Fig. 2.
Logistic regression curves of the predicted probability of radiation pneumonitis of grade 2 or worse (grade 2+ RP) based on (a) mean lung dose (MLD), (b) lung V5Gy, and (c) lung V20Gy. The black circles indicate each patient with grade 2 RP, and the red circles indicate each patient with grade 3 RP. The dotted lines indicate that the 20% and 50% predicted probabilities for grade 2+ RP are 6.1 Gy and 9.1 Gy for MLD, 31.6% and 42.8% for lung V5Gy, and 8.0% and 16.1% for lung V20Gy, respectively. Abbreviations: lung VxGy = the volume of the normal lung receiving ≥x Gy.