PDF(Pubmed)
Abstract：
UNASSIGNED: Intra-fraction motion management is key in Stereotactic Ablative Radiotherapy (SABR) gated delivery. This study assessed the accuracy of automatic tumor segmentation in the delivery of MR-guided radiotherapy (MRgRT) by comparing it to manual delineations performed by experienced observers.
UNASSIGNED: Twenty patients previously treated with MR-guided SABR for thoracic and abdominal tumors were included. Five observers with at least two years of experience in MRgRT manually delineated the gross tumor volume (GTV) for 20 patients on 240 frames of a cine MRI on a sagittal plane. Deformable Image Registration (DIR) based GTV contours were propagated using four different algorithms from a reference frame to subsequent frames.Geometrical analysis based on the Dice Similarity Coefficient (DSC), centroid distance and Hausdorff Distance (HDD) were performed to assess the inter-observer variability and the accuracy of automatic segmentation. A Confidence Value (CV) metric for the reliability of the tumor auto-contouring was also calculated.
UNASSIGNED: Inter-observer delineation variability resulted in mean DSC of 0.89, HDD of 5.8 mm and centroid distance of 1.7 mm. Tumor auto-contouring by the four DIR algorithms resulted in an excellent agreement with the manual delineations by the experienced observers. Mean DSC for each algorithm across all patients was greater than 0.90, whereas the HDD and centroid distances were below 4.0 mm and 1.5 mm, respectively. The CV showed a strong correlation with the DSC.
UNASSIGNED: DIR-based auto-contouring in MRgRT exhibited a high level of agreement with the manual contouring performed by experts, allowing accurate gated delivery.
UNASSIGNED: Twenty patients previously treated with MR-guided SABR for thoracic and abdominal tumors were included. Five observers with at least two years of experience in MRgRT manually delineated the gross tumor volume (GTV) for 20 patients on 240 frames of a cine MRI on a sagittal plane. Deformable Image Registration (DIR) based GTV contours were propagated using four different algorithms from a reference frame to subsequent frames.Geometrical analysis based on the Dice Similarity Coefficient (DSC), centroid distance and Hausdorff Distance (HDD) were performed to assess the inter-observer variability and the accuracy of automatic segmentation. A Confidence Value (CV) metric for the reliability of the tumor auto-contouring was also calculated.
UNASSIGNED: Inter-observer delineation variability resulted in mean DSC of 0.89, HDD of 5.8 mm and centroid distance of 1.7 mm. Tumor auto-contouring by the four DIR algorithms resulted in an excellent agreement with the manual delineations by the experienced observers. Mean DSC for each algorithm across all patients was greater than 0.90, whereas the HDD and centroid distances were below 4.0 mm and 1.5 mm, respectively. The CV showed a strong correlation with the DSC.
UNASSIGNED: DIR-based auto-contouring in MRgRT exhibited a high level of agreement with the manual contouring performed by experts, allowing accurate gated delivery.
摘要：
■分数内运动管理是立体定向消融放射治疗（SABR）门控给药的关键。这项研究通过将其与经验丰富的观察者进行的手动描绘进行比较，评估了MR引导放射治疗（MRgRT）中自动肿瘤分割的准确性。
■包括20例先前接受MR引导SABR治疗的胸部和腹部肿瘤患者。五名具有至少两年MRgRT经验的观察者在矢状平面上的240帧电影MRI上手动描绘了20名患者的总肿瘤体积（GTV）。使用四种不同的算法将基于可变形图像配准(DIR)的GTV轮廓从参考帧传播到后续帧。基于骰子相似系数（DSC）的几何分析，执行质心距离和Hausdorff距离（HDD）以评估观察者之间的变异性和自动分割的准确性。还计算了肿瘤自动轮廓化的可靠性的置信值(CV)度量。
■观察者间的描绘可变性导致平均DSC为0.89,HDD为5.8mm,质心距离为1.7mm。通过四种DIR算法进行的肿瘤自动轮廓绘制与经验丰富的观察者的手动描绘非常吻合。所有患者的每个算法的平均DSC大于0.90，而HDD和质心距离小于4.0mm和1.5mm，分别。CV显示与DSC的强相关性。
■MRgRT中基于DIR的自动轮廓与专家进行的手动轮廓显示出高度的一致性，允许准确的门控交付。
■包括20例先前接受MR引导SABR治疗的胸部和腹部肿瘤患者。五名具有至少两年MRgRT经验的观察者在矢状平面上的240帧电影MRI上手动描绘了20名患者的总肿瘤体积（GTV）。使用四种不同的算法将基于可变形图像配准(DIR)的GTV轮廓从参考帧传播到后续帧。基于骰子相似系数（DSC）的几何分析，执行质心距离和Hausdorff距离（HDD）以评估观察者之间的变异性和自动分割的准确性。还计算了肿瘤自动轮廓化的可靠性的置信值(CV)度量。
■观察者间的描绘可变性导致平均DSC为0.89,HDD为5.8mm,质心距离为1.7mm。通过四种DIR算法进行的肿瘤自动轮廓绘制与经验丰富的观察者的手动描绘非常吻合。所有患者的每个算法的平均DSC大于0.90，而HDD和质心距离小于4.0mm和1.5mm，分别。CV显示与DSC的强相关性。
■MRgRT中基于DIR的自动轮廓与专家进行的手动轮廓显示出高度的一致性，允许准确的门控交付。
