肺内孤立性病灶不同时间段位移四维CT测量差异分析

Comparison of the solitary pulmonary lesion motion in different time periods based on four-dimensional CT images

目的：探讨基于四维CT（4DCT）测得的自由呼吸状态下肺内孤立性病灶、隆突及膈肌不同时间段位移的差异，以合理安排定位与治疗时间。方法：将2011-02—22—2012-03—27山东省肿瘤医院放疗科接受适形放疗的26例周围型肺癌或肺转移癌患者随机分成上午组和下午组，14例在9：00～11：00、12例在14：00～16：00行4DCT扫描，分别在呼气末和吸气末时相勾画GTV，比较上、下午组患者GTVq-心在左右、头足和前后方向的位移和GTV中心在三维空间的运动矢量及隆突和左、右侧膈肌在头足方向的运动幅度差异。结果：上午组患者GTV中心在左右、头足、前后方向的位移分别为（1．70±2．49）、（6．86±7．10）和（1．92±1．91）mm，下午组分别为（1．24±1．01）、（5．33±4．21）和（1．934-1．26）mm，三维方向上两组间差异无统计学意义，P〉0．05；但左右和头足方向，上午组位移略大于下午组。上、下午组患者GTV中心三维运动矢量分别为（7．74±7．32）和（6．13±4．01）mm，差异无统计学意义，P〉0．05。上午组隆突及右、左侧膈肌在头足方向的位移为（5．70±2．31）、（15．64±7．54）和（14．11±4．81）mm，下午组为（5．86±1．74）、（14．18±5．87）和（12．08±3．85）mm，差异均无统计学意义，P〉0．05。结论：自由呼吸状态下肺内孤立性病灶三维方向的位移及隆突和膈肌头足方向的运动幅度在上、下午间差异均不明显，提示放疗定位与放射治疗的时间可以不同步。

OBJECTIVE： To compare the motion differences in different time periods based on four-dimensional CT （4D CT） for solitary pulmonary lesion （SPL）,and the motion of carina, diaphragm in SI direction during free breathing, and to arrange the time of simulation and radiotherapy rationally. METHODS： Twenty-six patients with peripheral lung cancers or pulmonary metastasis tumors received radiotherapy were divided into two groups randomly： 14 patients under went 4DCT scans in forenoon （9：00--11：00）（group A）,and 12 in afternoon （14：00-16：00） （group B） from 2011 to 2012. GTV was delineated on the end inspiration and end expiration phases of 4D CT images. The differences in the GTV three dimensional motion and the motion vector were compared between the two groups. The car±ha and diaphragm move- ment in superoinferior （SI） direction were measured and the differences in the motion amplitude were compared between group A and group B. RESULTS： The GTV displacement were （1.70±2.49） ,（6.86±7.10）,（1.92±1.91） ram,respec- tively in lateral （LR） ,SI and anteroposterior （AP） directions for group A,and （1.24±1.01） ram,（5.33±4.21） mm,and （1.93± 1.26） mm for group B,and there were no statistically significant difference between the two groups （P）0.05）, but in LR and AP directions,GTV motion of group A was slightly bigger than that of group B. The GTV centroid motion for group A and group B in motion vector were （7. 74±7.32） and （6. 13±4.01） ram,and no significant difference was found （P〈0.05）. The car±ha,right diaphragm and left diaphragm motion in SI direction were （5.70±_2.31）, （15.64± 7.54） ,（14.11±4.81） mm for group A,and （5.86±1.74） ram, （14.18±5.87） mm and （12.08±3.85） ram,respectively for group B,and there was also no statistically significant difference between the two groups （P〈0.05）. CONCLUSIONS： During free breathing,there are no statistically significant difference in three dimensional motions for SPL and the motions of carina, diaphragm in SI direction between forenoon and in afternoon. It suggests that CT simulation and the radiotherapy could be received for patients at different time periods.