ABSTRACT
Objective To explore the effects of intensity modulated radiation therapy (IMRT) on lung function in patients with non small cell lung cancer (NSCLC) ,analyze relationship between lung function indexes and radiation pneumonitis (RP) incidence rate ,dose volume histogram (DVH) parameters and incidence degree of RP .Methods 52 patients without operation first radiother‐apy patients were included ,all with Karnofsky score (KPS) ≥ 80 points .Detection of IMRT ,before the end of the end ,first months ,third months of forced vital capacity (FVC) ,forced expiratory volume in one second (FEV1 .0) and diffusion capacity of carbon monoxide (DLCO) change were conducted .The incidence and degree of RP were measured ,and got the V20 and V30 value in DVH .By Spearman correlation analysis ,the relationship between pulmonary function index and the incidence of RP ,V20 ,V30 and RP was analyzed .Results Among the 52 patients ,49 patients were followed up ,the follow -up rate was 94 .2% .In the 49 pa‐tients ,two cases were excluded in the lung recurrence or lung metastasis patients ,thus a total of 47 patients were included in the fi‐nal study .There were 18 cases of RP ,the incidence of RP was 38 .30% .In the third month ,FEV1 .0 and DLCO were significantly decreased than that before radiotherapy (P0 .05) .Correlation analysis showed that FVC ,FEV1 .0 and DLCO and RP were positively correlated (r=0 .451 ,0 .405 ,0 .635 ,P<0 .05);and V20 ,V30 and RP was posi‐tively correlated (r=0 .689 ,0 .725 ,P<0 .05) .Conclusion the larger the NSCLCV20 ,V30 value ,the more serious the RP would be ,thus they could be predictor of RP degree .