配准方式及范围选取对鼻咽癌调强放射治疗摆位误差的影响

The Influence between Registration-algorithms and Multiple Regions-of-interest of Setup Errors For Intensity Modulated Radiotherapy in Nasopharyngeal Carcinoma

目的在锥形束CT配准时选用不同方法和配准范围,研究调强放射治疗对鼻咽癌摆位误差的影响。方法入组20例调强放射治疗的鼻咽癌患者。首次治疗时在治疗机下患者摆位的锥形束CT(Cone-beam CT,CBCT)图像。配准算法选用灰度配准和骨性配准,配准范围选择眉骨上界至上下牙齿分界,上下牙齿分界至颈部下界,及前两部分全部选择。组合出6种方案与计划CT图像进行配准,获得各组的摆位误差。研究不同方案的差异。结果骨配准全范围与灰度配准全范围的y,Rx,Ry值比较,差异有统计学意义(P<0.05)。骨配准全范围与颈部灰度配准的x,z,Rx值比较,差异有统计学意义(P<0.05)。结论配准中范围选择加入颈部和不加入颈部时采用骨性配准和灰度配准比较,差异有统计学意义。应密切注意鼻咽癌颈部的摆位误差,提高颈部剂量的准确性。

Objective During registration of cone-beam CT images and planning CT, this paper investigated the effect of setup errors for the different registration-algorithms and multiple regions-of-interest for nasopharyngeal carcinoma for intensity-modulated radiotherapy（IMRT）.Methods 20 nasopharyngeal carcinoma patients were enrolled for IMRT. Each patient received Cone-beam CT（CBCT） during the first fraction of treatment. The registration-algorithms were selected bone and gray registration. There were three kinds of regions-of-interest, including between brow ridge to top teeth, between bottom teeth to neck and whole region. Six methods were selected to match CBCT and planning CT and get setup errors. The differences to six methods were evaluated.Results There were statistically significant differences between the whole of bone algorithm to the whole of gray algorithm in y,Rx,Ry（P〈0.05）. There were statistically significant differences between the whole of bone algorithm to the bottom teeth of gray algorithm in x,z,Rx（P〈0.05）. Conclusion There were statistically significant differences when the registration-algorithms included neck. We should pay attention to the neck setup errors for nasopharyngeal carcinoma radiotherapy and improve the precise of treatment for neck region.