CAJ | 학술논문

目的基于4DCT模拟定位增强扫描探讨放疗不同时段胸段食管癌GTV50、IGTV空间位置及重合度变化.方法对33例胸段食管癌患者于放疗前及放疗10次、20次时行4DCT模拟定位增强扫描,分别在每次扫描各时相图像上勾画食管癌GTV50并构建IGTV.比较不同时段靶体积大小、DI和MI.结果疗程中GTV50、IGTV体积均呈递减趋势,两靶区中心点位置变化均不明显.初始靶区对放疗10次、20次GTV50的DI分别为0.75、0.63(P =0.000),IGTV的分别为0.79、0.66(P=0.000);GTV50的MI分别为0.61、0.56(P=0.002),IGTV的分别为0.68、0.58(P =0.005).两靶体积比变化与初始各靶区对疗程中各靶区DI变化均呈正相关(r=0.632,r =0.783),与MI亦均呈正相关(r =0.387,r =0.483),三维运动矢量与MI均呈负相关(r=-0.455,r=-0.438).结论胸段食管癌原发灶常规剂量分割放疗时GTV50、IGTV空间位置变化均＜0.8 cm,同时放疗中靶区退缩致使靶区DI及MI出现不同程度下降.
목적 기우4DCT모의정위증강소묘탐토방료불동시단흉단식관암GTV50、IGTV공간위치급중합도변화.방법 대33례흉단식관암환자우방료전급방료10차、20차시행4DCT모의정위증강소묘,분별재매차소묘각시상도상상구화식관암GTV50병구건IGTV.비교불동시단파체적대소、DI화MI.결과 료정중GTV50、IGTV체적균정체감추세,량파구중심점위치변화균불명현.초시파구대방료10차、20차GTV50적DI분별위0.75、0.63(P =0.000),IGTV적분별위0.79、0.66(P=0.000);GTV50적MI분별위0.61、0.56(P=0.002),IGTV적분별위0.68、0.58(P =0.005).량파체적비변화여초시각파구대료정중각파구DI변화균정정상관(r=0.632,r =0.783),여MI역균정정상관(r =0.387,r =0.483),삼유운동시량여MI균정부상관(r=-0.455,r=-0.438).결론 흉단식관암원발조상규제량분할방료시GTV50、IGTV공간위치변화균＜0.8 cm,동시방료중파구퇴축치사파구DI급MI출현불동정도하강.
Objective To investigate the variations of the spatial position and overlap ratio for gross tumor volume (respiratory phase 50％) (GTV50) and internal gross tumor volume (IGTV) of primary thoracic esophageal cancer during conventional fractionated radiotherapy based on repeated four-dimensional computed tomography (4DCT) scans.Methods Thirty-three patients with thoracic esophageal cancer underwent contrast-enhanced 4DCT scans before radiotherapy and at the 10th and 20th fractions of radiotherapy.Scans were registered to the baseline 4DCT scan using bony landmarks.The GTV50 was delineated by the same radiotherapist on each 4DCT imaging data set,and the IGTV was constructed accordingly.The target volume,degree of inclusion (DI),and matching index (MI) were compared in different phases.Results The volumes of GTV50 and IGTV decreased along with treatment course.No significant changes in the centroid position were observed for the GTV50 and IGTV.The median DIs of the target volumes at the 10th and 20th fractions in the original target volume were 0.75 and 0.63(P =0.000) for GTV50 and were 0.79 and 0.66(P=0.000) for IGTV,while the median MIs were 0.61 and 0.56(P=0.002) for GTV50 and were 0.68 and 0.58 (P =0.005) for IGTV.A positive correlation between the variation of volume ratio and the variation of DI was found for GTV50 and IGTV (r =0.632,r =0.783),and the variation of volume ratio was also positively correlated with the variation of MI (r =0.387,r =0.483) ;the 3D vector was negatively correlated with the MI (r =-0.455,r =-0.438).Conclusions During conventional fractionated radiotherapy,the variation of spatial position is less than 0.8 cm for GTV50 and IGTV of primary thoracic esophageal cancer,and the decline of the target leads to varying degrees of decreases in DI and the MI.