不同呼吸状态3DCT与4DCT终末时相间相关解剖结构位置及体积比对研究

目的：比较自主呼吸控制（activebreathingcontrol，ABC）辅助三维CT（threedimensionalCT，3DCT）平静吸气末和呼气末与四维CT（fourdimensionalCT，4DCT）终末时相间膈顶、肺脏和心脏位置和（或）体积差异。方法：选取2011-08—03—2011—12—12在山东省肿瘤医院行放疗的15例周围型肺癌患者，依次完成胸部4DCT扫描及ABC辅助平静吸气末（CTEIH）和呼气末（CTEEH）3DCT扫描。将每个呼吸周期的4DCT图像平均分为10个呼吸时相，0时相定义为吸气末时相（CT0），50％时相定义为呼气末时相（CT50），分别在CT0、CT50、CTETH和CTEEH上勾画双肺、心脏及双膈肌顶。结果：CTⅡH和CTEEH间（Z=-1．21，P=0．228）与CT0和CT50间（Z=-1．62，P=0．106）左右膈肌顶头脚方向位移的平均差值均≤1．5mm，且差异均无统计学意义；CTEIH和CT0间、CTEEH和CT50间左右肺及心脏中心点位置的差异，在头脚方向上差异均有统计学意义（Z=-3．27～-1．93，P=0．001～0．047），在径向方向上差异均无统计学意义，Z=-1．58～-0．26，P=0．128-0．798；CTEIH和CTEEH左右肺体积均大于CT0和CT50左右肺体积，差异均有统计学意义（t=-5．07～-2．25，P=0．000～0．041），而心脏体积CT0和CT50（t=2．10，P=0．054）均大于CTEIH和CTEEH（t=1．85，P=0．085），但差异均无统计学意义。结论：从保护肺和心脏的角度看，在其他条件相同时，基于ABC辅助平静吸气末门控放疗优于基于4DCT吸气末门控放疗。

Position and volume of related anatomical structures between quiet end-inspiration and end-expiration three dimensional CT assisted with active breathing control and corresponding phases in four dimensional CT

OBJECTIVE：To compare the position and/or volume of diaphragm dome,lung and heart between quiet end-inspiration and end-expiration three dimensional CT （3DCT） assisted with active breathing control （ABC） and the corresponding phases in four dimensional CT （4DCT）. METHODS： Fifteen patients with peripheral lung cancer received radiotherapy in Shandong Cancer Hospital from Aug. 3,2011 to Dec. 12,2011 underwent 4DCT simulation scan during free breathing and 3D-CT simulation scans in end-inspiratory hold （CTEIH） and end-expiratory hold （CTEEH） in succes- sion. The 4DCT images from each respiratory cycle were sorted into 10 phases：the 0 phase was defined as end-inspiratory phase （CT0）,while the 50 phase was defined as end-expiratory phase （CT50）. The left and right lungs, heart,and both diaphragm domes were delineated separately on CT0 ,CT50 ,CTEIH and CTEEH images. RESULTS： In the cranio-caudal direc- tion, between CTEIH and CTEEH ,CT0 and CT50, the mean displacement differences of both diaphragm domes were not larger than 1.5ram and were not statistically significant （Z ranged from --1.62 to --1.21,P ranged from 0. 106 to 0. 228）. Be- tween CTEIH and CT0 ,CTEEH and CT50 ,the centroid position differences of two lungs and heart were found all statistically significant （Z ranged from --3.27 to --1.93,P ranged from 0. 001 to 0. 047） in the cranio-caudal direction, and not statis- tically significant （Z ranged from --0.26 to --1.58,P ranged from 0. 128 to 0. 798） in the radial directions. The volumes of two lungs were both larger in （TEIH and CTEEH than in CT0 and CT50,and the differences between them were fouud both statistically significant （t = -5.07, --2.25;P 0. 000,0.041 ）, while the volume of heart was larger in CT. and CT50, than in CTEIH and CTEEH,but the differences between them were found both no statistical significace （t=2. 10,1.85;P= 0.05,1,0. 085）. CONCLUSION： From the point of view of the lung and beart protection, when other conditions are same, gated radiotherapy in quiet end inspiration is better basing on ABC than basing on 4DCT.