中文摘要：

目的 应用4D-CT和形变配准技术,研究呼吸运动对原发性肝癌（HCC）肿瘤靶区及正常肝脏放疗剂量累加的影响.方法 选择19例已行肝动脉化疗栓塞术并准备接受放疗的HCC患者,依次接受自由呼吸下3D-及4D-CT模拟定位,将4D-CT图像依呼吸周期分为10个时相.在3D-CT图像上进行治疗计划设计,获得3D剂量（Dose-3D）,将其在4D-CT的10个序列图像中重新计算得到10个时相的相应剂量,其中吸气末（EI）及呼气末（EE）图像上的剂量分别命名为Dose-El及Dose-EE.将4D-CT的10个时相的剂量以呼气末时相为参考,经形变累加得到4D剂量（Dose-4D）.比较靶区及正常肝脏在Dose-3D、Dose-EI、Dose-EE及Dose4D间的剂量学差异.结果 Dose3D中计划靶区D99和D95均高于Dose-4D、DoseE1及Dose-EE（x2=32.75、26.31,P＜0.05）,但Dose-3D的适形指数（CI）和均匀指数（HI）较另外3种剂量分布为优,其中CI由0.78分别降至0.63、0.60、0.57,HI由0.08增至0.15、0.16、0.19（x2=37.80、31.86,P＜0.05）;而计划靶区各剂量-体积指标在Dose-4D与Dose El、Dose-EE间,以及DoseEl与Dose EE间的差异并无统计学意义（P＞0.05）.正常肝脏平均剂量（Dmean）、V5、V10、V20、V30和V40在4种剂量分布间的差异均无统计学意义（P＞0.05）.结论 4D-CT结合形变配准技术可较准确反映原发性肝癌患者放疗时靶区及正常肝脏的受量,利于对放射性肝损伤相关剂量-体积指标准确预测,可为靶区剂量的安全提升提供基础.

英文摘要：

Objective To explore the effect of respiration on dose accumulation for target volume and normal liver in radiotherapy for hepatocellular carcinoma （HCC） while applying 4D-CT and deformable registration.Methods Nineteen HCC patients who had received transcatheter arterial chemoembolization were enrolled in this study.All patients underwent 3D-and 4D-CT simulation in free breathing.The 3D dose （Dose-3D） was calculated from the treatment planning designed on the 3D-CT image.The Dose-3D then was recalculated on ten phases of 4D-CT images respectively,and the end-inspiration and end-expiration doses were defined as Dose El and Dose-EE.The 4D dose （Dose-4D） was obtained by deforming and accumulating ten-phase doses of 4D-CT images on the end-expiration phase image.The dosimetric differences of planning target volume and normal liver were compared among Dose-3D,Dose-4D,Dose-EI and Dose-EE.Results The D99 and D95of planning target volume （PTV） in Dose-3D were higher than those of Dose-4D,Dose-Fl and Dose EE （x2 =32.75,26.31,P 〈 0.05）.The conformal index （CI） and homogeneity index （HI） in Dose-3D were better than those of Dose-4D,Dose-E1 and Dose-EE,in which CI decreased from 0.78 to0.63,0.60 and 0.57,while HI increased from 0.08 to 0.15,0.16 and 0.19 （x2 =37.80,31.86,P 〈0.05）.No statistically significant differences were found in dosimetric indices of PTV between Dose-4D and Dose EI,Dose-EE,and between Dose-El and Dose-EE （P 〉 0.05）.The mean dose （D）,V5,V10,V20,V30 and V40 of normal liver were similar among four dose distributions （P 〉 0.05）.Conclusions More objective and precise dose distribution for target volume and normal liver could be obtained by applying both 4D-CT and deformable registration,which is beneficial to accurately predicting the dosevolume indices of radiation-induced liver injury and offering more reliable evidence of escalation for target dose.