摘要目的 通过比较自由呼吸固定(A)与腹部球囊加压配合4DCT固定(B)技术在NSCLC中患者的靶区大小,各方向移动幅度及移动向量、患侧肺受量及全肺体积、摆位误差的差异,说明腹部球囊加压配合4DCT固定技术可以有效应用于NSCLC.方法 回顾分析本院行A、B方法的NSCLC患者各40例.将两种方法分别得出10个呼吸时相图像生成MIP序列上勾画GTVfree与GTVpress,外放得到PTVfree与PTVpress.配对t检验PTVfree与PTVpress大小及随呼吸运动靶区在三维方向最大移动幅度、三维方向位移向量绝对值|V|及体积差异.通过TPS设计比较两种方法患侧肺V5、V10、V20、V30及全肺体积;所有患者摆位完成后进行CBCT扫描得到图像在XVI系统中与MIP进行骨性加灰度匹配得出摆位误差.结果 PTVfree与PTVpress分别为(283.2±12.74)、(201.8± 12.99) cm3(P=0.002).两种固定方法在左右、上下、前后方向最大移动幅度及三维空间位移向量|V|分别为(0.22±0.02)、(1.85±0.08)、(0.43±0.26) cm和(1.91±0.27) cm;(0.05±0.01)、(0.41±0.03)、(0.16±0.16) cm和(0.44±0.16) cm (P=0.120、0.001、0.070);患侧肺V5、V10、V20、V30及全肺体积分别为(61.26±4.27)％、(44.52±1.70)％、(28.22±3.13)％、(18.26±5.17)％及(3 556±223.12) cm3;(52.74±4.78)％、(38.76±4.92)％、(23.7l±4.03)％、(15.54±3.43)％及(3 376±311.65) cm3(P=0.001、0.003、0.004、0.021、0.004).通过XVI得出的两种固定方法的摆位误差无统计学意义(P均＞0.05).结论 NSCLC患者采用腹部球囊加压在没有增加摆位误差的同时可以有效控制患者肺的移动幅度、减小计划靶区的外放及减少肺的照射剂量.

abstractsObjective To compare the size of target volume,amplitudes of movements in different directions,movement vector,dose to the diseased lung,whole lung volume,and setup error between free breathing fixation (method A) and four-dimensional computed tomography (4DCT)-guided abdominal balloon compression fixation (method B),and to demonstrate that the 4DCT-guided abdominal balloon compression fixation is effective in the treatment of non-small cell lung cancer (NSCLC).Methods A retrospective analysis was performed among 80 patients with NSCLC in our hospital.In those patients,40 received method A and 40 method B.The GTVfree and GTVpress were delineated on the maximum intensity projection (MIP) images of 10 respiratory phases using method A and method B,respectively.The PTVfree and PTVPress were obtained by expansion of the GTVfree and GTVpress,respectively.The paired t test was used to analyze the differences in the PTV,maximum amplitudes of movements in three dimensions,absolute value of the movement vector (|V|),and volume between method A and method B.The treatment planning system was used to compare the V5,V10,V20,and V30 of the diseased lung and the whole lung volume between method A and method B.All patients underwent cone-beam CT (CBCT) scans after positioning.Setup error was obtained by matching the CBCT images with the MIP images in the XVI system based on bone and grayscale values.Results The PTVfree and PTVpress were (283.2± 12.74) and (201.8± 12.99)cm3,respectively (P=0.002).The maximum amplitudes of movements in the right-left,superior-inferior,and anterior-posterior directions as well as thel V | value were (0.22±0.02),(1.85±0.08),(0.43±0.26),and (1.91±0.27) em,respectively,for method A,and (0.05±0.01),(0.41±0.03),(0.16±0.16),and (0.44±0.16) cm,respectively,for method B (P=0.120,0.001,0.070).The V5,V10,V20,and V30 for the diseased lung and total lung volume were (61.26± 4.27) ％,(44.52± 1.70) ％,(28.22± 3.13) ％,(18.26±5.17)％,and (3556±223.12) cm3,respectively,for method A,and (52.74±4.78)％,(38.76±4.92) ％,(23.71 ±4.03) ％,(15.54±3.43) ％,and (3376±311.65) cm3,respectively,for method B (P =0.001,0.003,0.004,0.021,0.004).There was no significant difference in setup error obtained by the XVI system between the two fixation methods (P＞0.05).Conclusions Without increasing setup error,abdominal balloon compression can effectively control the lung movement amplitude,reduce the planning target volume,and reduce the radiation dose to the lung in patients with NSCLC.