Multiple regression analysis of risk factors related to radiation pneumonitis

Table 2 Comparison of lung function and radiotherapy parameters between the two groups (mean ± standard deviation)

Group (n)	FEV1 (%)	DLCO (%)	FEV1/FVC (%)	PTV (mL)	MLD (Gy)	Total number of radiation fields	Vdose (%)	NTCP (%)
Control group (n = 141)	76.89 ± 6.25	71.97 ± 10.03	72.19 ± 7.44	28.26 ± 8.31	35.29 ± 6.57	7.07 ± 2.07	24.54 ± 10.33	42.45 ± 3.60
Study group (n = 93)	70.26 ± 7.50	64.19 ± 9.71	64.45 ± 7.20	38.48 ± 8.27	40.71 ± 5.42	8.00 ± 1.71	36.06 ± 9.95	49.29 ± 4.72
t	7.339	5.918	7.940	9.235	6.599	3.731	8.589	12.540
P	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001	< 0.001

FEV1: Forced expiratory volume in the first second; DLCO: Carbon monoxide diffusion volume; FVC: Forced vital capacity; PTV: Planned target area; MLD: Mean lung dose; Vdose: Percentage of lung tissue in total lung volume; NTCP: Normal tissue complications.