Primary observing pulmonary function variety following three-dimensional conformal radiation therapy of III phase non-small cell lung cancer

Objective To explore the pulmonary function,DVH and radiation pneumonitis after three-dimensional conformal radiation treatment ofⅢphase non-small-cell lung cancer.Methods 71 pa- tients (male 52,female 19,median age 63,KPS≥80) were evaluated by pulmonary function tests before radiotherapy and in M1 and M3 after radiotherapy respectively.After 3 months of follow-up time,it reviewed the appearance and grade of radiation pneumonitis.Then V_(20),V_(30) and MLD were worked out from dose vol- ume histogram.Results All patients completed radiotherapy,and total dose was 66-70 Gy.FVC (L), FEV1 (L) and CLCO were (2.58±0.65) L,(1.85±0.58) L and (15.15±4.65)ml/(min)before radio- therapy,with (2.96±0.76) L,(2.13±0.65) L and (14.71±3.92) ml/(min) in Ml after radiotherapy, with (2.65±0.61) L,(1.92±0.52) L and (13.15±3.71)ml/(min)in M3 after radiotherapy.The ac- cidence of radiation pneumonitis was 30%,moderate and severe radiation pneumonitis was 7%.With V_(20), V_(30) and MLD increasing,the grade of radiation pneumonitis was increasing.V_(20),V_(30) and MLD were related to the change in CLCO value among before,M1 and M3 after radiotherapy,and the correlation coefficient was more than 0.2.Conclusions There is a relationship in the pulmonary function,DVH and radiation pneu- monitis surely.The change in C_LCO value between before radiotherapy and M1 after radiotherapy could pre- dict the radiation pneumonitis.V_(20),V_(30) and MLD are not only correlated to radiation pneumonitis evidently but the change in FEV_1 and C_LCO after radiotherapy.