四维CT 呼吸门控技术联合图像引导放射治疗在肺癌中的应用

摘要

目的：探讨四维CT （4D-CT ）呼吸门控技术联合图像引导放射治疗（IGRT ）在肺癌中的应用研究。方法38例患者进行4D-C T定位扫描，每位患者得到10组不同呼吸时相：0～90％，分别制定3D计划和4D计划，通过体积直方图评价两计划；执行4D计划进行IGRT治疗的患者，治疗结束后随访2～3个月，分析疗效及并发症。结果肺癌呼吸运动位移在三维方向不同，头脚方向最大，约（9．1±2．2）mm ，距离精度2．6 mm。两种计划中4D计划的临床靶区（CTV）＞3D计划，而PTV明显小于3D计划，肺V20、平均肺剂量（MLD）均低于3D计划，差异有统计学意义（P＜0．05）。P-4D总有效率为77．78％（28/38），急性放射性肺损伤1、2、3级发生率80．56％、16．67％、2．78％，急性放射性食管炎1、2级发生率为80．56％，8．33％。结论基于4D-C T的呼吸门控技术在肺癌的IGRT临床应用中是可行的，减少计划靶区的体积，有利于放射治疗精度的提高。呼吸动度个体差异明显，内靶区外扩范围应个体化。%Objective To explore the preliminary study of the four-dimensional CT-based respiratory gating applications in the IGRT treatment of lung cancer .Methods 38 patients′ were scanned with 4D-CT ,and could got 10 images:0-90% each one ,and then two kinds of radiation treatment plans :Plan-3D and Plan-4D were used ,respectively .Treatment of the patients in the IGRT mode with Plan-4D and following up were done in two months after treatment to evaluate the efficacy and complication probability . Meanwhile evaluation of the two plans by the volume histogram was done .Results The displacement of lung tumor respiratory mo-tion was different in three dimensions ,especially in the Vertical direction ,about(9 .1 ± 2 .2)mm .Accuracy of the distance was 2 .6 mm .The Plan-4D′s CTV was bigger than Plan-3D ,but its PTV was less than the Plan-3D significantly ,at the same time its lung V20 ,MLD were both less than the Plan-3D ,and the difference was statistically significant(P< 0 .05) .The total efficiency(CR+PR)was 77 .78% (28 case);the incidence of 1 ,2 ,3 acute radiation-induced lung injury were 86 .11% ,11 .11% ,2 .78% ,respectively ;the incidence of 1 ,2 acute radiation esophagitis injury were 80 .56% ,8 .33% .Conclusion The respiratory gating techniques based on 4D CT applied in image guided radiotherapy of lung cancer in clinical is feasible ,and it can reduce the volume of the planning tar-get volume ,and help to improve the accuracy of radiotherapy .The degree of respiratory motion is significantly different in individu-als ,and expanding outside the target ranges should be individualized .