保乳术后仰卧位与俯卧位部分乳腺外照射靶区体积及剂量学比较  

A comparison of the target volume and dosimetric variance between supine and prone positions for external-beam partial breast irradiation after breast-conserving surgery

作　　者：于婷 王玮 徐敏 孙涛 邵倩 张英杰 刘希军 李奉祥 李建彬 

机构地区：[1]济南大学 山东省医学科学院医学与生命科学学院,250022 [2]山东大学附属山东省肿瘤医院放疗科,济南250117 [3]山东大学附属山东省肿瘤医院物理室,济南250117

出　　处：《中华放射医学与防护杂志》2018年第2期93-99,共7页Chinese Journal of Radiological Medicine and Protection

基　　金：国家重点研发计划项目（2016YFC0904700）;国家自然科学基金（81703038）;山东省重点研发计划项目（2017GSF18102）;山东省自然科学基金（ZR2017PH006）

摘　　要：目的 探讨保乳术后基于仰卧位与俯卧位实施部分乳腺外照射（EB-PBI）时靶区体积及剂量学差异。方法 2016年7月至2017年4月，30例保乳术后拟行EB-PBI的患者在自由呼吸状态下序贯完成俯卧位及仰卧位模拟定位3D-CT扫描。由同一勾画者分别在两种体位CT图像上基于术腔金属夹完成瘤床（TB）勾画和临床靶区（CTV）及计划靶区（PTV）的构建，并勾画肺脏、心脏和双侧乳腺作为危及器官（OAR）。分别制定三维适形EB-PBI治疗计划，比较两种体位靶区间及OAR剂量体积差异。结果 基于仰卧位、俯卧位勾画的TB分别为14.40和14.10 cm^3，CTV分别为57.35和62.60 cm^3，PTV分别为108.85和113.70 cm^3，俯卧位CTV及PTV均大于仰卧位（Z=-3.01、-2.87，P〈0.05），而不同体位间TB差异则无统计学意义（P〉0.05）。靶区均匀性指数（HI）分别为0.09和0.10，俯卧位大于仰卧位（Z=-3.137，P〈0.05），靶区适形指数（CI）分别为0.69和0.78，仰卧位小于俯卧位（t=9.034，P〈0.05）。两种体位EB-PBI计划中，心脏平均受照剂量（Dmean）分别为0.34和1.19 Gy，俯卧位大于仰卧位（Z=-4.12，P〈0.05）；患侧肺Dmean分别为1.72和1.59 Gy，俯卧位小于仰卧位（Z=-2.18，P〈0.05）；患侧乳腺Dmean分别为10.01和10.40 Gy，差异无统计学意义（P〉0.05）。结论 对于中国乳腺癌保乳患者而言，在自由呼吸状态下基于俯卧位实施三维适形EB-PBI是可行的。在降低患侧肺脏受照剂量以及提高靶区适形指数方面，俯卧位较仰卧位有明显优势。Objective To investigate the difference of target volumes and dosimetric parameters between supine and prone positions for external-beam partial breast irradiation （EB-PBI） after breast-conserving surgery （BCS）. Methods Thirty breast cancer patients with T1N0M0 stage who underwent three-dimensional conformal radiation therapy （3D-CRT） EB-PBI after BCS were enrolled from July 2016 to April 2017. Supine and prone scan sets were acquired during free breathing for all patients. Target volumes and organs at risk （OARs） including heart, ipsilateral lung and bilateral breast were contoured by the same radiation oncologist. The tumor bed （TB） was determined based on surgical clips. The clinical target volume （CTV） consisted of the TB plus 1.0 cm margin and the planning target volume （PTV） was CTV plus 0.5 cm. Dosimetric parameters for target volumes and OARs were compared between supine and prone positions. Results The median volumes of the TB, the CTV and the PTV in supine were 14.40 cm^3, 57.35 cm^3, 108.85 cm^3 and 14.10 cm^3,62.60 cm^3, 113.70 cm^3 for prone positions, respectively. The CTV and PTV in prone position were significantly greater than those in supine position, respectively （Z=-3.01,-2.87, P〈0.05）, but the TBs were not statistically different （P〉0.05）. The median homogeneity indexs （HI） in supine position was less than those in prone position （Z=-3.137, P〈0.05）, while the mean conformal indexs （CI） was increased with prone positioning （t=9.034, P〈0.05）. The mean dose （Dmean） to the heart in the supine position was significantly lower than that in prone （0.34 and 1.19 Gy, Z=-4.12, P〈0.05）. The Dmean to the ipsilateral lung in the prone position was significantly lower than that in supine （1.59 and 1.72 Gy, Z=-2.18, P〈0.05）. There was not significantly statistical difference for the Dmean to the ipsilateral breast between two positionings（10.01 and 10.40 Gy, P〉0.05）. Conclusions It was feasible to carry out 3D-CRT EB-PBI in pr

关 键 词：保乳术后 外照射 体位 靶区 剂量学 

分 类 号：R730.55[医药卫生—肿瘤] R737.9[医药卫生—临床医学]