Table 4.
Summary and comparison of the dosimetric parameters of tumors located close to the chest wall (60 CGE/4 fx = 2, 50 CGE/4 fx = 18, 70 CGE/10 fx = 1, and 60 CGE/10 fx = 1).
| OARs | PBT | 3D-CRT | IMRT | VMAT | p-Value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Median | Range | Median | Range | Median | Range | Median | Range | PBT vs.3D-CRT | PBT vs.IMRT | PBT vs.VMAT | ||
| Total lung (n = 22) | ||||||||||||
| V5 (%) | 9.61 | 3.6–14.7 | 14.32 | 6.0–21.6 | 14.12 | 6.0–20.8 | 12.49 | 4.8–20.3 | <0.001 | <0.001 | <0.001 | |
| V10 (%) | 7.53 | 2.8–12.1 | 9.92 | 4.1–15.1 | 9.63 | 4.3–15.0 | 8.98 | 4.0–14.0 | <0.001 | <0.001 | <0.001 | |
| V15 (%) | 6.02 | 2.2–10.0 | 6.94 | 2.7–11.6 | 6.86 | 2.9–11.5 | 6.13 | 3.0–10.6 | 0.001 | 0.009 | 0.222 | |
| V20 (%) | 4.91 | 1.7–8.5 | 4.99 | 2.1–9.0 | 4.88 | 2.1–8.9 | 4.37 | 2.1–8.1 | 0.085 | 0.849 | 0.018 | |
| V30 (%) | 3.12 | 1.2–5.7 | 2.75 | 1.2–5.6 | 2.67 | 0.9–5.2 | 2.52 | 1.0–4.7 | 0.006 | 0.001 | <0.001 | |
| V40 (%) | 1.91 | 0.8–4.0 | 1.76 | 0.7–3.7 | 1.59 | 0.5–3.1 | 1.61 | 0.5–2.9 | <0.001 | <0.001 | <0.001 | |
| Mean dose (Gy) | 2.55 | 0.9–4.2 | 3.54 | 1.7–5.8 | 3.47 | 1.8–5.5 | 3.4 | 1.7–5.3 | <0.001 | <0.001 | <0.001 | |
| Heart (n = 22) | ||||||||||||
| V5 (%) | 0 | 0–1.7 | 2.75 | 0–59.5 | 4.45 | 0–62.26 | 5.19 | 0–56.0 | 0.002 | 0.002 | 0.002 | |
| V10 (%) | 0 | 0–1.2 | 0 | 0–19.9 | 0.04 | 0–21.9 | 0 | 0–18.9 | 0.014 | 0.002 | 0.004 | |
| V15 (%) | 0 | 0–0.8 | 0 | 0–5.1 | 0 | 0–5.8 | 0 | 0–5.7 | 0.181 | 0.181 | 0.059 | |
| V20 (%) | 0 | 0–0.6 | 0 | 0–1.2 | 0 | 0–1.5 | 0 | 0–1.2 | 1 | 0.371 | 1 | |
| V30 (%) | 0 | 0–0.3 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | |
| V40 (%) | 0 | 0–0.1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | |
| Mean dose (Gy) | 0 | 0–0.4 | 1.14 | 0–6.7 | 1.18 | 0–7.1 | 1.28 | 0–6.5 | <0.001 | <0.001 | <0.001 | |
| Dmax (Gy) | 0.02 | 0–63.74 | 8.43 | 0.4–24.9 | 10.68 | 0.4–26.7 | 9.25 | 0–26.1 | <0.001 | <0.001 | <0.001 | |
| Proximal bronchial tree (n = 19) | ||||||||||||
| Dmax (Gy) | 3.69 | 0–38.4 | 9.35 | 0.5–34.0 | 10.8 | 0.5–33.6 | 10.36 | 0.5–36.2 | 0.104 | 0.020 | 0.009 | |
| D1cc (Gy) | 0.62 | 0–21.7 | 4.92 | 0.4–22.3 | 5.77 | 0.4–24.4 | 4.61 | 0.4–24.0 | <0.001 | <0.001 | <0.001 | |
| Spinal cord (n = 22) | ||||||||||||
| Dmax (Gy) | 0 | 0–13.8 | 7.49 | 2.9–23.8 | 7.3 | 2.9–18.1 | 8.66 | 4.1–22.1 | <0.001 | <0.001 | <0.001 | |
| Esophagus (n = 22) | ||||||||||||
| Mean dose (Gy) | 0 | 0–1.4 | 2.3 | 0.5–7.5 | 2.22 | 0.6–8.0 | 2.57 | 0.7–7.6 | <0.001 | <0.001 | <0.001 | |
| Dmax (Gy) | 0.01 | 0–17.5 | 8.27 | 3.8–14.8 | 9.5 | 5.0–17.2 | 10.42 | 5.2–17.8 | <0.001 | <0.001 | <0.001 | |
| Chest wall (n = 22) | ||||||||||||
| Dmax (Gy) | 55.69 | 35.3–74.9 | 60.48 | 34.9–91.2 | 60.59 | 34.5–77.1 | 61.29 | 36.4–77.0 | <0.001 | 0.001 | <0.001 | |
| D30cc (Gy) | 26.79 | 15.5–38.3 | 28.83 | 20.2–38.8 | 27.51 | 18.8–35.7 | 26.93 | 19.8–34.0 | 0.008 | 0.808 | 0.874 | |
| Skin (n = 21) | ||||||||||||
| Dmax (Gy) | 16.24 | 9.8–38.1 | 23.69 | 13.5–39.7 | 24.68 | 16.5–40.5 | 24.69 | 13.2–41.4 | <0.001 | <0.001 | <0.001 | |
OARs, organs at risk; PBT, proton beam therapy; 3D-CRT, three-dimensional conformal radiotherapy; IMRT, intensity-modulated radiotherapy; VMAT, volumetric-modulated arc therapy, CGE, cobalt gray equivalent; fx, fractions; V5–40; percentage volume of tissue receiving 5–40 Gy; Dmax, maximum dose; D1cc, the dose delivered to 1 cubic centimeter volume; D30cc, the dose delivered to 30 cubic centimeter volume.