3D/4D CT和3D/4D CBCT在不同运动模式下的模体靶区体积差异  

Comparison of Tumor Volume Between 3D/4D CT and 3D/4D CBCT Under Respiratory Motion

作　　者：王涛[1] 刘晓男 毛荣虎 程秀艳 郭跃信[1] WANG Tao;LIU Xiaonan;MAO Ronghu;CHENG Xiuyan;GUO Yuexin(Department of Radiation Treatment Medicine,the First Affiliated Hospital of ZhengZhou University,Zhengzhou 450000,China;Department of Radiation,Affiliated Cancer Hospital of ZhengZhou University/Henan Cancer Hospital,Zhengzhou 450008,China)

机构地区：[1]郑州大学第一附属医院放射治疗医学部,河南郑州450000 [2]郑州大学附属肿瘤医院/河南省肿瘤医院放疗科,河南郑州450008

出　　处：《河南医学研究》2024年第22期4047-4051,共5页Henan Medical Research

摘　　要：目的评估3D/4D CT和3D/4D CBCT在不同运动模式下模体的内靶区成像的体积差异,以期探讨不同运动模式下各种成像方式在肺体部立体定向放射治疗(SBRT)的图像引导放疗应用的准确性。方法本研究采用CIRS胸部动态模体模拟呼吸运动,使用直径3 cm小球插件,设定振幅分别为5 mm、10 mm的sin(x)和cos 4(x)波形的运动曲线,周期4 s,分别采集3D/4D CT(飞利浦CT)和3D/4D CBCT(医科达加速器)图像,测量不同运动模式下,3D CT、4D CT的平均密度投影CT(4D CT-AIP)、4D CT的最大密度投影CT(4D CT-MIP)、4D CT的全部时相(4D CT-ALL%)和3D CBCT、4D CBCT的平均密度投影CT(4D CBCT-AIP)、4D CBCT的最大密度投影CT(4D CBCT-MIP)各自图像插件小球内靶区体积并进行分析。结果3D CT的靶区体积最小;4D CT-ALL、4D CT-MIP和4D CBCT-MIP三者靶区体积大小接近;3D CT的ITV与ITV-ALL的相似度最低,3D CBCT的ITV与ITV-ALL的相似度接近,4D CT和4D CBCT的ITV(MIP-ALL)的相似度最高,4D CT和4D CBCT图像ITV(AIP-ALL)的相似度均低于ITV(MIP-ALL)。结论对于运动靶区,4D CT联合4D CBCT更能准确提供各时相的肿瘤靶区勾画和运动轨迹验证,是一种可靠的肺SBRT定位及引导模式。Objective To evaluate the differences of internal target volume imaging between 3D/4D CT and 3D/4D CBCT in different motion modes,and to investigate the accuracy of various imaging methods in image-guided radiotherapy of lung stereotactic body radiation therapy under different motion modes.Methods A dynamic thorax phantom inserted with a mimic tumor with a diameter of 3 cm was programmed to simulate one-dimensional respiratory motion(period:4 s)in the superior-inferior direction.Four tumor motion patterns were simulated with functions of sin(x)and cos 4(x),each with an amplitude of 10 mm and 5 mm,to achieve phantom images of 3D/4D CT and 3D/4D CBCT.All the 3D/4D CT images were obtained using Philips CT,all the 3D/4D CBCT images were collected using Elekta XVI Symmetry system.The volume of tumor inserted in the phantom were measured separately in the images of 3D CT,4D CT-average intensity projection(4D CT-AIP),4D CT-maximum intensity projection(4D CT-MIP),4D CT-ALL phases,and 3D CBCT,4D CBCT-AIP,4D CBCT-MIP,4D CBCT-ALL phases.Results The target volume of 3D CT was the smallest.In comparison,the volumes of 4D CT-ALL,4D CT-MIP,and 4D CBCT-MIP were similar.The Dice’s similarity coefficient(DSC)between the ITV from 3D CT and ITV-ALL was the lowest,while that between the ITV from 3D CBCT and ITV-ALL was close.The DSC between the ITV(MIP-ALL)of 4D CT and 4D CBCT was the highest,and the DSC between the ITV(AIP-ALL)of 4D CT and 4D CBCT images was lower than that of ITV(MIP-ALL).Conclusion Quantitative information can be extracted from on-board treatment verification imaging(4D CBCT),and the combination of 4D CT and 4D CBCT could be an effective and alternative method for lung SBRT.

关 键 词：CT 锥形束CT 体部立体定向放射治疗 

分 类 号：R445[医药卫生—影像医学与核医学]