Department of Radiation Oncology, Shandong Cancer Hospital, 440 Jiyan Road, Jinan, 250117, China.
J Radiat Res. 2013 Jan;54(1):182-9. doi: 10.1093/jrr/rrs068. Epub 2012 Aug 21.
We investigated the dosimetric differences among volumetric-modulated arc radiotherapy (RapidArc, RA) plans designed for various target volumes in hepatocellular carcinoma (HCC). Ten HCC patients underwent 3D-CT scanning at free breathing (FB), 3D-CT at end inspiration hold (EIH) assisted by an Active Breathing Coordinator (ABC), and 4D-CT scanning. Gross tumor volumes (GTVs) were manually contoured on CT images. The individualized internal gross target volume (IGTV(1)) was obtained from 10 GTVs from 4D-CT images. Tumor individual margins were measured from GTV(FB) to IGTV(1). The IGTV(2) was obtained from GTV(FB) by applying individual margins. Four planning target volumes (PTV(1-4)) were obtained from IGTV(1), IGTV(2), GTV(FB), and GTV(EIH), respectively. An RA plan was designed for each of the PTVs (RA(1-4)). One 358° arc was used for PTVs(1-3), while three 135° arcs were used for PTV(4). It was found that PTV(2) and PTV(3) were larger than PTV(1) and PTV(4). The mean values of PTV(3)/PTV(1) and PTV(3)/PTV(4) were 2.5 and 1.9, respectively. The individual margins in the X, Y and Z axial directions varied greatly among these patients. There were no significant differences in the conformal index or homogeneity index among the four RA plans. RA(1) and RA(4) significantly reduced the radiation dose of normal liver tissue compared with RA(2) and RA(3) (P < 0.01). There were no significant differences between the radiation doses of the stomach and duodenum. RapidArc combined with 4D-CT or ABC technology is a promising method in radiotherapy of HCC, and accurately targeted the tumor volume while sparing more normal liver tissue.
我们研究了在肝细胞癌（HCC）中，为不同靶区设计的容积旋转调强弧形放疗（RapidArc，RA）计划之间的剂量学差异。十名 HCC 患者分别在自由呼吸（FB）、在主动呼吸控制系统（ABC）辅助下进行吸气末屏气（EIH）的 3D-CT 扫描和 4D-CT 扫描。在 CT 图像上手动勾画大体肿瘤体积（GTV）。从 4D-CT 图像的 10 个 GTV 中获得个体化内部大体肿瘤靶区（IGTV(1)）。从 GTV(FB)到 IGTV(1)测量肿瘤个体边界。IGTV(2)从 GTV(FB)通过应用个体边界获得。分别从 IGTV(1)、IGTV(2)、GTV(FB)和 GTV(EIH)获得四个计划靶区（PTV(1-4)）。为每个 PTV（RA(1-4)）设计了一个 RA 计划。对于 PTVs(1-3)，使用一个 358°弧，对于 PTV(4)，使用三个 135°弧。结果发现，PTV(2)和 PTV(3)大于 PTV(1)和 PTV(4)。PTV(3)/PTV(1)和 PTV(3)/PTV(4)的平均值分别为 2.5 和 1.9。这些患者在 X、Y 和 Z 轴方向上的个体边界差异很大。四个 RA 计划的适形指数或均匀性指数之间没有显著差异。与 RA(2)和 RA(3)相比，RA(1)和 RA(4)显著降低了正常肝组织的照射剂量（P<0.01）。胃和十二指肠的照射剂量无显著差异。RapidArc 结合 4D-CT 或 ABC 技术是 HCC 放射治疗的一种很有前途的方法，既能准确靶向肿瘤体积，又能保护更多的正常肝组织。
