Wang Jin-Zhi, Li Jian-Bin, Wang Wei, Qi Huan-Peng, Ma Zhi-Fang, Zhang Ying-Jie, Li Feng-Xiang, Fan Ting-Yong, Shao Qian, Xu Min
Department of Thoracic Radiation Oncology, Shandong Cancer Hospital, Jinan, China; Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, China.
Department of Thoracic Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
Radiother Oncol. 2015 Feb;114(2):201-5. doi: 10.1016/j.radonc.2014.12.010. Epub 2015 Jan 13.
Variations of target volume and position were important factors in correction of radiotherapy planning. The purpose was to investigate the changes in volume and motion of oesophageal cancer during radiotherapy using four-dimensional computed tomography (4D-CT).
In total, 109 enhanced 4D-CT data sets were acquired for 38 patients throughout treatment. Gross tumour volumes (GTVs) were outlined on each data set. Variations in volume, motion, and position were calculated for GTV and internal GTV (IGTV) during treatment.
GTV (25%, P<0.01) and IGTV (27%, P<0.01) had decreased significantly when measured at the twentieth fraction. Larger intrafractional GTV centre shifts (P<0.01) were observed in the superior-inferior direction (median value of 3.1mm) compared with the right-left and anterior-posterior directions (1.6mm and 1.4mm, respectively). The interfractional shift of the IGTV centre was not significant during radiotherapy. The overlap ratios of the targets decreased for both GTV and IGTV during treatment.
Variations in GTV and IGTV centre shifts were not significant throughout treatment. However, tumour volume decreased significantly by the twentieth fraction. Finally, changes in oesophageal tumour volume and motion may decrease the overlap ratio for GTV and IGTV during radiotherapy.
靶区体积和位置的变化是放疗计划校正的重要因素。本研究旨在利用四维计算机断层扫描（4D-CT）探讨食管癌放疗期间体积和运动的变化。
共为38例患者在整个治疗过程中采集了109组增强4D-CT数据集。在每组数据集上勾勒出大体肿瘤体积（GTV）。计算治疗期间GTV和内部大体肿瘤体积（IGTV）的体积、运动和位置变化。
在第20次分割时测量，GTV（25%，P<0.01）和IGTV（27%，P<0.01）显著减小。与左右方向（分别为1.6mm）和前后方向（1.4mm）相比，在上下方向观察到更大的分次内GTV中心位移（P<0.01）（中位值为3.1mm）。放疗期间IGTV中心的分次间位移不显著。治疗期间，GTV和IGTV的靶区重叠率均降低。
整个治疗过程中GTV和IGTV中心位移的变化不显著。然而，到第20次分割时肿瘤体积显著减小。最后，食管癌肿瘤体积和运动的变化可能会降低放疗期间GTV和IGTV的重叠率。
