3D-CRT、IMRT和RapidArc行小细胞肺癌全脑预防性照射的剂量学比较.docVIP

3D-CRT、IMRT和RapidArc行小细胞肺癌全脑预防性照射的剂量学比较 【摘要】 目的 比较小细胞肺癌（SCLC）全脑预防性照射（PCI）3D-CRT、IMRT、RapidArc三种计划方式的剂量学差异，为制定最佳PCI放疗方案提供指导。方法 选取10例SCLC患者颅脑CT，分别设计3D-CRT、IMRT及RapidArc 3种放疗计划行PCI。根据剂量体积直方图，评价靶区的D2%、D98%、V95%、V100%、均匀性指数（HI）、适形性指数（CI）以及危及器官（OAR）受量；比较机器跳数（MU）的差异。 结果 IMRT及RapidArc的靶区剂量学参数（CI、HI、D2%、D98%、V95%、V100%、）均优于3D-CRT，差异均具有统计学意义（P﹤0.05）。IMRT及RapidArc较3D-CRT显著降低双侧视神经、腮腺及脑干的受量，差异均具有统计学意义（P﹤0.05）；相反，3D-CRT能显著减少双侧晶体及眼球的受量，差异均具有统计学意义（P﹤0.05）。IMRT及RapidArc在靶区和危及器官受量方面均无显著性差异（P 0.05）。3D-CRT、IMRT和RapidArc计划的平均MU分别为287.80、1388.80和346.60。 结论 IMRT及RapidArc较3D-CRT进行PCI具有一定的剂量学优势。但3D-CRT能减少晶体及眼球的受量，并且治疗时间短。 [关键词] 三维适形放疗；调强放疗；全脑预防性照射；剂量学 Dosimetric comparison of there-dimensional conformal radiotherapy, intensity-modulated radiotherapy and RapidArc for prophylactic cranial irradiation in small cell lung cancer patients [Abstract] Objective The purpose of this study is to compare the characteristics of there-dimensional conformal radiotherapy (3D-CRT), fixed-field intensity-modulated radiotherapy (IMRT) and RapidArc for prophylactic carnial irradiation (PCI) in small cell lung cancer (SCLC) patients. Methods Ten patients with SCLC were enrolled into this study. 3D-CRT，9-field IMRT (IMRT) and double arc RapidArc plans were generated and optimized for each patient. The goal was to deliver 25Gy to ≥ 95% of the planning target volume (PTV) while meeting the same normal-tissue dose constraints. The dose distribution and conformal index (CI), homogeneity index (HI) of target volume, the maximum dose (D2%), the minimum dose (D98%), target coverage of PTV (V95% and V100%), and Dmean and Dmax of organs at risk (OAR) were analyzed by using the dose volume histogram (DVH). The monitor units and delivery time were also evaluated. Results All plans met the clinical requirements. PTV dosimetry parameters （CI, HI, D2%, D98%, V95% and V100% ）of RapidArc and IMRT were superior to 3D-CRT with significant difference (P﹤0.05). The doses to the optic nerves, parotid glands and brainstem o