Fig. 2.

Dose–volume histograms for internal target volume (ITV) (A), planning target volume (PTV) (B), normal lung ( = lung minus internal target volume) (C), and chest wall (D), for the same patient as shown in Fig. 1. Mean PTV doses of the 60 Gy/5 fractions − (60% isodose) regimen and 50 Gy/5 fractions − (80% isodose) regimen were 93.7 Gy and 60.4 Gy, respectively. For the two regimens, the mean ITV was 80.5 Gy and 57.1 Gy, respectively, the volume irradiated > 20 Gy (V₂₀) in the normal lung was 6.8% and 6.5%, respectively, and the V₃₀ in the chest wall was 46.4 ml and 41.0 ml, respectively.