Yin Yong, Chen Jinhu, Sun Tao, Ma Changsheng, Lu Jie, Liu Tonghai, Wang Ruozheng
School of Information Science and Engineering, Shandong University, Ji'nan, China.
Med Dosim. 2012 Autumn;37(3):287-92. doi: 10.1016/j.meddos.2011.11.001. Epub 2012 Jan 28.
Intensity-modulated radiotherapy (IMRT) has played an important role in breast cancer radiotherapy after breast-preservation surgery. Our aim was to study the dosimetric and implementation features/feasibility between IMRT and intensity-modulated arc radiotherapy (Varian RapidArc, Varian, Palo Alto, CA). The forward IMRT plan (f-IMRT), the inverse IMRT, and the RapidArc plan (RA) were generated for 10 patients. Afterward, we compared the target dose distribution of the 3 plans, radiation dose on organs at risk, monitor units, and treatment time. All 3 plans met clinical requirements, with RA performing best in target conformity. In target homogeneity, there was no statistical significance between RA and IMRT, but both of homogeneity were less than f-IMRT's. With regard to the V(5) and V(10) of the left lung, those in RA were higher than in f-IMRT but were lower than in IMRT; for V(20) and V(30), the lowest was observed in RA; and in the V(5) and V(10) of the right lung, as well as the mean dose in normal-side breast and right lung, there was no statistically significance difference between RA and IMRT, and the lowest value was observed in f-IMRT. As for the maximum dose in the normal-side breast, the lowest value was observed in RA. Regarding monitor units (MUs), those in RA were higher than in f-IMRT but were lower than in IMRT. Treatment time of RA was 84.6% and 88.23% shorter than f-IMRT and IMRT, respectively, on average. Compared with f-IMRT and IMRT, RA performed better in target conformity and can reduce high-dose volume in the heart and left lung-which are related to complications-significantly shortening treatment time as well. Compared with IMRT, RA can also significantly reduce low-dose volume and MUs of the afflicted lung.
调强放疗（IMRT）在保乳手术后的乳腺癌放疗中发挥了重要作用。我们的目的是研究IMRT与容积调强弧形放疗（瓦里安快速弧形放疗，瓦里安公司，加利福尼亚州帕洛阿尔托）之间的剂量学及实施特点/可行性。为10例患者生成了正向IMRT计划（f-IMRT）、逆向IMRT和快速弧形放疗计划（RA）。随后，我们比较了这3种计划的靶区剂量分布、危及器官的辐射剂量、监测单位和治疗时间。所有3种计划均符合临床要求，其中RA在靶区适形性方面表现最佳。在靶区均匀性方面，RA与IMRT之间无统计学差异，但两者的均匀性均低于f-IMRT。关于左肺的V(5)和V(10)，RA中的值高于f-IMRT，但低于IMRT；对于V(20)和V(30)，RA中观察到的值最低；在右肺的V(5)和V(10)以及患侧乳腺和右肺的平均剂量方面，RA与IMRT之间无统计学差异，f-IMRT中观察到的值最低。至于患侧乳腺的最大剂量，RA中观察到的值最低。关于监测单位（MUs），RA中的值高于f-IMRT，但低于IMRT。RA的治疗时间平均分别比f-IMRT和IMRT短84.6%和88.23%。与f-IMRT和IMRT相比，RA在靶区适形性方面表现更好，并且可以显著减少与并发症相关的心脏和左肺的高剂量体积，同时也显著缩短了治疗时间。与IMRT相比，RA还可以显著减少患侧肺的低剂量体积和MUs。
