3种配准方式下头颈部肿瘤IGRT摆位误差的比较

Comparison of IGRT placement errors in head and neck neoplasms with three registration modes

目的研究头颈部肿瘤图像引导放射治疗(IGRT)中不同图像配准方法对放疗摆位误差的影响。方法使用西门子CTVision直线加速器分别治疗头颈部肿瘤患者22例,患者治疗前均行滑轨CT(CT-on-rail)扫描,获得的CT图像与原放疗计划CT图像进行配准,分析X、Y、Z轴方向的平移误差,比较骨性、灰度值及手动3种配准方式间的差异。结果经114次滑轨CT扫描治疗前头颈部肿瘤患者(22例),手动配准、骨性配准、灰度值配准3种配准方式结果均显示X轴平移误差最大,其次为Y轴,Z轴最小,但是3种配准方式结果差异无统计学意义。结论头颈部肿瘤患者行IGRT时,应用CT-on-rail系统可缩小摆位误差,建议首选骨性配准,实际操作过程中可结合手动微调,直到结果满足配准需要。

Objective To investigate the optimal alignment methods for the treatment of head and neck tumor in IGRT. Methods Siemens CTVision system was used to treat 22 patients with head and neck tumor respectively. CT-on-rail images received before every treatment fraction. The differences of bone, gray value and manual three registration methods were compared. Results 22 patients with head and neck tumor were followed up for 114 scans on CT-on-rail before treatment. The results of manual alignment, bone alignment and grey alignment showed that X- axis set-up error was the largest, followed by Y-axis and Z-axis. But there was no significant difference in the three alignment methods. Conclusion CT-on-rail system can reduce the set-up error in IGRT of head and neck tumor. Bone registration is preferred, and manual adjustment can be used in practice until the results meet the registration requirements.