Table 1.

Heart and lung dose constraints and dose-volume histogram parameters for proton radiation therapy (N = 17).

Structure	Planning goal	Median (range)
Lung
Mean lung dose	≤ 20 Gy	6.5 GyRBE (1.8–9.7)
Lung V5, %	≤ 50	29.3 (8.0–42.2)
Lung V10, %	≤ 40	21.2 (6.3–34.9)
Lung V20, %	≤ 25	10.9 (3.3–24.2)
Heart
Mean heart dose	≤ 26 Gy	7.8 GyRBE (1.0–18.0)
Heart V40, %	≤ 50	7.4 (0–23.0)
Heart V5, %	≤ 65	24.1 (4.4–74.0)

Abbreviations: Lung V5, volume of normal lung receiving 5 Gy; Lung V10, volume of normal lung receiving 10 Gy; Lung V20, volume of normal lung receiving 20 Gy; Heart V40, volume of normal heart receiving 40 Gy; Heart V5, volume of normal heart receiving 5 Gy.