摘要
目的 探讨基于4DCT的0%时相（CT0）及50%时相（CT50）刚性配准（RIR）与形变配准（DIR）所构建的保乳术后瘤床体积及位置的差异。方法 纳入44例保乳术后行4DCT定位扫描的乳腺癌患者,由同1名放疗科医师分别基于CT0及CT50图像勾画GTV及金属夹。CT0及CT50分别运行RIR与DIR,在CT0上勾画的GTV及金属夹分别通过DIR与RIR映射到CT50。以相似度指数（DSC）、三维空间方向上靶区中心点的位移等指标评估DIR在靶区位置和形态上是否能有效改善CT0及CT50的匹配度。结果 RIR与DIR的平均DSC分别为0.86±0.04、0.87±0.04（P=0.000）。RIR在三维空间靶区中心点的位移明显大于DIR （1.22 mm∶1.10 mm,P=0.000）。在前后方向上GTV及金属夹位移通过RIR的范围明显大于DIR （P=0.000）,但在左右及上下方向RIR与DIR的GTV及金属夹位移范围相近（P均〉0.05）。结论 DIR可以改善4DCT的CT0及CT50配准时靶区的重合度。基于DIR测量呼吸运动所致的GTV及金属夹在前后方向上的位移明显优于RIR。
Objective To compare the geometric differences of gross tumor volumes （GTV） and displacements of selected clips propagated by rigid image registration （RIR） and deformable image registration （DIR） at end-inhale phase （CT0） and end-exhale phase （CT50） based on four-dimensional computed tomography （4DCT） of the whole breast after breast-conserving surgery （BCS）. Methods Forty-four patients who underwent 4DCT simulation scans after BCS were selected. The GTV and displacements of selected metal clips at CT0 and CT50 were manually delineated by the same radiotherapy physician. Subsequently,the GTV and displacements of selected clips from CT0 images were transformed and propagated to CT50 images using RIR and DIR.The geometric differences of GTV and displacements of surgical clips from DIR were compared with those from RIR based on the dice similarity coefficient （DSC） and the displacements of the center of mass （COM） in the three-dimensional （3D） directions. Resutls The mean DSC was 0.86±0.04 for RIR and 0.87±0.04 for DIR （P=0.000）.The displacements of COM in 3D directions from RIR were significantly greater than those from DIR （1.22 mm vs. 1.10 mm,P=0.000）.In the anterior-posterior direction,the displacements from RIR were significantly greater than those from DIR for both GTV and selected clips （P=0.000）.However,in the left-right and superior-inferior directions,there were no significant differences in displacements between RIR and DIR for both GTV and the selected clips （all P〉0.05）. Conclutions DIR can improve the overlap for GTV registration from 4DCT scans at CT0 and CT50.Furthermore,DIR is superior to RIR in reflecting GTV and the displacements of selected clips in anterior-posterior direction induced by respiratory movement.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2017年第11期1280-1284,共5页
Chinese Journal of Radiation Oncology
基金
国家重点研发计划项目（2016YFC0904700）
关键词
部分乳腺外照射
四维CT
刚性配准
形变配准
呼吸运动
乳腺肿瘤
External partial breast irradiation
Four-dimensional computed tomography
Rigid image registration
Deformable image registration
Respiratory movement
Breast neoplasms
