Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy.
Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy.
复制标题
DOI：
10.1088/0031-9155/60/24/9437
复制
发表时间：
2015-12-21
影响因子：
3.5
通讯作者：
Feain I
中科院分区：
文献类型：
--
作者：
Shieh CC;Keall PJ;Kuncic Z;Huang CY;Feain I
在没有植入标记物的情况下监测肿瘤运动的能力在临床上有利于肺部图像引导放射治疗（IGRT）。现有的无标记跟踪方法通常遭受重叠结构和kV投影图像上的肿瘤的低可见性。我们引入短弧肿瘤跟踪（SATT）方法来克服这些问题。所提出的方法利用从九度成像弧中选择的多个kV投影图像来改善肿瘤定位，并利用相关的4D锥形束CT（CBCT）先验知识来最大限度地减少重叠解剖结构的影响。3D肿瘤位置被解决为具有通过正则化并入的先验知识的优化问题。我们回顾性地验证了SATT的11个临床扫描从4例中央肿瘤。由于相邻对比度较差，这些患者代表了无标记肿瘤跟踪的挑战性场景。植入的基准标记的3D轨迹被用作跟踪精度评估的基础事实。在所有情况下，肿瘤在所有机架角度都被成功跟踪。与单独的标准治疗前CBCT引导相比，在所有情况下，跟踪的轨迹误差显著较小，并且在上下（SI）方向上的改善最为突出。平均3D跟踪误差范围为2.2-9.9 mm，比治疗前CBCT小0.4-2.6 mm。总之，我们能够使用SATT在kV投影图像上直接跟踪可见性较差的肿瘤。与目前的肺部IGRT护理标准相比，跟踪的肿瘤定位准确性明显更好。未来的工作涉及SATT的前瞻性评价和临床实施。
The ability to monitor tumor motion without implanted markers is clinically advantageous for lung image-guided radiotherapy (IGRT). Existing markerless tracking methods often suffer from overlapping structures and low visibility of tumors on kV projection images. We introduce the short arc tumor tracking (SATT) method to overcome these issues. The proposed method utilizes multiple kV projection images selected from a nine-degree imaging arc to improve tumor localization, and respiratory-correlated 4D cone-beam CT (CBCT) prior knowledge to minimize the effects of overlapping anatomies. The 3D tumor position is solved as an optimization problem with prior knowledge incorporated via regularization. We retrospectively validated SATT on 11 clinical scans from four patients with central tumors. These patients represent challenging scenarios for markerless tumor tracking due to the inferior adjacent contrast. The 3D trajectories of implanted fiducial markers were used as the ground truth for tracking accuracy evaluation. In all cases, the tumors were successfully tracked at all gantry angles. Compared to standard pre-treatment CBCT guidance alone, trajectory errors were significantly smaller with tracking in all cases, and the improvements were the most prominent in the superior-inferior (SI) direction. The mean 3D tracking error ranged from 2.2–9.9 mm, which was 0.4–2.6 mm smaller compared to pre-treatment CBCT. In conclusion, we were able to directly track tumors with inferior visibility on kV projection images using SATT. Tumor localization accuracies are significantly better with tracking compared to the current standard of care of lung IGRT. Future work involves the prospective evaluation and clinical implementation of SATT.