Laboratory of Radiation Physics, Odense University Hospital, Odense, Denmark.
Danish Centre for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark.
Acta Oncol. 2021 Nov;60(11):1548-1554. doi: 10.1080/0284186X.2021.1975813. Epub 2021 Oct 9.
The Danish Neuro Oncology Group (DNOG) has established national consensus guidelines for the delineation of organs at risk (OAR) structures based on published literature. This study was conducted to finalise these guidelines and evaluate the inter-observer variability of the delineated OAR structures by expert observers.
The DNOG delineation guidelines were formed by participants from all Danish centres that treat brain tumours with radiotherapy. In a two-day workshop, guidelines were discussed and finalised based on a pilot study. Following this, the ten participants contoured the following OARs on T1-weighted gadolinium enhanced MRI from 13 patients with brain tumours: optic tracts, optic nerves, chiasm, spinal cord, brainstem, pituitary gland and hippocampus. The metrics used for comparison were the Dice similarity coefficient (Dice), mean surface distance (MSD) and others.
A total of 968 contours were delineated across the 13 patients. On average eight (range six to nine) individual contour sets were made per patient. Good agreement was found across all structures with a median MSD below 1 mm for most structures, with the chiasm performing the best with a median MSD of 0.45 mm. The Dice was as expected highly volume dependent, the brainstem (the largest structure) had the highest Dice value with a median of 0.89 whereas smaller volumes such as the chiasm had a Dice of 0.71.
Except for the caudal definition of the spinal cord, the variances observed in the contours of OARs in the brain were generally low and consistent. Surface mapping revealed sub-regions of higher variance for some organs. The data set is being prepared as a validation data set for auto-segmentation algorithms for use within the Danish Comprehensive Cancer Centre - Radiotherapy and potential collaborators.
丹麦神经肿瘤学组（DNOG）根据已发表的文献制定了用于勾画危及器官（OAR）结构的国家共识指南。本研究旨在最终确定这些指南，并通过专家观察者评估勾画的 OAR 结构的观察者间变异性。
DNOG 勾画指南由所有用放疗治疗脑肿瘤的丹麦中心的参与者制定。在为期两天的研讨会上，根据试点研究讨论并最终确定了指南。在此之后，10 名参与者根据 13 名脑肿瘤患者的 T1 加权钆增强 MRI 勾画了以下 OAR：视束、视神经、视交叉、脊髓、脑干、垂体和海马。用于比较的指标是 Dice 相似系数（Dice）、平均表面距离（MSD）和其他指标。
总共对 13 名患者的 968 个轮廓进行了勾画。平均每个患者有八套（范围为六到九套）独立的轮廓。大多数结构的平均 MSD 低于 1mm，表明所有结构之间的一致性较好，其中视交叉的表现最好，平均 MSD 为 0.45mm。Dice 与体积高度相关，脑干（最大的结构）的 Dice 值最高，中位数为 0.89，而较小的体积，如视交叉，Dice 值为 0.71。
除了脊髓尾部的定义外，大脑中 OAR 轮廓的观察到的变异性通常较低且一致。表面映射显示某些器官的某些亚区具有较高的变异性。该数据集正在准备作为用于丹麦综合癌症中心 - 放射治疗和潜在合作者的自动分割算法的验证数据集。
