| 摘要: |
| 目的探讨千伏级锥形束CT（CBCT）与X线透视成像在鼻咽癌影像引导调强放疗中摆位校正时的相关性及一致性。方法选择35例鼻咽癌患者为研究对象，治疗实施前均行正侧位的千伏级X线透视成像、千伏级CBCT检查，分别将正侧位千伏级X线透视图像、CBCT图像与治疗计划数字重建射野图像进行手动配准与自动的骨性配准，得出左右（x）、上下（y）、前后（z）等3个方向上的摆位误差值。应用Spearman相关分析两种图像采集方法的相关性，Bland-Altman绘图法检验两者的一致性。结果CBCT、千伏级X线透视成像在x、y、z方向的CTV-PTV外放边界（M_ptv）推荐值分别为0.41、0.56、0.31cm和0.36、0.50、0.43cm。两种图像采集方法在x、y、z方向所得的平移摆位误差结果均呈正相关（rs=0.634、0.869和0.735，均P＜0.05）。两种图像采集方法在x、y、z方向上的95%一致性限度分别为[0.26，-0.22]、[0.21，-0.23]、[0.21，-0.33]cm，提示两者所得的平移摆位误差缺乏足够的一致性。结论X线透视成像尚不能替代CBCT。考虑到千伏级X线透视成像的照射剂量较千伏级CBCT小一个数量级，临床上可根据实际情况联合运用两种方法。 |
| 关键词: 锥形束 CT 千伏级 X 线透视成像 图像配准 摆位误差 |
| DOI：10.12056/j.issn.1006-2785.2018.40.18.2018-933 |
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| Correlation and consistency between conebeam CT and orthogonal kV radiography in image-guided radiation therapy for nasopharyngeal carcinoma patients |
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Yinzhou People's Hospital
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| Abstract: |
| Objective To investigate the correlation and consistency between conebeam CT (CBCT) and orthogonal kV radiography in image-guided radiation therapy (IGRT) for nasopharyngeal carcinoma patients. Methods Thirty-five patients with nasopharyngeal carcinoma underwent IGRT, the orthogonal kV radiography images and the CBCT images were taken before the IGRT procedure. The images were matched with auto and manually methods on bony value and the setup errors in x, y and z axis were measured. Spearman correlation analysis was performed to evaluate the correlation of setup errors obtained from the two methods, and Bland-Altman plot analysis was performed to assess the consistency of two methods. Results The Spearman correlation coefficients of the two methods on x, y and z axis were 0.634, 0.869 and 0.735, respectively (P＜0.01). The 95% agreement limits in Bland-Altman plot analysis along x, y and z axis were[0.26,-0.22], [0.21,-0.23] and [0.21,-0.33]cm, which exceed the preset 0.2cm limits. Conclusion The results indicate that the setup errors of the two methods are correlated significantly, while there is lack of consistency, so kV radiography is not sufficient to be an alternative method of CBCT in measuring
setup errors in IGRT for nasopharyngeal carcinoma patients. |
| Key words: Conebeam CT Ｏrthogonal kV radiography Image matching Setup errors |
