目的:探讨左乳腺癌保乳术后全乳腺野中野正向调强放疗（FIF-IMRT）与固定野逆向调强放疗（FFIO-IMRT）剂量分布的差异。方法:选取江苏省肿瘤医院2016年10月至2018年12月早期左乳腺癌保乳术后患者10例，均设计FIF-IMRT与FFIO-IMRT两组放疗计划，乳腺处方剂量为50 Gy，25次，5次/周，2 Gy/次。在计划靶区满足处方剂量前提下，用剂量-体积直方图（DVH）比较两种计划中计划靶体积（PTV）、危及器官、治疗跳数的剂量学差异。结果:PTV方面，两种计划适形指数（CI）差异无统计学意义（n P>0.05）；FIF-IMRT均匀性指数（HI）高于FFIO-IMRT（0.13±0.02比0.10±0.04，n P0.05）；FIF-IMRT Vn 105%及平均放疗剂量（Dn mean）均高于FFIO-IMRT[（37.63±8.85）%比（18.64±5.27）%，（51.81±0.17）Gy比（51.37±0.26）Gy，均n P0.05）；FIF-IMRT Vn 5 Gy、Vn 10 Gy、Dn mean均低于FFIO-IMRT（均n P0.05），FIF-IMRT Vn 5 Gy、Vn 10 Gy均低于FFIO-IMRT（均n P0.05）；FIF-IMRT Vn 5 Gy、Vn 10 Gy、Dn mean均低于FFIO-IMRT（均n P0.05）；FIF-IMRT Vn 5 Gy低于FFIO-IMRT（n P0.05）。治疗总跳数方面，FIF-IMRT低于FFIO-IMRT（255.6±5.6比525.8±86.9，n P 0.05). Uniformity (HI) of FIF-IMRT was higher than that of FFIO-IMRT (0.13±0.02 vs. 0.10±0.04, n P 0.05); V n 105% and the average radiation dose (Dn mean) of FIF-IMRT were higher than that of FFIO-IMRT [(37.63±8.85)% vs. (18.64±5.27)%, (51.81±0.17) Gy vs. (51.37±0.26) Gy, all n P 0.05); V n 5 Gy, Vn 10 Gy, and Dn mean of FIF-IMRT were lower than those of FFIO-IMRT (all n P 0.05); and V n 5 Gy and Vn 10 Gy of FIF-IMRT were lower than those of FFIO-IMRT (all n P 0.05); V n 5 Gy, Vn 10 Gy, Dn mean of FIF-IMRT were lower than those of FFIO-IMRT (all n P 0.05); V n 5 Gy of FIF-IMRT was lower than that of FFIO-IMRT (n P 0.05). The total number of treatment hops of FIF-IMRT was lower than that of FFIO-IMRT (255.6±5.6 vs. 525.8±86.9, n P < 0.01).n Conclusions:Although the uniformity of FIF-IMRT in the target area is slightly worse than that of FFIO-IMRT, and the volume of high-dose area in the target area is bigger than that of FFIO-IMRT, it is still within the controlled range and can meet the requirements of treatment. FIF-IMRT can effectively reduce low-dose radiation in normal tissues. The number of treatment hops of FIF-IMRT is lower than that of conventional FFIO-IMRT, which shortens the single treatment time, reduces the inaccuracy caused by the patient's body position movement in the treatment process, and reduces the machine loss.