原发性肝癌不同弧度容积旋转调强与常规固定野调强剂量学比较  

Dosmetric comparison of volumetric modulated arc therapies of different arcs and seven-beam fixed gantry intensity-modulated radiotherapy for primary liver cancer

作　　者：侯勇[1] 万振法[2] 范医鲁[1] 

机构地区：[1]山东省千佛山医院肿瘤放疗科,山东济南250012 [2]济南市第四人民医院CT室,山东济南250011

出　　处：《中国医学物理学杂志》2015年第5期747-750,共4页Chinese Journal of Medical Physics

摘　　要：目的:比较4种弧度的容积旋转调强放疗(Volumetric modulated arc therapy,VMAT)和常规7野调强放疗(Intensity Modulation Radiated Therapy,IMRT)技术在治疗原发性肝癌的剂量学差异,并分析5种不同的放疗计划设计方案之间的优劣。方法:15例原发性肝癌患者入组,根据增强CT图像勾画靶区,并在同一套图像上进行135°双弧和三弧,360°双弧和单弧,以及7个固定野调强的5种放疗计划方案,患者总的治疗剂量200 c Gy×30次。统计指标包括剂量体积直方图统计和计划靶区体积(Planning Target Volume,PTV)相关的剂量学参数,均匀性指数(Homogeneity Index,HI)、适形度指数(Conformity Index,CI),肝脏的剂量体积参数、机器跳数(Monitor Units,MU)、治疗时间(Treament Time,TT)和计划时间(Plan Time,PT)等,利用SPSS20.0软件对数据进行单因素方差分析,再进行非参数两两比较。结果:5种放疗计划方案的HI,CI,TT和MU分别进行两两比较,P值等于0.025,0.026,0,0,有统计学差异。其中135°三弧计划PTV的HI值最接近0,CI值最接近于1,脊髓的最大剂量Dmax较之其他4种计划低,4种旋转调强计划的MU和TT分别比7野调强计划缩短58.4%、58.8%、68.3%和69%,平均PT分别延长128.7%、192.9%、135.1%和151.6%,5种治疗调强计划的MU和TT有统计学差异(P=0.00)。结论:原发性肝癌的放疗中,旋转调强可以降低MU和TT,但是增加了平均PT,360°单弧计划在减少计划时间和降低MU方面,有较明显的优势。在实际工作中,可以通过选择适当的角度和弧度,降低危及器官的受量。Objective To compare and analyze the characteristics of volumetric modulated arc therapies （VMAT） of four different arcs and seven-beam fixed gantry intensity-modulated radiotherapy （IMRT） for primary liver cancer. Methods Fifteen patients with primary liver center were selected. Based on the planning target volume （PTV） in enhancement CT images, five plans were developed by Eclipse v10 planning system, 1350 double arcs and three arcs, 3600 single are and double arcs VMAT, and seven-beam fixed gantry IMRT. The total treatment dose was 6000 cGy （200 cGy every time, with a total of 30 times）. The PTV related dosmetric parameters were analyzed by dose-volume histograms. Based on the SPSS20.0 Software, the conformity index （CI）, homogeneity index （HI）, dose-volume parameters of liver, monitor unit （MU）, treatment time （S） and planning time （M） were carded out One-way ANOVA. And then the K Independent Samples was applied. Results There were significant differences between IMRT and VMAT in HI, CI, S and MU, with statistically significant differences, （P=0.025, 0.026, 0, 0）. The HI of PTV in 1350 three arcs VMAT was closest to 0, and the CI was closest to 1. And the Dmax of spinal cord in 1350 three ares VMAT was lower than that in the other four plans. Compared with the seven-beam fixed gantry IMRT, MU and S of these four VMAT were reduced 58.4%, 58.8%, 68.3% and 69%, respectively, while the average M was respectively increased 128.7%, 192.9%, 135.1% and 151.6%. There were statistically significant differences among these five plans in MU and S （P=0, 0）. Conclusion In the radiotherapy for primary liver cancer, VMAT can reduce MU and S, but increase M. And 3600 single arc plan has obvious advantages in reducing M and MU. Therefore, the dose to organs at risk can be reduced by selecting appropriate angle and arc.

关 键 词：原发性肝癌 调强放射治疗 旋转调强放射治疗 剂量学 

分 类 号：R815.2[医药卫生—放射医学] R735.7[医药卫生—临床医学]