Table 2.

Comparison of dosimetric parameters for patients according to severity of radiation pneumonitis

(a) 50.4 Gy	All patients (n = 86)	Grade 0–1 (n = 76)	Grade 2–5 (n = 10)	P-value (U test)
	Mean ± S.D.	Mean ± S.D.	Mean ± S.D.
MLD (Gy)	12.6 ± 1.5	12.5 ± 1.4	13.4 ± 1.5	0.13
V5 (%)	56.8 ± 5.6	56.0 ± 5.3	62.9 ± 4.9	0.001
V10	41.1 ± 4.9	40.5 ± 4.7	45.5 ± 4.4	0.006
V15	27.2 ± 4.4	26.9 ± 4.3	29.5 ± 5.3	0.17
V20	18.8 ± 3.6	18.8 ± 3.5	19.4 ± 4.5	0.49
V25	15.7 ± 3.2	15.7 ± 3.1	16.2 ± 4.0	0.48
V30	13.6 ± 2.9	13.5 ± 2.8	14.0 ± 3.7	0.52
V35	11.7 ± 2.6	11.6 ± 2.5	12.0 ± 3.3	0.54
V40	9.0 ± 2.3	9.0 ± 2.2	9.3 ± 2.7	0.65
(b) 59.4 Gy	All patients (n = 70)	Grade 0–1 (n = 60)	Grade 2–5 (n = 10)	P-value (U test)
	Mean ± S.D.	Mean ± S.D.	Mean ± S.D.
MLD (Gy)	16.0 ± 1.7	15.8 ± 1.6	17.0 ± 2.1	0.11
V5 (%)	63.0 ± 5.5	62.0 ± 4.8	69.4 ± 4.9	0.001
V10	46.1 ± 4.7	45.3 ± 4.4	50.6 ± 4.6	0.003
V15	39.9 ± 4.5	39.4 ± 4.2	43.2 ± 4.9	0.065
V20	34.3 ± 4.5	33.8 ± 4.1	37.2 ± 5.9	0.075
V25	22.6 ± 4.3	22.4 ± 4.0	23.8 ± 5.8	0.37
V30	16.7 ± 3.7	16.7 ± 3.6	16.9 ± 4.4	0.54
V35	13.9 ± 3.1	13.9 ± 3.0	14.2 ± 3.9	0.54
V40	11.4 ± 2.8	11.3 ± 2.7	11.6 ± 3.3	0.63

MLD = mean lung dose, U test = Mann-Whitney's U test, Vn = the percentage volume of lung receiving at least n Gy of radiation.