摘要
目的:探讨容积旋转调强(VMAT)规避扇区功能在中央型肺癌放疗中降低肺部受量的可行性。方法:选取近期16例中央型肺癌病例,利用规避扇区制作部分弧形照射(P-VMAT)计划,以及全弧VMAT计划和5野均分的调强放射治疗(IMRT)计划。比较靶区的适形度指数、均匀性指数,正常组织比较双肺V_5、V_(20)、V_(30)、平均肺剂量,以及心脏、脊髓和食管受量。评价每种计划执行效率。结果:3种计划均能很好满足临床需要。P-VMAT计划与全弧VMAT计划相比,靶区适形度指数有所下降,其他剂量学指标均无明显变化,双肺受量有所下降,尤其V_5下降明显,其他危及器官无明显差别。P-VMAT计划与IMRT计划相比,靶区剂量学指标有所提高,双肺高剂量区下降明显,V_5指标稍有升高,治疗时间缩短。结论:利用规避扇区制作P-VMAT计划能降低双肺低剂量区域,保留VMAT的其他优点,能够适用于中央型肺癌的放射治疗。
Objective To explore the feasibility of avoiding sector function to reduce the dose to lungs in volumetric modulated arc therapy （VMAT） for central lung cancer. Methods Three plans avoiding sector function were generated for 16 patients with central lung cancer, including partial arc VMAT （P-VMAT） plan, full-arc VMAT plan and 5-field intensity-modulated radiotherapy （IMRT） plan. The conformity index and homogeneity index of the planning target volume, the V5, V20, V30 of lungs, mean lung dose, and the doses to heart, spinal cord and esophagus were compared, and the execution efficiency of plans were evaluated. Results All the 3 plans met the clinical requirement. P-VMAT plan showed a slightly decreased conformity index of target areas and a declined dose to lungs, especially the V5 of lungs, as comparison with full-arc VMAT plan, and no significant differences were found in the other dosimetry indicators of target areas and the dose to the other organs-at-risk. Compared with IMRT plan, P-VMAT plan increased the dosimetry indicators of target areas, significantly decreased the dose to high-dose area of lung but slightly increased the V5 of lungs, and shortened the treatment time. Conclusion P-VMAT plan avoiding sector function which is suitable for the radiotherapy for central lung cancer can reduce the dose to low dose area in lungs and maintain other advantages of VMAT.
出处
《中国医学物理学杂志》
CSCD
2017年第11期1091-1095,共5页
Chinese Journal of Medical Physics
基金
国家自然科学基金(81603475)
关键词
中央型肺癌
容积旋转调强
规避扇区功能
central lung cancer
volumetric modulated arc therapy
avoiding sector function
