Duane Frances K, Langan Brian, Gillham Charles, Walsh Lorraine, Rangaswamy Guhan, Lyons Ciara, Dunne Mary, Walker Christopher, McArdle Orla
Department of Radiation Oncology, St. Luke's Radiation Oncology Network, Rathgar, Dublin, Republic of Ireland.
Department of Medical Physics, St. Luke's Radiation Oncology Network, Rathgar, Dublin, Republic of Ireland.
Brachytherapy. 2014 Mar-Apr;13(2):210-8. doi: 10.1016/j.brachy.2013.08.010. Epub 2013 Oct 3.
This study quantifies the inter- and intraobserver variations in contouring the organs at risk (OARs) in CT-guided brachytherapy (BT) for the treatment of cervical carcinoma. The dosimetric consequences are reported in accordance with the current Gynecological Groupe Européen de Curiethérapie/European Society for Therapeutic Radiology and Oncology guidelines.
A CT planning study of 8 consecutive patients undergoing image-guided BT was conducted. The bladder, rectum, and sigmoid were contoured by five blinded observers on two identical anonymized scans of each patient. This provided 80 data sets for analysis. Dosimetric parameters analyzed were D0.1 cc, D1 cc, and D2 cc. The mean volume of each OAR was calculated. These endpoints were compared between and within the observers. The CT image sets from all patients were evaluated qualitatively.
The interobserver coefficient of variation for reported D2 cc was 13.2% for the bladder, 9% for the rectum, and 19.9% for the sigmoid colon. Unlike the variation seen in bladder and rectal contours, which differed largely in localization of the organ walls on individual slices, sigmoid colon contours demonstrated large differences in anatomic interpretation.
Variation in recorded D2 cc to the bladder and rectum is comparable with the previous published results. Inter- and intraphysician variations in reported D2 cc is high for the sigmoid colon, reflecting varying interpretation of sigmoid colon anatomy. Variation in delineation of the OARs may influence treatment optimization and is a potential source of uncertainty in the image-guided BT planning and delivery process.
本研究量化了在CT引导下近距离放射治疗（BT）宫颈癌时，勾画危及器官（OARs）的观察者间和观察者内差异。根据当前欧洲妇科近距离放射治疗协作组/欧洲放射肿瘤学会指南报告剂量学结果。
对8例连续接受图像引导BT的患者进行CT计划研究。5名不知情的观察者在每位患者的两次相同匿名扫描上勾画膀胱、直肠和乙状结肠。这提供了80个数据集用于分析。分析的剂量学参数为D0.1 cc、D1 cc和D2 cc。计算每个OAR的平均体积。在观察者之间和观察者内部比较这些终点。对所有患者的CT图像集进行定性评估。
报告的膀胱D2 cc的观察者间变异系数为13.2%，直肠为9%，乙状结肠为19.9%。与膀胱和直肠轮廓的变异不同，膀胱和直肠轮廓在各层上器官壁的定位有很大差异，乙状结肠轮廓在解剖学解释上有很大差异。
记录的膀胱和直肠D2 cc的变异与先前发表的结果相当。乙状结肠报告的D2 cc的医师间和医师内变异较高，反映了对乙状结肠解剖结构的不同解释。OARs勾画的变异可能影响治疗优化，并且是图像引导BT计划和实施过程中不确定性的潜在来源。
