摘要
目的:比较容积旋转调强治疗(VMAT)和固定野调强治疗(IMRT)两种技术在乳腺癌根治术后放疗中剂量学的差异。方法:选择10例右侧根治术后乳腺癌放疗的病人,使用Oncentra4.3计划系统,快速容积旋转调强(VMAT)起始角度为55°,结束角度为215°,双弧;固定野调强技术(IMRT)采用六野照射,同一病人两种计划的中心点和优化目标条件均一样。靶区处方为50Gy/25次。评估两种计划靶区的适形度指数和均匀性指数,以及正常器官如患侧肺,正常肺,对侧乳腺,心脏等器官的剂量;机器跳数,治疗时间。结果:VMAT组的靶区均匀性指数(HI)好于IMRT(低29.9%),分别为0.129±0.021,0.184±0.04,P=0.000。适形度指数CI差别不大,差异没有统计学意义。VMAT组的患侧肺,正常肺的V5,V20,以及平均剂量均低于IMRT组。且前者靶区内外的剂量曲线更为接近,低剂量区域的受照面积较IMRT更少,出射总跳数减少了28.5%(P=0.000),治疗时间缩短了80%(P=0.000)。结论:VMAT技术在术后乳腺癌的治疗应用上,相比IMRT技术而言,能够明显降低患侧肺及其他危及器官的受量。同时照射时间,跳数总数也明显低于IMRT,缩短了病人的治疗时间,减小了因时间过长病人移动带来的误差,降低了加速器的损耗率,提高了机器工作效率。
Objective： To compare the dosimetry difference between VMAT（ Volumetric Modulated Arc Therapy） and IMRT（ Intensity Modulated Radiotherapy） for postoperative radiotherapy of breast cancer. Methods：Ten breast cancer patients who accepted modified radical mastectomy on the right side were selected and planned using Oncentra 4. 3 treat-ment planning system. The beginning and ending angles of the VMAT was 55° and 215°,respectively with double arcs. Six fields with equal interval was applied in the fixed field IMRT. The two plans had the same isocenter and optimization condi-tion for the same patient. Targets prescription was set to 50Gy/25f. Planning evaluation included the conformity index（CI） and homogeneity index（ HI） of PTV, dosimetric parameters of organs at risk, monitor units and treatment time. Results：The HI of VMAT was better than that of IMRT（ decreased by 29. 9%） which were 0. 129 ± 0. 021,0. 184 ± 0. 04 respec-tively （P=0. 000）. No significant difference was observed of CI between these two methods. The V5,V20,and mean dose of VMAT group were lower than that of IMRT. In addition, the isodose curve was more compact, smooth, uniform and reg-ular in the VMAT group with less low dose area comparing with that of IMRT. Meantime, the monitor units and treatment time were decreased by 28. 5% and 80% of VMAT in comparison with that of IMRT. Conclusion： Compared to IMRT, VMAT technology can significantly reduce the dose of ipsilateral lung and other organs ar risk in the treatment for postoperative breast cancer patients. At the same time, the VMAT technology can not only decrease the monitor units and treatment time, thus reduce the errors brought by the patient moving, but also can reduce the arrtition rate of accelerator and improve the work efficiency of the machine.
出处
《肿瘤预防与治疗》
2014年第5期226-230,共5页
Journal of Cancer Control And Treatment
基金
四川省科技支撑计划项目
项目编号2014SZ0001
关键词
乳腺癌
容积快速旋转调强
固定野调强
剂量
Breast Cancer
Volumetric Intensity Modulated Arc Therapy（VMAT）
Intensity modulated RadiationTherapy（IMRT）
Dose
