This study is to evaluate the effects of recruitment maneuvers on the irradiated volume and absorbed doses during the intensity-modulated radiation therapy (IMRT) with elderly patients with non-small cell lung cancer (NSCLC). 15 elderly patients suffered fromⅡ–Ⅳ class NSCLC with atelectasis were selected for this study. Based on the result of CT images before (CT1) and after irradiation with 32 Gy (CT2), each patient was given 2 IMRT plans (P60 and P32+P28). The changes of target and normal organs were evaluated again. The results showed that the average volumes of CT2-GTV and CT2-PTV were significantly lower than those of CT2-GTV and CT1-PTV, but the volume of CT2-Lungsuffered lung was increased significantly than that of CT1-Lungsuffered lung (p<0.05). The absorbed doses index of other normal organs showed significant differences between two plans (p<0.05). According to the atelectasis in elderly patients with NSCLC, it is necessary to make the CT scan again and design a new IMRT plan after irradiation with 32 Gy, which makes the lung and heart of elderly patients with NSCLC get lower radiation burden after recruitment maneuvers.Cited