Dimopoulos Johannes C A, De Vos Veronique, Berger Daniel, Petric Primoz, Dumas Isabelle, Kirisits Christian, Shenfield Carey B, Haie-Meder Christine, Pötter Richard
Department of Radiotherapy, Medical University of Vienna, Vienna, Austria.
Radiother Oncol. 2009 May;91(2):166-72. doi: 10.1016/j.radonc.2008.10.023. Epub 2008 Dec 4.
To investigate the inter-observer variation of target contouring when using the GYN GEC-ESTRO recommendations for MR image-guided brachytherapy (IGBT) for cervical cancer.
Nineteen cervical cancer patients, treated by radiotherapy at the Institut Gustave Roussy (IGR) in France (n=9) or at the Medical University of Vienna (AKH) in Austria (n=10) were included in this study. IGBT was used for all patients. Two radiation oncologists, one from IGR and the other from AKH, outlined the target volumes on MRI at the time of brachytherapy according to the GYN GEC-ESTRO recommendations. The absolute, common and encompassing volumes and their conformity indices (CIs) were assessed for the GTV, HR CTV and IR CTV. D90 and D100 for each volume were assessed. Visual evaluation was made to assess the reasons for the most frequent inter-observer differences.
The mean volumes of GTV and HR CTV did not differ significantly between the observers, p>0.05. Significant differences were observed only for the mean volumes of the IR CTV of both centres, p<0.05. CIs ranged from 0.5 to 0.7. DVH-parameter analyses did not reveal any statistical differences, except for the D100 for the GTV at AKH, and the D90 for the IR CTV at IGR, p<0.05. Underlying reasons for inter-observer differences included image contrast adjustment and neglecting to consider anatomical borders.
The results of this inter-observer study show that the application of the GYN GEC-ESTRO recommendations for IGBT contouring at two different institutions with two different traditions for applicators, CTV assessment, MR image acquisition and dose prescription is feasible, and it produces acceptable inter-observer variability.
研究在使用GYN GEC-ESTRO关于宫颈癌磁共振图像引导近距离放射治疗（IGBT）的建议时，不同观察者在靶区轮廓勾画方面的差异。
本研究纳入了19例宫颈癌患者，其中9例在法国古斯塔夫·鲁西研究所（IGR）接受放疗，10例在奥地利维也纳医科大学（AKH）接受放疗。所有患者均采用IGBT治疗。两名放射肿瘤学家，一名来自IGR，另一名来自AKH，在近距离放射治疗时根据GYN GEC-ESTRO建议在磁共振成像上勾画靶区体积。对大体肿瘤体积（GTV）、高危临床靶区（HR CTV）和低危临床靶区（IR CTV）的绝对体积、共同体积和包容体积及其适形指数（CIs）进行评估。评估每个体积的D90和D100。进行视觉评估以分析观察者间最常见差异的原因。
观察者之间GTV和HR CTV的平均体积无显著差异，p>0.05。仅两个中心的IR CTV平均体积存在显著差异，p<0.05。CIs范围为0.5至0.7。除了AKH的GTV的D100和IGR的IR CTV的D90外，剂量体积直方图（DVH）参数分析未显示任何统计学差异，p<0.05。观察者间差异的潜在原因包括图像对比度调整和未考虑解剖边界。
这项观察者间研究的结果表明，在两个具有不同施源器使用传统、CTV评估、磁共振图像采集和剂量处方的不同机构中，应用GYN GEC-ESTRO关于IGBT轮廓勾画的建议是可行的，并且产生了可接受的观察者间变异性。
