Radiation Oncology Department, National Center for Cancer Care and Research, Doha, Qatar.
Radiother Oncol. 2013 Apr;107(1):6-12. doi: 10.1016/j.radonc.2013.01.014. Epub 2013 Feb 27.
We aimed to quantify target volume delineation uncertainties in cervix cancer image guided adaptive brachytherapy (IGABT).
Ten radiation oncologists delineated gross tumour volume (GTV), high- and intermediate-risk clinical target volume (HR CTV, IR CTV) in six patients. Their contours were compared with two reference delineations (STAPLE-Simultaneous Truth and Performance Level Estimation and EC- expert consensus) by calculating volumetric and planar conformity index (VCI and PCI) and inter-delineation distances (IDD).
VCISTAPLE and VCIEC were 0.76 and 0.72 for HR CTV, 0.77 and 0.68 for IR CTV and 0.59 and 0.58 for GTV. Variation was most prominent caudally and cranially in all target volumes and posterolaterally in IR CTV. IDDSTAPLE and IDDEC for HR CTV (3.6±3.5 and 3.8±3.4 mm) were significantly lower than for GTV (4.8±4.2 and 4.2±3.5 mm) and IR CTV (4.7±5.2 and 5.2±5.6 mm) (p<0.05).
Due to lower delineation uncertainties when compared to GTV and IR CTV, HR CTV may be considered most robust volume for dose prescription and optimization in cervix cancer IGABT. Adequate imaging, training and use of contouring recommendations are main strategies to minimize delineation uncertainties.
我们旨在量化宫颈癌图像引导自适应近距离治疗（IGABT）中靶区勾画的不确定性。
10 名放射肿瘤学家对 6 名患者的大体肿瘤体积（GTV）、高风险和中风险临床靶区（HR CTV、IR CTV）进行勾画。通过计算体积和平面一致性指数（VCI 和 PCI）以及勾画间距离（IDD），比较他们的勾画与两种参考勾画（STAPLE-同时真实和性能水平估计和 EC-专家共识）。
HR CTV 的 VCISTAPLE 和 VCIEC 分别为 0.76 和 0.72，IR CTV 分别为 0.77 和 0.68，GTV 分别为 0.59 和 0.58。在所有靶区中，变异最明显的是在头尾方向，而在 IR CTV 中则是在后外侧。HR CTV 的 IDDSTAPLE 和 IDDEC（3.6±3.5 和 3.8±3.4 mm）明显低于 GTV（4.8±4.2 和 4.2±3.5 mm）和 IR CTV（4.7±5.2 和 5.2±5.6 mm）（p<0.05）。
与 GTV 和 IR CTV 相比，HR CTV 的勾画不确定性较低，因此在宫颈癌 IGABT 中，HR CTV 可被认为是剂量处方和优化的最稳健体积。充分的影像学检查、培训和使用勾画建议是最大限度减少勾画不确定性的主要策略。
