| 李奉祥,李建彬,马志芳,张英杰,邢军,戚焕鹏,尚东平,余宁莎.基于3D-CT、4D-CT和锥形束CT定义的非小细胞肺癌内靶区比较[J].中华放射医学与防护杂志,2014,34(2):110-115 |
| 基于3D-CT、4D-CT和锥形束CT定义的非小细胞肺癌内靶区比较 |
| Comparison of internal target volumes defined on three-dimensional CT, four-dimensional CT and cone-beam CT images of non-small-cell lung cancer |
| 投稿时间：2013-03-26 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.02.009 |
| 中文关键词: 非小细胞肺癌 三维CT 四维CT 锥形束CT 内靶区 |
| 英文关键词:Non-small-cell lung cancer Three-dimensional CT Four-dimensional CT Cone-beam CT Internal target volume |
| 基金项目:国家自然科学基金（81201735）；山东省科技发展计划项目（2012GSF11839）；山东省自然科学基金（ZR2011HM004） |
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| 中文摘要: |
| 目的 比较基于三维CT（3D-CT）、四维CT（4D-CT）和锥形束CT（CBCT）图像定义的非小细胞肺癌（NSCLC）内靶区（ITV）位置和体积差异。方法 31例周围型NSCLC患者，完成胸部3D-CT和4D-CT定位扫描，放疗首次拍摄CBCT。在3D-CT、4D-CT最大密度投影（MIP）、CBCT图像上勾画大体肿瘤靶区（GTV），定义GTV到临床靶区（CTV）的外扩边界为7 mm，获得CTV3D、ITVMIP 和ITVCBCT。基于CTV3D在左右、前后方向外扩5 mm，头脚方向外扩5 mm得到ITV5 mm、外扩10 mm得到ITV10 mm。比较靶区间位置、体积、相似度和相互包含关系差异。结果 肺上叶组中，ITV10 mm、ITV5 mm、ITVMIP 和ITVCBCT的中位比值分别为2.33、1.88和1.03，中下叶组的分别为2.13、1.76和1.10，两组间差异均无统计学意义。全组ITVMIP 与ITVCBCT间相似度的中位数为0.83，大于ITV10 mm 与ITVCBCT间（0.60）和ITV5mm 与ITVCBCT间的相似度（0.66）（Z=-4.86、-4.86，P<0.05）。全组ITVCBCT未被ITV10 mm、ITV5 mm、ITVMIP 包含比例的中位数分别为0.10%、1.63%和15.21%，而ITV10 mm、ITV5 mm、ITVMIP未被ITVCBCT包含的比例分别为57.08%、48.89%和20.04%。肺上叶组和中下叶组ITVCBCT未被ITV5 mm包含比例的中位数为1.24%和5.8%，两组差异无统计学意义。结论 基于4D-CT定义的个体化ITV不能有效地包含基于CBCT定义的在线ITV，利用源于4D-CT的ITV制定放疗计划，可能导致脱靶。基于常规3D-CT均匀外扩定义的ITV能够较好包含源于CBCT的ITV，但体积远远大于后者。 |
| 英文摘要: |
| Objective To compare positional and volumetric differences between internal target volumes defined on three-dimensional CT (3D-CT), four-dimensional CT (4D-CT) and cone-beam CT (CBCT) images of non-small-cell lung cancer. Methods Thirty-one patients with NSCLC sequentially underwent 3D-CT and 4D-CT simulation scans of the thorax during free breathing. A 3D conformal treatment plan was created based on 3D-CT. The CBCT images were obtained in the first fraction and registered to the planning CT using the bony anatomy registration. All target volumes were contoured with the same protocol by a radiation oncologist. GTVs were contoured based on 3D-CT, maximum intensity projection (MIP) of 4D-CT and CBCT. CTV3D, ITVMIP and ITVCBCT were defined with a margin of 7 mm accounting for microscopic disease. ITV10 mm and ITV5 mm were defined based on CTV3D. ITV10 mm with a margin of 5 mm in LR, AP directions and 10 mm in CC direction, while ITV5 mm with an isotropic internal margin (IM) of 5 mm. The differences in the position, size, Dice's similarity coefficient (DSC) and inclusion relation of different volumes were compared. Results The median size ratio of ITV10 mm, ITV5 mm, ITVMIP to ITVCBCT were 2.33, 1.88, 1.03 respectively for tumors in the upper lobe and 2.13, 1.76, 1.10 respectively for tumors in the middle-lower lobe. The median DSC of ITVMIP and ITVCBCT (0.83) was greater than that of ITV10 mm and ITVCBCT (0.6) and ITV5 mm and ITVCBCT (0.66) for all patients(Z=-4.86, -4.86,P<0.05). The median percentages of ITVCBCT not included in ITV10 mm, ITV5 mm, ITVMIP were 0.10%, 1.63% and 15.21% respectively, while the median percentage of ITV10 mm, ITV5mm, ITVMIP not included in ITVCBCT were 57.08%, 48.89% and 20.04%, respectively. The median percentage of ITVCBCT not included in ITV5 mm was 1.24% for tumors in the upper lobe and 5.8% for tumors in the middle-lower lobe. Conclusions The individual ITV based on 4D-CT can't encompass the ITV based on CBCT effectively. The use of the ITV derived from 4DCT in radiotherapy may result in a target miss. The ITVs based on 3D-CT with istropic margins can encompass the ITV from CBCT, but the size might be far greater than the latter. |
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