基于计划质量度量（PQM）量化比较有无均整器模式下肝癌容积旋转调强放疗计划  

Quantitative comparison of volumetric-modulated arc therapy plans for liver cancer using flattening filter-free and flattening filter modes based on plan quality metric （PQM）

作　　者：夏文龙 陈波 黄鹏 戴建荣 Xia Wenlong;Chen Bo;Huang Peng;Dai Jianrong(Department of Radiation Oncology,National Cancer Center/National Clinical Research Center for Cancer/ Cancer Hospital,Chinese Academy of Medical Sciences and Peking Union Medical College,Beijing 100021,China)

机构地区：[1]国家癌症中心、国家肿瘤临床医学研究中心、中国医学科学院北京协和医学院肿瘤医院放疗科,北京100021

出　　处：《中华放射医学与防护杂志》2018年第9期680-683,共4页Chinese Journal of Radiological Medicine and Protection

基　　金：国家重大研发计划项目（2016YFC0904600）

摘　　要：目的 通过建立计划质量度量（PQM）量化评估肝癌放疗计划中常规分割的容积旋转调强放疗（VMAT）在有无均整器模式下的计划质量。方法 选取10例肝癌患者，分别在6 MV X射线的传统均整器（FF）模式和无均整器（FFF）模式下进行计划设计，评价靶区（PTV）和危及器官（OAR）的剂量分布，比较两种模式下加速器的机器跳数和出束时间。根据临床的限量要求定义具有16个评价对象的计划质量度量来评估两种模式下的计划质量。结果 FFF模式下，靶区最大剂量小于FF模式（t=3.828，P〈0.05），正常肝组织的超过5 Gy归一化体积（V5）和平均剂量（Dmean）低于FF模式（t=2.716、3.007，P〈0.05）。FFF模式的平均机器跳数（574±130）MU比FF模式（518±81）MU高（t=-2.782，P〈0.05），而平均出束时间（108±36）s相比FF模式（160±29）s明显降低（t=6.767，P〈0.05）。FFF模式的整体PQM评分值高于FF模式（t=-2.746，P〈0.05）。结论 FFF模式能够更好的保护危及器官的低剂量区域。FFF模式的机器跳数高，但是出束时间明显低于FF模式。参照PQM评估标准，FFF模式的整体计划质量略高。Objective To quantitatively assess the plan quality of conventional fractionated volumetric modulated arc therapy （VMAT） plans for liver cancer treatments using flattening filter-free （FFF） and flattening filter （FF） modes based on plan quality metric （PQM）. Methods A total of ten patients with liver tumor were selected. The patients were planned in FF and FFF mode of 6 MV X-ray respectively. The dose distribution of the planning target volume （PTV） and the organ at risk （OAR） were evaluated, and the monitor units （MUs） and the beam on time （BoT） were compared. According to the clinical requirements, a PQM with 16 submetrics was defined to evaluate the plan quality of the two modes. Results The maximal dose of FFF plan was less than that of FF plan （t=3.828, P〈0.05）. The normalized volume of 5 Gy （V5） and mean dose （Dmean） of the normal liver of FFF plan were lower than those of the FF plan （t=2.716, 3.007, P〈0.05）. The average MU of FFF plan[（574±130） MU] was higher than that of FF plan[（518±81） MU]（t=-2.782,P〈0.05）, while the average BoT of FFF plan[（108±36）s] was significantly lower than that of FF plan[（160±29） s]（t=6.767,P〈0.05）. The score of FFF plan was higher than that of FF plan （t=-2.746, P〈0.05）. Conclusions FFF mode can better protect the OAR at low dose levels. The MU of FFF mode plan were higher, but the beam on time was significantly lower than FF mode plan. With reference to the PQM evaluation criteria, the overall plan quality of the FFF mode was slightly higher.

关 键 词：计划质量度量 无均整器模式 肝癌 容积旋转调强放疗 剂量学 

分 类 号：R730.55[医药卫生—肿瘤] R735.7[医药卫生—临床医学]