对于术前胃癌放射治疗的图像引导策略的选择和开发，需要定量了解胃部解剖变化的各种来源。本研究旨在使用内部标记和四维成像来调查间隙性和内部性胃部运动和变形的幅度。在接受术前胃癌放射治疗的十四名患者中，胃部分布有2-6个内部标记（共54个标记），并进行了额外成像（即一项计划的四维CT（pCT），20-25项治疗前四维CBCT，4-5项治疗后四维CBCT）。通过骨骼解剖匹配，获取了所有呼气末和吸气末扫描的标记坐标。对五个解剖区域（即贲门、小曲张、近远大曲张和幽门）评估了间隙性标记位移（即呼气末pCT和所有呼气末CBCT之间的位移）。运动定义为可用标记的质心位点（胃质心）的位移，变形定义为标记对之间的平均距离差。定量评估了间隙性（即呼气末pCT和所有呼气末CBCT之间）、呼吸（呼气末和吸气末pCT和CBCT之间）以及治疗前后（治疗前和治疗后呼气末CBCT之间）的运动和变形。间隙性标记位移在解剖区域和方向上各不相同，系统误差和随机误差分别介于1.6-8.8mm和2.2-8.2mm之间。呼吸运动在患者之间差异较大（3D振幅中位数为5.2-20.0mm），在一天内差异较小（四分位数范围为0.8-4.2mm）。就胃质心运动而言，呼吸运动大于间隙性运动（中位数分别为10.9和8.9mm；p<0.0001；Wilcoxon秩和检验），间隙性运动大于治疗前后运动（3.6mm；p<0.0001）。间隙性变形（中位数为5.8mm）明显大于治疗前后变形（2.6mm；p<0.0001），后者大于呼吸变形（1.8mm；p<0.0001）。放射治疗期间显著的胃运动和变形强调了术前胃癌放射治疗中对慷慨的非均匀PTV边缘的需求。这些边缘可以通过每日图像引导和适应性放射治疗来减小。版权所有 © 2023. Elsevier公司发表。

Selection and development of image-guided strategies for pre-operative gastric radiotherapy requires quantitative knowledge of the various sources of anatomical changes of the stomach. This study aims to investigate the magnitude of interfractional and intrafractional stomach motion and deformation using fiducial markers and 4D imaging.Fourteen patients who underwent pre-operative gastric cancer radiotherapy received 2-6 fiducial markers distributed throughout the stomach (total of 54 markers) and additional imaging (i.e., one planning 4DCT (pCT), 20-25 pre-treatment 4DCBCTs, 4-5 post-treatment 4DCBCTs). Marker coordinates on all end-exhale (EE) and end-inhale (EI) scans were obtained following a bony anatomy match. Interfractional marker displacements (i.e., between EE pCT and all EE CBCTs) were evaluated for five anatomical regions (i.e., cardia, small curvature, proximal and distal large curvature, and pylorus). Motion was defined as displacement of the center-of-mass of available markers (COMstomach), deformation as the average difference in marker-pair distances. Interfractional (i.e., between EE pCT and all EE CBCTs), respiratory (between EE and EI pCT and CBCTs), and pre-post (pre- and post-treatment EE CBCTs) motion and deformation were quantified.The interfractional marker displacement varied per anatomical region and direction, with systematic and random errors ranging from 1.6-8.8mm and 2.2-8.2mm, respectively. Respiratory motion varied per patient (median 3D amplitude 5.2-20.0mm) and day (interquartile range 0.8-4.2mm). Regarding COMstomach motion, respiratory motion was larger than interfractional motion (median 10.9 vs 8.9mm; p<0.0001; Wilcoxon rank-sum), which was larger than pre-post motion (3.6mm; p<0.0001). Interfractional deformations (median 5.8mm) were significantly larger than pre-post deformations (2.6mm; p<0.0001), which were larger than respiratory deformation (1.8mm; p<0.0001).The demonstrated sizable stomach motions and deformations during radiotherapy stress the need for generous non-uniform PTV margins for pre-operative gastric cancer radiotherapy. These margins can be decreased by daily image guidance and adaptive radiotherapy.Copyright © 2023. Published by Elsevier Inc.