肺癌图像引导放射治疗中基于不同解剖标志图像配准的研究

Study of image registration based on different anatomical landmarkers in image-guided radiotherapy for lung cancer

目的评估以不同的解剖标志进行图像配准相较于肿瘤区域配准在中央型肺癌图像引导放射治疗(IGRT)中的差异。方法选择在我院行IGRT的中央型肺癌患者50例,分别以胸骨柄、胸椎、气管隆突和肿瘤肿块为解剖标志,将CBCT与计划CT图像进行配准,分别获得左右(X轴)、头脚(Y轴)和前后(Z轴)方向的图像配准误差实际值和绝对值,分析各组与肿瘤肿块组间的差异。结果在X、Y、Z轴上,胸骨柄、胸椎、气管隆突和肿瘤肿块的配准误差实际值分别为:(-0.02±0.23)、(0.03±0.21)、(0.04±0.27)、(0.03±0.25)cm;(-0.08±0.33)、(0.11±0.32)、(0.07±0.30)、(0.04±0.27)cm;(-0.22±0.17)、(-0.00±0.16)、(-0.01±0.22)、(-0.03±0.23)cm,其中,Y、Z轴上胸骨柄和肿瘤肿块组间误差实际值比较,差异有统计学意义(P<0.05),而气管隆突、胸椎和肿瘤肿块组间误差实际值比较,差异无统计学意义(P>0.05),但气管隆突优于胸椎。结论在中央型肺癌IGRT中,以不同的解剖标志进行图像配准存在差异,但气管隆突、胸椎和肿瘤肿块组间无明显差异,气管隆突和胸椎均可以代替肿瘤进行配准,且气管隆突更优。

Objective To evaluate the difference between image registration with different anatomical landmarks and tumor mass registration in image-guided radiotherapy(IGRT)for central lung cancer.Methods A total of 50 patients with central lung cancer who underwent IGRT in our hospital were selected.CBCT was registered with planned CT images using sternal stalk,thoracic vertebrae,tracheal carina and tumor mass as anatomical landmarks,and the actual and absolute values of image registration errors in left and right(X axis),head and foot(Y axis)and front and rear(Z axis)directions were obtained respectively.The differences between each group and tumor mass group were analyzed.Results On the X,Y and Z axis,the actual value of registration error of sternal stalk,thoracic vertebrae,tracheal carina and tumor mass were(-0.02±0.23),(0.03±0.21),(0.04±0.27),(0.03±0.25)cm;(-0.08±0.33),(0.11±0.32),(0.07±0.30),(0.04±0.27)cm;(-0.22±0.17),(-0.00±0.16),(-0.01±0.22),(-0.03±0.23)cm,respectively.On the Y and Z axis,there were significant differences in the actual value of error between the sternum stalk and the tumor mass(P<0.05).There were no significant differences in the actual value of error among the groups of tracheal carina,thoracic vertebrae and tumor mass(P>0.05),but that in tracheal carina was better than thoracic vertebrae.Conclusion In IGRT of central lung cancer,there are differences in image registration with different anatomical markers.But,there are no significant differences between tracheal carina,thoracic vertebrae and tumor mass.It is suggested that tracheal carina and thoracic vertebrae can replace tumor mass for image registration,and tracheal carina is better.