PDF(Pubmed)
Abstract：
UNASSIGNED: Magnetic Resonance Imaging (MRI) guided stereotactic body radiotherapy (SBRT) of liver metastases is an upcoming high-precision non-invasive treatment. Interobserver variation (IOV) in tumor delineation, however, remains a relevant uncertainty for planning target volume (PTV) margins. The aims of this study were to quantify IOV in MRI-based delineation of the gross tumor volume (GTV) of liver metastases and to detect patient-specific factors influencing IOV.
UNASSIGNED: A total of 22 patients with liver metastases from three primary tumor origins were selected (colorectal(8), breast(6), lung(8)). Delineation guidelines and planning MRI-scans were provided to eight radiation oncologists who delineated all GTVs. All delineations were centrally peer reviewed to identify outliers not meeting the guidelines. Analyses were performed both in- and excluding outliers. IOV was quantified as the standard deviation (SD) of the perpendicular distance of each observer\'s delineation towards the median delineation. The correlation of IOV with shape regularity, tumor origin and volume was determined.
UNASSIGNED: Including all delineations, average IOV was 1.6 mm (range 0.6-3.3 mm). From 160 delineations, in total fourteen single delineations were marked as outliers after peer review. After excluding outliers, the average IOV was 1.3 mm (range 0.6-2.3 mm). There was no significant correlation between IOV and tumor origin or volume. However, there was a significant correlation between IOV and regularity (Spearman\'s ρs = -0.66; p = 0.002).
UNASSIGNED: MRI-based IOV in tumor delineation of liver metastases was 1.3-1.6 mm, from which PTV margins for IOV can be calculated. Tumor regularity and IOV were significantly correlated, potentially allowing for patient-specific margin calculation.
UNASSIGNED: A total of 22 patients with liver metastases from three primary tumor origins were selected (colorectal(8), breast(6), lung(8)). Delineation guidelines and planning MRI-scans were provided to eight radiation oncologists who delineated all GTVs. All delineations were centrally peer reviewed to identify outliers not meeting the guidelines. Analyses were performed both in- and excluding outliers. IOV was quantified as the standard deviation (SD) of the perpendicular distance of each observer\'s delineation towards the median delineation. The correlation of IOV with shape regularity, tumor origin and volume was determined.
UNASSIGNED: Including all delineations, average IOV was 1.6 mm (range 0.6-3.3 mm). From 160 delineations, in total fourteen single delineations were marked as outliers after peer review. After excluding outliers, the average IOV was 1.3 mm (range 0.6-2.3 mm). There was no significant correlation between IOV and tumor origin or volume. However, there was a significant correlation between IOV and regularity (Spearman\'s ρs = -0.66; p = 0.002).
UNASSIGNED: MRI-based IOV in tumor delineation of liver metastases was 1.3-1.6 mm, from which PTV margins for IOV can be calculated. Tumor regularity and IOV were significantly correlated, potentially allowing for patient-specific margin calculation.
摘要：
■肝转移瘤的磁共振成像（MRI）引导的立体定向放射治疗（SBRT）是即将到来的高精度非侵入性治疗。肿瘤描绘中的观察者间变异（IOV），然而,规划目标成交量(PTV)利润率仍然存在相关不确定性。这项研究的目的是在基于MRI的肝转移瘤总肿瘤体积（GTV）描绘中量化IOV，并检测影响IOV的患者特异性因素。
■共选择了22例来自三个原发肿瘤来源的肝转移患者（结直肠（8），乳房（6），肺（8））。向描绘所有GTV的八名放射肿瘤学家提供了描绘指南和计划MRI扫描。所有划界都进行了集中同行评审，以确定不符合指南的异常值。对异常值和排除异常值进行分析。IOV被量化为每个观察者的轮廓朝向中位数轮廓的垂直距离的标准偏差(SD)。IOV与形状规律性的相关性，确定肿瘤来源和体积。
■包括所有轮廓，平均IOV为1.6mm(范围0.6-3.3mm).从160个描述中，经过同行评审后，总共有14个单一轮廓被标记为异常值。排除异常值后，平均IOV为1.3mm（范围0.6-2.3mm）。IOV与肿瘤起源或体积之间没有显着相关性。然而,IOV与规律性之间存在显着相关性（Spearman'sρs=-0.66；p=0.002）。
■在肝转移的肿瘤勾画中基于MRI的IOV为1.3-1.6mm，可以从中计算IOV的PTV裕度。肿瘤规律性与IOV显著相关,可能允许患者特定的裕度计算。
■共选择了22例来自三个原发肿瘤来源的肝转移患者（结直肠（8），乳房（6），肺（8））。向描绘所有GTV的八名放射肿瘤学家提供了描绘指南和计划MRI扫描。所有划界都进行了集中同行评审，以确定不符合指南的异常值。对异常值和排除异常值进行分析。IOV被量化为每个观察者的轮廓朝向中位数轮廓的垂直距离的标准偏差(SD)。IOV与形状规律性的相关性，确定肿瘤来源和体积。
■包括所有轮廓，平均IOV为1.6mm(范围0.6-3.3mm).从160个描述中，经过同行评审后，总共有14个单一轮廓被标记为异常值。排除异常值后，平均IOV为1.3mm（范围0.6-2.3mm）。IOV与肿瘤起源或体积之间没有显着相关性。然而,IOV与规律性之间存在显着相关性（Spearman'sρs=-0.66；p=0.002）。
■在肝转移的肿瘤勾画中基于MRI的IOV为1.3-1.6mm，可以从中计算IOV的PTV裕度。肿瘤规律性与IOV显著相关,可能允许患者特定的裕度计算。
