基于CTVision图像引导肺癌放疗过程中的肿瘤体积变化及位移研究

Tumor volume change and displacement in patients with lung carcinoma during CTVision-guided radiotherapy

目的:基于西门子CTVision图像引导肺癌自适应放疗过程,分析患者肿瘤体积及位移变化情况。方法:采集11例肺癌患者放疗CT图像,与计划CT图像进行图像配准,比较放疗前与放疗中期肿瘤体积退缩情况以及在左、右、腹、背、头和脚这6个方向上的位置变化。结果:经自适应放疗,放疗中期11位患者肿瘤体积均有缩小,平均退缩率为43.2%,平均每天的退缩率为1.1%。患者肿瘤完全退缩为0例,微小退缩为4例,稳定退缩的肿瘤病灶为7例。大体肿瘤在左、脚、背侧位移最大,放疗前与放疗中期在6个方向上的位移有统计学意义(P<0.05)。结论:肺癌放疗过程中,靶区体积会发生一定程度的退缩,且位移改变较明显,应在放疗过程中根据靶区体积和位置的变化情况,对放疗计划进行必要的调整。

Objective To investigate the changes of tumor volume and tumor displacement in patients with lung cancer during treatment with adaptive radiation therapy guided by SIEMENS CTVision. Methods CT images were collected from 11 patients with lung cancer before and during radiotherapy and co-registered with the planning CT images to analyze the changes in tumor volume and tumor displacement in the left, right, anterior, posterior, superior, and inferior directions after a radiotherapeutic dose of 40 Gy. Results After receiving a radiotherapeutic dose of 40 Gy, all the 11 patients showed reduced tumor volume by 43.2% on average with a mean daily tumor volume reduction rate of 1.1%. Minor tumor volume reduction was observed in 4 cases and stable tumor reduction in 7 cases. Maximal displacement of the gross target volume （GTV） of the tumor was observed in the left, inferior, and posterior directions, and the GTV showed significant displacement in all the 6 directions after the patients had received a radiotherapy dose of 40 Gy （P〈0.05）. Conclusion Radiotherapy can cause reduction in the GTV volume and obvious GTV displacement of lung cancer between treatment fractions, and the radiotherapy plan should be adjusted accordingly during the treatment to ensure accurate radiation delivery to the target.