.2) | 44.5 (31.7–62.2) | 0.12 |
| D100% (Gy) | 14.4 (2.5–26.0) | 9.8 (3.9–20.8) | 0.25 |
| Bilateral Hippocampus | |||
| Dmean (Gy) | 35.9 (24.6–45.8) | 33.7 (25.0–42.1) | 0.25 |
| Dmax (Gy) | 56.6 (50.6–63.0) | 56.5 (51.4–63.3) | 0.35 |
| D100% (Gy) | 14.4 (2.5–26.0) | 9.8 (3.9–20.8) | 0.25 |
| Optic Chiasm | |||
| Dmean (Gy) | 37.2 (19.6–50.5) | 36.9 (19.9–52.3) | 0.35 |
| Dmax (Gy) | 50.0 (30.7–55.7) | 52.0 (25.0–53.9) | 0.35 |
| Ipsilateral Optic Nerve | |||
| Dmean (Gy) | 11.7 (4.5–39.9) | 18.9 (7.8–38.1) | 0.35 |
| Dmax (Gy) | 33.6 (14.2–55.1) | 34.1 (15.4–53.9) | 0.60 |
| Contralateral Optic Nerve | |||
| Dmean (Gy) | 9.3 (6.7–29.6) | 13.8 (7.5–31.0) | 0.05 |
| Dmax (Gy) | 23.5 (10.3–54.5) | 25.9 (12.1–52.7) | 0.92 |
| Ipsilateral Cochlea | |||
| Dmean (Gy) | 19.3 (6.2–26.3) | 2.1 (1.4–5.8) | 0.03 |
| Dmax (Gy) | 21.0 (8.4–28.6) | 2.4 (1.5–10.3) | 0.03 |
| Contralateral Cochlea | |||
| Dmean (Gy) | 8.9 (1.4–23.5) | 1.9 (1.4–2.3) | 0.03 |
| Dmax (Gy) | 10.2 (1.5–24.2) | 2.3 (1.5–3.0) | 0.03 |
| Ipsilateral Eye | |||
| Dmean (Gy) | 3.5 (0.8–11.8) | 6.1 (2.8–10.9) | 0.25 |
| Dmax (Gy) | 13.5 (1.5–50.6) | 15.7 (4.7–34.7) | 0.92 |
| Contralateral Eye | |||
| Dmean (Gy) | 4.7 (1.6–5.6) | 4.9 (3.3–8.6) | 0.17 |
| Dmax (Gy) | 8.6 (2.6–41.5) | 11.0 (6.4–34.1) | 0.60 |
| Ipsilateral Lens | |||
| Dmean (Gy) | 2.4 (0.5–6.0) | 2.8 (1.9–4.0) | 0.75 |
| Dmax (Gy) | 2.8 (0.6–7.8) | 3.3 (2.3–4.9) | 0.92 |
| Contralateral Lens | |||
| Dmean (Gy) | 2.3 (1.1–3.6) | 2.6 (2.0–3.9) | 0.35 |
| Dmax (Gy) | 3.4 (1.3–3.9) | 2.9 (2.2–4.8) | 0.75 |
IMRT intensity modulated radiation therapy, VMAT volumetric arc therapy, D min minimum dose, D mean mean dose, D max maximum dose, D100% maximum dose covering 100% of organ, V XXGy volume receiving XX Gy or more, GI gradient index
*From Wilcoxon signed rank sum analysis aBrain organ at risk volume excludes the gross tumor volume, brainstem and optic chiasm volumes bBrain volume does not exclude the gross tumor volume, brainstem and optic chiasm volumes