Abstract: 【Abstract】Objective To compare the effects of 6MV and 10MV X-ray intensity modulated radiotherapy (IMRT) on non-small-cell lung cancer (NSCLC)Methods 6MV and 10MV X-ray IMRT plans were performed on 8 patients with NSCLC. The doses of the two identical planning objectives of IMRT were calculated by convolution/superposition algorithm provided by ADAC treatment planning system. Plans were compared according to dose-volume histogram (DVH) analysis，including conformity and homogeneity indices (CI and HI). Results Between 6MV and 10MV X-ray plan，the differences of the average garget dose，HI and CI were not statistically significant (P＞0.05)，but the degree of target coverage in high dose of 6MV plan was better than that in 10MV plan. Conclusions 6MV X-ray plan may be the better choice of radiotherapy on NSCLC.

Key words: 【Key words】Intensity modulated radiotherapy, Non-small-cell lung cancer, Dose homogeneity, Conformity index