周军

【摘 要】目的：探究体表标记辅助线在胸腹部肿瘤放疗中对摆位误差精度的影响。方法：随机选取80例需进行胸腹部放疗的患者，实验组以体表标记线辅助摆位，对照组正常摆位，之后用CBCT修正摆位误差，对摆位误差进行统计分析。结果：采用体表标记辅助线摆位的患者在X方向，Y方向上的误差减小，Z方向无明显变化。结论：体表标记辅助线明显提升胸腹部放疗病人的摆位精度。

【关键词】胸腹部肿瘤；体表标记辅助线；摆位误差；CBCT

Application of body surface marker auxiliary line in radiotherapy of thoracic and abdominal tumors

Zhoujun

Department of Oncology， Xinqiao Hospital， Military Medical University， Chongqing 400037， China

【Abstract】Objective：To investigate the effect of body surface marker-assisted line on the accuracy of placement error in thoracic and abdominal tumor radiotherapy. Methods：Eighty patients with thoracoabdominal radiotherapy were randomly selected. The experimental group was assisted by the body surface marker line， and the control group was placed normally. Then the CBCT was used to correct the placement error， and the placement error was statistically analyzed. Results：In the X direction， the error in the Y direction was reduced in the patient with the body surface marker auxiliary line placement， and there was no significant change in the Z direction. Conclusion：The surface marker auxiliary line significantly improves the placement accuracy of patients with thoracic and abdominal radiotherapy.

【Key words】thoracic and abdominal tumor， surface marker auxiliary line， placement error， CBCT

前言

调强放疗（intensity modulated radiation therapy，IMRT）是在各处辐射野与靶区外形一致的条件下，针对靶区三维形状和要害器官与靶区的具体解剖关系对束强度进行调节，单个辐射野内剂量分布是不均匀的但是整个靶区体积内剂量分布比三维适形治疗更均匀，可以使肿瘤靶区得到准确的剂量，但对摆位精确度提出了非常高的要求[1]。摆位的不准确不仅会使肿瘤靶区剂量不足，导致肿瘤的控制效果差，还有可能会使邻近的危及器官超量，造成严重的放疗并发症和后遗症。放疗误差分为分次内误差和摆位过程中的随机误差[2]。分次内误差主要由病人的隨机移动或周期性移动造成的，包含心脏跳动、呼吸运动和不自主的肌肉收缩等，是无法避免的[3]。随机误差是由不同治疗分次之间治疗时体位重复性的差异造成[4]。在治疗之前使用CBCT验证能够保证该次治疗的摆位误差精度，但影像获取的同时也会给病人带来额外的放射剂量[5]。在没有CBCT进行图像引导并且需要较长的治疗周期的情况下，摆位技术的提高对于放疗的精确度有直接影响。……