Department of Radiation Oncology, Shandong Cancer Hospital and Institute, Jinan 250117, China.
J Radiat Res. 2013 Sep;54(5):950-6. doi: 10.1093/jrr/rrt017. Epub 2013 Apr 5.
The aim of this study was to explore the characteristic of 3DCT scanning phases and estimate the comparative amount of respiration motion information included in 3DCT and 4DCT by comparing the volumetric and positional difference between the volumes from 3DCT and 4DCT for the radiotherapy of non-small-cell lung cancer (NSCLC). A total of 28 patients with NSCLC sequentially underwent 3DCT and 4DCT simulation scans of the thorax during free breathing. The 4DCT images with respiratory signal data were reconstructed and sorted into 10 phases throughout a respiratory cycle. GTV-3D from 3DCT, GTV-0%, GTV-20%, GTV-50% and GTV-70% from end-inspiration, mid-expiration, end-expiration and mid-inspiration of 4DCT, and the internal GTV (IGTV-10) from the fused phase of 4DCT were delineated based on the 50% phase image, respectively. The differences in the position, size, matching index (MI) and degree of inclusion (DI) for different volumes were evaluated. The variation in the centroid shifts of GTV-0% and GTV-3D, GTV-20% and GTV-3D, GTV-50% and GTV-3D, and GTV-90% and GTV-3D in the 3D direction was not significant (P = 0.990). The size ratios of GTV-0%, GTV-20%, GTV-50%, GTV-70% and IGTV-10 to GTV-3D were 0.94 ± 0.18, 0.95 ± 0.18, 0.98 ± 0.15, 1.00 ± 0.18 and 1.60 ± 0.55, respectively. DIs of GTV-3D in IGTV-10, and IGTV-10 in GTV-3D were 0.88 ± 0.14 and 0.59 ± 0.16 (P < 0.001). The 3DCT scanning phases are irregular. The CTV-to-ITV expansion should be isotropic when defining the ITV on the 3DCT. The internal GTV derived from 4DCT cannot completely include the GTV from 3DCT. An additional margin may be required when defining the ITV-based 4DCT.
本研究旨在探索 3DCT 扫描相位的特征，并通过比较非小细胞肺癌（NSCLC）放疗中 3DCT 和 4DCT 容积之间的体积和位置差异，估计 4DCT 中包含的呼吸运动信息的相对量。对 28 例 NSCLC 患者在自由呼吸过程中依次进行胸部 3DCT 和 4DCT 模拟扫描。对带有呼吸信号数据的 4DCT 图像进行重建，并在整个呼吸周期内按 10 个相位进行排序。基于 50%相位图像，分别从 3DCT 勾画 GTV-3D、4DCT 吸气末、呼气中期、呼气末和吸气中期勾画的 GTV-0%、GTV-20%、GTV-50%和 GTV-70%，以及 4DCT 融合相位勾画的内部 GTV（IGTV-10）。评估不同容积的位置、大小、匹配指数（MI）和包含度（DI）的差异。3D 方向上 GTV-0%和 GTV-3D、GTV-20%和 GTV-3D、GTV-50%和 GTV-3D、GTV-90%和 GTV-3D 的质心偏移变化无显著差异（P = 0.990）。GTV-0%、GTV-20%、GTV-50%、GTV-70%和 IGTV-10 与 GTV-3D 的大小比分别为 0.94 ± 0.18、0.95 ± 0.18、0.98 ± 0.15、1.00 ± 0.18 和 1.60 ± 0.55。IGTV-10 中的 GTV-3D 的 DI 和 GTV-3D 中的 IGTV-10 的 DI 分别为 0.88 ± 0.14 和 0.59 ± 0.16（P < 0.001）。3DCT 扫描相位不规则。在 3DCT 上定义 ITV 时，CTV-to-ITV 扩展应该是各向同性的。4DCT 得出的内部 GTV 不能完全包括 3DCT 得出的 GTV。在定义基于 4DCT 的 ITV 时，可能需要额外的边界。
