Abstract: ObjectiveTo investigate the effects of whole-body gamma-knife hypofractionated radiotherapy on pulmonary function in elderly non-small cell lung cancer(NSCLC) patients. MethodsForty-five patients with NSCLC were treated with whole-body gamma-knife hypofractionated radiotherapy.Prescribed radiation doses were 40～52Gy/8-12F(median dose was 48 Gy).Pulmonary function tests(PFTs) were performed before radiotherapy and at 1-,3-,6-months after radiotherapy (RT) respectively. Tests parameters included forced vital capacity(FVC),forced expiratory volume in one second(FEV1),and diffusing capacity of lung for carbon monoxide(DLCO).PFTs were expressed as a percentage of normal values. ResultsThe overall response rate was 93.3%(42/45).The overall 1-year survival rate was 82.2%(37/45).At 1 month after RT, a significant increase was observed for the FEV1%(P<0.05),but no obviously change was seen in the DLCO%.A significant decrease was in pulmonary function was observed at 3 months after RT(P<0.05).The pulmonary function decreased further at 6 months after RT(P<0.05). Conclusion Whole-body gamma-knife hypofractionated radiotherapy is effective for elderly non-small cell lung cancer patients. At the same time, it is harmful for pulmonary function.