图像引导放疗技术对提高脊柱转移瘤摆位精度的临床研究

目的：应用西门子CT Vision图像引导系统纠正脊柱转移瘤在行三维适形或调强放疗的摆位误差,以提高放疗精度。方法：回顾分析20例脊柱转移瘤患者应用CT Vision行图像引导的影像学资料,每位患者隔日在放疗前行CT图像引导,将实时扫描的CT图像与放疗计划时的参考CT图像作融合比较,分析比较图像引导纠正摆位误差前和纠正摆位误差后患者在左右、头脚、前后方向上的误差。结果：颈椎、胸椎、腰椎骨转移瘤分别为4、7、9例;放疗前CT引导图像与计划时参考CT图像比较在左右、头脚、前后方向上的平均误差分别为（1.7±0.9、2.1±0.6、2.3±0.8）mm、（1.9±1.1、1.5±1.7、3.0±1.9）mm、（2.5±0.5、1.8±2.0、-2.2±3.2）mm;纠正摆位误差后重新行CT扫描,在三维方向上的平均误差分别为（0.7±0.2、0.5±0.8、0.3±0.7）mm、（1.1±0.3、0.3±0.8、0.9±0.6）mm、（0.8±0.4、0.6±0.5、-0.2±1.1）mm。结论：脊椎转移瘤患者在放疗前行CT Vision图像引导可使放疗摆位精度控制在2 mm以内,对提高靶区照射剂量及保护脊髓有重要意义。

Image guided radiotherapy enhances the precision of radiotherapy for vertebra metastasis

Objective： To evaluate the precision of image guided radiotherapy（IGRT） for vertebra metastasis using CT Vision. Methods ： Retrospective analysis of CT Vision line image guided imaging data from 20 cases of patients with spinal metastases application CT Vision line image guided imaging data, Each patient underwent CT image guidance before radiotherapy on alternate days. The set-up errors in the left-right,cervical-caudal and anterior-pos- terior directions of error were analyzed and compaired. Results： Compared to the acquired CT images,the average errors of 4 cases of cervical bone metastases in the left-right, cervical-caudal and anterior-posterior directions were （ 1.7 ±0.9,2.1 ±0.6,2.3 ±0.8） mm ,respectively. After adjusting the isocenter,the new errors were（0.7 -±0.2, 0.5 ± 0.8,0.3 ± 0.7 ） mm. The average errors of 7cases of thoracic bone metastases in the three dimensional direc- tions were （ 1.9 ± 1.1,1.5 ± 1.7,3.0 ± 1.9 ） mm, respectively. After adjusting the isocenter, the new errors were （ 1.1 ±0.3,0.3 ±0.8,0.9 ±0.6） mm. The average errors of 9 cases of lumbar bone metastases in the three di- mensional directions were （2.5 ± 0.5,1.8 ± 2.0± -2.2 ± 3.2） mm, respectively. After adjusting the isocenter, the new errors were（ 0.8 ± 0.4,0.6 ±0.5,-0.2 ± 1.1 ） mm. Conclusion： IGRT can improve the precision of radio- therapy for vertebra metastasis to less than 2 ram, it has important significance to improve the target dose and to protect spinal cord.