射波刀脊柱追踪仰卧与俯卧位照射精度的对比

Comparison of the Spine Tracking Accuracy between Supine and Prone Position Setups in Cyber Knife Treatment

目的利用头颈、仿真人和肺部模体检测射波刀IGRT治疗脊柱追踪时仰卧与俯卧位照射精度并进行对比分析,为俯卧位脊柱追踪的应用提供参考数据。方法用CT对装有胶片的头颈、仿真人和肺部模体分别进行仰卧和俯卧位扫描,然后利用治疗计划系统分别设计仰卧和俯卧位模体计划,执行模体计划。利用E2E软件分析照射精度,对比这种两种卧姿的照射精度。结果仰卧与俯卧位精度检测结果,颈椎的追踪精度分别为0.77和0.87 mm,胸椎的为0.78和0.76 mm,腰椎的为0.89和0.80 mm,骶椎的为1.90和2.27 mm,4个不同椎体仰卧与俯卧位精度偏差分别为:0.01、0.02、0.09和0.37 mm。结论对于这三种静态模体,颈椎、胸椎、腰椎和骶椎仰卧与俯卧位脊柱追踪精度偏差很小,可以认为具有同等的照射精度。

Objective Using head and neck, anthropomorphic and lung phantoms to detect the spine tracking accuracy during CyberKnife IGRT treatment, compare the results in supine and prone positions and analyze them, to provide theoretical foundation for the application of supine position in spine tracking system. Methods Scan with CT the head and neck phantom with films, anthropomorphic phantom and lung phantom in supine and prone positions, respectively, then design treatment plans and delivery those plans. Compare and analyze the radiation accuracy of the two different positions with E2E software. Results The cervical vertebra tracking accuracy in supine and prone positions is 0.77 and 0.87 mm, respectively, with a difference of 0.01 mm; for thoracic vertebra tracking, the accuracy is 0.78 and 0.76 mm, respectively, with a difference of 0.02 mm; for lumbar vertebra, 0.89 and 0.80 ram, respectively with a difference of 0.09 mm; and for sacral vertebrae, 1.90 and 2.27 ram, with a difference of 0.37 ram. Conclusion For the three static phantoms, the differences of spine tracking accuracy between supine and prone position setups are very small. Therefore the accuracy in the two different positions can he considered equal.