Jin-Zhi Wang1, Jian-Bin Li2, Wei Wang3, Huan-Peng Qi3, Zhi-Fang Ma3, Ying-Jie Zhang3, Feng-Xiang Li3, Ting-Yong Fan3, Qian Shao3, Min Xu3. 1. Department of Thoracic Radiation Oncology, Shandong Cancer Hospital, Jinan, China; Medicine and Life Sciences College of Shandong Academy of Medical Sciences, Jinan University, China. 2. Department of Thoracic Radiation Oncology, Shandong Cancer Hospital, Jinan, China. Electronic address: lijianbin@msn.com. 3. Department of Thoracic Radiation Oncology, Shandong Cancer Hospital, Jinan, China.
Abstract
BACKGROUND AND PURPOSE: 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). METHODS AND MATERIALS: 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. RESULTS: 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. CONCLUSIONS: 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.
BACKGROUND AND PURPOSE: 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). METHODS AND MATERIALS: 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. RESULTS: 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. CONCLUSIONS: 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.
Authors: Danny Lee; Peter B Greer; Carminia Lapuz; Joanna Ludbrook; Perry Hunter; Jameen Arm; Sean Pollock; Kuldeep Makhija; Ricky T O'Brien; Taeho Kim; Paul Keall Journal: Adv Radiat Oncol Date: 2017-03-10