自研发变形配准软件在四维CT图像上确定靶体积的初步临床验证

Initial clinic verification of internal target volume generated with four-dimensional CT and deformable registration

目的 初步测试自研发变形配准软件在四维CT （4DCT）图像上快速确定临床靶体积（CTV）和呼吸运动内靶体积（ITV）精度,评估其临床应用可行性。方法 选择临床治疗的 1例肺癌和 1例肝癌的4DCT图像进行实验。用变形配准软件以单一呼吸时相CT图像勾画的CTV为参考自动生成其余呼吸时相的CTV defm ,并与放疗医师在每个呼吸时相CT图像勾画的CTV manu 比较,分析CTV defm 精度与适用范围。用CTV defm 叠加形成复合ITV comp ,并与最大密度投影（MIP） CT图像勾画的ITV MIP 比较轮廓、体积和几何中心位置差异。结果 肺癌病例10个呼吸时相4DCT图像序列的CTV defm 与CTV manu 体积偏差平均值为（－2.59±5.02）%。与CTV manu 相比,CTV defm 的几何中心三维矢量偏差为（1.04±0.89） mm。肝癌患者ITV comp 与ITV MIP 几何形状和位置几乎重合,体积差别〈1%,几何中心三维矢量差别为1.4 mm。结论 测试变形配准软件系统在4DCT图像上自动生成CTV和呼吸运动ITV精度可满足临床计划设计要求。

Objective To study preliminary the accuracy of clinical target volume （CTV） and internal target volume （ITV） automatically generated by an in-house deformable registration software on four-dimensional CT （4DCT）, and evaluate its feasibility of clinical application. Methods Clinic treated one lung cancer patient and one liver cancer patient were selected for the study. CTV manu was delineated by radiation oncologist according to a single respiratory phase image of 4DCT scanning, and then deformed to the other phases and generated the CTV defm on each phase image. Differences between the CTV defm and CTV manu were then compared. A composite ITVcopm was created by overlapping all the CTV defm of 10 phases and compared with the ITV MIP which was contoured on the maximum intensity projection （MIP） CT images, including the shape, volume and geometric center position of the ITV contour. Results For the tested lung case, average volume difference between the CTV defm and CTV manu was （-2.59±5.02）% for the all 10 phases, and the vector departure of the two ITV centers was （1.04±0.89） mm. The ITV comp almost completely matched the ITV MIP on the tested liver case with a volume difference smaller the 1% and only 1.4 mm vector departure between their geometric centers. Conclusion The validity of the CTV defm and ITV comp gained from automatic deformation of manual delineation reference based on 4DCT images were preliminary evaluated and proved to be good enough for clinic planning.