基于4DCT探讨金属夹、血清肿及两者结合勾画靶区对EB—PBI剂量学参数影响  

Dosimetric effects of target volume delineation with metal clip and seroma, alone or in combination, on external-beam partial breast irradiation：a study based on four-dimensional computed tomography

作　　者：国兵[1] 李建彬[1] 王玮[1] 李奉祥[1] 郭延娈 李彦康 刘同海[1] 

机构地区：[1]济南大学山东医学科学院医学与生命科学学院山东省肿瘤医院放疗科,250117

出　　处：《中华放射肿瘤学杂志》2016年第9期975-979,共5页Chinese Journal of Radiation Oncology

摘　　要：目的基于4DCT扫描探讨金属夹、血清肿及两者结合勾画靶区对部分乳腺外照射（EB—PBI）的剂量学参数影响。方法选取2009-2013年间接受保乳手术并符合EB—PBI条件的20例患者人组。在4DCT10个时相上，分别基于金属夹、血清肿及两者结合勾画GTVc、GTVs、GTVc＋s，并将10个时相图像上GTV分别融合得到IGTVc、IGTVs、IGTVc＋s，边界外扩15mm作为PTVc、PTVs、PTVc＋s。由同一物理师在吸气末时相图像上分别基于PTVc、PTVs、PTV。制定3DCRT计划，比较3组间靶体积、HI、cI及OAR剂量体积差异。结果3个组间IGTV、PTV及PTV与患乳体积比差异均有统计学意义（P均〈0．05），血清肿组〈金属夹组〈金属夹结合血清肿组．血清肿组患侧正常乳腺、患侧肺受量小于金属夹组及金属夹结合血清肿组（P均〈0．05），3个组间HI、CI差异均无统计学意义（P均〉0．05）。结论在4DCT图像上基于不同参照物构建靶区导致的体积差异对靶区剂量分布无明显影响，但对患侧乳腺及患侧肺受量却有明显影响。Objective To evaluate the dosimetric effects of target volume delineation with metal clip and seroma, alone or in combination, on external-beam partial breast irradiation （EB-PBI） based on fourdimensional computed tomography （4DCT）. Methods Twenty female patients undergoing EB-PBI from 2009 to 2013 were enrolled as subjects. The gross tumor volumes （ GTVs ）, GTVc, GTVs, and GTVc^s, were delineated on 4DCT images at 10 phases using metal clip, seroma, and both of them, respectively. The GTVs on 4DCT images at 10 phases were fused to generate the internal gross tumor volumes （ IGTVs ）, IGTVc, IGTVs, and IGTVc^s. The planning target volumes （PTVs）, PTVc, PTVs, and PTVc^s, were obtained via expansion of margin by 15 mm. The three-dimensional conformal radiotherapy plans were made by one physician based on PTVc, PTVs, and PTVc＋s on end-inhalation images. The target volume, homogeneity index （HI）, conformity index （CI）, and doses to organs at risk were compared between the three groups. Results The c＋s group had the largest IGTV, PTV, and the ratio of PTV to diseased breast volume, which was followed by the C group and the S group （all P〈0. 05）. The S group had significantly lower doses to the ipsilateral normal breast and lung than the C group and the c^s group （ all P〈0. 05）. There were no significant differences in HI or CI between the three groups （ all P〉 0. 05 ）. Conclusions The volume variation caused by target volume delineation on 4DCT images based on different references has little impact on dose distribution in target volume. However, it has substantial impact on radiation doses to the ipsilateral normal breast and lung.

关 键 词：部分乳腺外照射 体层摄影术 x线计算机 四维 金属夹 血清肿 靶区确定 

分 类 号：R730.55[医药卫生—肿瘤]